WO2020043136A1 - 图像划分方法及装置 - Google Patents

图像划分方法及装置 Download PDF

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Publication number
WO2020043136A1
WO2020043136A1 PCT/CN2019/103094 CN2019103094W WO2020043136A1 WO 2020043136 A1 WO2020043136 A1 WO 2020043136A1 CN 2019103094 W CN2019103094 W CN 2019103094W WO 2020043136 A1 WO2020043136 A1 WO 2020043136A1
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WO
WIPO (PCT)
Prior art keywords
current node
block
node
prediction mode
chroma
Prior art date
Application number
PCT/CN2019/103094
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English (en)
French (fr)
Inventor
赵寅
杨海涛
陈建乐
张恋
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Priority claimed from CN201910191131.5A external-priority patent/CN110868590B/zh
Priority claimed from CN201910696741.0A external-priority patent/CN111669583A/zh
Priority to ES19855934T priority Critical patent/ES2966509T3/es
Priority to BR112021003269-0A priority patent/BR112021003269A2/pt
Priority to KR1020247003066A priority patent/KR20240017109A/ko
Priority to AU2019333452A priority patent/AU2019333452B2/en
Priority to CA3110477A priority patent/CA3110477C/en
Priority to EP23200770.8A priority patent/EP4387224A1/en
Priority to NZ773632A priority patent/NZ773632A/en
Priority to MX2021002396A priority patent/MX2021002396A/es
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to JP2021510741A priority patent/JP7204891B2/ja
Priority to EP19855934.6A priority patent/EP3836542B1/en
Priority to KR1020217008065A priority patent/KR102631517B1/ko
Publication of WO2020043136A1 publication Critical patent/WO2020043136A1/zh
Priority to PH12021550378A priority patent/PH12021550378A1/en
Priority to US17/187,184 priority patent/US11323708B2/en
Priority to ZA2021/01354A priority patent/ZA202101354B/en
Priority to IL281144A priority patent/IL281144A/en
Priority to US17/734,829 priority patent/US11758134B2/en
Priority to JP2022212121A priority patent/JP2023038229A/ja
Priority to US18/360,639 priority patent/US20230370597A1/en
Priority to AU2023229600A priority patent/AU2023229600A1/en

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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
    • H04N19/107—Selection of coding mode or of prediction mode between spatial and temporal predictive coding, e.g. picture refresh

Definitions

  • the present application relates to the field of video encoding and decoding, and more particularly, to a method and device for picture partitioning.
  • Video codecs are widely used in digital video applications, such as broadcast digital TV, video distribution on the Internet and mobile networks, real-time conversation applications such as video chat and video conferencing, DVD and Blu-ray discs, video content capture and editing systems, and camcorders Security applications.
  • Each picture of a video sequence is usually partitioned into a set of non-overlapping blocks, usually encoded at the block level.
  • prediction blocks are generated by spatial (intra-picture) prediction and temporal (inter-picture) prediction.
  • the prediction modes may include an intra prediction mode (spatial prediction) and an inter prediction mode (temporal prediction).
  • the intra prediction mode set may include 35 different intra prediction modes, for example, a non-directional mode such as a DC (or average) mode and a planar mode; or a directional mode as defined in H.265; or Includes 67 different intra-prediction modes, such as non-directional modes such as DC (or average) mode and planar mode; or directional modes as defined in the developing H.266.
  • the set of inter prediction modes depends on the available reference pictures and other inter prediction parameters, such as whether to use the entire reference picture or only a part of the reference picture.
  • the existing video is generally a color video, which contains a chrominance component in addition to a luminance component. Therefore, in addition to encoding and decoding the luminance component, it is also necessary to encode and decode the chrominance component. However, the encoding and decoding efficiency is relatively low in the prior art.
  • the embodiments of the present application (or the present disclosure) provide an apparatus and method for image division.
  • an embodiment of the present invention relates to a method for image division.
  • the method is performed by a device that decodes or encodes a video stream.
  • the method includes determining a division method of a current node, the current node including a luma block and a chroma block; and determining that the chroma block of the current node is no longer based on the division method of the current node and the size of the current node. Dividing; and when the chroma blocks of the current node are no longer divided, dividing the luma blocks of the current node according to the current node's division mode.
  • the method when the chrominance block of the current node is no longer divided, the method can only divide the luma block of the current node, thereby improving the encoding and decoding efficiency and reducing the maximum throughput of the codec. Facilitate the implementation of codecs.
  • an embodiment of the present invention relates to an apparatus for decoding a video stream, including a processor and a memory.
  • the memory stores instructions that cause the processor to perform the method according to the first aspect.
  • an embodiment of the present invention relates to an apparatus for encoding a video stream, including a processor and a memory.
  • the memory stores instructions that cause the processor to perform the method according to the first aspect.
  • a computer-readable storage medium which stores instructions thereon, which, when executed, cause one or more processors to encode video data.
  • the instructions cause the one or more processors to perform a method according to any possible embodiment of the first aspect.
  • embodiments of the present invention relate to a computer program including program code that, when run on a computer, performs a method according to any possible embodiment of the first aspect.
  • FIG. 1A shows a block diagram of an example of a video encoding system for implementing an embodiment of the present invention
  • FIG. 1B shows a block diagram of an example of a video encoding system including any one or both of the encoder 20 of FIG. 2 and the decoder 30 of FIG. 3;
  • FIG. 2 is a block diagram showing an example structure of a video encoder for implementing an embodiment of the present invention
  • FIG. 3 is a block diagram showing an example structure of a video decoder for implementing an embodiment of the present invention
  • FIG. 4 is a block diagram illustrating an example of an encoding device or a decoding device
  • FIG. 5 is a block diagram illustrating an example of another encoding device or decoding device
  • Figure 6 shows an example of a YUV format sampling grid
  • FIG. 8 shows a combination of a quadtree and a binary tree
  • FIG. 9 shows a method flowchart of Embodiment 1 of the present invention.
  • FIG. 10 shows a flowchart of step 906 of the first embodiment of the present invention
  • FIG. 11 shows a flowchart of a method according to a third embodiment of the present invention.
  • Video coding generally refers to processing a sequence of pictures that form a video or a video sequence.
  • picture In the field of video coding, the terms “picture”, “frame” or “image” can be used as synonyms.
  • Video encoding used in this application means video encoding or video decoding.
  • Video encoding is performed on the source side and typically involves processing (e.g., by compressing) the original video picture to reduce the amount of data required to represent the video picture, thereby storing and / or transmitting more efficiently.
  • Video decoding is performed on the destination side and usually involves inverse processing relative to the encoder to reconstruct the video picture.
  • the video picture “encoding” involved in the embodiment should be understood as the “encoding” or “decoding” of the video sequence.
  • the combination of the encoding part and the decoding part is also called codec (encoding and decoding).
  • Each picture of a video sequence is usually partitioned into a set of non-overlapping blocks, usually encoded at the block level.
  • the encoder side usually processes at the block (also called image block, or video block) level, that is, encodes the video.
  • the prediction block is generated by spatial (intra-picture) prediction and temporal (inter-picture) prediction.
  • the current block (currently processed or block to be processed) is subtracted from the prediction block to obtain the residual block, the residual block is transformed in the transform domain and the residual block is quantized to reduce the amount of data to be transmitted (compressed), and the decoder side will
  • the inverse processing part relative to the encoder is applied to the encoded or compressed block to reconstruct the current block for representation.
  • the encoder duplicates the decoder processing loop so that the encoder and decoder generate the same predictions (such as intra prediction and inter prediction) and / or reconstruction for processing, that is, encoding subsequent blocks.
  • block may be part of a picture or frame. This application defines the following key terms:
  • Current block Refers to the block currently being processed. For example, in encoding, it means the block that is currently being encoded; in decoding, it means the block that is currently being decoded. If the currently processed block is a chroma component block, it is called the current chroma block.
  • the luma block corresponding to the current chroma block may be referred to as the current luma block.
  • CTU coding tree unit (coding tree unit).
  • An image is composed of multiple CTUs.
  • a CTU usually corresponds to a square image area, which contains the luma pixels and chroma pixels in this image area (or it can only include luma pixels). (Or may also include only chroma pixels); the CTU also contains syntax elements, which indicate how to divide the CTU into at least one coding unit (coding unit, CU), and a method of decoding each coding unit to obtain a reconstructed image.
  • CU coding unit, usually corresponding to a rectangular area of A ⁇ B, including A ⁇ B luminance pixels and its corresponding chroma pixels, A is the width of the rectangle, B is the height of the rectangle, A and B can be the same or different
  • the value of A and B is usually an integer power of two, for example, 256, 128, 64, 32, 16, 8, and 4.
  • a coding unit can be decoded to obtain a reconstructed image of an A ⁇ B rectangular area.
  • the decoding process usually includes prediction, inverse quantization, and inverse transformation to generate predicted images and residuals. The predicted images and residuals are superimposed and reconstructed image.
  • Embodiments of the encoder 20, the decoder 30, and the encoding system 10 are described below based on FIGS. 1A, 1B, and 3.
  • FIG. 1A is a conceptual or schematic block diagram illustrating an exemplary encoding system 10.
  • a video encoding system 10 that can use the technology of the present application (the present disclosure).
  • the encoder 20 (eg, video encoder 20) and decoder 30 (eg, video decoder 30) of the video encoding system 10 represent device instances that can be used to perform intra prediction according to various examples described in this application.
  • the encoding system 10 includes a source device 12 for providing the encoded data 13, such as the encoded picture 13, to a destination device 14 that decodes the encoded data 13, for example.
  • the source device 12 includes an encoder 20, and may optionally include a picture source 16, such as a pre-processing unit 18 of a picture pre-processing unit 18, and a communication interface or communication unit 22.
  • a picture source 16 such as a pre-processing unit 18 of a picture pre-processing unit 18, and a communication interface or communication unit 22.
  • the picture source 16 may include or may be any kind of picture capture device for, for example, capturing real-world pictures, and / or any kind of pictures or comments (for screen content encoding, some text on the screen is also considered to be a picture to be encoded Or a part of an image) generating device, for example, a computer graphics processor for generating computer animated pictures, or for obtaining and / or providing real world pictures, computer animated pictures (for example, screen content, virtual reality (VR) ) Pictures) of any type of device, and / or any combination thereof (eg, augmented reality (AR) pictures).
  • a computer graphics processor for generating computer animated pictures, or for obtaining and / or providing real world pictures, computer animated pictures (for example, screen content, virtual reality (VR) ) Pictures) of any type of device, and / or any combination thereof (eg, augmented reality (AR) pictures).
  • AR augmented reality
  • Pictures can be viewed as a two-dimensional array or matrix of sample points with luminance values.
  • the sampling points in the array may also be called pixels (short for picture element) or pixels.
  • the number of sampling points of the array or picture in the horizontal and vertical directions (or axes) defines the size and / or resolution of the picture.
  • three color components are usually used, that is, a picture can be represented as or contain three sampling arrays.
  • pictures include corresponding red, green, and blue sampling arrays.
  • each pixel is usually represented in a luma / chroma format or color space, for example, YCbCr, including the luma component indicated by Y (sometimes also indicated by L) and the two chroma indicated by Cb and Cr Weight.
  • Luma (abbreviated as luma) component Y represents luminance or gray level intensity (for example, both are the same in a grayscale picture), while two chroma (abbreviated as chroma) components Cb and Cr represent chroma or color information components .
  • a picture in the YCbCr format includes a luminance sampling array of luminance sampling values (Y), and two chrominance sampling arrays of chrominance values (Cb and Cr).
  • Y luminance sampling values
  • Cb and Cr chrominance sampling arrays of chrominance values
  • Pictures in RGB format can be converted or converted to YCbCr format, and vice versa. This process is also called color conversion or conversion. If the picture is black, the picture can only include an array of luminance samples.
  • the picture source 16 may be, for example, a camera for capturing pictures, such as a memory of a picture memory, including or storing a previously captured or generated picture, and / or any category (internal) of obtaining or receiving a picture Or external) interface.
  • the camera may be, for example, an integrated camera that is local or integrated in the source device, and the memory may be local or, for example, an integrated memory that is integrated in the source device.
  • the interface may be, for example, an external interface for receiving pictures from an external video source.
  • the external video source is, for example, an external picture capture device, such as a camera, an external memory, or an external picture generation device.
  • the external picture generation device is, for example, an external computer graphics processor, a computer.
  • the interface may be any type of interface according to any proprietary or standardized interface protocol, such as a wired or wireless interface, an optical interface.
  • the interface for acquiring the picture data 17 may be the same interface as the communication interface 22 or a part of the communication interface 22.
  • a picture or picture data 17 (for example, video data 16) may also be referred to as an original picture or original picture data 17.
  • the pre-processing unit 18 is configured to receive (original) picture data 17 and perform pre-processing on the picture data 17 to obtain pre-processed pictures 19 or pre-processed picture data 19.
  • the pre-processing performed by the pre-processing unit 18 may include trimming, color format conversion (for example, conversion from RGB to YCbCr), color correction, or denoising. It is understood that the pre-processing unit 18 may be an optional component.
  • An encoder 20 (e.g., video encoder 20) is used to receive the pre-processed picture data 19 and provide the encoded picture data 21 (details will be further described below, for example, based on Fig. 2 or Fig. 4). In one example, the encoder 20 may be used to perform the first to third embodiments described below.
  • the communication interface 22 of the source device 12 can be used to receive the encoded picture data 21 and transmit it to other devices, such as the destination device 14 or any other device, for storage or direct reconstruction, or for correspondingly storing the
  • the encoded data 13 and / or the encoded picture data 21 are processed before transmitting the encoded data 13 to other devices, such as the destination device 14 or any other device for decoding or storage.
  • the destination device 14 includes a decoder 30 (for example, a video decoder 30), and in addition, optionally, it may include a communication interface or communication unit 28, a post-processing unit 32, and a display device 34.
  • a decoder 30 for example, a video decoder 30
  • the communication interface 28 of the destination device 14 is used, for example, to receive the encoded picture data 21 or the encoded data 13 directly from the source device 12 or any other source.
  • Any other source is, for example, a storage device, and the storage device is, for example, encoded picture data storage. device.
  • the communication interface 22 and the communication interface 28 can be used for direct communication through a direct communication link between the source device 12 and the destination device 14 or transmission or reception of encoded picture data 21 or encoded data 13 through any type of network
  • the link is, for example, a direct wired or wireless connection, and any type of network is, for example, a wired or wireless network or any combination thereof, or any type of private and public network, or any combination thereof.
  • the communication interface 22 may be used, for example, to encapsulate the encoded picture data 21 into a suitable format, such as a packet, for transmission over a communication link or communication network.
  • the communication interface 28 forming a corresponding part of the communication interface 22 may be used, for example, to decapsulate the encoded data 13 to obtain the encoded picture data 21.
  • Both the communication interface 22 and the communication interface 28 may be configured as unidirectional communication interfaces, as indicated by the arrows for the encoded picture data 13 from the source device 12 to the destination device 14 in FIG. 1A, or configured as bidirectional communication interfaces, and It can be used, for example, to send and receive messages to establish a connection, acknowledge, and exchange any other information related to a communication link and / or data transmission such as encoded picture data transmission.
  • the decoder 30 is configured to receive the encoded picture data 21 and provide the decoded picture data 31 or the decoded picture 31 (details will be further described below, for example, based on FIG. 3 or FIG. 5). In one example, the decoder 30 may be used to perform the first to third embodiments described below.
  • the post-processor 32 of the destination device 14 is used to post-process decoded picture data 31 (also referred to as reconstructed picture data), for example, decoded picture 131 to obtain post-processed picture data 33, for example, post-processed Picture 33.
  • the post-processing performed by the post-processing unit 32 may include, for example, color format conversion (e.g., conversion from YCbCr to RGB), color correction, retouching, or resampling, or any other processing, such as preparing the decoded picture data 31 to be processed by
  • the display device 34 displays it.
  • the display device 34 of the destination device 14 is used to receive the post-processed picture data 33 to display a picture to, for example, a user or a viewer.
  • the display device 34 may be or may include any kind of display for presenting a reconstructed picture, such as an integrated or external display or monitor.
  • the display may include a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (LCoS), Digital light processor (DLP) or any other display of any kind.
  • FIG. 1A illustrates the source device 12 and the destination device 14 as separate devices
  • the device embodiment may also include the source device 12 and the destination device 14 or both of the functionality, that is, the source device 12 or corresponding And the functionality of the destination device 14 or equivalent.
  • the same hardware and / or software, or separate hardware and / or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .
  • Both the encoder 20 e.g., video encoder 20
  • decoder 30 e.g., video decoder 30
  • DSP digital signal processors
  • ASIC application-specific integrated circuit
  • FPGA field-programmable gate array
  • the device may store the software's instructions in a suitable non-transitory computer-readable storage medium, and may use one or more processors to execute the instructions in hardware to perform the techniques of the present disclosure.
  • processors any one of the foregoing (including hardware, software, a combination of hardware and software, etc.) can be considered as one or more processors.
  • Each of the video encoder 20 and the video decoder 30 may be included in one or more encoders or decoders, and any of the encoders or decoders may be integrated as a combined encoder / decoder in a corresponding device (Codec).
  • the source device 12 may be referred to as a video encoding device or a video encoding device.
  • the destination device 14 may be referred to as a video decoding device or a video decoding device.
  • the source device 12 and the destination device 14 may be examples of a video encoding device or a video encoding apparatus.
  • Source device 12 and destination device 14 may include any of a variety of devices, including any type of handheld or stationary device, such as a notebook or laptop computer, mobile phone, smartphone, tablet or tablet computer, video camera, desktop Computer, set-top box, TV, display device, digital media player, video game console, video streaming device (such as content service server or content distribution server), broadcast receiver device, broadcast transmitter device, etc., and may not be used Or use any kind of operating system.
  • a notebook or laptop computer mobile phone, smartphone, tablet or tablet computer, video camera, desktop Computer, set-top box, TV, display device, digital media player, video game console, video streaming device (such as content service server or content distribution server), broadcast receiver device, broadcast transmitter device, etc., and may not be used Or use any kind of operating system.
  • source device 12 and destination device 14 may be equipped for wireless communication. Therefore, the source device 12 and the destination device 14 may be wireless communication devices.
  • the video encoding system 10 shown in FIG. 1A is merely an example, and the techniques of this application may be applicable to video encoding settings (eg, video encoding or video decoding) that do not necessarily include any data communication between encoding and decoding devices.
  • data may be retrieved from local storage, streamed over a network, and the like.
  • the video encoding device may encode the data and store the data to a memory, and / or the video decoding device may retrieve the data from the memory and decode the data.
  • encoding and decoding are performed by devices that do not communicate with each other, but only encode data to and / or retrieve data from memory and decode data.
  • video decoder 30 may be used to perform the reverse process.
  • video decoder 30 may be used to receive and parse such syntax elements, and decode related video data accordingly.
  • video encoder 20 may entropy encode syntax elements into an encoded video bitstream.
  • video decoder 30 may parse such syntax elements and decode related video data accordingly.
  • FIG. 1B is an explanatory diagram of an example of a video encoding system 40 including the encoder 20 of FIG. 2 and / or the decoder 30 of FIG. 3 according to an exemplary embodiment.
  • the system 40 may implement a combination of various techniques of the present application.
  • the video encoding system 40 may include an imaging device 41, a video encoder 20, a video decoder 30 (and / or a video encoder implemented by the logic circuit 47 of the processing unit 46), an antenna 42, One or more processors 43, one or more memories 44, and / or a display device 45.
  • the imaging device 41, antenna 42, processing unit 46, logic circuit 47, video encoder 20, video decoder 30, processor 43, memory 44, and / or display device 45 can communicate with each other.
  • video encoding system 40 is shown with video encoder 20 and video decoder 30, in different examples, video encoding system 40 may include only video encoder 20 or only video decoder 30.
  • the video encoding system 40 may include an antenna 42.
  • the antenna 42 may be used to transmit or receive an encoded bit stream of video data.
  • the video encoding system 40 may include a display device 45.
  • the display device 45 may be used to present video data.
  • the logic circuit 47 may be implemented by the processing unit 46.
  • the processing unit 46 may include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like.
  • the video encoding system 40 may also include an optional processor 43, which may similarly include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like.
  • ASIC application-specific integrated circuit
  • the logic circuit 47 may be implemented by hardware, such as dedicated hardware for video encoding, and the processor 43 may be implemented by general software, operating system, and the like.
  • the memory 44 may be any type of memory, such as volatile memory (e.g., Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), etc.) or non-volatile memory Memory (for example, flash memory, etc.).
  • the memory 44 may be implemented by a cache memory.
  • the logic circuit 47 may access the memory 44 (eg, for implementing an image buffer).
  • the logic circuit 47 and / or the processing unit 46 may include a memory (eg, a cache, etc.) for implementing an image buffer or the like.
  • video encoder 20 implemented by logic circuits may include an image buffer (eg, implemented by processing unit 46 or memory 44) and a graphics processing unit (eg, implemented by processing unit 46).
  • the graphics processing unit may be communicatively coupled to the image buffer.
  • the graphics processing unit may include a video encoder 20 implemented by a logic circuit 47 to implement the various modules discussed with reference to FIG. 2 and / or any other encoder system or subsystem described herein.
  • Logic circuits can be used to perform various operations discussed herein.
  • Video decoder 30 may be implemented in a similar manner by logic circuit 47 to implement the various modules discussed with reference to decoder 30 of FIG. 3 and / or any other decoder system or subsystem described herein.
  • video decoder 30 implemented by a logic circuit may include an image buffer (implemented by processing unit 2820 or memory 44) and a graphics processing unit (eg, implemented by processing unit 46).
  • the graphics processing unit may be communicatively coupled to the image buffer.
  • the graphics processing unit may include a video decoder 30 implemented by a logic circuit 47 to implement various modules discussed with reference to FIG. 3 and / or any other decoder system or subsystem described herein.
  • the antenna 42 of the video encoding system 40 may be used to receive an encoded bit stream of video data.
  • the encoded bitstream may contain data, indicators, index values, mode selection data, etc. related to encoded video frames discussed herein, such as data related to coded segmentation (e.g., transform coefficients or quantized transform coefficients , (As discussed) optional indicators, and / or data defining code partitions).
  • the video encoding system 40 may also include a video decoder 30 coupled to the antenna 42 and used to decode the encoded bitstream.
  • the display device 45 is used to present video frames.
  • FIG. 2 shows a schematic / conceptual block diagram of an example of a video encoder 20 for implementing the technology of the present (disclosed) application.
  • the video encoder 20 includes a residual calculation unit 204, a transformation processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transformation processing unit 212, a reconstruction unit 214, a buffer 216, and a loop filter.
  • the prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262.
  • the inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown).
  • the video encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder according to a hybrid video codec.
  • the residual calculation unit 204, the transformation processing unit 206, the quantization unit 208, the prediction processing unit 260, and the entropy encoding unit 270 form the forward signal path of the encoder 20, while the inverse quantization unit 210, the inverse transformation processing unit 212,
  • the constructing unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (DPB) 230, and the prediction processing unit 260 form a backward signal path of the encoder, wherein the backward signal path of the encoder corresponds to To the decoder's signal path (see decoder 30 in Figure 3).
  • the encoder 20 receives a picture 201 or a block 203 of the picture 201 through, for example, an input 202, for example, a picture in a picture sequence forming a video or a video sequence.
  • the picture block 203 can also be called the current picture block or the picture block to be encoded
  • the picture 201 can be called the current picture or the picture to be encoded (especially when the current picture is distinguished from other pictures in video encoding, other pictures such as the same video sequence (Ie previously encoded and / or decoded pictures in the video sequence of the current picture).
  • An embodiment of the encoder 20 may include a segmentation unit (not shown in FIG. 2) for segmenting the picture 201 into multiple blocks, such as the block 203, and generally into multiple non-overlapping blocks.
  • the segmentation unit can be used to use the same block size and corresponding raster to define the block size for all pictures in the video sequence, or to change the block size between pictures or subsets or groups of pictures, and split each picture into Corresponding block.
  • the prediction processing unit 260 of the video encoder 20 may be used to perform any combination of the aforementioned segmentation techniques.
  • block 203 is also or can be regarded as a two-dimensional array or matrix of sampling points with brightness values (sampling values), although its size is smaller than picture 201.
  • block 203 may include, for example, one sampling array (e.g., a luminance array in the case of a black and white picture 201) or three sampling arrays (e.g., one luminance array and two chroma arrays in the case of a color picture) or An array of any other number and / or category of color formats applied.
  • the number of sampling points in the horizontal and vertical directions (or axes) of the block 203 defines the size of the block 203.
  • the encoder 20 shown in FIG. 2 is used to encode a picture 201 block by block, for example, performing encoding and prediction on each block 203.
  • the residual calculation unit 204 is configured to calculate the residual block 205 based on the picture block 203 and the prediction block 265 (the other details of the prediction block 265 are provided below). For example, the sample value of the picture block 203 is subtracted from the prediction by sample-by-sample (pixel-by-pixel). Sample values of block 265 to obtain residual block 205 in the sample domain.
  • the transform processing unit 206 is configured to apply a transform such as discrete cosine transform (DCT) or discrete sine transform (DST) on the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain.
  • a transform such as discrete cosine transform (DCT) or discrete sine transform (DST)
  • DCT discrete cosine transform
  • DST discrete sine transform
  • the transform coefficient 207 may also be referred to as a transform residual coefficient, and represents a residual block 205 in a transform domain.
  • the transform processing unit 206 may be used to apply an integer approximation of DCT / DST, such as the transform specified for HEVC / H.265. Compared to an orthogonal DCT transform, this integer approximation is usually scaled by a factor. To maintain the norm of the residual blocks processed by the forward and inverse transforms, an additional scaling factor is applied as part of the transform process.
  • the scaling factor is usually selected based on certain constraints, for example, the scaling factor is a power of two used for shift operations, the bit depth of the transform coefficients, the trade-off between accuracy, and implementation cost.
  • a specific scaling factor is specified on the decoder 30 side by, for example, the inverse transform processing unit 212 (and on the encoder 20 side by, for example, the inverse transform processing unit 212 as the corresponding inverse transform), and accordingly, the The 20 side specifies a corresponding scaling factor for the positive transformation through the transformation processing unit 206.
  • the quantization unit 208 is used to quantize the transform coefficient 207, for example, by applying scalar quantization or vector quantization to obtain the quantized transform coefficient 209.
  • the quantized transform coefficient 209 may also be referred to as a quantized residual coefficient 209.
  • the quantization process can reduce the bit depth associated with some or all of the transform coefficients 207. For example, n-bit transform coefficients may be rounded down to m-bit transform coefficients during quantization, where n is greater than m.
  • the degree of quantization can be modified by adjusting the quantization parameter (QP). For scalar quantization, for example, different scales can be applied to achieve finer or coarser quantization.
  • a smaller quantization step size corresponds to a finer quantization, while a larger quantization step size corresponds to a coarser quantization.
  • An appropriate quantization step size can be indicated by a quantization parameter (QP).
  • the quantization parameter may be an index of a predefined set of suitable quantization steps.
  • smaller quantization parameters may correspond to fine quantization (smaller quantization step size)
  • larger quantization parameters may correspond to coarse quantization (larger quantization step size)
  • Quantization may include division by a quantization step size and corresponding quantization or inverse quantization performed, for example, by inverse quantization 210, or may include multiplication by a quantization step size.
  • Embodiments according to some standards such as HEVC may use quantization parameters to determine the quantization step size.
  • the quantization step size can be calculated using a fixed-point approximation using an equation containing division based on the quantization parameter. Additional scaling factors may be introduced for quantization and inverse quantization to restore the norm of the residual block that may be modified due to the scale used in the fixed-point approximation of the equation for the quantization step size and quantization parameter.
  • inverse transform and inverse quantization scales can be combined.
  • a custom quantization table can be used and signaled from the encoder to the decoder in, for example, a bitstream. Quantization is a lossy operation, where the larger the quantization step, the greater the loss.
  • the inverse quantization unit 210 is configured to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain the inverse quantized coefficients 211. For example, based on or using the same quantization step as the quantization unit 208, the quantization scheme applied by the quantization unit 208 is applied. Inverse quantization scheme.
  • the dequantized coefficient 211 may also be referred to as a dequantized residual coefficient 211, which corresponds to the transform coefficient 207, although the loss due to quantization is usually different from the transform coefficient.
  • the inverse transform processing unit 212 is used to apply an inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST), in the sample domain.
  • DCT inverse discrete cosine transform
  • DST inverse discrete sine transform
  • the inverse transform block 213 may also be referred to as an inverse transform inverse quantized block 213 or an inverse transform residual block 213.
  • the reconstruction unit 214 (for example, the summer 214) is used to add the inverse transform block 213 (that is, the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain.
  • the sample values of the reconstructed residual block 213 are added to the sample values of the prediction block 265.
  • a buffer unit 216 (or simply "buffer" 216), such as a line buffer 216, is used to buffer or store the reconstructed block 215 and corresponding sample values, for example, for intra prediction.
  • the encoder may be used to use any unfiltered reconstructed block and / or corresponding sample values stored in the buffer unit 216 for any category of estimation and / or prediction, such as intra-frame prediction.
  • an embodiment of the encoder 20 may be configured such that the buffer unit 216 is used not only for storing the reconstructed block 215 for intra prediction 254, but also for the loop filter unit 220 (not shown in FIG. 2). Out), and / or, for example, to make the buffer unit 216 and the decoded picture buffer unit 230 form a buffer.
  • Other embodiments may be used to use the filtered block 221 and / or blocks or samples from the decoded picture buffer 230 (neither of which are shown in FIG. 2) as an input or basis for intra prediction 254.
  • the loop filter unit 220 (or simply "loop filter” 220) is configured to filter the reconstructed block 215 to obtain the filtered block 221, so as to smoothly perform pixel conversion or improve video quality.
  • the loop filter unit 220 is intended to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters, such as a bilateral filter, Adaptive loop filters (adaptive loop filters, ALF), or sharpening or smoothing filters, or cooperative filters.
  • the loop filter unit 220 is shown as an in-loop filter in FIG. 2, in other configurations, the loop filter unit 220 may be implemented as a post-loop filter.
  • the filtered block 221 may also be referred to as a filtered reconstructed block 221.
  • the decoded picture buffer 230 may store the reconstructed encoded block after the loop filter unit 220 performs a filtering operation on the reconstructed encoded block.
  • An embodiment of the encoder 20 may be used to output loop filter parameters (e.g., sample adaptive offset information), for example, directly output or by the entropy coding unit 270 or any other
  • the entropy coding unit outputs after entropy coding, for example, so that the decoder 30 can receive and apply the same loop filter parameters for decoding.
  • the decoded picture buffer (DPB) 230 may be a reference picture memory that stores reference picture data for the video encoder 20 to encode video data.
  • DPB 230 can be formed by any of a variety of memory devices, such as dynamic random access (DRAM) (including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), and resistive RAM (resistive RAM, RRAM)) or other types of memory devices.
  • DRAM dynamic random access
  • SDRAM synchronous DRAM
  • MRAM magnetoresistive RAM
  • RRAM resistive RAM
  • the DPB 230 and the buffer 216 may be provided by the same memory device or separate memory devices.
  • a decoded picture buffer (DPB) 230 is used to store the filtered block 221.
  • the decoded picture buffer 230 may be further used to store other previous filtered blocks of the same current picture or different pictures such as previously reconstructed pictures, such as the previously reconstructed and filtered block 221, and may provide a complete previous Reconstruction is the decoded picture (and corresponding reference blocks and samples) and / or part of the reconstructed current picture (and corresponding reference blocks and samples), for example for inter prediction.
  • a decoded picture buffer (DPB) 230 is used to store the reconstructed block 215.
  • Prediction processing unit 260 also referred to as block prediction processing unit 260, is used to receive or obtain block 203 (current block 203 of current picture 201) and reconstructed picture data, such as a reference to the same (current) picture from buffer 216 Samples and / or reference picture data 231 from one or more previously decoded pictures from the decoded picture buffer 230, and used to process such data for prediction, i.e., may be provided as inter-predicted blocks 245 or intra- Prediction block 265 of prediction block 255.
  • the mode selection unit 262 may be used to select a prediction mode (such as an intra or inter prediction mode) and / or a corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.
  • a prediction mode such as an intra or inter prediction mode
  • a corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.
  • An embodiment of the mode selection unit 262 may be used to select a prediction mode (e.g., selected from those prediction modes supported by the prediction processing unit 260) that provides the best match or minimum residual (minimum residual means Better compression in transmission or storage), or provide minimal signaling overhead (minimum signaling overhead means better compression in transmission or storage), or consider or balance both.
  • the mode selection unit 262 may be used to determine a prediction mode based on rate distortion optimization (RDO), that is, to select a prediction mode that provides the minimum code rate distortion optimization, or to select a prediction mode whose related code rate distortion meets at least the prediction mode selection criteria. .
  • RDO rate distortion optimization
  • the encoder 20 is used to determine or select the best or optimal prediction mode from a set of (predetermined) prediction modes.
  • the prediction mode set may include, for example, an intra prediction mode and / or an inter prediction mode.
  • the intra prediction mode set may include 35 different intra prediction modes, or may include 67 different intra prediction modes, or may include intra prediction modes defined in the developing H.266.
  • the set of inter-prediction modes depends on the available reference pictures (i.e., at least part of the decoded pictures previously stored in DBP 230) and other inter-prediction parameters, such as whether to use the entire reference picture or only a part of the reference picture, A search window area around the area of the current block, for example, is used to search for the best matching reference block, and / or for example, depending on whether pixel interpolation such as half-pixel and / or quarter-pixel interpolation is applied.
  • a skip mode and / or a direct mode can also be applied.
  • the prediction processing unit 260 may be further configured to divide the block 203 into smaller block partitions or sub-blocks, for example, using a quad-tree (QT) partition, a binary-tree (BT) partition, or Triple-tree (TT) segmentation, or any combination thereof, and for performing predictions, for example, for each of block partitions or sub-blocks, where the mode selection includes selecting the tree structure of the partitioned block 203 and the selection applied to the block The prediction mode for each of the partitions or sub-blocks.
  • QT quad-tree
  • BT binary-tree
  • TT Triple-tree
  • the inter prediction unit 244 may include a motion estimation (ME) unit (not shown in FIG. 2) and a motion compensation (MC) unit (not shown in FIG. 2).
  • the motion estimation unit is configured to receive or obtain picture block 203 (current picture block 203 of current picture 201) and decoded picture 231, or at least one or more previously reconstructed blocks, for example, one or more other / different previous
  • the reconstructed block of picture 231 is decoded for motion estimation.
  • the video sequence may include the current picture and the previously decoded picture 31, or in other words, the current picture and the previously decoded picture 31 may be part of the picture sequence forming the video sequence or form the picture sequence.
  • the encoder 20 may be used to select a reference block from multiple reference blocks of the same or different pictures in multiple other pictures, and provide a reference picture and / or a reference to a motion estimation unit (not shown in FIG. 2).
  • the offset (spatial offset) between the position of the block (X, Y coordinates) and the position of the current block is used as an inter prediction parameter. This offset is also called a motion vector (MV).
  • the motion compensation unit is used for obtaining, for example, receiving inter prediction parameters, and performing inter prediction based on or using the inter prediction parameters to obtain the inter prediction block 245.
  • Motion compensation performed by a motion compensation unit may include taking out or generating a prediction block based on a motion / block vector determined through motion estimation (possibly performing interpolation on sub-pixel accuracy). Interpolation filtering can generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks that can be used to encode picture blocks.
  • the motion compensation unit 246 may locate the prediction block pointed to by the motion vector in a reference picture list.
  • Motion compensation unit 246 may also generate syntax elements associated with blocks and video slices for use by video decoder 30 when decoding picture blocks of video slices.
  • the intra prediction unit 254 is configured to obtain, for example, a picture block 203 (current picture block) and one or more previously reconstructed blocks, such as reconstructed neighboring blocks, that receive the same picture for intra estimation.
  • the encoder 20 may be used to select an intra prediction mode from a plurality of intra prediction modes.
  • Embodiments of the encoder 20 may be used to select an intra-prediction mode based on an optimization criterion, such as based on a minimum residual (eg, an intra-prediction mode that provides a prediction block 255 most similar to the current picture block 203) or a minimum code rate distortion.
  • an optimization criterion such as based on a minimum residual (eg, an intra-prediction mode that provides a prediction block 255 most similar to the current picture block 203) or a minimum code rate distortion.
  • the intra prediction unit 254 is further configured to determine the intra prediction block 255 based on the intra prediction parameters of the intra prediction mode as selected. In any case, after selecting the intra prediction mode for the block, the intra prediction unit 254 is further configured to provide the intra prediction parameters to the entropy encoding unit 270, that is, to provide an indication of the selected intra prediction mode for the block. Information. In one example, the intra prediction unit 254 may be used to perform any combination of intra prediction techniques described below.
  • the entropy coding unit 270 is configured to apply an entropy coding algorithm or scheme (for example, a variable length coding (VLC) scheme, a context adaptive VLC (context adaptive VLC, CAVLC) scheme, an arithmetic coding scheme, and a context adaptive binary arithmetic Coding (context, adaptive binary coding, CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or other entropy Encoding method or technique) applied to one or all of the quantized residual coefficients 209, inter prediction parameters, intra prediction parameters, and / or loop filter parameters (or not applied) to obtain
  • VLC variable length coding
  • CAVLC context adaptive VLC
  • CABAC syntax-based context-adaptive binary arithmetic coding
  • PIPE probability interval partitioning entropy
  • the encoded picture data 21 is output in the form of, for example, an encoded bit stream 21.
  • the encoded bitstream may be transmitted to video decoder 30 or archived for later transmission or retrieval by video decoder 30.
  • the entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice that is being encoded.
  • video encoder 20 may be used to encode a video stream.
  • the non-transform-based encoder 20 may directly quantize the residual signal without a transform processing unit 206 for certain blocks or frames.
  • the encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined into a single unit.
  • FIG. 3 illustrates an exemplary video decoder 30 for implementing the techniques of the present application.
  • the video decoder 30 is configured to receive, for example, encoded picture data (eg, an encoded bit stream) 21 encoded by the encoder 20 to obtain a decoded picture 231.
  • video decoder 30 receives video data from video encoder 20, such as an encoded video bitstream and associated syntax elements representing picture blocks of encoded video slices.
  • the decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (such as a summer 314), a buffer 316, a loop filter 320, The decoded picture buffer 330 and the prediction processing unit 360.
  • the prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362.
  • video decoder 30 may perform a decoding pass that is substantially inverse to the encoding pass described with reference to video encoder 20 of FIG. 2.
  • the entropy decoding unit 304 is configured to perform entropy decoding on the encoded picture data 21 to obtain, for example, quantized coefficients 309 and / or decoded encoding parameters (not shown in FIG. 3), for example, inter prediction, intra prediction parameters , (Filtered) any or all of the loop filter parameters and / or other syntax elements.
  • the entropy decoding unit 304 is further configured to forward the inter prediction parameters, the intra prediction parameters, and / or other syntax elements to the prediction processing unit 360.
  • Video decoder 30 may receive syntax elements at the video slice level and / or the video block level.
  • the inverse quantization unit 310 may be functionally the same as the inverse quantization unit 110
  • the inverse transformation processing unit 312 may be functionally the same as the inverse transformation processing unit 212
  • the reconstruction unit 314 may be functionally the same as the reconstruction unit 214
  • the buffer 316 may be functionally
  • the loop filter 320 may be functionally the same as the loop filter 220
  • the decoded picture buffer 330 may be functionally the same as the decoded picture buffer 230.
  • the prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354.
  • the inter prediction unit 344 may be functionally similar to the inter prediction unit 244 and the intra prediction unit 354 may be functionally similar to the intra prediction unit 254.
  • the prediction processing unit 360 is generally used to perform block prediction and / or obtain a prediction block 365 from the encoded data 21, and to receive or obtain prediction-related parameters from, for example, an entropy decoding unit 304 (explicitly or implicitly) and / or Information about the selected prediction mode.
  • the intra-prediction unit 354 of the prediction processing unit 360 is used for the intra-prediction mode based on the signal representation and the previously decoded block from the current frame or picture Data to generate a prediction block 365 for a picture block of the current video slice.
  • the inter-prediction unit 344 e.g., a motion compensation unit
  • the other syntax elements generate a prediction block 365 for a video block of the current video slice.
  • a prediction block may be generated from a reference picture in a reference picture list.
  • the video decoder 30 may construct a reference frame list using a default construction technique based on the reference pictures stored in the DPB 330: List 0 and List 1.
  • the prediction processing unit 360 is configured to determine prediction information for a video block of a current video slice by analyzing a motion vector and other syntax elements, and use the prediction information to generate a prediction block for a current video block that is being decoded. For example, the prediction processing unit 360 uses some of the received syntax elements to determine a prediction mode (e.g., intra or inter prediction) of a video block used to encode a video slice, an inter prediction slice type (e.g., B slice, P slice or GPB slice), construction information for one or more of the reference picture lists for the slice, motion vectors for each inter-coded video block for the slice, each warp for the slice The inter-prediction status and other information of the inter-coded video block to decode the video block of the current video slice.
  • a prediction mode e.g., intra or inter prediction
  • an inter prediction slice type e.g., B slice, P slice or GPB slice
  • construction information for one or more of the reference picture lists for the slice motion vectors for each inter-coded video block
  • the inverse quantization unit 310 may be used for inverse quantization (ie, inverse quantization) of the quantized transform coefficients provided in the bitstream and decoded by the entropy decoding unit 304.
  • the inverse quantization process may include using the quantization parameters calculated by video encoder 20 for each video block in the video slice to determine the degree of quantization that should be applied and also to determine the degree of inverse quantization that should be applied.
  • the inverse transform processing unit 312 is configured to apply an inverse transform (for example, an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process) to the transform coefficients to generate a residual block in the pixel domain.
  • an inverse transform for example, an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process
  • Reconstruction unit 314 (e.g., summer 314) is used to add inverse transform block 313 (i.e., reconstructed residual block 313) to prediction block 365 to obtain reconstructed block 315 in the sample domain, such as by The sample values of the reconstructed residual block 313 are added to the sample values of the prediction block 365.
  • the loop filter unit 320 (during or after the encoding cycle) is used to filter the reconstructed block 315 to obtain the filtered block 321 so as to smoothly perform pixel conversion or improve video quality.
  • the loop filter unit 320 may be used to perform any combination of filtering techniques described below.
  • the loop filter unit 320 is intended to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters such as a bilateral filter, Adaptive loop filters (adaptive loop filters, ALF), or sharpening or smoothing filters, or cooperative filters.
  • the loop filter unit 320 is shown as an in-loop filter in FIG. 3, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.
  • the decoded video block 321 in a given frame or picture is then stored in a decoded picture buffer 330 that stores reference pictures for subsequent motion compensation.
  • the decoder 30 is used, for example, to output a decoded picture 31 through an output 332 for presentation to or review by a user.
  • video decoder 30 may be used to decode the compressed bitstream.
  • the decoder 30 may generate an output video stream without the loop filter unit 320.
  • the non-transform-based decoder 30 may directly inversely quantize the residual signal without the inverse transform processing unit 312 for certain blocks or frames.
  • the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined into a single unit.
  • FIG. 4 is a schematic structural diagram of a video decoding device 400 (such as a video encoding device 400 or a video decoding device 400) according to an embodiment of the present invention.
  • Video coding device 400 is adapted to implement the embodiments described herein.
  • the video coding device 400 may be a video decoder (such as video decoder 30 of FIG. 1A) or a video encoder (such as video encoder 20 of FIG. 1A).
  • the video decoding device 400 may be one or more of the video decoder 30 of FIG. 1A or the video encoder 20 of FIG. 1A described above.
  • the video decoding device 400 includes: an entry port 410 and a receiving unit (Rx) 420 for receiving data, a processor, a logic unit or a central processing unit (CPU) 430 for processing data, and a transmitter unit for transmitting data (Tx) 440 and egress port 450, and a memory 460 for storing data.
  • the video decoding device 400 may further include a photoelectric conversion component and an electro-optic (EO) component coupled with the entrance port 410, the receiver unit 420, the transmitter unit 440, and the exit port 450 for an exit or entrance of an optical signal or an electric signal.
  • EO electro-optic
  • the processor 430 is implemented by hardware and software.
  • the processor 430 may be implemented as one or more CPU chips, cores (eg, multi-core processors), FPGAs, ASICs, and DSPs.
  • the processor 430 communicates with the ingress port 410, the receiver unit 420, the transmitter unit 440, the egress port 450, and the memory 460.
  • the processor 430 includes a decoding module 470 (eg, an encoding module 470 or a decoding module 470).
  • the encoding / decoding module 470 implements the embodiments disclosed above. For example, the encoding / decoding module 470 implements, processes, or provides various encoding operations.
  • the function of the video decoding device 400 is substantially improved through the encoding / decoding module 470, and the transition of the video decoding device 400 to different states is affected.
  • the encoding / decoding module 470 is implemented with instructions stored in the memory 460 and executed by the processor 430.
  • the memory 460 includes one or more magnetic disks, tape drives, and solid-state hard disks, which can be used as overflow data storage devices for storing programs when these programs are selectively executed, and for storing instructions and data read during program execution.
  • the memory 460 may be volatile and / or non-volatile, and may be a read-only memory (ROM), a random access memory (RAM), a random content-addressable memory (TCAM), and / or a static state. Random access memory (SRAM).
  • FIG. 5 is a simplified block diagram of an apparatus 500 that can be used as either or both of the source device 12 and the destination device 14 in FIG. 1A according to an exemplary embodiment.
  • the device 500 may implement the technology of the present application.
  • the device 500 for implementing image division may take the form of a computing system including a plurality of computing devices, or use, for example, a mobile phone, tablet computer, laptop computer, notebook computer, desktop computer, and the like The form of a single computing device.
  • the processor 502 in the apparatus 500 may be a central processing unit.
  • the processor 502 may be any other type of device or multiple devices capable of manipulating or processing information, existing or to be developed in the future.
  • speed and efficiency advantages can be achieved using more than one processor.
  • the memory 504 in the device 500 may be a read-only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device can be used as the memory 504.
  • the memory 504 may include code and data 506 accessed by the processor 502 using the bus 512.
  • the memory 504 may further include an operating system 508 and an application program 510, which contains at least one program that permits the processor 502 to perform the methods described herein.
  • the application program 510 may include applications 1 to N, and applications 1 to N further include a video encoding application that performs the methods described herein.
  • the device 500 may also include additional memory in the form of a slave memory 514, which may be, for example, a memory card for use with a mobile computing device. Because a video communication session may contain a large amount of information, this information may be stored in whole or in part in the slave memory 514 and loaded into the memory 504 for processing as needed.
  • the apparatus 500 may also include one or more output devices, such as a display 518.
  • the display 518 may be a touch-sensitive display combining a display and a touch-sensitive element operable to sense a touch input.
  • the display 518 may be coupled to the processor 502 through a bus 512.
  • other output devices may be provided that allow the user to program or otherwise use the device 500, or provide other output devices as an alternative to the display 518.
  • the display can be implemented in different ways, including through a liquid crystal display (LCD), a cathode-ray tube (CRT) display, a plasma display, or a light emitting diode diode (LED) displays, such as organic LED (OLED) displays.
  • LCD liquid crystal display
  • CTR cathode-ray tube
  • plasma display a plasma display
  • LED light emitting diode diode
  • OLED organic LED
  • the apparatus 500 may further include or be in communication with an image sensing device 520, such as a camera or any other image sensing device 520 that can or will be developed in the future to sense an image, such as An image of a user running the device 500.
  • the image sensing device 520 may be placed directly facing a user of the running apparatus 500.
  • the position and optical axis of the image sensing device 520 may be configured such that its field of view includes an area immediately adjacent to the display 518 and the display 518 is visible from the area.
  • the device 500 may also include or be in communication with a sound sensing device 522, such as a microphone or any other sound sensing device that can or will be developed in the future to sense the sound near the device 500.
  • the sound sensing device 522 may be placed directly facing the user of the operating device 500 and may be used to receive a sound, such as a voice or other sound, emitted by the user when the device 500 is running.
  • the processor 502 and the memory 504 of the apparatus 500 are shown in FIG. 5 as being integrated in a single unit, other configurations may be used.
  • the operation of the processor 502 may be distributed among multiple directly-coupled machines (each machine has one or more processors), or distributed in a local area or other network.
  • the memory 504 may be distributed among multiple machines, such as a network-based memory or a memory among multiple machines running the apparatus 500.
  • the bus 512 of the device 500 may be formed by multiple buses.
  • the slave memory 514 may be directly coupled to other components of the device 500 or may be accessed through a network, and may include a single integrated unit, such as one memory card, or multiple units, such as multiple memory cards. Therefore, the apparatus 500 can be implemented in various configurations.
  • a color video contains a chrominance component (U, V) in addition to a luminance (Y) component. Therefore, in addition to encoding the luminance component, it is also necessary to encode the chrominance component.
  • YUV4 4: 4
  • YUV4: 2: 2 2: 0.
  • FIG. 6 where a cross represents a sampling point of a luminance component, and a circle represents a sampling point of a chrominance component.
  • the video decoder can be used to partition a video block with five different partition types allowed at each depth according to three different partition structures (QT, BT, and TT).
  • the partition types include quad-tree partition (QT partition structure), horizontal binary tree partition (BT partition structure), vertical binary tree partition (BT partition structure), horizontal center-side tri-tree partition (TT partition structure), and vertical center- Side tri-tree partitioning (TT partition structure), as shown in Figures 7A to 7E.
  • Quad-tree (QT) partition The block is further divided into four rectangular blocks of the same size.
  • FIG. 7A illustrates an example of quad-tree partitioning.
  • the CTU partition method based on the quadtree QT uses the CTU as the root node of the quadtree, and recursively divides the CTU into leaf nodes according to the quadtree division method.
  • a node corresponds to an image area. If the node is not divided, the node is called a leaf node, and its corresponding image area forms a CU. If the node is divided, the image area corresponding to the node is divided into four regions of the same size (its length The width and width are each half of the divided area. Each area corresponds to a node.
  • the quad tree level (qtDepth) of the root node is 0, and the quad tree level of the child node is the quad tree level of the parent node +1.
  • the size and shape of a node in this application refers to the size and shape of the image area corresponding to the node, that is, the node is a rectangular area in the image.
  • the nodes obtained after the nodes in the Coding tree are divided can be referred to as the child nodes (child nodes) of the nodes, referred to as child nodes for short.
  • a 64 ⁇ 64 CTU node (the quadtree level is 0)
  • Each of these four 32 ⁇ 32 nodes can choose to continue to divide or not to divide according to its corresponding split_cu_flag; if a 32 ⁇ 32 node continues to divide, four 16 ⁇ 16 nodes (four The level of the fork tree is 2). And so on, until all nodes are no longer divided, such a CTU is divided into a group of CUs.
  • the minimum size of a CU is identified in the SPS.
  • 8 ⁇ 8 is the minimum CU.
  • this node defaults to no longer divide, and it does not need to include its division flag in the code stream.
  • the leaf node When a node is parsed as a leaf node, the leaf node is a CU to further analyze the coding information corresponding to the CU (including the prediction mode and transformation coefficients of the CU, such as the coding_unit () syntax structure in H.266), Then, the CU is subjected to decoding, prediction, inverse quantization, inverse transform, and loop filtering according to the encoded information to generate a reconstructed image corresponding to the CU.
  • the Quad Tree (QT) structure enables the CTU to be divided into a group of CUs of appropriate size according to the local characteristics of the image, for example, the smooth area is divided into larger CUs, and the texture-rich area is divided into smaller CUs.
  • a partitioning method in which a CTU is divided into a group of CUs corresponds to a coding tree.
  • Which coding tree should be used by the CTU is usually determined by the encoder's rate distortion optimization (RDO) technology.
  • the encoder attempts multiple CTU partitions, each of which corresponds to a RD cost.
  • the encoder compares the RD cost of various tried partitions and finds the smallest RD cost partition as the CTU.
  • the optimal division method is used for the actual encoding of the CTU.
  • the various CTU division methods attempted by the encoder must comply with the division rules specified by the decoder, so that these can be correctly identified by the decoder.
  • FIG. 7B is an example of vertical binary tree partitioning.
  • Horizontal binary tree division The block is horizontally divided into two rectangular blocks of the same size.
  • FIG. 7C is an example of horizontal binary tree partitioning.
  • FIG. 7D is an example of vertical center-side tri-tree division.
  • Horizontal center-side tri-tree partition The block is horizontally divided into three rectangular blocks, making the two side blocks the same size, and the size of the center block is the sum of the two side blocks.
  • FIG. 7E is an example of horizontal center-side tri-tree partitioning.
  • FIGS. 7B-7E The specific division method of FIGS. 7B-7E is similar to the description of FIG. 7A, and is not repeated here.
  • the root node of the tree; the nodes on the second-level coding tree can be divided into sub-nodes using one of four division methods: horizontal dichotomy, vertical dichotomy, horizontal third dichotomy, and vertical third dichotomy;
  • Leaf nodes are coding units.
  • the binary tree division and the quadtree division are cascaded, and may be referred to as QTBT division.
  • QTBT division For example, CTU is divided according to QT first, and leaf nodes of QT are allowed to continue to use BT division, as shown in FIG. 8.
  • each end point in the right figure of FIG. 8 represents a node, and a node connects 4 solid lines to represent a quad tree partition, and a node connects 2 dotted lines to represent a binary tree partition.
  • the node obtained after the division can be called a child of the node. Node, referred to as child node.
  • each leaf node represents 1 CU; 1 on the binary tree node represents vertical division, 0 represents horizontal division; a CTU is divided into a to m according to the division on the right.
  • These 13 CUs are shown in the left figure of Figure 8.
  • each CU has a QT level (Quad-tree depth, QT depth) and a BT level (Binary tree depth, BT depth).
  • the QT level represents the QT level of the QT leaf node CU to which the CU belongs, and the BT level represents the CU.
  • the BT level of the BT leaf node for example, in Figure 8, the QT level of a and b is 1, the BT level is 2; the QT level of c, d, and e is 1, and the BT level is 1; the QT level of f, k, and l Is 2, the BT level is 1; the QT level of i and j is 2, the BT level is 0; the QT level of g and h is 2, the BT level is 2; the QT level of m is 1, and the BT level is 0. If the CTU is divided into only one CU, the QT level of this CU is 0 and the BT level is 0.
  • the encoder 20 determines which partition type to use (including no further partitioning) and explicitly or implicitly (e.g., the partition type can be derived from a predetermined rule) signals the determined partition type Send to decoder 30.
  • the encoder 20 may determine the type of partition to be used based on the rate distortion cost of the different block types using the check block.
  • the embodiments of the present application can only divide the luma blocks of the current node, thereby improving the encoding and decoding efficiency, reducing the maximum throughput of the decoder, and facilitating the implementation of the decoder.
  • a node generated by a node using a division method when a node generated by a node using a division method includes a chroma block with a side length of a first threshold (or a chroma block with a side length less than a second threshold), then Luminance blocks included in a node are divided using this division method, while chrominance blocks included in a node are no longer divided. In this way, it is possible to avoid generating a chroma block with a side length of the first threshold (or a side length smaller than the second threshold).
  • the first threshold may be 2 and the second threshold may be 4. The following describes it in detail with reference to the first to third embodiments.
  • the video data format is YUV4: 2: 0 for description.
  • the YUV4: 2: 2 data can be adopted in a similar manner.
  • Intra-block copy (IBC) coding tool is adopted in the extended standard SVC of HEVC, which is mainly used to improve the coding efficiency of screen content video.
  • the IBC mode is a block-level coding mode.
  • a block matching (BM) method is used to find the best block vector or motion vector for each CU.
  • the motion vector here is mainly used to represent the displacement from the current block to the reference block, which is also called displacement vector.
  • the reference block is a reconstructed block in the current image.
  • the IBC mode can be considered as a third prediction mode other than the intra prediction mode or the inter prediction mode.
  • the IBC mode in VTM4 only allows prediction using the reconstructed part of a predefined area of the current CTU.
  • an identification bit is used to indicate whether the current CU uses the IBC mode.
  • the IBC mode is divided into an IBC AMVP mode, an IBC skip mode, or an IBC merge mode.
  • FIG. 9 shows a method flowchart 900 of the first embodiment of the present invention.
  • Step 901 Determine whether the current node needs to be divided, and the current node includes a luma block and a chroma block. If the current node is no longer divided into child nodes, the current node is a coding unit (CU), and step 910 is performed to parse the coding unit information; if the current node needs to be divided, step 902 is performed.
  • CU coding unit
  • the first embodiment of the present invention may be implemented by a video decoding device, and specifically may be any of the devices described in FIGS. 3-5.
  • the first embodiment of the present invention may also be implemented by a video encoding device, and specifically may be the device described in any one of FIGS. 2 and 4-5.
  • step 902 The video decoding device parses the bitstream to determine the current node division mode.
  • the current node can be divided into at least one of QT, horizontal BT, horizontal TT, vertical BT, and vertical TT. Other division manners are also possible, which are not limited in the embodiment of the present invention.
  • Information about the current node's division method is usually transmitted in the code stream, and the current node's division method can be obtained by analyzing the corresponding syntax elements in the code stream.
  • step 902 a division method of a current node is determined.
  • Step 904 Determine whether the chrominance block of the current node needs to be divided according to the division manner of the current node and the size of the current node. When the chroma block of the current node is no longer divided, step 906 is performed; when the chroma block of the current node needs to be divided, step 908 is performed.
  • the current node division it can be determined whether the current node division according to the current node division method will generate a chroma block with an edge length of the first threshold (or whether a chroma block with an edge length less than the second threshold will be generated). . If it is determined that the child node generated by the current node division includes a chroma block with a side length of a first threshold (or a chroma block with a side length less than a second threshold), the chroma block of the current node is no longer divided.
  • the first threshold may be 2 and the second threshold may be 4.
  • a chroma block with a side length of the first threshold refers to a chroma block with a width of the first threshold or a height of the first threshold.
  • Condition 1 The width of the current node is equal to twice the second threshold, and the current node is divided into two types.
  • Condition 2 The height of the current node is equal to twice the second threshold and the current node is divided into two levels.
  • Condition 3 The width of the current node is equal to 4 times the second threshold, and the current node is divided into vertical thirds.
  • Condition 4 The height of the current node is equal to 4 times the second threshold and the current node is divided into three levels.
  • Condition 5 The width of the current node is equal to twice the second threshold and the current node is divided into four points.
  • the width of the current node is the width of the luma block corresponding to the current node
  • the height of the current node is the height of the luma block corresponding to the current node.
  • the second threshold may be 4.
  • the current node division it can be judged whether the current node division according to the current node division manner will generate a chroma block that is wider than the first threshold (or whether it will generate a chroma block that is wider than the second threshold). If it is determined that the child node generated by the current node division includes a chroma block having a width that is a first threshold (or a chroma block having a width that is less than a second threshold), the chroma block of the current node is no longer divided.
  • the first threshold may be 2 and the second threshold may be 4.
  • a fourth implementation manner it can be determined whether the current node division according to the current node division manner will generate a chroma block with a number of chroma pixels less than a third threshold. If it is determined that the child node generated by the current node division includes a chroma block with a number of chroma pixels less than a third threshold, the chroma block of the current node is no longer divided.
  • the third threshold may be 16.
  • the chroma block with the number of chroma pixels less than 16 includes, but is not limited to, a 2x2 chroma block, a 2x4 chroma block, and a 4x2 chroma block.
  • the third threshold may be eight. Then, chroma blocks with a number of chroma pixels less than 8 include, but are not limited to, 2 ⁇ 2 chroma blocks.
  • Condition 1 The product of the width and height of the current node is less than 128 and the current node is divided into two types: vertical bisect or horizontal dichotomy.
  • Condition 2 The product of the width and height of the current node is less than 256 and the current node is divided into three vertical or horizontal three or four.
  • the current node division according to the current node division manner will generate a chroma whose number of chroma pixels is less than the third threshold. Block; otherwise, it can be judged that the current node's division according to the current node's division method will not produce a chroma block whose number of chroma pixels is less than the third threshold:
  • Condition 3 The product of the width and height of the current node is equal to 64 and the current node is divided into two types: vertical halves, horizontal halves or quarters, horizontal halves, or vertical halves.
  • Condition 4 The product of the width and height of the current node is equal to 128 and the division method of the current node is a vertical third or a horizontal third.
  • a fifth implementation manner it can be judged whether the current node division according to the current node division manner will generate a chroma block that is higher than the first threshold (or whether a chroma block that is higher than the second threshold will be generated). If it is determined that the child node generated by the current node division includes a chroma block that is high to a first threshold (or includes a chroma block that is higher than a second threshold), the chroma block of the current node is no longer divided.
  • the first threshold may be 2 and the second threshold may be 4.
  • Step 906 Divide the luma block of the current node according to the division method of the current node to obtain the child nodes of the current node (also referred to as the child nodes of the luma block, referred to as the luminance node). Each child node contains only luma blocks. The chroma block of the current node is no longer divided and becomes a coding unit containing only chroma blocks.
  • step 906 may further include step 9062: parsing the luma block of the current node, and obtaining prediction information and residual information of each sub-region in the luma block of the current node, where each sub-region is related to One child node corresponds.
  • step 9062 may be implemented by using any of the following methods:
  • Method 1 The child nodes of each luminance block are no longer divided by default (that is, each luminance node is a coding unit, and a child of a luminance block corresponds to a coding unit containing only a luminance block), and the child nodes of each luminance block are sequentially parsed and encoded. Unit data to obtain prediction information and residual information for each luma block.
  • the brightness block of a brightness node is a sub-area of the brightness block of the current node, and the brightness blocks of each brightness node constitute the brightness block of the current node. or;
  • Method 2 The child nodes of each luma block are sequentially judged whether it is necessary to continue to divide, and when it is necessary to continue to divide, analyze their division mode and corresponding coding unit data. More specifically, if a brightness node is no longer divided, the corresponding coding unit data is parsed to obtain prediction information and residual information corresponding to the brightness block of this brightness node; if a brightness node continues to be divided, the The child node (it should be noted that the child node still only contains the luma block) continues to determine whether it needs to be divided until the prediction information and residual information of each sub-region in the luma block of the current node are determined.
  • the prediction information includes, but is not limited to, a prediction mode (indicating an intra prediction or an inter prediction mode), an intra prediction mode, and / or motion information.
  • the intra prediction mode of the luma block can be one of a planar mode, a DC mode, a DC mode, an angular mode, and a chroma derived mode (DM); the motion information may include a prediction direction (Forward, backward, or bidirectional), reference frame index, and / or motion vector.
  • the residual information includes: a coded block flag (cbf), a transform coefficient, and / or a transform type (for example, DCT-2, DST-7, DCT-8) and the like.
  • step 906 may further include step 9064: acquiring prediction information and / or residual information of the chroma block.
  • step 9064 may include steps 90642 and 90644.
  • Step 90642 may be step 90642A or step 90642B.
  • Step 90642A specifically includes:
  • the position of the upper left corner of the luma block of the current node can be expressed as (x0, y0) and the size is WxH.
  • the preset position can include, but is not limited to, the upper left and lower right corners of the luma block (x0 + W-1, y0 + H- 1), center (x0 + W / 2, y0 + H / 2), (x0 + W / 2, 0), (0, y0 + H / 2), etc.
  • the prediction mode indicates whether to use intra prediction or inter prediction to predict a pixel at a preset position, for example, information indicated by a pred_mode_flag syntax element in HEVC.
  • a pred_mode_flag syntax element in HEVC.
  • the prediction mode of the preset position is the IBC mode according to the information indicated by the syntax element pred_mode_ibc_flag.
  • the prediction mode for the preset position is inter prediction, use one of the following methods to determine the prediction mode for chrominance:
  • Method 1 The chrominance block uses inter prediction to obtain motion information of a preset position as motion information of the chrominance block.
  • Method 2 Inter-prediction is used for chroma blocks, and chroma blocks are divided into chroma prediction sub-blocks (the chroma prediction sub-block size is, for example, 2 chroma pixels wide and 2 chroma pixels high), and chroma prediction
  • the motion information of the sub-block is obtained in the following manner:
  • the motion information of the luma image position corresponding to the chroma prediction subblock is used as the motion information of the chroma prediction subblock; otherwise, a preset position is obtained
  • the motion information is used as the motion information of the chroma prediction sub-block.
  • the position of the chroma prediction subblock in the chroma image is (xC, yC), then the coordinates of the position of the luma image corresponding to the chroma prediction subblock are (xC ⁇ 1, yC ⁇ ⁇ 1).
  • Method 3 Parse the pred_mode_flag flag to determine whether the chroma block uses intra prediction or inter prediction. If the chroma block uses intra prediction, parse an intra prediction mode from the code stream as the intra prediction mode of the chroma block. ; If the chrominance block uses inter prediction, motion information of a preset position is obtained as the motion information of the chrominance block.
  • Method 4 Parse the pred_mode_flag flag to determine whether the chrominance block uses intra prediction or inter prediction. If the chrominance block uses intra prediction, parse an intra prediction mode from the code stream as the intra prediction mode of the chrominance block. , Where the intra prediction mode can be one of a linear model mode and a DM mode, and the luminance intra prediction mode corresponding to the DM mode is set to a flat mode; if the chroma block uses inter prediction, the chroma block is divided into colors Degree prediction subblocks, and motion information of chroma prediction subblocks are obtained in the following manner:
  • the motion information of the luma image position corresponding to the chroma prediction subblock is used as the motion information of the chroma prediction subblock; otherwise, a preset position is obtained
  • the motion information is used as the motion information of the chroma prediction sub-block.
  • the context model used when parsing the pred_mode_flag flag is a preset model, for example, the model number is 2.
  • the chroma block uses intra prediction, and an intra prediction mode is parsed from the code stream as the intra prediction mode of the chroma block.
  • the intra prediction mode of the chroma block is one of a DC mode, a plane mode, an angle mode, a linear model mode, or a DM mode.
  • the chroma block uses the IBC mode for prediction, and obtains displacement vector information of the preset position as the displacement vector information of the chroma block.
  • the prediction mode of the preset position is the IBC mode
  • the prediction mode of the chroma block is determined according to the flag bit pred_mode_ibc_flag:
  • the chroma block uses the IBC mode; more specifically, the IBC prediction method of the chroma block can use the method in VTM 4.0, that is, the chroma block is divided into 2x2 sub-blocks.
  • the displacement vector is equal to the displacement vector of the luminance region corresponding to the sub-block.
  • pred_mode_ibc_flag 0 If pred_mode_ibc_flag is 0, the chroma block uses an intra prediction mode or an inter prediction mode.
  • the syntax element is parsed from the code stream to determine the intra prediction mode of chrominance.
  • the intra prediction mode of the chroma block is one of a set of intra prediction modes of chroma, and the set of chroma intra prediction modes are: DC mode, plane mode, angle mode, linear model, DM mode.
  • motion information of a preset position can be acquired as motion information of a chroma block.
  • pred_mode_ibc_flag when pred_mode_ibc_flag does not exist in the code stream, if the image type of the current node is I-frame / I-strip and IBC mode is allowed, the default pred_mode_ibc_flag is 1, that is, the chroma block uses IBC mode by default; If the picture type is P / B frame / slice, the default pred_mode_ibc_flag is 0.
  • the VTM may determine whether the prediction mode of the preset position is an IBC mode according to the information indicated by the syntax element pred_mode_ibc_flag. For example, a pred_mode_ibc_flag of 1 indicates that the IBC prediction mode is used, and 0 indicates that the IBC mode is not used.
  • pred_mode_ibc_flag does not appear in the code stream, if the value of pred_mode_ibc_flag is the same as the value of sps_ibc_enabled_flag in the I frame / I slice, if in the P frame / slice or B frame / strip, the pred_mode_ibc_flag is 0.
  • sps_ibc_enabled_flag 1 means that the current picture is allowed as a reference picture during the decoding of the current picture
  • sps_ibc_enabled_flag 0 means that the current picture is not allowed to be used as the reference picture during the decoding of the current picture.
  • the intra prediction mode of the chrominance block may be one of a DC mode, a planar mode, an angular mode, a cross-component linear model (CCLM) mode, and a chroma derived mode (DM).
  • DC mode plane mode, angle mode, linear model mode, and chroma export mode in VTM.
  • Step 90642B specifically includes:
  • the chroma block uses intra prediction, and an intra prediction mode is parsed from the code stream as the intra prediction mode of the chroma block.
  • Method 1 The chrominance block uses inter prediction to obtain motion information of a preset position as motion information of the chrominance block.
  • the preset position has the same meaning as in the first embodiment.
  • Method 2 Parse the pred_mode_flag flag to determine whether the chroma block uses intra prediction or inter prediction. If the chroma block uses intra prediction, parse an intra prediction mode from the code stream as the intra prediction mode of the chroma block ; If the chrominance block uses inter prediction, motion information of a preset position is obtained as the motion information of the chrominance block.
  • the mode information of the chroma blocks can be determined in one of the following ways:
  • the chroma block uses inter prediction to obtain motion information of the preset position as motion information of the chroma block.
  • the chroma block uses intra prediction, and an intra prediction mode is parsed from the code stream as the intra prediction mode of the chroma block.
  • the intra prediction mode of the chroma block is one of a DC mode, a plane mode, an angle mode, a linear model mode, or a DM mode.
  • the chroma block uses the IBC mode for prediction, and obtains the displacement vector information of the preset position as the displacement vector information of the chroma block.
  • the prediction mode that directly specifies the chroma is one of the mode sets, and the mode sets are AMVP mode, IBC mode, skip mode, DC mode, plane mode, angle mode, linear model mode, and DM mode.
  • Step 9044 Parse residual information of the chroma block.
  • the residuals of the chrominance blocks are contained in a transform unit.
  • the transformation type can default to DCT-2 transformation.
  • Step 908 Divide the current node into child nodes, and each child node includes a luma block and a chroma block. Step 901 is performed for each child node, and the division manner of the child nodes is continuously analyzed to determine whether each child node (also referred to as a node) still needs to be divided.
  • the inter prediction processing or intra prediction processing can be performed on each subregion according to the corresponding prediction mode of each subregion to obtain the subregion's Inter-predicted or intra-predicted images.
  • the transform coefficient is subjected to inverse quantization and inverse transform processing to obtain a residual image, which is superimposed on the predicted image of the corresponding sub-region to generate a reconstructed image of the luminance block.
  • the inter prediction process or the intra prediction process can be performed on the chroma block according to the prediction mode of the chroma block to obtain the inter-prediction image or the intra-prediction image of the chroma block.
  • the transform coefficient is subjected to inverse quantization and inverse transformation processing to obtain a residual image, which is superimposed on the prediction image of the chrominance block to generate a reconstructed image of the chrominance block.
  • the method when the chroma blocks of the current node are no longer divided, the method can only divide the luma blocks of the current node, thereby improving the encoding and decoding efficiency and reducing the maximum throughput of the decoder, which is beneficial Decoder implementation.
  • step 9062 adds the following restriction condition: each brightness node (that is, a child node of each brightness block) uses the same prediction mode, that is, each brightness node uses intra prediction or all uses inter prediction.
  • each brightness node uses the same prediction mode, that is, each brightness node uses intra prediction or all uses inter prediction.
  • the other steps are similar to those of the first embodiment and will not be described again.
  • Each brightness node can use the same prediction mode by using any of the following methods:
  • Method 1 If the current frame is an I-frame, each child node of the current node uses intra prediction by default; if the current frame is a P-frame or a B-frame, the first node that can be parsed (may be referred to as the first one) Sub-nodes) to obtain its prediction mode by parsing, and the prediction modes of the remaining sub-nodes (referred to as luminance nodes for short) default to the prediction mode of the first node that performs the parsing process. or
  • Method 2 If the current frame is an I frame, each child node of the current node uses intra prediction by default; if the current frame is a P frame or B frame, each child node of the current node uses inter prediction by default.
  • FIG. 11 shows a method flowchart 1100 of a third embodiment of the present invention.
  • the third embodiment is similar to the first embodiment, except for step 1104.
  • Step 1104 judging the current node according to the current node division method, the size of the current node, and the prediction mode of the first node (which may be referred to as the first child node) of the current node for parsing processing. Whether the chrominance block of a node is divided, and the first child node only includes a luma block. Multiple child nodes of the current node use the same prediction mode, where each child node contains only luma blocks.
  • this embodiment of the present invention does not limit it.
  • the third embodiment is based on the first or second embodiment and combines the prediction mode of the first child node of the current node to determine the division mode of the current node chroma block and the corresponding prediction information and residual information analysis mode.
  • the child node generated by dividing the current node includes a chromaticity with an edge length equal to a first threshold value or an edge length less than a second threshold value.
  • Block, and the prediction mode of the first child node is intra prediction, the chroma block of the current node is no longer divided.
  • the first threshold may be 2 and the second threshold may be 4.
  • a chroma block with a side length of the first threshold refers to a chroma block with a width of the first threshold or a height of the first threshold.
  • Condition 1 The width of the current node is equal to 2 times the second threshold and the current node is divided into vertical dichotomies; or
  • Condition 2 The height of the current node is equal to twice the second threshold and the current node is divided into two levels; or
  • Condition 3 The width of the current node is equal to 4 times the second threshold and the current node is divided into vertical three points; or
  • Condition 4 The height of the current node is equal to 4 times the second threshold and the current node is divided into three levels; or
  • Condition 5 The width of the current node is equal to two times the second threshold and the current node is divided into four quarters, so the chrominance block of the current node is no longer divided.
  • the width of the current node is the width of the luma block corresponding to the current node
  • the height of the current node is the height of the luma block corresponding to the current node.
  • the second threshold may be 4.
  • the prediction mode of the first child node is intra prediction, similar to the first embodiment, in a third implementation manner, it can be judged whether the current node's division according to the current node's division mode will generate a wide threshold. (Or whether a chroma block with a width smaller than the second threshold will be generated). If it is determined that the child node generated by the current node division includes a chroma block with a width that is first than the threshold (or includes a chroma block with a width that is less than the second threshold), and the prediction mode of the first child node is intra prediction , The chrominance block of the current node is no longer divided.
  • the first threshold may be 2 and the second threshold may be 4.
  • the prediction mode of the first child node is intra prediction, similar to the first embodiment, in a fourth implementation manner, it can be judged whether the current node is divided according to the current node division method to generate a small number of chroma pixels.
  • a chroma block at a third threshold If it is determined that the child node generated by the current node division includes a chroma block with a number of chroma pixels less than a third threshold, and the prediction mode of the first child node is intra prediction, the chroma of the current node The blocks are no longer divided.
  • the third threshold may be 16.
  • the chroma block with the number of chroma pixels less than 16 includes but is not limited to a 2x2 chroma block, a 2x4 chroma block, and a 4x2 chroma block.
  • the third threshold may be eight.
  • chroma blocks with a number of chroma pixels less than 8 include, but are not limited to, 2 ⁇ 2 chroma blocks.
  • Condition 1 The product of the width and height of the current node is less than 128 and the current node is divided into two types: vertical bisector or horizontal dichotomy.
  • Condition 2 The product of the width and height of the current node is less than 256 and the current node is divided into three vertical or horizontal three or four.
  • the current node division according to the current node division manner will generate a chroma whose number of chroma pixels is less than the third threshold. Block; otherwise, it can be judged that the current node's division according to the current node's division method will not produce a chroma block whose number of chroma pixels is less than the third threshold:
  • Condition 3 The product of the width and height of the current node is equal to 64 and the current node is divided into two types: vertical halves, horizontal halves or quarters, horizontal halves, or vertical halves.
  • Condition 4 The product of the width and height of the current node is equal to 128 and the division method of the current node is a vertical third or a horizontal third.
  • the prediction mode of the first child node is intra prediction, similar to the first embodiment, in a fifth implementation manner, it can be determined whether the current node's division according to the current node's division mode will generate a high threshold. (Or whether a chroma block with a height less than the second threshold will be generated). If it is determined that the child node generated by the current node division includes a chroma block that is higher than the first threshold (or includes a chroma block that is higher than the second threshold), and the prediction mode of the first child node is intra prediction , The chrominance block of the current node is no longer divided.
  • the first threshold may be 2 and the second threshold may be 4.
  • the method 1100 may further include obtaining prediction information and / or residual information of the chroma block.
  • a child node generated by dividing the current node includes a chroma block with an edge length less than a threshold.
  • the prediction mode of the child node is inter prediction, and then the chrominance block of the current node is divided according to the division mode of the current node.
  • the motion information of the corresponding child node of the chroma block is determined according to the motion information of the child node of the current node.
  • the motion information of the child nodes of the chroma block of the current node may be set to the motion information of the corresponding luminance node (that is, the motion information of each child node of the chroma block does not need to be parsed from the code stream).
  • the residual information is analyzed separately to obtain the residual information of each child node of the chroma block.
  • Condition 1 The width of the current node is equal to 2 times the second threshold and the current node is divided into vertical dichotomies; or
  • Condition 2 The height of the current node is equal to twice the second threshold and the current node is divided into two levels; or
  • Condition 3 The width of the current node is equal to 4 times the second threshold and the current node is divided into vertical three points; or
  • Condition 4 The height of the current node is equal to 4 times the second threshold and the current node is divided into three levels; or
  • Condition 5 The width of the current node is equal to two times the second threshold and the current node is divided into quarters, and the chrominance block of the current node still needs to be divided.
  • the width of the current node is the width of the luma block corresponding to the current node
  • the height of the current node is the height of the luma block corresponding to the current node.
  • the second threshold may be 4.
  • the division mode of the chrominance block and the corresponding prediction information and residual information analysis mode can also be determined according to the prediction mode of the luminance node, which has stronger flexibility. Moreover, when the prediction mode of the luminance node is intra prediction, the chroma blocks of the current node are no longer divided, which can improve the chroma encoding and decoding efficiency, reduce the maximum throughput of the decoder, and facilitate the implementation of the decoder.
  • Part of the CU-level syntax structure can be shown in Table 1. If the current node is no longer divided into child nodes, the current node is a coding unit, and the prediction block of the coding unit is parsed according to the following syntax structure.
  • skip_flag is a flag of skip mode
  • a value of 1 indicates that the current CU uses the skip mode
  • a value of 0 indicates that the current CU does not use the skip mode.
  • merge_flag is a direct mode flag. A value of 1 indicates that the current CU uses the merge mode; a value of 0 indicates that the merge mode is not used.
  • cu_pred_mode is a coding unit prediction mode flag. A value of 1 indicates that the current prediction unit uses the intra prediction mode; a value of 0 indicates that the current prediction unit uses the ordinary inter prediction mode.
  • cu_skip_flag is a flag of skip mode, a value of 1 indicates that the current CU uses the skip mode, and a value of 0 indicates that the current CU does not use the skip mode.
  • merge_flag is a direct mode flag. A value of 1 indicates that the current CU uses the merge mode; a value of 0 indicates that the merge mode is not used.
  • pred_mode_flag is a coding unit prediction mode flag. A value of 1 indicates that the current prediction unit uses the intra prediction mode; a value of 0 indicates that the current prediction unit uses the ordinary inter prediction mode. If pred_mode_flag is 1, CuPredMode [x0] [y0] is CuPredMode [x0] [y0] is MODE_INTRA; if pred_mode_flag is 0, CuPredMode [x0] [y0] is MODE_INTER.
  • An 8xM (or Mx8) -sized node is divided into two sub-nodes of 4xM (or Mx4) size using vertical bisection (or horizontal dichotomy) division; similarly, a 16xM (or Mx16) -sized node uses four vertical expansion Dividing (or horizontally expanding quarterly) division will produce four 4xM (or Mx4) child nodes and one 8xN (or Nx8) child node. Similarly, a 16xM (or Mx16) -sized node is divided into vertical threes (or horizontal threes) to generate two 4xM (or Mx4) child nodes and one 8xM (or Nx8) child node.
  • the resolution of the chrominance component is 1/2 of the luminance component, that is, a 4xM node contains a 4xM luminance block and two 2x (M / 2) chrominance blocks.
  • small blocks especially 2x2, 2x4, 2x8 are more expensive to process.
  • this partitioning method will generate 2x2, 2x4 and other small blocks, which is not conducive to the implementation of the hardware decoder.
  • the processing complexity of small blocks is relatively high, including the following three aspects.
  • Intra prediction In order to improve the processing speed in hardware design, intra prediction usually processes 16 pixels at a time, and 2x2, 2x4, 4x2 and other small blocks contain less than 16 pixels, which reduces the processing performance of intra prediction. .
  • Coefficient coding problem The transform coefficient coding in HEVC is based on a coefficient group (CG) containing 16 coefficients, and the small blocks of 2x2, 2x4, and 4x2 contain 4 or 8 transform coefficients, which leads to the need to increase the
  • the coefficient groups of 4 coefficients and 8 coefficients support the coefficient coding of these small blocks, thus increasing the implementation complexity.
  • Inter-prediction problem Inter-prediction of small blocks has high requirements on data bandwidth and also affects the processing speed of decoding.
  • a node uses a division method to continue to divide, and one of the children contains a chroma block with a side length of 2, the luma blocks included in the children are continued to be divided using this division. The included chroma blocks are no longer divided. In this way, it is possible to avoid generating chroma blocks with a side length of 2 and reduce the maximum throughput of the decoder, which is beneficial to the implementation of the decoder.
  • a method for determining the chroma block prediction mode according to the luma block prediction mode is proposed, which effectively improves the coding efficiency.
  • the method provided by the present invention can be applied to the video codec of the foregoing embodiment.
  • the video data format in this embodiment is a YUV4: 2: 0 format.
  • a similar approach can be used for YUV4: 2: 2 data.
  • Step 1 Analyze the division method S of node A. If node A continues to divide, go to step 2. If the current node is no longer divided into child nodes, the current node corresponds to a coding unit and parse the coding unit information;
  • the division manner of the node A may be at least one of quad-tree division, vertical bisection, horizontal bisection, vertical trisection, and horizontal trisection, and may also be other division manners, which is not limited in the present invention.
  • Information about the current node's division method can be transmitted in the code stream, and the current node's division method can be obtained by analyzing the corresponding syntax elements in the code stream.
  • the current node division manner may also be determined based on a preset rule, which is not limited in the present invention.
  • Step 2 Determine whether the chromaticity block of at least one child node B among the child nodes obtained by the division by the node S according to the division method S is a small block (determine the width and height of the node A, and / or the division method, and / Or whether the width and height of the node B satisfy at least one of the conditions). If the chrominance block of at least one child node B among the child nodes obtained by node A is a small block, perform steps 3 to 6
  • the method for determining whether the chrominance block of at least one child node B of the node A is a small block may use one of the following.
  • the chroma block of at least one child node B of node A is 2x2, 2x4, or 4x2 size, then the chroma block of at least one child node B of node A is a small block.
  • the chroma block of at least one child node B of node A is 2 If the width or height of the chroma block of at least one child node B of node A is 2, the chroma block of at least one child node B of node A is a small block.
  • node A contains 128 luminance pixels and node A uses a tri-tree partition, or if node A contains 64 luminance pixels and node A uses a binary tree partition or a quad-tree partition or a tri-tree partition, at least one child of node A
  • the chrominance block of node B is a small block.
  • node A contains 256 luminance pixels and the node uses tri-tree or quad-tree partitioning, or if node A contains 128 luminance pixels and the node uses binary tree division, then the chroma block of at least one child node B of node A For small pieces.
  • N1 is 64, 128, or 256.
  • N2 is 64 or 256.
  • N3 is 64, 128, or 256.
  • the node A includes 128 brightness pixels can also be described as the area of the current node is 128, or the product of the width and height of the node A is 128, and details are not described herein.
  • Step 3 Restrict all coding units in the coverage area of node A to use intra prediction or to use inter prediction.
  • intra and inter prediction are used, which can realize the parallel processing of small blocks by hardware and improve the performance of encoding and decoding.
  • All coding units in the coverage area of Node A use intra prediction or all inter prediction can be determined by one of the following methods.
  • Method 1 Determine according to the flag bit in the syntax table.
  • cons_pred_mode_flag can be a syntax element that needs to be parsed during the block division process. When the syntax element is parsed, the cu_pred_mode of the coding unit of the coverage area of node A can no longer be parsed, and its value corresponds to the default value of cons_pred_mode_flag.
  • node A can only use the intra prediction mode, for example, node A is in the intra image (that is, the image type of node A is Intra or I type), or node A is in the intra image.
  • the sequence does not use IBC technology, cons_pred_mode_flag defaults to 1 and does not appear in the code stream.
  • the IBC technology may belong to inter prediction or intra prediction.
  • Method 2 Determine the prediction mode of the first node in the node A area.
  • the prediction mode of the first coding unit B0 is not limited. If the prediction mode of B0 is intra prediction, all coding units in the coverage area of node A use frames. Intra-prediction; if the prediction mode of B0 is inter-prediction, all coding units in the cover area of the node A area use inter-prediction.
  • Step 4 According to the prediction mode used by the coding unit of the coverage area of the node A, determine the division method of the chroma block and the luma block of the node A.
  • the luminance block of node A is divided according to the division method S to obtain N luminance coding tree nodes; the chrominance block of node A is not divided.
  • the N luminance coding tree nodes may be restricted to not continue to divide, or not to be restricted.
  • the division method is analyzed for recursive division. When the luminance coding tree node is no longer divided, it corresponds to a luminance coding block (referred to as luminance CB).
  • the chroma transform block corresponding to the chroma CB is the same size as the chroma coding block, and the chroma prediction block and the chroma coding block are the same size.
  • the luminance block and chrominance block of node A are further divided into N coding tree nodes including the luma block and the chroma block according to the division method S.
  • the N The coding tree node may continue to be divided or not divided, and when not divided, it corresponds to a coding unit including a luma block and a chroma block.
  • Step 5 Parse the prediction block and residual information of the CU obtained by the node A partition.
  • the prediction block includes a prediction mode (indicating an intra prediction mode or a non-intra prediction mode), an intra prediction mode, an inter prediction mode, motion information, and the like.
  • the motion information may include information such as a prediction direction (forward, backward, or bidirectional), a reference frame index (reference index), a motion vector (motion vector), and the like.
  • the residual information includes: a coded block flag (cbf), a transform coefficient, a transform type (for example, DCT-2, DST-7, DCT-8), and the like.
  • the transformation type can default to DCT-2 transformation.
  • the analysis of the prediction block of brightness CB obtained by node A includes skip_flag, merge_flag, and cu_pred_mode, which are defaulted to 0, 0, and 1 (that is, skip_flag, merge_flag, cu_pred_mode (Both do not appear in the code stream), or skip_flag and cu_pred_mode default to 0 and 1 respectively (that is, neither skip_flag nor cu_pred_mode appear in the code stream) will analyze the intra prediction mode information of the luminance CB; the chroma obtained by the node A division
  • the CB prediction block analysis includes parsing the intra prediction mode of the chroma CB.
  • the chroma CB intra prediction mode analysis method can be: 1) obtained by parsing syntax elements from the code stream; 2) directly set to one of the chroma intra prediction mode set, such as linear model mode, DM mode (chroma derived mode, DM) and IBC mode.
  • parsing the prediction mode of CU obtained by node A includes parsing skip_flag or / and merge_flag, defaulting cu_pred_mode to 0, and parsing inter prediction blocks, such as fusion index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector predictor index (motion vector predictor index), and motion vector difference (motion vector difference)
  • skip_flag is a flag of skip mode, a value of 1 indicates that the current CU uses the skip mode, and a value of 0 indicates that the current CU does not use the skip mode.
  • merge_flag is a merge mode flag. A value of 1 indicates that the current CU uses the merge mode; a value of 0 indicates that the merge mode is not used.
  • cu_pred_mode is the coding unit prediction mode flag, a value of 1 indicates that the current prediction unit uses intra prediction; a value of 0 indicates that the current prediction unit uses ordinary inter prediction (identifies the inter prediction direction, reference frame index, and motion vector prediction in the code stream Value index, motion vector difference, etc.).
  • the intra prediction mode described in this embodiment is a prediction mode that uses the spatial reference pixels of the image where the coding block is located to generate the prediction value of the coding block, such as a direct current mode (DC mode) and a planar mode ( Planar mode), angular mode, may also include template matching mode (template matching mode), IBC mode.
  • DC mode direct current mode
  • Planar mode planar mode
  • IBC mode template matching mode
  • the inter prediction mode is a prediction mode for generating a prediction value of a coded block using a time-domain reference pixel in a reference image of the coded block, such as a skip mode, a merge mode, and an AMVP (advanced motion vector) prediction) mode or common Inter mode, IBC mode, etc.
  • a prediction mode for generating a prediction value of a coded block using a time-domain reference pixel in a reference image of the coded block, such as a skip mode, a merge mode, and an AMVP (advanced motion vector) prediction) mode or common Inter mode, IBC mode, etc.
  • Step 6 Decode each CU to obtain the reconstructed signal of the image block corresponding to node A
  • an inter-prediction process or an intra-prediction process is performed on each CU by a prediction block of each CU to obtain an inter-prediction image or an intra-prediction image of each CU. Then, according to the residual information of each CU, the transform coefficient is subjected to inverse quantization and inverse transform processing to obtain a residual image, which is superimposed on the predicted image of the corresponding area to generate a reconstructed image.
  • Step 1, step 2, step 3, and step 6 of this embodiment are the same as those of the fourth embodiment.
  • Step 4 Determine the division method of the chroma block and the luma block of the node A.
  • the luminance block of node A is further divided according to the division method S, and N luminance-coding tree nodes are generated.
  • the chroma block of node A is no longer divided, and corresponds to a chroma coding block (chroma CB).
  • the chroma transform block corresponding to the chroma CB is the same size as the chroma coding block.
  • Step 5 Parse the prediction block and residual information of the CU obtained by the node A partition.
  • the analysis of the prediction block of brightness CB obtained by node A includes parsing skip_flag or / and merge_flag, defaulting cu_pred_mode to 0, and parsing inter prediction blocks, such as fusion Index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector predictor index (motion vector predictor index) and motion vector difference (motion vector difference).
  • inter prediction blocks such as fusion Index (merge index), inter prediction direction (inter dir), reference frame index (reference index), motion vector predictor index (motion vector predictor index) and motion vector difference (motion vector difference).
  • each CU obtained by node A is restricted to use inter prediction only, the prediction block of chroma CB obtained by node A does not need to be parsed, and chroma CB is divided into 2x2 chroma sub-blocks (the division method may be a division method) S), the motion information of each 2x2 chroma subblock is the motion information of a 4x4 luminance region corresponding to each 2x2 chroma subblock.
  • Embodiment 5 solves the above-mentioned intra prediction problem and coefficient encoding problem.
  • Step 1, step 2, step 3, step 4, step 6 of this embodiment are the same as those of the fifth embodiment.
  • Step 5 Parse the prediction block and residual information of the CU obtained by the node A partition.
  • each CU obtained by the node A division is limited to inter prediction only, the analysis of the prediction block of the brightness CB obtained by the node A division is the same as that in the fifth embodiment.
  • the chroma prediction block is the same size as the chroma coded block.
  • the motion information of chroma CB is Motion information of a preset position in the luminance area corresponding to the chroma CB (such as the center of the luminance area, the lower right corner or the upper left corner, etc.).
  • Step 1 Same as step 1 in the fourth embodiment
  • Step 2 Determine whether there is at least one child node B with a brightness block of 4 ⁇ 4 in the child nodes obtained by node A according to the division method S (determine the width, height, and / or division method of node A, and And / or whether the width and height of the node B satisfy at least one of the conditions in the first case).
  • the size (width, height) of the node A, and / or the division mode S meets at least one of the conditions in the first case, then all coding units in the coverage area of the node A are restricted from using intra prediction. Otherwise, it is determined whether the chromaticity block of at least one child node B among the child nodes obtained by the node A according to the division method S is a small block (the size of the node A, and / or the division method S, and / or the node If the width and height of B satisfy at least one of the conditions in the second case, perform step 3 to step 6.
  • the method for judging that the chrominance block of at least one child node B of the node A is a small block is divided into the following two cases.
  • the node A will obtain a 4x4 luminance block according to the division method S:
  • Node A contains M1 pixels and the division method of node A is quadtree partition, for example, M1 is 64;
  • Node A contains M2 pixels and the division method of node A is tri-tree partition, for example, M2 is 64;
  • Node A contains M3 pixels and the division method of node A is binary tree partition, for example, M3 is 32;
  • the width of node A is equal to the second threshold and the height is equal to 4 times the second threshold, and the division of node A is a horizontal tri-tree partition;
  • the height of node A is equal to twice the second threshold, the width of node A is equal to the second threshold, and the current node is divided into two levels;
  • the width or / and height of node A is twice the second threshold and the partitioning method of node A is quadtree partitioning.
  • the size may be the width and height of the image area corresponding to node A, the number of luminance pixels contained in the image area corresponding to node A, or the area of the image area corresponding to node A.
  • the width of the current node is the width of the luma block corresponding to the current node
  • the height of the current node is the height of the luma block corresponding to the current node.
  • the second threshold may be 4.
  • node A contains 128 luminance pixels and node A uses a tri-tree partition, or if node A contains 64 luminance pixels and node A uses a binary tree partition or a quad-tree partition or a tri-tree partition;
  • node A contains 256 luminance pixels and the node uses tri-tree or quad-tree partition, or if node A contains 128 luminance pixels and the node uses binary tree division;
  • N1 is 64, 128, or 256.
  • N2 is 64 or 256.
  • N3 is 64, 128, or 256.
  • the node A includes 128 brightness pixels can also be described as the area of the current node is 128, or the product of the width and height of the node A is 128, and details are not described herein.
  • Step 3 It is the same as Step 3 in the fourth embodiment.
  • Step 4 According to the prediction mode used by the coding unit of the coverage area of the node A, determine the division method of the chroma block and the luma block of the node A.
  • the luminance block and chrominance block of node A are divided according to the division method S to obtain the child nodes in the area covered by node A or / and node A.
  • the division mode of the child node is not allowed or the child node cannot continue to be divided.
  • node A For example, if the size of node A is 8x8 and using a horizontal binary tree (or vertical binary tree) partition to generate two 8x4 (or two 4x8) nodes, continued partitioning of 8x4 (or 4x8) nodes will produce 4x4 blocks, so At this time, 8x4 (or 4x8) nodes cannot be divided.
  • the implementation method can use the methods in implementation four, five, and six, and details are not described herein. For example, the luminance block of node A is divided, and the chrominance block is not divided.
  • Step 5 Parse the prediction block and residual information of the CU obtained by the node A partition.
  • step 5 it is the same as step 5 in the fourth embodiment, and details are not described herein.
  • Step 6 Decode each CU to obtain the reconstructed signal of the image block corresponding to node A
  • Step 1 Same as step 1 in the fourth embodiment
  • Step 2 Determine whether there is at least one child node B with a brightness block of 4 ⁇ 4 in the child nodes obtained by node A according to the division method S (determine the width, height, and / or division method of node A, and And / or whether the width and height of the node B satisfy at least one of the conditions in the first case). If the size (width, height) of the node A, and / or the division mode S meets at least one of the conditions in the first case, then all coding units in the coverage area of the node A are restricted from using intra prediction.
  • the chromaticity block of at least one child node B among the child nodes divided by the node A according to the division method S is a small block (determining the size of the node A, and / or the division method S, and / or the node If the width and height of B satisfy at least one of the conditions in the second case, perform step 3 to step 6.
  • the method for judging that the chrominance block of at least one child node B of the node A is a small block is divided into the following two cases.
  • the node A will obtain a 4x4 luminance block according to the division method S:
  • Node A contains M1 pixels and the division method of node A is quadtree partition, for example, M1 is 64;
  • Node A contains M2 pixels and the division method of node A is tri-tree partition, for example, M2 is 128;
  • Node A contains M3 pixels and the division method of node A is binary tree partition, for example, M3 is 32;
  • the width of node A is equal to the second threshold and the height is equal to 4 times the second threshold, and the division of node A is a horizontal tri-tree partition;
  • the height of node A is equal to twice the second threshold, the width of node A is equal to the second threshold, and the current node is divided into two levels;
  • the width or / and height of node A is twice the second threshold and the partitioning method of node A is quadtree partitioning.
  • the size may be the width and height of the image area corresponding to node A, the number of luminance pixels contained in the image area corresponding to node A, or the area of the image area corresponding to node A.
  • the width of the current node is the width of the luma block corresponding to the current node
  • the height of the current node is the height of the luma block corresponding to the current node.
  • the second threshold may be 4.
  • node A contains 128 luminance pixels and node A uses a tri-tree partition, or if node A contains 64 luminance pixels and node A uses a binary tree partition or a quad-tree partition or a tri-tree partition;
  • node A contains 256 luminance pixels and the node uses tri-tree or quad-tree partition, or if node A contains 128 luminance pixels and the node uses binary tree division;
  • N1 is 64, 128, or 256.
  • N2 is 64 or 256.
  • N3 is 64, 128, or 256.
  • the node A includes 128 brightness pixels can also be described as the area of the current node is 128, or the product of the width and height of the node A is 128, and details are not described herein.
  • Step 3 It is the same as Step 3 in the fourth embodiment.
  • Step 4 According to the prediction mode used by the coding unit of the coverage area of the node A, determine the division method of the chroma block and the luma block of the node A.
  • the luminance block and chrominance block of node A are divided according to the division method S to obtain the child nodes in the area covered by node A or / and node A.
  • the division mode of the child node is not allowed or the child node cannot continue to be divided.
  • node A For example, if the size of node A is 8x8 and using a horizontal binary tree (or vertical binary tree) partition to generate two 8x4 (or two 4x8) nodes, continued partitioning of 8x4 (or 4x8) nodes will produce 4x4 blocks, so At this time, 8x4 (or 4x8) nodes cannot be divided.
  • the implementation method can use the methods in implementation four, five, and six, and details are not described herein. For example, the luminance block of node A is divided, and the chrominance block is not divided.
  • Step 5 Parse the prediction block and residual information of the CU obtained by the node A partition.
  • step 5 it is the same as step 5 in the fourth embodiment, and details are not described herein.
  • Step 6 Decode each CU to obtain the reconstructed signal of the image block corresponding to node A
  • a 4x4 luma block will be generated (for example, 64 luma pixels are divided by QT, or 128 luma pixels are divided by TT).
  • transmitting a flag indicates that the current area can only use inter mode or only intra mode
  • the luminance and chrominance are divided together, and if the node division in the current region results in a 4x4 luma block, this division is not allowed. For example, if the current node is 8x8 and is divided by HBT (or VBT), two 8x4 nodes are generated. If these nodes continue to be divided, 4x4CU will be generated, so these 8x4 nodes cannot continue to be divided.
  • Intra mode can be used, which is the same as the original implementation (luminance division, chrominance division).
  • An embodiment of the present invention proposes a block division method, which avoids the use of an intra prediction mode for chroma blocks with a small area, which is convenient for hardware pipeline processing and the implementation of a decoder. At the same time, some inter-frame predictions can be skipped. The parsing process of the syntax elements of the prediction mode, thereby reducing the coding complexity.
  • the block division method can be as follows:
  • the chrominance block of at least one child node B obtained by the node A according to the division method S described above is a small block. (Judging whether the width, height, and / or division of node A, and / or the width and height of node B meet at least one of the above conditions)
  • all the coding units in the coverage area of the node A are restricted to the intra prediction mode or the inter prediction mode.
  • the luminance block of node A continues to be divided according to the division mode S, and the chrominance block of node A is no longer divided. If all coding units in the coverage area of node A use inter prediction, the luminance block and chrominance block of node A are further divided into N coding tree nodes containing luminance blocks and chrominance blocks according to the division method S.
  • the luminance block of the node A continues to be divided according to the division method S, and the chrominance block of the node A is no longer divided.
  • the chroma transform block is the same size as the chroma code block.
  • the chroma prediction block and chroma coding block are the same size; when all coding units in the coverage area of node A use inter prediction, the chroma prediction block is divided into Sub-blocks (sub-blocks are smaller than chroma-coded blocks), and the motion vector of each sub-block is the motion vector in the luma region corresponding to the sub-block.
  • the luminance block of node A continues to be divided according to the division method S; the chrominance block of node A is no longer divided.
  • the chroma transform block corresponding to the chroma coding block is the same size as the chroma coding block
  • the chroma prediction block is the same size as the chroma coding block
  • the motion information of the chroma CB is a preset position in the luminance area corresponding to the chroma CB Sports information.
  • the disclosure combined with the described method may be equally applicable to a corresponding device or system for performing the method, and vice versa.
  • the corresponding device may include one or more units such as functional units to perform the described one or more method steps (e.g., one unit performs one or more steps Or multiple units, each of which performs one or more of the multiple steps), even if such one or more units are not explicitly described or illustrated in the drawings.
  • the corresponding method may include a step to perform the functionality of one or more units (e.g., a step performs one or more units Functionality, or multiple steps, where each performs the functionality of one or more of the multiple units), even if such one or more steps are not explicitly described or illustrated in the drawings.
  • a step performs one or more units Functionality, or multiple steps, where each performs the functionality of one or more of the multiple units
  • the features of the various exemplary embodiments and / or aspects described herein may be combined with each other, unless explicitly stated otherwise.
  • a computer-readable medium may include a computer-readable storage medium, which corresponds to a tangible medium such as a data storage medium or a communication medium including any medium that facilitates transfer of a computer program from one place to another, according to a communication protocol, for example.
  • computer-readable media generally may correspond to (1) tangible computer-readable storage media that is non-transitory, or (2) a communication medium such as a signal or carrier wave.
  • a data storage medium may be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, codes, and / or data structures used to implement the techniques described in this disclosure.
  • the computer program product may include a computer-readable medium.
  • such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, flash memory, or may be used to store instructions or data structures Any other media that requires program code and is accessible by the computer.
  • any connection is properly termed a computer-readable medium.
  • a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared, radio, and microwave is used to transmit instructions from a website, server, or other remote source
  • Coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium.
  • the computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other temporary media, but are actually directed to non-transitory tangible storage media.
  • magnetic disks and compact discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), flexible discs and Blu-ray discs, where the discs are usually magnetic The data is reproduced, while the optical disk uses a laser to reproduce the data optically. Combinations of the above should also be included within the scope of computer-readable media.
  • processors such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits , ASIC), field programmable logic array (field programmable logic arrays, FPGA) or other equivalent integrated or discrete logic circuits.
  • DSPs digital signal processors
  • ASIC application specific integrated circuits
  • FPGA field programmable logic arrays
  • processors may refer to any of the above-described structures or any other structure suitable for implementing the techniques described herein.
  • the functionality described herein may be provided within dedicated hardware and / or software modules for encoding and decoding, or incorporated in a composite codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.
  • the techniques of this disclosure may be implemented in a variety of devices or devices that include a wireless handset, an integrated circuit (IC), or a collection of ICs (eg, a chipset).
  • IC integrated circuit
  • the present disclosure describes various components, modules, or units to emphasize functional aspects of the device for performing the disclosed techniques, but does not necessarily need to be implemented by different hardware units.
  • the various units may be combined in a codec hardware unit in combination with suitable software and / or firmware, or provided by a collection of interoperable hardware units, which include as described above One or more processors.

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Abstract

本发明实施例提供一种图像的划分方法和装置。所述方法包括确定当前节点的划分方式，所述当前节点包含亮度块和色度块；根据所述当前节点的划分方式和所述当前节点的尺寸，确定所述当前节点的色度块不再划分；和当所述当前节点的色度块不再划分时，按照所述当前节点的划分方式对所述当前节点的亮度块进行划分。当所述当前节点的色度块不再划分时，该方法可以仅对所述当前节点的亮度块进行划分，从而可以提高编解码效率，降低编解码器的最大吞吐率，利于编解码器的实现。

Description

图像划分方法及装置
本申请要求于2018年8月28日提交中国国家知识产权局、申请号为201810990466.9、申请名称为“图像划分方法及装置”，2018年9月25日提交中国国家知识产权局、申请号为201811116761.8、申请名称为“图像划分方法及装置”，2019年3月11日提交中国国家知识产权局、申请号为201910183731.7、申请名称为“图像划分方法及装置”，2019年3月13日提交中国国家知识产权局、申请号为201910191131.5、申请名称为“图像划分方法及装置”，2019年3月7日提交中国国家知识产权局、申请号为201910173454.1、申请名称为“视频编码器、视频解码器及相应方法”，2019年3月21日提交中国国家知识产权局、申请号为201910219440.9、申请名称为“视频编码器、视频解码器及相应方法”，2019年7月30日提交中国国家知识产权局、申请号为201910696741.0、申请名称为“视频编码器、视频解码器及相应方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及视频编解码领域，更确切地说，涉及一种图像划分(picture partition)方法及装置。
背景技术
随着互联网科技的迅猛发展以及人们物质精神文化的日益丰富，在互联网中针对视频的应用需求尤其是针对高清视频的应用需求越来越多，而高清视频的数据量非常大，要想高清视频能在带宽有限的互联网中传输，必须首先解决的问题就是视频编解码问题。视频编解码广泛用于数字视频应用，例如广播数字电视、互联网和移动网络上的视频传播、视频聊天和视频会议等实时会话应用、DVD和蓝光光盘、视频内容采集和编辑系统以及可携式摄像机的安全应用。
视频序列的每个图片通常分割成不重叠的块集合，通常在块层级上进行编码。例如，通过空间(图片内)预测和时间(图片间)预测来产生预测块。相应地，预测模式可以包括帧内预测模式(空间预测)和帧间预测模式(时间预测)。其中，帧内预测模式集合可以包括35种不同的帧内预测模式，例如，如DC(或均值)模式和平面模式的非方向性模式；或者如H.265中定义的方向性模式；或者可以包括67种不同的帧内预测模式，例如，如DC(或均值)模式和平面模式的非方向性模式；或者如正在发展中的H.266中定义的方向性模式。帧间预测模式集合取决于可用参考图片和其它帧间预测参数，例如取决于是否使用整个参考图片或只使用参考图片的一部分。
现有的视频一般为彩色视频，除了含有亮度分量以外，还含有色度分量。因此，除了对亮度分量进行编解码，还需要对色度分量进行编解码。但是，现有技术中编解码效率比较低。
发明内容
本申请(或本公开)实施例提供图像划分的装置和方法。
第一方面，本发明实施例涉及一种图像划分的方法。所述方法由解码视频流的或编码视频流的装置执行。所述方法包括确定当前节点的划分方式，所述当前节点包含亮度块和色度块；根据所述当前节点的划分方式和所述当前节点的尺寸，确定所述当前节点的色度块不再划分；和当所述当前节点的色度块不再划分时，按照所述当前节点的划分方式对所述当前节点的亮度块进行划分。
第一方面的方法当所述当前节点的色度块不再划分时，该方法可以仅对所述当前节点的亮度块进行划分，从而可以提高编解码效率，降低编解码器的最大吞吐率，利于编解码器的实现。
第二方面，本发明实施例涉及解码视频流的装置，包含处理器和存储器。所述存储器存储指令，所述指令使得所述处理器执行根据第一方面的方法。
第三方面，本发明实施例涉及编码视频流的装置，包含处理器和存储器。所述存储器存储指令，所述指令使得所述处理器执行根据第一方面的方法。
第四方面，提出计算机可读存储介质，其上储存有指令，所述指令执行时，使得一个或多个处理器编码视频数据。所述指令使得所述一个或多个处理器执行根据第一方面任何可能实施例的方法。
第五方面，本发明实施例涉及包括程序代码的计算机程序，所述程序代码在计算机上运行时执行根据第一方面任何可能实施例的方法。
在附图及以下说明中阐述一个或多个实施例的细节。其它特征、目的和优点通过说明书、附图以及权利要求是显而易见的。
附图说明
为了更清楚地说明本申请实施例或背景技术中的技术方案，下面将对本申请实施例或背景技术中所需要使用的附图进行说明。
图1A示出用于实现本发明实施例的视频编码系统实例的框图；
图1B示出包含图2的编码器20和图3的解码器30中的任一个或两个的视频编码系统实例的框图；
图2示出用于实现本发明实施例的视频编码器实例结构的框图；
图3示出用于实现本发明实施例的视频解码器实例结构的框图；
图4绘示一种编码装置或解码装置实例的框图；
图5绘示另一种编码装置或解码装置实例的框图；
图6示出YUV格式采样网格示例；
图7A到7E示出五种不同划分类型；
图8示出四叉树和二叉树组合划分方式；
图9示出本发明实施例一的方法流程图；
图10示出本发明实施例一的步骤906的流程图；
图11示出本发明实施例三的方法流程图。
以下如果没有关于相同参考符号的具体注释，相同的参考符号是指相同或至少功能上等效的特征。
具体实施方式
视频编码通常是指处理形成视频或视频序列的图片序列。在视频编码领域，术语“图片(picture)”、“帧(frame)”或“图像(image)”可以用作同义词。本申请(或本公开)中使用的视频编码表示视频编码或视频解码。视频编码在源侧执行，通常包括处理(例如，通过压缩)原始视频图片以减少表示该视频图片所需的数据量，从而更高效地存储和/或传输。视频解码在目的地侧执行，通常包括相对于编码器作逆处理，以重构视频图片。实施例涉及的视频图片“编码”应理解为涉及视频序列的“编码”或“解码”。编码部分和解码部分的组合也称为编解码(编码和解码)。
视频序列的每个图片通常分割成不重叠的块集合，通常在块层级上进行编码。换句话说，编码器侧通常在块(也称为图像块，或视频块)层级处理亦即编码视频，例如，通过空间(图片内)预测和时间(图片间)预测来产生预测块，从当前块(当前处理或待处理的块)减去预测块以获取残差块，在变换域变换残差块并量化残差块，以减少待传输(压缩)的数据量，而解码器侧将相对于编码器的逆处理部分应用于经编码或经压缩块，以重构用于表示的当前块。另外，编码器复制解码器处理循环，使得编码器和解码器生成相同的预测(例如帧内预测和帧间预测)和/或重构，用于处理亦即编码后续块。
术语“块”可以为图片或帧的一部分。本申请对关键术语进行如下定义：
当前块：指当前正在处理的块。例如在编码中，指当前正在编码的块；在解码中，指当前正在解码的块。如果当前处理的块为色度分量块，则称为当前色度块。当前色度块对应的亮度块可以称为当前亮度块。
CTU：编码树单元(coding tree unit)，一幅图像由多个CTU构成，一个CTU通常对应于一个方形图像区域，包含这个图像区域中的亮度像素和色度像素(或者也可以只包含亮度像素，或者也可以只包含色度像素)；CTU中还包含语法元素，这些语法元素指示如何将CTU划分成至少一个编码单元(coding unit,CU)，以及解码每个编码单元得到重建图像的方法。
CU：编码单元，通常对应于一个A×B的矩形区域，包含A×B亮度像素和它对应的色度像素，A为矩形的宽，B为矩形的高，A和B可以相同也可以不同，A和B的取值通常为2的整数次幂，例如256、128、64、32、16、8、4。一个编码单元可通过解码处理解码得到一个A×B的矩形区域的重建图像，解码处理通常包括预测、反量化、反变换等处理，产生预测图像和残差，预测图像和残差叠加后得到重建图像。
以下基于图1A、图1B到3描述编码器20、解码器30和编码系统10的实施例。
图1A为绘示示例性编码系统10的概念性或示意性框图，例如，可以利用本申请(本公开)技术的视频编码系统10。视频编码系统10的编码器20(例如，视频编码器20)和解码器30(例如，视频解码器30)表示可用于根据本申请中描述的各种实例执行用于帧内预测的设备实例。如图1A中所示，编码系统10包括源设备12，用于向例如解码经编码数据13的目的地设备14提供经编码数据13，例如，经编码图片13。
源设备12包括编码器20，另外可选地，可以包括图片源16，例如图片预处理单元18的预处理单元18，以及通信接口或通信单元22。
图片源16可以包括或可以为任何类别的图片捕获设备，用于例如捕获现实世界图片，和/或任何类别的图片或评论(对于屏幕内容编码，屏幕上的一些文字也认为是待编码的图片或图像的一部分)生成设备，例如，用于生成计算机动画图片的计算机图形处理器，或用于获取和/或提供现实世界图片、计算机动画图片(例如，屏幕内容、虚拟现实(virtual reality，VR)图片)的任何类别设备，和/或其任何组合(例如，实景(augmented reality，AR)图片)。
图片可以视为具有亮度值的采样点的二维阵列或矩阵。阵列中的采样点也可以称为像素(pixel)(像素(picture element)的简称)或像素(pel)。阵列或图片在水平和垂直方向(或轴线)上的采样点数目定义图片的尺寸和/或分辨率。为了表示颜色，通常采用三个颜色分量，即图片可以表示为或包含三个采样阵列。RBG格式或颜色空间中，图片包括对应的红色、绿色及蓝色采样阵列。但是，在视频编码中，每个像素通常以亮度/色度格式或颜色空间表示，例如，YCbCr，包括Y指示的亮度分量(有时也可以用L指示)以及Cb和Cr指示的两个色度分量。亮度(简写为luma)分量Y表示亮度或灰度水平强度(例如，在灰度等级图片中两者相同)，而两个色度(简写为chroma)分量Cb和Cr表示色度或颜色信息分量。相应地，YCbCr格式的图片包括亮度采样值(Y)的亮度采样阵列，和色度值(Cb和Cr)的两个色度采样阵列。RGB格式的图片可以转换或变换为YCbCr格式，反之亦然，该过程也称为色彩变换或转换。如果图片是黑贝的，该图片可以只包括亮度采样阵列。
图片源16(例如，视频源16)可以为，例如用于捕获图片的相机，例如图片存储器的存储器，包括或存储先前捕获或产生的图片，和/或获取或接收图片的任何类别的(内部或外部)接口。相机可以为，例如，本地的或集成在源设备中的集成相机，存储器可为本地的或例如集成在源设备中的集成存储器。接口可以为，例如，从外部视频源接收图片的外部接口，外部视频源例如为外部图片捕获设备，比如相机、外部存储器或外部图片生成设备，外部图片生成设备例如为外部计算机图形处理器、计算机或服务器。接口可以为根据任何专有或标准化接口协议的任何类别的接口，例如有线或无线接口、光接口。获取图片数据17的接口可以是与通信接口22相同的接口或是通信接口22的一部分。
区别于预处理单元18和预处理单元18执行的处理，图片或图片数据17(例如，视频数据16)也可以称为原始图片或原始图片数据17。
预处理单元18用于接收(原始)图片数据17并对图片数据17执行预处理，以获取经预处理的图片19或经预处理的图片数据19。例如，预处理单元18执行的预处理可以包括整修、色彩格式转换(例如，从RGB转换为YCbCr)、调色或去噪。可以理解，预处理单元18可以是可选组件。
编码器20(例如，视频编码器20)用于接收经预处理的图片数据19并提供经编码图片 数据21(下文将进一步描述细节，例如，基于图2或图4)。在一个实例中，编码器20可以用于执行下述实施例一至三。
源设备12的通信接口22可以用于接收经编码图片数据21并传输至其它设备，例如，目的地设备14或任何其它设备，以用于存储或直接重构，或用于在对应地存储经编码数据13和/或传输经编码数据13至其它设备之前处理经编码图片数据21，其它设备例如为目的地设备14或任何其它用于解码或存储的设备。
目的地设备14包括解码器30(例如，视频解码器30)，另外亦即可选地，可以包括通信接口或通信单元28、后处理单元32和显示设备34。
目的地设备14的通信接口28用于例如，直接从源设备12或任何其它源接收经编码图片数据21或经编码数据13，任何其它源例如为存储设备，存储设备例如为经编码图片数据存储设备。
通信接口22和通信接口28可以用于藉由源设备12和目的地设备14之间的直接通信链路或藉由任何类别的网络传输或接收经编码图片数据21或经编码数据13，直接通信链路例如为直接有线或无线连接，任何类别的网络例如为有线或无线网络或其任何组合，或任何类别的私网和公网，或其任何组合。
通信接口22可以例如用于将经编码图片数据21封装成合适的格式，例如包，以在通信链路或通信网络上传输。
形成通信接口22的对应部分的通信接口28可以例如用于解封装经编码数据13，以获取经编码图片数据21。
通信接口22和通信接口28都可以配置为单向通信接口，如图1A中用于经编码图片数据13的从源设备12指向目的地设备14的箭头所指示，或配置为双向通信接口，以及可以用于例如发送和接收消息来建立连接、确认和交换任何其它与通信链路和/或例如经编码图片数据传输的数据传输有关的信息。
解码器30用于接收经编码图片数据21并提供经解码图片数据31或经解码图片31(下文将进一步描述细节，例如，基于图3或图5)。在一个实例中，解码器30可以用于执行下述实施例一至三。
目的地设备14的后处理器32用于后处理经解码图片数据31(也称为经重构图片数据)，例如，经解码图片131，以获取经后处理图片数据33，例如，经后处理图片33。后处理单元32执行的后处理可以包括，例如，色彩格式转换(例如，从YCbCr转换为RGB)、调色、整修或重采样，或任何其它处理，用于例如准备经解码图片数据31以由显示设备34显示。
目的地设备14的显示设备34用于接收经后处理图片数据33以向例如用户或观看者显示图片。显示设备34可以为或可以包括任何类别的用于呈现经重构图片的显示器，例如，集成的或外部的显示器或监视器。例如，显示器可以包括液晶显示器(liquid crystal display，LCD)、有机发光二极管(organic light emitting diode，OLED)显示器、等离子显示器、投影仪、微LED显示器、硅基液晶(liquid crystal on silicon，LCoS)、数字光处理器(digital light processor，DLP)或任何类别的其它显示器。
虽然图1A将源设备12和目的地设备14绘示为单独的设备，但设备实施例也可以同时包括源设备12和目的地设备14或同时包括两者的功能性，即源设备12或对应的功能性以及目的地设备14或对应的功能性。在此类实施例中，可以使用相同硬件和/或软件，或使用单独的硬件和/或软件，或其任何组合来实施源设备12或对应的功能性以及目的地设备14或对应的功能性。
本领域技术人员基于描述明显可知，不同单元的功能性或图1A所示的源设备12和/或目的地设备14的功能性的存在和(准确)划分可能根据实际设备和应用有所不同。
编码器20(例如，视频编码器20)和解码器30(例如，视频解码器30)都可以实施为各种合适电路中的任一个，例如，一个或多个微处理器、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)、离散逻辑、硬件或其任何组合。如果部分地以软件实施所述技术，则设备可将软件的指令存储于合适的非暂时性计算机可读存储介质中，且可使用一或多个处理器以硬件执行指令从而执行本公开的技术。前述内容(包含硬件、软件、硬件与软件的组合等)中的任一者可视为一或多个处理器。视频编码器20和视频解码器30中的每一个可以包含在一或多个编码器或解码器中，所述编码器或解码器中的任一个可以集成为对应设备中的组合编码器/解码器(编解码器)的一部分。
源设备12可称为视频编码设备或视频编码装置。目的地设备14可称为视频解码设备或视频解码装置。源设备12以及目的地设备14可以是视频编码设备或视频编码装置的实例。
源设备12和目的地设备14可以包括各种设备中的任一个，包含任何类别的手持或静止设备，例如，笔记本或膝上型计算机、移动电话、智能电话、平板或平板计算机、摄像机、台式计算机、机顶盒、电视、显示设备、数字媒体播放器、视频游戏控制台、视频流式传输设备(例如内容服务服务器或内容分发服务器)、广播接收器设备、广播发射器设备等，并可以不使用或使用任何类别的操作系统。
在一些情况下，源设备12和目的地设备14可以经装备以用于无线通信。因此，源设备12和目的地设备14可以为无线通信设备。
在一些情况下，图1A中所示视频编码系统10仅为示例，本申请的技术可以适用于不必 包含编码和解码设备之间的任何数据通信的视频编码设置(例如，视频编码或视频解码)。在其它实例中，数据可从本地存储器检索、在网络上流式传输等。视频编码设备可以对数据进行编码并且将数据存储到存储器，和/或视频解码设备可以从存储器检索数据并且对数据进行解码。在一些实例中，由并不彼此通信而是仅编码数据到存储器和/或从存储器检索数据且解码数据的设备执行编码和解码。
应理解，对于以上参考视频编码器20所描述的实例中的每一个，视频解码器30可以用于执行相反过程。关于信令语法元素，视频解码器30可以用于接收并解析这种语法元素，相应地解码相关视频数据。在一些例子中，视频编码器20可以将语法元素熵编码成经编码视频比特流。在此类实例中，视频解码器30可以解析这种语法元素，并相应地解码相关视频数据。
图1B是根据一示例性实施例的包含图2的编码器20和/或图3的解码器30的视频编码系统40的实例的说明图。系统40可以实现本申请的各种技术的组合。在所说明的实施方式中，视频编码系统40可以包含成像设备41、视频编码器20、视频解码器30(和/或藉由处理单元46的逻辑电路47实施的视频编码器)、天线42、一个或多个处理器43、一个或多个存储器44和/或显示设备45。
如图所示，成像设备41、天线42、处理单元46、逻辑电路47、视频编码器20、视频解码器30、处理器43、存储器44和/或显示设备45能够互相通信。如所论述，虽然用视频编码器20和视频解码器30绘示视频编码系统40，但在不同实例中，视频编码系统40可以只包含视频编码器20或只包含视频解码器30。
在一些实例中，如图所示，视频编码系统40可以包含天线42。例如，天线42可以用于传输或接收视频数据的经编码比特流。另外，在一些实例中，视频编码系统40可以包含显示设备45。显示设备45可以用于呈现视频数据。在一些实例中，如图所示，逻辑电路47可以通过处理单元46实施。处理单元46可以包含专用集成电路(application-specific integrated circuit，ASIC)逻辑、图形处理器、通用处理器等。视频编码系统40也可以包含可选处理器43，该可选处理器43类似地可以包含专用集成电路(application-specific integrated circuit，ASIC)逻辑、图形处理器、通用处理器等。在一些实例中，逻辑电路47可以通过硬件实施，如视频编码专用硬件等，处理器43可以通过通用软件、操作系统等实施。另外，存储器44可以是任何类型的存储器，例如易失性存储器(例如，静态随机存取存储器(Static Random Access Memory，SRAM)、动态随机存储器(Dynamic Random Access Memory，DRAM)等)或非易失性存储器(例如，闪存等)等。在非限制性实例中，存储器44可以由超速缓存内存实施。在一些实例中，逻辑电路47可以访问存储器44(例如用于实施图像缓冲器)。在其它实例中，逻辑电路47和/或处理单元46可以包含存储器(例如，缓存等)用于实施图像缓冲器等。
在一些实例中，通过逻辑电路实施的视频编码器20可以包含(例如，通过处理单元46或存储器44实施的)图像缓冲器和(例如，通过处理单元46实施的)图形处理单元。图形 处理单元可以通信耦合至图像缓冲器。图形处理单元可以包含通过逻辑电路47实施的视频编码器20，以实施参照图2和/或本文中所描述的任何其它编码器系统或子系统所论述的各种模块。逻辑电路可以用于执行本文所论述的各种操作。
视频解码器30可以以类似方式通过逻辑电路47实施，以实施参照图3的解码器30和/或本文中所描述的任何其它解码器系统或子系统所论述的各种模块。在一些实例中，逻辑电路实施的视频解码器30可以包含(通过处理单元2820或存储器44实施的)图像缓冲器和(例如，通过处理单元46实施的)图形处理单元。图形处理单元可以通信耦合至图像缓冲器。图形处理单元可以包含通过逻辑电路47实施的视频解码器30，以实施参照图3和/或本文中所描述的任何其它解码器系统或子系统所论述的各种模块。
在一些实例中，视频编码系统40的天线42可以用于接收视频数据的经编码比特流。如所论述，经编码比特流可以包含本文所论述的与编码视频帧相关的数据、指示符、索引值、模式选择数据等，例如与编码分割相关的数据(例如，变换系数或经量化变换系数，(如所论述的)可选指示符，和/或定义编码分割的数据)。视频编码系统40还可包含耦合至天线42并用于解码经编码比特流的视频解码器30。显示设备45用于呈现视频帧。
编码器&编码方法
图2示出用于实现本申请(公开)技术的视频编码器20的实例的示意性/概念性框图。在图2的实例中，视频编码器20包括残差计算单元204、变换处理单元206、量化单元208、逆量化单元210、逆变换处理单元212、重构单元214、缓冲器216、环路滤波器单元220、经解码图片缓冲器(decoded picture buffer，DPB)230、预测处理单元260和熵编码单元270。预测处理单元260可以包含帧间预测单元244、帧内预测单元254和模式选择单元262。帧间预测单元244可以包含运动估计单元和运动补偿单元(未图示)。图2所示的视频编码器20也可以称为混合型视频编码器或根据混合型视频编解码器的视频编码器。
例如，残差计算单元204、变换处理单元206、量化单元208、预测处理单元260和熵编码单元270形成编码器20的前向信号路径，而例如逆量化单元210、逆变换处理单元212、重构单元214、缓冲器216、环路滤波器220、经解码图片缓冲器(decoded picture buffer，DPB)230、预测处理单元260形成编码器的后向信号路径，其中编码器的后向信号路径对应于解码器的信号路径(参见图3中的解码器30)。
编码器20通过例如输入202，接收图片201或图片201的块203，例如，形成视频或视频序列的图片序列中的图片。图片块203也可以称为当前图片块或待编码图片块，图片201可以称为当前图片或待编码图片(尤其是在视频编码中将当前图片与其它图片区分开时，其它图片例如同一视频序列亦即也包括当前图片的视频序列中的先前经编码和/或经解码图片)。
分割
编码器20的实施例可以包括分割单元(图2中未绘示)，用于将图片201分割成多个例如块203的块，通常分割成多个不重叠的块。分割单元可以用于对视频序列中所有图片使用相同的块大小以及定义块大小的对应栅格，或用于在图片或子集或图片群组之间更改块大小，并将每个图片分割成对应的块。
在一个实例中，视频编码器20的预测处理单元260可以用于执行上述分割技术的任何组合。
如图片201，块203也是或可以视为具有亮度值(采样值)的采样点的二维阵列或矩阵，虽然其尺寸比图片201小。换句话说，块203可以包括，例如，一个采样阵列(例如黑白图片201情况下的亮度阵列)或三个采样阵列(例如，彩色图片情况下的一个亮度阵列和两个色度阵列)或依据所应用的色彩格式的任何其它数目和/或类别的阵列。块203的水平和垂直方向(或轴线)上采样点的数目定义块203的尺寸。
如图2所示的编码器20用于逐块编码图片201，例如，对每个块203执行编码和预测。
残差计算
残差计算单元204用于基于图片块203和预测块265(下文提供预测块265的其它细节)计算残差块205，例如，通过逐样本(逐像素)将图片块203的样本值减去预测块265的样本值，以在样本域中获取残差块205。
变换
变换处理单元206用于在残差块205的样本值上应用例如离散余弦变换(discrete cosine transform，DCT)或离散正弦变换(discrete sine transform，DST)的变换，以在变换域中获取变换系数207。变换系数207也可以称为变换残差系数，并在变换域中表示残差块205。
变换处理单元206可以用于应用DCT/DST的整数近似值，例如为HEVC/H.265指定的变换。与正交DCT变换相比，这种整数近似值通常由某一因子按比例缩放。为了维持经正变换和逆变换处理的残差块的范数，应用额外比例缩放因子作为变换过程的一部分。比例缩放因子通常是基于某些约束条件选择的，例如，比例缩放因子是用于移位运算的2的幂、变换系数的位深度、准确性和实施成本之间的权衡等。例如，在解码器30侧通过例如逆变换处理单元212为逆变换(以及在编码器20侧通过例如逆变换处理单元212为对应逆变换)指定具体比例缩放因子，以及相应地，可以在编码器20侧通过变换处理单元206为正变换指定对应比例缩放因子。
量化
量化单元208用于例如通过应用标量量化或向量量化来量化变换系数207，以获取经量 化变换系数209。经量化变换系数209也可以称为经量化残差系数209。量化过程可以减少与部分或全部变换系数207有关的位深度。例如，可在量化期间将n位变换系数向下舍入到m位变换系数，其中n大于m。可通过调整量化参数(quantization parameter，QP)修改量化程度。例如，对于标量量化，可以应用不同的标度来实现较细或较粗的量化。较小量化步长对应较细量化，而较大量化步长对应较粗量化。可以通过量化参数(quantization parameter，QP)指示合适的量化步长。例如，量化参数可以为合适的量化步长的预定义集合的索引。例如，较小的量化参数可以对应精细量化(较小量化步长)，较大量化参数可以对应粗糙量化(较大量化步长)，反之亦然。量化可以包含除以量化步长以及例如通过逆量化210执行的对应的量化或逆量化，或者可以包含乘以量化步长。根据例如HEVC的一些标准的实施例可以使用量化参数来确定量化步长。一般而言，可以基于量化参数使用包含除法的等式的定点近似来计算量化步长。可以引入额外比例缩放因子来进行量化和反量化，以恢复可能由于在用于量化步长和量化参数的等式的定点近似中使用的标度而修改的残差块的范数。在一个实例实施方式中，可以合并逆变换和反量化的标度。或者，可以使用自定义量化表并在例如比特流中将其从编码器通过信号发送到解码器。量化是有损操作，其中量化步长越大，损耗越大。
逆量化单元210用于在经量化系数上应用量化单元208的逆量化，以获取经反量化系数211，例如，基于或使用与量化单元208相同的量化步长，应用量化单元208应用的量化方案的逆量化方案。经反量化系数211也可以称为经反量化残差系数211，对应于变换系数207，虽然由于量化造成的损耗通常与变换系数不相同。
逆变换处理单元212用于应用变换处理单元206应用的变换的逆变换，例如，逆离散余弦变换(discrete cosine transform，DCT)或逆离散正弦变换(discrete sine transform，DST)，以在样本域中获取逆变换块213。逆变换块213也可以称为逆变换经反量化块213或逆变换残差块213。
重构单元214(例如，求和器214)用于将逆变换块213(即经重构残差块213)添加至预测块265，以在样本域中获取经重构块215，例如，将经重构残差块213的样本值与预测块265的样本值相加。
可选地，例如线缓冲器216的缓冲器单元216(或简称“缓冲器”216)用于缓冲或存储经重构块215和对应的样本值，用于例如帧内预测。在其它的实施例中，编码器可以用于使用存储在缓冲器单元216中的未经滤波的经重构块和/或对应的样本值来进行任何类别的估计和/或预测，例如帧内预测。
例如，编码器20的实施例可以经配置以使得缓冲器单元216不只用于存储用于帧内预测254的经重构块215，也用于环路滤波器单元220(在图2中未示出)，和/或，例如使得缓冲器单元216和经解码图片缓冲器单元230形成一个缓冲器。其它实施例可以用于将经滤波块221和/或来自经解码图片缓冲器230的块或样本(图2中均未示出)用作帧内预测254的输 入或基础。
环路滤波器单元220(或简称“环路滤波器”220)用于对经重构块215进行滤波以获取经滤波块221，从而顺利进行像素转变或提高视频质量。环路滤波器单元220旨在表示一个或多个环路滤波器，例如去块滤波器、样本自适应偏移(sample-adaptive offset，SAO)滤波器或其它滤波器，例如双边滤波器、自适应环路滤波器(adaptive loop filter，ALF)，或锐化或平滑滤波器，或协同滤波器。尽管环路滤波器单元220在图2中示出为环内滤波器，但在其它配置中，环路滤波器单元220可实施为环后滤波器。经滤波块221也可以称为经滤波的经重构块221。经解码图片缓冲器230可以在环路滤波器单元220对经重构编码块执行滤波操作之后存储经重构编码块。
编码器20(对应地，环路滤波器单元220)的实施例可以用于输出环路滤波器参数(例如，样本自适应偏移信息)，例如，直接输出或由熵编码单元270或任何其它熵编码单元熵编码后输出，例如使得解码器30可以接收并应用相同的环路滤波器参数用于解码。
经解码图片缓冲器(decoded picture buffer，DPB)230可以为存储参考图片数据供视频编码器20编码视频数据之用的参考图片存储器。DPB 230可由多种存储器设备中的任一个形成，例如动态随机存储器(dynamic random access memory，DRAM)(包含同步DRAM(synchronous DRAM，SDRAM)、磁阻式RAM(magnetoresistive RAM，MRAM)、电阻式RAM(resistive RAM，RRAM))或其它类型的存储器设备。可以由同一存储器设备或单独的存储器设备提供DPB 230和缓冲器216。在某一实例中，经解码图片缓冲器(decoded picture buffer，DPB)230用于存储经滤波块221。经解码图片缓冲器230可以进一步用于存储同一当前图片或例如先前经重构图片的不同图片的其它先前的经滤波块，例如先前经重构和经滤波块221，以及可以提供完整的先前经重构亦即经解码图片(和对应参考块和样本)和/或部分经重构当前图片(和对应参考块和样本)，例如用于帧间预测。在某一实例中，如果经重构块215无需环内滤波而得以重构，则经解码图片缓冲器(decoded picture buffer，DPB)230用于存储经重构块215。
预测处理单元260，也称为块预测处理单元260，用于接收或获取块203(当前图片201的当前块203)和经重构图片数据，例如来自缓冲器216的同一(当前)图片的参考样本和/或来自经解码图片缓冲器230的一个或多个先前经解码图片的参考图片数据231，以及用于处理这类数据进行预测，即提供可以为经帧间预测块245或经帧内预测块255的预测块265。
模式选择单元262可以用于选择预测模式(例如帧内或帧间预测模式)和/或对应的用作预测块265的预测块245或255，以计算残差块205和重构经重构块215。
模式选择单元262的实施例可以用于选择预测模式(例如，从预测处理单元260所支持的那些预测模式中选择)，所述预测模式提供最佳匹配或者说最小残差(最小残差意味着传输或存储中更好的压缩)，或提供最小信令开销(最小信令开销意味着传输或存储中更好的压 缩)，或同时考虑或平衡以上两者。模式选择单元262可以用于基于码率失真优化(rate distortion optimization，RDO)确定预测模式，即选择提供最小码率失真优化的预测模式，或选择相关码率失真至少满足预测模式选择标准的预测模式。
下文将详细解释编码器20的实例(例如，通过预测处理单元260)执行的预测处理和(例如，通过模式选择单元262)执行的模式选择。
如上文所述，编码器20用于从(预先确定的)预测模式集合中确定或选择最好或最优的预测模式。预测模式集合可以包括例如帧内预测模式和/或帧间预测模式。
帧内预测模式集合可以包括35种不同的帧内预测模式，或者可以包括67种不同的帧内预测模式，或者可以包括正在发展中的H.266中定义的帧内预测模式。
帧间预测模式集合取决于可用参考图片(即，例如前述存储在DBP 230中的至少部分经解码图片)和其它帧间预测参数，例如取决于是否使用整个参考图片或只使用参考图片的一部分，例如围绕当前块的区域的搜索窗区域，来搜索最佳匹配参考块，和/或例如取决于是否应用如半像素和/或四分之一像素内插的像素内插。
除了以上预测模式，也可以应用跳过模式和/或直接模式。
预测处理单元260可以进一步用于将块203分割成较小的块分区或子块，例如，通过迭代使用四叉树(quad-tree，QT)分割、二进制树(binary-tree，BT)分割或三叉树(triple-tree，TT)分割，或其任何组合，以及用于例如为块分区或子块中的每一个执行预测，其中模式选择包括选择分割的块203的树结构和选择应用于块分区或子块中的每一个的预测模式。
帧间预测单元244可以包含运动估计(motion estimation，ME)单元(图2中未示出)和运动补偿(motion compensation，MC)单元(图2中未示出)。运动估计单元用于接收或获取图片块203(当前图片201的当前图片块203)和经解码图片231，或至少一个或多个先前经重构块，例如，一个或多个其它/不同先前经解码图片231的经重构块，来进行运动估计。例如，视频序列可以包括当前图片和先前经解码图片31，或换句话说，当前图片和先前经解码图片31可以是形成视频序列的图片序列的一部分，或者形成该图片序列。
例如，编码器20可以用于从多个其它图片中的同一或不同图片的多个参考块中选择参考块，并向运动估计单元(图2中未示出)提供参考图片和/或提供参考块的位置(X、Y坐标)与当前块的位置之间的偏移(空间偏移)作为帧间预测参数。该偏移也称为运动向量(motion vector，MV)。
运动补偿单元用于获取，例如接收帧间预测参数，并基于或使用帧间预测参数执行帧间预测来获取帧间预测块245。由运动补偿单元(图2中未示出)执行的运动补偿可以包含基 于通过运动估计(可能执行对子像素精确度的内插)确定的运动/块向量取出或生成预测块。内插滤波可从已知像素样本产生额外像素样本，从而潜在地增加可用于编码图片块的候选预测块的数目。一旦接收到用于当前图片块的PU的运动向量，运动补偿单元246可以在一个参考图片列表中定位运动向量指向的预测块。运动补偿单元246还可以生成与块和视频条带相关联的语法元素，以供视频解码器30在解码视频条带的图片块时使用。
帧内预测单元254用于获取，例如接收同一图片的图片块203(当前图片块)和一个或多个先前经重构块，例如经重构相邻块，以进行帧内估计。例如，编码器20可以用于从多个帧内预测模式中选择帧内预测模式。
编码器20的实施例可以用于基于优化标准选择帧内预测模式，例如基于最小残差(例如，提供最类似于当前图片块203的预测块255的帧内预测模式)或最小码率失真。
帧内预测单元254进一步用于基于如所选择的帧内预测模式的帧内预测参数确定帧内预测块255。在任何情况下，在选择用于块的帧内预测模式之后，帧内预测单元254还用于向熵编码单元270提供帧内预测参数，即提供指示所选择的用于块的帧内预测模式的信息。在一个实例中，帧内预测单元254可以用于执行下文描述的帧内预测技术的任意组合。
熵编码单元270用于将熵编码算法或方案(例如，可变长度编码(variable length coding，VLC)方案、上下文自适应VLC(context adaptive VLC，CAVLC)方案、算术编码方案、上下文自适应二进制算术编码(context adaptive binary arithmetic coding，CABAC)、基于语法的上下文自适应二进制算术编码(syntax-based context-adaptive binary arithmetic coding，SBAC)、概率区间分割熵(probability interval partitioning entropy，PIPE)编码或其它熵编码方法或技术)应用于经量化残差系数209、帧间预测参数、帧内预测参数和/或环路滤波器参数中的单个或所有上(或不应用)，以获取可以通过输出272以例如经编码比特流21的形式输出的经编码图片数据21。可以将经编码比特流传输到视频解码器30，或将其存档稍后由视频解码器30传输或检索。熵编码单元270还可用于熵编码正被编码的当前视频条带的其它语法元素。
视频编码器20的其它结构变型可用于编码视频流。例如，基于非变换的编码器20可以在没有针对某些块或帧的变换处理单元206的情况下直接量化残差信号。在另一实施方式中，编码器20可具有组合成单个单元的量化单元208和逆量化单元210。
图3示出示例性视频解码器30，用于实现本申请的技术。视频解码器30用于接收例如由编码器20编码的经编码图片数据(例如，经编码比特流)21，以获取经解码图片231。在解码过程期间，视频解码器30从视频编码器20接收视频数据，例如表示经编码视频条带的图片块的经编码视频比特流及相关联的语法元素。
在图3的实例中，解码器30包括熵解码单元304、逆量化单元310、逆变换处理单元312、 重构单元314(例如求和器314)、缓冲器316、环路滤波器320、经解码图片缓冲器330以及预测处理单元360。预测处理单元360可以包含帧间预测单元344、帧内预测单元354和模式选择单元362。在一些实例中，视频解码器30可执行大体上与参照图2的视频编码器20描述的编码遍次互逆的解码遍次。
熵解码单元304用于对经编码图片数据21执行熵解码，以获取例如经量化系数309和/或经解码的编码参数(图3中未示出)，例如，帧间预测、帧内预测参数、环路滤波器参数和/或其它语法元素中(经解码)的任意一个或全部。熵解码单元304进一步用于将帧间预测参数、帧内预测参数和/或其它语法元素转发至预测处理单元360。视频解码器30可接收视频条带层级和/或视频块层级的语法元素。
逆量化单元310功能上可与逆量化单元110相同，逆变换处理单元312功能上可与逆变换处理单元212相同，重构单元314功能上可与重构单元214相同，缓冲器316功能上可与缓冲器216相同，环路滤波器320功能上可与环路滤波器220相同，经解码图片缓冲器330功能上可与经解码图片缓冲器230相同。
预测处理单元360可以包括帧间预测单元344和帧内预测单元354，其中帧间预测单元344功能上可以类似于帧间预测单元244，帧内预测单元354功能上可以类似于帧内预测单元254。预测处理单元360通常用于执行块预测和/或从经编码数据21获取预测块365，以及从例如熵解码单元304(显式地或隐式地)接收或获取预测相关参数和/或关于所选择的预测模式的信息。
当视频条带经编码为经帧内编码(I)条带时，预测处理单元360的帧内预测单元354用于基于信号表示的帧内预测模式及来自当前帧或图片的先前经解码块的数据来产生用于当前视频条带的图片块的预测块365。当视频帧经编码为经帧间编码(即B或P)条带时，预测处理单元360的帧间预测单元344(例如，运动补偿单元)用于基于运动向量及从熵解码单元304接收的其它语法元素生成用于当前视频条带的视频块的预测块365。对于帧间预测，可从一个参考图片列表内的一个参考图片中产生预测块。视频解码器30可基于存储于DPB 330中的参考图片，使用默认建构技术来建构参考帧列表：列表0和列表1。
预测处理单元360用于通过解析运动向量和其它语法元素，确定用于当前视频条带的视频块的预测信息，并使用预测信息产生用于正经解码的当前视频块的预测块。例如，预测处理单元360使用接收到的一些语法元素确定用于编码视频条带的视频块的预测模式(例如，帧内或帧间预测)、帧间预测条带类型(例如，B条带、P条带或GPB条带)、用于条带的参考图片列表中的一个或多个的建构信息、用于条带的每个经帧间编码视频块的运动向量、条带的每个经帧间编码视频块的帧间预测状态以及其它信息，以解码当前视频条带的视频块。
逆量化单元310可用于逆量化(即，反量化)在比特流中提供且由熵解码单元304解码的经量化变换系数。逆量化过程可包含使用由视频编码器20针对视频条带中的每一视频块所 计算的量化参数来确定应该应用的量化程度并同样确定应该应用的逆量化程度。
逆变换处理单元312用于将逆变换(例如，逆DCT、逆整数变换或概念上类似的逆变换过程)应用于变换系数，以便在像素域中产生残差块。
重构单元314(例如，求和器314)用于将逆变换块313(即经重构残差块313)添加到预测块365，以在样本域中获取经重构块315，例如通过将经重构残差块313的样本值与预测块365的样本值相加。
环路滤波器单元320(在编码循环期间或在编码循环之后)用于对经重构块315进行滤波以获取经滤波块321，从而顺利进行像素转变或提高视频质量。在一个实例中，环路滤波器单元320可以用于执行下文描述的滤波技术的任意组合。环路滤波器单元320旨在表示一个或多个环路滤波器，例如去块滤波器、样本自适应偏移(sample-adaptive offset，SAO)滤波器或其它滤波器，例如双边滤波器、自适应环路滤波器(adaptive loop filter，ALF)，或锐化或平滑滤波器，或协同滤波器。尽管环路滤波器单元320在图3中示出为环内滤波器，但在其它配置中，环路滤波器单元320可实施为环后滤波器。
随后将给定帧或图片中的经解码视频块321存储在存储用于后续运动补偿的参考图片的经解码图片缓冲器330中。
解码器30用于例如，藉由输出332输出经解码图片31，以向用户呈现或供用户查看。
视频解码器30的其它变型可用于对压缩的比特流进行解码。例如，解码器30可以在没有环路滤波器单元320的情况下生成输出视频流。例如，基于非变换的解码器30可以在没有针对某些块或帧的逆变换处理单元312的情况下直接逆量化残差信号。在另一实施方式中，视频解码器30可以具有组合成单个单元的逆量化单元310和逆变换处理单元312。
图4是根据本发明实施例的视频译码设备400(例如视频编码设备400或视频解码设备400)的结构示意图。视频译码设备400适于实施本文所描述的实施例。在一个实施例中，视频译码设备400可以是视频解码器(例如图1A的视频解码器30)或视频编码器(例如图1A的视频编码器20)。在另一个实施例中，视频译码设备400可以是上述图1A的视频解码器30或图1A的视频编码器20中的一个或多个组件。
视频译码设备400包括：用于接收数据的入口端口410和接收单元(Rx)420，用于处理数据的处理器、逻辑单元或中央处理器(CPU)430，用于传输数据的发射器单元(Tx)440和出口端口450，以及，用于存储数据的存储器460。视频译码设备400还可以包括与入口端口410、接收器单元420、发射器单元440和出口端口450耦合的光电转换组件和电光(EO)组件，用于光信号或电信号的出口或入口。
处理器430通过硬件和软件实现。处理器430可以实现为一个或多个CPU芯片、核(例如，多核处理器)、FPGA、ASIC和DSP。处理器430与入口端口410、接收器单元420、发射 器单元440、出口端口450和存储器460通信。处理器430包括译码模块470(例如编码模块470或解码模块470)。编码/解码模块470实现上述公开的实施例。例如，编码/解码模块470实现、处理或提供各种编码操作。因此，通过编码/解码模块470为视频译码设备400的功能提供了实质性的改进，并影响了视频译码设备400到不同状态的转换。或者，以存储在存储器460中并由处理器430执行的指令来实现编码/解码模块470。
存储器460包括一个或多个磁盘、磁带机和固态硬盘，可以用作溢出数据存储设备，用于在选择性地执行这些程序时存储程序，并存储在程序执行过程中读取的指令和数据。存储器460可以是易失性和/或非易失性的，可以是只读存储器(ROM)、随机存取存储器(RAM)、随机存取存储器(ternary content-addressable memory，TCAM)和/或静态随机存取存储器(SRAM)。
图5是根据一示例性实施例的可用作图1A中的源设备12和目的地设备14中的任一个或两个的装置500的简化框图。装置500可以实现本申请的技术，用于实现图像划分的装置500可以采用包含多个计算设备的计算系统的形式，或采用例如移动电话、平板计算机、膝上型计算机、笔记本电脑、台式计算机等单个计算设备的形式。
装置500中的处理器502可以为中央处理器。或者，处理器502可以为现有的或今后将研发出的能够操控或处理信息的任何其它类型的设备或多个设备。如图所示，虽然可以使用例如处理器502的单个处理器实践所揭示的实施方式，但是使用一个以上处理器可以实现速度和效率方面的优势。
在一实施方式中，装置500中的存储器504可以为只读存储器(Read Only Memory，ROM)设备或随机存取存储器(random access memory，RAM)设备。任何其他合适类型的存储设备都可以用作存储器504。存储器504可以包括代码和由处理器502使用总线512访问的数据506。存储器504可进一步包括操作系统508和应用程序510，应用程序510包含至少一个准许处理器502执行本文所描述的方法的程序。例如，应用程序510可以包括应用1到N，应用1到N进一步包括执行本文所描述的方法的视频编码应用。装置500还可包含采用从存储器514形式的附加存储器，该从存储器514例如可以为与移动计算设备一起使用的存储卡。因为视频通信会话可能含有大量信息，这些信息可以整体或部分存储在从存储器514中，并按需要加载到存储器504用于处理。
装置500还可包含一或多个输出设备，例如显示器518。在一个实例中，显示器518可以为将显示器和可操作以感测触摸输入的触敏元件组合的触敏显示器。显示器518可以通过总线512耦合于处理器502。除了显示器518还可以提供其它准许用户对装置500编程或以其它方式使用装置500的输出设备，或提供其它输出设备作为显示器518的替代方案。当输出设备是显示器或包含显示器时，显示器可以以不同方式实现，包含通过液晶显示器(liquid crystal display，LCD)、阴极射线管(cathode-ray tube，CRT)显示器、等离子显示器或发光二极管(light emitting diode，LED)显示器，如有机LED(organic LED，OLED)显示器。
装置500还可包含图像感测设备520或与其连通，图像感测设备520例如为相机或为现有的或今后将研发出的可以感测图像的任何其它图像感测设备520，所述图像例如为运行装置500的用户的图像。图像感测设备520可以放置为直接面向运行装置500的用户。在一实例中，可以配置图像感测设备520的位置和光轴以使其视野包含紧邻显示器518的区域且从该区域可见显示器518。
装置500还可包含声音感测设备522或与其连通，声音感测设备522例如为麦克风或为现有的或今后将研发出的可以感测装置500附近的声音的任何其它声音感测设备。声音感测设备522可以放置为直接面向运行装置500的用户，并可以用于接收用户在运行装置500时发出的声音，例如语音或其它发声。
虽然图5中将装置500的处理器502和存储器504绘示为集成在单个单元中，但是还可以使用其它配置。处理器502的运行可以分布在多个可直接耦合的机器中(每个机器具有一个或多个处理器)，或分布在本地区域或其它网络中。存储器504可以分布在多个机器中，例如基于网络的存储器或多个运行装置500的机器中的存储器。虽然此处只绘示单个总线，但装置500的总线512可以由多个总线形成。进一步地，从存储器514可以直接耦合至装置500的其它组件或可以通过网络访问，并且可包括单个集成单元，例如一个存储卡，或多个单元，例如多个存储卡。因此，可以以多种配置实施装置500。
如本申请前面所述，彩色视频除了含有亮度(Y)分量以外，还含有色度分量(U，V)。因此，除了对亮度分量进行编码，还需要对色度分量进行编码。按照彩色视频中亮度分量和色度分量的采样方法的不同，一般存在YUV4:4:4，YUV4:2:2，YUV4:2:0。如图6所示，其中，叉表示亮度分量采样点，圈表示色度分量采样点。
-4:4:4格式：表示色度分量没有下采样；
-4:2:2格式：表示色度分量相对于亮度分量进行2:1的水平下采样，没有竖直下采样。对于每两个U采样点或V采样点，每行都包含四个Y采样点；
-4:2:0格式：表示色度分量相对于亮度分量进行2:1的水平下采样，与2:1的竖直下采样。
视频解码器可用于根据三个不同划分结构(QT、BT和TT)利用每个深度处允许的五个不同划分类型来对视频块进行划分。划分类型包含四叉树划分(QT划分结构)、水平二叉树划分(BT划分结构)、竖直二叉树划分(BT划分结构)、水平中心-侧边三叉树划分(TT划分结构)和竖直中心-侧边三叉树划分(TT划分结构)，如图7A到7E中所示。
五个划分类型的定义如下。应注意，正方形被视为矩形的特殊情况。
四叉树(quad-tree,QT)划分：块进一步分成四个相同尺寸的矩形块。图7A示出四叉树划分的示例。基于四叉树QT的CTU划分方法，将CTU作为四叉树的根节点(root)，按照四叉树的划分方式，将CTU递归划分成若干个叶节点(leaf node)。一个节点对应于一个图像区域，节点如果不划分，则节点称为叶节点，它对应的图像区域形成一个CU；如果节点划分，则节点对应的图像区域划分成四个相同大小的区域(其长和宽各为被划分区域的一半)，每个区域对应一个节点，需要分别确定这些节点是否还会划分。一个节点是否划分由码流中这个 节点对应的划分标志位split_cu_flag指示。根节点的四叉树层级(qtDepth)为0，子节点的四叉树层级为父节点的四叉树层级+1。为表述简洁，本申请中节点的大小和形状即指节点对应的图像区域的大小和形状，即节点是图像中的一个矩形区域。Coding tree中的节点(node)划分之后得到的节点，可以称为该节点的子节点(child node)，简称为子节点。
更具体的，对64×64的CTU节点(四叉树层级为0)，根据它对应的split_cu_flag，可选择不划分，成为1个64×64的CU，或者选择划分为4个32×32的节点(四叉树层级为1)。这四个32×32的节点中的每一个节点，又可以根据它对应的split_cu_flag，选择继续划分或者不划分；如果一个32×32的节点继续划分，则产生四个16×16的节点(四叉树层级为2)。以此类推，直到所有节点都不再划分，这样一个CTU就被划分成一组CU。CU的最小尺寸(size)在SPS中标识，例如8×8为最小CU。在上述递归划分过程中，如果一个节点的尺寸等于最小CU尺寸(minimum CU size)，这个节点默认为不再划分，同时也不需要在码流中包含它的划分标志位。
当解析到一个节点为叶节点后，此叶节点为一个CU，进一步解析CU对应的编码信息(包括CU的预测模式、变换系数等信息，例如H.266中的coding_unit()语法结构体)，然后按照这些编码信息对CU进行预测、反量化、反变换、环路滤波等解码处理，产生这个CU对应的重建图像。四叉树(Quad tree,QT)结构使得CTU能够根据图像局部特点划分成合适大小的一组CU，例如平滑区域划分成较大的CU，而纹理丰富区域划分为较小的CU。
一种CTU划分成一组CU的划分方式对应于一个编码树(coding tree)。CTU应当采用何种编码树则通常通过编码器的率失真优化(rate distortion optimization,RDO)技术来确定。编码器尝试多种CTU划分方式，每一种划分方式对应于一个率失真代价(RD cost)；编码器比较各种尝试过的划分方式的RD cost，找到RD cost最小的划分方式，作为该CTU最优的划分方式，用于该CTU的实际编码。编码器尝试的各种CTU划分方式均需要符合解码器规定的划分规则，这些才能够被解码器正确识别。
竖直二叉树(binary tree,BT)划分：块竖直分成两个相同尺寸的矩形块。图7B是竖直二叉树划分的示例。
水平二叉树划分：块水平分成两个相同尺寸的矩形块。图7C是水平二叉树划分的示例。
竖直中心-侧边三叉树(triple tree,TT)划分：块竖直分成三个矩形块，使得两个侧边块尺寸相同，而中心块的尺寸是两个侧边块的总和。图7D是竖直中心-侧边三叉树划分的示例。
水平中心-侧边三叉树划分：块水平分成三个矩形块，使得两个侧边块尺寸相同，而中心块的尺寸是两个侧边块的总和。图7E是水平中心-侧边三叉树划分的示例。
图7B-图7E具体的划分方法，与图7A的描述类似，这里不再赘述。另外还可以使用QT级联BT/TT的划分方式，简称为QT-BTT，即第一级编码树上的节点只能使用QT划分成子节点，第一级编码树的叶节点为第二级编码树的根节点；第二级编码树上的节点可使用水平二分、竖直二分、水平三分、竖直三分这四种划分方式中的一种划分为子节点；第二级编码树的叶节点为编码单元。具体地，对于二叉树划分和四叉树划分采用级联的方式，可以简称为QTBT划分方式，例如CTU先按照QT划分，QT的叶节点允许继续使用BT划分，如图8所示。其中图8右图中每个端点表示一个节点，一个节点连出4根实线表示四叉树划分，一个节点连出2根虚线表示二叉树划分，划分之后得到的节点可以称为该节点的子节点，简称为子节 点。在子节点中，a到m为13个叶节点，每个叶节点表示1个CU；二叉树节点上的1表示竖直划分，0表示水平划分；一个CTU按照右图的划分，成为a到m这13个CU，如图8左图所示。QTBT划分方式中，每个CU具有QT层级(Quad-tree depth,QT depth)和BT层级(Binary tree depth,BT depth)，QT层级表示CU所属的QT叶节点CU的QT层级，BT层级表示CU所属BT叶节点的BT层级，例如图8中a和b的QT层级为1，BT层级为2；c、d、e的QT层级为1，BT层级为1；f、k、l的QT层级为2，BT层级为1；i、j的QT层级为2，BT层级为0；g、h的QT层级为2，BT层级为2；m的QT层级为1，BT层级为0。如果CTU只划分成一个CU，则此CU的QT层级为0，BT层级为0。
对于与特定深度相关联的块，编码器20确定使用哪种划分类型(包含不再进一步划分)且显式地或隐式地(例如可从预定规则推导划分类型)将确定的划分类型用信号发送到解码器30。编码器20可基于检查块使用不同划分类型的率失真成本来确定要用的划分类型。
如果对节点进行划分产生2xM的色度块时，特别是2x2、2x4、或2x8的色度块，色度编解码效率比较低，硬件解码器的处理代价较高，不利于硬件解码器的实现。当所述当前节点的色度块不再划分时，本申请实施例可以仅对当前节点的亮度块进行划分，从而可以提高编解码效率，降低解码器的最大吞吐率，利于解码器实现。具体地，本申请实施例中当一个节点使用一种划分方式划分而产生的子节点中包含边长为第一阈值的色度块(或者包含边长小于第二阈值的色度块)，则将节点包含的亮度块使用这种划分方式划分，而节点包含的色度块不再划分。通过这种方式，可以避免产生边长为第一阈值(或者边长小于第二阈值)的色度块。在一种具体的实现方式中，第一阈值可以为2，第二阈值可以为4。下面结合实施例一至三详细进行描述。本申请的实施例以视频数据格式为YUV4:2:0进行说明，对YUV4:2:2数据可采用类似的方式。
在HEVC的扩展标准SCC中采纳了帧内块复制(Intra Block Copy，IBC)的编码工具，主要用于提高屏幕内容视频的编码效率。IBC模式是一种块级的编码模式，在编码端，使用块匹配(block matching，BM)的方法为每个CU找到最佳的块矢量(block vector)或者运动矢量(motion vector)。此处的运动矢量主要用来表示当前块到参考块的位移，也称为位移矢量(displacement vector)，该参考块为当前图像内的已重建块。IBC模式可以认为是除帧内预测或者帧间预测模式之外的第三种预测模式。为了节省存储空间和减小解码器的复杂度，VTM4中的IBC模式只允许使用当前CTU的预定义区域的重建部分进行预测。
VTM中，在CU级，使用标识位来表示当前CU是否使用IBC模式，IBC模式被分为IBC AMVP模式、IBC skip模式、或者IBC merge模式。
实施例一
图9示出本发明实施例一的方法流程图900。
步骤901：判断当前节点是否需要划分，所述当前节点包含亮度块和色度块。如果当前节点不再划分成子节点，则当前节点为编码单元(coding unit,CU)，执行步骤910，解析编码单元信息；如果当前节点需要划分，则执行步骤902。
本发明实施例一可以由视频解码装置实现，具体的可以为图3-5任一所描述的装置。
本发明实施例一也可以由视频编码装置实现，具体的可以为图2，4-5任一所描述的装置。
当由视频解码装置实现时，步骤902：视频解码装置解析码流，确定当前节点的划分方式。当前节点的划分方式可以为四分(QT)、水平二分(horizontal BT)、水平三分(horizontal TT)、竖直二分(Vertical BT)、竖直三分(Vertical TT)中的至少一种，还可以是其它的划分方式，本发明实施例不做限定。当前节点的划分方式信息通常在码流中传输，通过解析码流中相应的语法元素可解析得到当前节点的划分方式。
当由视频编码装置实现时，步骤902，确定当前节点的划分方法。
步骤904：根据所述当前节点的划分方式和所述当前节点的尺寸，判断所述当前节点的色度块是否需要划分。当所述当前节点的色度块不再划分时，执行步骤906；当所述当前节点的色度块需要划分时，执行步骤908。
具体地，在一种实现方式中，可以判断当前节点按照当前节点的划分方式划分是否会产生边长为第一阈值的色度块(或者是否会产生边长小于第二阈值的色度块)。如果判断所述当前节点划分产生的子节点包含边长为第一阈值的色度块(或者包含边长小于第二阈值的色度块)，则所述当前节点的色度块不再划分。例如，第一阈值可以为2，第二阈值可以为4。
本发明实施例中边长为第一阈值的色度块即指宽为第一阈值或高为第一阈值的色度块。
在另一种实现方式中，例如：可以当以下条件1至条件5中任一种条件成立，则确定所述当前节点的色度块不再划分；否则，则确定所述当前节点的色度块需要划分。
条件1：当前节点的宽等于第二阈值的2倍且当前节点的划分方式为竖直二分。
条件2：当前节点的高等于第二阈值的2倍且当前节点的划分方式为水平二分。
条件3：当前节点的宽等于第二阈值的4倍且当前节点的划分方式为竖直三分。
条件4：当前节点的高等于第二阈值的4倍且当前节点的划分方式为水平三分。
条件5：当前节点的宽等于第二阈值的2倍且当前节点的划分方式为四分。
通常，当前节点的宽为当前节点对应亮度块的宽，当前节点的高为当前节点对应亮度块的高。在具体实现方式中，例如，第二阈值可以为4。
在第三种实现方式中，可以判断当前节点按照当前节点的划分方式划分是否会产生宽为第一阈值的色度块(或者是否会产生宽小于第二阈值的色度块)。如果判断所述当前节点划分产生的子节点包含宽为第一阈值的色度块(或者包含宽小于第二阈值的色度块)，则所述当前节点的色度块不再划分。例如，第一阈值可以为2，第二阈值可以为4。
在第四种实现方式中，可以判断当前节点按照当前节点的划分方式划分是否会产生色度像素数目少于第三阈值的色度块。如果判断所述当前节点划分产生的子节点包含色度像素数目少于第三阈值的色度块，则所述当前节点的色度块不再划分。例如，第三阈值可以为16。则色度像素数目少于16的色度块包括但不限于2x2色度块、2x4色度块、4x2色度块。第三阈值可以为8。则色度像素数目少于8的色度块包括但不限于2x2色度块。
具体地，如果以下条件1至条件2中任一种条件成立，则可以判断当前节点按照当前节点的划分方式划分会产生色度像素数目少于第三阈值的色度块；否则，可以判断当前节点按照当前节点的划分方式划分不会产生色度像素数目少于第三阈值的色度块：
条件1：当前节点的宽和高的乘积小于128且当前节点的划分方式为竖直二分或水平二分。
条件2：当前节点的宽和高的乘积小于256且当前节点的划分方式为竖直三分或水平三分或四分。
具体地，作为另一种实施方式，如果以下条件3至条件4中任一种条件成立，则可以判断当前节点按照当前节点的划分方式划分会产生色度像素数目少于第三阈值的色度块；否则，可以判断当前节点按照当前节点的划分方式划分不会产生色度像素数目少于第三阈值的色度块：
条件3：当前节点的宽和高的乘积等于64且当前节点的划分方式为竖直二分或水平二分或四分或水平三分或竖直三分。
条件4：当前节点的宽和高的乘积等于128且当前节点的划分方式为竖直三分或水平三分。
在第五种实现方式中，可以判断当前节点按照当前节点的划分方式划分是否会产生高为第一阈值的色度块(或者是否会产生高小于第二阈值的色度块)。如果判断所述当前节点划分产生的子节点包含高为第一阈值的色度块(或者包含高小于第二阈值的色度块)，则所述当前节点的色度块不再划分。例如，第一阈值可以为2，第二阈值可以为4。
步骤906：按照所述当前节点的划分方式对所述当前节点的亮度块(luma block)进行划分，得到所述当前节点的子节点(也可以称为亮度块的子节点，简称亮度节点)。每个子节点只包含亮度块。当前节点的色度块(chroma block)不再划分，成为一个只包含色度块的编码单元。
可选地，如图10所示，步骤906还可以包括步骤9062：解析所述当前节点的亮度块，获取当前节点的亮度块中各子区域的预测信息和残差信息,其中每个子区域与一个子节点对应。
具体地，步骤9062可采用以下任一种方法实现：
方法一：各亮度块的子节点默认不再划分(即各亮度节点均为编码单元，一个亮度块的子节点对应一个只包含亮度块的编码单元)，对各亮度块的子节点依次解析编码单元数据，得到各亮度块的预测信息和残差信息。一个亮度节点的亮度块是当前节点的亮度块中一个子区域，各亮度节点的亮度块构成了当前节点的亮度块。或者；
方法二：对各亮度块的子节点依次进行判断是否需要继续划分，当需要继续划分的时候，解析它们的划分方式和相应的编码单元数据。更具体的，如果一个亮度节点不再划分，则解析它对应的编码单元数据，获得此亮度节点的亮度块对应的预测信息和残差信息；如果一个亮度节点继续划分，则对此亮度节点的子节点(需要说明的是，该子节点仍只包含亮度块)继续进行判断是否需要划分，直到确定完当前节点的亮度块中各子区域的预测信息和残差信息。
所述预测信息包括但不限于：预测模式(指示帧内预测或帧间预测模式)、帧内预测模式，和/或运动信息等。亮度块的帧内预测模式可以为平面模式(Planar Mode)、直流模式(DC Mode)、角度模式(angular Mode)、色度导出模式(chroma derived mode，DM)之一；运动信息可包括预测方向(前向、后向或双向)、参考帧索引(reference index)、和/或运动矢量(motion vector)等信息。
所述残差信息包括：编码块标志位(coded block flag，cbf)、变换系数、和/或变换类 型(例如DCT-2,DST-7,DCT-8)等。
可选地，如图10所示，步骤906还可以包括步骤9064：获取该色度块的预测信息和/或残差信息。
具体地，步骤9064可以包括步骤90642和步骤90644。步骤90642可以为步骤90642A或步骤90642B。
步骤90642A具体包括：
获取当前节点的亮度块中预设位置的预测模式，作为当前节点的色度块的预测模式。当前节点的亮度块的左上角位置可以表示为(x0,y0)，大小为WxH，则预设位置可以包括但不限于亮度块的左上角、右下角(x0+W-1,y0+H-1)、中心(x0+W/2,y0+H/2)、(x0+W/2，0)、(0，y0+H/2)等。所述预测模式指示使用帧内预测还是帧间预测对预设位置的像素进行预测，例如HEVC中的pred_mode_flag语法元素指示的信息。例如，VTM中，可以根据语法元素pred_mode_ibc_flag指示的信息来确定预设位置的预测模式是否为IBC模式。
如果预设位置的预测模式为帧间预测，则使用以下方法之一确定色度的预测模式：
方法一：色度块使用帧间预测，获取预设位置的运动信息作为色度块的运动信息。
方法二：色度块使用帧间预测，将色度块划分为色度预测子块(色度预测子块大小例如宽为2个色度像素、高为2个色度像素)，色度预测子块的运动信息采用如下方式获得：
如果色度预测子块对应的亮度图像位置的亮度块采用帧间预测，则将色度预测子块对应的亮度图像位置的运动信息作为色度预测子块的运动信息；否则，获取预设位置的运动信息作为色度预测子块的运动信息。
对于YUV4:2:0图像，色度预测子块在色度图像中的坐标记为(xC,yC)，则色度预测子块对应的亮度图像位置的坐标为(xC<<1,yC<<1)。
方法三：解析pred_mode_flag标志位,确定色度块使用帧内预测还是帧间预测；如果色度块使用帧内预测，从码流中解析一个帧内预测模式，作为色度块的帧内预测模式；如果色度块使用帧间预测，则获取预设位置的运动信息作为色度块的运动信息。
方法四：解析pred_mode_flag标志位,确定色度块使用帧内预测还是帧间预测；如果色度块使用帧内预测，从码流中解析一个帧内预测模式，作为色度块的帧内预测模式，其中帧内预测模式可以为线性模型模式和DM模式中的一种，DM模式对应的亮度帧内预测模式设置为平面模式；如果色度块使用帧间预测，则将色度块划分为色度预测子块，色度预测子块的运动信息采用如下方式获得：
如果色度预测子块对应的亮度图像位置的亮度块采用帧间预测，则将色度预测子块对应的亮度图像位置的运动信息作为色度预测子块的运动信息；否则，获取预设位置的运动信息作为色度预测子块的运动信息。
其中，解析pred_mode_flag标志位时采用的上下文模型为预设的模型，如模型编号为2。
如果预设位置的预测模式为帧内预测，则色度块使用帧内预测，从码流中解析一个帧内预测模式，作为色度块的帧内预测模式。或者直接确定色度块的帧内预测模式为直流模式、平面模式、角度模式、线性模型模式或者DM模式中的一种。
如果预设位置的预测模式为IBC模式，则色度块使用IBC模式进行预测，获取预设位置的位移矢量(displacement vector)信息作为色度块的位移矢量信息。或者，
如果预设位置的预测模式为IBC模式，根据标志位pred_mode_ibc_flag来确定色度块的 预测模式：
1)如果pred_mode_ibc_flag为1，则色度块使用IBC模式；更具体的，色度块的IBC预测方法可使用VTM4.0中的方法，即将色度块划分为2x2的子块，每个子块的位移矢量等于子块对应的亮度区域的位移矢量。
2)如果pred_mode_ibc_flag为0，则色度块使用帧内预测模式或者帧间预测模式。
当使用帧内预测模式时，从码流中解析语法元素确定色度的帧内预测模式。或者，直接确定色度块的帧内预测模式为色度的帧内预测模式集合中的一种，所述色度帧内预测模式集合为：直流模式、平面模式、角度模式、线性模型、DM模式。
当使用帧间预测模式时，可以获取预设位置的运动信息作为色度块的运动信息。
需要说明的是，当码流中不存在pred_mode_ibc_flag时，如果当前节点所在的图像类型是I帧/I条带，且允许使用IBC模式，则默认pred_mode_ibc_flag为1，即色度块默认使用IBC模式；如果所在的图像类型是P/B帧/条带，默认pred_mode_ibc_flag为0。
其中，VTM中可以根据语法元素pred_mode_ibc_flag指示的信息来确定预设位置的预测模式是否为IBC模式。例如，pred_mode_ibc_flag为1表示使用IBC预测模式，为0表示不使用IBC模式。当码流中不出现pred_mode_ibc_flag时，如果在I帧/I条带中，pred_mode_ibc_flag的值与sps_ibc_enabled_flag的值相等，如果在P帧/条带，或者B帧/条带中，pred_mode_ibc_flag为0。其中，sps_ibc_enabled_flag为1表示在当前图像的解码过程中允许当前图像作为参考图像，sps_ibc_enabled_flag为0表示在当前图像的解码过程中不允许当前图像作为参考图像。
色度块的帧内预测模式可以为直流模式、平面模式、角度模式、线性模型(cross-component linear model，CCLM)模式、色度导出模式(chroma derived mode，DM)之一。如VTM中的直流模式、平面模式、角度模式、线性模型模式、色度导出模式。
步骤90642B具体包括：
获取当前节点的多个亮度块中预测模式，使用以下方法确定当前节点对应的色度块的预测模式。
如果多个亮度块都是帧内预测，则色度块使用帧内预测，从码流中解析一个帧内预测模式，作为色度块的帧内预测模式。
如果多个亮度块都是帧间预测，则使用以下方法之一确定色度的预测模式：
方法一：色度块使用帧间预测，获取预设位置的运动信息作为色度块的运动信息。所述预设位置与实施例一中的含义相同。
方法二：解析pred_mode_flag标志位,确定色度块使用帧内预测还是帧间预测；如果色度块使用帧内预测，从码流中解析一个帧内预测模式，作为色度块的帧内预测模式；如果色度块使用帧间预测，则获取预设位置的运动信息作为色度块的运动信息。
如果多个亮度块中包含帧间预测和帧内预测，可使用以下方式中的一种来确定色度块的模式信息：
1)如果预设位置的预测模式为帧间预测，则色度块使用帧间预测，获取预设位置的运动信息作为色度块的运动信息。
2)如果预设位置的预测模式为帧内预测，则色度块使用帧内预测，从码流中解析一个帧内预测模式，作为色度块的帧内预测模式。或者直接确定色度块的帧内预测模式为直流模式、平面模式、角度模式、线性模型模式或者DM模式中的一种。
3)如果预设位置的预测模式为IBC模式，则色度块使用IBC模式进行预测，获取预设位置的位移矢量信息作为色度块的位移矢量信息。
4)直接指定色度的预测模式为模式集合中的一种，所述模式集合为AMVP模式、IBC模式、跳过模式、直流模式、平面模式、角度模式、线性模型模式和DM模式。
步骤90644：解析色度块的残差信息。色度块的残差包含在一个变换单元中。变换类型可默认为DCT-2变换。
步骤908：将当前节点划分成子节点，每个子节点均包含亮度块和色度块。对每个子节点执行步骤901，继续解析子节点的划分方式，判断各子节点(也称为节点)是否还需要划分。
获得亮度块的子区域划分方式和各子区域的预测信息和残差信息后，可根据各子区域相应的预测模式对各子区域执行帧间预测处理或帧内预测处理，得到各子区域的帧间预测图像或帧内预测图像。再根据各子区域的残差信息，将变换系数经过反量化和反变换处理得到残差图像，并叠加到对应子区域的预测图像上，产生亮度块的重建图像。
获得色度块的预测信息和残差信息后，可根据色度块的预测模式对色度块执行帧间预测处理或帧内预测处理，得到色度块的帧间预测图像或帧内预测图像。再根据色度块的残差信息，将变换系数经过反量化和反变换处理得到残差图像，并叠加到色度块的预测图像上，产生色度块的重建图像。
本发明实施例一当所述当前节点的色度块不再划分时，该方法可以仅对所述当前节点的亮度块进行划分，从而可以提高编解码效率，降低解码器的最大吞吐率，利于解码器实现。
实施例二
与实施例一相比，步骤9062增加如下限制条件：各亮度节点(即各亮度块的子节点)使用相同的预测模式，即各亮度节点均使用帧内预测或均使用帧间预测。其他步骤与实施例一类似，不再赘述。
各亮度节点使用相同的预测模式可采用以下任一种方法：
方法一：如果当前帧为I帧，则当前节点的各子节点均默认使用帧内预测；如果当前帧为P帧或B帧，对第一个进行解析处理的节点(可以简称为第一个子节点)解析获得它的预测模式，其余各子节点(简称亮度节点)的预测模式默认为第一个进行解析处理的节点的预测模式。或者
方法二：如果当前帧为I帧，则当前节点的各子节点均默认使用帧内预测；如果当前帧为P帧或B帧，则当前节点的各子节点均默认使用帧间预测。
实施例三
图11示出本发明实施例三的方法流程图1100。实施例三与实施例一类似，除了步骤1104。步骤1104：根据所述当前节点的划分方式，所述当前节点的尺寸以及所述当前节点的第一个 进行解析处理的节点(可以简称为第一个子节点)的预测模式，判断所述当前节点的色度块是否划分，所述第一个子节点只包含亮度块。所述当前节点的多个子节点使用相同的预测模式，其中每个子节点只包含亮度块。
至于先判断所述当前节点的划分方式和所述当前节点的尺寸，还是先判断所述第一个子节点的预测模式，本发明实施例不做限定。
实施例三在实施例一或者二的基础上，结合当前节点的第一个子节点的预测模式，决定当前节点色度块的划分方式和相应的预测信息、残差信息解析方式。
在一种实施方式中，根据所述当前节点的划分方式和所述当前节点的尺寸，确定划分所述当前节点产生的子节点包含边长等于第一阈值或者边长小于第二阈值的色度块，且所述第一个子节点的预测模式为帧内预测，则所述当前节点的色度块不再进行划分。与实施例一类似，例如，第一阈值可以为2，第二阈值可以为4。
本发明实施例中边长为第一阈值的色度块即指宽为第一阈值或高为第一阈值的色度块。
在另一种实施方式中，当所述第一个子节点的预测模式为帧内预测，并且当以下条件1至条件5中任一种条件成立：
条件1：当前节点的宽等于第二阈值的2倍且当前节点的划分方式为竖直二分；或
条件2：当前节点的高等于第二阈值的2倍且当前节点的划分方式为水平二分；或
条件3：当前节点的宽等于第二阈值的4倍且当前节点的划分方式为竖直三分；或
条件4：当前节点的高等于第二阈值的4倍且当前节点的划分方式为水平三分；或
条件5：当前节点的宽等于第二阈值的2倍且当前节点的划分方式为四分，则所述当前节点的色度块不再进行划分。
通常，当前节点的宽为当前节点对应亮度块的宽，当前节点的高为当前节点对应亮度块的高。在具体实现方式中，例如，第二阈值可以为4。
当所述第一个子节点的预测模式为帧内预测，与第一实施例类似，在第三种实现方式中，可以判断当前节点按照当前节点的划分方式划分是否会产生宽为第一阈值的色度块(或者是否会产生宽小于第二阈值的色度块)。如果判断所述当前节点划分产生的子节点包含宽为第一阈值的色度块(或者包含宽小于第二阈值的色度块)，且所述第一个子节点的预测模式为帧内预测，则所述当前节点的色度块不再划分。例如，第一阈值可以为2，第二阈值可以为4。
当所述第一个子节点的预测模式为帧内预测，与第一实施例类似，在第四种实现方式中，可以判断当前节点按照当前节点的划分方式划分是否会产生色度像素数目少于第三阈值的色度块。如果判断所述当前节点划分产生的子节点包含色度像素数目少于第三阈值的色度块，且所述第一个子节点的预测模式为帧内预测，则所述当前节点的色度块不再划分。例如，第三阈值可以为16。则色度像素数目少于16的色度块包括但不限于2x2色度块、2x4色度块、4x2色度块。第三阈值可以为8。则色度像素数目少于8的色度块包括但不限于2x2色度块。
具体地，如果以下条件1至条件2中任一种条件成立，则可以判断当前节点按照当前节点的划分方式划分会产生色度像素数目少于第三阈值的色度块；否则，可以判断当前节点按照当前节点的划分方式划分不会产生色度像素数目少于第三阈值的色度块：
条件1：当前节点的宽和高的乘积小于128且当前节点的划分方式为竖直二分或水平二 分。
条件2：当前节点的宽和高的乘积小于256且当前节点的划分方式为竖直三分或水平三分或四分。
具体地，作为另一种实施方式，如果以下条件3至条件4中任一种条件成立，则可以判断当前节点按照当前节点的划分方式划分会产生色度像素数目少于第三阈值的色度块；否则，可以判断当前节点按照当前节点的划分方式划分不会产生色度像素数目少于第三阈值的色度块：
条件3：当前节点的宽和高的乘积等于64且当前节点的划分方式为竖直二分或水平二分或四分或水平三分或竖直三分。
条件4：当前节点的宽和高的乘积等于128且当前节点的划分方式为竖直三分或水平三分。
当所述第一个子节点的预测模式为帧内预测，与第一实施例类似，在第五种实现方式中，可以判断当前节点按照当前节点的划分方式划分是否会产生高为第一阈值的色度块(或者是否会产生高小于第二阈值的色度块)。如果判断所述当前节点划分产生的子节点包含高为第一阈值的色度块(或者包含高小于第二阈值的色度块)，且所述第一个子节点的预测模式为帧内预测，则所述当前节点的色度块不再划分。例如，第一阈值可以为2，第二阈值可以为4。
如果当前节点的色度块不再划分，则当前节点的色度块成为一个只包含色度块的编码单元。方法1100还可以包括，获取色度块的预测信息和/或残差信息。
在另一种实施方式中，根据所述当前节点的划分方式和所述当前节点的尺寸，确定划分所述当前节点产生的子节点包含边长小于阈值的色度块，如果所述第一个子节点的预测模式为帧间预测，则所述当前节点的色度块按照所述当前节点的划分方式划分。可选地，根据所述当前节点的子节点的运动信息，确定色度块的对应子节点的运动信息。比如，当前节点的色度块的子节点的运动信息可以设置为对应亮度节点的运动信息(即不需要从码流中解析色度块各子节点的运动信息)。对色度块的子节点，分别解析残差信息，获取色度块各子节点的残差信息。
当所述第一个子节点的预测模式为帧间预测，并且如下条件任一成立时：
条件1：当前节点的宽等于第二阈值的2倍且当前节点的划分方式为竖直二分；或
条件2：当前节点的高等于第二阈值的2倍且当前节点的划分方式为水平二分；或
条件3：当前节点的宽等于第二阈值的4倍且当前节点的划分方式为竖直三分；或
条件4：当前节点的高等于第二阈值的4倍且当前节点的划分方式为水平三分；或
条件5：当前节点的宽等于第二阈值的2倍且当前节点的划分方式为四分，则所述当前节点的色度块仍需要进行划分。
通常，当前节点的宽为当前节点对应亮度块的宽，当前节点的高为当前节点对应亮度块的高。在具体实现方式中，例如，第二阈值可以为4。
实施例三还可以根据亮度节点的预测模式，决定色度块的划分方式和相应的预测信息、残差信息解析方式，具有更强的灵活性。而且当亮度节点的预测模式为帧内预测时，当前节点的色度块不再划分，从而可以提高色度编解码效率，降低解码器的最大吞吐率，利于解码器实现。
CU级的部分语法结构可以如表1所示，如果当前节点不再划分为子节点，则当前节点为编码单元，按照以下的语法结构解析编码单元的预测块。
其中，skip_flag为跳过模式的标志，值为1表示当前CU使用跳过模式，值为0表示当前CU不使用跳过模式。
merge_flag为直接模式标志，值为1表示当前CU使用融合模式；值为0表示不使用融合模式。
cu_pred_mode为编码单元预测模式标志，值为1表示当前预测单元使用帧内预测模式；值为0表示当前预测单元使用普通inter预测模式。
表1
Figure PCTCN2019103094-appb-000001
CU级的部分语法解析也可以如表2所示，表2仅为一种示例，其中与表1中的skip_flag含义相同，pred_mode_flag含义与表1中cu_pred_mode含义相同。
其中，cu_skip_flag为跳过模式的标志，值为1表示当前CU使用跳过模式，值为0表示当前CU不使用跳过模式。
merge_flag为直接模式标志，值为1表示当前CU使用融合模式；值为0表示不使用融合模式。
pred_mode_flag为编码单元预测模式标志，值为1表示当前预测单元使用帧内预测模式；值为0表示当前预测单元使用普通inter预测模式。如果pred_mode_flag为1，CuPredMode[x0][y0]为CuPredMode[x0][y0]为MODE_INTRA；如果pred_mode_flag为0，CuPredMode[x0][y0]为MODE_INTER。
表2
Figure PCTCN2019103094-appb-000002
一个8xM(或Mx8)大小的节点使用竖直二分(或水平二分)划分后会产生两个4xM(或Mx4)大小的子节点；类似的，一个16xM(或Mx16)大小的节点使用垂直扩展四分(或水平扩展四分)划分后会产生四个4xM(或Mx4)大小的子节点和一个8xN(或Nx8)大小的子节点。类似的，一个16xM(或Mx16)大小的节点使用竖直三分(或水平三分)划分后会产生两个4xM(或Mx4)大小的子节点和一个8xM(或Nx8)大小的子节点。对于YUV4:2:0的数据格式，色度分量的分辨率为亮度分量的1/2，即一个4xM的节点包含了一个4xM的亮度块和两个2x(M/2)的色度块。对硬件解码器而言，小块(特别是2x2、2x4、2x8)的处理代价较高。然而，该划分方式会产生2x2、2x4等小块，不利于硬件解码器的实现。对硬件解码器而言，小块的处理复杂度较高，具体包括以下3个方面。
1)帧内预测问题：硬件设计中为了提高处理速度，帧内预测通常一次同时处理16个像素，而2x2、2x4、4x2等小块包含少于16个像素，降低了帧内预测的处理性能。
2)系数编码问题：HEVC中变换系数编码基于包含16个系数的系数组(coefficient group，CG)，而2x2、2x4、4x2的小块包含了4个或8个变换系数，这导致需要增加包含4个系数和8个系数的系数组来支持这些小块的系数编码，因此增加了实现复杂度。
3)帧间预测问题：小块的帧间预测对数据带宽要求较高，也会影响解码的处理速度。
当一个节点使用一种划分方式继续划分而产生的子节点中有一个子节点包含了边长为2的色度块，则将子节点包含的亮度块使用这种划分继续划分，而子节点的包含的色度块不再划分。通过这种方式，可以避免产生边长为2的色度块，降低解码器的最大吞吐率，利于解码器实现。同时提出根据亮度块预测模式确定色度块预测模式的方法，有效提升了编码效率。
本发明提供的方法可以应用于前述实施例的视频编解码器。
实施例四
涉及一种视频解码中的块划分方式。本实施例中的视频数据格式为YUV4:2:0格式。对YUV4:2:2数据可采用类似的方式。
步骤1：解析节点A的划分方式S，如果节点A继续划分，则执行步骤2；如果当前节点不再划分成子节点，则当前节点对应一个编码单元，解析编码单元信息；
节点A的划分方式可以是四叉树划分、竖直二分、水平二分、竖直三分、水平三分中的至少一种，还可以是其它的划分方式，本发明不做限定。当前节点的划分方式信息可以在码流中传输，通过解析码流中相应的语法元素可解析得到当前节点的划分方式。当前节点的划分方式也可以基于预设的规则确定，本发明不做限定。
步骤2：判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的色度块为小块(判断节点A的宽、高，和/或划分方式，和/或节点B的宽和高是否满足所述条件中的至少一个)。如果节点A划分得到的子节点中至少一个子节点B的色度块为小块，则执行步骤3至步骤6
具体的，节点A的至少一个子节点B的色度块为小块的判断方法可使用以下一种。
1)如果节点A的至少一个子节点B的色度块为2x2、2x4、或4x2大小，则节点A的至少一个子节点B的色度块为小块。
2)如果节点A的至少一个子节点B的色度块的宽或高为2，则节点A的至少一个子节点B的色度块为小块。
3)如果节点A包含128个亮度像素且节点A使用三叉树划分，或者如果节点A包含64个亮度像素且节点A使用二叉树划分或者四叉树划分或者三叉树划分，则节点A的至少一个子节点B的色度块为小块。
4)如果节点A包含256个亮度像素且节点使用三叉树划分或者四叉树划分，或者如果节点A包含128个亮度像素且节点使用二叉树划分，则节点A的至少一个子节点B的色度块为小块。
5)如果节点A包含N1个亮度像素且节点A使用三叉树划分，N1为64、128或者256。
6)如果节点A包含N2个亮度像素且节点A使用四叉树划分，N2为64或者256。
7)如果节点A包含N3个亮度像素且节点A使用二叉树划分，N3为64、128或者256。
需要说明的是，节点A包含128个亮度像素点也可以描述为当前节点的面积为128，或者节点A的宽和高的乘积为128，在此不作赘述。
步骤3：限制节点A覆盖区域内所有的编码单元均使用帧内预测或均使用帧间预测。其中，均使用帧内或者帧间预测，可以实现硬件对小块的并行处理，提高了编解码性能。
节点A覆盖区域内所有编码单元均使用帧内预测或均使用帧间预测可通过以下的一种方法确定。
方法一：根据语法表中的标志位来确定。
如果节点A按照划分方式S划分后得到至少一个子节点B的色度块为小块(且节点A的色度块不为小块)，则从码流中解析标志位cons_pred_mode_flag；其中，cons_pred_mode_flag为0表示节点A覆盖区域的编码单元均使用帧间预测，cons_pred_mode_flag为1表示节点A覆盖区域的编码单元均使用帧内预测。cons_pred_mode_flag可以为块划分过程中需要解析的语法元素，当解析该语法元素时，则节点A覆盖区域的编码单元的cu_pred_mode可以不再解析，其值为与cons_pred_mode_flag的值对应的默认值。
需要说明的是，如果节点A的子节点只能使用帧内预测模式，例如节点A在帧内图像中 (即节点A所在的图像类型为Intra型或I型)，或者节点A在帧内图像中且序列不使用IBC技术，则cons_pred_mode_flag默认为1，不出现在码流中。其中，IBC技术可以属于帧间预测，也可以属于帧内预测。
方法二：由节点A区域中第一个节点的预测模式确定。
解析节点A区域中第一个编码单元B0的预测模式(第一个编码单元B0的预测模式不作限制)，如果B0的预测模式为帧内预测，则节点A覆盖区域内所有编码单元均使用帧内预测；如果B0的预测模式为帧间预测，则节点A区域盖区域内所有编码单元均使用帧间预测。
步骤4：根据节点A覆盖区域的编码单元使用的预测模式，决定节点A的色度块和亮度块的划分方式。
如果节点A覆盖区域的编码单元均使用帧内预测模式，则对节点A的亮度块按照所述的划分方式S进行划分，得到N个亮度编码树节点；对节点A的色度块不划分，对应一个色度编码块(简称为色度CB)。其中，N个亮度编码树节点可以限制为不再继续划分，或者不做此限制。如果亮度子节点继续划分，则解析其划分方式进行递归划分，当亮度编码树节点不再划分时，它对应一个亮度编码块(简称为亮度CB)。其中，色度CB对应的色度变换块和色度编码块相同大小，色度预测块和色度编码块相同大小。
如果节点A覆盖区域的编码单元均使用帧间预测模式，则将节点A的亮度块和色度块按照划分方式S继续划分为N个包含亮度块和色度块的编码树节点，这N个编码树节点可继续划分或不划分，不划分时对应于包含亮度块和色度块的编码单元。
步骤5：解析节点A划分得到的CU的预测块和残差信息。
所述预测块包括：预测模式(指示帧内预测或非帧内预测模式)、帧内预测模式、帧间预测模式、运动信息等。运动信息可包括预测方向(前向、后向或双向)、参考帧索引(reference index)、运动矢量(motion vector)等信息。
所述残差信息包括：编码块标志位(coded block flag，cbf)、变换系数、变换类型(例如DCT-2,DST-7,DCT-8)等。变换类型可默认为DCT-2变换。
如果节点A划分得到的各CU限制只能使用帧内预测，则节点A划分得到的亮度CB的预测块解析包括将skip_flag、merge_flag、cu_pred_mode分别默认为0、0和1(即skip_flag、merge_flag、cu_pred_mode均不出现在码流中)，或者skip_flag、cu_pred_mode分别默认为0和1(即skip_flag、cu_pred_mode均不出现在码流中)将解析亮度CB的帧内预测模式信息；节点A划分得到的色度CB的预测块解析包括解析色度CB的帧内预测模式。色度CB的帧内预测模式的解析方法可以是：1)从码流中解析语法元素得到；2)直接设定为色度帧内预测模式集合中的一种，例如线性模型模式、DM模式(chroma derived mode，DM)和IBC模式等中的一种。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的CU的预测模式解析包括解析skip_flag或/和merge_flag，将cu_pred_mode默认为0，解析帧间预测块，如融合索引(merge index)、帧间预测方向(inter dir)，参考帧索引(reference index)、运动矢量预测值索引(motion vector predictor index)和运动矢量差分量(motion vector difference)
其中，skip_flag为跳过模式的标志，值为1表示当前CU使用跳过模式，值为0表示当前CU不使用跳过模式。merge_flag为融合模式标志，值为1表示当前CU使用融合模式；值为0表示不使用融合模式。cu_pred_mode为编码单元预测模式标志，值为1表示当前预测单元使用帧内预测；值为0表示当前预测单元使用普通帧间预测(在码流中标识帧间预测方向、参考帧索引、运动矢量预测值索引、运动矢量差分量等信息)。
需要说明的是，本实施例中所述帧内预测模式为使用编码块所在图像的空域参考像素产生编码块的预测值的预测模式，如直流模式(direct current mode,DC mode)，平面模式(Planar mode)，角度模式(angular mode)，还可能包含模版匹配模式(template matching mode)，IBC模式。
所述帧间预测模式为使用编码块的参考图像中的时域参考像素产生编码块的预测值的预测模式，如跳过模式(Skip mode)，融合模式(Merge mode)，AMVP(advanced motion vector prediction)模式或称普通Inter模式，IBC模式等。
步骤6：解码各CU，得到节点A对应的图像块的重建信号
例如，由各CU的预测块对各CU执行帧间预测处理或帧内预测处理，得到各CU的帧间预测图像或帧内预测图像。再根据各CU的残差信息，将变换系数经过反量化和反变换处理得到残差图像，并叠加到对应区域的预测图像上，产生重建图像。
通过实施例四的划分方式，将不会产生使用帧内预测的色度小块，从而解决了小块帧内预测问题。
实施例五
本实施例的步骤1、步骤2、步骤3、步骤6与实施例四相同。
步骤4：决定节点A的色度块和亮度块的划分方式。
节点A的亮度块按照划分方式S继续划分，产生N个亮度编码树节点。节点A的色度块不再划分，对应一个色度编码块(色度CB)。色度CB对应的色度变换块和色度编码块相同大小。[注：相比实施例四，本实施例中，不管限制的是帧间还是帧内预测模式，色度块总是不划分，亮度块总是按照划分方式S划分，与节点A覆盖区域的预测模式无关]。
步骤5：解析节点A划分得到的CU的预测块和残差信息。
如果节点A划分得到的各CU限制只能使用帧内预测，处理与实施例四相同。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的亮度CB的预测块解析包括解析skip_flag或/和merge_flag，将cu_pred_mode默认为0，解析帧间预测块，如融合索引(merge index)、帧间预测方向(inter dir)，参考帧索引(reference index)、运动矢量预测值索引(motion vector predictor index)和运动矢量差分量(motion vector difference)。由解析得到的帧间预测块，导出亮度CB中各4x4子块的运动信息。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的色度CB的预测块无需解析，将色度CB划分为2x2色度子块(该划分方式可以为划分方式S)，各2x2色度子块的运动信息为各2x2色度子块对应的4x4亮度区域的运动信息。
通过实施例五的划分方式，将不会产生使用帧内预测的色度小块，也不会产生小于16个像素的变换块，因此实施例五解决上述帧内预测问题和系数编码问题。
实施例六
本实施例的步骤1、步骤2、步骤3、步骤4、步骤6与实施例五相同。
步骤5：解析节点A划分得到的CU的预测块和残差信息。
如果节点A划分得到的各CU限制只能使用帧内预测，处理与实施例五相同。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的亮度CB的预测块解析与实施例五相同。
如果节点A划分得到的各CU限制只能使用帧间预测，则节点A划分得到的色度CB的预测块无需解析，色度预测块与色度编码块大小相同，色度CB的运动信息为色度CB对应的亮度区域中某个预设位置的运动信息(如亮度区域的中心、右下角或左上角等)。
通过实施例六的划分方式，将不会产生使用帧内预测的色度小块，也不会产生小块变换块，也不会产生使用帧间预测的色度小块。
实施例七
步骤1：与实施例四的步骤1相同
步骤2：判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的亮度块为4x4的亮度块(判断节点A的宽、高，和/或划分方式，和/或节点B的宽和高是否满足所述情况一中的条件中的至少一个)。
如果节点A的尺寸(宽、高)，和/或划分方式S满足情况一中的至少一个条件，则限制节点A覆盖区域内所有的编码单元均使用帧内预测。否则，判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的色度块为小块(判断节点A的尺寸，和/或划分方式S，和/或节点B的宽和高是否满足情况二中的至少一个条件，则执行步骤3至步骤6。
具体的，节点A的至少一个子节点B的色度块为小块的判断方法分为以下两种情况。
情况一：
满足以下预设条件一中的一个或者多个，则节点A按照划分方式S划分会得到4x4的亮度块：
1)节点A包含M1个像素且节点A的划分方式为四叉树划分，例如M1为64；
2)节点A包含M2个像素且节点A的划分方式为三叉树划分，例如M2为64；
3)节点A包含M3个像素且节点A的划分方式为二叉树划分，例如M3为32；
4)节点A的宽等于第二阈值的4倍、高等于第二阈值且节点A的划分方式为竖直三叉树划分；
5)节点A的宽等于第二阈值、高等于第二阈值的4倍且节点A的划分方式为水平三叉树划分；
6)节点A的宽等于第二阈值的2倍、高等于第二阈值且当前节点的划分方式为竖直二分；
7)节点A的高等于第二阈值的2倍、宽等于第二阈值且当前节点的划分方式为水平二分；
8)节点A的宽或/和高为第二阈值的2倍且节点A的划分方式为四叉树划分。
所述尺寸可以是节点A对应图像区域的宽和高、或者节点A对应图像区域所包含的亮度像素个数、或者节点A对应图像区域的面积。
通常，当前节点的宽为当前节点对应亮度块的宽，当前节点的高为当前节点对应亮度块的高。在具体的实现方式中，例如第二阈值可以为4。
情况二：
1)如果节点A的至少一个子节点B的色度块为2x4、或4x2大小；
2)如果节点A的至少一个子节点B的色度块的宽或高为2；
3)如果节点A包含128个亮度像素且节点A使用三叉树划分，或者如果节点A包含64个亮度像素且节点A使用二叉树划分或者四叉树划分或者三叉树划分；
4)如果节点A包含256个亮度像素且节点使用三叉树划分或者四叉树划分，或者如果节点A包含128个亮度像素且节点使用二叉树划分；
5)如果节点A包含N1个亮度像素且节点A使用三叉树划分，N1为64、128或者256。
6)如果节点A包含N2个亮度像素且节点A使用四叉树划分，N2为64或者256。
7)如果节点A包含N3个亮度像素且节点A使用二叉树划分，N3为64、128或者256。
需要说明的是，节点A包含128个亮度像素点也可以描述为当前节点的面积为128，或者节点A的宽和高的乘积为128，在此不作赘述。
步骤3：与实施例四的步骤3相同。
步骤4：根据节点A覆盖区域的编码单元使用的预测模式，决定节点A的色度块和亮度块的划分方式。
如果节点A覆盖区域的编码单元均使用帧间预测模式，则节点A的亮度块和色度块按照所述划分方式S划分，得到节点A或/和节点A覆盖的区域内的子节点。其中，如果按照节点A或/和节点A覆盖的区域内的子节点的划分方式会产生4×4的亮度块，则该子节点的划分方式不被允许或者该子节点不能继续划分。例如，如果节点A的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，此时8x4(或4x8)的节点不能继续划分。
如果节点A覆盖区域的编码单元均使用帧内预测模式时，实施方法可以使用实施四、五、六中的方法，在此不做赘述。例如，节点A的亮度块划分，色度块不划分。
步骤5：解析节点A划分得到的CU的预测块和残差信息。
同实施例四的步骤5，在此不做赘述。
步骤6：解码各CU，得到节点A对应的图像块的重建信号
可以按照实施例四步骤6的方式实施，在此不再赘述。
实施例八
步骤1：与实施例四的步骤1相同
步骤2：判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的亮度块为4x4的亮度块(判断节点A的宽、高，和/或划分方式，和/或节点B的宽和高是否满足所述情况一中的条件中的至少一个)。如果节点A的尺寸(宽、高)，和/或划分方式S满足情况一中的至少一个条件，则限制节点A覆盖区域内所有的编码单元均使用帧内预测。
或者，判断节点A按照所述的划分方式S划分得到的子节点中是否存在至少一个子节点B的色度块为小块(判断节点A的尺寸，和/或划分方式S，和/或节点B的宽和高是否满足情况二中的至少一个条件，则执行步骤3至步骤6。
具体的，节点A的至少一个子节点B的色度块为小块的判断方法分为以下两种情况。
情况一：
满足以下预设条件一中的一个或者多个，则节点A按照划分方式S划分会得到4x4的亮度块：
1)节点A包含M1个像素且节点A的划分方式为四叉树划分，例如M1为64；
2)节点A包含M2个像素且节点A的划分方式为三叉树划分，例如M2为128；
3)节点A包含M3个像素且节点A的划分方式为二叉树划分，例如M3为32；
4)节点A的宽等于第二阈值的4倍、高等于第二阈值且节点A的划分方式为竖直三叉树划分；
5)节点A的宽等于第二阈值、高等于第二阈值的4倍且节点A的划分方式为水平三叉树划分；
6)节点A的宽等于第二阈值的2倍、高等于第二阈值且当前节点的划分方式为竖直二分；
7)节点A的高等于第二阈值的2倍、宽等于第二阈值且当前节点的划分方式为水平二分；
8)节点A的宽或/和高为第二阈值的2倍且节点A的划分方式为四叉树划分。
所述尺寸可以是节点A对应图像区域的宽和高、或者节点A对应图像区域所包含的亮度像素个数、或者节点A对应图像区域的面积。
通常，当前节点的宽为当前节点对应亮度块的宽，当前节点的高为当前节点对应亮度块的高。在具体的实现方式中，例如第二阈值可以为4。
情况二：
1)如果节点A的至少一个子节点B的色度块为2x4、或4x2大小；
2)如果节点A的至少一个子节点B的色度块的宽或高为2；
3)如果节点A包含128个亮度像素且节点A使用三叉树划分，或者如果节点A包含64个亮度像素且节点A使用二叉树划分或者四叉树划分或者三叉树划分；
4)如果节点A包含256个亮度像素且节点使用三叉树划分或者四叉树划分，或者如果节点A包含128个亮度像素且节点使用二叉树划分；
5)如果节点A包含N1个亮度像素且节点A使用三叉树划分，N1为64、128或者256。
6)如果节点A包含N2个亮度像素且节点A使用四叉树划分，N2为64或者256。
7)如果节点A包含N3个亮度像素且节点A使用二叉树划分，N3为64、128或者256。
需要说明的是，节点A包含128个亮度像素点也可以描述为当前节点的面积为128，或者节点A的宽和高的乘积为128，在此不作赘述。
步骤3：与实施例四的步骤3相同。
步骤4：根据节点A覆盖区域的编码单元使用的预测模式，决定节点A的色度块和亮度块的划分方式。
如果节点A覆盖区域的编码单元均使用帧间预测模式，则节点A的亮度块和色度块按照所述划分方式S划分，得到节点A或/和节点A覆盖的区域内的子节点。其中，如果按照节点A或/和节点A覆盖的区域内的子节点的划分方式会产生4×4的亮度块，则该子节点的划分方式不被允许或者该子节点不能继续划分。例如，如果节点A的尺寸为8x8且使用水平二叉树(或者竖直二叉树)划分产生两个8x4(或两个4x8)的节点，8x4(或4x8)的节点继续划分会产生4x4的块，因此，此时8x4(或4x8)的节点不能继续划分。
如果节点A覆盖区域的编码单元均使用帧内预测模式时，实施方法可以使用实施四、五、 六中的方法，在此不做赘述。例如，节点A的亮度块划分，色度块不划分。
步骤5：解析节点A划分得到的CU的预测块和残差信息。
同实施例四的步骤5，在此不做赘述。
步骤6：解码各CU，得到节点A对应的图像块的重建信号
可以按照实施例四步骤6的方式实施，在此不再赘述。
实施例九
如果当前区域被划分一次将产生4x4亮度块(例如64亮度像素使用QT划分，或128亮度像素使用TT划分)，则当前区域默认为限制只能使用Intra模式。
否则，传输一个flag指示当前区域只能使用inter模式或者只能使用intra模式；
如果当前区域限制只能使用inter模式，则亮度和色度一起划分，其中如果当前区域中的节点划分产生4x4的亮度块，则这种划分不被允许。例如当前节点为8x8且使用HBT(或VBT)划分，产生两个8x4的节点，则这些节点继续划分将产生4x4CU，所以这些8x4节点不能继续划分。
如果区域限制只能使用Intra模式，和原来的实施方式相同(亮度划分，色度不划分)。
本发明实施例提出了一种块划分方法，避免出现面积较小的色度块使用帧内预测模式，便于硬件的流水处理，及解码器的实现，同时在帧间预测中，可以跳过一些预测模式的语法元素的解析过程，从而减小编码复杂度。
解决了系数编码问题，减小编码复杂度。
该块划分方法可以如下：
解析节点A的划分方式
判断节点A按照所述的划分方式S划分后是否会得到至少一个子节点B的色度块为小块。(判断节点A的宽、高，和/或划分方式，和/或节点B的宽和高是否满足上述条件中的至少一个)
如果判断为真，则限制节点A覆盖区域内所有的编码单元同为帧内预测模式或帧间预测模式。
决定节点A的色度块和亮度块是否继续划分。
其中，如果节点A覆盖区域内所有编码单元均使用帧内预测，则节点A的亮度块按照划分方式S继续划分，节点A的色度块不再划分。如果节点A覆盖区域内所有编码单元均使用帧间预测，将节点A的亮度块和色度块按照划分方式S继续划分为N个包含亮度块和色度块的编码树节点。
其中，节点A的亮度块按照划分方式S继续划分，节点A的色度块不再划分。色度变换块和色度编码块相同大小。
当节点A覆盖区域内所有编码单元均使用帧内预测时，色度预测块和色度编码块相同大小；当节点A覆盖区域内所有编码单元均使用帧间预测时，色度预测块划分为子块(子块小于色度编码块)，每个子块的运动矢量为子块对应的亮度区域中的运动矢量。
其中，节点A的亮度块按照划分方式S继续划分；节点A的色度块不再划分。色度编码块对应的色度变换块和色度编码块相同大小，色度预测块和色度编码块相同大小，色度CB的运动信息为色度CB对应的亮度区域中某个预设位置的运动信息。
应理解，结合所描述方法的揭示内容可以同样适用于用于执行所述方法的对应设备或系统，且反之亦然。例如，如果描述一个或多个具体方法步骤，则对应的设备可以包含如功能单元等一个或多个单元，来执行所描述的一个或多个方法步骤(例如，一个单元执行一个或多个步骤，或多个单元，其中每个都执行多个步骤中的一个或多个)，即使附图中未明确描述或说明这种一个或多个单元。另一方面，例如，如果基于如功能单元等一个或多个单元描述具体装置，则对应的方法可以包含一个步骤来执行一个或多个单元的功能性(例如，一个步骤执行一个或多个单元的功能性，或多个步骤，其中每个执行多个单元中一个或多个单元的功能性)，即使附图中未明确描述或说明这种一个或多个步骤。进一步，应理解的是，除非另外明确提出，本文中所描述的各示例性实施例和/或方面的特征可以相互组合。
在一个或一个以上实例中，所描述功能可以硬件、软件、固件或其任何组合来实施。如果在软件中实施，那么所述功能可作为一或多个指令或代码在计算机可读介质上存储或传输，并且由基于硬件的处理单元执行。计算机可读介质可以包含计算机可读存储介质，其对应于例如数据存储介质或通信介质的有形介质，通信介质例如根据通信协议包含有助于将计算机程序从一处传送到另一处的任何介质。以此方式，计算机可读介质通常可对应于(1)非暂时性的有形计算机可读存储介质，或(2)通信介质，例如，信号或载波。数据存储介质可以是可由一或多个计算机或一或多个处理器存取以检索用于实施本发明中描述的技术的指令、代码和/或数据结构的任何可用介质。计算机程序产品可包含计算机可读介质。
借助于实例而非限制，此类计算机可读存储介质可包括RAM、ROM、EEPROM、CD-ROM或其它光盘存储器、磁盘存储器或其它磁性存储设备、闪存，或可用以存储呈指令或数据结构形式的所需程序代码且可由计算机存取的任何其它介质。并且，任何连接可适当地称为计算机可读介质。举例来说，如果使用同轴电缆、光纤缆线、双绞线、数字订户线(digital subscriber line，DSL)或例如红外线、无线电及微波等无线技术从网站、服务器或其它远程源传输指令，则同轴电缆、光纤缆线、双绞线、DSL或例如红外线、无线电及微波等无线技术包含在介质的定义中。但是，应理解，所述计算机可读存储介质及数据存储介质并不包括连接、载波、信号或其它暂时性介质，而是实际上针对于非暂时性有形存储介质。如本文中所使用，磁盘和光盘包含压缩光盘(compact disc，CD)、激光光盘、光学光盘、数字多功能光盘(digital versatile disc，DVD)、软性磁盘及蓝光光盘，其中磁盘通常以磁性方式再现数据，而光盘用激光以光学方式再现数据。以上各项的组合也应包含于计算机可读介质的范围内。
指令可以由一或多个处理器执行，所述一或多个处理器例如是一或多个数字信号处理器(digital signal processor，DSP)、通用微处理器、专用集成电路(application specific integrated circuit，ASIC)、现场可编程逻辑阵列(field programmable logic arrays，FPGA)或其它等效的集成或离散逻辑电路。因此，如本文中所使用的术语“处理器”可指代上述结构或适用于实施本文中所描述的技术的任何其它结构中的任一者。另外，在一些方面中，本文中所描述的功能性可在用于编码和解码的专用硬件和/或软件模块内提供，或并入在合成编解码器中。并且，所述技术可完全实施于一或多个电路或逻辑元件中。
本公开的技术可以在包含无线手持机、集成电路(integrated circuit，IC)或IC集合(例如，芯片组)的多种设备或装置中实施。本公开描述各种组件、模块或单元是为了强调用于执行所揭示的技术的设备的功能方面，但未必需要通过不同硬件单元实现。确切地，如上文所描述，各种单元可结合合适的软件和/或固件组合在编解码器硬件单元中，或由互操作硬件单元的集合来提供，所述硬件单元包含如上文所描述的一或多个处理器。

Claims (42)

  1. 一种图像划分方法，包括：
    确定当前节点的划分方式，所述当前节点包含亮度块和色度块；
    根据所述当前节点的划分方式和所述当前节点的尺寸，确定所述当前节点的色度块不再划分；和
    当所述当前节点的色度块不再划分时，按照所述当前节点的划分方式对所述当前节点的亮度块进行划分。
  2. 如权利要求1所述的方法，其特征在于，所述确定所述当前节点的色度块不再划分具体包括：
    根据所述当前节点的划分方式和所述当前节点的尺寸，确定划分所述当前节点产生的子节点包含边长小于阈值的色度块，则确定所述当前节点的色度块不再划分。
  3. 如权利要求1所述的方法，其特征在于，
    当所述当前节点的宽等于阈值的2倍且所述当前节点的划分方式为竖直二分；或
    当所述当前节点的高等于阈值的2倍且所述当前节点的划分方式为水平二分；或
    当所述当前节点的宽等于阈值的4倍且所述当前节点的划分方式为竖直三分；或
    当所述当前节点的高等于阈值的4倍且所述当前节点的划分方式为水平三分；或
    当所述当前节点的宽等于阈值的2倍且所述当前节点的划分方式为四分时，
    则确定所述当前节点的色度块不再划分。
  4. 如权利要求1至3任一所述的方法，其特征在于，按照所述当前节点的划分方式对所述当前节点的亮度块进行划分，从而得到所述当前节点的子节点，每个子节点只包含亮度块。
  5. 如权利要求4所述的方法，其特征在于，所述方法还包括：
    解析所述当前节点的亮度块，获取所述亮度块中各子区域的预测信息和残差信息，其中所述子区域与所述子节点一一对应。
  6. 如权利要求4或5所述的方法，其特征在于，所述子节点默认不再划分，每个子节点对应一个只包含亮度块的编码单元。
  7. 如权利要求1-6任一所述的方法，其特征在于，所述方法还包括：
    当所述当前节点的色度块不再划分时，获取所述色度块的预测模式。
  8. 如权利要求7所述的方法，其特征在于，根据所述当前节点的预设位置中亮度块的预测模式，确定所述当前节点的色度块的预测模式。
  9. 如权利要求8所述的方法，其特征在于，当所述预设位置中亮度块使用的预测模式为帧间预测模式时，则：
    所述当前节点的色度块使用帧间预测模式；或者
    解析第一标志位,根据所述第一标志位确定所述色度块的预测模式。
  10. 如权利要求9所述的方法，其特征在于，当所述当前节点的色度块使用帧间预测模式时，则：
    获取预设位置的亮度块的运动信息作为所述色度块的运动信息；或者
    将所述色度块划分为色度预测子块，获取所述色度预测子块的运动信息。
  11. 如权利要求9所述的方法，其特征在于，当根据所述第一标志位，确定所述色度块使用帧内预测模式时，从所述码流中解析一个帧内预测模式，作为所述色度块的帧内预测模式；或者
    当根据所述第一标志位，确定所述色度块使用帧间预测模式时，则获取所述预设位置的亮度块的运动信息作为所述色度块的运动信息；或者
    当根据所述第一标志位，确定所述色度块使用帧间预测模式时，则将所述色度块划分为色度预测子块，获取所述色度预测子块的运动信息。
  12. 如利要求10或11所述的方法，其特征在于，所述获取所述色度预测子块的运动信息包括：
    如果所述色度预测子块对应的亮度图像位置的亮度块采用帧间预测，则将所述色度预测子块对应的亮度图像位置的运动信息作为所述色度预测子块的运动信息；
    否则，获取预设位置的运动信息作为所述色度预测子块的运动信息。
  13. 如权利要求8所述的方法，其特征在于，当所述预设位置中亮度块使用的预测模式为帧内预测模式时，则所述当前节点的色度块使用帧内预测模式。
  14. 如权利要求13所述的方法，其特征在于，从所述码流中解析一个帧内预测模式，作为所述当前节点的色度块的帧内预测模式；或者
    所述当前节点的色度块的帧内预测模式为直流模式、平面模式、角度模式、线性模型模式或者色度导出DM模式中的一种。
  15. 如权利要求8所述的方法，其特征在于，当所述预设位置中亮度块使用的预测模式为帧内块复制IBC模式时，则：
    所述当前节点的色度块使用IBC预测模式；或者，
    解析第二标志位,根据所述第二标志位确定所述色度块的预测模式。
  16. 如权利要求15所述的方法，其特征在于，当所述当前节点的色度块使用IBC预测模式 时，所述方法还包括：获取所述预设位置的亮度块的位移矢量(displacement vector)信息作为所述当前节点的色度块的位移矢量信息。
  17. 如权利要求15所述的方法，其特征在于，如果所述第二标志位的取值为第一值，则所述色度块使用IBC模式；或者
    如果所述第二标志位的取值为第一值，则所述色度块使用帧内预测模式；或者
    如果所述第二标志位的取值为第二值，则所述色度块使用帧间预测模式。
  18. 如权利要求7所述的方法，其特征在于，所述方法包括：
    获取划分后的多个亮度块的预测模式；
    根据所述划分后的多个亮度块的预测模式，确定所述当前节点的色度块的预测模式。
  19. 如权利要求18所述的方法，其特征在于，当所述多个亮度块使用的预测模式为帧内预测模式时，则所述当前节点的色度块使用帧内预测模式。
  20. 如权利要求18所述的方法，其特征在于，当所述多个亮度块使用的预测模式为帧间预测模式时，则所述当前节点的色度块使用帧间预测模式时，使用预设位置的亮度块的运动信息，作为所述当前节点的色度块的运动信息；或者
    当所述多个亮度块使用的预测模式为帧间预测模式时，解析第一标志位,根据所述第一标志位确定所述色度块的预测模式。
  21. 如权利要求20所述的方法，其特征在于，当根据所述第一标志位，确定所述色度块使用帧内预测模式时，从所述码流中解析一个帧内预测模式，作为所述色度块的帧内预测模式；或者
    当根据所述第一标志位，确定所述色度块使用帧间预测模式时，则获取预设位置的亮度块的运动信息作为所述色度块的运动信息。
  22. 如权利要求18所述的方法，其特征在于，当所述多个亮度块使用的预测模式包括帧间预测模式和帧内预测模式时，则获取所述当前节点的预设位置中亮度块的预测模式，作为所述当前节点的色度块的预测模式。
  23. 如权利要求1-22任一所述的方法，其特征在于，如果所述当前节点为I帧，则所述当前节点的各子节点使用帧内预测模式；或者如果所述当前节点为P帧或B帧，对第一个子节点进行解析获得所述第一个子节点的预测模式，其余各子节点的预测模式与所述第一个子节点的预测模式相同，其中所述第一个子节点为第一个进行解析的节点。
  24. 如权利要求1-22任一所述的方法，其特征在于，如果所述当前节点为I帧，则所述当前节点的各子节点使用帧内预测模式；或者如果所述当前节点为P帧或B帧，则所述当前节点的各子节点使用帧间预测模式。
  25. 如权利要求1-24任一所述的方法，其特征在于，
    根据所述当前节点的划分方式，所述当前节点的尺寸以及所述当前节点的第一个子节点的预测模式，确定所述当前节点的色度块不再划分，所述第一个子节点只包含亮度块，其中所述第一个子节点为第一个进行解析的节点。
  26. 如权利要求25所述的方法，其特征在于，根据所述当前节点的划分方式和所述当前节点的尺寸，确定划分所述当前节点产生的子节点包含边长小于阈值的色度块，且所述第一个子节点的预测模式为帧内预测模式，则所述当前节点的色度块不再进行划分。
  27. 如权利要求26所述的方法，其特征在于，当所述第一个子节点的预测模式为帧内预测，并且如下条件任一成立时：
    当所述当前节点的宽等于阈值的2倍且所述当前节点的划分方式为竖直二分；或
    当所述当前节点的高等于阈值的2倍且所述当前节点的划分方式为水平二分；或
    当所述当前节点的宽等于阈值的4倍且所述当前节点的划分方式为竖直三分；或
    当所述当前节点的高等于阈值的4倍且所述当前节点的划分方式为水平三分；或
    当所述当前节点的宽等于阈值的2倍且所述当前节点的划分方式为四分时，
    所述当前节点的色度块不再进行划分。
  28. 如权利要求1-24任一所述的方法，其特征在于，根据所述当前节点的划分方式和所述当前节点的尺寸，确定划分所述当前节点产生的子节点包含边长小于阈值的色度块，如果第一个子节点的预测模式为帧间预测，则所述当前节点的色度块按照所述当前节点的划分方式划分，其中所述第一个子节点为第一个进行解析的节点。
  29. 如权利要求28所述的方法，其特征在于，所述方法还包括：
    根据所述当前节点的子节点的运动信息，确定色度块的对应子节点的运动信息。
  30. 如权利要求1-24任一所述的方法，其特征在于，根据所述当前节点的划分方式和所述当前节点的尺寸，确定划分所述当前节点产生的子节点包含宽小于阈值的色度块，则确定所述当前节点的色度块不再划分。
  31. 如权利要求1-24任一所述的方法，其特征在于，根据所述当前节点的划分方式和所述当前节点的尺寸，确定划分所述当前节点产生的子节点包含色度像素数目少于16的色度块，则确定所述当前节点的色度块不再划分。
  32. 如权利要求31所述的方法，其特征在于，
    当所述当前节点的宽和高的乘积小于128且所述当前节点的划分方式为竖直二分或水平二分；或
    当所述当前节点的宽和高的乘积小于256且所述当前节点的划分方式为竖直三分或水平三分 或四分时；或
    当所述当前节点的宽和高的乘积等于64且所述当前节点的划分方式为竖直二分或水平二分或四分或水平三分或竖直三分时；或
    当所述当前节点的宽和高的乘积等于128且所述当前节点的划分方式为竖直三分或水平三分时，
    则确定所述当前节点的色度块不再划分。
  33. 如权利要求2，3，26，27，28或30所述的方法，其特征在于，所述阈值为4。
  34. 如权利要求1-33任一所述的方法，其特征在于，所述当前节点的划分方式包括四分(QT)、水平二分(horizontal BT)、水平三分(horizontal TT)、竖直二分(Vertical BT)、竖直三分(Vertical TT)中的至少一种。
  35. 如权利要求1所述的方法，其特征在于，当所述当前节点的宽和高的乘积等于64且所述当前节点的划分方式为四叉树划分或三叉树划分时；或
    当所述当前节点的宽和高的乘积等于32且所述当前节点的划分方式为二叉树划分时，
    则确定所述当前节点的色度块不再划分。
  36. 如权利要求1所述的方法，其特征在于，所述当前节点属于I条带，当所述当前节点的宽和高的乘积等于64且所述当前节点的划分方式为二叉树划分时；或
    当所述当前节点的宽和高的乘积等于128且所述当前节点的划分方式为三叉树划分时，
    则确定所述当前节点的色度块不再划分。
  37. 如权利要求1-36任一所述的方法，其特征在于，根据所述当前节点的划分方式，所述当前节点的尺寸，以及节点预测模式标识(cons_pred_mode_flag)，确定所述当前节点的色度块是否需要划分。
  38. 如权利要求37所述的方法，其特征在于，所述当前节点属于P或B条带，当所述当前节点的宽和高的乘积等于64且所述当前节点的划分方式为二叉树划分时，或当所述当前节点的宽和高的乘积等于128且所述当前节点的划分方式为三叉树划分时，
    且所述节点预测模式标识指示对所述当前节点进行划分得到的编码块(coding block)不执行帧间预测时，
    则确定所述当前节点的色度块不再划分。
  39. 一种解码视频流的装置，包含处理器和存储器，所述存储器存储指令，所述指令使得所述处理器执行所述1-38任一所述的方法。
  40. 一种编码视频流的装置，包含处理器和存储器，所述存储器存储指令，所述指令使得所述处理器执行所述1-38任一所述的方法。
  41. 一种解码设备，包括：相互耦合的非易失性存储器和处理器，所述存储器用于存储程序指令，所述程序指令使得所述处理器执行权利要求1-38任一项所述的方法。
  42. 一种编码设备，包括：相互耦合的非易失性存储器和处理器，所述存储器用于存储程序指令，所述程序指令使得所述处理器执行权利要求1-38任一项所述的方法。
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