WO2023122968A1 - 帧内预测方法、设备、系统、及存储介质 - Google Patents

帧内预测方法、设备、系统、及存储介质 Download PDF

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Publication number
WO2023122968A1
WO2023122968A1 PCT/CN2021/142113 CN2021142113W WO2023122968A1 WO 2023122968 A1 WO2023122968 A1 WO 2023122968A1 CN 2021142113 W CN2021142113 W CN 2021142113W WO 2023122968 A1 WO2023122968 A1 WO 2023122968A1
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intra
prediction mode
current block
frame prediction
frame
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PCT/CN2021/142113
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English (en)
French (fr)
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谢志煌
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Oppo广东移动通信有限公司
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Priority to PCT/CN2021/142113 priority Critical patent/WO2023122968A1/zh
Publication of WO2023122968A1 publication Critical patent/WO2023122968A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/103—Selection of coding mode or of prediction mode
    • H04N19/105—Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/157—Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
    • H04N19/159—Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction

Definitions

  • the present application relates to the technical field of video coding and decoding, and in particular to an intra prediction method, device, system, and storage medium.
  • Digital video technology can be incorporated into a variety of video devices, such as digital televisions, smartphones, computers, e-readers, or video players, among others.
  • video devices implement video compression technology to enable more effective transmission or storage of video data.
  • Video is compressed through encoding, and the encoding process includes prediction, transformation, and quantization. For example, through intra-frame prediction and/or inter-frame prediction, determine the prediction block of the current block, subtract the prediction block from the current block to obtain a residual block, transform the residual block to obtain a transformation coefficient, and quantize the transformation coefficient to obtain a quantization coefficient, And encode the quantized coefficients to form a code stream.
  • two or more intra-frame prediction modes can be used to perform weighted fusion prediction on the current block to obtain the prediction value of the current block.
  • the prediction quality will be reduced instead.
  • Embodiments of the present application provide an intra prediction method, device, system, and storage medium, which determine whether to perform weighted fusion prediction based on image content, realize differentiated weighted fusion prediction, and further improve the accuracy of intra prediction.
  • an intra prediction method including:
  • the embodiment of the present application provides an intra prediction method, including:
  • the present application provides an intra prediction device, configured to execute the method in the above first aspect or its various implementation manners.
  • the encoder includes a functional unit configured to execute the method in the above first aspect or its implementations.
  • the present application provides an intra-frame prediction device, configured to perform the method in the above-mentioned second aspect or various implementations thereof.
  • the decoder includes a functional unit configured to execute the method in the above second aspect or its various implementations.
  • a video encoder including a processor and a memory.
  • the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory, so as to execute the method in the above first aspect or its various implementations.
  • a sixth aspect provides a video decoder, including a processor and a memory.
  • the memory is used to store a computer program
  • the processor is used to invoke and run the computer program stored in the memory, so as to execute the method in the above second aspect or its various implementations.
  • a video codec system including a video encoder and a video decoder.
  • the video encoder is configured to execute the method in the above first aspect or its various implementations
  • the video decoder is configured to execute the method in the above second aspect or its various implementations.
  • the chip includes: a processor, configured to call and run a computer program from the memory, so that the device installed with the chip executes any one of the above-mentioned first to second aspects or any of the implementations thereof. method.
  • a computer-readable storage medium for storing a computer program, and the computer program causes a computer to execute any one of the above-mentioned first to second aspects or the method in each implementation manner thereof.
  • a computer program product including computer program instructions, the computer program instructions cause a computer to execute any one of the above first to second aspects or the method in each implementation manner.
  • a computer program which, when running on a computer, causes the computer to execute any one of the above-mentioned first to second aspects or the method in each implementation manner thereof.
  • a code stream is provided, where the code stream is generated by any one of the first aspects above or each implementation thereof.
  • the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are determined by decoding the code stream; the weighted fusion condition of the current block is determined according to the image content of the current sequence, and the weighted fusion condition is used to judge the current Whether the block is weighted and predicted by the first intra-frame prediction mode and the second intra-frame prediction mode; according to the weighted fusion condition, and at least one of the first intra-frame prediction mode and the second intra-frame prediction mode, determine the target prediction of the current block value.
  • the present application determines the weighted fusion condition of the current block according to the image content of the current sequence, and judges whether to perform weighted fusion prediction on the current block based on the weighted fusion condition, which can avoid the time when weighted fusion prediction is performed on image content that does not need weighted fusion prediction. , reduce the quality of prediction, introduce unnecessary noise problems, and then improve the accuracy of intra prediction.
  • FIG. 1 is a schematic block diagram of a video encoding and decoding system involved in an embodiment of the present application
  • Fig. 2 is a schematic block diagram of a video encoder involved in an embodiment of the present application
  • Fig. 3 is a schematic block diagram of a video decoder involved in an embodiment of the present application.
  • FIG. 4 is a schematic diagram of an intra prediction mode
  • FIG. 5 is a schematic diagram of an intra prediction mode
  • FIG. 6 is a schematic diagram of an intra prediction mode
  • Figure 7 is a schematic diagram of the prediction of TIMD
  • FIG. 8 is a schematic flowchart of an intra prediction method provided by an embodiment of the present application.
  • FIG. 9 is a schematic flowchart of an intra prediction method provided by an embodiment of the present application.
  • FIG. 10 is a schematic flowchart of an intra prediction method provided by an embodiment of the present application.
  • FIG. 11 is a schematic flowchart of an intra prediction method provided by an embodiment of the present application.
  • Fig. 12 is a schematic block diagram of an intra prediction device provided by an embodiment of the present application.
  • Fig. 13 is a schematic block diagram of an intra prediction device provided by an embodiment of the present application.
  • Fig. 14 is a schematic block diagram of an electronic device provided by an embodiment of the present application.
  • Fig. 15 is a schematic block diagram of a video codec system provided by an embodiment of the present application.
  • the application can be applied to the field of image codec, video codec, hardware video codec, dedicated circuit video codec, real-time video codec, etc.
  • the solution of the present application can be combined with audio and video coding standards (audio video coding standard, referred to as AVS), for example, H.264/audio video coding (audio video coding, referred to as AVC) standard, H.265/high efficiency video coding ( High efficiency video coding (HEVC for short) standard and H.266/versatile video coding (VVC for short) standard.
  • the solutions of the present application may operate in conjunction with other proprietary or industry standards, including ITU-TH.261, ISO/IECMPEG-1Visual, ITU-TH.262 or ISO/IECMPEG-2Visual, ITU-TH.263 , ISO/IECMPEG-4Visual, ITU-TH.264 (also known as ISO/IECMPEG-4AVC), including scalable video codec (SVC) and multi-view video codec (MVC) extensions.
  • SVC scalable video codec
  • MVC multi-view video codec
  • FIG. 1 is a schematic block diagram of a video encoding and decoding system involved in an embodiment of the present application. It should be noted that FIG. 1 is only an example, and the video codec system in the embodiment of the present application includes but is not limited to what is shown in FIG. 1 .
  • the video codec system 100 includes an encoding device 110 and a decoding device 120 .
  • the encoding device is used to encode (can be understood as compression) the video data to generate a code stream, and transmit the code stream to the decoding device.
  • the decoding device decodes the code stream generated by the encoding device to obtain decoded video data.
  • the encoding device 110 in the embodiment of the present application can be understood as a device having a video encoding function
  • the decoding device 120 can be understood as a device having a video decoding function, that is, the embodiment of the present application includes a wider range of devices for the encoding device 110 and the decoding device 120, Examples include smartphones, desktop computers, mobile computing devices, notebook (eg, laptop) computers, tablet computers, set-top boxes, televisions, cameras, display devices, digital media players, video game consoles, vehicle-mounted computers, and the like.
  • the encoding device 110 may transmit the encoded video data (such as code stream) to the decoding device 120 via the channel 130 .
  • Channel 130 may include one or more media and/or devices capable of transmitting encoded video data from encoding device 110 to decoding device 120 .
  • channel 130 includes one or more communication media that enable encoding device 110 to transmit encoded video data directly to decoding device 120 in real-time.
  • encoding device 110 may modulate the encoded video data according to a communication standard and transmit the modulated video data to decoding device 120 .
  • the communication medium includes a wireless communication medium, such as a radio frequency spectrum.
  • the communication medium may also include a wired communication medium, such as one or more physical transmission lines.
  • the channel 130 includes a storage medium that can store video data encoded by the encoding device 110 .
  • the storage medium includes a variety of local access data storage media, such as optical discs, DVDs, flash memory, and the like.
  • the decoding device 120 may acquire encoded video data from the storage medium.
  • channel 130 may include a storage server that may store video data encoded by encoding device 110 .
  • the decoding device 120 may download the stored encoded video data from the storage server.
  • the storage server may store the encoded video data and may transmit the encoded video data to the decoding device 120, such as a web server (eg, for a website), a file transfer protocol (FTP) server, and the like.
  • FTP file transfer protocol
  • the encoding device 110 includes a video encoder 112 and an output interface 113 .
  • the output interface 113 may include a modulator/demodulator (modem) and/or a transmitter.
  • the encoding device 110 may include a video source 111 in addition to the video encoder 112 and the input interface 113 .
  • the video source 111 may include at least one of a video capture device (for example, a video camera), a video archive, a video input interface, a computer graphics system, wherein the video input interface is used to receive video data from a video content provider, and the computer graphics system Used to generate video data.
  • a video capture device for example, a video camera
  • a video archive for example, a video archive
  • a video input interface for example, a video archive
  • video input interface for example, a video input interface
  • computer graphics system used to generate video data.
  • the video encoder 112 encodes the video data from the video source 111 to generate a code stream.
  • Video data may include one or more pictures or a sequence of pictures.
  • the code stream contains the encoding information of an image or image sequence in the form of a bit stream.
  • Encoding information may include encoded image data and associated data.
  • the associated data may include a sequence parameter set (SPS for short), a picture parameter set (PPS for short) and other syntax structures.
  • SPS sequence parameter set
  • PPS picture parameter set
  • An SPS may contain parameters that apply to one or more sequences.
  • a PPS may contain parameters applied to one or more images.
  • the syntax structure refers to a set of zero or more syntax elements arranged in a specified order in the code stream.
  • the video encoder 112 directly transmits encoded video data to the decoding device 120 via the output interface 113 .
  • the encoded video data can also be stored on a storage medium or a storage server for subsequent reading by the decoding device 120 .
  • the decoding device 120 includes an input interface 121 and a video decoder 122 .
  • the decoding device 120 may include a display device 123 in addition to the input interface 121 and the video decoder 122 .
  • the input interface 121 includes a receiver and/or a modem.
  • the input interface 121 can receive encoded video data through the channel 130 .
  • the video decoder 122 is used to decode the encoded video data to obtain decoded video data, and transmit the decoded video data to the display device 123 .
  • the display device 123 displays the decoded video data.
  • the display device 123 may be integrated with the decoding device 120 or external to the decoding device 120 .
  • the display device 123 may include various display devices, such as a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or other types of display devices.
  • LCD liquid crystal display
  • plasma display a plasma display
  • OLED organic light emitting diode
  • FIG. 1 is only an example, and the technical solutions of the embodiments of the present application are not limited to FIG. 1 .
  • the technology of the present application may also be applied to one-sided video encoding or one-sided video decoding.
  • Fig. 2 is a schematic block diagram of a video encoder involved in an embodiment of the present application. It should be understood that the video encoder 200 can be used to perform lossy compression on images, and can also be used to perform lossless compression on images.
  • the lossless compression may be visually lossless compression or mathematically lossless compression.
  • the video encoder 200 can be applied to image data in luminance-chrominance (YCbCr, YUV) format.
  • the YUV ratio can be 4:2:0, 4:2:2 or 4:4:4, Y means brightness (Luma), Cb (U) means blue chroma, Cr (V) means red chroma, U and V are expressed as chroma (Chroma) for describing color and saturation.
  • 4:2:0 means that every 4 pixels have 4 luminance components
  • 2 chroma components YYYYCbCr
  • 4:2:2 means that every 4 pixels have 4 luminance components
  • 4 Chroma component YYYYCbCrCbCr
  • 4:4:4 means full pixel display (YYYYCbCrCbCrCbCrCbCr).
  • the video encoder 200 reads video data, and divides a frame of image into several coding tree units (coding tree units, CTUs) for each frame of image in the video data.
  • CTB can be called “Tree block", “Largest Coding unit” (LCU for short) or “coding tree block” (CTB for short).
  • LCU Large Coding unit
  • CTB coding tree block
  • Each CTU may be associated with a pixel block of equal size within the image. Each pixel may correspond to one luminance (luma) sample and two chrominance (chrominance or chroma) samples.
  • each CTU may be associated with one block of luma samples and two blocks of chroma samples.
  • a CTU size is, for example, 128 ⁇ 128, 64 ⁇ 64, 32 ⁇ 32 and so on.
  • a CTU can be further divided into several coding units (Coding Unit, CU) for coding, and the CU can be a rectangular block or a square block.
  • the CU can be further divided into a prediction unit (PU for short) and a transform unit (TU for short), so that encoding, prediction, and transformation are separated, and processing is more flexible.
  • a CTU is divided into CUs in a quadtree manner, and a CU is divided into TUs and PUs in a quadtree manner.
  • the video encoder and video decoder can support various PU sizes. Assuming that the size of a specific CU is 2N ⁇ 2N, video encoders and video decoders may support 2N ⁇ 2N or N ⁇ N PU sizes for intra prediction, and support 2N ⁇ 2N, 2N ⁇ N, N ⁇ 2N, NxN or similarly sized symmetric PUs for inter prediction. The video encoder and video decoder may also support asymmetric PUs of 2NxnU, 2NxnD, nLx2N, and nRx2N for inter prediction.
  • the video encoder 200 may include: a prediction unit 210, a residual unit 220, a transform/quantization unit 230, an inverse transform/quantization unit 240, a reconstruction unit 250, and a loop filter unit 260. Decoded image cache 270 and entropy coding unit 280. It should be noted that the video encoder 200 may include more, less or different functional components.
  • the current block may be called a current coding unit (CU) or a current prediction unit (PU).
  • a predicted block may also be called a predicted image block or an image predicted block, and a reconstructed image block may also be called a reconstructed block or an image reconstructed image block.
  • the prediction unit 210 includes an inter prediction unit 211 and an intra estimation unit 212 . Because there is a strong correlation between adjacent pixels in a video frame, the intra-frame prediction method is used in video coding and decoding technology to eliminate the spatial redundancy between adjacent pixels. Due to the strong similarity between adjacent frames in video, the inter-frame prediction method is used in video coding and decoding technology to eliminate time redundancy between adjacent frames, thereby improving coding efficiency.
  • the inter-frame prediction unit 211 can be used for inter-frame prediction.
  • the inter-frame prediction can refer to image information of different frames.
  • the inter-frame prediction uses motion information to find a reference block from the reference frame, and generates a prediction block according to the reference block to eliminate temporal redundancy;
  • Frames used for inter-frame prediction may be P frames and/or B frames, P frames refer to forward predictive frames, and B frames refer to bidirectional predictive frames.
  • the motion information includes the reference frame list where the reference frame is located, the reference frame index, and the motion vector.
  • the motion vector can be an integer pixel or a sub-pixel. If the motion vector is sub-pixel, then it is necessary to use interpolation filtering in the reference frame to make the required sub-pixel block.
  • the reference frame found according to the motion vector A block of whole pixels or sub-pixels is called a reference block.
  • Some technologies will directly use the reference block as a prediction block, and some technologies will further process the reference block to generate a prediction block. Reprocessing and generating a prediction block based on a reference block can also be understood as taking the reference block as a prediction block and then processing and generating a new prediction block based on the prediction block.
  • the intra-frame estimation unit 212 only refers to the information of the same frame of images to predict the pixel information in the current code image block for eliminating spatial redundancy.
  • a frame used for intra prediction may be an I frame.
  • the pixels in the left row and the upper column of the current block are reference pixels of the current block, and the intra prediction uses these reference pixels to predict the current block.
  • These reference pixels may all be available, that is, all have been encoded and decoded. Some parts may also be unavailable, for example, the current block is the leftmost of the whole frame, then the reference pixel on the left of the current block is unavailable.
  • the lower left part of the current block has not been encoded and decoded, so the reference pixel at the lower left is also unavailable.
  • the available reference pixel or some value or some method can be used for filling, or no filling is performed.
  • FIG. 4 is a schematic diagram of intra-frame prediction modes.
  • the intra-frame prediction modes used by HEVC include Planar, DC, and 33 angle modes, a total of 35 prediction modes.
  • Fig. 5 is a schematic diagram of an intra-frame prediction mode.
  • the intra-frame modes used by VVC include Planar, DC and 65 angle modes, a total of 67 prediction modes.
  • Figure 6 is a schematic diagram of the intra prediction mode. As shown in Figure 6, AVS3 uses DC, Planar, Bilinear and 63 angle modes, a total of 66 prediction modes
  • the intra-frame prediction will be more accurate, and it will be more in line with the demand for the development of high-definition and ultra-high-definition digital video.
  • the residual unit 220 may generate a residual block of the CU based on the pixel blocks of the CU and the prediction blocks of the PUs of the CU. For example, residual unit 220 may generate a residual block for a CU such that each sample in the residual block has a value equal to the difference between the samples in the pixel blocks of the CU, and the samples in the PUs of the CU. Corresponding samples in the predicted block.
  • Transform/quantization unit 230 may quantize the transform coefficients. Transform/quantization unit 230 may quantize transform coefficients associated with TUs of a CU based on quantization parameter (QP) values associated with the CU. Video encoder 200 may adjust the degree of quantization applied to transform coefficients associated with a CU by adjusting the QP value associated with the CU.
  • QP quantization parameter
  • Inverse transform/quantization unit 240 may apply inverse quantization and inverse transform to the quantized transform coefficients, respectively, to reconstruct a residual block from the quantized transform coefficients.
  • the reconstruction unit 250 may add samples of the reconstructed residual block to corresponding samples of one or more prediction blocks generated by the prediction unit 210 to generate a reconstructed image block associated with the TU. By reconstructing the sample blocks of each TU of the CU in this way, the video encoder 200 can reconstruct the pixel blocks of the CU.
  • Loop filtering unit 260 may perform deblocking filtering operations to reduce blocking artifacts of pixel blocks associated with a CU.
  • the loop filtering unit 260 includes a deblocking filtering unit and a sample adaptive compensation/adaptive loop filtering (SAO/ALF) unit, wherein the deblocking filtering unit is used for deblocking, and the SAO/ALF unit Used to remove ringing effects.
  • SAO/ALF sample adaptive compensation/adaptive loop filtering
  • the decoded image buffer 270 may store reconstructed pixel blocks.
  • Inter prediction unit 211 may use reference pictures containing reconstructed pixel blocks to perform inter prediction on PUs of other pictures.
  • intra estimation unit 212 may use the reconstructed pixel blocks in decoded picture cache 270 to perform intra prediction on other PUs in the same picture as the CU.
  • Entropy encoding unit 280 may receive the quantized transform coefficients from transform/quantization unit 230 . Entropy encoding unit 280 may perform one or more entropy encoding operations on the quantized transform coefficients to generate entropy encoded data.
  • Fig. 3 is a schematic block diagram of a video decoder involved in an embodiment of the present application.
  • the video decoder 300 includes: an entropy decoding unit 310 , a prediction unit 320 , an inverse quantization/transformation unit 330 , a reconstruction unit 340 , a loop filter unit 350 and a decoded image buffer 360 . It should be noted that the video decoder 300 may include more, less or different functional components.
  • the video decoder 300 can receive code streams.
  • the entropy decoding unit 310 may parse the codestream to extract syntax elements from the codestream. As part of parsing the codestream, the entropy decoding unit 310 may parse the entropy-encoded syntax elements in the codestream.
  • the prediction unit 320 , the inverse quantization/transformation unit 330 , the reconstruction unit 340 and the loop filter unit 350 can decode video data according to the syntax elements extracted from the code stream, that is, generate decoded video data.
  • the prediction unit 320 includes an inter prediction unit 321 and an intra estimation unit 322 .
  • Intra estimation unit 322 may perform intra prediction to generate a predictive block for a PU.
  • Intra-estimation unit 322 may use an intra-prediction mode to generate a predictive block for a PU based on pixel blocks of spatially neighboring PUs.
  • Intra estimation unit 322 may also determine the intra prediction mode for the PU from one or more syntax elements parsed from the codestream.
  • the inter prediction unit 321 can construct the first reference picture list (list 0) and the second reference picture list (list 1) according to the syntax elements parsed from the codestream. Furthermore, if the PU is encoded using inter prediction, entropy decoding unit 310 may parse the motion information for the PU. Inter prediction unit 321 may determine one or more reference blocks for the PU according to the motion information of the PU. Inter prediction unit 321 may generate a prediction block for a PU based on one or more reference blocks of the PU.
  • Inverse quantization/transform unit 330 may inversely quantize (ie, dequantize) the transform coefficients associated with a TU. Inverse quantization/transform unit 330 may use QP values associated with CUs of the TU to determine the degree of quantization.
  • inverse quantization/transform unit 330 may apply one or more inverse transforms to the inverse quantized transform coefficients in order to generate a residual block associated with the TU.
  • Reconstruction unit 340 uses the residual blocks associated with the TUs of the CU and the prediction blocks of the PUs of the CU to reconstruct the pixel blocks of the CU. For example, the reconstruction unit 340 may add the samples of the residual block to the corresponding samples of the prediction block to reconstruct the pixel block of the CU to obtain the reconstructed image block.
  • Loop filtering unit 350 may perform deblocking filtering operations to reduce blocking artifacts of pixel blocks associated with a CU.
  • Video decoder 300 may store the reconstructed picture of the CU in decoded picture cache 360 .
  • the video decoder 300 may use the reconstructed picture in the decoded picture buffer 360 as a reference picture for subsequent prediction, or transmit the reconstructed picture to a display device for presentation.
  • the basic flow of video encoding and decoding is as follows: at the encoding end, a frame of image is divided into blocks, and for the current block, the prediction unit 210 uses intra-frame prediction or inter-frame prediction to generate the prediction block of the current block .
  • the residual unit 220 may calculate a residual block based on the predicted block and the original block of the current block, for example, subtract the predicted block from the original block of the current block to obtain a residual block, which may also be referred to as residual information.
  • the residual block can be transformed and quantized by the transformation/quantization unit 230 to remove information that is not sensitive to human eyes, so as to eliminate visual redundancy.
  • the residual block before being transformed and quantized by the transform/quantization unit 230 may be called a time domain residual block, and the time domain residual block after being transformed and quantized by the transform/quantization unit 230 may be called a frequency residual block or a frequency-domain residual block.
  • the entropy encoding unit 280 receives the quantized transform coefficients output by the transform and quantization unit 230 , may perform entropy encoding on the quantized transform coefficients, and output a code stream.
  • the entropy coding unit 280 can eliminate character redundancy according to the target context model and the probability information of the binary code stream.
  • the entropy decoding unit 310 can analyze the code stream to obtain the prediction information of the current block, the quantization coefficient matrix, etc., and the prediction unit 320 uses intra prediction or inter prediction for the current block based on the prediction information to generate a prediction block of the current block.
  • the inverse quantization/transformation unit 330 uses the quantization coefficient matrix obtained from the code stream to perform inverse quantization and inverse transformation on the quantization coefficient matrix to obtain a residual block.
  • the reconstruction unit 340 adds the predicted block and the residual block to obtain a reconstructed block.
  • the reconstructed blocks form a reconstructed image, and the loop filtering unit 350 performs loop filtering on the reconstructed image based on the image or based on the block to obtain a decoded image.
  • the encoding end also needs similar operations to the decoding end to obtain the decoded image.
  • the decoded image may also be referred to as a reconstructed image, and the reconstructed image may be a subsequent frame as a reference frame for inter-frame prediction.
  • the block division information determined by the encoder as well as mode information or parameter information such as prediction, transformation, quantization, entropy coding, and loop filtering, etc., are carried in the code stream when necessary.
  • the decoding end analyzes the code stream and analyzes the existing information to determine the same block division information as the encoding end, prediction, transformation, quantization, entropy coding, loop filtering and other mode information or parameter information, so as to ensure the decoding image obtained by the encoding end It is the same as the decoded image obtained by the decoder.
  • the current block may be the current coding unit (CU) or the current prediction unit (PU).
  • the above is the basic process of the video codec under the block-based hybrid coding framework. With the development of technology, some modules or steps of the framework or process may be optimized. This application is applicable to the block-based hybrid coding framework.
  • the basic process of the video codec but not limited to the framework and process.
  • the general hybrid encoding framework will first perform prediction, and the prediction uses the spatial or temporal correlation performance to obtain an image that is the same as or similar to the current block.
  • the prediction uses the spatial or temporal correlation performance to obtain an image that is the same as or similar to the current block.
  • the hybrid coding framework will subtract the predicted image from the original image of the current block to obtain a residual image, or subtract the predicted block from the current block to obtain a residual block.
  • Residual blocks are usually much simpler than the original image, so prediction can significantly improve compression efficiency.
  • the residual block is not directly encoded, but usually transformed first.
  • the transformation is to transform the residual image from the spatial domain to the frequency domain, and remove the correlation of the residual image.
  • After the residual image is transformed into the frequency domain since most of the energy is concentrated in the low-frequency region, most of the transformed non-zero coefficients are concentrated in the upper left corner.
  • quantization is used for further compression. And because the human eye is not sensitive to high frequencies, a larger quantization step size can be used in high frequency areas.
  • JVET an international video coding standard-setting organization
  • the model that is, the platform test software, the Enhanced Compression Model (ECM for short).
  • ECM Enhanced Compression Model
  • ECM is a reference software for further improving the performance of VVC tools and the combination of tools. It is based on VTM-10.0 and integrates tools and technologies adopted by EE.
  • VTM VVC's reference software test platform
  • intra-frame prediction Similar to VTM (VVC's reference software test platform), there are traditional intra-frame prediction, residual transformation and other processes.
  • the difference from VVC is that in the intra-frame prediction process, two techniques for deriving the intra-frame prediction mode are adopted, namely Decoder-side Intra Mode Derivation (DIMD) and template-based frame Inner mode export (Template-based Intra Mode Derivation, TIMD).
  • DIMD Decoder-side Intra Mode Derivation
  • TIMD template-based frame Inner mode export
  • the TIMD and DIMD technologies can derive the intra-frame prediction mode at the decoding end, thereby saving the index of the coding intra-frame prediction mode, so as to save codewords.
  • TIMD utilizes the method of deriving the prediction mode at the codec side to save the transmission mode index overhead, and at the same time uses the fusion method to improve the prediction block quality of the intra prediction.
  • the TIMD technology in ECM2.0 can be understood as two main parts. First, the cost information of the original intra prediction angle mode and non-angle mode is calculated according to the template. The prediction mode corresponding to the minimum cost and the second minimum cost will be selected, and the minimum cost The corresponding prediction mode is recorded as mode 1 (denoted as mode1), and the prediction mode corresponding to the next smallest cost is recorded as mode 2 (denoted as mode2).
  • the original intra prediction angle mode is designed to be obtained from the MPM list in the existing ECM, which has achieved the effect of reducing complexity.
  • TIMD derives the Most Probable Mode (MPM for short) list through the intra prediction modes selected by the five blocks above, left, upper left, lower left, and upper right of the current block.
  • MPM Most Probable Mode
  • the reconstruction value in the reference template reference of the template
  • the prediction results are made for the template (template) area respectively.
  • SATD Sum of absolute transformed differences
  • the TIMD does not perform the fusion operation, and only uses the prediction block obtained by mode1 as the prediction block of the current coding unit.
  • TIMD fusion technology will further refine the prediction mode. If mode1 is an angle mode, then use mode1 as the central prediction direction, and shift to the left and right by a certain angle to obtain mode1 + and mode1 - . If mode1 + and mode - If the cost information is smaller than mode1, replace mode1 as the updated optimal prediction mode; similarly, refine mode2.
  • the prediction blocks corresponding to mode1 and mode2 are weighted and fused according to the preset weight, and the preset weight is calculated according to the cost information.
  • weights corresponding to model1 and model2 are determined according to the following formulas (1) and (2):
  • the predicted value of the current block is determined according to the following formula (3):
  • Pred Pred mode1 ⁇ w1+Pred mode2 ⁇ w2 (3)
  • weight1 is the weighted weight corresponding to the predicted value of mode1
  • weight2 is the weighted weight of the predicted value corresponding to mode2
  • Pred mode1 is the predicted block corresponding to mode1
  • Pred mode2 is the predicted value corresponding to mode2
  • Pred is the predicted value of TIMD.
  • the TIMD technology selects the planar mode for prediction without weighted fusion.
  • TIMD needs to transmit a flag bit to the decoder to indicate whether the current coding unit uses TIMD technology.
  • the prediction mode derivation of the TIMD technology can reduce the transmission burden of certain syntax elements, so that the prediction mode overhead that originally required at least 5 bits or more is reduced to 1 bit.
  • TIMD after TIMD obtains the prediction mode information, it fuses the prediction values of the optimal prediction mode and the suboptimal prediction mode through a fusion operation to generate a new prediction value.
  • the new forecast value is neither predictable by any of the aforementioned forecast modes, nor can the same forecast value be obtained in subsequent forecast tools. Through experimental comparison, it can be found that the fusion technology does improve the prediction efficiency.
  • the prediction value obtained by weighted fusion is suitable for video content in natural scenes, but not for video content in specific scenes.
  • Objects in the former video content usually have blurred edges and some noise generated by shooting, and TIMD’s fusion technology can obtain prediction values that better match these objects.
  • the objects in the latter video content generally have sharper and brighter colors.
  • These video contents are usually recorded by computers or called screen content videos.
  • the prediction value generated by TIMD’s fusion technology is redundant in such content. It reduces the quality of prediction and can be said to bring noise.
  • the fusion technology using TIMD not only fails to improve the compression efficiency, but reduces the prediction quality and introduces unnecessary noise.
  • the present application determines the weighted fusion conditions according to the image content of the current sequence, that is to say, the weighted fusion conditions corresponding to different image contents can be different, so according to the weighted fusion conditions corresponding to the image content of the current sequence, to Judging whether to perform weighted fusion prediction on the current block can avoid the problems of reducing prediction quality and introducing unnecessary noise when weighted fusion prediction is performed on image content that does not require weighted fusion prediction, thereby improving the accuracy of intra prediction.
  • the intra prediction method provided by the embodiment of the present application can be applied to any scene where two or more intra prediction modes are allowed to perform weighted fusion prediction in addition to the above-mentioned TIMD technology.
  • the video decoding method provided in the embodiment of the present application is introduced by taking the decoding end as an example.
  • FIG. 8 is a schematic flowchart of an intra prediction method provided by an embodiment of the present application.
  • the embodiment of the present application is applied to the video decoder shown in FIG. 1 and FIG. 2 .
  • the method of the embodiment of the present application includes:
  • S401 Decode a code stream, and determine a first intra-frame prediction mode and a second intra-frame prediction mode of a current block.
  • the current block may also be referred to as a current decoding block, a current decoding unit, a decoding block, a block to be decoded, a current block to be decoded, and the like.
  • the current block when the current block includes a chroma component but does not include a luma component, the current block may be called a chroma block.
  • the current block when the current block includes a luma component but does not include a chroma component, the current block may be called a luma block.
  • the video decoder determines the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition
  • use the first intra-frame prediction mode to predict the current block, obtain the first prediction value of the current block, and use the second frame
  • the intra prediction mode predicts the current block to obtain the second prediction value of the current block, and performs weighted fusion of the first prediction value and the second prediction value to obtain the target prediction value of the current block.
  • one of the first intra-frame prediction mode and the second intra-frame prediction mode is used. , to predict the current block to obtain the target prediction value of the current block.
  • the method for the video decoder to determine that the current block allows two intra-frame prediction modes to perform fusion weighted prediction may be: the video encoder carries a second flag in the code stream, and the second flag is used to indicate that the current block Whether to determine the target predictive value through at least one of the first intra-frame prediction mode and the second intra-frame prediction mode. If the video encoder uses at least one of the first intra-frame prediction mode and the second intra-frame prediction mode to determine the target prediction value, set the second flag to true, for example, set the value of the second flag to 1, and set The second flag set to true is written into the code stream, for example, into the code stream header.
  • the video decoder After the video decoder obtains the code stream, it decodes the code stream to obtain the second flag. If the second flag is true, for example, the value of the second flag is 1, the video decoder determines that the current block passes through the first frame. At least one of the intra prediction mode and the second intra prediction mode determines a target prediction value, and at this time, the video decoder determines the first intra prediction mode and the second intra prediction mode of the current block. Optionally, the video decoder determines the first intra-frame prediction mode and the second intra-frame prediction mode in the same manner as the video encoder determines the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the video encoder does not determine the target predictive value of the current block through at least one of the first intra-frame prediction mode and the second intra-frame prediction mode, set the second flag to false, for example, set the value of the second flag to is 0, and writes the false second flag into the code stream, for example, into the code stream header.
  • the video decoder decodes the code stream to obtain the second flag. If the second flag is false, for example, the value of the second flag is 0, the video decoder is not sure about the first intra-frame prediction mode and the second frame of the current block. Instead, it traverses the preset intra prediction modes, determines the intra prediction mode with the least cost to predict the current block, and obtains the target prediction value of the current block.
  • the embodiment of the present application mainly involves that the target prediction value of the current block is determined by at least one of the first intra-frame prediction mode and the second intra-frame prediction mode, that is to say, the present application mainly discusses the above-mentioned The second flag is true.
  • the above-mentioned second flag may be a TIMD enable flag, for example, sps_timd_enable_flag. That is to say, in the embodiment of the present application, the video decoder decodes the code stream to obtain the use-allowed flag bit of the TIMD, and the use-allowed flag bit of the TIMD is a sequence-level flag bit.
  • the allowed flag bit of the TIMD is used to indicate whether the current sequence is allowed to use the TIMD technology. If the allowed flag bit of TIMD is true, for example, 1, it is determined that the current sequence is allowed to use the TIMD technology.
  • the video decoder continues to decode the code stream to obtain a TIMD enable flag, which may be a sequence-level flag.
  • the TIMD enabling flag is used to indicate whether the current block uses the TIMD technology. If the TIMD enabling flag is true, for example, 1, it is determined that the current block uses the TIMD technology. At this time, the video decoder determines the first intra prediction of the current block mode and a second intra prediction mode.
  • the above-mentioned TIMD enabling flag may also be an image-level sequence, which is used to indicate whether the current frame image uses the TIMD technology.
  • the true or false of the TIMD enable flag is determined by the video encoder and written into the code stream. For example, when the video encoder uses TIMD technology to determine the target prediction value of the current block, the TIMD enable flag is set to If it is true, for example, it is set to 1, and the code stream is written, for example, the code stream header is written. If the video encoder does not use TIMD technology to determine the target prediction value of the current block, then set the TIMD enable flag to false, for example, to 0, and write the code stream, for example, into the code stream header.
  • the video decoder can parse out the TIMD enable flag from the code stream, and determine whether to use TIMD technology to determine the target prediction value of the current block according to the TIMD enable flag, so as to ensure the consistency between the decoding end and the encoding end, and ensure the reliability of prediction sex.
  • the video decoder determines that at least one of the first intra-frame prediction mode and the second intra-frame prediction mode needs to be used to determine the target prediction value of the current block, perform the above S401 to determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block. Intra prediction mode.
  • the ways of determining the first intra-frame prediction mode and the second intra-frame prediction mode of the current block in S401 above include but are not limited to the following:
  • Method 1 traverse the preset intra prediction list, select the intra prediction mode with the lowest cost as the first intra prediction mode, and select the next smallest intra prediction mode as the second intra prediction mode.
  • the aforementioned preset intra-frame prediction list may include any one of intra-frame coding modes such as Direct Current (DC) mode, planar (PLANAR) mode, and angle mode.
  • DC Direct Current
  • PLANAR planar
  • angle mode angle mode
  • the video decoder traverses different intra prediction modes in the preset intra prediction list to perform predictive encoding on the current block, and then calculates the cost corresponding to each prediction mode in the multiple prediction modes.
  • the intra-frame prediction mode corresponding to the minimum cost is determined as the first intra-frame prediction mode of the current block, and the intra-frame prediction mode corresponding to the next smallest cost is determined as the second intra-frame prediction mode of the current block.
  • the costs corresponding to the foregoing prediction modes may be SAD or SATD as the approximate cost of each prediction mode.
  • the current block and the predicted value of the current block may be used to determine SAD and SATD.
  • a certain intra prediction mode is used to predict the current block to obtain a predicted value of the current block, and the pixel difference between the current block and the predicted value of the current block is determined as the SAD corresponding to the intra prediction mode.
  • the current block is subtracted from the predicted value of the current block to obtain the residual value of the current block, and the residual value is subjected to Hadamard transformation, and then the sum of the absolute values of each element is calculated, and then the SATD corresponding to the intra prediction mode is obtained.
  • Way 2 Determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block according to the MPM of the current block. That is, the above S401 includes the following steps of S401-A1 and S401-A2:
  • S401-A2 Determine a first intra-frame prediction mode and a second intra-frame prediction mode according to the most probable mode.
  • the most probable mode list (MostprobableModes List, MPM) intra-mode encoding technology can be used to improve the encoding and decoding efficiency.
  • MPM most probable mode list
  • intra-frame prediction mode of the surrounding encoded and decoded blocks and the intra-frame prediction mode derived from the intra-frame prediction mode of the surrounding encoded and decoded blocks, such as adjacent modes, and some intra-frame predictions that are commonly used or have a relatively high probability of use Modes, such as DC, Planar, Bilinear mode, etc., constitute a mode list.
  • Intra prediction modes that refer to surrounding coded blocks take advantage of spatial correlation. Because the texture will have a certain continuity in space, MPM can be used as an intra prediction mode for prediction. That is to say, the probability that the current block uses MPM is higher than that of not using MPM. Therefore, during binarization, fewer codewords will be used for MPM, thereby saving overhead and improving encoding and decoding efficiency.
  • the MPM is composed according to the intra prediction mode of the decoded area around the current block, so that the video decoder obtains the intra prediction mode used by the image blocks in the decoded area around the current block, and then forms the MPM of the current block .
  • the MPM of the current block is formed by using the intra-frame prediction modes of the upper, upper left, and upper right regions of the current block.
  • the intra prediction mode of the decoded area in the upper right area, upper area, upper left area, left area, and lower left area of the current block The MPM that makes up the current block.
  • the upper right area uses intra prediction mode 1 when decoding
  • the upper area uses intra prediction mode 2 when decoding
  • the upper left area uses intra prediction mode 3 when decoding
  • the left area uses frame when decoding
  • Intra prediction mode 2 intra prediction mode 4 used in decoding the lower left area, so that it can be determined that the MPM of the current block includes intra prediction mode 1, intra prediction mode 2, intra prediction mode 3 and intra prediction mode 4.
  • the intra prediction mode corresponding to the decoded area in these areas is used to construct the current block. MPM.
  • the current block is the first block to be decoded, that is to say, there is no decoded area around the current block, at this time, several intra prediction modes can be selected from the preset intra prediction modes to construct The MPM of the current block.
  • the current block is the first block to be decoded
  • the first intra-frame prediction mode and the second intra-frame prediction mode are determined according to the MPM.
  • the intra prediction modes in the MPM are recorded as candidate intra prediction modes.
  • the manner of determining the first intra-frame prediction mode and the second intra-frame prediction mode includes but not limited to the following examples:
  • Example 1 Determine a candidate intra-frame prediction mode in the above MPM as the first intra-frame prediction mode, and determine a candidate intra-frame prediction mode in the MPM other than the first intra-frame prediction mode as the second intra-frame prediction mode predictive mode. For example, any candidate intra prediction mode in the MPM is determined as the first intra prediction mode, and any candidate preset mode in the MPM except the first intra prediction mode is determined as the second intra prediction mode.
  • Example 2 determine the cost when using the candidate intra prediction mode in the MPM to predict the current block; determine the first intra prediction mode and the second intra prediction mode according to the cost corresponding to the candidate intra prediction mode in the MPM model. For example, each candidate intra prediction mode in the MPM is used to predictively encode the current block, and the cost corresponding to each candidate intra prediction mode is obtained. Next, according to the cost corresponding to each candidate intra prediction mode in the MPM, determine the first intra prediction mode and the second intra prediction mode, for example, determine the candidate intra prediction mode with the smallest cost in the MPM as the first intra prediction mode The prediction mode is to determine the candidate intra-frame prediction mode with the second lowest cost in the MPM as the second intra-frame prediction mode.
  • the foregoing cost may be SAD or SATD, etc., which is not limited in this application.
  • the first intra prediction mode and the second intra prediction mode of the current block are determined by determining the MPM of the current block and the cost of predictive encoding of the current block according to each candidate intra prediction mode in the MPM, Since there are fewer intra-frame prediction modes included in the MPM, the complexity of determining the first intra-frame prediction mode and the second intra-frame prediction mode is reduced, and the accuracy of the first intra-frame prediction mode and the second intra-frame prediction mode is improved. Determine the speed to improve forecasting efficiency.
  • the present application adopts the TIMD technology, the following method 3 is adopted to determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block.
  • TIMD enable flag indicates that the current block uses TIMD technology, determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block.
  • the TIMD technology derives the intra-frame prediction mode based on templates. Based on this, after the video decoder obtains the code stream, it decodes the code stream to obtain the TIMD enable flag. If the TIMD enable flag is true, for example, the TIMD enable If the value of the enable flag is 1, it is determined that the current block uses the TIMD technology to determine the target prediction value of the current block. At this time, the first intra-frame prediction mode and the second intra-frame prediction mode of the current block may be determined by performing predictive encoding on the template of the current block shown in FIG. 7 , instead of directly performing predictive encoding on the current block to determine the second An intra prediction mode and a second intra prediction mode.
  • the effect of the intra-frame prediction mode can be determined according to the difference between the predicted value of the template and the reconstructed value, and then the first intra-frame prediction mode of the current block can be determined accurately and quickly and a second intra prediction mode.
  • the manners of determining the first intra-frame prediction mode and the second intra-frame prediction mode of the current block in S401-B2 above include but are not limited to the following examples:
  • Example 1 traversing the preset intra-frame prediction mode list, using each intra-frame prediction mode in the intra-frame prediction mode list to perform predictive encoding on the template of the current block, and obtaining the prediction value corresponding to each prediction mode.
  • compare the prediction value corresponding to each prediction mode with the reconstruction value of the template for example, calculate the cost between the prediction value corresponding to the prediction mode and the reconstruction value of the template, such as SAD or SATD, and determine the prediction mode with the smallest cost As the first intra-frame prediction mode of the current block, the prediction mode with the second lowest cost is determined as the second intra-frame prediction mode of the current block.
  • Example 2 the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are determined through the following steps S401-B21 and S401-B22.
  • TIMD enable flag indicates that the current block uses TIMD technology, and at least one reference reconstruction sample exists among the multiple reference reconstruction samples of the current block, determine the MPM of the current block:
  • S401-B22 Determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block according to the MPM.
  • the multiple reference reconstruction samples of the current block can be understood as the reconstructed area around the current block.
  • the MPM of the current block is determined according to the intra prediction modes of the multiple residual reconstruction samples around the current block.
  • Multiple reference reconstruction samples of the current block are preset, for example, determine the reconstruction area above the current block as a reconstruction sample of the current block, determine the left reconstruction area of the current block as a reconstruction sample of the current block, etc. .
  • the upper right region, upper region, upper left region, left region and lower left region of the current block are recorded as reference reconstruction samples of the current block.
  • Some of these reference reconstruction samples exist also known as valid, and some may not exist, that is, invalid, for example, the left area of the current block has been reconstructed, but the upper area of the current block has not been reconstructed, so it can be called the left side of the current block
  • the reference reconstructed samples of the area exist ie, valid
  • the reference reconstructed samples of the area above the current block do not exist (ie, invalid).
  • the intra prediction mode corresponding to the existing reference reconstruction sample Construct the MPM of the current block, for example, there are K reference reconstruction samples in the current block, and the intra prediction modes used in intra prediction are intra prediction mode 1, intra prediction mode 2..., intra prediction mode K, use intra prediction mode 1, intra prediction mode 2..., and intra prediction mode K to construct the MPM of the current block.
  • the above K is a positive integer less than 5.
  • the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are determined according to the MPM.
  • any intra-frame prediction mode in the MPM is determined as the first intra-frame prediction mode of the current block, and the number of intra-frame prediction modes in the MPM other than the first intra-frame prediction mode Any other intra-frame prediction mode is determined as the second intra-frame prediction mode of the current block.
  • the intra-frame prediction mode in the MPM is determined as the first intra-frame prediction mode, and one is determined from other intra-frame prediction modes, As the second intra prediction mode for the current block. For example, the intra-frame prediction mode with the lowest cost among other intra-frame prediction modes is determined as the second intra-frame prediction mode.
  • the intra prediction mode in the MPM is determined as the first intra prediction mode, and the Planar mode is determined as the second intra prediction mode.
  • the number of intra prediction modes in the MPM is equal to 1, it is determined not to perform weighted fusion prediction on the current block, and use the intra prediction mode in the MPM to predict the current block to obtain the target prediction of the current block value.
  • the cost corresponding to the intra-frame prediction mode determines the first intra-frame prediction mode and the second intra-frame prediction mode. For example, the candidate intra prediction mode with the lowest cost in the MPM is determined as the first intra prediction mode, and the candidate intra prediction mode with the second lowest cost in the MPM is determined as the second intra prediction mode.
  • the foregoing cost may be a cost such as SAD or SATD.
  • the above-mentioned process of determining the cost when predicting the template area of the current block using the candidate intra prediction mode in the MPM may be: The prediction value when the region is predicted; determine the cost corresponding to the candidate intra prediction mode according to the prediction value corresponding to the candidate intra prediction mode and the reconstruction value of the template region.
  • the prediction value when using the candidate intra prediction mode to predict the template area of the current block is obtained. Since the template area is a reconstructed area, the reconstruction value is known.
  • the cost corresponding to the candidate intra prediction mode is determined according to the prediction value corresponding to the intra prediction mode and the reconstruction value of the template region. For example, the SAD or SATD between the prediction value corresponding to the intra-frame prediction mode and the reconstruction value of the template area is determined as the cost of the candidate intra-frame prediction mode.
  • the video decoder does not determine the first intra prediction mode and the second intra prediction mode of the current block. Intra-frame prediction mode, but use Planar mode to predict the current block to obtain the target prediction value of the current block.
  • the first intra-frame prediction mode and the second intra-frame prediction mode of the current block may be determined.
  • the first intra prediction mode and the second intra prediction mode are determined according to the cost corresponding to the candidate intra prediction mode in the most probable mode list, including There are several ways:
  • Mode 1 determine the candidate intra prediction mode with the smallest cost in the most probable mode list as the first intra prediction mode, and determine the candidate intra prediction mode with the second lowest cost in the most probable mode list as the second Two intra prediction modes.
  • Mode 2 determining the candidate intra prediction mode with the smallest cost in the most probable mode list as the first initial mode, and determining the candidate intra prediction mode with the second lowest cost in the most probable mode list as the second initial mode; If at least one of the first initial mode and the second initial mode is an angle prediction mode, then according to the preset offset, the angle prediction mode in the first initial mode and the second initial mode is shifted to obtain A first intra prediction mode and a second intra prediction mode.
  • the first initial mode is an angle prediction mode
  • the first initial mode is used as the central prediction direction, and the left and right are respectively shifted by a certain angle to obtain mode1 + and mode1 -
  • the mode1 + and mode1 - are determined to be used mode1 - the cost when predicting the template area of the current block respectively, and the prediction mode with the smallest cost among mode1 + , mode1 - and the first initial mode is determined as the first intra-frame prediction mode.
  • the second initial mode is the angle prediction mode
  • the second initial mode is used as the center prediction direction, and the left and right are respectively shifted by a certain angle to obtain mode2 + and mode2 - , and it is determined to use mode2 + and mode2 - the cost when predicting the template area of the current block respectively, and the prediction mode with the smallest cost among mode2 + , mode2 - and the second initial mode is determined as the second intra-frame prediction mode.
  • the first initial mode is determined as the first intra-frame prediction mode
  • the second initial mode is determined as the second frame Intra-prediction mode
  • S402. Determine a weighted fusion condition of the current block according to the image content of the current sequence.
  • the foregoing weighted fusion condition is used to determine whether the current block is weighted and predicted through the first intra-frame prediction mode and the second intra-frame prediction mode.
  • S403. Determine a target prediction value of the current block according to the weighted fusion condition and at least one of the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the video decoder after the video decoder obtains the first intra-frame prediction mode and the second intra-frame prediction mode of the current block according to the above-mentioned step S401, it does not directly use the first intra-frame prediction mode and the second intra-frame prediction mode mode to perform weighted prediction on the current block, but it is necessary to judge whether the first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition of the current block.
  • first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition of the current block, use the first intra-frame prediction mode and the second intra-frame prediction mode to perform weighted prediction on the current block, for example, use the first frame
  • the intra prediction mode predicts the current block to obtain the first prediction value
  • uses the second intra prediction mode to predict the current block obtains the second prediction value
  • weights the first prediction value and the second prediction value to get the target prediction value of the current block.
  • the weight when the first predictive value and the second predictive value are weighted can be determined according to the cost of the first intra-frame prediction mode and the second intra-frame prediction mode, for example, the first intra-frame prediction mode performs The cost during prediction is recorded as the first cost cost1, and the cost when the second intra prediction mode predicts the current block is recorded as the second cost cost2.
  • the above-mentioned first cost and second cost may be SAD or SATD.
  • weight1 is the weight corresponding to the first predicted value
  • weight2 is the weight corresponding to the second predicted value.
  • weight1 cost2/(cost1+cost2)
  • weight2 1-weight1.
  • the first predicted value and the second predicted value are weighted according to the above formula (3) to obtain the target predicted value of the current block.
  • the first intra-frame prediction mode and the second intra-frame prediction mode do not meet the weighted fusion condition of the current block, use one of the first intra-frame prediction mode and the second intra-frame prediction mode to predict the current block, and obtain The target predictor for the current block.
  • the current block is predicted by using the prediction mode with the lowest cost among the first intra-frame prediction mode and the second intra-frame prediction mode to obtain a target prediction value of the current block.
  • the first intra prediction mode is the intra prediction mode with the lowest cost among the multiple prediction modes
  • the second intra prediction mode is the intra prediction mode with the second lowest cost among the multiple prediction modes.
  • the first intra prediction mode that is to say, the first cost is less than the second cost, therefore, when the first intra prediction mode and the second intra prediction mode do not meet the weighted fusion condition of the current block, the first intra prediction mode is used to The current block is predicted to obtain the target prediction value of the current block.
  • the current weighted fusion condition is fixed, that is to say, no matter what the image content is, the weighted fusion condition of the current block is fixed.
  • image content such as screen-recorded image content
  • weighted fusion prediction can be understood as a fuzzy prediction method, it will Reduced sharpening and color vibrancy in the image reduces prediction quality and introduces noise.
  • the present application determines the weighted fusion condition of the current block according to the image content. That is to say, this application provides differentiated weighted fusion conditions for image content, and the weighted fusion conditions corresponding to different image contents can be different, thereby ensuring weighted fusion prediction for image content that needs weighted fusion prediction to improve prediction. accuracy. For the image content that does not need weighted fusion prediction, no weighted fusion prediction is performed to avoid introducing unnecessary noise and ensure the prediction quality.
  • a sequence includes a series of images, and the series of images are generated in the same environment. Therefore, the image content of the images in a sequence is basically the same. Therefore, the present application determines the weighted fusion condition of the current block through the image content of the current sequence. It can be understood that the image content of the current block is of the same type as the image content of the current sequence, such as screen content, or other images collected by the camera. content etc.
  • the video decoding device can obtain the image content of the current sequence through an image recognition method. For example, when the video decoding device decodes the current sequence, it first uses an existing method to decode reconstructed images of the first few frames in the current sequence, for example, 2 frames. Perform image recognition on the reconstructed images of the previous frames to obtain the image content types of the reconstructed images of the previous frames, and use the image content types of the reconstructed images of the previous frames as the image content types of the current sequence.
  • the video decoding device performs image recognition on the reconstructed images of the previous frames, and the method for obtaining the image content of the reconstructed images of the previous frames may be a neural network model method.
  • the neural network model is pre-trained to identify the type of image content, and the video decoding device inputs the reconstructed images of the previous frames into the neural network model to obtain the image content of the reconstructed images of the previous frames output by the neural network model type.
  • the video decoding device may also use other methods to determine the type of image content of the reconstructed image of the previous frames, which is not limited in this application.
  • the video decoding device can obtain the image content of the current sequence through the indication information in the code stream. For example, the video encoding device writes the type of the image content of the current sequence into the code stream by means of a flag bit, and the video decoding device decodes the code stream to obtain the flag bit, and determine the type of the image content of the current sequence through the flag bit For example, when the value of the flag bit is 1, it indicates that the image content of the current sequence is the first image content; when the value of the flag bit is 0, it indicates that the image content of the current sequence is the second image content, wherein the first image The content is different from the second image content.
  • the weighted fusion condition of the current block is determined according to the image content of the current sequence, for example, when the image content of the current sequence is the first image content, the weighted fusion condition of the current block is determined to be The first fusion condition, if the image content of the current sequence is the second image content, then determine the weighted fusion condition of the current block as the second fusion condition, and if the image content of the current sequence is the third image content, then determine the weighted fusion condition of the current block The weighted fusion condition is the third fusion condition..., if the image content of the current sequence is the Nth image content, then determine the weighted fusion condition of the current block as the Nth fusion condition, specifically, as shown in Table 1 .
  • the above Table 1 shows that different image contents correspond to different weighted fusion conditions, and the above Table 1 is set in advance. In this way, after determining the image content of the current sequence, the video decoding device searches in Table 1, and determines the weighted fusion condition corresponding to the image content of the current sequence as the weighted fusion condition of the current block.
  • determining the weighted fusion condition of the current block according to the image content of the current sequence in the above S402 includes the following steps:
  • S402-A Decode the code stream to obtain a first flag, the first flag is used for whether to use the first technology, and the first technology is used under the first image content;
  • the first image content of the present application may be image content with sharp and vivid color features, such as screen recording content and the like.
  • the weighted fusion condition may only change when the image content of the current sequence is the first image content, and the weighted fusion condition may change if the image content of the current sequence is not the first image content. No change occurs. That is to say, if the image content of the current sequence is the first image content, the weighted fusion condition adopted is the first fusion condition; if the image content of the current sequence is not the first image content, the weighted fusion condition adopted is the second Fusion conditions. Wherein the first fusion condition is different from the second fusion condition.
  • the video encoder determines that the image content corresponding to the current block is the first image content, it determines that the current block can use the first technology, the first technology It can be understood that the technique provided by the embodiment of the present application is to determine the weighted fusion condition of the current block according to magnitude values of the first intra-frame prediction mode and the second intra-frame prediction mode. If the video encoder determines that the current block can use the first technology, it sets the first flag to true and encodes it into the code stream, for example, the value of the first flag is 1.
  • the video encoder determines that the image content corresponding to the current block is not the first image content, it determines that the current block cannot use the first technology, then sets the value of the first flag to false and encodes it into the code stream, for example, the first flag The value of is 0. In this way, the video decoder decodes the code stream to obtain the first flag, and then determines the weighted fusion condition of the current block according to the first flag.
  • the above-mentioned first flag may be a sequence-level flag, which is used to indicate whether the current sequence can use the first technology.
  • the above-mentioned first flag may be an image-level flag, used to indicate whether the current image can use the first technology.
  • a new field is added in the code stream to indicate the first flag.
  • the first flag is represented by the field sps_timd_blendoff_flag, which is a completely new field.
  • the above-mentioned first flag multiplexes the third flag in the current sequence, that is, the existing fields in the current sequence can be reused without adding new fields, thereby saving codewords.
  • the third field above is an intra-block copy (Intra-block copy, IBC for short) enable flag or a template matching prediction (Template matching prediction, TMP for short) enable flag, and the like.
  • the weighted fusion condition of the current block may be determined from multiple preset weighted fusion conditions according to the first flag. For example, Table 2 shows the weighted fusion conditions corresponding to the first flag.
  • the above table 2 shows the weighted fusion conditions corresponding to different values of the first flag.
  • the value of the first flag is 1, indicating that the image content of the current sequence is the first image content, and the corresponding weighted fusion condition is the first Fusion conditions.
  • the value of the first flag is 0, indicating that the image content of the current sequence is not the first image content, and the corresponding weighted fusion condition is the second fusion condition.
  • the video decoding device decodes the code stream to obtain the first flag, and according to the value of the first flag, query the weighted fusion condition of the current block from the above Table 2, for example, when the value of the first flag is When it is 1, it is determined that the weighted fusion condition of the current block is the first fusion condition, and when the value of the first flag is 0, it is determined that the weighted fusion condition of the current block is the second fusion condition.
  • query is performed in the above Table 2 to obtain the weighted fusion condition of the current block.
  • the weighted fusion condition of the current block is determined according to the first flag.
  • the above S402-B includes the following steps:
  • the video decoder decodes the code stream to obtain a first flag. If the first flag indicates that the current video decoder uses the first technology, for example, when the value of the first flag is 1, it indicates that the current video decoder can When using the first technology, the video decoder determines that the weighted fusion condition of the current block needs to be modified, and the existing weighted fusion condition cannot be used. At this time, the video decoder determines the weighted fusion condition for the current block again. Specifically, the video decoder determines the first fusion condition of the current block, and determines the first fusion condition as the weighted fusion condition of the current block.
  • the methods for determining the first fusion condition of the current block in the above S402-B1 include but are not limited to the following:
  • the first way modify the value of the first threshold coefficient to the first preset value, according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode, and the modified The first threshold coefficient determines the first fusion condition.
  • the above-mentioned first threshold coefficient is used to determine the first fusion condition.
  • the above-mentioned first threshold coefficient has a default value, such as 2 or other values.
  • the image content of the current sequence is the first image content (such as screen recording content)
  • the The first threshold coefficient is modified, for example, from a default value to a first preset value, and then according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode, and the modified second cost A threshold coefficient, used to determine the first fusion condition.
  • the above-mentioned first preset value is smaller than a default value of the first threshold coefficient.
  • the above-mentioned first preset value is a positive number less than 2, such as 1.9 or 1.95.
  • the method of determining the first fusion condition according to the first cost corresponding to the first intra prediction mode, the second cost corresponding to the second intra prediction mode, and the modified first threshold coefficient there is no limitation on the method of determining the first fusion condition according to the first cost corresponding to the first intra prediction mode, the second cost corresponding to the second intra prediction mode, and the modified first threshold coefficient .
  • the ratio of the second cost to the first cost is smaller than the modified first threshold coefficient as the first fusion condition of the current block.
  • the first fusion condition of the current block is: cost2/cost1 ⁇ a1, where cost1 is the first cost corresponding to the first intra prediction mode, cost2 is the second cost corresponding to the second intra prediction mode, and a1 is the modified The first threshold coefficient of .
  • the value of the first threshold coefficient before modification is a
  • the value after modification is a1
  • a is greater than a1.
  • the existing weighted fusion condition is: cost2/cost1 ⁇ a
  • the weighted fusion condition after modification of this application is: cost2/cost1 ⁇ a1
  • cost2 meets the weighted fusion conditions before modification
  • the value range of cost2 is: cost1 ⁇ cost2 ⁇ acost1
  • cost2 meets the weighted fusion conditions before modification
  • the value range of cost2 is: cost1 ⁇ cost2 ⁇ a1cost1.
  • the second cost is smaller than the product of the first cost and the modified first threshold coefficient as the first fusion condition of the current block.
  • the first fusion condition of the current block is: cost2 ⁇ a1 cost1.
  • the value of the first threshold coefficient before modification is a, and the value after modification is a1, and a is greater than a1.
  • the existing weighted fusion condition is: cost2 ⁇ a cost1
  • the weighted fusion condition after modification of this application is: cost2 ⁇ a1 cost1 since a1 is less than a, and cost1 is less than cost2, therefore, the modified weighted fusion condition of this application More strict, for example, when cost2 satisfies the weighted fusion condition before modification, the value range of cost2 is: cost1 ⁇ cost2 ⁇ acost1, and when cost2 meets the weighted fusion condition before modification, the value range of cost2 is: cost1 ⁇ cost2 ⁇ a1cost1 .
  • determining the target prediction value of the current block includes the following steps S403-A1:
  • cost2 ⁇ a1 cost1 it means that the first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition of the current block, therefore, using the first intra-frame prediction mode and the second intra-frame prediction mode to Weighted prediction is performed on the current block to obtain the target prediction value of the current block.
  • using the first intra-frame prediction mode to predict the current block to obtain the first prediction value use the second intra-frame prediction mode to predict the current block to obtain the second prediction value, and compare the first prediction value and the second prediction value
  • the two predicted values are weighted to obtain the target predicted value of the current block.
  • the weighted operation is used to obtain the target predicted value of the current block.
  • the weights of the weighted calculation of the first predicted value and the second predicted value can also be derived in the form of a weight matrix, for example, geometric Geometric partitioning mode (GPM) has 64 kinds of weight partitioning modes, Angular Weighted prediction mode (Angular Weighted prediction, AWP) has 56 kinds of weight partitioning modes.
  • the weight distribution corresponding to one weight division mode is selected from the 56 weight division modes as the weight of the first prediction value corresponding to the first intra prediction mode and the second prediction value corresponding to the second intra prediction mode. For example, if the first intra prediction mode is an angle prediction mode, then the weight distribution corresponding to the weight division mode that coincides or nearly coincides with the angle of the first intra prediction mode is determined as the first prediction value and the second prediction value corresponding weight.
  • the above S403 also includes the following S403-A2:
  • the video decoder when the first intra-frame prediction mode and the second intra-frame prediction mode do not meet the weighted fusion condition of the current block determined above, that is, cost2 ⁇ a1 cost1 is not satisfied, that is, the second intra-frame prediction mode
  • the video decoder does not perform weighted prediction on the current block, but uses the first intra prediction
  • the intra-frame prediction mode with the lowest cost among the second intra-frame prediction mode and the second intra-frame prediction mode is used for prediction. It can be seen from the above that the first cost is smaller than the second cost, so the video decoder directly uses the first intra prediction mode to predict the current block, and determines the predicted prediction value as the target prediction value of the current block.
  • the video decoder decodes the code stream to obtain the first flag, and if the first flag indicates that the first technology is used, the video decoder modifies the value of the first threshold coefficient to the first preset value , and according to the first cost corresponding to the first intra prediction mode, the second cost corresponding to the second intra prediction mode, and the modified first threshold coefficient, determine the first fusion condition, for example, make the second cost less than the The product of the first cost and the modified first threshold coefficient is used as a first fusion condition, and then the first fusion condition of the current block is used as a weighted fusion condition of the current block.
  • the weighted fusion condition of the current block is made more stringent, thereby reducing the weighted fusion condition of the first intra-frame prediction mode and the second intra-frame prediction mode to meet the modified weighted fusion of this application.
  • the conditional probability can reduce the probability of performing weighted prediction on the current block of the first image content, thereby ensuring the prediction quality of the current block of the first image content.
  • the video decoder may also determine the first fusion condition of the current block through the following second manner.
  • the second manner determine the first fusion condition of the current block according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode.
  • the first fusion condition of the current block is determined directly according to the first cost and the second cost, which simplifies the process of determining the first fusion condition of the current block, and improves the judgment based on the first fusion condition. Whether to weight the prediction rate of the current block, thereby improving the decoding efficiency.
  • the present application does not limit the manner of determining the first fusion condition of the current block according to the first cost and the second cost.
  • the first cost corresponding to the first intra-frame prediction mode and the second cost corresponding to the second intra-frame prediction mode are both greater than a certain preset value as the first fusion condition of the current block.
  • the first fusion condition is: cost1&cost2>b. That is, in the embodiment of the present application, when both the first cost and the second cost are greater than a certain preset value, it means that the prediction effects of the first intra-frame prediction mode and the second intra-frame prediction mode are not good.
  • weighted prediction can be performed through the first intra prediction mode and the second intra prediction mode, that is, the predicted values obtained by the first intra prediction mode and the second intra prediction mode are respectively predicted. , as the target prediction value of the current block to improve the prediction effect of the current block.
  • At least one of the first cost and the second cost is greater than or equal to a first preset threshold as the first fusion condition of the current block.
  • the first fusion condition of the current block is: at least one of the first cost and the second cost is greater than or equal to a first preset threshold.
  • the present application does not limit the specific value of the first preset threshold, which is specifically determined according to actual needs. In this example, if the first cost corresponding to the first intra prediction mode and/or the second cost corresponding to the second intra prediction mode are greater than or equal to the first preset value, it means that the first intra prediction mode and/or The prediction efficiency of the second intra prediction mode is not good.
  • weighted prediction can be performed through the first intra prediction mode and the second intra prediction mode, that is, the first intra prediction mode
  • the prediction value obtained by predicting separately with the second intra prediction mode is weighted, and used as the target prediction value of the current block, so as to improve the prediction effect of the current block.
  • determining the target prediction value of the current block includes the following steps S403-B1:
  • the first intra-frame prediction mode and the second intra-frame prediction mode are used, Determine the target predictor for the current block.
  • the first intra-frame prediction mode to predict the current block to obtain the first prediction value
  • use the second intra-frame prediction mode to predict the current block to obtain the second prediction value
  • the two predicted values are weighted to obtain the target predicted value of the current block.
  • the weighted operation is used to obtain the target predicted value of the current block.
  • the weights of the first predicted value and the second predicted value are derived by means of a weight matrix, and then weighted according to formula (3) to obtain the target predicted value of the current block.
  • the video decoder selects the weight distribution corresponding to one of the 64 weight division modes of GPM or the 56 weight division modes of AWP as the first prediction value corresponding to the first intra prediction mode and The weight of the second predictor corresponding to the second intra prediction mode. For example, if the first intra prediction mode is an angle prediction mode, then the weight distribution corresponding to the weight division mode that coincides or nearly coincides with the angle of the first intra prediction mode is determined as the first prediction value and the second prediction value corresponding weight.
  • the above S403 also includes the following S403-B2:
  • the first intra prediction mode and the second intra prediction mode do not meet the weighted fusion condition of the current block determined above, that is, the first cost corresponding to the first intra prediction mode and the second intra prediction
  • the second costs corresponding to the modes are both smaller than the first preset value, it indicates that the prediction effects of the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are better.
  • better prediction effect can be achieved when using an intra prediction mode to predict the current block.
  • the weighted prediction method that is, when the first intra prediction mode and the second intra prediction mode are used to perform weighted prediction on the current block, the prediction effect of the current block will be reduced, for example, the sharpness and color vividness of the current block will be reduced.
  • the video decoder uses the first intra prediction mode and the second intra prediction mode An intra prediction mode with the least cost is used for prediction. It can be seen from the above that the first cost is smaller than the second cost, so the video decoder directly uses the first intra prediction mode to predict the current block, and determines the predicted prediction value as the target prediction value of the current block.
  • the video decoder decodes the code stream to obtain the first flag. If the first flag indicates that the first technology is used, the video decoder uses the first cost and the second cost corresponding to the first intra prediction mode The second cost corresponding to the intra prediction mode determines the first fusion condition, for example, at least one of the first cost and the second cost is greater than or equal to the first preset threshold as the first fusion condition, and then the first fusion condition of the current block as the weighted fusion condition for the current block.
  • the video decoder uses the first intra-frame prediction mode and the second intra-frame prediction mode to determine the target prediction value of the current block. If both the first cost and the second cost are less than the first preset threshold, it indicates that the prediction effect of the first intra-frame prediction mode and the second intra-frame prediction mode of the current block is better. At this time, in order to ensure the prediction effect of the current block and To reduce the prediction complexity, the first intra prediction mode is used to determine the target prediction value of the current block.
  • the above second method may also be used as the weighted fusion condition of other image blocks. That is to say, the second manner above may be used as a first new weighted fusion condition to determine whether weighted fusion prediction is required for an image block.
  • the video decoder may also determine the first fusion condition of the current block in the following third manner.
  • a third manner determining a first fusion condition according to the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the first fusion condition of the current block is determined directly according to the first intra-frame prediction mode and the second intra-frame prediction mode, which simplifies the process of determining the first fusion condition of the current block and improves the The first fusion condition determines whether to perform weighted prediction on the current block, thereby improving decoding efficiency.
  • the present application does not limit the manner of determining the first fusion condition of the current block according to the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the difference between the index numbers of the first intra-frame prediction mode and the second intra-frame prediction mode is greater than a certain preset value as the first fusion condition of the current block.
  • the first fusion condition is: mode1_idx&mode2_idx>c, where mode1_idx is the index number of the first intra-frame prediction mode, and mode2_idx is the index number of the second intra-frame prediction mode.
  • the intra prediction mode such as the angle prediction mode shown in Figure 5 or Figure 6, the prediction effects corresponding to adjacent angle prediction modes are similar, for example, the angle prediction mode with index number 17 and the angle prediction mode with index number 18 The modes are all close to the horizontal direction, and their prediction effects are similar.
  • the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode is greater than a certain preset value, it means that the first intra-frame prediction mode and the second intra-frame prediction mode are two The larger the prediction mode, the corresponding prediction effect is also quite different.
  • weighted prediction can be performed through the first intra prediction mode and the second intra prediction mode, that is, the prediction obtained by predicting the first intra prediction mode and the second intra prediction mode respectively Values are weighted as the target prediction value of the current block to improve the prediction effect of the current block.
  • the difference between the index numbers of the first intra-frame prediction mode and the second intra-frame prediction mode is greater than or equal to a second preset threshold as the first fusion condition of the current block.
  • the first fusion condition of the current block is: mode1_idx&mode2_idx ⁇ d, where d is the second preset threshold.
  • the present application does not limit the specific value of the second preset threshold, which is specifically determined according to actual needs, for example, the second preset threshold is 3 or 4.
  • weighted prediction can be performed through the first intra prediction mode and the second intra prediction mode, that is, the prediction obtained by predicting the first intra prediction mode and the second intra prediction mode respectively Values are weighted as the target prediction value of the current block to improve the prediction effect of the current block.
  • determining the target prediction value of the current block includes the following steps S403-C1:
  • the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode when the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode is greater than or equal to the second preset threshold, it indicates that the difference between the first intra-frame prediction mode and the second intra-frame prediction mode The difference is large, and the corresponding prediction effect is also large. At this time, if one of the prediction modes with the smallest cost is used for independent prediction, it may cause inaccurate prediction.
  • the video decoder determines that the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode is greater than or equal to the second preset threshold value, then use the first intra-frame prediction mode and a second intra-frame prediction mode to determine the target prediction value of the current block.
  • the first intra-frame prediction mode to predict the current block to obtain the first prediction value
  • use the second intra-frame prediction mode to predict the current block to obtain the second prediction value
  • the two predicted values are weighted to obtain the target predicted value of the current block.
  • the weighted operation is used to obtain the target predicted value of the current block.
  • the weights of the first predicted value and the second predicted value are derived by means of a weight matrix, and then weighted according to formula (3) to obtain the target predicted value of the current block.
  • the video decoder selects the weight distribution corresponding to one of the 64 weight division modes of GPM or the 56 weight division modes of AWP as the first prediction value corresponding to the first intra prediction mode and The weight of the second predictor corresponding to the second intra prediction mode. For example, if the first intra prediction mode is an angle prediction mode, then the weight distribution corresponding to the weight division mode that coincides or nearly coincides with the angle of the first intra prediction mode is determined as the first prediction value and the second prediction value corresponding weight.
  • the above S403 also includes the following S403-C2:
  • the first intra-frame prediction mode and the second intra-frame prediction mode do not satisfy the weighted fusion condition of the current block determined above, that is, the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode
  • the value is smaller than the second preset threshold, it indicates that the prediction effects of the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are similar. At this time, better prediction effect can be achieved when using an intra prediction mode to predict the current block.
  • the video decoder uses the first intra prediction mode to predict the current block, and determines the predicted prediction value as the target prediction value of the current block.
  • the video decoder decodes the code stream to obtain the first flag, and if the first flag indicates that the first technology is used, the video decoder determines according to the first intra prediction mode and the second intra prediction mode
  • the first fusion condition for example, the difference between the index numbers of the first intra-frame prediction mode and the second intra-frame prediction mode is greater than or equal to the second preset threshold as the first fusion condition, and then the first fusion condition of the current block is used as the current Weighted fusion condition for blocks.
  • the first intra-frame prediction mode and the second intra-frame prediction mode are weighted as the target prediction value of the current block, so as to improve the prediction effect of the current block .
  • the first intra prediction mode is used to determine the target prediction value of the current block.
  • the above third manner may also be used as the weighted fusion condition of other image blocks. That is to say, the third manner above can be used as a first new weighted fusion condition to determine whether weighted fusion prediction is required for an image block.
  • the video decoder determines the first fusion condition of the current block through any of the above three methods, and uses the first fusion condition as The weighted fusion condition of the current block is used to judge whether to perform weighted prediction on the current block. While ensuring the prediction effect of the current block, the probability of weighted prediction on the current block is reduced, and the prediction quality of the current block is further improved.
  • the above step S402 before performing the above S402, it is first necessary to determine the types of the first intra-frame prediction mode and the second intra-frame preset mode, if at least one of the first intra-frame prediction mode and the second intra-frame prediction mode When the angle prediction mode is used, the above step S402 is executed, that is, the weighted fusion condition of the current block is determined according to the image content of the current sequence.
  • step S402 is not performed at this time, but the current The target predictor for the block.
  • the type of the current frame where the current block is located restricts whether to use the method of the embodiment of the present application, that is, according to the type of the current frame, determine whether to execute the image content according to the current sequence in S402, determine Step of the weighted fusion condition for the current block.
  • some types of frames can use the method of the embodiment of the present application, and some types of frames cannot use the method of the embodiment of the present application, so as to realize differentiated execution.
  • the type of the current frame is the type of the target frame, then according to the image content of the current sequence, determine the weighted fusion condition of the current block, for example, the technical solution of the present application is allowed for the I frame but not allowed for the B frame.
  • the target frame type includes at least one of an I frame, a P frame, and a B frame.
  • whether to use the method of the embodiment of the present application is restricted by frame type and image block size.
  • the video decoder is executing the method of the embodiment of the present application. First, determine the type of the current frame where the current block is located, and the size of the current block; according to the type of the current frame and the size of the current block, determine whether to The content is to determine the weighted fusion condition of the current block.
  • the size of the current block may include the height and width of the current block. Therefore, the video decoder determines whether to execute the above step S402 according to the height and width of the current block.
  • the type of the current frame is the first frame type and the size of the current block is greater than a first threshold, then determine the weight of the current block according to the image content of the current sequence Fusion conditions.
  • the type of the current frame is the second frame type and the size of the current block is greater than a second threshold, then determine the current block according to the image content of the current sequence The weighted fusion condition of .
  • the current first frame type is different from the second frame type.
  • the first threshold and the second threshold are also different. The present application does not limit the specific types of the first frame type and the second frame type, nor does it limit the specific values of the first threshold and the second threshold.
  • the second threshold is different from the first threshold, that is, the I frame and the B frame (or The applicable block size specified by P frame) may be different.
  • quantization parameters may also be used to limit whether to use the method of the embodiment of the present application.
  • the video decoder is executing the method of the embodiment of the present application. First, it determines the decoded code stream to obtain the quantization parameter corresponding to the current block. For example, the video decoder obtains the current block according to the frame-level permission flag or the sequence-level QP The quantization parameter, and then according to the quantization parameter, determine whether to determine the weighted fusion condition of the current block according to the image content of the current sequence.
  • the weighted fusion condition of the current block is determined according to the image content of the current sequence.
  • the present application does not limit the specific value of the third threshold, which is specifically determined according to actual needs.
  • the video decoder After the video decoder obtains the predicted value of the current block according to the above method, it decodes the code stream to obtain the residual value of the current block, and adds the predicted block to the residual block to obtain the reconstructed block of the current block.
  • the video decoder determines the first intra prediction mode and the second intra prediction mode of the current block by decoding the code stream; determines the weighted fusion condition of the current block according to the image content of the current sequence , the weighted fusion condition is used to determine whether the current block is weighted and predicted by the first intra prediction mode and the second intra prediction mode; according to the weighted fusion condition, and at least one of the first intra prediction mode and the second intra prediction mode One, to determine the target predictor for the current block.
  • the present application determines the weighted fusion condition of the current block according to the image content of the current sequence, and judges whether to perform weighted fusion prediction on the current block based on the weighted fusion condition, which can avoid the time when weighted fusion prediction is performed on image content that does not require weighted fusion prediction. , reduce the quality of prediction, introduce unnecessary noise problems, and then improve the accuracy of intra prediction.
  • the present application proposes a new method for determining weighted fusion conditions, specifically: determining the value of the first threshold coefficient as the second preset value, and the first threshold coefficient is used to determine the weighted fusion condition ; Determine the weighted fusion condition of the current block according to the first cost corresponding to the first intra prediction mode, the second cost corresponding to the second intra prediction mode, and the first threshold coefficient.
  • the above-mentioned first preset value is a positive number less than 2, such as 1.9 or 1.95.
  • the weighted fusion condition is that the second cost is less than the product of the first cost and the first threshold coefficient.
  • the existing weighted fusion condition is: cost2 ⁇ a cost1
  • the weighted fusion condition of this application is: cost2 ⁇ a2 cost1 where a2 is less than a, therefore, the weighted fusion condition of this application is more stringent, for example
  • cost2 satisfies the existing weighted fusion condition
  • the value range of cost2 is: cost1 ⁇ cost2 ⁇ acost1
  • cost2 meets the weighted fusion condition of this application
  • the value range of cost2 is: cost1 ⁇ cost2 ⁇ a2cost1.
  • the video decoder determines the weighted fusion condition of the current block according to the above method, it judges whether the first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition. Exemplarily, if the second cost is less than the product of the first cost and the first threshold coefficient, the target prediction value of the current block is determined using the first intra-frame prediction mode and the second intra-frame prediction mode. Exemplarily, if the second cost is greater than or equal to the product of the first cost and the first threshold coefficient, the first intra prediction mode is used to determine the target prediction value of the current block.
  • FIG. 9 is a schematic flowchart of an intra prediction method provided in an embodiment of the present application, as shown in FIG. 9 , including:
  • the TIMD permission flag is used to indicate whether the current decoder is allowed to use the TIMD technology.
  • TIMD enable flag indicates that the current decoder is allowed to use the TIMD technology, decode the code stream to obtain the TIMD enable flag.
  • the TIMD enable flag is used to indicate whether the current block uses TIMD technology.
  • TIMD enable flag indicates that the current block uses the TIMD technology, decode the code stream to obtain the first flag.
  • the first flag is used to indicate whether to use the first technology, and the first technology is used under the first image content.
  • TIMD enable flag indicates that the current block uses TIMD technology, and at least one reference reconstruction sample among the multiple reference reconstruction samples of the current block exists, determine the MPM of the current block, and determine the first frame of the current block according to the MPM intra prediction mode and a second intra prediction mode.
  • the first fusion condition of the current block is determined according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode.
  • the first fusion condition is determined according to the first intra-frame prediction mode and the second intra-frame prediction mode.
  • S506. Determine a target prediction value of the current block according to the first fusion condition and at least one of the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the video decoder After the video decoder obtains the target prediction value of the current block according to the above method, it decodes the code stream to obtain the residual value of the current block, and adds the prediction block to the residual block to obtain the reconstructed block of the current block.
  • the weighted fusion condition of the current block is determined, and based on the weighted fusion condition, it is judged whether to perform weighted fusion prediction on the current block. It avoids the problem of reducing the prediction quality and introducing unnecessary noise when weighted fusion prediction is performed on image content that does not require weighted fusion prediction, thereby improving the accuracy of intra-frame prediction.
  • FIG. 10 is a schematic flowchart of an intra prediction method provided by an embodiment of the present application. As shown in Figure 10, the method of the embodiment of the present application includes:
  • the video encoder receives a video stream, which is composed of a series of image frames, performs video encoding for each frame of image in the video stream, and divides the image frames into blocks to obtain the current block.
  • the current block is also referred to as a current coding block, a current image block, a coding block, a current coding unit, a current block to be coded, a current image block to be coded, and the like.
  • the block divided by the traditional method includes not only the chrominance component of the current block position, but also the luminance component of the current block position.
  • the separation tree technology can divide separate component blocks, such as a separate luma block and a separate chrominance block, where the luma block can be understood as only containing the luma component of the current block position, and the chrominance block can be understood as containing only the current block The chroma component of the position. In this way, the luma component and the chrominance component at the same position can belong to different blocks, and the division can have greater flexibility. If the separation tree is used in CU partitioning, some CUs contain both luma and chroma components, some CUs only contain luma components, and some CUs only contain chroma components.
  • the current block in the embodiment of the present application only includes chroma components, which may be understood as a chroma block.
  • the current block in this embodiment of the present application only includes a luma component, which may be understood as a luma block.
  • the current block includes both luma and chroma components.
  • the video encoder determines the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition
  • use the first intra-frame prediction mode to predict the current block, obtain the first prediction value of the current block, and use the second frame
  • the intra prediction mode predicts the current block to obtain the second prediction value of the current block, and performs weighted fusion of the first prediction value and the second prediction value to obtain the first prediction value of the current block.
  • one of the first intra-frame prediction mode and the second intra-frame prediction mode is used. , to predict the current block to obtain the first prediction value of the current block.
  • the video encoder when the video encoder determines that the current block allows fusion weighted prediction using two intra-frame prediction modes, the video encoder carries a second flag in the code stream, and the second flag is used to indicate whether the current block passes the first At least one of an intra prediction mode and a second intra prediction mode determines a first prediction value. If the video encoder uses at least one of the first intra-frame prediction mode and the second intra-frame prediction mode to determine the first prediction value, then set the second flag to true, for example, set the value of the second flag to 1, and Write the second flag which is true into the code stream, for example, into the code stream header. In this way, after the video decoder obtains the code stream, it decodes the code stream to obtain the second flag.
  • the video decoder determines that the current block passes through the first frame. At least one of the intra prediction mode and the second intra prediction mode determines the first prediction value.
  • the video encoder determines the first intra-frame prediction mode and the second intra-frame prediction mode in the same manner as the video decoder determines the first intra-frame prediction mode and the second intra-frame prediction mode. Reference may be made to the description of S401 above.
  • the video encoder does not determine the first predictive value of the current block through at least one of the first intra-frame prediction mode and the second intra-frame prediction mode, set the second flag to false, for example, set the value of the second flag to Set to 0, and write the second flag set to false into the code stream, for example, into the code stream header.
  • the video decoder decodes the code stream to obtain the second flag. If the second flag is false, for example, the value of the second flag is 0, the video decoder is not sure about the first intra prediction mode and the second intra prediction mode of the current block. Instead, it traverses the preset intra prediction modes, determines the intra prediction mode with the least cost to predict the current block, and obtains the first prediction value of the current block.
  • the above-mentioned second flag may be a TIMD enable flag, for example, sps_timd_enable_flag. That is to say, the video encoder obtains the use-allowed flag bit of the TIMD, and the use-allowed flag bit of the TIMD is a sequence-level flag bit.
  • the allowed flag bit of the TIMD is used to indicate whether the current sequence is allowed to use the TIMD technology. If the video encoder determines that the current sequence is allowed to use the TIMD technology, that is, the allowed use flag of the TIMD is true, for example, 1.
  • the video encoder determines the first intra-frame prediction mode and the second intra-frame prediction mode of the current block, and executes the method of the embodiment of the present application.
  • the video encoder uses the TIMD technology to determine the first prediction value of the current block
  • the The TIMD enable flag is set to true, for example, set to 1
  • the code stream is written, for example, the code stream header is written.
  • the video encoder does not use TIMD technology to determine the first prediction value of the current block, then set the TIMD enable flag to false, for example, to 0, and write the code stream, for example, into the code stream header.
  • the video decoder can parse out the TIMD enable flag from the code stream, and determine whether to use TIMD technology to determine the first prediction value of the current block according to the TIMD enable flag, thereby ensuring the consistency between the decoding end and the encoding end, and ensuring the prediction reliability.
  • the ways of determining the first intra-frame prediction mode and the second intra-frame prediction mode of the current block in S601 above include but are not limited to the following:
  • Method 1 traverse the preset intra prediction list, select the intra prediction mode with the lowest cost as the first intra prediction mode, and select the next smallest intra prediction mode as the second intra prediction mode.
  • the aforementioned preset intra-frame prediction list may include any one of intra-frame coding modes such as Direct Current (DC) mode, planar (PLANAR) mode, and angle mode.
  • DC Direct Current
  • PLANAR planar
  • angle mode angle mode
  • the video encoder traverses different intra prediction modes in the preset intra prediction list to perform predictive encoding on the current block, and then calculates the cost corresponding to each prediction mode in the multiple prediction modes.
  • the intra-frame prediction mode corresponding to the minimum cost is determined as the first intra-frame prediction mode of the current block, and the intra-frame prediction mode corresponding to the next smallest cost is determined as the second intra-frame prediction mode of the current block.
  • the current block and the predicted value of the current block may be used to determine SAD and SATD.
  • a certain intra prediction mode is used to predict the current block to obtain a predicted value of the current block, and the pixel difference between the current block and the predicted value of the current block is determined as the SAD corresponding to the intra prediction mode.
  • the current block is subtracted from the predicted value of the current block to obtain the residual value of the current block, and the residual value is subjected to Hadamard transformation, and then the sum of the absolute values of each element is calculated, and then the SATD corresponding to the intra prediction mode is obtained.
  • Way 2 Determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block according to the MPM of the current block. That is, the above S601 includes the following steps of S601-A1 and S601-A2:
  • S601-A2 Determine a first intra-frame prediction mode and a second intra-frame prediction mode according to the MPM.
  • the MPM intra-mode coding technology can be used to improve codec efficiency.
  • Intra prediction modes that refer to surrounding coded blocks take advantage of spatial correlation.
  • the MPM is composed according to the intra prediction mode of the decoded area around the current block, so that the video encoder obtains the intra prediction mode used by the image blocks in the decoded area around the current block, and then forms the MPM of the current block .
  • the MPM of the current block is formed by using the intra-frame prediction modes of the upper, upper left, and upper right regions of the current block.
  • the intra prediction modes of the coded areas in the upper right area, upper area, upper left area, left area, and lower left area of the current block The MPM that makes up the current block.
  • the upper right area uses intra prediction mode 1 when encoding
  • the upper area uses intra prediction mode 2 when encoding
  • the upper left area uses intra prediction mode 3 when encoding
  • the left area uses frame when encoding
  • Intra prediction mode 2 the intra prediction mode 4 used in the encoding of the lower left area, so that it can be determined that the MPM of the current block includes intra prediction mode 1, intra prediction mode 2, intra prediction mode 3 and intra prediction mode 4.
  • the intra prediction mode corresponding to the coded area in these areas is used to construct the current block. MPM.
  • the current block is the first code block to be encoded, that is to say, there is no coded area around the current block, at this time, several intra prediction modes can be selected from the preset intra prediction modes mode builds the MPM for the current block.
  • the current block is the first block to be encoded
  • the first intra-frame prediction mode and the second intra-frame prediction mode are determined according to the MPM.
  • the intra prediction modes in the MPM are recorded as candidate intra prediction modes.
  • the manner of determining the first intra-frame prediction mode and the second intra-frame prediction mode includes but not limited to the following examples:
  • Example 1 Determine a candidate intra-frame prediction mode in the above MPM as the first intra-frame prediction mode, and determine a candidate intra-frame prediction mode in the MPM other than the first intra-frame prediction mode as the second intra-frame prediction mode predictive mode. For example, any candidate intra prediction mode in the MPM is determined as the first intra prediction mode, and any candidate preset mode in the MPM except the first intra prediction mode is determined as the second intra prediction mode.
  • Example 2 determine the cost when using the candidate intra prediction mode in the MPM to predict the current block; determine the first intra prediction mode and the second intra prediction mode according to the cost corresponding to the candidate intra prediction mode in the MPM model. For example, each candidate intra prediction mode in the MPM is used to predictively encode the current block, and the cost corresponding to each candidate intra prediction mode is obtained. Next, according to the cost corresponding to each candidate intra prediction mode in the MPM, determine the first intra prediction mode and the second intra prediction mode, for example, determine the candidate intra prediction mode with the smallest cost in the MPM as the first intra prediction mode The prediction mode is to determine the candidate intra-frame prediction mode with the second lowest cost in the MPM as the second intra-frame prediction mode.
  • the foregoing cost may be SAD or SATD, etc., which is not limited in this application.
  • the first intra prediction mode and the second intra prediction mode of the current block are determined by determining the MPM of the current block and the cost of predictive encoding of the current block according to each candidate intra prediction mode in the MPM, Since there are fewer intra-frame prediction modes included in the MPM, the complexity of determining the first intra-frame prediction mode and the second intra-frame prediction mode is reduced, and the accuracy of the first intra-frame prediction mode and the second intra-frame prediction mode is improved. Determine the speed to improve forecasting efficiency.
  • the following method 3 is adopted to determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block.
  • S601 includes the following steps of S601-B1 and S601-B2:
  • TIMD allowed flag indicates that the current sequence allows the TIMD technology, determine a first intra-frame prediction mode and a second intra-frame prediction mode of the current block.
  • the TIMD technology is based on templates to derive the intra prediction mode. Based on this, when the video encoder determines that the current block can use the TIMD technology according to the IMD permission flag, it can predict the template of the current block shown in Figure 7 Encoding, determining the first intra-frame prediction mode and the second intra-frame prediction mode of the current block, instead of directly performing predictive coding on the current block to determine the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the effect of the intra-frame prediction mode can be determined according to the difference between the predicted value of the template and the reconstructed value, and then the first intra-frame prediction mode of the current block can be determined accurately and quickly and a second intra prediction mode.
  • the ways of determining the first intra-frame prediction mode and the second intra-frame prediction mode of the current block in the above S601-B2 include but are not limited to the following examples:
  • Example 1 traversing the preset intra-frame prediction mode list, using each intra-frame prediction mode in the intra-frame prediction mode list to perform predictive encoding on the template of the current block, and obtaining the prediction value corresponding to each prediction mode.
  • compare the prediction value corresponding to each prediction mode with the reconstruction value of the template for example, calculate the cost between the prediction value corresponding to the prediction mode and the reconstruction value of the template, such as SAD or SATD, and determine the prediction mode with the smallest cost As the first intra-frame prediction mode of the current block, the prediction mode with the second lowest cost is determined as the second intra-frame prediction mode of the current block.
  • Example 2 the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are determined through the following steps S601-B21 and S601-B22.
  • TIMD permission flag indicates that the current sequence allows the use of TIMD technology, and at least one reference reconstruction sample exists among the multiple reference reconstruction samples of the current block, then determine the MPM of the current block:
  • S601-B22 Determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block according to the MPM.
  • the multiple reference reconstruction samples of the current block can be understood as the reconstructed area around the current block.
  • the MPM of the current block is determined according to the intra prediction modes of the multiple residual reconstruction samples around the current block.
  • Multiple reference reconstruction samples of the current block are preset, for example, determine the reconstruction area above the current block as a reconstruction sample of the current block, determine the left reconstruction area of the current block as a reconstruction sample of the current block, etc. .
  • the upper right area, upper area, upper left area, left area and lower left area of the current block are recorded as reference reconstruction samples of the current block.
  • Some of these reference reconstruction samples exist also known as valid, and some may not exist, that is, invalid, for example, the left area of the current block has been reconstructed, but the upper area of the current block has not been reconstructed, so it can be called the left side of the current block
  • the reference reconstructed samples of the area exist (ie, valid), and the reference reconstructed samples of the area above the current block do not exist (ie, invalid).
  • the intra prediction mode corresponding to the existing reference reconstruction sample to construct the MPM of the current block.
  • the intra prediction modes used in intra prediction are intra prediction mode 1, intra prediction mode 2..., intra For prediction mode K, use intra prediction mode 1, intra prediction mode 2..., and intra prediction mode K to construct the MPM of the current block.
  • the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are determined according to the MPM.
  • any intra-frame prediction mode in the MPM is determined as the first intra-frame prediction mode of the current block, and the number of intra-frame prediction modes in the MPM other than the first intra-frame prediction mode Any other intra-frame prediction mode is determined as the second intra-frame prediction mode of the current block.
  • the intra-frame prediction mode in the MPM is determined as the first intra-frame prediction mode, and one is determined from other intra-frame prediction modes, As the second intra prediction mode for the current block. For example, the intra-frame prediction mode with the lowest cost among other intra-frame prediction modes is determined as the second intra-frame prediction mode.
  • the intra prediction mode in the MPM is determined as the first intra prediction mode, and the Planar mode is determined as the second intra prediction mode.
  • the number of intra-frame prediction modes in the MPM is equal to 1, it is determined not to perform weighted fusion prediction on the current block, and use the intra-frame prediction modes in the MPM to predict the current block to obtain the first Predictive value.
  • the cost corresponding to the intra-frame prediction mode determines the first intra-frame prediction mode and the second intra-frame prediction mode. For example, the candidate intra prediction mode with the lowest cost in the MPM is determined as the first intra prediction mode, and the candidate intra prediction mode with the second lowest cost in the MPM is determined as the second intra prediction mode.
  • the above cost may be rate-distortion optimization (Rate-Distortion Optimization, RDO), and may also be an approximate cost such as SAD or SATD.
  • RDO rate-distortion optimization
  • the above-mentioned process of determining the cost when predicting the template area of the current block using the candidate intra prediction mode in the MPM may be: The prediction value when the region is predicted; determine the cost corresponding to the candidate intra prediction mode according to the prediction value corresponding to the candidate intra prediction mode and the reconstruction value of the template region.
  • the prediction value when using the candidate intra prediction mode to predict the template area of the current block is obtained. Since the template area is a reconstructed area, the reconstruction value is known.
  • the cost corresponding to the candidate intra prediction mode is determined according to the prediction value corresponding to the intra prediction mode and the reconstruction value of the template area. For example, the SAD or SATD between the prediction value corresponding to the intra-frame prediction mode and the reconstruction value of the template area is determined as the cost of the candidate intra-frame prediction mode.
  • the video encoder does not determine the first intra prediction mode and the second intra prediction mode of the current block. Instead, use the Planar mode to predict the current block to obtain the first prediction value of the current block.
  • the first intra-frame prediction mode and the second intra-frame prediction mode of the current block may be determined.
  • the first intra prediction mode and the second intra prediction mode are determined according to the cost corresponding to the candidate intra prediction mode in the most probable mode list, including There are several ways:
  • Mode 1 determine the candidate intra prediction mode with the smallest cost in the most probable mode list as the first intra prediction mode, and determine the candidate intra prediction mode with the second lowest cost in the most probable mode list as the second Two intra prediction modes.
  • Mode 2 determining the candidate intra prediction mode with the smallest cost in the most probable mode list as the first initial mode, and determining the candidate intra prediction mode with the second lowest cost in the most probable mode list as the second initial mode; If at least one of the first initial mode and the second initial mode is an angle prediction mode, then according to the preset offset, the angle prediction mode in the first initial mode and the second initial mode is shifted to obtain A first intra prediction mode and a second intra prediction mode.
  • the first initial mode is an angle prediction mode
  • the first initial mode is used as the central prediction direction, and the left and right are respectively shifted by a certain angle to obtain mode1 + and mode1 -
  • the mode1 + and mode1 - are determined to be used mode1 - the cost when predicting the template area of the current block respectively, and the prediction mode with the smallest cost among mode1 + , mode1 - and the first initial mode is determined as the first intra prediction mode.
  • the second initial mode is the angle prediction mode
  • the second initial mode is used as the center prediction direction, and the left and right are respectively shifted by a certain angle to obtain mode2 + and mode2 - , and it is determined to use mode2 + and mode2 - the cost when predicting the template area of the current block respectively, and the prediction mode with the smallest cost among mode2 + , mode2 - and the second initial mode is determined as the second intra-frame prediction mode.
  • the first initial mode is determined as the first intra-frame prediction mode
  • the second initial mode is determined as the second frame Intra-prediction mode
  • S602. Determine a weighted fusion condition of the current block according to the image content of the current sequence.
  • the foregoing weighted fusion condition is used to determine whether the current block is weighted and predicted through the first intra-frame prediction mode and the second intra-frame prediction mode.
  • S603. Determine a first prediction value of the current block according to the weighted fusion condition and at least one of the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the video encoder after the video encoder obtains the first intra-frame prediction mode and the second intra-frame prediction mode of the current block according to the above-mentioned step S601, it does not directly use the first intra-frame prediction mode and the second intra-frame prediction mode mode to perform weighted prediction on the current block, but it is necessary to judge whether the first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition of the current block.
  • first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition of the current block, use the first intra-frame prediction mode and the second intra-frame prediction mode to perform weighted prediction on the current block, for example, use the first frame
  • the intra prediction mode predicts the current block to obtain the first prediction value
  • uses the second intra prediction mode to predict the current block obtains the second prediction value
  • weights the first prediction value and the second prediction value to get the first prediction value of the current block.
  • the weight when the first predictive value and the second predictive value are weighted can be determined according to the cost of the first intra-frame prediction mode and the second intra-frame prediction mode, for example, the first intra-frame prediction mode performs The cost during prediction is recorded as the first cost cost1, and the cost when the second intra prediction mode predicts the current block is recorded as the second cost cost2.
  • the above-mentioned first cost and second cost may be SAD or SATD.
  • weight1 is the weight corresponding to the first predicted value
  • weight2 is the weight corresponding to the second predicted value.
  • weight1 cost2/(cost1+cost2)
  • weight2 1-weight1.
  • the first predicted value and the second predicted value are weighted according to the above formula (3) to obtain the first predicted value of the current block.
  • the first intra-frame prediction mode and the second intra-frame prediction mode do not meet the weighted fusion condition of the current block, use one of the first intra-frame prediction mode and the second intra-frame prediction mode to predict the current block, and obtain The first predictor of the current block.
  • the current block is predicted by using the prediction mode with the lowest cost among the first intra prediction mode and the second intra prediction mode to obtain the first prediction value of the current block.
  • the first intra prediction mode is the intra prediction mode with the lowest cost among the multiple prediction modes
  • the second intra prediction mode is the intra prediction mode with the second lowest cost among the multiple prediction modes.
  • the first intra prediction mode that is to say, the first cost is less than the second cost, therefore, when the first intra prediction mode and the second intra prediction mode do not meet the weighted fusion condition of the current block, the first intra prediction mode is used to The current block is predicted to obtain the first predicted value of the current block.
  • the current weighted fusion condition is fixed, that is to say, no matter what the image content is, the weighted fusion condition of the current block is fixed.
  • image content such as screen-recorded image content
  • weighted fusion prediction can be understood as a fuzzy prediction method, it will Reduced sharpening and color vibrancy in the image reduces prediction quality and introduces noise.
  • the present application determines the weighted fusion condition of the current block according to the image content. That is to say, this application provides differentiated weighted fusion conditions for image content, and the weighted fusion conditions corresponding to different image contents can be different, thereby ensuring weighted fusion prediction for image content that needs weighted fusion prediction to improve prediction. accuracy. For the image content that does not need weighted fusion prediction, no weighted fusion prediction is performed to avoid introducing unnecessary noise and ensure the prediction quality.
  • a sequence includes a series of images, and the series of images are generated in the same environment. Therefore, the image content of the images in a sequence is basically the same. Therefore, the present application determines the weighted fusion condition of the current block through the image content of the current sequence. It can be understood that the image content of the current block is of the same type as the image content of the current sequence, such as screen content, or other images collected by the camera. content etc.
  • the weighted fusion condition of the current block is determined according to the image content of the current sequence, for example, when the image content of the current sequence is the first image content, the weighted fusion condition of the current block is determined to be the first fusion condition, if When the image content of the current sequence is the second image content, then determine that the weighted fusion condition of the current block is the second fusion condition; if the image content of the current sequence is the third image content, then determine that the weighted fusion condition of the current block is the third Fusion condition..., if the image content of the current sequence is the Nth image content, then determine the weighted fusion condition of the current block as the Nth fusion condition, specifically, as shown in Table 1 above.
  • the above Table 1 shows that different image contents correspond to different weighted fusion conditions, and the above Table 1 is set in advance. In this way, after determining the image content of the current sequence, the video encoding device searches in Table 1, and determines the weighted fusion condition corresponding to the image content of the current sequence as the weighted fusion condition of the current block.
  • the weighted fusion condition may only change when the image content of the current sequence is the first image content, and the weighted fusion condition may change if the image content of the current sequence is not the first image content. No change occurs. That is to say, if the image content of the current sequence is the first image content, the weighted fusion condition adopted is the first fusion condition; if the image content of the current sequence is not the first image content, the weighted fusion condition adopted is the second Fusion conditions. Wherein the first fusion condition is different from the second fusion condition.
  • the video encoder encodes a first flag into the code stream, the first flag is used to indicate whether to use the first technology, the first The technique is used under the first image content. For example, when the image content of the current sequence is the first image content, the video encoder sets the first flag to 1 and encodes it into the code stream; if the image content of the current sequence is not the first image content, the video encoder sets the After the first flag is set to 0, it is encoded into the code stream. In this way, the video decoder decodes the code stream to obtain the first flag, and then determines the weighted fusion condition of the current block according to the first flag.
  • a new field is added in the code stream to indicate the first flag.
  • the first flag is represented by the field sps_timd_blendoff_flag, which is a completely new field.
  • the above-mentioned first flag multiplexes the third flag in the current sequence, that is, the existing fields in the current sequence can be reused without adding new fields, thereby saving codewords.
  • the third field above is an intra-block copy (Intra-block copy, IBC for short) enable flag or a template matching prediction (Template matching prediction, TMP for short) enable flag, and the like.
  • the above S602 includes the following steps:
  • the video encoder determines that the weighted fusion condition of the current block needs to be modified, and the existing weighted fusion condition cannot be used. At this time, the video The encoder re-determines the weighted fusion condition for the current block. Specifically, the video encoder determines the first fusion condition of the current block, and determines the first fusion condition as the weighted fusion condition of the current block.
  • the methods for determining the first fusion condition of the current block in S602-B1 above include but are not limited to the following:
  • the first way modify the value of the first threshold coefficient to the first preset value, according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode, and the modified The first threshold coefficient determines the first fusion condition.
  • the above-mentioned first threshold coefficient is used to determine the first fusion condition.
  • the above-mentioned first threshold coefficient has a default value, such as 2 or other values.
  • the image content of the current sequence is the first image content (such as screen recording content)
  • the The first threshold coefficient is modified, for example, from a default value to a first preset value, and then according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode, and the modified second cost A threshold coefficient, used to determine the first fusion condition.
  • the above-mentioned first preset value is smaller than a default value of the first threshold coefficient.
  • the above-mentioned first preset value is a positive number less than 2, such as 1.9 or 1.95.
  • the second cost is made smaller than the product of the first cost and the modified first threshold coefficient.
  • the first fusion condition of the current block is: cost2 ⁇ a1 cost1.
  • the value of the first threshold coefficient before modification is a, and the value after modification is a1, and a is greater than a1.
  • the existing weighted fusion condition is: cost2 ⁇ a cost1
  • the weighted fusion condition after modification of this application is: cost2 ⁇ a1 cost1 since a1 is less than a, and cost1 is less than cost2, therefore, the modified weighted fusion condition of this application More strict, for example, when cost2 satisfies the weighted fusion condition before modification, the value range of cost2 is: cost1 ⁇ cost2 ⁇ acost1, and when cost2 meets the weighted fusion condition before modification, the value range of cost2 is: cost1 ⁇ cost2 ⁇ a1cost1 .
  • determining the first prediction value of the current block includes the following steps S603-A1:
  • cost2 ⁇ a1 cost1 it means that the first intra-frame prediction mode and the second intra-frame prediction mode meet the weighted fusion condition of the current block, therefore, using the first intra-frame prediction mode and the second intra-frame prediction mode to Weighted prediction is performed on the current block to obtain the first prediction value of the current block.
  • use the first intra-frame prediction mode to predict the current block to obtain the first prediction value use the second intra-frame prediction mode to predict the current block to obtain the second prediction value, and compare the first prediction value and the second prediction value
  • the two prediction values are weighted to obtain the first prediction value of the current block.
  • the weighting operation is used to obtain the first prediction value of the current block.
  • the above S603 also includes the following S603-A2:
  • the video encoder when the first intra-frame prediction mode and the second intra-frame prediction mode do not meet the weighted fusion condition of the current block determined above, that is, cost2 ⁇ a1 cost1 is not satisfied, that is, the second intra-frame prediction mode
  • the video encoder does not perform weighted prediction on the current block, but uses the first intra prediction
  • the intra-frame prediction mode with the lowest cost among the second intra-frame prediction mode and the second intra-frame prediction mode is used for prediction. It can be seen from the above that the first cost is smaller than the second cost, so the video encoder directly uses the first intra prediction mode to predict the current block, and determines the predicted prediction value as the first prediction value of the current block.
  • the video encoder modifies the value of the first threshold coefficient to the first preset value, and according to the first intra-frame
  • the first cost corresponding to the prediction mode, the second cost corresponding to the second intra prediction mode, and the modified first threshold coefficient determine the first fusion condition, for example, the second cost is smaller than the first cost and the modified
  • the product of the first threshold coefficient is used as a first fusion condition, and then the first fusion condition of the current block is used as a weighted fusion condition of the current block.
  • the weighted fusion condition of the current block is made more stringent, thereby reducing the weighted fusion condition of the first intra-frame prediction mode and the second intra-frame prediction mode to meet the modified weighted fusion of this application.
  • the conditional probability can reduce the probability of performing weighted prediction on the current block of the first image content, thereby ensuring the prediction quality of the current block of the first image content.
  • the video encoder may also determine the first fusion condition of the current block through the following second manner.
  • the second manner determine the first fusion condition of the current block according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode.
  • the first fusion condition of the current block is determined directly according to the first cost and the second cost, which simplifies the process of determining the first fusion condition of the current block, and improves the judgment based on the first fusion condition. Whether to weight the prediction rate of the current block, thereby improving the coding efficiency.
  • the present application does not limit the manner of determining the first fusion condition of the current block according to the first cost and the second cost.
  • At least one of the first cost and the second cost is greater than or equal to a first preset threshold as the first fusion condition of the current block.
  • the first fusion condition of the current block is: at least one of the first cost and the second cost is greater than or equal to a first preset threshold.
  • the present application does not limit the specific value of the first preset threshold, which is specifically determined according to actual needs.
  • the first cost corresponding to the first intra prediction mode and/or the second cost corresponding to the second intra prediction mode are greater than or equal to the first preset value, it means that the first intra prediction mode and/or The prediction efficiency of the second intra-frame prediction mode is not good.
  • weighted prediction can be performed through the first intra-frame prediction mode and the second intra-frame prediction mode, that is, the first intra-frame prediction mode
  • the prediction value obtained by predicting separately with the second intra prediction mode is weighted, and used as the first prediction value of the current block, so as to improve the prediction effect of the current block.
  • determining the first prediction value of the current block includes the following steps S603-B1:
  • the prediction effect of the first intra-frame prediction mode and/or the second intra-frame prediction mode of the current block is not good
  • the prediction efficiency of the prediction mode with the smallest cost cannot be guaranteed, which may cause inaccurate prediction.
  • the video encoder determines that at least one of the first cost and the second cost is greater than or equal to the first preset threshold, the first intra-frame prediction mode and the second intra-frame prediction mode are used, A first predictor for the current block is determined.
  • the first intra-frame prediction mode to predict the current block to obtain the first prediction value
  • use the second intra-frame prediction mode to predict the current block to obtain the second prediction value
  • the two prediction values are weighted to obtain the first prediction value of the current block.
  • the weighting operation is used to obtain the first prediction value of the current block.
  • the above S603 also includes the following S603-B2:
  • the first intra prediction mode and the second intra prediction mode do not meet the weighted fusion condition of the current block determined above, that is, the first cost corresponding to the first intra prediction mode and the second intra prediction
  • the second costs corresponding to the modes are both smaller than the first preset value, it indicates that the prediction effects of the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are better.
  • better prediction effect can be achieved when using an intra prediction mode to predict the current block.
  • the weighted prediction method that is, when the first intra prediction mode and the second intra prediction mode are used to perform weighted prediction on the current block, the prediction effect of the current block will be reduced, for example, the sharpness and color vividness of the current block will be reduced.
  • the video encoder uses the first intra prediction mode and the second intra prediction mode An intra prediction mode with the least cost is used for prediction. It can be seen from the above that the first cost is smaller than the second cost, so the video encoder directly uses the first intra prediction mode to predict the current block, and determines the predicted prediction value as the first prediction value of the current block.
  • the video encoder uses the first cost corresponding to the first intra-frame prediction mode and the first cost corresponding to the second intra-frame prediction mode
  • the second cost determines the first fusion condition, for example, at least one of the first cost and the second cost is greater than or equal to the first preset threshold as the first fusion condition, and then the first fusion condition of the current block is used as the weighted fusion condition of the current block .
  • the video encoder uses the first intra-frame prediction mode and the second intra-frame prediction mode to determine the first prediction value of the current block. If both the first cost and the second cost are less than the first preset threshold, it indicates that the prediction effect of the first intra-frame prediction mode and the second intra-frame prediction mode of the current block is better. At this time, in order to ensure the prediction effect of the current block and To reduce the prediction complexity, the first intra prediction mode is used to determine the first prediction value of the current block.
  • the above second method may also be used as the weighted fusion condition of other image blocks. That is to say, the second manner above may be used as a first new weighted fusion condition to determine whether weighted fusion prediction is required for an image block.
  • the video encoder may also determine the first fusion condition of the current block in the following third manner.
  • a third manner determining a first fusion condition according to the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the first fusion condition of the current block is determined directly according to the first intra-frame prediction mode and the second intra-frame prediction mode, which simplifies the process of determining the first fusion condition of the current block and improves the The first fusion condition determines whether to perform weighted prediction on the current block, thereby improving coding efficiency.
  • the present application does not limit the manner of determining the first fusion condition of the current block according to the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the difference between the index numbers of the first intra-frame prediction mode and the second intra-frame prediction mode is greater than or equal to a second preset threshold as the first fusion condition of the current block.
  • the first fusion condition of the current block is: mode1_idx&mode2_idx ⁇ d, where d is the second preset threshold.
  • the present application does not limit the specific value of the second preset threshold, which is specifically determined according to actual needs, for example, the second preset threshold is 3 or 4.
  • weighted prediction can be performed through the first intra prediction mode and the second intra prediction mode, that is, the prediction obtained by predicting the first intra prediction mode and the second intra prediction mode respectively Values are weighted as the first prediction value of the current block to improve the prediction effect of the current block.
  • determining the first prediction value of the current block includes the following steps S603-C1:
  • the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode when the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode is greater than or equal to the second preset threshold, it indicates that the difference between the first intra-frame prediction mode and the second intra-frame prediction mode The difference is large, and the corresponding prediction effect is also large. At this time, if one of the prediction modes with the smallest cost is used for independent prediction, it may cause inaccurate prediction.
  • the first intra-frame prediction is used mode and a second intra-frame prediction mode to determine the first prediction value of the current block.
  • the first intra-frame prediction mode to predict the current block to obtain the first prediction value
  • use the second intra-frame prediction mode to predict the current block to obtain the second prediction value
  • the two predictive values are weighted to obtain the first predictive value of the current block.
  • the weighting operation is performed to obtain the first predictive value of the current block.
  • the above S603 also includes the following S603-C2:
  • the first intra-frame prediction mode and the second intra-frame prediction mode do not satisfy the weighted fusion condition of the current block determined above, that is, the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode
  • the value is smaller than the second preset threshold, it indicates that the prediction effects of the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are similar. At this time, better prediction effect can be achieved when using an intra prediction mode to predict the current block.
  • the video encoder uses the first intra prediction mode to predict the current block, and determines the predicted prediction value as the first prediction value of the current block.
  • the video encoder determines the first fusion condition according to the first intra-frame prediction mode and the second intra-frame prediction mode, for example, the The index number difference between the first intra prediction mode and the second intra prediction mode is greater than or equal to the second preset threshold as the first fusion condition, and then the first fusion condition of the current block is used as the weighted fusion condition of the current block.
  • the first intra-frame prediction mode and the second intra-frame prediction mode are greater than or equal to the second preset threshold, the first intra-frame prediction mode and the second intra-frame prediction mode The difference is large, and the corresponding prediction effect is also large.
  • the prediction values predicted by the first intra prediction mode and the second intra prediction mode are weighted as the first prediction value of the current block, so as to improve the prediction of the current block Effect. If the index number difference between the first intra-frame prediction mode and the second intra-frame prediction mode is less than the second preset threshold, it means that the prediction effects of the first intra-frame prediction mode and the second intra-frame prediction mode of the current block are similar, At this time, in order to ensure the prediction effect of the current block and reduce the prediction complexity, the first intra prediction mode is used to determine the first prediction value of the current block.
  • the above third manner may also be used as the weighted fusion condition of other image blocks. That is to say, the third manner above can be used as a first new weighted fusion condition to determine whether weighted fusion prediction is required for an image block.
  • the first prediction value of the current block may be determined according to the first intra-frame prediction mode and/or the second intra-frame prediction mode, and then, the following step S604 is performed.
  • the above-mentioned first predictive value of the current block may be directly determined as the target predictive value of the current block.
  • the above S604 includes the following steps:
  • the foregoing first encoding cost may be the RDO cost, and optionally, may also be an approximate cost such as SAD or SATD, which is not limited in this application.
  • S604-A2 Determine a second coding cost when each intra prediction mode in the candidate prediction set predicts the current block.
  • the above candidate prediction set includes at least one intra-frame prediction mode, traverse each intra-frame prediction mode in the candidate prediction set, use each intra-frame prediction mode to encode and predict the current block, and obtain the first Two encoding costs.
  • the above-mentioned candidate prediction set does not include the intra-frame prediction mode in the MPM.
  • the above-mentioned first predictive value is determined as the target predictive value of the current block.
  • write the code stream after setting the second flag to true for example, set the TIMD enable flag to true, for example, set it to 1 and then code into the code stream.
  • the second flag is set to false and then written into the code stream, for example, the TIMD enable flag is set to false , such as setting it to 0 and encoding it into the code stream.
  • the second flag is used to indicate whether the target prediction value of the current block is determined through at least one of the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the video encoder determines the first intra prediction mode and the second intra prediction mode of the current block; determines the weighted fusion condition of the current block according to the image content of the current sequence, and the weighted fusion condition It is used to judge whether the current block is weighted and predicted by the first intra prediction mode and the second intra prediction mode; according to the weighted fusion condition and at least one of the first intra prediction mode and the second intra prediction mode, determine the current block The first predictive value of the block; according to the first predictive value, determine the target predictive value of the current block.
  • the present application determines the weighted fusion condition of the current block according to the image content of the current sequence, and judges whether to perform weighted fusion prediction on the current block based on the weighted fusion condition, which can avoid the time when weighted fusion prediction is performed on image content that does not require weighted fusion prediction. , reduce the quality of prediction, introduce unnecessary noise problems, and then improve the accuracy of intra prediction.
  • FIG. 11 is a schematic flow chart of an intra prediction method provided in an embodiment of the present application, as shown in FIG. 11 , including:
  • the DIMD permission flag is used to indicate whether the current decoder is allowed to use the DIMD technology.
  • TIMD permission flag indicates that the current decoder allows the use of TIMD technology, and at least one reference reconstruction sample among the multiple reference reconstruction samples of the current block exists, determine the MPM of the current block, and determine the No. 1 reference reconstruction sample of the current block according to the MPM An intra prediction mode and a second intra prediction mode.
  • the first fusion condition of the current block is determined according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode.
  • the first fusion condition is determined according to the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the foregoing first encoding cost is a rate-distortion cost.
  • the first encoding cost is the minimum cost of the first encoding cost and the second encoding cost, determine the first predictive value as the target predictive value of the current block, and set the TIMD enable flag to 1 and program stream.
  • the TIMD enable flag is used to indicate whether the current block uses TIMD technology.
  • the first encoding cost is not the minimum cost among the first encoding cost and the second encoding cost, determine the predicted value corresponding to the smallest second encoding cost as the target predicted value of the current block, and set the TIMD enable flag to Code stream after 0.
  • the weighted fusion condition of the current block is determined, and based on the weighted fusion condition, it is judged whether to perform weighted fusion prediction on the current block. It avoids the problem of reducing the prediction quality and introducing unnecessary noise when weighted fusion prediction is performed on image content that does not require weighted fusion prediction, thereby improving the accuracy of intra-frame prediction.
  • FIGS. 8 to 11 are only examples of the present application, and should not be construed as limiting the present application.
  • sequence numbers of the above-mentioned processes do not mean the order of execution, and the order of execution of the processes should be determined by their functions and internal logic, and should not be used in this application.
  • the implementation of the examples constitutes no limitation.
  • the term "and/or" is only an association relationship describing associated objects, indicating that there may be three relationships. Specifically, A and/or B may mean: A exists alone, A and B exist simultaneously, and B exists alone.
  • the character "/" in this article generally indicates that the contextual objects are an "or" relationship.
  • Fig. 12 is a schematic block diagram of an intra prediction device provided by an embodiment of the present application.
  • the intra prediction device 10 includes:
  • a decoding unit 11 configured to decode a code stream, and determine a first intra-frame prediction mode and a second intra-frame prediction mode of the current block;
  • the determining unit 12 is configured to determine the weighted fusion condition of the current block according to the image content of the current sequence, and the weighted fusion condition is used to judge whether the current block passes the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the prediction unit 13 is configured to determine a target prediction value of the current block according to the weighted fusion condition and at least one of the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the determination unit 12 is specifically configured to decode the code stream to obtain a first flag, the first flag is used to indicate whether to use the first technology, and the first technology is used under the first image content ; Determine the weighted fusion condition of the current block according to the first flag.
  • the determining unit 12 is specifically configured to determine the first fusion condition of the current block if the first flag indicates that the first technology is used; determine the first fusion condition as the current block Weighted fusion condition for blocks.
  • the determination unit 12 is specifically configured to modify the value of the first threshold coefficient to a first preset value, and the first threshold coefficient is used to determine the first fusion condition; according to the first The first cost corresponding to the intra prediction mode, the second cost corresponding to the second intra prediction mode, and the modified first threshold coefficient determine the first fusion condition.
  • the first fusion condition is that the second cost is less than a product of the first cost and the modified first threshold coefficient.
  • the prediction unit 13 is specifically configured to use the first intra prediction mode and the first threshold coefficient if the second cost is less than the product of the first cost and the modified first threshold coefficient
  • the second intra-frame prediction mode is used to determine the target prediction value of the current block.
  • the prediction unit 13 is specifically configured to use the first intra prediction mode if the second cost is greater than or equal to the product of the first cost and the modified first threshold coefficient , to determine the target prediction value of the current block.
  • the first preset value is a positive number less than 2.
  • the determining unit 12 is specifically configured to determine the first fusion condition according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode.
  • the first fusion condition is that at least one of the first cost and the second cost is greater than or equal to a first preset threshold.
  • the prediction unit 13 is specifically configured to use the first intra prediction if at least one of the first cost and the second cost is greater than or equal to the first preset threshold mode and the second intra-frame prediction mode, and determine the target prediction value of the current block.
  • the prediction unit 13 is specifically configured to use the first intra-frame prediction mode to determine the The target predictor for the current block.
  • the determining unit 12 is specifically configured to determine the first fusion condition according to the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the first fusion condition is that the index number difference between the first intra prediction mode and the second intra prediction mode is greater than or equal to a second preset threshold.
  • the prediction unit 13 is specifically configured to use The first intra-frame prediction mode and the second intra-frame prediction mode determine a target prediction value of the current block.
  • the prediction unit 13 is specifically configured to use the The first intra prediction mode is used to determine the target prediction value of the current block.
  • the determining unit 12 is specifically configured to determine according to the image content of the current sequence if at least one of the first intra prediction mode and the second intra prediction mode is an angle prediction mode The weighted fusion condition of the current block.
  • the prediction unit 13 is further configured to determine according to the first intra prediction mode if both the first intra prediction mode and the second intra prediction mode are non-angle prediction modes The target prediction value of the current block.
  • the decoding unit 11 is specifically configured to determine the most probable mode list of the current block: according to the most probable mode list, determine the first intra-frame prediction mode and the second intra-frame prediction mode .
  • the decoding unit 11 is specifically configured to determine a candidate intra-frame prediction mode in the most probable mode list as the first intra-frame prediction mode; A candidate intra-frame prediction mode other than the first intra-frame prediction mode is determined as the second intra-frame prediction mode.
  • the decoding unit 11 is specifically configured to determine the cost when predicting the current block using the candidate intra prediction modes in the most probable mode list; The cost corresponding to the candidate intra-frame prediction mode is used to determine the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the decoding unit 11 is specifically configured to decode the code stream, obtain a template-based intra-frame mode to derive a TIMD enable flag, and the TIMD enable flag is used to indicate whether the current block adopts TIMD technology; if the When the TIMD enable flag indicates that the current block uses the TIMD technology, then determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block.
  • the decoding unit 11 is specifically configured to: if the TIMD enabling flag indicates that the current block uses the TIMD technology technology, and at least one of the multiple reference reconstruction samples of the current block exists, then determine the most probable mode list of the current block: according to the most probable mode list, determine the current block A first intra prediction mode and a second intra prediction mode.
  • the decoding unit 11 is specifically configured to determine to use the candidate intra prediction modes in the most probable mode list if the number of candidate intra prediction modes in the most probable mode list is greater than 1.
  • Prediction mode the cost when predicting the template area of the current block; according to the cost corresponding to the candidate intra-frame prediction mode in the most probable mode list, determine the first intra-frame prediction mode and the second intra-frame prediction model.
  • the decoding unit 11 is specifically configured to determine the prediction value when predicting the template area of the current block using the candidate intra prediction mode in the most probable mode list; according to the candidate frame The prediction value corresponding to the intra prediction mode and the reconstruction value of the template area determine the cost corresponding to the candidate intra prediction mode.
  • the decoding unit 11 is specifically configured to determine the candidate intra-frame prediction mode with the lowest cost in the most probable mode list as the first intra-frame prediction mode; The candidate intra-frame prediction mode with the second lowest cost is determined as the second intra-frame prediction mode.
  • the prediction unit 13 is further configured to use the Planar if the TIMD enable flag indicates that the current block adopts the TIMD technology, and the multiple reference reconstruction samples of the current block do not exist. mode to predict the current block to obtain the target prediction value of the current block.
  • the decoding unit 11 is specifically configured to determine the candidate intra prediction mode with the lowest cost in the most probable mode list as the first initial mode, and determine the candidate intra prediction mode with the second lowest cost in the most probable mode list
  • the candidate intra prediction mode is determined as the second initial mode; if at least one of the first initial mode and the second initial mode is an angle prediction mode, according to the preset offset, the performing offset processing on the angle prediction modes in the first initial mode and the second initial mode to obtain the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the decoding unit 11 is further configured to determine the first initial mode as the first intra prediction mode if neither the first initial mode nor the second initial mode is an angle prediction mode mode, determining the second initial mode as the second intra prediction mode.
  • the decoding unit 11 is further configured to decode the code stream to obtain a second flag, and the second flag is used to indicate whether the current block passes the first intra-frame prediction mode and the second frame At least one of the intra prediction modes determines a target prediction value; if the second flag is true, the first intra prediction mode and the second intra prediction mode are determined.
  • the second flag is a template-based intra mode derivation TIMD enable flag.
  • the determining unit 12 is further configured to determine the type of the current frame where the current block is located; determine whether to determine the current block according to the image content of the current sequence according to the type of the current frame Weighted fusion condition.
  • the determining unit 12 is further configured to determine the weighted fusion condition of the current block according to the image content of the current sequence if the type of the current frame is a target frame type.
  • the target frame type includes at least one of an I frame, a P frame, and a B frame.
  • the determining unit 12 is further configured to determine the type of the current frame where the current block is located, and the size of the current block;
  • the type of the current frame and the size of the current block determine whether to determine the weighted fusion condition of the current block according to the image content of the current sequence.
  • the determining unit 12 is further configured to determine according to the image content of the current sequence if the type of the current frame is the first frame type and the size of the current block is greater than a first threshold The weighted fusion condition of the current block; if the type of the current frame is the second frame type, and the size of the current block is greater than a second threshold, then determine the current block according to the image content of the current sequence The weighted fusion condition of .
  • the second threshold is different from the first threshold if the first frame type is an I frame and the second frame type is a B frame or a P frame.
  • the determining unit 12 is further configured to determine a quantization parameter corresponding to the current block; determine whether to determine a weighted fusion condition of the current block according to the image content of the current sequence according to the quantization parameter.
  • the determining unit 12 is further configured to determine the weighted fusion condition of the current block according to the image content of the current sequence if the quantization parameter is smaller than a third threshold.
  • the first flag multiplexes the third flag of the current sequence.
  • the third flag is a sequence-level IBC enable flag or a template matching prediction TMP enable flag.
  • the device embodiment and the method embodiment may correspond to each other, and similar descriptions may refer to the method embodiment. To avoid repetition, details are not repeated here.
  • the device 10 shown in FIG. 12 can execute the intra-frame prediction method of the embodiment of the present application, and the aforementioned and other operations and/or functions of each unit in the device 10 are to implement the above-mentioned intra-frame prediction method and other methods. For the sake of brevity, the corresponding process will not be repeated here.
  • Fig. 13 is a schematic block diagram of an intra prediction device provided by an embodiment of the present application.
  • the intra prediction device 20 may include:
  • the first determining unit 21 is configured to determine a first intra-frame prediction mode and a second intra-frame prediction mode of the current block;
  • the second determining unit 22 is configured to determine the weighted fusion condition of the current block according to the image content of the current sequence, and the weighted fusion condition is used to judge whether the current block passes the first intra prediction mode and the performing weighted prediction in the second intra prediction mode;
  • a prediction unit 23 configured to determine a first predictive value of the current block according to the weighted fusion condition and at least one of the first intra-frame prediction mode and the second intra-frame prediction mode; according to the The first prediction value is to determine the target prediction value of the current block.
  • the second determination unit 22 is specifically configured to determine the first fusion condition of the current block if the image content of the current sequence is the first image content; determine the first fusion condition is the weighted fusion condition of the current block.
  • the prediction unit 23 is further configured to write a first flag into the code stream, the first flag is used to indicate whether to use the first technology, and the first technology is used under the first image content .
  • the second determination unit 22 is specifically configured to modify the value of the first threshold coefficient to a first preset value, and the first threshold coefficient is used to determine the first fusion condition; according to the The first cost corresponding to the first intra prediction mode, the second cost corresponding to the second intra prediction mode, and the modified first threshold coefficient determine the first fusion condition.
  • the first fusion condition is that the second cost is less than a product of the first cost and the modified first threshold coefficient.
  • the prediction unit 23 is specifically configured to use the first intra prediction mode and the first threshold coefficient if the second cost is less than the product of the first cost and the modified first threshold coefficient
  • the second intra-frame prediction mode is used to determine the first prediction value of the current block.
  • the prediction unit 23 is specifically configured to use the first intra-frame prediction mode if the second cost is greater than or equal to the product of the first cost and the modified first threshold coefficient , to determine the first prediction value of the current block.
  • the first preset value is a positive number less than 2.
  • the second determining unit 22 is specifically configured to determine the first blending method according to the first cost corresponding to the first intra prediction mode and the second cost corresponding to the second intra prediction mode. condition.
  • the first fusion condition is that at least one of the first cost and the second cost is greater than or equal to a first preset threshold.
  • the prediction unit 23 is specifically configured to use the first intra prediction if at least one of the first cost and the second cost is greater than or equal to the first preset threshold mode and the second intra-frame prediction mode, and determine the first prediction value of the current block.
  • the prediction unit 23 is specifically configured to use the first intra-frame prediction mode to determine the The first predictor of the current block.
  • the second determining unit 22 is specifically configured to determine the first fusion condition according to the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the first fusion condition is that a difference between index numbers of the first intra-frame prediction mode and the second intra-frame prediction mode is greater than or equal to a second preset threshold.
  • the prediction unit 23 is specifically configured to use The first intra-frame prediction mode and the second intra-frame prediction mode determine a first prediction value of the current block.
  • the prediction unit 23 is specifically configured to use the The first intra-frame prediction mode is used to determine the first prediction value of the current block.
  • the second determination unit 22 is specifically configured to: if at least one of the first intra-frame prediction mode and the second intra-frame prediction mode is an angle prediction mode, according to the image content of the current sequence , to determine the weighted fusion condition of the current block.
  • the prediction unit 23 is further configured to determine according to the first intra prediction mode if both the first intra prediction mode and the second intra prediction mode are non-angle prediction modes The first predicted value of the current block.
  • the first determination unit 21 is specifically configured to acquire the most probable mode list of the current block: determine the first intra-frame prediction mode and the second intra-frame prediction mode according to the most probable mode list predictive mode.
  • the first determining unit 21 is specifically configured to determine a candidate intra-frame prediction mode in the most probable mode list as the first intra-frame prediction mode; A candidate intra-frame prediction mode in the list other than the first intra-frame prediction mode is determined as the second intra-frame prediction mode.
  • the first determining unit 21 is specifically configured to determine the cost when predicting the current block using the candidate intra prediction modes in the most probable mode list; according to the most probable mode The costs corresponding to the candidate intra-frame prediction modes in the list are used to determine the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the first determining unit 21 is specifically configured to acquire a template-based intra mode derived TIMD permission flag, where the TIMD permission flag is used to indicate whether the current sequence is allowed to use the TIMD technology; if When the TIMD allowable flag indicates that the current sequence is allowed to use the TIMD technology, then determine the first intra-frame prediction mode and the second intra-frame prediction mode of the current block.
  • the first determining unit 21 is specifically configured to: if the TIMD allowed flag indicates that the current sequence allows When the TIMD technique is used, and at least one reference reconstruction sample among the plurality of reference reconstruction samples of the current block exists, obtain the most probable mode list of the current block: determine the most probable mode list according to the most probable mode list The first intra-frame prediction mode and the second intra-frame prediction mode of the current block.
  • the first determining unit 21 is specifically configured to, if the number of candidate intra prediction modes in the most probable mode list list is greater than 1, determine to use the The candidate intra prediction mode is the cost when predicting the template area of the current block; according to the cost corresponding to the candidate intra prediction mode in the most probable mode list, the first intra prediction mode and the second intra prediction mode are determined. Intra prediction mode.
  • the first determining unit 21 is specifically configured to determine the prediction value when predicting the template area of the current block using the candidate intra prediction modes in the most probable mode list; according to the The prediction value corresponding to the candidate intra prediction mode and the reconstruction value of the template area determine the cost corresponding to the candidate intra prediction mode.
  • the first determining unit 21 is specifically configured to determine the candidate intra-frame prediction mode with the lowest cost in the most probable mode list as the first intra-frame prediction mode; A candidate intra-frame prediction mode with the second lowest cost in the mode list is determined as the second intra-frame prediction mode.
  • the prediction unit 23 is further configured to use The Planar mode predicts the current block to obtain a first prediction value of the current block.
  • the first determining unit 21 is further configured to determine the candidate intra prediction mode with the smallest cost in the most probable mode list as the first initial mode, and set the cost in the most probable mode list to The second smallest candidate intra prediction mode is determined as the second initial mode; if at least one of the first initial mode and the second initial mode is an angle prediction mode, according to the preset offset, the Perform offset processing on the angle prediction modes in the first initial mode and the second initial mode to obtain the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the first determining unit 21 is further configured to determine the first initial mode as the first frame if neither the first initial mode nor the second initial mode is an angle prediction mode
  • the intra prediction mode is to determine the second initial mode as the second intra prediction mode.
  • the prediction unit 23 is specifically configured to determine the first encoding cost corresponding to the first predictive value according to the first predictive value; A second coding cost when performing prediction: determining a prediction value corresponding to a minimum coding cost among the first coding cost and the second coding cost as the target prediction value of the current block.
  • the prediction unit 23 is further configured to set the second flag to be true and then write the code stream if the first encoding cost is the minimum encoding cost of the first encoding cost and the second encoding cost; If the first encoding cost is not the minimum encoding cost among the first encoding cost and the second encoding cost, set the second flag to be false and write it into the code stream; wherein the second flag is used to indicate the Whether the target prediction value of the current block is determined by at least one of the first intra-frame prediction mode and the second intra-frame prediction mode.
  • the second flag is a template-based intra mode derivation TIMD enable flag.
  • the second determination unit 22 is further configured to determine the type of the current frame where the current block is located; according to the type of the current frame, determine whether to determine the current block according to the image content of the current sequence Weighted fusion condition for blocks.
  • the second determination unit 22 is further configured to determine the weighted fusion condition of the current block according to the image content of the current sequence if the type of the current frame is the target frame type.
  • the target frame type includes at least one of an I frame, a P frame, and a B frame.
  • the second determining unit 22 is further configured to determine the type of the current frame where the current block is located, and the size of the current block; according to the type of the current frame and the size of the current block, Determine whether to determine the weighted fusion condition of the current block according to the image content of the current sequence.
  • the second determination unit 22 is further configured to: if the type of the current frame is the first frame type and the size of the current block is larger than the first threshold, then according to the image content of the current sequence , determine the weighted fusion condition of the current block; if the type of the current frame is the second frame type, and the size of the current block is greater than a second threshold, then according to the image content of the current sequence, determine the The weighted fusion condition for the current block.
  • the second threshold is different from the first threshold if the first frame type is an I frame and the second frame type is a B frame or a P frame.
  • the second determination unit 22 is also used to determine the quantization parameter corresponding to the current block; according to the quantization parameter, determine whether to determine the weighted fusion of the current block according to the image content of the current sequence condition.
  • the second determination unit 22 is further configured to determine the weighted fusion condition of the current block according to the image content of the current sequence if the quantization parameter is smaller than a third threshold.
  • the first flag multiplexes the third flag of the current sequence.
  • the third flag is a sequence-level IBC enable flag or a template matching prediction TMP enable flag.
  • the prediction unit 23 is further configured to write the first flag into the code stream.
  • the device embodiment and the method embodiment may correspond to each other, and similar descriptions may refer to the method embodiment. To avoid repetition, details are not repeated here.
  • the device 20 shown in FIG. 13 may correspond to the corresponding subject in the intra prediction method of the embodiment of the present application, and the aforementioned and other operations and/or functions of each unit in the device 20 are for realizing the encoding method, etc. For the sake of brevity, the corresponding processes in each method are not repeated here.
  • the functional unit may be implemented in the form of hardware, may also be implemented by instructions in the form of software, and may also be implemented by a combination of hardware and software units.
  • each step of the method embodiment in the embodiment of the present application can be completed by an integrated logic circuit of the hardware in the processor and/or instructions in the form of software, and the steps of the method disclosed in the embodiment of the present application can be directly embodied as hardware
  • the decoding processor is executed, or the combination of hardware and software units in the decoding processor is used to complete the execution.
  • the software unit may be located in a mature storage medium in the field such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, and registers.
  • the storage medium is located in the memory, and the processor reads the information in the memory, and completes the steps in the above method embodiments in combination with its hardware.
  • Fig. 14 is a schematic block diagram of an electronic device provided by an embodiment of the present application.
  • the electronic device 30 may be the video encoder or video decoder described in the embodiment of the present application, and the electronic device 30 may include:
  • a memory 33 and a processor 32 the memory 33 is used to store a computer program 34 and transmit the program code 34 to the processor 32 .
  • the processor 32 can call and run the computer program 34 from the memory 33 to implement the method in the embodiment of the present application.
  • the processor 32 can be used to execute the steps in the above-mentioned method 200 according to the instructions in the computer program 34 .
  • the processor 32 may include, but is not limited to:
  • DSP Digital Signal Processor
  • ASIC Application Specific Integrated Circuit
  • FPGA Field Programmable Gate Array
  • the memory 33 includes but is not limited to:
  • non-volatile memory can be read-only memory (Read-Only Memory, ROM), programmable read-only memory (Programmable ROM, PROM), erasable programmable read-only memory (Erasable PROM, EPROM), electronically programmable Erase Programmable Read-Only Memory (Electrically EPROM, EEPROM) or Flash.
  • the volatile memory can be Random Access Memory (RAM), which acts as external cache memory.
  • RAM Static Random Access Memory
  • SRAM Static Random Access Memory
  • DRAM Dynamic Random Access Memory
  • Synchronous Dynamic Random Access Memory Synchronous Dynamic Random Access Memory
  • SDRAM double data rate synchronous dynamic random access memory
  • Double Data Rate SDRAM, DDR SDRAM double data rate synchronous dynamic random access memory
  • Enhanced SDRAM, ESDRAM enhanced synchronous dynamic random access memory
  • SLDRAM synchronous connection dynamic random access memory
  • Direct Rambus RAM Direct Rambus RAM
  • the computer program 34 can be divided into one or more units, and the one or more units are stored in the memory 33 and executed by the processor 32 to complete the present application.
  • the one or more units may be a series of computer program instruction segments capable of accomplishing specific functions, and the instruction segments are used to describe the execution process of the computer program 34 in the electronic device 30 .
  • the electronic device 30 may also include:
  • a transceiver 33 the transceiver 33 can be connected to the processor 32 or the memory 33 .
  • the processor 32 can control the transceiver 33 to communicate with other devices, specifically, can send information or data to other devices, or receive information or data sent by other devices.
  • Transceiver 33 may include a transmitter and a receiver.
  • the transceiver 33 may further include antennas, and the number of antennas may be one or more.
  • bus system includes not only a data bus, but also a power bus, a control bus and a status signal bus.
  • Fig. 15 is a schematic block diagram of a video codec system provided by an embodiment of the present application.
  • the video codec system 40 may include: a video encoder 41 and a video decoder 42, wherein the video encoder 41 is used to execute the video encoding method involved in the embodiment of the present application, and the video decoder 42 is used to execute The video decoding method involved in the embodiment of the present application.
  • the present application also provides a computer storage medium, on which a computer program is stored, and when the computer program is executed by a computer, the computer can execute the methods of the above method embodiments.
  • the embodiments of the present application further provide a computer program product including instructions, and when the instructions are executed by a computer, the computer executes the methods of the foregoing method embodiments.
  • the present application also provides a code stream, which is generated by the above coding method.
  • the code stream includes the first flag.
  • the computer program product includes one or more computer instructions.
  • the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device.
  • the computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, e.g. (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) to another website site, computer, server or data center.
  • the computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server or a data center integrated with one or more available media.
  • the available medium may be a magnetic medium (such as a floppy disk, a hard disk, or a magnetic tape), an optical medium (such as a digital video disc (digital video disc, DVD)), or a semiconductor medium (such as a solid state disk (solid state disk, SSD)), etc.
  • the disclosed systems, devices and methods may be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components can be combined or can be Integrate into another system, or some features may be ignored, or not implemented.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.
  • a unit described as a separate component may or may not be physically separated, and a component displayed as a unit may or may not be a physical unit, that is, it may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit.

Abstract

本申请提供一种帧内预测方法、设备、系统、及存储介质，通过确定当前块的第一帧内预测模式和第二帧内预测模式；根据当前序列的图像内容，确定当前块的加权融合条件，加权融合条件用于判断当前块是否通过第一帧内预测模式和第二帧内预测模式进行加权预测；根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的目标预测值。即本申请根据当前序列的图像内容，确定当前块的加权融合条件，并基于该加权融合条件判断是否对当前块进行加权融合预测，可以避免对不需要加权融合预测的图像内容进行加权融合预测时，降低预测质量，引入不必要噪声的问题，进而提高了帧内预测的准确性。

Description

帧内预测方法、设备、系统、及存储介质 技术领域
本申请涉及视频编解码技术领域，尤其涉及一种帧内预测方法、设备、系统、及存储介质。
背景技术
数字视频技术可以并入多种视频装置中，例如数字电视、智能手机、计算机、电子阅读器或视频播放器等。随着视频技术的发展，视频数据所包括的数据量较大，为了便于视频数据的传输，视频装置执行视频压缩技术，以使视频数据更加有效的传输或存储。
视频通过编码实现压缩，其编码过程包括预测、变换和量化等过程。例如，通过帧内预测和/或帧间预测，确定当前块的预测块，当前块减去预测块得到残差块，对残差块进行变换得到变换系数，对变换系数进行量化得到量化系数，并对量化系数进行编码，形成码流。
为了提高帧内预测的准确性，可以采用两种或多种帧内预测模式对当前块进行加权融合预测，得到当前块的预测值。但是，在一些情况下，例如录制的屏幕内容，采用多种帧内预测模式对当前块进行加权融合预测时，反而会降低预测质量。
发明内容
本申请实施例提供了一种帧内预测方法、设备、系统、及存储介质，基于图像内容来确定是否进行加权融合预测，实现差异化的加权融合预测，进而提高了帧内预测的准确性。
第一方面，本申请提供了一种帧内预测方法，包括：
解码码流，确定当前块的第一帧内预测模式和第二帧内预测模式；
根据当前序列的图像内容，确定所述当前块的加权融合条件，所述加权融合条件用于判断所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式进行加权预测；
根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值。
第二方面，本申请实施例提供一种帧内预测方法，包括：
确定当前块的第一帧内预测模式和第二帧内预测模式；
根据当前序列的图像内容，确定所述当前块的加权融合条件，所述加权融合条件用于判断所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式进行加权预测；
根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值；
根据所述第一预测值，确定所述当前块的目标预测值。
第三方面，本申请提供了一种帧内预测装置，用于执行上述第一方面或其各实现方式中的方法。具体地，该编码器包括用于执行上述第一方面或其各实现方式中的方法的功能单元。
第四方面，本申请提供了一种帧内预测装置，用于执行上述第二方面或其各实现方式中的方法。具体地，该解码器包括用于执行上述第二方面或其各实现方式中的方法的功能单元。
第五方面，提供了一种视频编码器，包括处理器和存储器。该存储器用于存储计算机程序，该处理器用于调用并运行该存储器中存储的计算机程序，以执行上述第一方面或其各实现方式中的方法。
第六方面，提供了一种视频解码器，包括处理器和存储器。该存储器用于存储计算机程序，该处理器用于调用并运行该存储器中存储的计算机程序，以执行上述第二方面或其各实现方式中的方法。
第七方面，提供了一种视频编解码系统，包括视频编码器和视频解码器。视频编码器用于执行上述第一方面或其各实现方式中的方法，视频解码器用于执行上述第二方面或其各实现方式中的方法。
第八方面，提供了一种芯片，用于实现上述第一方面至第二方面中的任一方面或其各实现方式中的方法。具体地，该芯片包括：处理器，用于从存储器中调用并运行计算机程序，使得安装有该芯片的设备执行如上述第一方面至第二方面中的任一方面或其各实现方式中的方法。
第九方面，提供了一种计算机可读存储介质，用于存储计算机程序，该计算机程序使得计算机执行上述第一方面至第二方面中的任一方面或其各实现方式中的方法。
第十方面，提供了一种计算机程序产品，包括计算机程序指令，该计算机程序指令使得计算机执行上述第一方面至第二方面中的任一方面或其各实现方式中的方法。
第十一方面，提供了一种计算机程序，当其在计算机上运行时，使得计算机执行上述第一方面至第二方面中的任一方面或其各实现方式中的方法。
第十二方面，提供了一种码流，该码流是通过上述第一方面中的任一方面或其各实现方式生成的。
基于以上技术方案，通过解码码流，确定当前块的第一帧内预测模式和第二帧内预测模式；根据当前序列的图像内容，确定当前块的加权融合条件，加权融合条件用于判断当前块是否通过第一帧内预测模式和第二帧内预测模式进行加权预测；根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的目标预测值。即本申请根据当前序列的图像内容，确定当前块的加权融合条件，并基于该加权融合条件判断是否对当前块进行加权融合预测，可以避免对不需要加权融合预测的图像内容进行加权融合预测时，降低预测质量，引入不必要噪声的问题，进而提高了帧内预测的准确性。
附图说明
图1为本申请实施例涉及的一种视频编解码系统的示意性框图；
图2是本申请实施例涉及的视频编码器的示意性框图；
图3是本申请实施例涉及的视频解码器的示意性框图；
图4是一种帧内预测模式示意图；
图5是一种帧内预测模式示意图；
图6是一种帧内预测模式示意图；
图7为TIMD的预测示意图；
图8为本申请实施例提供的帧内预测方法的一种流程示意图；
图9为本申请实施例提供的帧内预测方法的一种流程示意图；
图10为本申请实施例提供的帧内预测方法的一种流程示意图；
图11为本申请实施例提供的帧内预测方法的一种流程示意图；
图12是本申请一实施例提供的帧内预测装置的示意性框图；
图13是本申请一实施例提供的帧内预测装置的示意性框图；
图14是本申请实施例提供的电子设备的示意性框图；
图15是本申请实施例提供的视频编解码系统的示意性框图。
具体实施方式
本申请可应用于图像编解码领域、视频编解码领域、硬件视频编解码领域、专用电路视频编解码领域、实时视频编解码领域等。例如，本申请的方案可结合至音视频编码标准(audio video coding standard，简称AVS)，例如，H.264/音视频编码(audio video coding，简称AVC)标准，H.265/高效视频编码(high efficiency video coding，简称HEVC)标准以及H.266/多功能视频编码(versatile video coding，简称VVC)标准。或者，本申请的方案可结合至其它专属或行业标准而操作，所述标准包含ITU-TH.261、ISO/IECMPEG-1Visual、ITU-TH.262或ISO/IECMPEG-2Visual、ITU-TH.263、ISO/IECMPEG-4Visual，ITU-TH.264(还称为ISO/IECMPEG-4AVC)，包含可分级视频编解码(SVC)及多视图视频编解码(MVC)扩展。应理解，本申请的技术不限于任何特定编解码标准或技术。
为了便于理解，首先结合图1对本申请实施例涉及的视频编解码系统进行介绍。
图1为本申请实施例涉及的一种视频编解码系统的示意性框图。需要说明的是，图1只是一种示例，本申请实施例的视频编解码系统包括但不限于图1所示。如图1所示，该视频编解码系统100包含编码设备110和解码设备120。其中编码设备用于对视频数据进行编码(可以理解成压缩)产生码流，并将码流传输给解码设备。解码设备对编码设备编码产生的码流进行解码，得到解码后的视频数据。
本申请实施例的编码设备110可以理解为具有视频编码功能的设备，解码设备120可以理解为具有视频解码功能的设备，即本申请实施例对编码设备110和解码设备120包括更广泛的装置，例如包含智能手机、台式计算机、移动计算装置、笔记本(例如，膝上型)计算机、平板计算机、机顶盒、电视、相机、显示装置、数字媒体播放器、视频游戏控制台、车载计算机等。
在一些实施例中，编码设备110可以经由信道130将编码后的视频数据(如码流)传输给解码设备120。信道130可以包括能够将编码后的视频数据从编码设备110传输到解码设备120的一个或多个媒体和/或装置。
在一个实例中，信道130包括使编码设备110能够实时地将编码后的视频数据直接发射到解码设备120的一个或多个通信媒体。在此实例中，编码设备110可根据通信标准来调制编码后的视频数据，且将调制后的视频数据发射到解码设备120。其中通信媒体包含无线通信媒体，例如射频频谱，可选的，通信媒体还可以包含有线通信媒体，例如一根或多根物理传输线。
在另一实例中，信道130包括存储介质，该存储介质可以存储编码设备110编码后的视频数据。存储介质包含多种本地存取式数据存储介质，例如光盘、DVD、快闪存储器等。在该实例中，解码设备120可从该存储介质中获取编码后的视频数据。
在另一实例中，信道130可包含存储服务器，该存储服务器可以存储编码设备110编码后的视频数据。在此实例中，解码设备120可以从该存储服务器中下载存储的编码后的视频数据。可选的，该存储服务器可以存储编码后的视频数据且可以将该编码后的视频数据发射到解码设备120，例如web服务器(例如，用于网站)、文件传送协议(FTP)服务器等。
一些实施例中，编码设备110包含视频编码器112及输出接口113。其中，输出接口113可以包含调制器/解调器(调制解调器)和/或发射器。
在一些实施例中，编码设备110除了包括视频编码器112和输入接口113外，还可以包括视频源111。
视频源111可包含视频采集装置(例如，视频相机)、视频存档、视频输入接口、计算机图形系统中的至少一个，其中，视频输入接口用于从视频内容提供者处接收视频数据，计算机图形系统用于产生视频数据。
视频编码器112对来自视频源111的视频数据进行编码，产生码流。视频数据可包括一个或多个图像(picture)或图像序列(sequence of pictures)。码流以比特流的形式包含了图像或图像序列的编码信息。编码信息可以包含编码图像数据及相关联数据。相关联数据可包含序列参数集(sequence parameter set，简称SPS)、图像参数集(picture parameter set，简称PPS)及其它语法结构。SPS可含有应用于一个或多个序列的参数。PPS可含有应用于一个或多个图像的参数。语法结构是指码流中以指定次序排列的零个或多个语法元素的集合。
视频编码器112经由输出接口113将编码后的视频数据直接传输到解码设备120。编码后的视频数据还可存储于存储介质或存储服务器上，以供解码设备120后续读取。
在一些实施例中，解码设备120包含输入接口121和视频解码器122。
在一些实施例中，解码设备120除包括输入接口121和视频解码器122外，还可以包括显示装置123。
其中，输入接口121包含接收器及/或调制解调器。输入接口121可通过信道130接收编码后的视频数据。
视频解码器122用于对编码后的视频数据进行解码，得到解码后的视频数据，并将解码后的视频数据传输至显示装置123。
显示装置123显示解码后的视频数据。显示装置123可与解码设备120整合或在解码设备120外部。显示装置123可包括多种显示装置，例如液晶显示器(LCD)、等离子体显示器、有机发光二极管(OLED)显示器或其它类型的显示装置。
此外，图1仅为实例，本申请实施例的技术方案不限于图1，例如本申请的技术还可以应用于单侧的视频编码或单侧的视频解码。
下面对本申请实施例涉及的视频编码框架进行介绍。
图2是本申请实施例涉及的视频编码器的示意性框图。应理解，该视频编码器200可用于对图像进行有损压缩(lossy compression)，也可用于对图像进行无损压缩(lossless compression)。该无损压缩可以是视觉无损压缩(visually lossless compression)，也可以是数学无损压缩(mathematically lossless compression)。
该视频编码器200可应用于亮度色度(YCbCr，YUV)格式的图像数据上。例如，YUV比例可以为4:2:0、4:2:2或者4:4:4，Y表示明亮度(Luma)，Cb(U)表示蓝色色度，Cr(V)表示红色色度，U和V表示为色度(Chroma)用于描述色彩及饱和度。例如，在颜色格式上，4:2:0表示每4个像素有4个亮度分量，2个色度分量(YYYYCbCr)，4:2:2表示每4个像素有4个亮度分量，4个色度分量(YYYYCbCrCbCr)，4:4:4表示全像素显示(YYYYCbCrCbCrCbCrCbCr)。
例如，该视频编码器200读取视频数据，针对视频数据中的每帧图像，将一帧图像划分成若干个编码树单元(coding tree unit，CTU)，在一些例子中，CTB可被称作“树型块”、“最大编码单元”(Largest Coding unit，简称LCU)或“编码树型块”(coding tree block，简称CTB)。每一个CTU可以与图像内的具有相等大小的像素块相关联。每一像素可对应一个亮度(luminance或luma)采样及两个色度(chrominance或chroma)采样。因此，每一个CTU可与一个亮度采样块及两个色度采样块相关联。一个CTU大小例如为128×128、64×64、32×32等。一个CTU又可以继续被划分成若干个编码单元(Coding Unit，CU)进行编码，CU可以为矩形块也可以为方形块。CU可以进一步划分为预测单元(prediction Unit，简称PU)和变换单元(transform unit，简称TU)，进而使得编码、预测、变换分离，处理的时候更灵活。在一种示例中，CTU以四叉树方式划分为CU，CU以四叉树方式划分为TU、PU。
视频编码器及视频解码器可支持各种PU大小。假定特定CU的大小为2N×2N，视频编码器及视频解码器可支持2N×2N或N×N的PU大小以用于帧内预测，且支持2N×2N、2N×N、N×2N、N×N或类似大小的对称PU以用于帧间预测。视频编码器及视频解码器还可支持2N×nU、2N×nD、nL×2N及nR×2N的不对称PU以用于帧间预测。
在一些实施例中，如图2所示，该视频编码器200可包括：预测单元210、残差单元220、变换/量化单元230、反变换/量化单元240、重建单元250、环路滤波单元260、解码图像缓存270和熵编码单元280。需要说明的是，视频编码器200可包含更多、更少或不同的功能组件。
可选的，在本申请中，当前块(current block)可以称为当前编码单元(CU)或当前预测单元(PU)等。预测块也可称为预测图像块或图像预测块，重建图像块也可称为重建块或图像重建图像块。
在一些实施例中，预测单元210包括帧间预测单元211和帧内估计单元212。由于视频的一个帧中的相邻像素之间存在很强的相关性，在视频编解码技术中使用帧内预测的方法消除相邻像素之间的空间冗余。由于视频中的相邻帧之间存在着很强的相似性，在视频编解码技术中使用帧间预测方法消除相邻帧之间的时间冗余，从而提高编码效率。
帧间预测单元211可用于帧间预测，帧间预测可以参考不同帧的图像信息，帧间预测使用运动信息从参考帧中找到参考块，根据参考块生成预测块，用于消除时间冗余；帧间预测所使用的帧可以为P帧和/或B帧，P帧指的是向前预测帧，B帧指的是双向预测帧。运动信息包括参考帧所在的参考帧列表，参考帧索引，以及运动矢量。运动矢量可以是整像素的或者是分像素的，如果运动矢量是分像素的，那么需要再参考帧中使用插值滤波做出所需的分像素的块，这里把根据运动矢量找到的参考帧中的整像素或者分像素的块叫参考块。有的技术会直接把参考块作为预测块，有的技术会在参考块的基础上再处理生成预测块。在参考块的基础上再处理生成预测块也可以理解为把参考块作为预测块然后再在预测块的基础上处理生成新的预测块。
帧内估计单元212只参考同一帧图像的信息，预测当前码图像块内的像素信息，用于消除空间冗余。帧内预测所使用的帧可以为I帧。例如对于4×4的当前块，当前块左边一行和上面一列的像素为当前块的参考像素，帧内预测使用这些参考像素对当前块进行预测。这些参考像素可能已经全部可得，即全部已经编解码。也可能有部分不可得，比如当前块是整帧的最左侧，那么当前块的左边的参考像素不可得。或者编解码当前块时，当前块左下方的部分还没有编解码，那么左下方的参考像素也不可得。对于参考像素不可得的情况，可以使用可得的参考像素或某些值或某些方法进行填充，或者不进行填充。
帧内预测有多种预测模式，例如，图4为帧内预测模式的示意图，如图4所示，如HEVC使用的帧内预测模式有Planar、DC和33种角度模式共35种预测模式。图5为帧内预测模式的示意图，如图5所示，VVC使用的帧内模式有Planar、DC和65种角度模式共67种预测模式。图6为帧内预测模式的示意图，如图6所示，AVS3使用DC、Planar、Bilinear和63种角度模式共66种预测模式
需要说明的是，随着角度模式的增加，帧内预测将会更加精确，也更加符合对高清以及超高清数字视频发展的需求。
残差单元220可基于CU的像素块及CU的PU的预测块来产生CU的残差块。举例来说，残差单元220可产生CU的残差块，使得残差块中的每一采样具有等于以下两者之间的差的值：CU的像素块中的采样，及CU的PU的预测块中的对应采样。
变换/量化单元230可量化变换系数。变换/量化单元230可基于与CU相关联的量化参数(QP)值来量化与CU的TU相关联的变换系数。视频编码器200可通过调整与CU相关联的QP值来调整应用于与CU相关联的变换系数的量 化程度。
反变换/量化单元240可分别将逆量化及逆变换应用于量化后的变换系数，以从量化后的变换系数重建残差块。
重建单元250可将重建后的残差块的采样加到预测单元210产生的一个或多个预测块的对应采样，以产生与TU相关联的重建图像块。通过此方式重建CU的每一个TU的采样块，视频编码器200可重建CU的像素块。
环路滤波单元260可执行消块滤波操作以减少与CU相关联的像素块的块效应。
在一些实施例中，环路滤波单元260包括去块滤波单元和样点自适应补偿/自适应环路滤波(SAO/ALF)单元，其中去块滤波单元用于去方块效应，SAO/ALF单元用于去除振铃效应。
解码图像缓存270可存储重建后的像素块。帧间预测单元211可使用含有重建后的像素块的参考图像来对其它图像的PU执行帧间预测。另外，帧内估计单元212可使用解码图像缓存270中的重建后的像素块来对在与CU相同的图像中的其它PU执行帧内预测。
熵编码单元280可接收来自变换/量化单元230的量化后的变换系数。熵编码单元280可对量化后的变换系数执行一个或多个熵编码操作以产生熵编码后的数据。
图3是本申请实施例涉及的视频解码器的示意性框图。
如图3所示，视频解码器300包含：熵解码单元310、预测单元320、反量化/变换单元330、重建单元340、环路滤波单元350及解码图像缓存360。需要说明的是，视频解码器300可包含更多、更少或不同的功能组件。
视频解码器300可接收码流。熵解码单元310可解析码流以从码流提取语法元素。作为解析码流的一部分，熵解码单元310可解析码流中的经熵编码后的语法元素。预测单元320、反量化/变换单元330、重建单元340及环路滤波单元350可根据从码流中提取的语法元素来解码视频数据，即产生解码后的视频数据。
在一些实施例中，预测单元320包括帧间预测单元321和帧内估计单元322。
帧内估计单元322(也称为帧内预测单元)可执行帧内预测以产生PU的预测块。帧内估计单元322可使用帧内预测模式以基于空间相邻PU的像素块来产生PU的预测块。帧内估计单元322还可根据从码流解析的一个或多个语法元素来确定PU的帧内预测模式。
帧间预测单元321可根据从码流解析的语法元素来构造第一参考图像列表(列表0)及第二参考图像列表(列表1)。此外，如果PU使用帧间预测编码，则熵解码单元310可解析PU的运动信息。帧间预测单元321可根据PU的运动信息来确定PU的一个或多个参考块。帧间预测单元321可根据PU的一个或多个参考块来产生PU的预测块。
反量化/变换单元330(也称为反量化/变换单元)可逆量化(即，解量化)与TU相关联的变换系数。反量化/变换单元330可使用与TU的CU相关联的QP值来确定量化程度。
在逆量化变换系数之后，反量化/变换单元330可将一个或多个逆变换应用于逆量化变换系数，以便产生与TU相关联的残差块。
重建单元340使用与CU的TU相关联的残差块及CU的PU的预测块以重建CU的像素块。例如，重建单元340可将残差块的采样加到预测块的对应采样以重建CU的像素块，得到重建图像块。
环路滤波单元350可执行消块滤波操作以减少与CU相关联的像素块的块效应。
视频解码器300可将CU的重建图像存储于解码图像缓存360中。视频解码器300可将解码图像缓存360中的重建图像作为参考图像用于后续预测，或者，将重建图像传输给显示装置呈现。
由上述图2和图3可知，视频编解码的基本流程如下：在编码端，将一帧图像划分成块，对当前块，预测单元210使用帧内预测或帧间预测产生当前块的预测块。残差单元220可基于预测块与当前块的原始块计算残差块，例如将当前块的原始块减去预测块得到残差块，该残差块也可称为残差信息。该残差块经由变换/量化单元230变换与量化等过程，可以去除人眼不敏感的信息，以消除视觉冗余。可选的，经过变换/量化单元230变换与量化之前的残差块可称为时域残差块，经过变换/量化单元230变换与量化之后的时域残差块可称为频率残差块或频域残差块。熵编码单元280接收到变换量化单元230输出的量化后的变换系数，可对该量化后的变换系数进行熵编码，输出码流。例如，熵编码单元280可根据目标上下文模型以及二进制码流的概率信息消除字符冗余。
在解码端，熵解码单元310可解析码流得到当前块的预测信息、量化系数矩阵等，预测单元320基于预测信息对当前块使用帧内预测或帧间预测产生当前块的预测块。反量化/变换单元330使用从码流得到的量化系数矩阵，对量化系数矩阵进行反量化、反变换得到残差块。重建单元340将预测块和残差块相加得到重建块。重建块组成重建图像，环路滤波单元350基于图像或基于块对重建图像进行环路滤波，得到解码图像。编码端同样需要和解码端类似的操作获得解码图像。该解码图像也可以称为重建图像，重建图像可以为后续的帧作为帧间预测的参考帧。
需要说明的是，编码端确定的块划分信息，以及预测、变换、量化、熵编码、环路滤波等模式信息或者参数信息等在必要时携带在码流中。解码端通过解析码流及根据已有信息进行分析确定与编码端相同的块划分信息，预测、变换、量化、熵编码、环路滤波等模式信息或者参数信息，从而保证编码端获得的解码图像和解码端获得的解码图像相同。
当前块(current block)可以是当前编码单元(CU)或当前预测单元(PU)等。
上述是基于块的混合编码框架下的视频编解码器的基本流程，随着技术的发展，该框架或流程的一些模块或步骤可能会被优化，本申请适用于该基于块的混合编码框架下的视频编解码器的基本流程，但不限于该框架及流程。
由上述可知编码时，通用的混合编码框架会先进行预测，预测利用空间或者时间上的相关性能得到一个跟当前块相同或相似的图像。对一个块来说，预测块和当前块是完全相同的情况是有可能出现的，但是很难保证一个视频中的所有块都如此，特别是对自然视频，或者说相机拍摄的视频，因为有噪音的存在。而且视频中不规则的运动，扭曲形变，遮挡，亮度等的变化，很难被完全预测。所以混合编码框架会将当前块的原始图像减去预测图像得到残差图像，或者说当前块减去预测块得到残差块。残差块通常要比原始图像简单很多，因而预测可以显著提升压缩效率。对残差块也不是直接进行编码，而是通常先进行变换。变换是把残差图像从空间域变换到频率域，去除残差图像的相关性。残差图像变换到频率域以后，由于能量大多集中在低频区域，变换后的非零系数大多集中在左上角。接下来利用量化 来进一步压缩。而且由于人眼对高频不敏感，高频区域可以使用更大的量化步长。
国际视频编码标准制定组织JVET已成立超越H.266/VVC编码模型研究的小组，并将该模型，即平台测试软件，命名为增强的压缩模型(Enhanced Compression Model，简称ECM)。ECM在VTM10.0的基础上开始接收更新和更高效的压缩算法，目前已超越VVC约13％的编码性能。ECM不仅扩大了特定分辨率的编码单元尺寸，同时也集成了许多帧内预测和帧间预测技术，本申请主要涉及帧内预测技术。
ECM是进一步提高VVC性能的工具以及工具间的组合的参考软件，它基于VTM-10.0，集成EE采纳的工具和技术。
在ECM的帧内编码中，与VTM(VVC的参考软件测试平台)类似的，有传统的帧内预测，残差的变换等过程。与VVC不同的是在帧内预测环节中，采纳了两项用于导出帧内预测模式的技术，分别是解码器端帧内模式导出(Decoder-side Intra Mode Derivation，DIMD)和基于模板的帧内模式导出(Template-based Intra Mode Derivation，TIMD)。
TIMD和DIMD技术可在解码端导出帧内预测模式，从而省去编码帧内预测模式的索引，以达到节省码字的作用。
TIMD利用编解码端同样操作导出预测模式的方式来节省传输模式索引开销，同时使用融合的方法提高帧内预测的预测块质量。ECM2.0中的TIMD技术主要可以理解成两个主要部分，首先根据模板计算原始帧内预测角度模式和非角度模式的代价信息，最小代价及次小代价对应的预测模式将被选中，最小代价对应的预测模式记为模式1(记为mode1)，次小代价对应的预测模式记为模式2(记为mode2)。原始帧内预测角度模式在现有ECM中设计为从MPM列表中获取，已达到减少复杂度的效果。原始帧内预测角度共有65个角度模式和2个非角度模式，全遍历67种预测模式无论是在编码端还是解码端都是相当大的代价和负担，而遍历MPM列表中的预测模式是一种权衡性能与复杂度的优化方案。
如图7所示，TIMD通过当前块上方、左侧、左上、左下和右上五个块选中的帧内预测模式，导出最可能模式(Most Probable Mode，简称MPM)列表。如图7所示，以参考模板(reference of the template)中的重建值作为参考行，分别对模板(template)区域做出预测结果。分别计算template的重建值与每种模式预测结果之间的绝对变换差之和(Sum of absolute transformed differences，简称SATD)，SATD最小和次小的两种模式将作为当前块的预测模式进行预测并加权。
若MPM列表中存在至少两个预测模式，且不包括任何角度预测模式，则TIMD不进行融合操作，仅使用mode1得到的预测块作为当前编码单元的预测块。
否则，TIMD融合技术会进一步细化预测模式，若mode1为角度模式，则以mode1作为中心预测方向，向左和右分别偏移一定角度，得到mode1 +和mode1 -，若mode1 +和mode -的代价信息比mode1更小，则替换mode1作为更新后的最优预测模式；同理，对mode2进行细化。
若次小代价数值costMode2与最小代价数值costMode1比例满足加权融合条件，如costMode2<2*costMode1，则将mode1与mode2各对应的预测块按预设权重加权融合，预设权重根据代价信息计算得到。
例如，根据如下公式(1)和(2)确定出mode1和model2对应的权重：
weight1＝costMode2/(costMode1+costMode2)  (1)
weight2＝1-weight1   (2)
根据上述公式步骤确定出mode1和model2对应的权重后，根据如下公式(3)，确定出当前块的预测值：
Pred＝Pred mode1×w1+Pred mode2×w2   (3)
其中，weight1即为mode1对应预测值的加权权重，weight2即为mode2对应预测值的加权权重，Pred mode1为mode1对应预测块，Pred mode2为mode2对应预测值，Pred为TIMD的预测值。
若次小代价数值costMode2与最小代价数值costMode1比例不满足加权融合条件，则不做预测值之间的加权融合，则将mode1对应预测值即为TIMD的预测值。
若当前块的上方、左侧、左上、左下和右上这五个参考重建样本均不可用，则TIMD技术选择planar模式进行预测，且不加权融合。
在一些实施例中，TIMD需要传输一个标志位到解码端来表示当前编码单元是否使用TIMD技术。
由上述可知，TIMD技术的预测模式导出能够减轻一定的语法元素传输负担，使得原本需要至少5个比特或更多的预测模式开销节省到1个比特。而且TIMD在获得预测模式信息后通过融合操作，将最优预测模式和次优预测模式的预测值进行融合，产生新的预测值。该新的预测值既不是前述任一种预测模式所能够预测得到的，也不存在后续预测工具中能够得到一样的预测值。通过实验对比，可以发现该融合技术确实提升了预测效率。
但是，通过加权融合得到的预测值适用于自然场景的视频内容，却不适用于特定场景下的视频内容。前者视频内容中的物体通常都有较为模糊的边缘以及拍摄所产生的一些噪声，TIMD的融合技术能够得到更匹配于这些物体的预测值。而后者视频内容中的物体一般都有较为锐化和颜色鲜明的特性，这些视频内容通常为电脑录制或称为屏幕内容视频，TIMD的融合技术所产生的预测值在此类内容中显得多余并降低了预测质量，可以说是带来了噪声。
因此，在一些图像内容中，使用TIMD的融合技术不仅没能提升压缩效率，反而降低预测质量，引入了不必要的噪声。
为了解决上述技术问题，本申请根据当前序列的图像内容来确定加权融合条件，也就是说，不同的图像内容对应的加权融合条件可以不同，这样根据当前序列的图像内容对应的加权融合条件，来判断是否对当前块进行加权融合预测，可以避免对不需要加权融合预测的图像内容进行加权融合预测时，降低预测质量，引入不必要噪声的问题，进而提高了帧内预测的准确性。
需要说明的是，本申请实施例提供的帧内预测方法，除了可以应用于上述TIMD技术中外，还可以应用于任意允许采用两种或多种帧内预测模式进行加权融合预测的场景中。
下面结合具体的实施例，对本申请实施例提供的视频编解码方法进行介绍。
首先结合图8，以解码端为例，对本申请实施例提供的视频解码方法进行介绍。
图8为本申请实施例提供的帧内预测方法的一种流程示意图。本申请实施例应用于图1和图2所示视频解码器。如图8所示，本申请实施例的方法包括：
S401、解码码流，确定当前块的第一帧内预测模式和第二帧内预测模式。
在一些实施例中，当前块也可以称为当前解码块、当前解码单元、解码块、待解码块、待解码的当前块等。
在一些实施例中，当前块包括色度分量不包括亮度分量时，当前块可以称为色度块。
在一些实施例中，当前块包括亮度分量不包括色度分量时，当前块可以称为亮度块。
需要说明的是，视频解码器确定当前块允许采用两种帧内预测模式进行融合加权预测时，则视频解码器确定第一帧内预测模式和第二帧内预测模式。在判断该第一帧内预测模式和第二帧内预测模式符合加权融合条件时，则使用第一帧内预测模式对当前块进行预测，得到当前块的第一个预测值，使用第二帧内预测模式对当前块进行预测，得到当前块的第二个预测值，将第一个预测值和第二个预测值进行加权融合，得到当前块的目标预测值。
在一些实施例中，若判断第一帧内预测模式和第二帧内预测模式不满足加权融合条件时，则使用第一帧内预测模式和第二帧内预测模式中的一个帧内预测模式，对当前块进行预测，得到当前块的目标预测值。
在一些实施例中，视频解码器确定当前块允许采用两种帧内预测模式进行融合加权预测的方式可以是：视频编码器在码流中携带第二标志，该第二标志用于指示当前块是否通过第一帧内预测模式和第二帧内预测模式中的至少一个确定目标预测值。若视频编码器使用第一帧内预测模式和第二帧内预测模式中的至少一个确定目标预测值，则将第二标志置为真，例如将第二标志的取值置为1，并将置为真的第二标志写入码流中，例如写入码流头中。这样视频解码器获得码流后，解码该码流，得到第二标志，若该第二标志为真，例如该第二标志的取值为1，则视频解码器确定当前块是通过第一帧内预测模式和第二帧内预测模式中的至少一个确定目标预测值，此时，视频解码器确定当前块的第一帧内预测模式和第二帧内预测模式。可选的，视频解码器确定第一帧内预测模式和第二帧内预测模式的方式与视频编码器确定第一帧内预测模式和第二帧内预测模式的方式相同。
若视频编码器不是通过第一帧内预测模式和第二帧内预测模式中的至少一个确定当前块的目标预测值时，则将第二标志置为假，例如将第二标志的取值置为0，并将置为假的第二标志写入码流中，例如写入码流头中。视频解码器解码码流，得到第二标志，若该第二标志为假，例如该第二标志的取值为0，则视频解码器不确定当前块的第一帧内预测模式和第二帧内预测模式，而是遍历预设的帧内预测模式，确定出代价最小的帧内预测模式对当前块进行预测，得到当前块的目标预测值。
需要说明的是，本申请实施例主要涉及到当前块的目标预测值是通过第一帧内预测模式和第二帧内预测模式中的至少一个确定的，也就是说，本申请主要讨论上述第二标志为真的情况。
在一种可能的实现方式中，若本申请采用TIMD技术，则上述第二标志可以为TIMD使能标志，例如为sps_timd_enable_flag。也就是说，在本申请实施例中，视频解码器解码码流，得到TIMD的允许使用标志位，该TIMD的允许使用标志位为序列级标志位。该TIMD的允许使用标志位用于指示当前序列是否允许使用TIMD技术。若TIMD的允许使用标志位为真时，例如为1时，则确定该当前序列允许使用TIMD技术。接着，视频解码器继续解码码流，得到TIMD使能标志，该TIMD使能标志可以为序列级标志。该TIMD使能标志用于指示当前块是否使用TIMD技术，若该TIMD使能标志为真，例如为1，则确定当前块使用TIMD技术，此时视频解码器确定当前块的第一帧内预测模式和第二帧内预测模式。
可选的，上述TIMD使能标志还可以是图像级序列，用于指示当前帧图像是否使用TIMD技术。
需要说明的是，TIMD使能标志的真假是由视频编码器确定的并写入码流中，例如，视频编码器采用TIMD技术确定当前块的目标预测值时，则将TIMD使能标志置为真，例如置为1，且写入码流，例如写入码流头。若视频编码器未采用TIMD技术确定当前块的目标预测值时，则将TIMD使能标志置为假，例如置为0，且写入码流，例如写入码流头中。这样视频解码器可以从码流中解析出TIMD使能标志，并根据TIMD使能标志来确定是否使用TIMD技术来确定当前块的目标预测值，进而保证解码端和编码端的一致，保证预测的可靠性。
视频解码器确定出需要通过第一帧内预测模式和第二帧内预测模式中的至少一个来确定当前块的目标预测值时，执行上述S401确定当前块的第一帧内预测模式和第二帧内预测模式。
本申请中，上述S401中确定当前块的第一帧内预测模式和第二帧内预测模式的方式包括但不限于如下几种：
方式一，遍历预设的帧内预测列表，从中选出代价最小的帧内预测模式作为第一帧内预测模式，选出次小的帧内预测模式作为第二帧内预测模式。
上述预设的帧内预测列表可以包括直流(Direct Current，DC)模式、平面(PLANAR)模式以及角度模式任意一种帧内编码模式等。
在该方式一中，视频解码器，遍历预设的帧内预测列表中的不同帧内预测模式分别对当前块进行预测编码，然后计算多种预测模式下每一种预测模式对应的代价。将最小代价对应的帧内预测模式确定为当前块的第一帧内预测模式，将次小代价对应的帧内预测模式，确定为当前块的第二帧内预测模式。
可选的，上述各预测模式对应的代价可以为SAD或SATD等作为各预测模式的近似代价。可选的，可以使用当前块和当前块的预测值来确定SAD和SATD。例如，使用某一个帧内预测模式对当前块进行预测，得到当前块的预测值，将当前块与当前块的预测值的像素差值，确定为该帧内预测模式对应的SAD。将当前块与当前块的预测值进行相减，得到当前块的残差值，对残差值进行Hadamard变换后再求各元素绝对值之和，进而得到该帧内预测模式对应的SATD。
假设预设的帧内预测列表中包括的帧内预测模式有66种，第一帧内预测模式有66种可能，由于第二帧内预测模式与第一帧内预测模式不相同，因此第二帧内预测模式有65种，那么本申请可能使用任意两种不同的帧内预测模式， 共有66×65种可能。可见，在本申请中，遍历帧内预测列表中的各帧内预测模式，耗时，效率低，因此，本申请可以限制可以选择的帧内预测模式。
方式二，根据当前块的MPM确定当前块的第一帧内预测模式和第二帧内预测模式。即上述S401包括如下S401-A1和S401-A2的步骤：
S401-A1、确定当前块的最有可能模式：
S401-A2、根据最有可能模式，确定第一帧内预测模式和第二帧内预测模式。
在帧内预测中可以使用最可能模式列表(MostprobableModes List，MPM)的帧内模式编码技术来提高编解码效率。利用周边已编解码的块的帧内预测模式，以及根据周边已编解码块的帧内预测模式导出的帧内预测模式，如相邻的模式，以及一些常用或使用概率比较高的帧内预测模式，如DC，Planar，Bilinear模式等，构成一个模式列表。参考周边已编解码的块的帧内预测模式利用了空间上的相关性。因为纹理在空间上会有一定的连续性，MPM可以作为帧内预测模式进行预测。也就是认为当前块使用MPM的概率会比不使用MPM的概率高。因而在二值化时，会给MPM使用更少的码字，从而节省开销，以提高编解码效率。
由上述可知，MPM根据当前块周围已解码区域的帧内预测模式组成，这样视频解码器获得当前块周围已解码的区域区域中的图像块所使用的帧内预测模式，进而组成当前块的MPM。例如，使用当前块上方、左上、右上等区域的帧内预测模式，构成当前块的MPM。
在一些实施例中，若本申请采用TIMD技术时，则如图7所示，将当前块的右上区域、上方区域、左上区域、左侧区域和左下区域中已解码区域的帧内预测模式，构成当前块的MPM。例如，右上区域在解码时使用的帧内预测模式1，上方区域在解码时使用的帧内预测模式2，左上区域在解码时使用的帧内预测模式3，左侧区域在解码时使用的帧内预测模式2，左下区域在解码时使用的帧内预测模式4，这样，可以确定当前块的MPM中包括帧内预测模式1、帧内预测模式2、帧内预测模式3和帧内预测模式4。
需要说明的是，若当前块的右上区域、上方区域、左上区域、左侧区域和左下区域中有部分区域未解码时，则使用这些区域中已解码区域对应的帧内预测模式构建当前块的MPM。
可选的，若当前块第一个待解码块，也就是说当前块周围不存在已解码的区域，此时，可以预设的多个帧内预测模式中选出几个帧内预测模式构建当前块的MPM。
可选的，若当前块为第一待解码块时，则采用上述方式一的方法，遍历预设的帧内预测列表中的每个帧内预测模式，得到代价最小的第一帧内预测模式和代价次小的第二帧内预测模式。
根据上述方法确定出当前块的MPM后，根据该MPM，确定第一帧内预测模式和第二帧内预测模式。为了便于描述，将MPM中的帧内预测模式记为候选帧内预测模式。其中，根据该MPM，确定第一帧内预测模式和第二帧内预测模式的方式包括但不限于如下几种示例：
示例1，将上述MPM中的一个候选帧内预测模式，确定为第一帧内预测模式，将该MPM中除第一帧内预测模式外的一个候选帧内预测模式，确定为第二帧内预测模式。例如，将MPM中的任意一个候选帧内预测模式确定为第一帧内预测模式，将该MPM中除第一帧内预测模式外的任意一个候选预设模式确定为第二帧内预测模式。
示例2，确定使用该MPM中的候选帧内预测模式，对当前块进行预测时的代价；根据该MPM中候选帧内预测模式对应的代价，确定第一帧内预测模式和第二帧内预测模式。例如，使用MPM中的每个候选帧内预测模式对当前块进行预测编码，得到每个候选帧内预测模式对应的代价。接着，根据MPM中每个候选帧内预测模式对应的代价，确定第一帧内预测模式和第二帧内预测模式，例如，将MPM中代价最小的候选帧内预测模式确定为第一帧内预测模式，将MPM中代价次小的候选帧内预测模式确定为第二帧内预测模式。
可选的，上述代价可以为SAD或SATD等，本申请对此不做限制。
该方式二中，通过确定当前块的MPM，并根据MPM中各候选帧内预测模式对当前块进行预测编码时的代价，确定当前块的第一帧内预测模式和第二帧内预测模式，由于MPM中所包括的帧内预测模式较少，进而降低了第一帧内预测模式和第二帧内预测模式的确定复杂度，提高了第一帧内预测模式和第二帧内预测模式的确定速度，进而提升预测效率。
若本申请采用TIMD技术时，则采用如下方式三，确定当前块的第一帧内预测模式和第二帧内预测模式。
方式三，基于TIMD技术确定当前块的第一帧内预测模式和第二帧内预测模式。即上述S401包括如下S401-B1和S401-B2的步骤：
S401-B1、解码码流，得到TIMD使能标志，该TIMD使能标志用于指示当前块是否采用TIMD技术；
S401-B2、若TIMD使能标志指示当前块使用TIMD技术时，则确定当前块的第一帧内预测模式和第二帧内预测模式。
由上述可知，TIMD技术是基于模板来导出帧内预测模式，基于此，视频解码器得到码流后，解码码流，得到TIMD使能标志，若该TIMD使能标志为真，例如该TIMD使能标志的取值为1，则确定当前块采用TIMD技术确定当前块的目标预测值。此时，可以通过对图7所示的当前块的模板进行预测编码，确定出当前块的第一帧内预测模式和第二帧内预测模式，而不是对当前块直接进行预测编码来确定第一帧内预测模式和第二帧内预测模式。由于当前块的模板为已重建区域，可以根据模板的预测值和重建值之间的差异，确定出帧内预测模式的效果，进而可以准确、快速地确定出当前块的第一帧内预测模式和第二帧内预测模式。
其中，上述S401-B2中确定当前块的第一帧内预测模式和第二帧内预测模式的方式包括但不限于如下几种示例：
示例1，遍历预设的帧内预测模式列表，使用帧内预测模式列表中的每个帧内预测模式分别对当前块的模板进行预测编码，得到每个预测模式对应的预测值。接着，将每个预测模式对应的预测值与模板的重建值进行比较，例如，计算预测模式对应的预测值与模板的重建值之间的代价，例如SAD或SATD，将代价最小的预测模式确定为当前块的第一帧内预测模式，将代价次小的预测模式确定为当前块的第二帧内预测模式。
示例2，通过如下S401-B21和S401-B22的步骤确定出当前块的第一帧内预测模式和第二帧内预测模式。
S401-B21、若TIMD使能标志指示当前块使用TIMD技术，且当前块的多个参考重建样本中至少一个参考重建样本存在时，则确定当前块的MPM：
S401-B22、根据MPM，确定当前块的第一帧内预测模式和第二帧内预测模式。
在该示例二中，当前块的多个参考重建样本可以理解为当前块周围已重建区域，该示例2根据当前块周围多个残差重建样本的帧内预测模式，来确定当前块的MPM。当前块的多个参考重建样本为预先设定好的，例如，将当前块的上方重建区域确定为当前块的一个重建样本，将当前块的左侧重建区域确定为当前块的一个重建样本等。
在一些实施例中，如图7所示，将当前块的右上区域、上方区域、左上区域、左侧区域和左下区域记为当前块的参考重建样本。这些参考重建样本中有些存在，也称为有效，有些可能不存在，即无效，例如，当前块的左侧区域已重建，但是当前块的上方区域未重建，这样可以称为当前块的左侧区域的参考重建样本存在(即有效)，当前块的上方区域的参考重建样本不存在(即无效)。
在该示例2中，若TIMD使能标志指示当前块使用TIMD技术，且当前块的多个参考重建样本中至少一个参考重建样本存在时，则根据存在的参考重建样本对应的帧内预测模式，构建当前块的MPM，例如，当前块存在的参考重建样本为K个，在帧内预测时分别使用的帧内预测模式为帧内预测模式1、帧内预测模式2…..，帧内预测模式K，则使用帧内预测模式1、帧内预测模式2…..，以及帧内预测模式K构建当前块的MPM。可选的，上述K为小于5的正整数。
根据上述步骤，确定出当前块的MPM后，则根据该MPM，确定当前块的第一帧内预测模式和第二帧内预测模式。
例如，若MPM中的帧内预测模式个数大小大于1，则将MPM中的任意一个帧内预测模式确定为当前块第一帧内预测模式，将MPM中除第一帧内预测模式外的其他任意一个帧内预测模式，确定为当前块的第二帧内预测模式。
在一些实施例中，若MPM中的帧内预测模式的个数等于1，则将MPM中的帧内预测模式确定为第一帧内预测模式，从其他的帧内预测模式中确定出一个，作为当前块的第二帧内预测模式。例如，将其他帧内预测模式中代价最小的帧内预测模式确定为第二帧内预测模式。
在一些实施例中，若MPM中的帧内预测模式的个数等于1，则将MPM中的帧内预测模式确定为第一帧内预测模式，将Planar模式确定为第二帧内预测模式。
在一些实施例中，若MPM中的帧内预测模式的个数等于1，则确定不对当前块进行加权融合预测，使用MPM中的帧内预测模式对当前块进行预测，得到当前块的目标预测值。
在一些实施例中，若MPM中的候选帧内预测模式的个数大于1时，则确定使用MPM中的候选帧内预测模式，对当前块的模板区域进行预测时的代价，根据MPM中候选帧内预测模式对应的代价，确定第一帧内预测模式和第二帧内预测模式。例如，将MPM中代价最小的候选帧内预测模式确定为第一帧内预测模式，将MPM中代价次小的候选帧内预测模式确定为第二帧内预测模式。
可选的，上述代价可以为SAD或SATD等代价。
在一种示例中，上述确定使用MPM中的候选帧内预测模式，对当前块的模板区域进行预测时的代价的过程可以是：确定使用MPM中的候选帧内预测模式，对当前块的模板区域进行预测时的预测值；根据候选帧内预测模式对应的预测值和模板区域的重建值，确定候选帧内预测模式对应的代价。具体是，针对MPM中的一个候选帧内预测模式，得到使用该候选帧内预测模式对当前块的模板区域进行预测时的预测值，由于模板区域为已重建区域，重建值已知。接着，根据该帧内预测模式对应的预测值和模板区域的重建值，确定该候选帧内预测模式对应的代价。例如，将将该帧内预测模式对应的预测值和模板区域的重建值之间的SAD或SATD确定为该候选帧内预测模式的代价。
在一些实施例中，若TIMD使能标志指示当前块采用TIMD技术，且当前块的多个参考重建样本均不存在时，视频解码器不确定当前块的第一种帧内预测模式和第二帧内预测模式，而是使用Planar模式对当前块进行预测，得到当前块的目标预测值。
根据上述方式一至方式三中的任意一个，可以确定出当前块的第一帧内预测模式和第二帧内预测模式。
在一些实施例中，上述方式二至方式三中，根据所述最有可能模式列表中候选帧内预测模式对应的代价，确定所述第一帧内预测模式和第二帧内预测模式，包括如下几种方式：
方式1，将最有可能模式列表中代价最小的候选帧内预测模式，确定为第一帧内预测模式，将所述最有可能模式列表中代价次小的候选帧内预测模式，确定为第二帧内预测模式。
方式2，将最有可能模式列表中代价最小的候选帧内预测模式，确定为第一初始模式，将最有可能模式列表中代价次小的候选帧内预测模式，确定为第二初始模式；若第一初始模式和第二初始模式中的至少一个为角度预测模式时，则根据预设的偏移量，对第一初始模式和第二初始模式中的角度预测模式进行偏移处理，得到第一帧内预测模式和第二帧内预测模式。
在一些实施例中，若第一初始模式为角度预测模式时，则以第一初始模式作为中心预测方向，向左和右分别偏移一定角度，得到mode1 +和mode1 -，确定使用mode1 +和mode1 -分别对当前块的模板区域进行预测时的代价，将mode1 +、mode1 -和第一初始模式中代价最小的预测模式，确定为第一帧内预测模式。
在一些实施例中，若第二初始模式为角度预测模式时，则以第二初始模式作为中心预测方向，向左和右分别偏移一定角度，得到mode2 +和mode2 -，确定使用mode2 +和mode2 -分别对当前块的模板区域进行预测时的代价，将mode2 +、mode2 -和第二初始模式中代价最小的预测模式，确定为第二帧内预测模式。
在一些实施例中，若第一初始模式和第二初始模式均不为角度预测模式时，则将第一初始模式确定为第一帧内预测模式，将第二初始模式，确定为第二帧内预测模式。
根据上述方法，确定出当前块的第一帧内预测模式和第二帧内预测模式后，执行如下S402和S403的步骤。
S402、根据当前序列的图像内容，确定当前块的加权融合条件。
上述加权融合条件用于判断当前块是否通过第一帧内预测模式和第二帧内预测模式进行加权预测。
S403、根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的目标预测值。
在本申请实施例中，视频解码器根据上述S401的步骤得到当前块的第一帧内预测模式和第二帧内预测模式后，并不是直接使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测，而是需要判断第一帧内预测模式和第二帧内预测模式是否满足当前块的加权融合条件。若第一帧内预测模式和第二帧内预测模式满足当前块的加权融合条件时，则使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测，例如使用第一帧内预测模式对当前块进行预测，得到第一个预测值，使用第二帧内预测模式对当前块进行预测，得到第二个预测值，对第一个预测值和第二个预测值进行加权，得到当前块的目标预测值。其中，第一个预测值和第二个预测值进行加权时的权重，可以根据第一帧内预测模式和第二帧内预测模式的代价确定，例如，第一帧内预测模式对当前块进行预测时的代价记为第一代价cost1，第二帧内预测模式对当前块进行预测时的代价记为第二代价cost2，上述第一代价和第二代价可以是SAD或SATD等代价。weight1为第一个预测值对应的权重，weigh2为第二个预测值对应的权重，可选的，weight1＝cost2/(cost1+cost2)，weight2＝1-weight1。这样，根据上述公式(3)将第一个预测值和第二个预测值进行加权，得到当前块的目标预测值。
若第一帧内预测模式和第二帧内预测模式不满足当前块的加权融合条件时，则使用第一帧内预测模式和第二帧内预测模式中的一个，对当前块进行预测，得到当前块的目标预测值。例如，使用第一帧内预测模式和第二帧内预测模式中代价最小的预测模式对当前块进行预测，得到当前块的目标预测值。可选的，由上述S401的部分描述可知，第一帧内预测模式为多个预测模式中代价最小的帧内预测模式，第二帧内预测模式为多个预测模式中代价次小的帧内预测模式，也就是说，第一代价小于第二代价，因此，在第一帧内预测模式和第二帧内预测模式不满足当前块的加权融合条件时，则使用第一帧内预测模式对当前块进行预测，得到当前块的目标预测值。
目前的加权融合条件是固定的，也就是说无论图像内容是什么样的，当前块的加权融合条件固定不变。但是，对于一些图像内容，例如屏幕录制的图像内容，一般都有较为锐化和颜色鲜明的特性，对这些图像内容采用加权融合预测时，由于加权融合预测可以理解为一种模糊预测方法，会降低图像中的锐化和颜色鲜明度，进而降低预测质量，带来了噪声。
为例解决上述技术，本申请根据图像内容来确定当前块的加权融合条件。也就是说，本申请针对图像内容，提供差异化的加权融合条件，不同的图像内容对应的加权融合条件可以不同，进而保证了对需要进行加权融合预测的图像内容进行加权融合预测，以提高预测准确性。对于不需要进行加权融合预测的图像内容不进行加权融合预测，以避免引入不必要的噪声，保证预测质量。
一个序列包括一系列图像，这一系列图像通过是在同一个环境中产生的，因此，一个序列中的图像的图像内容基本一致。因此，本申请通过当前序列的图像内容来确定当前块的加权融合条件，可以理解的是，当前块的图像内容与当前序列的图像内容的类型一致，例如均为屏幕内容，或者摄像头采集的其他内容等。
在一些实施例中，视频解码设备可以通过图像识别的方法，得到当前序列的图像内容。例如，视频解码设备对当前序列进行解码，首先采用已有的方式，解码出当前序列中的前几帧的重建图像，例如2帧。对前几帧的重建图像进行图像识别，得到前几帧的重建图像的图像内容的类型，将前几帧的重建图像的图像内容的类型作为当前序列的图像内容的类型。在一种示例中，视频解码设备对前几帧的重建图像进行图像识别，得到前几帧的重建图像的图像内容的类型方法可以是神经网络模型的方法。例如，该神经网络模型为预先训练好的可以识别出图像内容的类型，视频解码设备将前几帧的重建图像输入神经网络模型中，得到神经网络模型输出的前几帧的重建图像的图像内容的类型。可选的，视频解码设备还可以采用其他的方式，确定出前几帧的重建图像的图像内容的类型，本申请对此不做限制。
在一些实施例中，视频解码设备可以通过码流中的指示信息，得到当前序列的图像内容。例如，视频编码设备将当前序列的图像内容的类型通过标志位的方式写入码流，视频解码设备解码码流，得到该标志位，并通过该标志位，确定出当前序列的图像内容的类型，例如该标志位的取值为1时，指示当前序列的图像内容为第一图像内容，该标志位的取值为0时，指示当前序列的图像内容为第二图像内容，其中第一图像内容与第二图像内容不同。
根据上述方式，得到当前序列的图像内容后，根据当前序列的图像内容，确定当前块的加权融合条件，例如，当前序列的图像内容为第一图像内容时，则确定当前块的加权融合条件为第一融合条件，若当前序列的图像内容为第二图像内容时，则确定当前块的加权融合条件为第二融合条件，若当前序列的图像内容为第三图像内容时，则确定当前块的加权融合条件为第三融合条件......，若当前序列的图像内容为第N图像内容时，则确定当前块的加权融合条件为第N融合条件，具体的，如表1所示。
表1
图像内容的类型 加权融合条件的类型
第一图像内容 第一融合条件
第二图像内容 第二融合条件
…… ……
第N图像内容 第N融合条件
上述表1中表示出了不同的图像内容与不同的加权融合条件对应，上述表1为事先设定的好的。这样视频解码设备在确定出当前序列的图像内容后，在表1中进行查找，将当前序列的图像内容对应的加权融合条件，确定为当前块的加权融合条件。
在一些实施例中，上述S402中根据当前序列的图像内容，确定当前块的加权融合条件包括如下步骤：
S402-A、解码码流，得到第一标志，该第一标志用于是否使用第一技术，第一技术在第一图像内容下使用；
S402-B、根据第一标志，确定当前块的加权融合条件。
本申请的第一图像内容可以为具有锐化和鲜明颜色特征的图像内容，例如为屏幕录制内容等。
在本申请的一些实施例中，可以理解为在当前序列的图像内容为第一图像内容时，加权融合条件才可能发生变化，若当前序列的图像内容不是第一图像内容时，则加权融合条件不发生变化。也就是说，若当前序列的图像内容为第一 图像内容时，采用的加权融合条件为第一融合条件，若当前序列的图像内容非第一图像内容时，则采用的加权融合条件为第二融合条件。其中第一融合条件与第二融合条件不同。
基于此，为了提高视频解码器确定当前块的加权融合条件的效率，若视频编码器在确定当前块对应的图像内容为第一图像内容时，确定当前块可以使用第一技术，该第一技术可以理解为本申请实施例提供的技术，即根据第一帧内预测模式和第二帧内预测模式的幅度值确定当前块的加权融合条件。若视频编码器确定当前块可以使用第一技术时，则将第一标志置为真后编入码流，例如第一标志的取值为1。若视频编码器确定当前块对应的图像内容不是第一图像内容时，则确定当前块不可以使用第一技术，则将第一标志的取值置为假后编入码流，例如第一标志的取值为0。这样，视频解码器解码码流，得到该第一标志，进而根据该第一标志确定当前块的加权融合条件。
可选的，上述第一标志可以为序列级标志，用于指示当前序列是否可以使用第一技术。
可选的，上述第一标志可以为图像级标志，用于指示当前图像是否可以使用第一技术。
可选的，在码流中增加新字段来表示第一标志。例如，用字段sps_timd_blendoff_flag来表示第一标志，该字段为全新的字段。
可选的，上述第一标志复用当前序列中的第三标志，也就是说，可以复用当前序列中已有的字段，无需增加新的字段，进而节约码字。例如，上述第三字段为帧内块复制(Intra-block copy，简称IBC)使能标志或者为模板匹配预测(Template matching prediction，简称TMP)使能标志等。
在一些实施例中，可以根据第一标志，从预设的多个加权融合条件中确定出当前块的加权融合条件。例如，表2示出了第一标志所对应的加权融合条件。
表2
第一标志的取值 加权融合条件的类型
1 第一融合条件
0 第二融合条件
上述表2中示出了第一标志的不同取值所对应的加权融合条件，第一标志的取值为1，表示当前序列的图像内容为第一图像内容，对应的加权融合条件为第一融合条件。第一标志的取值为0，表示当前序列的图像内容不是第一图像内容，对应的加权融合条件为第二融合条件。基于表2，视频解码设备解码码流，得到第一标志，并根据第一标志的取值，从上述表2中，查询到当前块的加权融合条件，例如，当第一标志的取值为1时，则确定当前块的加权融合条件为第一融合条件，当第一标志的取值为0时，则确定当前块的加权融合条件为第二融合条件。
该实施例示出的根据第一标志，在上述表2中进行查询，得到当前块的加权融合条件。
在一些实施例中，则根据第一标志，确定当前块的加权融合条件，此时，上述S402-B包括如下步骤：
S402-B1、若第一标志指示使用第一技术时，则确定当前块的第一融合条件；
S402-B2、将第一融合条件确定为当前块的加权融合条件。
在该实施例中，视频解码器解码码流，得到第一标志，若该第一标志指示当前视频解码器使用第一技术，例如第一标志的取值为1时，指示当前视频解码器可以使用第一技术时，视频解码器确定当前块的加权融合条件需要进行修改，无法使用已有的加权融合条件，此时，视频解码器重新为当前块确定加权融合条件。具体是，视频解码器确定当前块的第一融合条件，并将该第一融合条件确定为当前块的加权融合条件。
上述S402-B1中确定当前块的第一融合条件的方法包括但不限于如下几种：
第一种方式：将第一阈值系数的取值修改为第一预设值，根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及修改后的第一阈值系数，确定第一融合条件。
上述第一阈值系数用于确定第一融合条件。
在一些实施例中，上述第一阈值系数具有默认值，例如为2或其他数值，本申请实施例中，若当前序列的图像内容为第一图像内容(例如屏幕录制内容)时，则对该第一阈值系数进行修改，例如从默认值修改为第一预设值，进而根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及修改后的第一阈值系数，确定第一融合条件。
可选的，上述第一预设值小于第一阈值系数的默认值。
可选的，上述第一预设值为小于2的正数，例如为1.9或1.95等。
该方式一中，对根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及修改后的第一阈值系数，确定第一融合条件的方式不做限制。
在一种示例中，将第二代价与第一代价的比值小于修改后的第一阈值系数作为当前块的第一融合条件。例如，当前块的第一融合条件为：cost2/cost1<a1，其中cost1为第一帧内预测模式对应的第一代价，cost2为第二帧内预测模式对应的第二代价，a1为修改后的第一阈值系数。
本申请实施例中，假设第一阈值系数未修改之前的取值为a，修改后的取值为a1，且a大于a1。假设已有的加权融合条件为：cost2/cost1<a，而本申请修改后的加权融合条件为：cost2/cost1<a1，由于a1小于a，且cost1小于cost2，因此，本申请修改后的加权融合条件更加严格，例如cost2满足未修改之前的加权融合条件时，cost2的取值范围为：cost1<cost2<acost1，cost2满足修改之前的加权融合条件时，cost2的取值范围为：cost1<cost2<a1cost1。由于a1小于a，因此，cost2要满足修改后的加权融合条件时，其取值范围变小，进而使得第一帧内预测模式和第二帧内预测模式不容易满足本申请修改后的加权融合条件，这样，使用修改后的加权融合条件进行加权预测判断时，可以降低对第一图像内容的当前块进行加权预测的概率，从而保证了第一图像内容的当前块的预测质量。
在另一种示例中，将第二代价小于第一代价与修改后的第一阈值系数的乘积作为当前块的第一融合条件。例如，当前块的第一融合条件为：cost2<a1 cost1。
在该示例中，假设第一阈值系数未修改之前的取值为a，修改后的取值为a1，且a大于a1。假设已有的加权融合 条件为：cost2<a cost1，而本申请修改后的加权融合条件为：cost2<a1 cost1，由于a1小于a，且cost1小于cost2，因此，本申请修改后的加权融合条件更加严格，例如cost2满足未修改之前的加权融合条件时，cost2的取值范围为：cost1<cost2<acost1，cost2满足修改之前的加权融合条件时，cost2的取值范围为：cost1<cost2<a1cost1。由于a1小于a，因此，cost2要满足修改后的加权融合条件时，其取值范围变小，进而使得第一帧内预测模式和第二帧内预测模式不容易满足本申请修改后的加权融合条件，这样，使用修改后的加权融合条件进行加权预测判断时，可以降低对第一图像内容的当前块进行加权预测的概率，从而保证了第一图像内容的当前块的预测质量。
在该第一种方式中，假设当前块的第一融合条件为cost2<a1 cost1，此时，上述S403中根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的目标预测值包括如下步骤S403-A1：
S403-A1、若第二代价小于第一代价与修改后的第一阈值系数的乘积，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的目标预测值。
也就是说，当cost2<a1 cost1时，说明第一帧内预测模式和第二帧内预测模式满足当前块的加权融合条件，因此，使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测，得到当前块的目标预测值。例如，使用第一帧内预测模式对当前块进行预测，得到第一个预测值，使用第二帧内预测模式对当前块进行预测，得到第二个预测值，对第一个预测值和第二个预测值进行加权，得到当前块的目标预测值，例如根据上述公式(1)至公式(3)所示的加权方法，加权运算得到当前块的目标预测值。
需要说明的是，第一个预测值和第二个预测值进行加权运算的权重除了根据上述公式(1)和公式(2)的计算方法外，还可以采用权重矩阵的方式导出，例如，几何划分预测模式(GeometricpartitioningMode，GPM)存在有64种权重划分模式，角度加权预测模式(Angular Weightedprediction，AWP)存在有56种权重划分模式，本申请可以从GPM的64种权重划分模式中或者AWP存在有56种权重划分模式中选择一种权重划分模式对应的权重分布，作为第一帧内预测模式对应的第一个预测值和第二帧内预测模式对应的第二个预测值的权重。例如，第一帧内预测模式为角度预测模式，则将与第一帧内预测模式的角度重合或近似重合的权重划分模式对应的权重分布，确定为第一个预测值和第二个预测值对应的权重。
在一些实施例中，上述S403还包括如下S403-A2：
S403-A2、若第二代价大于或等于第一代价与修改后的第一阈值系数的乘积，则使用第一帧内预测模式，确定当前块的目标预测值。
本申请实施例中，当第一帧内预测模式和第二帧内预测模式不满足上述确定的当前块的加权融合条件，即不满足cost2<a1 cost1，也就是说，第二帧内预测模式对应的第二代价大于或等于第一帧内预测模式对应的第一代价与修改后的第一阈值系数的乘积时，视频解码器对当前块不进行加权预测，而是使用第一帧内预测模式和第二帧内预测模式中代价最小的一个帧内预测模式进行预测。由上述可知，第一代价小于第二代价，因此视频解码器直接使用第一帧内预测模式对当前块进行预测，将预测得到的预测值，确定为当前块的目标预测值。
在该第一种方式中，视频解码器解码码流，得到第一标志，若第一标志指示使用第一技术时，则视频解码器将第一阈值系数的取值修改为第一预设值，并根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及修改后的第一阈值系数，确定第一融合条件，例如将第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积作为第一融合条件，进而将当前块的第一融合条件作为当前块的加权融合条件。该第一种方式中，由于对第一阈值系数改小，使得当前块的加权融合条件更加严格，进而降低了第一帧内预测模式和第二帧内预测模式满足本申请修改后的加权融合条件的概率，可以降低对第一图像内容的当前块进行加权预测的概率，从而保证了第一图像内容的当前块的预测质量。
在一些实施例中，视频解码器还可以通过如下第二种方式来确定当前块的第一融合条件。
第二种方式：根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，确定当前块的第一融合条件。
在该第二种方式中，直接根据第一代价和第二代价，来确定当前块的第一融合条件，简化了确定当前块的第一融合条件的过程，提升了基于该第一融合条件判断是否对当前块进行加权预测的速率，进而提升了解码效率。
本申请对根据第一代价和第二代价确定当前块的第一融合条件的方式不做限制。
在一种示例中，将第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价均大于某一个预设值，作为当前块的第一融合条件。例如，第一融合条件为：cost1&cost2>b。也是就是，本申请实施例中，当前第一代价和第二代价均大于某一个预设值时，说明第一帧内预测模式和第二帧内预测模式的预测效果均不佳，此时，为了提高当前块的预测效果，则可以通过第一帧内预测模式和第二帧内预测模式进行加权预测，即将第一帧内预测模式和第二帧内预测模式分别预测得到的预测值进行加权，作为当前块的目标预测值，以提高当前块的预测效果。
在一种示例中，将第一代价和第二代价中的至少一个大于或等于第一预设阈值，作为当前块的第一融合条件。例如，当前块的第一融合条件为：第一代价和第二代价中的至少一个大于或等于第一预设阈值。本申请对第一预设阈值的具体取值不做限制，具体根据实际需求确定。在该示例中，若第一帧内预测模式对应的第一代价和/或第二帧内预测模式对应的第二代价大于或等于第一预设值，说明第一帧内预测模式和/或第二帧内预测模式的预测效率不佳，此时，为了提高当前块的预测效果，则可以通过第一帧内预测模式和第二帧内预测模式进行加权预测，即将第一帧内预测模式和第二帧内预测模式分别预测得到的预测值进行加权，作为当前块的目标预测值，以提高当前块的预测效果。
在该第二种方式中，假设当前块的第一融合条件为第一代价和第二代价中的至少一个大于或等于第一预设阈值，此时，上述S403中根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的目标预测值包括如下步骤S403-B1：
S403-B1、若第一代价和第二代价中的至少一个大于或等于第一预设阈值时，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的目标预测值。
也就是说，当第一代价和第二代价中的至少一个大于或等于第一预设阈值时，说明当前块的第一帧内预测模式和/或第二帧内预测模式的预测效果不佳，此时，如果使用其中代价最小的一个预测模式进行单独预测时，由于无法保证该最小代价的预测模式的预测效率，可能造成预测不准确的问题。为了提高当前块的预测效果，视频解码器在确定第一代价和第二代价中的至少一个大于或等于第一预设阈值时，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的目标预测值。例如，使用第一帧内预测模式对当前块进行预测，得到第一个预测值，使用第二帧内预测模式对当前块进行预测，得到第二个预测值，对第一个预测值和第二个预测值进行加权，得到当前块的目标预测值，例如根据上述公式(1)至公式(3)所示的加权方法，加权运算得到当前块的目标预测值。或者，采用权重矩阵的方式导出第一个预测值和第二个预测值的权重，再根据公式(3)进行加权，得到当前块的目标预测值。例如，视频解码器从GPM的64种权重划分模式中或者AWP存在有56种权重划分模式中选择一种权重划分模式对应的权重分布，作为第一帧内预测模式对应的第一个预测值和第二帧内预测模式对应的第二个预测值的权重。例如，第一帧内预测模式为角度预测模式，则将与第一帧内预测模式的角度重合或近似重合的权重划分模式对应的权重分布，确定为第一个预测值和第二个预测值对应的权重。
在一些实施例中，上述S403还包括如下S403-B2：
S403-B2、若第一代价和第二代价均小于第一预设阈值时，则使用第一帧内预测模式，确定当前块的目标预测值。
本申请实施例中，当第一帧内预测模式和第二帧内预测模式不满足上述确定的当前块的加权融合条件，即第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价均小于第一预设值时，说明当前块的第一帧内预测模式和第二帧内预测模式的预测效果较佳。此时，使用一个帧内预测模式对当前块进行预测时，可以达到较佳的预测效果。使用加权预测方式，即使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测时，反而会降低当前块的预测效果，例如降低当前块的锐度和颜色鲜明度等。因此，在该情况下，为了保证当前块的预测质量，当第一代价和第二代价均小于第一预设阈值时，视频解码器使用第一帧内预测模式和第二帧内预测模式中代价最小的一个帧内预测模式进行预测。由上述可知，第一代价小于第二代价，因此视频解码器直接使用第一帧内预测模式对当前块进行预测，将预测得到的预测值，确定为当前块的目标预测值。
在该第二种方式中，视频解码器解码码流，得到第一标志，若第一标志指示使用第一技术时，则视频解码器根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价确定第一融合条件，例如第一代价和第二代价中的至少一个大于或等于第一预设阈值作为第一融合条件，进而将当前块的第一融合条件作为当前块的加权融合条件。该第二种方式中，若第一代价和第二代价中的至少一个大于或等于第一预设阈值时，说明当前块的第一帧内预测模式和/或第二帧内预测模式的预测效果不佳，为了提高当前块的预测效果，则视频解码器使用第一帧内预测模式和第二帧内预测模式，确定当前块的目标预测值。若第一代价和第二代价均小于第一预设阈值时，说明当前块的第一帧内预测模式和第二帧内预测模式的预测效果较佳，此时为了保证当前块的预测效果以及降低预测复杂度，则使用第一帧内预测模式，确定当前块的目标预测值。
需要说明的是，上述第二种方式，除了作为图像内容为第一图像内容的当前块的加权融合条件外，还可以作为其他的图像块的加权融合条件。也就是说，可以将上述方式二，作为第一种新的加权融合条件，判断图像块是否需要进行加权融合预测。
在一些实施例中，视频解码器还可以通过如下第三种方式来确定当前块的第一融合条件。
第三种方式：根据第一帧内预测模式和第二帧内预测模式，确定第一融合条件。
在该第三种方式中，直接根据第一帧内预测模式和第二帧内预测模式，来确定当前块的第一融合条件，简化了确定当前块的第一融合条件的过程，提升了基于该第一融合条件判断是否对当前块进行加权预测的速率，进而提升了解码效率。
本申请对根据第一帧内预测模式和第二帧内预测模式确定当前块的第一融合条件的方式不做限制。
在一种示例中，将第一帧内预测模式和第二帧内预测模式的索引号差值大于某一个预设值，作为当前块的第一融合条件。例如，第一融合条件为：mode1_idx&mode2_idx>c，其中mode1_idx为第一帧内预测模式的索引号，mode2_idx为第二帧内预测模式的索引号。在帧内预测模式中，例如图5或图6所示的角度预测模式，相邻的角度预测模式对应的预测效果相近，例如，索引号为17的角度预测模式和索引号为18的角度预测模式均接近于水平方向，其预测效果相近。由此可知，当第一帧内预测模式和第二帧内预测模式的索引号差值大于某一个预设值时，说明第一帧内预测模式和第二帧内预测模式为两个差异较大的预测模式，对应的预测效果差别也较大。此时，为了提高当前块的预测效果，则可以通过第一帧内预测模式和第二帧内预测模式进行加权预测，即将第一帧内预测模式和第二帧内预测模式分别预测得到的预测值进行加权，作为当前块的目标预测值，以提高当前块的预测效果。
在一种示例中，将第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值，作为当前块的第一融合条件。例如，当前块的第一融合条件为：mode1_idx&mode2_idx≥d，其中d为第二预设阈值。本申请对第二预设阈值的具体取值不做限制，具体根据实际需要确定，例如第二预设阈值为3或4等。当第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值时，说明第一帧内预测模式和第二帧内预测模式的差异较大，对应的预测效果差别也较大。此时，为了提高当前块的预测效果，则可以通过第一帧内预测模式和第二帧内预测模式进行加权预测，即将第一帧内预测模式和第二帧内预测模式分别预测得到的预测值进行加权，作为当前块的目标预测值，以提高当前块的预测效果。
在该第三种方式中，假设当前块的第一融合条件为第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值，此时，上述S403中根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的目标预测值包括如下步骤S403-C1：
S403-C1、若第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值时，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的目标预测值。
也就是说，当第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值时，说明第一帧内预测模式和第二帧内预测模式的差异较大，对应的预测效果差别也较大，此时，如果使用其中代价最小的一个预测模式进行单独预测时，可能造成预测不准确的问题。为了提高当前块的预测效果，视频解码器在确定第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值时，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的目标预测值。例如，使用第一帧内预测模式对当前块进行预测，得到第一个预测值，使用第二帧内预测模式对当前块进行预测，得到第二个预测值，对第一个预测值和第二个预测值进行加权，得到当前块的目标预测值，例如根据上述公式(1)至公式(3)所示的加权方法，加权运算得到当前块的目标预测值。或者，采用权重矩阵的方式导出第一个预测值和第二个预测值的权重，再根据公式(3)进行加权，得到当前块的目标预测值。例如，视频解码器从GPM的64种权重划分模式中或者AWP存在有56种权重划分模式中选择一种权重划分模式对应的权重分布，作为第一帧内预测模式对应的第一个预测值和第二帧内预测模式对应的第二个预测值的权重。例如，第一帧内预测模式为角度预测模式，则将与第一帧内预测模式的角度重合或近似重合的权重划分模式对应的权重分布，确定为第一个预测值和第二个预测值对应的权重。
在一些实施例中，上述S403还包括如下S403-C2：
S403-C2、若第一帧内预测模式和第二帧内预测模式的索引号差值小于第二预设阈值时，则使用第一帧内预测模式，确定当前块的目标预测值。
本申请实施例中，当第一帧内预测模式和第二帧内预测模式不满足上述确定的当前块的加权融合条件，即第一帧内预测模式和第二帧内预测模式的索引号差值小于第二预设阈值时，说明当前块的第一帧内预测模式和第二帧内预测模式的预测效果近似。此时，使用一个帧内预测模式对当前块进行预测时，可以达到较佳的预测效果。使用加权预测方式，即使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测时，反而会降低当前块的预测效果，例如降低当前块的锐度和颜色鲜明度等，且增加预测复杂度。因此，在该情况下，为了保证当前块的预测质量且降低预测复杂度，当第一帧内预测模式和第二帧内预测模式的索引号差值小于第二预设阈值时，视频解码器使用第一帧内预测模式和第二帧内预测模式中代价最小的一个帧内预测模式进行预测。由上述可知，第一代价小于第二代价，因此视频解码器直接使用第一帧内预测模式对当前块进行预测，将预测得到的预测值，确定为当前块的目标预测值。
在该第三种方式中，视频解码器解码码流，得到第一标志，若第一标志指示使用第一技术时，则视频解码器根据第一帧内预测模式和第二帧内预测模式确定第一融合条件，例如将第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值作为第一融合条件，进而将当前块的第一融合条件作为当前块的加权融合条件。该第三种方式中，若第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值时，说明第一帧内预测模式和第二帧内预测模式的差异较大，对应的预测效果差别也较大。此时，为了提高当前块的预测效果，则将第一帧内预测模式和第二帧内预测模式分别预测得到的预测值进行加权，作为当前块的目标预测值，以提高当前块的预测效果。若第一帧内预测模式和第二帧内预测模式的索引号差值小于第二预设阈值时，说明说明当前块的第一帧内预测模式和第二帧内预测模式的预测效果近似，此时为了保证当前块的预测效果以及降低预测复杂度，则使用第一帧内预测模式，确定当前块的目标预测值。
需要说明的是，上述第三种方式，除了作为图像内容为第一图像内容的当前块的加权融合条件外，还可以作为其他的图像块的加权融合条件。也就是说，可以将上述方式三，作为第一种新的加权融合条件，判断图像块是否需要进行加权融合预测。
本申请实施例，若第一标志指示使用第一技术时，则视频解码器通过上述三种方式中的任意一种方式，确定出当前块的第一融合条件，且将该第一融合条件作为当前块的加权融合条件来判断对当前块是否进行加权预测，在保证当前块的预测效果的同时，降低对当前块进行加权预测的概率，进一步提高了当前块的预测质量。
在一些实施例中，在执行上述S402之前，首先需要判断第一帧内预测模式和第二帧内预设模式的类型，若第一帧内预测模式和第二帧内预测模式中的至少一个为角度预测模式时，才执行上述S402的步骤，即根据当前序列的图像内容，确定当前块的加权融合条件。
在一些实施例中，若第一帧内预测模式和第二帧内预测模式均为非角度预测模式，此时则不执行上述S402的步骤，而是直接根据第一帧内预测模式来确定当前块的目标预测值。
在一些实施例中，通过当前块所在的当前帧的类型，限制是否采用本申请实施例的方法，也就是说，根据当前帧的类型，确定是否执行S402中的根据当前序列的图像内容，确定当前块的加权融合条件的步骤。在该实施例中，规定了有些类型的帧可以使用本申请实施例的方法，有些类型的帧不能使用本申请实施例的方法，进而实现差异化执行。例如，若当前帧的类型为目标帧类型时，则根据当前序列的图像内容，确定当前块的加权融合条件，例如I帧允许使用本申请的技术方案而B帧不允许使用。本申请对目标内类型不做限制，具体根据实际需求确定。可选的，目标帧类型包括I帧、P帧、B帧中的至少一个。
在一些实施例中，通过帧类型和图像块大小，限制是否采用本申请实施例的方法。此时，视频解码器在执行本申请实施例的方法，首先确定当前块所在的当前帧的类型，以及当前块的大小；根据当前帧的类型和当前块的大小，确定是否根据当前序列的图像内容，确定所述当前块的加权融合条件。
需要说明的是，在本申请的实施例中，当前块的大小可以包括当前块的高度和宽度，因此，视频解码器根据当前块的高度和宽度，决定是否执行上述S402的步骤。
示例性的，在本申请中，若所述当前帧的类型为第一帧类型，且当前块的大小大于第一阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
示例性的，在本申请中，若所述当前帧的类型为第二帧类型，且所述当前块的大小大于第二阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。可选的，当前第一帧类型与第二帧类型不相同。可选的，上述第一阈值和第二阈值也不相同。本申请对第一帧类型和第二帧类型的具体类型不做限制，对第一阈值和第二阈值的具体取值也不限制。在一种具体的示例中，若第一帧类型为I帧，第二帧类型为B帧或P帧，则第二阈值与第一阈值 不相同，也就是说，I帧和B帧(或P帧)规定的可适用的块大小可以不相同。
在一些实施例中，还可以通过量化参数，限制是否采用本申请实施例的方法。此时，视频解码器在执行本申请实施例的方法，首先确定解码码流，得到当前块对应的量化参数，例如视频解码器根据帧级允许标志位或序列级QP允许标志位，得到当前块的量化参数，进而根据量化参数，确定是否根据当前序列的图像内容，确定当前块的加权融合条件。
示例性的，若量化参数小于第三阈值，则根据当前序列的图像内容，确定当前块的加权融合条件。本申请对第三阈值的具体取值不做限制，具体根据实际需要确定。
视频解码器根据上述方法，得到当前块的预测值后，解码码流得到当前块的残差值，将预测块与残差块相加，得到当前块的重建块。
本申请实施例的帧内预测方法，视频解码器通过解码码流，确定当前块的第一帧内预测模式和第二帧内预测模式；根据当前序列的图像内容，确定当前块的加权融合条件，加权融合条件用于判断当前块是否通过第一帧内预测模式和第二帧内预测模式进行加权预测；根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的目标预测值。即本申请根据当前序列的图像内容，确定当前块的加权融合条件，并基于该加权融合条件判断是否对当前块进行加权融合预测，可以避免对不需要加权融合预测的图像内容进行加权融合预测时，降低预测质量，引入不必要噪声的问题，进而提高了帧内预测的准确性。
在一些实施例中，本申请提出了一种新的加权融合条件的确定方法，具体是：将第一阈值系数的取值确定为第二预设值，第一阈值系数用于确定加权融合条件；根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及第一阈值系数，确定当前块的加权融合条件。
可选的，上述第一预设值为小于2的正数，例如为1.9或1.95等。
可选的，加权融合条件为第二代价小于所述第一代价与第一阈值系数的乘积。
在该示例中，假设已有的加权融合条件为：cost2<a cost1，而本申请的加权融合条件为：cost2<a2 cost1，其中a2小于a，因此，本申请的加权融合条件更加严格，例如cost2满足已有的加权融合条件时，cost2的取值范围为：cost1<cost2<acost1，cost2满足本申请的加权融合条件时，cost2的取值范围为：cost1<cost2<a2cost1。由于a2小于a，因此，cost2要满足修改后的加权融合条件时，其取值范围变小，进而使得第一帧内预测模式和第二帧内预测模式不容易满足本申请修改后的加权融合条件，这样，使用修改后的加权融合条件进行加权预测判断时，可以降低对第一图像内容的当前块进行加权预测的概率，从而保证了第一图像内容的当前块的预测质量。
视频解码器根据上述方法确定出当前块的加权融合条件后，判断第一帧内预测模式和第二帧内预测模式是否满足该加权融合条件。示例性的，若第二代价小于第一代价与第一阈值系数的乘积，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的目标预测值。示例性的，若第二代价大于或等于第一代价与第一阈值系数的乘积，则使用第一帧内预测模式，确定当前块的目标预测值。
需要说明的是，上述确定当前块的加权融合条件的方法，适用于将任意图像内容的当前块。
下面对本申请提供的帧内预测方法与TIMD技术相结合时的解码过程进行介绍。
图9为本申请实施例提供的帧内预测方法的一种流程示意图，如图9所示，包括：
S501、解码码流，得到TIMD允许标志。
其中，TIMD允许标志用于指示当前解码器是否允许使用TIMD技术。
S502、若TIMD允许标志指示当前解码器允许使用TIMD技术时，解码码流，得到TIMD使能标志。
其中，TIMD使能标志用于指示当前块是否使用TIMD技术。
S503、若TIMD使能标志指示当前块使用TIMD技术时，解码码流，得到第一标志。
其中，第一标志用于指示是否使用第一技术，该第一技术在第一图像内容下使用。
S504、若TIMD使能标志指示当前块使用TIMD技术，且当前块的多个参考重建样本中至少一个参考重建样本存在时，则确定当前块的MPM，并根据MPM，确定当前块的第一帧内预测模式和第二帧内预测模式。
具体参照上述S401的描述，在此不再赘述。
S505、若第一标志指示当前块使用第一技术时，则确定当前块的第一融合条件。
例如，将第一阈值系数的取值修改为第一预设值，根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及修改后的第一阈值系数，确定第一融合条件。
例如，根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，确定当前块的第一融合条件。
例如，根据第一帧内预测模式和第二帧内预测模式，确定第一融合条件。
具体参照上述S402的描述，在此不再赘述。
S506、根据第一融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的目标预测值。
具体参照上述S403的描述，在此不再赘述。
视频解码器根据上述方法，得到当前块的目标预测值后，解码码流得到当前块的残差值，将预测块与残差块相加，得到当前块的重建块。
本申请实施例，通过对TIMD技术中的加权融合条件进行调整，例如根据当前序列的图像内容，确定当前块的加权融合条件，并基于该加权融合条件判断是否对当前块进行加权融合预测，可以避免对不需要加权融合预测的图像内容进行加权融合预测时，降低预测质量，引入不必要噪声的问题，进而提高了帧内预测的准确性。
进一步的，将本申请实施例的方法集成到最新ECM2.0上后，在通测条件全帧内预测(AL)条件下进行测试，测试结果如表3所示。
表3
Figure PCTCN2021142113-appb-000001
值得注意的是，现有JVET组织ECM软件的通测条件中，只有F类序列是屏幕内容编码序列，故本测试使用序列级开关(例如上述的第一标志)，仅在屏幕内容编码情况下允许使用，因此只有class F有性能上的波动。
从上述表3的测试中可以看到，本申请对于全帧内预测模式存在解码性能的提升，且较为稳定，平均有0.08％的解码性能提升。此外，该申请对软硬件的复杂度几乎没有任何影响，从参考软件的解码时间上也可以看出没有程序运行时间上的波动。
上文对本申请实施例的解码方法进行介绍，在此基础上，下面对本申请实施例提供的编码方法进行介绍。
图10为本申请实施例提供的帧内预测方法的一种流程示意图。如图10所示，本申请实施例的方法包括：
S601、确定当前块的第一帧内预测模式和第二帧内预测模式。
在视频编码过程中，视频编码器接收视频流，该视频流由一系列图像帧组成，针对视频流中的每一帧图像进行视频编码，视频编码器对图像帧进行块划分，得到当前块。
在一些实施例中，当前块也称为当前编码块、当前图像块、编码块、当前编码单元、当前待编码块、当前待编码的图像块等。
在块划分时，传统方法划分后的块既包含了当前块位置的色度分量，又包含了当前块位置的亮度分量。而分离树技术(dual tree)可以划分单独分量块，例如单独的亮度块和单独的色度块，其中亮度块可以理解为只包含当前块位置的亮度分量，色度块理解为只包含当前块位置的色度分量。这样相同位置的亮度分量和色度分量可以属于不同的块，划分可以有更大的灵活性。如果分离树用在CU划分中，那么有的CU既包含亮度分量又包含色度分量，有的CU只包含亮度分量，有的CU只包含色度分量。
在一些实施例中，本申请实施例的当前块只包括色度分量，可以理解为色度块。
在一些实施例中，本申请实施例的当前块只包括亮度分量，可以理解为亮度块。
在一些实施例中，该当前块即包括亮度分量又包括色度分量。
需要说明的是，视频编码器确定当前块允许采用两种帧内预测模式进行融合加权预测时，则视频编码器确定第一帧内预测模式和第二帧内预测模式。在判断该第一帧内预测模式和第二帧内预测模式符合加权融合条件时，则使用第一帧内预测模式对当前块进行预测，得到当前块的第一个预测值，使用第二帧内预测模式对当前块进行预测，得到当前块的第二个预测值，将第一个预测值和第二个预测值进行加权融合，得到当前块的第一预测值。
在一些实施例中，若判断第一帧内预测模式和第二帧内预测模式不满足加权融合条件时，则使用第一帧内预测模式和第二帧内预测模式中的一个帧内预测模式，对当前块进行预测，得到当前块的第一预测值。
在一些实施例中，视频编码器确定当前块允许采用两种帧内预测模式进行融合加权预测时，视频编码器在码流中携带第二标志，该第二标志用于指示当前块是否通过第一帧内预测模式和第二帧内预测模式中的至少一个确定第一预测值。若视频编码器使用第一帧内预测模式和第二帧内预测模式中的至少一个确定第一预测值，则将第二标志置为真，例如将第二标志的取值置为1，并将置为真的第二标志写入码流中，例如写入码流头中。这样视频解码器获得码流后，解码该码流，得到第二标志，若该第二标志为真，例如该第二标志的取值为1，则视频解码器确定当前块是通过第一帧内预测模式和第二帧内预测模式中的至少一个确定第一预测值。可选的，视频编码器确定第一帧内预测模式和第二帧内预测模式的方式与视频解码器确定第一帧内预测模式和第二帧内预测模式的方式相同。可以参照上述S401的描述。
若视频编码器不是通过第一帧内预测模式和第二帧内预测模式中的至少一个确定当前块的第一预测值时，则将第二标志置为假，例如将第二标志的取值置为0，并将置为假的第二标志写入码流中，例如写入码流头中。视频解码器解码码流，得到第二标志，若该第二标志为假，例如该第二标志的取值为0，则视频解码器则不确定当前块的第一帧内预测模式和第二帧内预测模式，而是遍历预设的帧内预测模式，确定出代价最小的帧内预测模式对当前块进行预测，得到当前块的第一预测值。
在一种可能的实现方式中，若本申请采用TIMD技术，则上述第二标志可以为TIMD使能标志，例如为sps_timd_enable_flag。也就是说，视频编码器获得TIMD的允许使用标志位，该TIMD的允许使用标志位为序列级标志位。该TIMD的允许使用标志位用于指示当前序列是否允许使用TIMD技术。若视频编码器确定该当前序列允许使用TIMD技术，即TIMD的允许使用标志位为真，例如为1。接着，视频编码器确定当前块的第一帧内预测模式和第二帧内预测模式，并执行本申请实施例的方法，视频编码器采用TIMD技术确定当前块的第一预测值时，则将TIMD使能标志置为真，例如置为1，且写入码流，例如写入码流头。若视频编码器未采用TIMD技术确定当前块的第一预测值时，则将TIMD使能标志置为假，例如置为0，且写入码流，例如写入码流头中。这样视频解码器可以从码流中解析出TIMD使能标志，并根据TIMD使能标志来确定是否使用TIMD技术来确定当前块的第一预测值，进而保证解 码端和编码端的一致，保证预测的可靠性。
本申请中，上述S601中确定当前块的第一帧内预测模式和第二帧内预测模式的方式包括但不限于如下几种：
方式一，遍历预设的帧内预测列表，从中选出代价最小的帧内预测模式作为第一帧内预测模式，选出次小的帧内预测模式作为第二帧内预测模式。
上述预设的帧内预测列表可以包括直流(Direct Current，DC)模式、平面(PLANAR)模式以及角度模式任意一种帧内编码模式等。
在该方式一中，视频编码器，遍历预设的帧内预测列表中的不同帧内预测模式分别对当前块进行预测编码，然后计算多种预测模式下每一种预测模式对应的代价。将最小代价对应的帧内预测模式确定为当前块的第一帧内预测模式，将次小代价对应的帧内预测模式，确定为当前块的第二帧内预测模式。
可选地，使用SAD，或SATD等作为各预测模式的近似代价。可选的，可以使用当前块和当前块的预测值来确定SAD和SATD。例如，使用某一个帧内预测模式对当前块进行预测，得到当前块的预测值，将当前块与当前块的预测值的像素差值，确定为该帧内预测模式对应的SAD。将当前块与当前块的预测值进行相减，得到当前块的残差值，对残差值进行Hadamard变换后再求各元素绝对值之和，进而得到该帧内预测模式对应的SATD。
方式二，根据当前块的MPM确定当前块的第一帧内预测模式和第二帧内预测模式。即上述S601包括如下S601-A1和S601-A2的步骤：
S601-A1、确定当前块的MPM：
S601-A2、根据MPM，确定第一帧内预测模式和第二帧内预测模式。
在帧内预测中可以使用MPM的帧内模式编码技术来提高编解码效率。利用周边已编解码的块的帧内预测模式，以及根据周边已编解码块的帧内预测模式导出的帧内预测模式，如相邻的模式，以及一些常用或使用概率比较高的帧内预测模式，如DC，Planar，Bilinear模式等，构成一个模式列表。参考周边已编解码的块的帧内预测模式利用了空间上的相关性。
由上述可知，MPM根据当前块周围已解码区域的帧内预测模式组成，这样视频编码器获得当前块周围已解码的区域区域中的图像块所使用的帧内预测模式，进而组成当前块的MPM。例如，使用当前块上方、左上、右上等区域的帧内预测模式，构成当前块的MPM。
在一些实施例中，若本申请采用TIMD技术时，则如图7所示，将当前块的右上区域、上方区域、左上区域、左侧区域和左下区域中已编码区域的帧内预测模式，构成当前块的MPM。例如，右上区域在编码时使用的帧内预测模式1，上方区域在编码时使用的帧内预测模式2，左上区域在编码时使用的帧内预测模式3，左侧区域在编码时使用的帧内预测模式2，左下区域在编码时使用的帧内预测模式4，这样，可以确定当前块的MPM中包括帧内预测模式1、帧内预测模式2、帧内预测模式3和帧内预测模式4。
需要说明的是，若当前块的右上区域、上方区域、左上区域、左侧区域和左下区域中有部分区域未编码时，则使用这些区域中已编码区域对应的帧内预测模式构建当前块的MPM。
可选的，若当前块第一个待编码码块，也就是说当前块周围不存在已编码码的区域，此时，可以预设的多个帧内预测模式中选出几个帧内预测模式构建当前块的MPM。
可选的，若当前块为第一待编码块时，则采用上述方式一的方法，遍历预设的帧内预测列表中的每个帧内预测模式，得到代价最小的第一帧内预测模式和代价次小的第二帧内预测模式。
根据上述方法确定出当前块的MPM后，根据该MPM，确定第一帧内预测模式和第二帧内预测模式。为了便于描述，将MPM中的帧内预测模式记为候选帧内预测模式。其中，根据该MPM，确定第一帧内预测模式和第二帧内预测模式的方式包括但不限于如下几种示例：
示例1，将上述MPM中的一个候选帧内预测模式，确定为第一帧内预测模式，将该MPM中除第一帧内预测模式外的一个候选帧内预测模式，确定为第二帧内预测模式。例如，将MPM中的任意一个候选帧内预测模式确定为第一帧内预测模式，将该MPM中除第一帧内预测模式外的任意一个候选预设模式确定为第二帧内预测模式。
示例2，确定使用该MPM中的候选帧内预测模式，对当前块进行预测时的代价；根据该MPM中候选帧内预测模式对应的代价，确定第一帧内预测模式和第二帧内预测模式。例如，使用MPM中的每个候选帧内预测模式对当前块进行预测编码，得到每个候选帧内预测模式对应的代价。接着，根据MPM中每个候选帧内预测模式对应的代价，确定第一帧内预测模式和第二帧内预测模式，例如，将MPM中代价最小的候选帧内预测模式确定为第一帧内预测模式，将MPM中代价次小的候选帧内预测模式确定为第二帧内预测模式。
可选的，上述代价可以为SAD或SATD等，本申请对此不做限制。
该方式二中，通过确定当前块的MPM，并根据MPM中各候选帧内预测模式对当前块进行预测编码时的代价，确定当前块的第一帧内预测模式和第二帧内预测模式，由于MPM中所包括的帧内预测模式较少，进而降低了第一帧内预测模式和第二帧内预测模式的确定复杂度，提高了第一帧内预测模式和第二帧内预测模式的确定速度，进而提升预测效率。
若本申请可以采用TIMD技术时，则采用如下方式三，确定当前块的第一帧内预测模式和第二帧内预测模式。
方式三，基于TIMD技术确定当前块的第一帧内预测模式和第二帧内预测模式。即上述S601包括如下S601-B1和S601-B2的步骤：
S601-B1、获取TIMD允许使用标志，该TIMD允许使用标志用于指示所述当前序列是否允许使用所述TIMD技术；
S601-B2、若该TIMD允许使用标志指示所述当前序列允许使用所述TIMD技术时，则确定所述当前块的第一帧内预测模式和第二帧内预测模式。
由上述可知，TIMD技术是基于模板来导出帧内预测模式，基于此，视频编码器根据IMD允许使用标志确定当前块可以采用TIMD技术时，可以通过对图7所示的当前块的模板进行预测编码，确定出当前块的第一帧内预测模式和 第二帧内预测模式，而不是直接对当前块直接进行预测编码来确定第一帧内预测模式和第二帧内预测模式。由于当前块的模板为已重建区域，可以根据模板的预测值和重建值之间的差异，确定出帧内预测模式的效果，进而可以准确、快速地确定出当前块的第一帧内预测模式和第二帧内预测模式。
其中，上述S601-B2中确定当前块的第一帧内预测模式和第二帧内预测模式的方式包括但不限于如下几种示例：
示例1，遍历预设的帧内预测模式列表，使用帧内预测模式列表中的每个帧内预测模式分别对当前块的模板进行预测编码，得到每个预测模式对应的预测值。接着，将每个预测模式对应的预测值与模板的重建值进行比较，例如，计算预测模式对应的预测值与模板的重建值之间的代价，例如SAD或SATD，将代价最小的预测模式确定为当前块的第一帧内预测模式，将代价次小的预测模式确定为当前块的第二帧内预测模式。
示例2，通过如下S601-B21和S601-B22的步骤确定出当前块的第一帧内预测模式和第二帧内预测模式。
S601-B21、若所述TIMD允许使用标志指示当前序列允许使用TIMD技术，且当前块的多个参考重建样本中至少一个参考重建样本存在时，则确定当前块的MPM：
S601-B22、根据MPM，确定当前块的第一帧内预测模式和第二帧内预测模式。
在该示例二中，当前块的多个参考重建样本可以理解为当前块周围已重建区域，该示例2根据当前块周围多个残差重建样本的帧内预测模式，来确定当前块的MPM。当前块的多个参考重建样本为预先设定好的，例如，将当前块的上方重建区域确定为当前块的一个重建样本，将当前块的左侧重建区域确定为当前块的一个重建样本等。
在一些实施例中，如图7所示，将当前块的右上区域、上方区域、左上区域、左侧区域和左下区域记为当前块的参考重建样本。这些参考重建样本中有些存在，也称为有效，有些可能不存在，即无效，例如，当前块的左侧区域已重建，但是当前块的上方区域未重建，这样可以称为当前块的左侧区域的参考重建样本存在(即有效)，当前块的上方区域的参考重建样本不存在(即无效)。
在该示例2中，若TIMD允许使用标志指示当前序列允许使用TIMD技术，且当前块的多个参考重建样本中至少一个参考重建样本存在时，则根据存在的参考重建样本对应的帧内预测模式，构建当前块的MPM，例如，当前块存在的参考重建样本为K个，在帧内预测时分别使用的帧内预测模式为帧内预测模式1、帧内预测模式2…..，帧内预测模式K，则使用帧内预测模式1、帧内预测模式2…..，以及帧内预测模式K构建当前块的MPM。
根据上述步骤，确定出当前块的MPM后，则根据该MPM，确定当前块的第一帧内预测模式和第二帧内预测模式。
例如，若MPM中的帧内预测模式个数大小大于1，则将MPM中的任意一个帧内预测模式确定为当前块第一帧内预测模式，将MPM中除第一帧内预测模式外的其他任意一个帧内预测模式，确定为当前块的第二帧内预测模式。
在一些实施例中，若MPM中的帧内预测模式的个数等于1，则将MPM中的帧内预测模式确定为第一帧内预测模式，从其他的帧内预测模式中确定出一个，作为当前块的第二帧内预测模式。例如，将其他帧内预测模式中代价最小的帧内预测模式确定为第二帧内预测模式。
在一些实施例中，若MPM中的帧内预测模式的个数等于1，则将MPM中的帧内预测模式确定为第一帧内预测模式，将Planar模式确定为第二帧内预测模式。
在一些实施例中，若MPM中的帧内预测模式的个数等于1，则确定不对当前块进行加权融合预测，使用MPM中的帧内预测模式对当前块进行预测，得到当前块的第一预测值。
在一些实施例中，若MPM中的候选帧内预测模式的个数大于1时，则确定使用MPM中的候选帧内预测模式，对当前块的模板区域进行预测时的代价，根据MPM中候选帧内预测模式对应的代价，确定第一帧内预测模式和第二帧内预测模式。例如，将MPM中代价最小的候选帧内预测模式确定为第一帧内预测模式，将MPM中代价次小的候选帧内预测模式确定为第二帧内预测模式。
可选的，上述代价可以为可以为率失真优化(Rate-Distortion Optimization，RDO)，还可以是SAD或SATD等近似代价。
在一种示例中，上述确定使用MPM中的候选帧内预测模式，对当前块的模板区域进行预测时的代价的过程可以是：确定使用MPM中的候选帧内预测模式，对当前块的模板区域进行预测时的预测值；根据候选帧内预测模式对应的预测值和模板区域的重建值，确定候选帧内预测模式对应的代价。具体是，针对MPM中的一个候选帧内预测模式，得到使用该候选帧内预测模式对当前块的模板区域进行预测时的预测值，由于模板区域为已重建区域，重建值已知。接着，根据该帧内预测模式对应的预测值和模板区域的重建值，确定该候选帧内预测模式对应的代价。例如，将将该帧内预测模式对应的预测值和模板区域的重建值之间的SAD或SATD确定为该候选帧内预测模式的代价。
在一些实施例中，若TIMD允许使用标志指示当前序列允许使用TIMD技术，且当前块的多个参考重建样本均不存在时，视频编码器不确定当前块的第一种帧内预测模式和第二帧内预测模式，而是使用Planar模式对当前块进行预测，得到当前块的第一预测值。
根据上述方式一至方式三中的任意一个，可以确定出当前块的第一帧内预测模式和第二帧内预测模式。
在一些实施例中，上述方式二至方式三中，根据所述最有可能模式列表中候选帧内预测模式对应的代价，确定所述第一帧内预测模式和第二帧内预测模式，包括如下几种方式：
方式1，将最有可能模式列表中代价最小的候选帧内预测模式，确定为第一帧内预测模式，将所述最有可能模式列表中代价次小的候选帧内预测模式，确定为第二帧内预测模式。
方式2，将最有可能模式列表中代价最小的候选帧内预测模式，确定为第一初始模式，将最有可能模式列表中代价次小的候选帧内预测模式，确定为第二初始模式；若第一初始模式和第二初始模式中的至少一个为角度预测模式时，则根据预设的偏移量，对第一初始模式和第二初始模式中的角度预测模式进行偏移处理，得到第一帧内预测模式和第二帧内预测模式。
在一些实施例中，若第一初始模式为角度预测模式时，则以第一初始模式作为中心预测方向，向左和右分别偏移一定角度，得到mode1 +和mode1 -，确定使用mode1 +和mode1 -分别对当前块的模板区域进行预测时的代价，将mode1 +、 mode1 -和第一初始模式中代价最小的预测模式，确定为第一帧内预测模式。
在一些实施例中，若第二初始模式为角度预测模式时，则以第二初始模式作为中心预测方向，向左和右分别偏移一定角度，得到mode2 +和mode2 -，确定使用mode2 +和mode2 -分别对当前块的模板区域进行预测时的代价，将mode2 +、mode2 -和第二初始模式中代价最小的预测模式，确定为第二帧内预测模式。
在一些实施例中，若第一初始模式和第二初始模式均不为角度预测模式时，则将第一初始模式确定为第一帧内预测模式，将第二初始模式，确定为第二帧内预测模式。
根据上述方法，确定出当前块的第一帧内预测模式和第二帧内预测模式后，执行如下S602和S603的步骤。
S602、根据当前序列的图像内容，确定当前块的加权融合条件。
上述加权融合条件用于判断当前块是否通过第一帧内预测模式和第二帧内预测模式进行加权预测。
S603、根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的第一预测值。
在本申请实施例中，视频编码器根据上述S601的步骤得到当前块的第一帧内预测模式和第二帧内预测模式后，并不是直接使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测，而是需要判断第一帧内预测模式和第二帧内预测模式是否满足当前块的加权融合条件。若第一帧内预测模式和第二帧内预测模式满足当前块的加权融合条件时，则使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测，例如使用第一帧内预测模式对当前块进行预测，得到第一个预测值，使用第二帧内预测模式对当前块进行预测，得到第二个预测值，对第一个预测值和第二个预测值进行加权，得到当前块的第一预测值。其中，第一个预测值和第二个预测值进行加权时的权重，可以根据第一帧内预测模式和第二帧内预测模式的代价确定，例如，第一帧内预测模式对当前块进行预测时的代价记为第一代价cost1，第二帧内预测模式对当前块进行预测时的代价记为第二代价cost2，上述第一代价和第二代价可以是SAD或SATD等代价。weight1为第一个预测值对应的权重，weigh2为第二个预测值对应的权重，可选的，weight1＝cost2/(cost1+cost2)，weight2＝1-weight1。这样，根据上述公式(3)将第一个预测值和第二个预测值进行加权，得到当前块的第一预测值。
若第一帧内预测模式和第二帧内预测模式不满足当前块的加权融合条件时，则使用第一帧内预测模式和第二帧内预测模式中的一个，对当前块进行预测，得到当前块的第一预测值。例如，使用第一帧内预测模式和第二帧内预测模式中代价最小的预测模式对当前块进行预测，得到当前块的第一预测值。可选的，由上述S601的部分描述可知，第一帧内预测模式为多个预测模式中代价最小的帧内预测模式，第二帧内预测模式为多个预测模式中代价次小的帧内预测模式，也就是说，第一代价小于第二代价，因此，在第一帧内预测模式和第二帧内预测模式不满足当前块的加权融合条件时，则使用第一帧内预测模式对当前块进行预测，得到当前块的第一预测值。
目前的加权融合条件是固定的，也就是说无论图像内容是什么样的，当前块的加权融合条件固定不变。但是，对于一些图像内容，例如屏幕录制的图像内容，一般都有较为锐化和颜色鲜明的特性，对这些图像内容采用加权融合预测时，由于加权融合预测可以理解为一种模糊预测方法，会降低图像中的锐化和颜色鲜明度，进而降低预测质量，带来了噪声。
为例解决上述技术，本申请根据图像内容来确定当前块的加权融合条件。也就是说，本申请针对图像内容，提供差异化的加权融合条件，不同的图像内容对应的加权融合条件可以不同，进而保证了对需要进行加权融合预测的图像内容进行加权融合预测，以提高预测准确性。对于不需要进行加权融合预测的图像内容不进行加权融合预测，以避免引入不必要的噪声，保证预测质量。
一个序列包括一系列图像，这一系列图像通过是在同一个环境中产生的，因此，一个序列中的图像的图像内容基本一致。因此，本申请通过当前序列的图像内容来确定当前块的加权融合条件，可以理解的是，当前块的图像内容与当前序列的图像内容的类型一致，例如均为屏幕内容，或者摄像头采集的其他内容等。
在一些实施例中，根据当前序列的图像内容，确定当前块的加权融合条件，例如，当前序列的图像内容为第一图像内容时，则确定当前块的加权融合条件为第一融合条件，若当前序列的图像内容为第二图像内容时，则确定当前块的加权融合条件为第二融合条件，若当前序列的图像内容为第三图像内容时，则确定当前块的加权融合条件为第三融合条件......，若当前序列的图像内容为第N图像内容时，则确定当前块的加权融合条件为第N融合条件，具体的，如上述表1所示。
上述表1中表示出了不同的图像内容与不同的加权融合条件对应，上述表1为事先设定的好的。这样视频编码设备在确定出当前序列的图像内容后，在表1中进行查找，将当前序列的图像内容对应的加权融合条件，确定为当前块的加权融合条件。
在本申请的一些实施例中，可以理解为在当前序列的图像内容为第一图像内容时，加权融合条件才可能发生变化，若当前序列的图像内容不是第一图像内容时，则加权融合条件不发生变化。也就是说，若当前序列的图像内容为第一图像内容时，采用的加权融合条件为第一融合条件，若当前序列的图像内容非第一图像内容时，则采用的加权融合条件为第二融合条件。其中第一融合条件与第二融合条件不同。
在一些实施例中，为了提高视频解码器确定当前块的加权融合条件的效率，则视频编码器将第一标志编入码流，该第一标志用于指示是否使用第一技术，该第一技术在第一图像内容下使用。例如当前序列的图像内容为第一图像内容时，则视频编码器将该第一标志置为1后编入码流，若当前序列的图像内容不是第一图像内容时，则视频编码器将该第一标志置为0后编入码流。这样，视频解码器解码码流，得到该第一标志，进而根据该第一标志确定当前块的加权融合条件。
可选的，在码流中增加新字段来表示第一标志。例如，用字段sps_timd_blendoff_flag来表示第一标志，该字段为全新的字段。
可选的，上述第一标志复用当前序列中的第三标志，也就是说，可以复用当前序列中已有的字段，无需增加新的字段，进而节约码字。例如，上述第三字段为帧内块复制(Intra-block copy，简称IBC)使能标志或者为模板匹配预测(Template matching prediction，简称TMP)使能标志等。
在一些实施例中，则上述S602包括如下步骤：
S602-B1、若当前序列的图像内容为第一图像内容时，则确定当前块的第一融合条件；
S602-B2、将第一融合条件确定为当前块的加权融合条件。
在该实施例中，视频编码器获得当前序列的图像内容为第一图像内容时，视频编码器器确定当前块的加权融合条件需要进行修改，无法使用已有的加权融合条件，此时，视频编码器重新为当前块确定加权融合条件。具体是，视频编码器确定当前块的第一融合条件，并将该第一融合条件确定为当前块的加权融合条件。
上述S602-B1中确定当前块的第一融合条件的方法包括但不限于如下几种：
第一种方式：将第一阈值系数的取值修改为第一预设值，根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及修改后的第一阈值系数，确定第一融合条件。
上述第一阈值系数用于确定第一融合条件。
在一些实施例中，上述第一阈值系数具有默认值，例如为2或其他数值，本申请实施例中，若当前序列的图像内容为第一图像内容(例如屏幕录制内容)时，则对该第一阈值系数进行修改，例如从默认值修改为第一预设值，进而根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及修改后的第一阈值系数，确定第一融合条件。
可选的，上述第一预设值小于第一阈值系数的默认值。
可选的，上述第一预设值为小于2的正数，例如为1.9或1.95等。
在一种示例中，将第二代价小于第一代价与修改后的第一阈值系数的乘积。例如，当前块的第一融合条件为：cost2<a1 cost1。
在该示例中，假设第一阈值系数未修改之前的取值为a，修改后的取值为a1，且a大于a1。假设已有的加权融合条件为：cost2<a cost1，而本申请修改后的加权融合条件为：cost2<a1 cost1，由于a1小于a，且cost1小于cost2，因此，本申请修改后的加权融合条件更加严格，例如cost2满足未修改之前的加权融合条件时，cost2的取值范围为：cost1<cost2<acost1，cost2满足修改之前的加权融合条件时，cost2的取值范围为：cost1<cost2<a1cost1。由于a1小于a，因此，cost2要满足修改后的加权融合条件时，其取值范围变小，进而使得第一帧内预测模式和第二帧内预测模式不容易满足本申请修改后的加权融合条件，这样，使用修改后的加权融合条件进行加权预测判断时，可以降低对第一图像内容的当前块进行加权预测的概率，从而保证了第一图像内容的当前块的预测质量。
在该第一种方式中，假设当前块的第一融合条件为cost2<a1 cost1，此时，上述S603中根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的第一预测值包括如下步骤S603-A1：
S603-A1、若第二代价小于第一代价与修改后的第一阈值系数的乘积，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的第一预测值。
也就是说，当cost2<a1 cost1时，说明第一帧内预测模式和第二帧内预测模式满足当前块的加权融合条件，因此，使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测，得到当前块的第一预测值。例如，使用第一帧内预测模式对当前块进行预测，得到第一个预测值，使用第二帧内预测模式对当前块进行预测，得到第二个预测值，对第一个预测值和第二个预测值进行加权，得到当前块的第一预测值，例如根据上述公式(1)至公式(3)所示的加权方法，加权运算得到当前块的第一预测值。
在一些实施例中，上述S603还包括如下S603-A2：
S603-A2、若第二代价大于或等于第一代价与修改后的第一阈值系数的乘积，则使用第一帧内预测模式，确定当前块的第一预测值。
本申请实施例中，当第一帧内预测模式和第二帧内预测模式不满足上述确定的当前块的加权融合条件，即不满足cost2<a1 cost1，也就是说，第二帧内预测模式对应的第二代价大于或等于第一帧内预测模式对应的第一代价与修改后的第一阈值系数的乘积时，视频编码器对当前块不进行加权预测，而是使用第一帧内预测模式和第二帧内预测模式中代价最小的一个帧内预测模式进行预测。由上述可知，第一代价小于第二代价，因此视频编码器直接使用第一帧内预测模式对当前块进行预测，将预测得到的预测值，确定为当前块的第一预测值。
在该第一种方式中，视频编码器获得当前序列的图像内容为第一图像内容时，则视频编码器将第一阈值系数的取值修改为第一预设值，并根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，以及修改后的第一阈值系数，确定第一融合条件，例如将第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积作为第一融合条件，进而将当前块的第一融合条件作为当前块的加权融合条件。该第一种方式中，由于对第一阈值系数改小，使得当前块的加权融合条件更加严格，进而降低了第一帧内预测模式和第二帧内预测模式满足本申请修改后的加权融合条件的概率，可以降低对第一图像内容的当前块进行加权预测的概率，从而保证了第一图像内容的当前块的预测质量。
在一些实施例中，视频编码器还可以通过如下第二种方式来确定当前块的第一融合条件。
第二种方式：根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，确定当前块的第一融合条件。
在该第二种方式中，直接根据第一代价和第二代价，来确定当前块的第一融合条件，简化了确定当前块的第一融合条件的过程，提升了基于该第一融合条件判断是否对当前块进行加权预测的速率，进而提升了编码效率。
本申请对根据第一代价和第二代价确定当前块的第一融合条件的方式不做限制。
在一种示例中，将第一代价和第二代价中的至少一个大于或等于第一预设阈值，作为当前块的第一融合条件。例如，当前块的第一融合条件为：第一代价和第二代价中的至少一个大于或等于第一预设阈值。本申请对第一预设阈值的具体取值不做限制，具体根据实际需求确定。在该示例中，若第一帧内预测模式对应的第一代价和/或第二帧内预测模式对应的第二代价大于或等于第一预设值，说明第一帧内预测模式和/或第二帧内预测模式的预测效率不佳，此时， 为了提高当前块的预测效果，则可以通过第一帧内预测模式和第二帧内预测模式进行加权预测，即将第一帧内预测模式和第二帧内预测模式分别预测得到的预测值进行加权，作为当前块的第一预测值，以提高当前块的预测效果。
在该第二种方式中，假设当前块的第一融合条件为第一代价和第二代价中的至少一个大于或等于第一预设阈值，此时，上述S603中根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的第一预测值包括如下步骤S603-B1：
S603-B1、若第一代价和第二代价中的至少一个大于或等于第一预设阈值时，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的第一预测值。
也就是说，当第一代价和第二代价中的至少一个大于或等于第一预设阈值时，说明当前块的第一帧内预测模式和/或第二帧内预测模式的预测效果不佳，此时，如果使用其中代价最小的一个预测模式进行单独预测时，由于无法保证该最小代价的预测模式的预测效率，可能造成预测不准确的问题。为了提高当前块的预测效果，视频编码器在确定第一代价和第二代价中的至少一个大于或等于第一预设阈值时，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的第一预测值。例如，使用第一帧内预测模式对当前块进行预测，得到第一个预测值，使用第二帧内预测模式对当前块进行预测，得到第二个预测值，对第一个预测值和第二个预测值进行加权，得到当前块的第一预测值，例如根据上述公式(1)至公式(3)所示的加权方法，加权运算得到当前块的第一预测值。
在一些实施例中，上述S603还包括如下S603-B2：
S603-B2、若第一代价和第二代价均小于第一预设阈值时，则使用第一帧内预测模式，确定当前块的第一预测值。
本申请实施例中，当第一帧内预测模式和第二帧内预测模式不满足上述确定的当前块的加权融合条件，即第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价均小于第一预设值时，说明当前块的第一帧内预测模式和第二帧内预测模式的预测效果较佳。此时，使用一个帧内预测模式对当前块进行预测时，可以达到较佳的预测效果。使用加权预测方式，即使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测时，反而会降低当前块的预测效果，例如降低当前块的锐度和颜色鲜明度等。因此，在该情况下，为了保证当前块的预测质量，当第一代价和第二代价均小于第一预设阈值时，视频编码器使用第一帧内预测模式和第二帧内预测模式中代价最小的一个帧内预测模式进行预测。由上述可知，第一代价小于第二代价，因此视频编码器直接使用第一帧内预测模式对当前块进行预测，将预测得到的预测值，确定为当前块的第一预测值。
在该第二种方式中，视频编码器获得当前序列的图像内容为第一图像内容时，则视频编码器根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价确定第一融合条件，例如第一代价和第二代价中的至少一个大于或等于第一预设阈值作为第一融合条件，进而将当前块的第一融合条件作为当前块的加权融合条件。该第二种方式中，若第一代价和第二代价中的至少一个大于或等于第一预设阈值时，说明当前块的第一帧内预测模式和/或第二帧内预测模式的预测效果不佳，为了提高当前块的预测效果，则视频编码器使用第一帧内预测模式和第二帧内预测模式，确定当前块的第一预测值。若第一代价和第二代价均小于第一预设阈值时，说明当前块的第一帧内预测模式和第二帧内预测模式的预测效果较佳，此时为了保证当前块的预测效果以及降低预测复杂度，则使用第一帧内预测模式，确定当前块的第一预测值。
需要说明的是，上述第二种方式，除了作为图像内容为第一图像内容的当前块的加权融合条件外，还可以作为其他的图像块的加权融合条件。也就是说，可以将上述方式二，作为第一种新的加权融合条件，判断图像块是否需要进行加权融合预测。
在一些实施例中，视频编码器还可以通过如下第三种方式来确定当前块的第一融合条件。
第三种方式：根据第一帧内预测模式和第二帧内预测模式，确定第一融合条件。
在该第三种方式中，直接根据第一帧内预测模式和第二帧内预测模式，来确定当前块的第一融合条件，简化了确定当前块的第一融合条件的过程，提升了基于该第一融合条件判断是否对当前块进行加权预测的速率，进而提升了编码效率。
本申请对根据第一帧内预测模式和第二帧内预测模式确定当前块的第一融合条件的方式不做限制。
在一种示例中，将第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值，作为当前块的第一融合条件。例如，当前块的第一融合条件为：mode1_idx&mode2_idx≥d，其中d为第二预设阈值。本申请对第二预设阈值的具体取值不做限制，具体根据实际需要确定，例如第二预设阈值为3或4等。当第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值时，说明第一帧内预测模式和第二帧内预测模式的差异较大，对应的预测效果差别也较大。此时，为了提高当前块的预测效果，则可以通过第一帧内预测模式和第二帧内预测模式进行加权预测，即将第一帧内预测模式和第二帧内预测模式分别预测得到的预测值进行加权，作为当前块的第一预测值，以提高当前块的预测效果。
在该第三种方式中，假设当前块的第一融合条件为第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值，此时，上述S603中根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的第一预测值包括如下步骤S603-C1：
S603-C1、若第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值时，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的第一预测值。
也就是说，当第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值时，说明第一帧内预测模式和第二帧内预测模式的差异较大，对应的预测效果差别也较大，此时，如果使用其中代价最小的一个预测模式进行单独预测时，可能造成预测不准确的问题。为了提高当前块的预测效果，视频编码器在确定第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值时，则使用第一帧内预测模式和第二帧内预测模式，确定当前块的第一预测值。例如，使用第一帧内预测模式对当前块进行预测，得到第一个预测值，使用第二帧内预测模式对当前块进行预测，得到第二个预测值，对第一个预测值和第二个预测值进行加权，得到当前块的第一预测值， 例如根据上述公式(1)至公式(3)所示的加权方法，加权运算得到当前块的第一预测值。
在一些实施例中，上述S603还包括如下S603-C2：
S603-C2、若第一帧内预测模式和第二帧内预测模式的索引号差值小于第二预设阈值时，则使用第一帧内预测模式，确定当前块的第一预测值。
本申请实施例中，当第一帧内预测模式和第二帧内预测模式不满足上述确定的当前块的加权融合条件，即第一帧内预测模式和第二帧内预测模式的索引号差值小于第二预设阈值时，说明当前块的第一帧内预测模式和第二帧内预测模式的预测效果近似。此时，使用一个帧内预测模式对当前块进行预测时，可以达到较佳的预测效果。使用加权预测方式，即使用第一帧内预测模式和第二帧内预测模式对当前块进行加权预测时，反而会降低当前块的预测效果，例如降低当前块的锐度和颜色鲜明度等，且增加预测复杂度。因此，在该情况下，为了保证当前块的预测质量且降低预测复杂度，当第一帧内预测模式和第二帧内预测模式的索引号差值小于第二预设阈值时，视频编码器使用第一帧内预测模式和第二帧内预测模式中代价最小的一个帧内预测模式进行预测。由上述可知，第一代价小于第二代价，因此视频编码器直接使用第一帧内预测模式对当前块进行预测，将预测得到的预测值，确定为当前块的第一预测值。
在该第三种方式中，视频编码器获得当前序列的图像内容为第一图像内容时，则视频编码器根据第一帧内预测模式和第二帧内预测模式确定第一融合条件，例如将第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值作为第一融合条件，进而将当前块的第一融合条件作为当前块的加权融合条件。该第三种方式中，若第一帧内预测模式和第二帧内预测模式的索引号差值大于或等于第二预设阈值时，说明第一帧内预测模式和第二帧内预测模式的差异较大，对应的预测效果差别也较大。此时，为了提高当前块的预测效果，则将第一帧内预测模式和第二帧内预测模式分别预测得到的预测值进行加权，作为当前块的第一预测值，以提高当前块的预测效果。若第一帧内预测模式和第二帧内预测模式的索引号差值小于第二预设阈值时，说明说明当前块的第一帧内预测模式和第二帧内预测模式的预测效果近似，此时为了保证当前块的预测效果以及降低预测复杂度，则使用第一帧内预测模式，确定当前块的第一预测值。
需要说明的是，上述第三种方式，除了作为图像内容为第一图像内容的当前块的加权融合条件外，还可以作为其他的图像块的加权融合条件。也就是说，可以将上述方式三，作为第一种新的加权融合条件，判断图像块是否需要进行加权融合预测。
根据上述方法，可以根据第一帧内预测模式和/或第二帧内预测模式，确定出当前块的第一预测值，接着，执行如下S604的步骤。
S604、根据第一预测值，确定当前块的目标预测值。
在一些实施例中，可以直接将上述当前块的第一预测值，确定为当前块的目标预测值。
在一些实施例中，需要将第一预测值与其他预测模式对应的预测值的代价进行比较，根据代价确定当前块的目标预测值。具体的，上述S604包括如下步骤：
S604-A1、根据第一预测值，确定第一预测值对应的第一编码代价。
上述第一编码代价可以是RDO代价，可选的，还可以是SAD或SATD等近似代价等，本申请对此不做限制。
S604-A2、确定候选预测集中的各帧内预测模式对当前块进行预测时的第二编码代价。
上述候选预测集中包括至少一个帧内预测模式，遍历候选预测集中的各帧内预测模式，使用各帧内预测模式分别对当前块进行编码预测，得到候选预测集中各帧内预测模式分别对应的第二编码代价。
可选的，若上述第一帧内预测模式和第二帧内预测模式是通过MPM确定的，则上述候选预测集中不包括MPM中的帧内预测模式。
S604-A3、将第一编码代价和第二编码代价中最小编码代价对应的预测值，确定为当前块的目标预测值。
在一些实施例中，若第一编码代价为第一编码代价和第二编码代价中的最小编码代价，此时将上述第一预测值，确定为当前块的目标预测值。同时，将第二标志置为真后写入码流，例如将TIMD使能标志置为真，例如置为1后编入码流。
在一些实施例中，若第一编码代价不是第一编码代价和第二编码代价中的最小编码代价，则将第二标志置为假后写入码流，例如将TIMD使能标志置为假，例如置为0后编入码流。其中第二标志用于指示当前块是否通过第一帧内预测模式和第二帧内预测模式中的至少一个确定目标预测值。
本申请实施例的帧内预测方法，视频编码器通过确定当前块的第一帧内预测模式和第二帧内预测模式；根据当前序列的图像内容，确定当前块的加权融合条件，加权融合条件用于判断当前块是否通过第一帧内预测模式和第二帧内预测模式进行加权预测；根据加权融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的第一预测值；根据第一预测值，确定当前块的目标预测值。即本申请根据当前序列的图像内容，确定当前块的加权融合条件，并基于该加权融合条件判断是否对当前块进行加权融合预测，可以避免对不需要加权融合预测的图像内容进行加权融合预测时，降低预测质量，引入不必要噪声的问题，进而提高了帧内预测的准确性。
下面对本申请提供的帧内预测方法与TIMD技术相结合时的解码过程进行介绍。
图11为本申请实施例提供的帧内预测方法的一种流程示意图，如图11所示，包括：
S701、获得DIMD允许标志。
其中，DIMD允许标志用于指示当前解码器是否允许使用DIMD技术。
S702、若TIMD允许标志指示当前解码器允许使用TIMD技术时，且当前块的多个参考重建样本中至少一个参考重建样本存在时，则确定当前块的MPM，并根据MPM，确定当前块的第一帧内预测模式和第二帧内预测模式。
具体参照上述S601的描述，在此不再赘述。
S703、若当前序列的图像内容为第一图像内容时，则确定当前块的第一融合条件。
例如，将第一阈值系数的取值修改为第一预设值，根据第一帧内预测模式对应的第一代价和第二帧内预测模式对 应的第二代价，以及修改后的第一阈值系数，确定第一融合条件。
例如，根据第一帧内预测模式对应的第一代价和第二帧内预测模式对应的第二代价，确定当前块的第一融合条件。
例如，根据第一帧内预测模式和第二帧内预测模式，确定第一融合条件。
具体参照上述S602的描述，在此不再赘述。
S704、根据第一融合条件，以及第一帧内预测模式和第二帧内预测模式中的至少一个，确定当前块的第一预测值。
具体参照上述S603的描述，在此不再赘述。
S705、根据第一预测值，确定TIMD模式对应的第一编码代价。
可选的，上述第一编码代价为率失真代价。
S706、确定候选预测集中的各帧内预测模式对当前块进行预测时的第二编码代价。
S707、若第一编码代价为第一编码代价和第二编码代价中的最小代价时，则将第一预测值确定为当前块的目标预测值，且将TIMD使能标志置为1后编入码流。
其中，TIMD使能标志用于指示当前块是否使用TIMD技术。
S708、若第一编码代价不是第一编码代价和第二编码代价中的最小代价时，则将最小第二编码代价对应的预测值确定为当前块的目标预测值，且将TIMD使能标志置为0后编入码流。
S709、将第一标志置为1后编入码流。
本申请实施例，通过对TIMD技术中的加权融合条件进行调整，例如根据当前序列的图像内容，确定当前块的加权融合条件，并基于该加权融合条件判断是否对当前块进行加权融合预测，可以避免对不需要加权融合预测的图像内容进行加权融合预测时，降低预测质量，引入不必要噪声的问题，进而提高了帧内预测的准确性。
应理解，图8至图11仅为本申请的示例，不应理解为对本申请的限制。
以上结合附图详细描述了本申请的优选实施方式，但是，本申请并不限于上述实施方式中的具体细节，在本申请的技术构思范围内，可以对本申请的技术方案进行多种简单变型，这些简单变型均属于本申请的保护范围。例如，在上述具体实施方式中所描述的各个具体技术特征，在不矛盾的情况下，可以通过任何合适的方式进行组合，为了避免不必要的重复，本申请对各种可能的组合方式不再另行说明。又例如，本申请的各种不同的实施方式之间也可以进行任意组合，只要其不违背本申请的思想，其同样应当视为本申请所公开的内容。
还应理解，在本申请的各种方法实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。另外，本申请实施例中，术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系。具体地，A和/或B可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
上文结合图8至图11，详细描述了本申请的方法实施例，下文结合图12至图14，详细描述本申请的装置实施例。
图12是本申请一实施例提供的帧内预测装置的示意性框图。
如图12所示，帧内预测装置10包括：
解码单元11，用于解码码流，确定当前块的第一帧内预测模式和第二帧内预测模式；
确定单元12，用于根据当前序列的图像内容，确定所述当前块的加权融合条件，所述加权融合条件用于判断所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式进行加权预测；
预测单元13，用于根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值。
在一些实施例中，确定单元12，具体用于解码所述码流，得到第一标志，所述第一标志用于指示是否使用第一技术，所述第一技术在第一图像内容下使用；根据所述第一标志，确定所述当前块的加权融合条件。
在一些实施例中，确定单元12，具体用于若所述第一标志指示使用第一技术时，则确定所述当前块的第一融合条件；将所述第一融合条件确定为所述当前块的加权融合条件。
在一些实施例中，确定单元12，具体用于将第一阈值系数的取值修改为第一预设值，所述第一阈值系数用于确定所述第一融合条件；根据所述第一帧内预测模式对应的第一代价和所述第二帧内预测模式对应的第二代价，以及修改后的所述第一阈值系数，确定所述第一融合条件。
可选的，所述第一融合条件为所述第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积。
在一些实施例中，预测单元13，具体用于若所述第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的目标预测值。
在一些实施例中，预测单元13，具体用于若所述第二代价大于或等于所述第一代价与修改后的所述第一阈值系数的乘积，则使用所述第一帧内预测模式，确定所述当前块的目标预测值。
可选的，所述第一预设值为小于2的正数。
在一些实施例中，确定单元12，具体用于根据所述第一帧内预测模式对应的第一代价和所述第二帧内预测模式对应的第二代价，确定所述第一融合条件。
可选的，所述第一融合条件为所述第一代价和所述第二代价中的至少一个大于或等于第一预设阈值。
在一些实施例中，预测单元13，具体用于若所述第一代价和所述第二代价中的至少一个大于或等于所述第一预设阈值时，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的目标预测值。
在一些实施例中，预测单元13，具体用于若所述第一代价和所述第二代价均小于所述第一预设阈值时，则使用所述第一帧内预测模式，确定所述当前块的目标预测值。
在一些实施例中，确定单元12，具体用于根据所述第一帧内预测模式和所述第二帧内预测模式，确定所述第一融合条件。
可选的，所述第一融合条件为所述第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设 阈值。
在一些实施例中，预测单元13，具体用于若所述第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于所述第二预设阈值时，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的目标预测值。
在一些实施例中，预测单元13，具体用于若所述第一帧内预测模式和所述第二帧内预测模式的索引号差值小于所述第二预设阈值时，则使用所述第一帧内预测模式，确定所述当前块的目标预测值。
在一些实施例中，确定单元12，具体用于若所述第一帧内预测模式和所述第二帧内预测模式中的至少一个为角度预测模式时，则根据当前序列的图像内容，确定所述当前块的加权融合条件。
在一些实施例中，预测单元13，还用于若所述第一帧内预测模式和所述第二帧内预测模式均为非角度预测模式时，则根据所述第一帧内预测模式确定所述当前块的目标预测值。
在一些实施例中，解码单元11，具体用于确定所述当前块的最有可能模式列表：根据所述最有可能模式列表，确定所述第一帧内预测模式和第二帧内预测模式。
在一些实施例中，解码单元11，具体用于将所述最有可能模式列表中的一个候选帧内预测模式，确定为所述第一帧内预测模式；将所述最有可能模式列表中除所述第一帧内预测模式外的一个候选帧内预测模式，确定为所述第二帧内预测模式。
在一些实施例中，解码单元11，具体用于确定使用所述最有可能模式列表中的候选帧内预测模式，对所述当前块进行预测时的代价；根据所述最有可能模式列表中候选帧内预测模式对应的代价，确定所述第一帧内预测模式和第二帧内预测模式。
在一些实施例中，解码单元11，具体用于解码码流，得到基于模板的帧内模式导出TIMD使能标志，所述TIMD使能标志用于指示所述当前块是否采用TIMD技术；若所述TIMD使能标志指示所述当前块使用所述TIMD技术时，则确定所述当前块的第一帧内预测模式和第二帧内预测模式。
在一些实施例中，所述若所述TIMD使能标志指示所述当前块使用所述TIMD技术时，解码单元11，具体用于若所述TIMD使能标志指示所述当前块使用所述TIMD技术，且所述当前块的多个参考重建样本中至少一个参考重建样本存在时，则确定所述当前块的最有可能模式列表：根据所述最有可能模式列表，确定所述当前块的第一帧内预测模式和第二帧内预测模式。
在一些实施例中，解码单元11，具体用于若所述最有可能模式列表中的候选帧内预测模式的个数大于1时，则确定使用所述最有可能模式列表中的候选帧内预测模式，对所述当前块的模板区域进行预测时的代价；根据所述最有可能模式列表中候选帧内预测模式对应的代价，确定所述第一帧内预测模式和第二帧内预测模式。
在一些实施例中，解码单元11，具体用于确定使用所述最有可能模式列表中的候选帧内预测模式，对所述当前块的模板区域进行预测时的预测值；根据所述候选帧内预测模式对应的预测值和所述模板区域的重建值，确定所述候选帧内预测模式对应的代价。
在一些实施例中，解码单元11，具体用于将所述最有可能模式列表中代价最小的候选帧内预测模式，确定为所述第一帧内预测模式；将所述最有可能模式列表中代价次小的候选帧内预测模式，确定为所述第二帧内预测模式。
在一些实施例中，预测单元13，还用于若所述TIMD使能标志指示所述当前块采用所述TIMD技术，且所述当前块的多个参考重建样本均不存在时，则使用Planar模式对所述当前块进行预测，得到所述当前块的目标预测值。
在一些实施例中，解码单元11，具体用于将所述最有可能模式列表中代价最小的候选帧内预测模式，确定为第一初始模式，将所述最有可能模式列表中代价次小的候选帧内预测模式，确定为第二初始模式；若所述第一初始模式和所述第二初始模式中的至少一个为角度预测模式时，则根据预设的偏移量，对所述第一初始模式和所述第二初始模式中的角度预测模式进行偏移处理，得到所述第一帧内预测模式和所述第二帧内预测模式。
在一些实施例中，解码单元11，还用于若所述第一初始模式和第二初始模式均不为角度预测模式时，则将所述第一初始模式确定为所述第一帧内预测模式，将所述第二初始模式，确定为所述第二帧内预测模式。
在一些实施例中，解码单元11，还用于解码码流，得到第二标志，所述第二标志用于指示所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式中的至少一个确定目标预测值；若所述第二标志为真时，确定所述第一帧内预测模式和所述第二帧内预测模式。
可选的，所述第二标志为基于模板的帧内模式导出TIMD使能标志。
在一些实施例中，确定单元12，还用于确定所述当前块所在的当前帧的类型；根据所述当前帧的类型，确定是否根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
在一些实施例中，确定单元12，还用于若所述当前帧的类型为目标帧类型时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
可选的，所述目标帧类型包括I帧、P帧、B帧中的至少一个。
在一些实施例中，确定单元12，还用于确定所述当前块所在的当前帧的类型，以及所述当前块的大小；
根据所述当前帧的类型和所述当前块的大小，确定是否根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
在一些实施例中，确定单元12，还用于若所述当前帧的类型为第一帧类型，且所述当前块的大小大于第一阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件；若所述当前帧的类型为第二帧类型，且所述当前块的大小大于第二阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
可选的，若所述第一帧类型为I帧，所述第二帧类型为B帧或P帧，则所述第二阈值与所述第一阈值不相同。
在一些实施例中，确定单元12，还用于确定所述当前块对应的量化参数；根据所述量化参数，确定是否根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
在一些实施例中，确定单元12，还用于若所述量化参数小于第三阈值，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
可选的，所述第一标志复用所述当前序列的第三标志。
可选的，所述第三标志为序列级的帧内块复制IBC使能标志或者为模板匹配预测TMP使能标志。
应理解，装置实施例与方法实施例可以相互对应，类似的描述可以参照方法实施例。为避免重复，此处不再赘述。具体地，图12所示的装置10可以执行本申请实施例的帧内预测方法，并且装置10中的各个单元的前述和其它操作和/或功能分别为了实现上述帧内预测方法等各个方法中的相应流程，为了简洁，在此不再赘述。
图13是本申请一实施例提供的帧内预测装置的示意性框图。
如图13所示，该帧内预测装置20可包括：
第一确定单元21，用于确定当前块的第一帧内预测模式和第二帧内预测模式；
第二确定单元22，用于根据当前序列的图像内容，确定所述当前块的加权融合条件，所述加权融合条件用于判断所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式进行加权预测；
预测单元23，用于根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值；根据所述第一预测值，确定所述当前块的目标预测值。
在一些实施例中，第二确定单元22，具体用于若所述当前序列的图像内容为第一图像内容时，则确定所述当前块的第一融合条件；将所述第一融合条件确定为所述当前块的加权融合条件。
在一些实施例中，预测单元23，还用于将第一标志写入码流，所述第一标志用于指示是否使用第一技术，所述第一技术在所述第一图像内容下使用。
在一些实施例中，第二确定单元22，具体用于将第一阈值系数的取值修改为第一预设值，所述第一阈值系数用于确定所述第一融合条件；根据所述第一帧内预测模式对应的第一代价和所述第二帧内预测模式对应的第二代价，以及修改后的所述第一阈值系数，确定所述第一融合条件。
可选的，所述第一融合条件为所述第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积。
在一些实施例中，预测单元23，具体用于若所述第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的第一预测值。
在一些实施例中，预测单元23，具体用于若所述第二代价大于或等于所述第一代价与修改后的所述第一阈值系数的乘积，则使用所述第一帧内预测模式，确定所述当前块的第一预测值。
可选的，所述第一预设值为小于2的正数。
在一些实施例中，第二确定单元22，具体用于根据所述第一帧内预测模式对应的第一代价和所述第二帧内预测模式对应的第二代价，确定所述第一融合条件。
可选的，所述第一融合条件为所述第一代价和所述第二代价中的至少一个大于或等于第一预设阈值。
在一些实施例中，预测单元23，具体用于若所述第一代价和所述第二代价中的至少一个大于或等于所述第一预设阈值时，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的第一预测值。
在一些实施例中，预测单元23，具体用于若所述第一代价和所述第二代价均小于所述第一预设阈值时，则使用所述第一帧内预测模式，确定所述当前块的第一预测值。
在一些实施例中，第二确定单元22，具体用于根据所述第一帧内预测模式和所述第二帧内预测模式，确定所述第一融合条件。
可选的，所述第一融合条件为所述第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值。
在一些实施例中，预测单元23，具体用于若所述第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于所述第二预设阈值时，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的第一预测值。
在一些实施例中，预测单元23，具体用于若所述第一帧内预测模式和所述第二帧内预测模式的索引号差值小于所述第二预设阈值时，则使用所述第一帧内预测模式，确定所述当前块的第一预测值。
在一些实施例中，第二确定单元22，具体用于若所述第一帧内预测模式和所述第二帧内预测模式中的至少一个为角度预测模式时，则根据当前序列的图像内容，确定所述当前块的加权融合条件。
在一些实施例中，预测单元23，还用于若所述第一帧内预测模式和所述第二帧内预测模式均为非角度预测模式时，则根据所述第一帧内预测模式确定所述当前块的第一预测值。
在一些实施例中，第一确定单元21，具体用于获取所述当前块的最有可能模式列表：根据所述最有可能模式列表，确定所述第一帧内预测模式和第二帧内预测模式。
在一些实施例中，第一确定单元21，具体用于将所述最有可能模式列表中的一个候选帧内预测模式，确定为所述第一帧内预测模式；将所述最有可能模式列表中除所述第一帧内预测模式外的一个候选帧内预测模式，确定为所述第二帧内预测模式。
在一些实施例中，第一确定单元21，具体用于确定使用所述最有可能模式列表中的候选帧内预测模式，对所述当前块进行预测时的代价；根据所述最有可能模式列表中候选帧内预测模式对应的代价，确定所述第一帧内预测模式和第二帧内预测模式。
在一些实施例中，第一确定单元21，具体用于获取基于模板的帧内模式导出TIMD允许使用标志，所述TIMD允许使用标志用于指示所述当前序列是否允许使用所述TIMD技术；若所述TIMD允许使用标志指示所述当前序列允许使用所述TIMD技术时，则确定所述当前块的第一帧内预测模式和第二帧内预测模式。
在一些实施例中，所述若所述TIMD允许使用标志指示所述当前序列允许使用所述TIMD技术时，第一确定单元21，具体用于若所述TIMD允许使用标志指示所述当前序列允许使用所述TIMD技术，且所述当前块的多个参考重建样本中至少一个参考重建样本存在时，则获取所述当前块的最有可能模式列表：根据所述最有可能模式列表，确定所述当前块的第一帧内预测模式和第二帧内预测模式。
在一些实施例中，第一确定单元21，具体用于若所述最有可能模式列表列表中的候选帧内预测模式的个数大于1时，则确定使用所述最有可能模式列表中的候选帧内预测模式，对所述当前块的模板区域进行预测时的代价；根据所述最有可能模式列表中候选帧内预测模式对应的代价，确定所述第一帧内预测模式和第二帧内预测模式。
在一些实施例中，第一确定单元21，具体用于确定使用所述最有可能模式列表中的候选帧内预测模式，对所述当前块的模板区域进行预测时的预测值；根据所述候选帧内预测模式对应的预测值和所述模板区域的重建值，确定所述候选帧内预测模式对应的代价。
在一些实施例中，第一确定单元21，具体用于将所述最有可能模式列表中代价最小的候选帧内预测模式，确定为所述第一帧内预测模式；将所述最有可能模式列表中代价次小的候选帧内预测模式，确定为所述第二帧内预测模式。
在一些实施例中，预测单元23，还用于若所述TIMD允许使用标志指示所述当前序列允许使用所述TIMD技术，且所述当前块的多个参考重建样本均不存在时，则使用Planar模式对所述当前块进行预测，得到所述当前块的第一预测值。
在一些实施例中，第一确定单元21，还用于将所述最有可能模式列表中代价最小的候选帧内预测模式，确定为第一初始模式，将所述最有可能模式列表中代价次小的候选帧内预测模式，确定为第二初始模式；若所述第一初始模式和所述第二初始模式中的至少一个为角度预测模式时，则根据预设的偏移量，对所述第一初始模式和所述第二初始模式中的角度预测模式进行偏移处理，得到所述第一帧内预测模式和所述第二帧内预测模式。
在一些实施例中，第一确定单元21，还用于若所述第一初始模式和第二初始模式均不为角度预测模式时，则将所述第一初始模式确定为所述第一帧内预测模式，将所述第二初始模式，确定为所述第二帧内预测模式。
在一些实施例中，预测单元23，具体用于根据所述第一预测值，确定所述第一预测值对应的第一编码代价；确定候选预测集中的各帧内预测模式对所述当前块进行预测时的第二编码代价；将所述第一编码代价和所述第二编码代价中最小编码代价对应的预测值，确定为所述当前块的目标预测值。
在一些实施例中，预测单元23，还用于若所述第一编码代价为第一编码代价和第二编码代价中的最小编码代价，则将第二标志置为真后写入码流；若所述第一编码代价不是第一编码代价和第二编码代价中的最小编码代价，则将所述第二标志置为假后写入码流；其中所述第二标志用于指示所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式中的至少一个确定目标预测值。
可选的，所述第二标志为基于模板的帧内模式导出TIMD使能标志。
在一些实施例中，第二确定单元22，还用于确定所述当前块所在的当前帧的类型；根据所述当前帧的类型，确定是否根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
在一些实施例中，第二确定单元22，还用于若所述当前帧的类型为目标帧类型时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
可选的，所述目标帧类型包括I帧、P帧、B帧中的至少一个。
在一些实施例中，第二确定单元22，还用于确定所述当前块所在的当前帧的类型，以及所述当前块的大小；根据所述当前帧的类型和所述当前块的大小，确定是否根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
在一些实施例中，第二确定单元22，还用于若所述当前帧的类型为第一帧类型，且所述当前块的大小大于第一阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件；若所述当前帧的类型为第二帧类型，且所述当前块的大小大于第二阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
可选的，若所述第一帧类型为I帧，所述第二帧类型为B帧或P帧，则所述第二阈值与所述第一阈值不相同。
在一些实施例中，第二确定单元22，还用于确定所述当前块对应的量化参数；根据所述量化参数，确定是否根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
在一些实施例中，第二确定单元22，还用于若所述量化参数小于第三阈值，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
可选的，所述第一标志复用所述当前序列的第三标志。
可选的，所述第三标志为序列级的帧内块复制IBC使能标志或者为模板匹配预测TMP使能标志。
在一些实施例中，预测单元23，还用于将所述第一标志写入所述码流。
应理解，装置实施例与方法实施例可以相互对应，类似的描述可以参照方法实施例。为避免重复，此处不再赘述。具体地，图13所示的装置20可以对应于执行本申请实施例的帧内预测方法中的相应主体，并且装置20中的各个单元的前述和其它操作和/或功能分别为了实现编码方法等各个方法中的相应流程，为了简洁，在此不再赘述。
上文中结合附图从功能单元的角度描述了本申请实施例的装置和系统。应理解，该功能单元可以通过硬件形式实现，也可以通过软件形式的指令实现，还可以通过硬件和软件单元组合实现。具体地，本申请实施例中的方法实施例的各步骤可以通过处理器中的硬件的集成逻辑电路和/或软件形式的指令完成，结合本申请实施例公开的方法的步骤可以直接体现为硬件译码处理器执行完成，或者用译码处理器中的硬件及软件单元组合执行完成。可选地，软件单元可以位于随机存储器，闪存、只读存储器、可编程只读存储器、电可擦写可编程存储器、寄存器等本领域的成熟的存储介质中。该存储介质位于存储器，处理器读取存储器中的信息，结合其硬件完成上述方法实施例中的步骤。
图14是本申请实施例提供的电子设备的示意性框图。
如图14所示，该电子设备30可以为本申请实施例所述的视频编码器，或者视频解码器，该电子设备30可包括：
存储器33和处理器32，该存储器33用于存储计算机程序34，并将该程序代码34传输给该处理器32。换言之，该处理器32可以从存储器33中调用并运行计算机程序34，以实现本申请实施例中的方法。
例如，该处理器32可用于根据该计算机程序34中的指令执行上述方法200中的步骤。
在本申请的一些实施例中，该处理器32可以包括但不限于：
通用处理器、数字信号处理器(Digital Signal Processor，DSP)、专用集成电路(Application Specific Integrated Circuit， ASIC)、现场可编程门阵列(Field Programmable Gate Array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等等。
在本申请的一些实施例中，该存储器33包括但不限于：
易失性存储器和/或非易失性存储器。其中，非易失性存储器可以是只读存储器(Read-Only Memory，ROM)、可编程只读存储器(Programmable ROM，PROM)、可擦除可编程只读存储器(Erasable PROM，EPROM)、电可擦除可编程只读存储器(Electrically EPROM，EEPROM)或闪存。易失性存储器可以是随机存取存储器(Random Access Memory，RAM)，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的RAM可用，例如静态随机存取存储器(Static RAM，SRAM)、动态随机存取存储器(Dynamic RAM，DRAM)、同步动态随机存取存储器(Synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存取存储器(Double Data Rate SDRAM，DDR SDRAM)、增强型同步动态随机存取存储器(Enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(synch link DRAM，SLDRAM)和直接内存总线随机存取存储器(Direct Rambus RAM，DR RAM)。
在本申请的一些实施例中，该计算机程序34可以被分割成一个或多个单元，该一个或者多个单元被存储在该存储器33中，并由该处理器32执行，以完成本申请提供的方法。该一个或多个单元可以是能够完成特定功能的一系列计算机程序指令段，该指令段用于描述该计算机程序34在该电子设备30中的执行过程。
如图14所示，该电子设备30还可包括：
收发器33，该收发器33可连接至该处理器32或存储器33。
其中，处理器32可以控制该收发器33与其他设备进行通信，具体地，可以向其他设备发送信息或数据，或接收其他设备发送的信息或数据。收发器33可以包括发射机和接收机。收发器33还可以进一步包括天线，天线的数量可以为一个或多个。
应当理解，该电子设备30中的各个组件通过总线系统相连，其中，总线系统除包括数据总线之外，还包括电源总线、控制总线和状态信号总线。
图15是本申请实施例提供的视频编解码系统的示意性框图。
如图15所示，该视频编解码系统40可包括：视频编码器41和视频解码器42，其中视频编码器41用于执行本申请实施例涉及的视频编码方法，视频解码器42用于执行本申请实施例涉及的视频解码方法。
本申请还提供了一种计算机存储介质，其上存储有计算机程序，该计算机程序被计算机执行时使得该计算机能够执行上述方法实施例的方法。或者说，本申请实施例还提供一种包含指令的计算机程序产品，该指令被计算机执行时使得计算机执行上述方法实施例的方法。
本申请还提供了一种码流，该码流是通过上述编码方式生成的。可选的，该码流中包括第一标志。
当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。该计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行该计算机程序指令时，全部或部分地产生按照本申请实施例该的流程或功能。该计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。该计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，该计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(digital subscriber line，DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。该计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。该可用介质可以是磁性介质(例如，软盘、硬盘、磁带)、光介质(例如数字视频光盘(digital video disc，DVD))、或者半导体介质(例如固态硬盘(solid state disk，SSD))等。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，该单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。例如，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
以上内容，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以该权利要求的保护范围为准。

Claims (64)

  1. 一种帧内预测方法，其特征在于，包括：
    解码码流，确定当前块的第一帧内预测模式和第二帧内预测模式；
    根据当前序列的图像内容，确定所述当前块的加权融合条件，所述加权融合条件用于判断所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式进行加权预测；
    根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值。
  2. 根据权利要求1所述的方法，其特征在于，所述根据当前序列的图像内容，确定所述当前块的加权融合条件，包括：
    解码所述码流，得到第一标志，所述第一标志用于指示是否使用第一技术，所述第一技术在第一图像内容下使用；
    根据所述第一标志，确定所述当前块的加权融合条件。
  3. 根据权利要求2所述的方法，其特征在于，所述根据所述第一标志，确定所述当前块的加权融合条件，包括：
    若所述第一标志指示使用所述第一技术时，则确定所述当前块的第一融合条件；
    将所述第一融合条件确定为所述当前块的加权融合条件。
  4. 根据权利要求3所述的方法，其特征在于，所述确定所述当前块的第一融合条件，包括：
    将第一阈值系数的取值修改为第一预设值，所述第一阈值系数用于确定所述第一融合条件；
    根据所述第一帧内预测模式对应的第一代价和所述第二帧内预测模式对应的第二代价，以及修改后的所述第一阈值系数，确定所述第一融合条件。
  5. 根据权利要求4所述的方法，其特征在于，所述第一融合条件为所述第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积。
  6. 根据权利要求5所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值，包括：
    若所述第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的目标预测值。
  7. 根据权利要求5所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值，包括：
    若所述第二代价大于或等于所述第一代价与修改后的所述第一阈值系数的乘积，则使用所述第一帧内预测模式，确定所述当前块的目标预测值。
  8. 根据权利要求3所述的方法，其特征在于，所述确定所述当前块的第一融合条件，包括：
    根据所述第一帧内预测模式对应的第一代价和所述第二帧内预测模式对应的第二代价，确定所述第一融合条件。
  9. 根据权利要求8所述的方法，其特征在于，所述第一融合条件为所述第一代价和所述第二代价中的至少一个大于或等于第一预设阈值。
  10. 根据权利要求9所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值，包括：
    若所述第一代价和所述第二代价中的至少一个大于或等于所述第一预设阈值时，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的目标预测值。
  11. 根据权利要求9所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和/或所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值，包括：
    若所述第一代价和所述第二代价均小于所述第一预设阈值时，则使用所述第一帧内预测模式，确定所述当前块的目标预测值。
  12. 根据权利要求3所述的方法，其特征在于，所述确定所述当前块的第一融合条件，包括：
    根据所述第一帧内预测模式和所述第二帧内预测模式，确定所述第一融合条件。
  13. 根据权利要求12所述的方法，其特征在于，所述第一融合条件为所述第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值。
  14. 根据权利要求13所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值，包括：
    若所述第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于所述第二预设阈值时，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的目标预测值。
  15. 根据权利要求13所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值，包括：
    若所述第一帧内预测模式和所述第二帧内预测模式的索引号差值小于所述第二预设阈值时，则使用所述第一帧内预测模式，确定所述当前块的目标预测值。
  16. 根据权利要求1-15任一项所述的方法，其特征在于，所述根据当前序列的图像内容，确定所述当前块的加权融合条件，包括：
    若所述第一帧内预测模式和所述第二帧内预测模式中的至少一个为角度预测模式时，则根据当前序列的图像内容，确定所述当前块的加权融合条件。
  17. 根据权利要求1-15任一项所述的方法，其特征在于，所述方法还包括：
    若所述第一帧内预测模式和所述第二帧内预测模式均为非角度预测模式时，则根据所述第一帧内预测模式确定所述当前块的目标预测值。
  18. 根据权利要求1-15任一项所述的方法，其特征在于，所述确定当前块的第一帧内预测模式和第二帧内预测模式，包括：
    确定所述当前块的最有可能模式列表：
    根据所述最有可能模式列表，确定所述第一帧内预测模式和第二帧内预测模式。
  19. 根据权利要求1-15任一项所述的方法，其特征在于，所述确定当前块的第一帧内预测模式和第二帧内预测模式，包括：
    解码码流，得到基于模板的帧内模式导出TIMD使能标志，所述TIMD使能标志用于指示所述当前块是否采用TIMD技术；
    若所述TIMD使能标志指示所述当前块使用所述TIMD技术，且所述当前块的多个参考重建样本中至少一个参考重建样本存在时，则确定所述当前块的最有可能模式列表；
    根据所述最有可能模式列表，确定所述当前块的第一帧内预测模式和第二帧内预测模式。
  20. 根据权利要求19所述的方法，其特征在于，所述根据所述最有可能模式，确定所述第一帧内预测模式和第二帧内预测模式，包括：
    将所述最有可能模式列表中的一个候选帧内预测模式，确定为所述第一帧内预测模式；
    将所述最有可能模式列表中除所述第一帧内预测模式外的一个候选帧内预测模式，确定为所述第二帧内预测模式。
  21. 根据权利要求19所述的方法，其特征在于，所述根据所述最有可能模式列表中候选帧内预测模式对应的代价，确定所述第一帧内预测模式和第二帧内预测模式，包括：
    将所述最有可能模式列表中代价最小的帧内预测模式，确定为所述第一帧内预测模式；
    将所述最有可能模式列表中代价次小的帧内预测模式，确定为所述第二帧内预测模式。
  22. 根据权利要求19所述的方法，其特征在于，所述方法还包括：
    若所述TIMD使能标志指示所述当前块采用所述TIMD技术，且所述当前块的多个参考重建样本均不存在时，则使用Planar模式对所述当前块进行预测，得到所述当前块的目标预测值。
  23. 根据权利要求1-15任一项所述的方法，其特征在于，所述方法还包括：
    解码码流，得到第二标志，所述第二标志用于指示所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式中的至少一个确定目标预测值；
    若所述第二标志为真时，确定所述第一帧内预测模式和所述第二帧内预测模式。
  24. 根据权利要求23所述的方法，其特征在于，所述第二标志为基于模板的帧内模式导出TIMD使能标志。
  25. 根据权利要求1-15任一项所述的方法，其特征在于，所述方法还包括：
    确定所述当前块所在的当前帧的类型；
    若所述当前帧的类型为目标帧类型时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件，所述目标帧类型包括I帧、P帧、B帧中的至少一个。
  26. 根据权利要求1-15任一项所述的方法，其特征在于，所述方法还包括：
    确定所述当前块所在的当前帧的类型，以及所述当前块的大小；
    若所述当前帧的类型为第一帧类型，且所述当前块的大小大于第一阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件；
    若所述当前帧的类型为第二帧类型，且所述当前块的大小大于第二阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
  27. 根据权利要求1-15任一项所述的方法，其特征在于，所述方法还包括：
    确定所述当前块对应的量化参数；
    若所述量化参数小于第三阈值，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
  28. 根据权利要求3-15任一项所述的方法，其特征在于，所述第一标志复用所述当前序列的第三标志，所述第三标志为序列级的帧内块复制IBC使能标志或者为模板匹配预测TMP使能标志。
  29. 一种帧内预测方法，其特征在于，包括：
    确定当前块的第一帧内预测模式和第二帧内预测模式；
    根据当前序列的图像内容，确定所述当前块的加权融合条件，所述加权融合条件用于判断所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式进行加权预测；
    根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值；
    根据所述第一预测值，确定所述当前块的目标预测值。
  30. 根据权利要求29所述的方法，其特征在于，所述根据当前序列的图像内容，确定所述当前块的加权融合条件，包括：
    若所述当前序列的图像内容为第一图像内容时，则确定所述当前块的第一融合条件；
    将所述第一融合条件确定为所述当前块的加权融合条件。
  31. 根据权利要求30所述的方法，其特征在于，所述方法还包括：
    将第一标志写入码流，所述第一标志用于指示是否使用第一技术，所述第一技术在所述第一图像内容下使用。
  32. 根据权利要求30所述的方法，其特征在于，所述确定所述当前块的第一融合条件，包括：
    将第一阈值系数的取值修改为第一预设值，所述第一阈值系数用于确定所述第一融合条件；
    根据所述第一帧内预测模式对应的第一代价和所述第二帧内预测模式对应的第二代价，以及修改后的所述第一阈值系数，确定所述第一融合条件。
  33. 根据权利要求32所述的方法，其特征在于，所述第一融合条件为所述第二代价小于所述第一代价与修改后的 所述第一阈值系数的乘积。
  34. 根据权利要求32所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值，包括：
    若所述第二代价小于所述第一代价与修改后的所述第一阈值系数的乘积，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的第一预测值。
  35. 根据权利要求33所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值，包括：
    若所述第二代价大于或等于所述第一代价与修改后的所述第一阈值系数的乘积，则使用所述第一帧内预测模式，确定所述当前块的第一预测值。
  36. 根据权利要求30所述的方法，其特征在于，所述确定所述当前块的第一融合条件，包括：
    根据所述第一帧内预测模式对应的第一代价和所述第二帧内预测模式对应的第二代价，确定所述第一融合条件。
  37. 根据权利要求36所述的方法，其特征在于，所述第一融合条件为所述第一代价和所述第二代价中的至少一个大于或等于第一预设阈值。
  38. 根据权利要求36所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值，包括：
    若所述第一代价和所述第二代价中的至少一个大于或等于所述第一预设阈值时，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的第一预测值。
  39. 根据权利要求37所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和/或所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值，包括：
    若所述第一代价和所述第二代价均小于所述第一预设阈值时，则使用所述第一帧内预测模式，确定所述当前块的第一预测值。
  40. 根据权利要求30所述的方法，其特征在于，所述确定所述当前块的第一融合条件，包括：
    根据所述第一帧内预测模式和所述第二帧内预测模式，确定所述第一融合条件。
  41. 根据权利要求40所述的方法，其特征在于，所述第一融合条件为所述第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于第二预设阈值。
  42. 根据权利要求41所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值，包括：
    若所述第一帧内预测模式和所述第二帧内预测模式的索引号差值大于或等于所述第二预设阈值时，则使用所述第一帧内预测模式和所述第二帧内预测模式，确定所述当前块的第一预测值。
  43. 根据权利要求41所述的方法，其特征在于，所述根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值，包括：
    若所述第一帧内预测模式和所述第二帧内预测模式的索引号差值小于所述第二预设阈值时，则使用所述第一帧内预测模式，确定所述当前块的第一预测值。
  44. 根据权利要求29-43任一项所述的方法，其特征在于，所述根据当前序列的图像内容，确定所述当前块的加权融合条件，包括：
    若所述第一帧内预测模式和所述第二帧内预测模式中的至少一个为角度预测模式时，则根据当前序列的图像内容，确定所述当前块的加权融合条件。
  45. 根据权利要求29-43任一项所述的方法，其特征在于，所述方法还包括：
    若所述第一帧内预测模式和所述第二帧内预测模式均为非角度预测模式时，则根据所述第一帧内预测模式确定所述当前块的第一预测值。
  46. 根据权利要求29-43任一项所述的方法，其特征在于，所述确定当前块的第一帧内预测模式和第二帧内预测模式，包括：
    获取所述当前块的最有可能模式列表：
    根据所述最有可能模式列表，确定所述第一帧内预测模式和第二帧内预测模式。
  47. 根据权利要求29-43任一项所述的方法，其特征在于，所述确定当前块的第一帧内预测模式和第二帧内预测模式，包括：
    获取基于模板的帧内模式导出TIMD允许使用标志，所述TIMD允许使用标志用于指示所述当前序列是否允许使用所述TIMD技术；
    若所述TIMD允许使用标志指示所述当前序列允许使用所述TIMD技术，且所述当前块的多个参考重建样本中至少一个参考重建样本存在时，则获取所述当前块的最有可能模式列表：
    根据所述最有可能模式列表，确定所述当前块的第一帧内预测模式和第二帧内预测模式。
  48. 根据权利要求47所述的方法，其特征在于，所述根据所述最有可能模式列表，确定所述第一帧内预测模式和第二帧内预测模式，包括：
    将所述最有可能模式列表中的一个候选帧内预测模式，确定为所述第一帧内预测模式；
    将所述最有可能模式列表中除所述第一帧内预测模式外的一个候选帧内预测模式，确定为所述第二帧内预测模式。
  49. 根据权利要求47所述的方法，其特征在于，所述根据所述最有可能模式列表，确定所述第一帧内预测模式和第二帧内预测模式，包括：
    将所述最有可能模式列表中代价最小的帧内预测模式，确定为所述第一帧内预测模式；
    将所述最有可能模式列表中代价次小的帧内预测模式，确定为所述第二帧内预测模式。
  50. 根据权利要求47所述的方法，其特征在于，所述方法还包括：
    若所述TIMD允许使用标志指示所述当前序列允许使用所述TIMD技术，且所述当前块的多个参考重建样本均不存在时，则使用Planar模式对所述当前块进行预测，得到所述当前块的第一预测值。
  51. 根据权利要求29-43任一项所述的方法，其特征在于，所述根据所述当前块的第一预测值，确定所述当前块的目标预测值，包括：
    根据所述第一预测值，确定所述第一预测值对应的第一编码代价；
    确定候选预测集中的各帧内预测模式对所述当前块进行预测时的第二编码代价；
    将所述第一编码代价和所述第二编码代价中最小编码代价对应的预测值，确定为所述当前块的目标预测值。
  52. 根据权利要求51所述的方法，其特征在于，所述方法还包括：
    若所述第一编码代价为所述第一编码代价和所述第二编码代价中的最小编码代价，则将第二标志置为真后写入码流；
    若所述第一编码代价不是所述第一编码代价和所述第二编码代价中的最小编码代价，则将所述第二标志置为假后写入码流；
    其中所述第二标志用于指示所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式中的至少一个确定目标预测值。
  53. 根据权利要求52所述的方法，其特征在于，所述第二标志为基于模板的帧内模式导出TIMD使能标志。
  54. 根据权利要求29-43任一项所述的方法，其特征在于，所述方法还包括：
    确定所述当前块所在的当前帧的类型；
    若所述当前帧的类型为目标帧类型时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件，所述目标帧类型包括I帧、P帧、B帧中的至少一个。
  55. 根据权利要求29-43任一项所述的方法，其特征在于，所述方法还包括：
    确定所述当前块所在的当前帧的类型，以及所述当前块的大小；
    若所述当前帧的类型为第一帧类型，且所述当前块的大小大于第一阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件；
    若所述当前帧的类型为第二帧类型，且所述当前块的大小大于第二阈值时，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
  56. 根据权利要求29-43任一项所述的方法，其特征在于，所述方法还包括：
    确定所述当前块对应的量化参数；
    若所述量化参数小于第三阈值，则根据所述当前序列的图像内容，确定所述当前块的加权融合条件。
  57. 根据权利要求31所述的方法，其特征在于，所述第一标志复用所述当前序列的第三标志，所述第三标志为序列级的帧内块复制IBC使能标志或者为模板匹配预测TMP使能标志。
  58. 一种帧内预测装置，其特征在于，包括：
    解码单元，用于解码码流，确定当前块的第一帧内预测模式和第二帧内预测模式；
    确定单元，用于根据当前序列的图像内容，确定所述当前块的加权融合条件，所述加权融合条件用于判断所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式进行加权预测；
    预测单元，用于根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的目标预测值。
  59. 一种帧内预测装置，其特征在于，包括：
    第一确定单元，用于确定当前块的第一帧内预测模式和第二帧内预测模式；
    第二确定单元，用于根据当前序列的图像内容，确定所述当前块的加权融合条件，所述加权融合条件用于判断所述当前块是否通过所述第一帧内预测模式和所述第二帧内预测模式进行加权预测；
    预测单元，用于根据所述加权融合条件，以及所述第一帧内预测模式和所述第二帧内预测模式中的至少一个，确定所述当前块的第一预测值；根据所述第一预测值，确定所述当前块的目标预测值。
  60. 一种视频解码器，其特征在于，包括处理器和存储器；
    所示存储器用于存储计算机程序；
    所述处理器用于调用并运行所述存储器中存储的计算机程序，以实现上述权利要求1至28任一项所述的方法。
  61. 一种视频编码器，其特征在于，包括处理器和存储器；
    所示存储器用于存储计算机程序；
    所述处理器用于调用并运行所述存储器中存储的计算机程序，以实现如上述权利要求29至57任一项所述的方法。
  62. 一种视频编解码系统，其特征在于，包括：视频编码器和视频解码器，所述视频解码器用于实现上述权利要求1至28任一项所述的方法，所述视频编码器用于实现如上述权利要求29至57任一项所述的方法。
  63. 一种计算机可读存储介质，其特征在于，用于存储计算机程序；
    所述计算机程序使得计算机执行如上述权利要求1至28或29至57任一项所述的方法。
  64. 一种码流，其特征在于，所述码流是通过如上述权利要求29至57任一项所述的方法生成的。
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104737537A (zh) * 2012-09-07 2015-06-24 高通股份有限公司 用于可缩放视频译码的加权预测模式
US20200221084A1 (en) * 2017-06-19 2020-07-09 Lg Electronics Inc. Intra prediction mode based image processing method, and apparatus therefor
CN111434109A (zh) * 2017-11-28 2020-07-17 韩国电子通信研究院 图像编码/解码方法和装置以及存储有比特流的记录介质
US20210352273A1 (en) * 2018-09-19 2021-11-11 Electronics And Telecommunications Research Institute Intra prediction mode encoding/decoding method and device, and recording medium in which bitstream is stored

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104737537A (zh) * 2012-09-07 2015-06-24 高通股份有限公司 用于可缩放视频译码的加权预测模式
US20200221084A1 (en) * 2017-06-19 2020-07-09 Lg Electronics Inc. Intra prediction mode based image processing method, and apparatus therefor
CN111434109A (zh) * 2017-11-28 2020-07-17 韩国电子通信研究院 图像编码/解码方法和装置以及存储有比特流的记录介质
US20210352273A1 (en) * 2018-09-19 2021-11-11 Electronics And Telecommunications Research Institute Intra prediction mode encoding/decoding method and device, and recording medium in which bitstream is stored

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