RU2785106C2 - Method and device for internal prediction - Google Patents

Abstract

FIELD: encoding/decoding.

SUBSTANCE: invention relates to the field of encoding and decoding of images and/or video. Values of a flag of the most probable modes (hereinafter – MPM) are obtained for the current block from a bit stream; index MPM are obtained for the current block from the bit stream, when the value of flag MPM indicates that an internal prediction mode for the current block is an internal prediction mode contained in MPM set of internal prediction modes; values of the internal prediction mode are obtained for the current block based on index MPM and MPM set for the current block. When the internal prediction mode of the left neighboring block of the current block is a planar mode, and the internal prediction mode of the upper neighboring block of the current block is a planar mode, MPM set of prediction modes contains: a planar mode, DC mode, a vertical mode, a horizontal mode, an internal prediction mode corresponding to the vertical mode with the first offset, and an internal prediction mode corresponding to the vertical mode with the second offset.

EFFECT: provision of an effective encoding scheme with an internal prediction.

17 cl, 10 dwg, 1 tbl

Description

The field of technology to which the invention belongs

The present invention relates to the technical field of image and/or video coding and decoding, and in particular to a method and apparatus for intra prediction.

State of the art

Since the advent of DVDs, digital video has become widespread. Before transmission, the video is encoded and transmitted using a transmission medium. The viewer receives the video and uses the viewer to decode and display the video. Video quality has improved over the years, for example through higher resolutions, color depths and frame rates. This has led to an increase in data flows, which are now usually transmitted over the Internet and mobile networks.

Due to the fact that higher resolution video contains more information, however, it is usually necessary to provide more bandwidth. To reduce bandwidth requirements, video coding standards have been introduced that include video compression. When video is encoded, the bandwidth requirements (or corresponding memory requirements in the case of storage) are reduced. Often this decline comes at the expense of quality degradation. Thus, video coding standards strike a balance between bandwidth requirements and quality.

High Efficiency Video Coding (HEVC) is an example of a video coding standard that is widely known to those skilled in the art. In HEVC, to divide a coding unit (CU) into prediction units (PUs) or transform units (TUs). The next generation Universal Video Coding (VVC) standard is the most recent joint video project of the ITU-T Video Coding Expert Group (VCEG) and the ISO/IEC Motion Picture Experts Group (MPEG) standardization organizations working together in a well-known partnership as the Joint Group video research (JVET). VVC is also referred to as the ITU-T H.266/Next Generation Video Coding (NGVC) standard. VVC should remove the concept of multiple partition types, i.e., the separation of CU, PU, and TU concepts, except when necessary for CUs that are too large for the maximum transformation length and allow more flexibility for CU partition shapes.

The processing of these coding units (CUs) (also referred to as blocks) depends on their size, spatial position, and the coding mode specified by the encoder. The coding modes can be divided into two groups according to the type of prediction: intra prediction and inter prediction modes. The intra prediction modes use samples of the same picture (also referred to as a frame or picture) to generate reference samples to calculate prediction values for the samples of the reconstructed block. Intra prediction is also called spatial prediction. The inter prediction modes are for temporal prediction and use previous or next picture reference samples to predict current picture block samples.

ITU-T VCEG (Q6/16) and ISO/IEC MPEG (JTC 1/SC 29/WG 11) are being studied for the potential need to standardize a future compressible video coding technology that far exceeds the current HEVC standard (which includes its current extensions and short-term extensions for screen content encoding and high dynamic range encoding). The groups work together on this research activity in a collaborative project known as the Joint Video Research Team (JVET) to evaluate compression technology projects proposed by experts in the field.

The VTM (Universal Test Model) standard uses 35 internal modes, while the BMS (Benchmark Set) uses 67 internal modes.

The intra coding mode scheme currently described in the BMS is considered complex, and the disadvantage of the unselected mode set is the index list persistence.

Disclosure of the essence of the invention

Embodiments of the present invention provide devices and methods for decoding according to the independent claims.

Embodiments of the present invention provide, for example, an efficient most likely modes (MPM) scheme for intra prediction.

The subject matter of the independent claims represents solutions to the above and other problems. Additional forms of implementation are apparent from the dependent claims, descriptions and drawings.

Specific embodiments are set forth in the appended independent claims and dependent claims present other embodiments.

The first aspect of the invention relates to a method for decoding a current video block, wherein the decoding method comprises: obtaining a Most Probable Modes (MPM) flag value for the current block from a bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and the MPM set for the current block; wherein, when the intra prediction mode of the left neighbor block of the current block is planar mode and the intra prediction mode of the aforementioned neighbor block of the current block is planar mode, the MPM prediction mode set comprises: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode, corresponding to the vertical mode with the first offset, and an intra prediction mode corresponding to the vertical mode with the second offset. The method may, for example, be performed by a video decoding device.

In a possible implementation form of the method according to the first aspect, wherein when the MPM value of the flag for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode.

In an exemplary implementation of the method according to any prior implementation of the first aspect or first aspect, the first offset is -4.

In an exemplary implementation of the method according to any prior implementation of the first aspect or first aspect, the second offset is +4.

A second aspect of the invention relates to a method for decoding a current video block, wherein the decoding method comprises: obtaining a most likely modes flag, MPM, value for the current block from a bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and the MPM set for the current block; wherein, when the intra prediction mode of the left neighbor block of the current block is planar mode and the intra prediction mode of the above neighbor block of the current block is DC mode, the MPM prediction mode set comprises: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode, corresponding to the vertical mode with the first offset, and an intra prediction mode corresponding to the vertical mode with the second offset. The method may, for example, be performed by a video decoding device.

In an exemplary embodiment of the method according to the second aspect, wherein when the MPM value of the flag for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode.

In an exemplary embodiment of the method according to any prior implementation of the second aspect or the second aspect, the first offset is -4.

In an exemplary embodiment of the method according to any prior implementation of the second aspect or second aspect, the second offset is +4.

A third aspect of the invention relates to a method for decoding a current video block, wherein the decoding method comprises: obtaining a most likely modes flag, MPM, value for the current block from a bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and the MPM set for the current block; in which, when the left neighbor block of the current block is unavailable, and the intra prediction mode of the above neighbor block of the current block is planar mode, the MPM prediction mode set contains: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode corresponding to the vertical mode with the first offset, and an intra prediction mode corresponding to the vertical mode with the second offset. The method may, for example, be performed by a video decoding device.

In a possible implementation form of the method according to the third aspect, wherein when the MPM value of the flag for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode.

In an exemplary embodiment of the method according to any prior implementation of the third aspect or third aspect, the first offset is -4.

In an exemplary embodiment of the method according to any prior implementation of the third aspect or third aspect, the second offset is +4.

A fourth aspect of the invention relates to a method for decoding a current video block, wherein the decoding method comprises: obtaining a most likely modes flag, MPM, value for the current block from a bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and the MPM set for the current block; wherein, when the left adjacent block of the current block is unavailable and the above adjacent block of the current block is unavailable, the MPM prediction mode set comprises: planar mode, DC mode, vertical mode, horizontal mode, an intra prediction mode corresponding to the first offset vertical mode, and an intra prediction mode. prediction corresponding to the vertical mode with the second offset. The method may, for example, be performed by a video decoding device.

In a possible implementation form of the method according to the fourth aspect, wherein when the MPM value of the flag for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode.

In an exemplary embodiment of the method according to any prior implementation of the fourth aspect or fourth aspect, the first offset is -4.

In an exemplary embodiment of the method according to any prior implementation of the fourth aspect or fourth aspect, the second offset is +4.

A fifth aspect of the invention relates to a method for decoding a current video block, wherein the decoding method comprises: obtaining a most likely modes flag, MPM, value for the current block from a bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and the MPM set for the current block; in which, when the intra prediction mode of the left neighboring block of the current block is planar mode, and the aforementioned neighboring block of the current block is unavailable, the MPM prediction mode set comprises: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode corresponding to the vertical mode with the first offset, and an intra prediction mode corresponding to the vertical mode with the second offset. The method may, for example, be performed by a video decoding device.

In a possible implementation form of the method according to the fifth aspect, wherein when the MPM value of the flag for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode.

In an exemplary embodiment of the method according to any prior implementation of the fifth aspect or fifth aspect, the first offset is -4.

In an exemplary embodiment of the method according to any prior implementation of the fifth aspect or fifth aspect, the second offset is +4.

The fifth aspect of the invention relates to a device for decoding a video stream, which includes a processor and a memory. The memory stores instructions that cause execution, by the processor, of the method according to the method of the first to fourth aspects, or of any possible implementation or embodiment of the first to fourth aspects.

A sixth aspect of the invention relates to a computer-readable storage medium that stores instructions that cause, when executed by one or more processors, to encode video data. The instructions cause the one or more processors to execute the method according to the first to fourth aspects, or any possible implementation or embodiment of the first to fourth aspects.

According to a seventh aspect, the invention relates to a computer program containing program code for executing the method according to the first to fourth aspects, or when any possible implementation or embodiment of the first to fourth aspects is executed on a computer.

In addition, embodiments of the present invention provide, for example, an intra mode coding scheme where the unselected mode set is adaptive based on the properties of the current block, eg, adaptive based on the INTRA modes of adjacent blocks.

The accompanying drawings and description set forth the details of one or more embodiments. Other features, objects and advantages will be apparent from the description, drawings and claims.

Brief description of the drawings

With reference to the accompanying drawings, a detailed description is given of the following embodiments, in which:

1 is a block diagram showing an example of a video coding system capable of implementing embodiments of the invention.

2 is a block diagram showing an example of a video encoder capable of implementing embodiments of the invention.

3 is a block diagram showing an exemplary structure of a video decoder capable of implementing embodiments of the invention.

4 shows a diagram illustrating 67 intra prediction modes.

5 shows a diagram illustrating neighboring blocks for obtaining MPM.

Fig. 6 is a diagram illustrating the internal modes of adjacent second-level blocks used to obtain the first three modes in the list of remaining modes.

7 shows a diagram illustrating an example of the first three modes in the process of generating a list of the remaining modes.

8 shows a diagram illustrating an example of a video decoding method.

9 shows another diagram illustrating an example of a video decoding method.

10 shows a block diagram of the device.

Implementation of the invention

The device and method of intra prediction are disclosed. In order to simplify the calculation procedure for intra prediction to improve coding efficiency, the apparatus and method use a mapping process. The scope of protection of the present invention is determined by the claims.

Abbreviations definitions and glossary

CTU/CTB - coding tree block/ coding tree block

CU/CB - coding block/coding block

PU/PB - prediction block/prediction block

TU/TB - conversion unit/transformation unit

HEVC High Efficiency Video Coding

Video coding schemes such as H.264/AVC and HEVC have been developed in accordance with the successful block-based hybrid video coding principle. Using this principle, the image is first divided into blocks and then each block is predicted using intra or inter prediction.

Several video coding standards, starting with H.261, belong to the group of "hybrid lossy video codecs" (ie, combine spatial and temporal sample-domain prediction and 2D transform coding to apply transform-domain quantization). Each picture of a video sequence is usually divided into a set of non-overlapping blocks, and encoding is usually done at the block level. In other words, to generate a prediction block in the encoder, video is usually processed, that is, encoded, at the block (image block) level, for example, using spatial (internal image) prediction and temporal (external image) prediction, block subtraction is performed to obtain a residual block prediction from the current block (the block currently being processed/to be processed), to reduce the amount of data to be transmitted (compressed), the residual block is transformed and the residual block is quantized in the transform region, while in the decoder to restore the current block to represent, the encoded or compressed block is partially back-processed compared to the encoder. In addition, the encoder duplicates the processing cycle of the decoder, so that both will generate identical predictions (eg, intra and inter prediction) and/or reconstruction for processing, i.e., encoding subsequent blocks.

The present disclosure uses the term "block", which may be part of an image or frame. For convenience of description, embodiments of the invention are described with reference to High Efficiency Video Coding (HEVC) or Universal Video Coding (VVC) reference software developed by the Joint Collaborative Group on Video Coding (JCT-VC) of the ITU-T Video Coding Expert Group (VCEG) and the ISO/IEC Moving Picture Expert Group (MPEG). For a person skilled in the art it is obvious that the embodiments of the invention are not limited to HEVC or VVC. The standard may refer to CU, PU and TU. In HEVC, the CTU is divided into CUs using a quadtree structure referred to as a coding tree. The decision as to whether to encode an image region using extrinsic (temporal) or intrinsic (spatial) prediction is made at the CU layer. Each CU may be further partitioned into one, two or four PUs according to the partition type of the PU. Within one PU, the same prediction process is applied, and corresponding information based on the PU is transmitted to the decoder. After obtaining the residual block by applying a prediction process based on the partition type of the PU, the CU may be divided into transform units (TUs) according to a different quadtree structure similar to the coding tree for the CU. The latest developments in video compression technology use quadtree-binary-tree (QTBT) partitioning to split the coding block. In the QTBT block structure, the CU can be either square or rectangular. For example, a coding tree unit (CTU) is first divided by a quadtree structure. The leaf nodes of the quadtree are further separated by a binary tree structure. The leaf nodes of the binary tree are called coding units (CUs) and this segmentation is used to predict and process the transform without any additional partitioning. This means that CU, PU and TU have the same block size in the QTBT coding block structure. In parallel with the QTBT box structure, it has also been proposed to use multiple partitioning, such as ternary tree partitioning.

ITU-T VCEG (Q6/16) and ISO/IEC MPEG (JTC 1/SC 29/WG 11) are being studied for the potential need to standardize a future compressible video coding technology that far exceeds the current HEVC standard (which includes its current extensions and short-term extensions for screen content encoding and high dynamic range encoding). The groups work together on this research activity in a collaborative project known as the Joint Video Research Team (JVET) to evaluate compression technology projects proposed by experts in the field.

In the following description, reference is made to the accompanying drawings, which form part of the present invention and which show, by way of illustration, specific aspects of the implementation of the present invention.

For example, it is understood that in the present disclosure, the described method may also be applicable to the corresponding device or system fired with the ability to perform the method, and vice versa. For example, if a specific method step is described, the corresponding apparatus may include a unit for performing the described method step even if such unit is not explicitly described or illustrated in the drawings. In addition, it is understood that the features of the various illustrative aspects described herein may be combined with each other unless specifically noted otherwise.

Video coding generally refers to the processing of a sequence of images that form a video or video sequence. The term "image" or "frame" may be used/may be used interchangeably in the field of video coding as well as in this disclosure. Each image is usually divided into a set of non-overlapping blocks. Image encoding/decoding is usually performed at the block level, where, for example, inter prediction or intra prediction is used to generate a prediction block, a prediction block is subtracted from the current block (a block that is currently being processed/to be processed) to obtain a residual block, which is further converted and quantized to reduce the amount of data to be transmitted (compressed), while on the decoder side, the encoded/compressed block is de-processed to recover the block for presentation.

1 is a conceptual or schematic block diagram illustrating an example of an encoding system 10, such as a video encoding system 10, that may use the methods of the present invention (present disclosure). Encoder 20 (eg, video encoder 20) and decoder 30 (eg, video decoder 30) of video coding system 10 represent examples of devices that may be configured to perform methods in accordance with the various examples described in this disclosure. As shown in FIG. 1, the encoding system 10 includes a source device 12 configured to provide encoded data 13, such as an encoded image 13, for example, to a destination device 14 to decode the encoded data 13. The source device 12 includes an encoder 20 and may further , i.e. optionally comprise an image source 16, a pre-processing unit 18, for example an image pre-processing unit 18, and a communication interface or communication unit 22.

The image source 16 may comprise or be any type of image capture device, for example, to capture a real image and/or any kind of image or commentary (to encode screen content, some texts on the screen are also part of the image or frame to be encoded) of the device for generating, for example, a computer graphics processor for generating a computer animated image, or any device for receiving and/or providing a real image, a computer animated image (for example, screen content, a virtual reality (VR) image), and/or any combination of them (for example , augmented reality (AR) image).

A (digital) image is, or can be viewed as, a two-dimensional array or matrix of samples with intensity values. A sample in an array can also be called a pixel (short for picture element) or a pixel. The number of samples in the horizontal and vertical direction (or axis) of the array or image determines the size and/or resolution of the image. Three color components are typically used to represent a color, that is, an image can be represented by or include three arrays of samples. In RBG format or color space, an image contains a corresponding array of red, green, and blue color samples. However, in video encoding, each pixel is typically represented in a luma/chrominance format or color space, such as YCbCr, which contains a luminance component labeled Y (sometimes L is also used instead) and two chrominance components labeled Cb and Cr. The Y component of luminance (or luminance for short) represents the brightness or intensity of the gray level (eg, as in a grayscale image), while the two chrominance (or chroma for short) components Cb and Cr represent components of chrominance or color information. Accordingly, an image in YCbCr format contains an array of luma samples of luminance sample values (Y) and two chrominance sample arrays of chrominance values (Cb and Cr). RGB images can be converted to YCbCr format and vice versa, this process is also known as color conversion. If the image is monochrome, it can only contain an array of brightness samples.

Image source 16 (e.g., video source 16) may be, for example, a camera for capturing an image, a memory, such as an image memory containing or storing a previously captured or generated image, and/or any type of interface (internal or external) for receiving or receiving an image. The camera may be, for example, a local or integrated camera integrated into the source device, the memory may be local or integrated memory, for example, integrated into the source device. The interface may be, for example, an external interface for receiving an image from an external video source, such as an external image capture device such as a camera, external memory, or an external imaging device, such as an external computer GPU, computer, or server. The interface may be any, such as a wired or wireless interface, an optical interface in accordance with any proprietary or standardized interface protocol. The interface for obtaining image data 17 may be the same interface as the communication interface 22 or be part of it.

Unlike the pre-processing unit 18 and the processing performed by the pre-processing unit 18, the image or image data 17 (eg, video data 16) may also be referred to as raw image or raw image data 17.

The pre-processing unit 18 is configured to receive (raw) image data 17 and perform pre-processing of the image data 17 to obtain a pre-processed image 19 or pre-processed image data 19. The pre-processing performed by the pre-processor 18 may, for example, include cropping, color format conversion (eg from RGB to YCbCr), color correction or denoising. It can be understood that the preprocessing unit 18 may be a possible component.

The encoder 20 (eg, video encoder 20) is configured to receive pre-processed image data 19 and provide encoded image data 21 (more details will be described below, for example, with reference to FIG. 2).

The communication interface 22 of the source device 12 may be configured to receive the encoded image data 21 and transmit it to another device, such as the destination device 14 or any other device for storage or direct retrieval or for processing the encoded image data 21, respectively, before storing the encoded data 13 and/or transmitting the encoded data 13 to another device, such as a destination device 14 or any other device for decoding or storage.

Destination device 14 includes a decoder 30 (eg, video decoder 30) and may additionally, that is, possibly, comprise a communication interface or communication unit 28, a post-processing unit 32, and a display device 34.

The communication interface 28 of destination device 14 is configured to receive encoded image data 21 or encoded data 13, for example, directly from destination device 12 or from any other source, such as a storage device, such as a device for storing encoded image data.

Communication interface 22 and communication interface 28 may be configured to transmit or receive encoded image data 21 or encoded data 13 via a direct link between source device 12 and destination device 14, such as a direct wired or wireless connection, or over any network, such as wired or wireless network, or any combination thereof, or any private or public network, or any combination thereof.

The communication interface 22 may, for example, be configured to package the encoded image data 21 into an appropriate format, such as packets, for transmission over a communication channel or network.

The communication interface 28, analogous to the communication interface 22, may, for example, be configured to decompress the encoded data 13 to obtain encoded image data 21.

Both the communication interface 22 and the communication interface 28 can be configured as unidirectional communication interfaces as shown by the arrow for the encoded image data 13 in FIG. 1 pointing from source device 12 to destination device 14, or bidirectional communication interfaces, and can be performed with the ability, for example, to send and receive messages, for example, to establish a connection, acknowledge and exchange any other information related to the communication channel and/or data transmission, for example, the transmission of encoded image data.

The decoder 30 is configured to receive encoded image data 21 and provide decoded image data 31 or decoded image 31 (more details will be described below, for example, with reference to FIG. 3).

The post-processing unit 32 of the destination device 14 is configured to post-process the decoded image data 31 (also referred to as reconstructed image data), such as the decoded image 31, to obtain post-processed image data 33, such as the post-processed image 33. 32 post-processing may include, for example, color format conversion (for example, from YCbCr to RGB), color correction, cropping or resampling, or any other processing, for example, to prepare the decoded image data 31 for display, for example, by a device 34 displays.

The display device 34 of the destination device 14 is configured to receive post-processed image data 33 for displaying the image to, for example, a user or viewer. The display device 34 may be or comprise any kind of display for presenting the reconstructed image, such as a built-in or external display or monitor. The displays may, for example, consist of liquid crystal displays (LCD), organic light emitting diode (OLED) displays, plasma displays, projectors, micro LED displays, liquid crystals on silicon (LCoS), digital light processor (DLP) or any other display.

Although FIG. 1 depicts source device 12 and destination device 14 as separate devices, device embodiments may also comprise both or both source device 12 functionality or corresponding destination device 14 functionality or corresponding functionality. In such embodiments, source device 12 or related functionality and destination device 14 or related functionality may be implemented using the same hardware and/or software, or using separate hardware and/or software, or any combination thereof.

As will be apparent to those skilled in the art based on the description, the existence and (exact) separation of functionality of various blocks or functions in source device 12 and/or destination device 14 as shown in FIG. 1 may differ depending on the actual device and implementation.

Encoder 20 (eg, video encoder 20) and decoder 30 (eg, video decoder 30) may each be implemented as any of a variety of suitable circuits, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware, or any combination thereof. If the methods are partially implemented in software, the device may store instructions for the software on a suitable non-volatile computer-readable storage medium and may execute the instructions in hardware using one or more processors to perform the methods of this invention. Any of the above (including hardware, software, a combination of hardware and software, etc.) may be considered one or more processors. Each of video encoder 20 and video decoder 30 may be contained in one or more encoders or decoders, each of which may be integrated as part of a combined encoder/decoder (CODEC) in a respective device.

2 shows a schematic/conceptual block diagram of an exemplary video encoder 20 that is configured to implement the methods of the present invention. In the example of FIG. 2, video encoder 20 comprises a residual calculation block 204, a transform processing block 206, a quantization block 208, an inverse quantization block 210 and an inverse transform processing block 212, a reconstruction block 214, a buffer 216, a loop filter block 220, a decoded buffer 230 images (DPB), block 260 processing prediction and block 270 entropy coding. The prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode select unit 262. Inter prediction block 244 may include a motion estimator and a motion compensation block (not shown). 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.

For example, the residual calculation block 204, the transform processing block 206, the quantization block 208, the prediction processing block 260, and the entropy encoding block 270 form a direct signal path of the encoder 20, while, for example, the inverse quantization block 210, the inverse transform processing block 212, block 214 recovery buffer 216, loop filter 220, decoded picture buffer (DPB) 230, prediction processing unit 260 form an encoder signal return path in which the encoder return signal path corresponds to the decoder signal path (see decoder 30 in FIG. 3).

Encoder 20 is configured to receive, for example, via input 202, image 201 or block 203 of image 201, for example, an image of a sequence of images constituting a video or video sequence. The image block 203 may also be referred to as the current image block or the image block to be encoded, and the image 201 as the current image or the image to be encoded (particularly in video encoding, to distinguish the current image from other images, such as previously encoded and /or decoded images of the same video sequence, i.e. a video sequence that also contains the current image).

The prediction processing unit 260, also referred to as the block prediction processing unit 260, is configured to receive or obtain a block 203 (the current block 203 of the current image 201) and reconstructed image data, such as reference samples of the same (current) image from the buffer 216 and /or reference picture data 231 from one or a plurality of previously decoded pictures from decoded picture buffer 230, and process the data for prediction, that is, to provide a prediction block 265, which may be an inter prediction block 245 or an intra prediction block 255.

Mode selector 262 may be configured to select a prediction mode (eg, intra or inter prediction mode) and/or a corresponding predictor 245 or 255 to be used as predictor 265 to calculate the residual block 205 and to reconstruct the reconstructed block 215 .

Embodiments of mode selector 262 may be configured to select a prediction mode (e.g., from those supported by prediction processor 260) that provides the best match, or in other words, minimum residual (minimum residual means better compression for transmission or storage) , or minimum signaling overhead (minimum signaling overhead means better compression for transmission or storage), or which takes into account or balances both. The mode selector 262 may be configured to determine a prediction mode based on rate distortion optimization (RDO), i.e., selection of a prediction mode that provides minimum rate distortion optimization, or which associated rate distortion at least satisfies the mode selection criteria. predictions.

The intra prediction block 254 is further configured to determine, based on the intra prediction parameter, for example, the selected intra prediction mode, the intra prediction block 255 . In any case, after selecting the block intra prediction mode, the intra prediction block 254 is also configured to provide an intra prediction parameter, that is, information indicative of the selected block intra prediction mode, to the entropy encoding block 270 . In one example, intra predictor 254 may be configured to perform any combination of the intra prediction methods described below.

3 shows an exemplary video decoder 30 that is configured to implement the methods of the present invention. Video decoder 30, configured to receive image encoding data (e.g., encoded bitstream) 21, for example, is encoded by encoder 100 to obtain decoded image 131. During the decoding process, video decoder 30 receives video data, for example, an encoded video bitstream that represents blocks encoded video segment images and associated syntax elements from video encoder 100.

In the example of FIG. 3, the decoder 30 includes an entropy decoding block 304, an inverse quantization block 310, an inverse transform processing block 312, a reconstruction block 314 (e.g., an adder 314), a buffer 316, a loop filter 320, a decoded picture buffer 330, and a block 360 prediction processing. The prediction processing block 360 may include an inter prediction block 344, an intra prediction block 354, and a mode selection block 362. Video decoder 30 may, in some examples, perform a decoding pass that is generally the reverse of the encoding step described with respect to video encoder 100 in FIG.

The entropy decoding unit 304 is configured to perform entropy decoding of the encoded image data 21 to obtain, for example, quantized coefficients 309 and/or decoded coding parameters (not shown in FIG. 3), for example, (decoded) any or all of the inter prediction parameters, parameter intra prediction, loop filter parameters, and/or other syntax elements. The entropy decoding block 304 is further configured to forward the inter prediction parameters, the intra prediction parameter, and/or other syntax elements to the prediction processing block 360 . Video decoder 30 may receive syntax elements at the video segment level and/or video block level.

Inverse quantizer 310 may be identical in function to inverse quantizer 110, inverse transform processor 312 may be identical in function to inverse transform processor 112, restorer 314 may be identical to restorer 114, buffer 316 may be identical to buffer 116 , the loop filter 320 may be identical in function to the loop filter 120, and the decoded image buffer 330 may be identical in function to the decoded image buffer 130.

Prediction processing block 360 may comprise inter prediction block 344 and intra prediction block 354, in which inter prediction block 344 may resemble inter function prediction block 144 and intra prediction block 354 may resemble intra function prediction block 154. Prediction processing unit 360 is typically configured to perform block prediction and/or obtain prediction block 365 from encoded data 21, and to receive or obtain (explicitly or implicitly) prediction-related parameters and/or selected prediction mode information, for example, from the block 304 entropy decoding.

When a video segment is encoded as an intra coding segment (I), the intra prediction block 354 of the prediction processing block 360 is configured to generate a prediction block 365 for the image block of the current video segment based on the signaled intra prediction mode and data from the previously decoded blocks of the current frame or picture. When a video frame is encoded as an inter-coded (i.e., B or P) segment, the inter prediction block 344 (e.g., motion compensation block) of the prediction processing block 360 is configured to generate a predictor 365 for the video block of the current video segment based on motion vectors and other elements. syntax received from block 304 entropy decoding. For inter prediction, prediction blocks may be obtained from one of the reference pictures in one of the reference picture lists. Video decoder 30 may construct reference frame lists, list 0 and list 1 using default construction methods based on reference pictures stored in DPB 330.

The prediction processing unit 360 is configured to determine prediction information for a video block of the current video segment by analyzing motion vectors and other syntax elements, and uses the prediction information to construct prediction blocks for the current video block being decoded. For example, prediction processing unit 360 uses some of the received syntax elements to determine the prediction mode (eg, intra or inter prediction) used to encode video blocks of a video segment, the type of inter prediction segment (eg, B-segment, P-segment, or GPB-segment ), one or more reference picture listing information for a segment, motion vectors for each inter-coded video block of the segment, inter-prediction status for each inter-coded video block of the segment, and other information for decoding video blocks in the current video segment.

The inverse quantizer 310 is configured to inverse quantize, that is, dequantize the quantized transform coefficients provided in the bitstream and decoded by the entropy decoder 304 . The inverse quantization process may include using a quantization parameter calculated by video encoder 100 for each video block in a video segment to determine the amount of quantization, and likewise, the amount of inverse quantization to be applied.

The inverse transform processing unit 312 is configured to apply an inverse transform, such as an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process, to the transform coefficients to obtain residual blocks in the pixel region.

Reconstructor 314 (e.g., adder 314) is configured to add inverse transform block 313 (i.e., reconstructed residual block 313) to prediction block 365 to obtain reconstructed block 315 in the sample area, for example, by adding sample values of the reconstructed residual block 313 and sample values of prediction block 365 .

The loop filter block 320 (either in the encoding loop or after the encoding loop) is configured to filter the reconstructed block 315 to obtain a filtered block 321, for example, to smooth pixel transitions or otherwise improve video quality. In one example, the loop filter unit 320 may be configured to perform any combination of the filtering methods described below. The loop filter block 320 is designed to represent one or more loop filters, such as a deblocking filter, an adaptive offset (SAO) filter, or other filters, such as a two-sided filter or an adaptive loop filter (ALF), or sharpening or anti-aliasing filters, or collaborative filters. Although the loop filter block 320 is shown in FIG. 3 as a loop filter, in other configurations, the loop filter block 320 may be implemented as a post-loop filter.

The decoded video blocks 321 in that frame or picture are then stored in the decoded picture buffer 330, which stores reference pictures used for subsequent motion compensation.

The decoder 30 is configured to output the decoded image 331, for example, through the output 332 for presentation or viewing to the user.

Other variants of video decoder 30 may be used to decode the compressed bitstream. For example, decoder 30 may generate an output video stream without loop filter block 320 . For example, non-transform decoder 30 may perform inverse quantization of the residual signal directly without inverse transform processing unit 312 for particular blocks or frames. In another implementation, video decoder 30 may have an inverse quantizer 310 and an inverse transform processor 312 combined into one block.

According to the HEVC/H.265 standard, 35 intra prediction modes are available. As shown in FIG. 4, this set contains the following modes: planar mode (intra prediction mode index is 0), DC mode (intra prediction mode index is 1), and directional (angular) modes that cover a range of 180° and have a range of values index of the intra prediction mode from 2 to 34, shown by black arrows in Fig.4. To capture arbitrary edge directions present in natural video, the number of directional intrinsic modes has been increased from 33, as used in HEVC, to 65. Additional directional modes are depicted by dotted arrows in FIG. 4, and planar mode and DC mode remain the same. It is worth noting that the range covered by the intra prediction modes may be wider than 180°. In particular, 62 directivity modes with index values from 3 to 64 cover a range of approximately 230°, i.e. several pairs of modes have opposite directions. In the case of the HEVC reference model (HM) and JEM platforms, only one pair of angle modes (namely, modes 2 and 66) has the opposite direction, as shown in FIG. To construct a predictor, conventional angular modes use reference samples and (if necessary) filter them to obtain a sample predictor. The number of reference samples required to construct a predictor depends on the length of the filter used for interpolation (for example, bilinear and cubic filters have lengths of 2 and 4, respectively).

VTM (Universal Test Model) uses 35 internal modes, while BMS (Background Set) uses 67 internal modes. To encode the 67 internal modes, the current internal mode coding scheme in BMS uses the following method:

In order to use an increased number of directional intra modes in the BMS, an intra mode coding method with 6 most likely modes (MPMs) is used. There are two main technical aspects involved here.

1) getting 6 MPMs, and

2) entropy coding of 6 MPMs and non-MPMs modes.

In BMS, the modes included in the MPM lists are divided into three groups: neighboring intrinsic modes, derived intrinsic modes, and default intrinsic modes.

The five adjacent intra prediction modes are used to build the MPM list. These 5 neighboring block locations are the same as those used in merge mode, i.e., left (L), top (A), bottom left (BL), top right (AR), and top left (AL) as shown in Fig.5. The initial MPM list is formed by inserting 5 adjacent internal modes, planar mode and DC mode into the MPM list. A pruning process is used to remove duplicate modes so that only unique modes are included in the MPM list. The order in which initial modes are added is: left, top, flat, DC, bottom left, top right, and top left.

If the MPM list is still incomplete (i.e. has less than 6 candidate MPMs in the list), the derived modes are added, these internal modes are obtained by adding -1 or +1 to the angular modes already included in the MPM list. The acquisition does not apply to non-angular modes, i.e. DC or planar.

Finally, if the MPM list is still incomplete, default modes are added in the following order: vertical, horizontal, inner mode 2, and diagonal mode. As a result of this process, a unique list of 6 MPM modes is generated.

For entropy encoding of 6 MPMs, a truncated unary binarization of MPMs is used. The first three bins are encoded with contexts that depend on the MPM mode associated with the bin that is currently being signaled. MPM mode is divided into one of three categories: (a) whether the mode belongs to horizontal (MPM mode is less than or equal to the diagonal direction), (b) vertical (MPM mode is greater than the diagonal direction), or (c) non-angular (DC and planar ) class. Accordingly, three contexts are used to signal the MPM index.

The remaining 61 non-MPMs are coded as follows. The 61 non-MPMs are first divided into two sets: a set of selected modes and a set of unselected modes. The set of selected modes contains 16 modes and the rest (45 modes) are assigned to the set of unselected modes. The set of modes to which the current mode belongs is indicated in the bitstream with a flag. The mode from the selected set is then signaled with a 4-bit fixed length code, and the mode from the unselected set is encoded with a truncated binary code. The selected set of modes is generated by sub-sampling a total of 61 non-MPMs with the following indices:

Set of selected modes = {0, 4, 8, 12, 16, 20… 60}

Set of unselected modes = {1, 2, 3, 5, 6, 7, 9, 10… 59}

Table 1 shows an overview of the various internal mode signaling mechanisms.

Table 1: signaling the current internal LUMA mode in the BMS

Intra prediction modes mrm flag Chosen Flag Bean string MRM modes (6) one 0 ten 110 1110 11110 11111 Selected modes (16) 0 one 4 bits fixed length code Unselected modes (45) 0 0 Truncated Binary

In another example, an intra mode encoding method with 3 most likely modes (MPMs) is used. In the example, the intra_luma_mpm_flag[x0][y0], intra_luma_mpm_idx[x0][y0], and intra_luma_mpm_remainder[x0][y0] syntax elements define the intra-prediction mode for luma samples. The array indices x0, y0 define the location (x0, y0) of the top left luma sample of the prediction block in question, relative to the top left luma sample of the image. When intra_luma_mpm_flag [x0] [y0] is equal to 1, an intra prediction mode is obtained from an adjacent intra prediction block.

Intraprediction for the current block (IntraPredModeY [xPb] [yPb]) is implemented using the following ordered steps:

Neighbor locations (xNbA, yNbA) and (xNbB, yNbB) are set to (xPb - 1, yPb) and (xPb, yPb - 1) respectively.

If X is replaced by either A or B, the candIntraPredModeX variables are output as follows:

The block availability determination process is triggered by a location (xCurr, yCurr) set to (xPb, yPb) and an adjacent location (xNbY, yNbY) set to (xNbX, yNbX) as input, and the output is availableX.

The intra prediction mode candidate candIntraPredModeX is obtained as follows:

If one or more of the following conditions are true, CandIntraPredModeX is set to INTRA_DC.

The availableX variable is FALSE.

CuPredMode [xNbX] [yNbX] is not equal to MODE_INTRA.

X is equal to B and yPb - 1 less than ((yPb >> CtbLog2SizeY) << CtbLog2SizeY).

Otherwise, CandIntraPredModeX is set to IntraPredModeY [xNbX] [yNbX].

CandModeList [x] with x = 0..2 is output like this:

If CandIntraPredModeB is equal to candIntraPredModeA, the following applies:

If candIntraPredModeA is less than 2 (i.e. equal to INTRA_PLANAR or INTRA_DC), candModeList[x] with x = 0..2 is output as follows:

candModeList[0] = INTRA_PLANAR

candModeList[1] = INTRA_DC

candModeList[2] = INTRA_ANGULAR50

Otherwise candModeList [x] with x = 0..2 is obtained like this:

candModeList[0] = candIntraPredModeA

candModeList[1] = 2 + ((candIntraPredModeA + 61) % 64)

candModeList[2] = 2 + ((candIntraPredModeA - 1) % 64)

Otherwise (candIntraPredModeB is not equal to candIntraPredModeA), the following applies:

CandModeList[0] and candModeList[1] are output like this:

candModeList[0] = candIntraPredModeA

candModeList[1] = candIntraPredModeB

If neither of candModeList[0] and candModeList[1] is INTRA_PLANAR, candModeList[2] is set to INTRA_PLANAR,

Otherwise, if neither of candModeList[0] and candModeList[1] is INTRA_DC, candModeList[2] is set to INTRA_DC,

Otherwise, candModeList[2] is set to INTRA_ANGULAR50.

IntraPredModeY [xPb] [yPb] is obtained by applying the following procedure:

If intra_luma_mpm_flag [xPb] [yPb] is 1, IntraPredModeY [xPb] [yPb] is set to candModeList [intra_luma_mpm_idx [xPb] [yPb]].

Otherwise, IntraPredModeY [xPb] [yPb] is obtained by performing the following ordered steps:

The array candModeList [x], x = 0..2 is modified by performing the following ordered steps:

When candModeList[0] is greater than candModeList[1], both values are swapped as follows:

(candModeList[0], candModeList[1]) = Swap(candModeList[0], candModeList[1])

When candModeList[0] is greater than candModeList[2], both values are swapped as follows:

(candModeList[0], candModeList[2]) = Swap(candModeList[0], candModeList[2])

When candModeList[1] is greater than candModeList[2], both values are swapped as follows:

(candModeList[1], candModeList[2]) = Swap(candModeList[1], candModeList[2]) (8 11)

IntraPredModeY [xPb] [yPb] is derived using the following ordered steps:

IntraPredModeY [xPb] [yPb] is set to intra_luma_mpm_remainder [xPb] [yPb].

For i equal to 0 to 2 inclusive, when IntraPredModeY [xPb] [yPb] is greater than or equal to candModeList [i], the value of IntraPredModeY [xPb] [yPb] is increased by one.

In one embodiment of the present invention, a frame is the same as an image.

In one aspect of the present invention, a method for constructing a most likely mode list, MPM, is disclosed, the method comprising:

determining whether the left block of the current coding block is available or not, if the left block of the current coding block is available, adding the left block intra prediction mode to the MPM list;

determining whether the top block of the current coding block is available or not, if the top block of the current coding block is available, adding the top block intra prediction mode to the MPM list;

if the planar mode is not in the MPM list, adding the planar mode to the MPM list;

if the DC mode is not in the MPM list, add the DC mode to the MPM list.

In one embodiment of the present invention, if the top block of the current coding block is available and the top block intra prediction mode is not contained in the MPM list, adding the top block intra prediction mode to the MPM list.

In one embodiment of the present invention, if the top block of the current coding block is available and the top block intra prediction mode is contained in the MPM list, "append" is performed, or we can say the result of the "append" process does not change the MPM list.

In one embodiment of the present invention, when the left block prediction mode is not an intra prediction mode, the left block of the current coding block is unavailable.

In one form of implementation of the present invention, when the current coding block is the coding block located at the very left of the frame, the left block of the current coding block is not available.

In one embodiment of the present invention in which parallel processing is supported and the current coding block is the coding block located at the very left of the tile, the left block of the current coding block is not available.

In one embodiment of the present invention in which parallel processing is not supported and the current coding block is the coding block located at the leftmost side of the tile but not the leftmost side of the frame, the left block of the current coding block is available.

In one embodiment of the present invention in which parallel processing is supported and the current coding block is the coding block located at the leftmost part of the segment, the left block of the current coding block is not available.

In one embodiment of the present invention in which parallel processing is not supported and the current coding block is the coding block located at the leftmost part of the segment, but not at the leftmost part of the frame, the left block of the current coding block is available.

In one embodiment of the present invention, when the top block prediction mode is not an intra prediction mode, the top block of the current coding block is not available.

In one form of implementation of the present invention, when the current coding block is the coding block located at the very top of the frame, the top block of the current coding block is not available.

In one embodiment of the present invention in which parallel processing is supported and the current coding block is the coding block located on the topmost side of the tile, the top block of the current coding block is not available.

In one embodiment of the present invention in which parallel processing is not supported and the current coding block is the coding block located on the topmost side of the tile but not the topmost side of the frame, the topmost block of the current coding block is available.

In one embodiment of the present invention in which parallel processing is supported and the current coding block is the coding block located at the very top of the segment, the top block of the current coding block is not available.

In one embodiment of the present invention in which parallel processing is not supported and the current coding block is the coding block located at the topmost part of the segment but not at the topmost part of the frame, the topmost block of the current coding block is available.

In one embodiment of the present invention, when the size of the linear buffer is limited and the current coding unit is the coding unit located on the topmost part of the current CTU, the top block of the current coding unit is not available.

In one form of implementation of the present invention, in which when the current coding block is a coding block not located in the leftmost part of the frame, the left block of the current coding block is available.

In one form of implementation of the present invention, in which when the current coding block is a coding block not located on the topmost part of the frame, the top block of the current coding block is available.

In one embodiment of the present invention, the method further comprises: if the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list, in which the intra prediction mode set contains vertical mode (VER_IDX) (as the first intra prediction mode), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX).

In one embodiment of the present invention, the method further comprises: adding vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) to the MPM list.

In one embodiment of the present invention, the method further comprises a corner mode candidate list comprising or consisting of: vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX) or diagonal mode (DIA_IDX ) in the MPM list; and the method further includes: iteratively determining, according to their order in the list, whether the list angular mode is in the MPM list, and if the corresponding angular mode is not in the MPM list, adding the corresponding angular mode to the MPM list.

In one form of implementation of the present invention, in which the construction of the MPM list begins with the step of determining whether the left block of the current coding block is available or not, for example, based on an empty MPM list.

In one form of implementation of the present invention, the method further comprises: if the left block of the current coding block is not available and another block in the general left direction is available (for example, BL or AL in Fig. 5), inserting the intra prediction mode of the other block in the MPM list, if the left a block is available without inserting another block's intra prediction mode into the MPM list.

In one form of implementation of the present invention, the method further comprises: if the top block of the current coding block is not available and another block in the general upstream direction (e.g., AR or AL in FIG. 5) is available, inserting the intra prediction mode of the other block into the MPM list if the top a block is available without inserting another block's intra prediction mode into the MPM list.

In one form of implementation of the present invention, the method further comprises: adding a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an internal mode 2 (2), a vertical diagonal mode (VDIA_IDX) or a diagonal mode (DIA_IDX) to the MPM list, if none in the MPM list.

In one embodiment of the present invention, the method further comprises:

if both the left and the top block of the current coding block are non-angular, one more neighboring block (eg, BL, AL, or AR in FIG. 5) is additionally checked. If any of them (BL, or AL, or AR) is angular, then use that angular mode as the initial angular mode for the -1 + 1 acquisition process, as described previously.

In one embodiment of the present invention, the value corresponding to VER_IDX is 50; the value corresponding to HOR_IDX is 18; the value corresponding to VDIA_IDX is 66, and this value may be the largest value of the values corresponding to the angular modes; value 2, which corresponds to the internal mode 2, may be the smallest value of the values corresponding to the angular modes; the value corresponding to DIA_IDX is 34.

In one embodiment of the present invention, if the number of intra prediction modes in the MPM list is less than a threshold, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not is contained in an MPM list in which the intra prediction mode set contains vertical mode (VER_IDX) (as the first intra prediction mode), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) .

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding an intra prediction mode to an intra prediction mode set containing vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2(2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) in accordance with the above order in the MPM list, when the intra prediction mode is not contained in the MPM list, as long as the number of prediction modes is equal to the threshold value.

In one embodiment of the present invention, the method further comprises:

if the left block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value,

checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list in which the intra prediction mode set contains the vertical mode (VER_IDX) ( as the first intra prediction mode), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX), or intra mode 2 (2).

In one embodiment of the present invention, the method further comprises:

if the left block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding to the MPM intra prediction mode list an intra prediction mode set containing vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX ) or intra mode 2 (2) in accordance with the above order, when the intra prediction mode is not included in the MPM list until the number of prediction modes becomes equal to a threshold value.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list, wherein the intra prediction mode set comprises a vertical mode (VER_IDX) (as the first intra prediction mode), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, or an intra prediction mode corresponding to VER_IDX with an offset of 4.

In one embodiment of the present invention, the intra prediction mode corresponding to VER_IDX with an offset of -4 uses the value corresponding to VER_IDX to add an offset of -4 and obtain the value of the corresponding intra prediction mode, for example, since the value of VER_IDX is 50, the intra prediction mode corresponding to VER_IDX with an offset of -4 is the intra prediction mode 46 , the intra prediction mode corresponding to VER_IDX with an offset of 4 is the intra prediction mode 54 . Other offset examples have processes similar to this example.

It should be noted that when performing -1 or +1 or other offset values, this may include an up and down transition operation, for example, since the value of the internal mode (2) is 2 (the smallest value in the values corresponding to the angular modes), then the internal mode (2)-1 will be 66 (up transition case) or, since the value of VDIA_IDX is 66 (the highest value in the values corresponding to angle modes), then VDIA_IDX +1 will be 2 (down transition case).

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold, iteratively adding an intra prediction mode to an intra prediction mode set containing a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, or an intra prediction mode corresponding to VER_IDX with an offset of 4, according to the above order for the MPM list, when the intra prediction mode is not contained in the MPM list, until the number of prediction modes becomes equal to the threshold value.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list, wherein the intra prediction mode set comprises a vertical mode (VER_IDX) (as the first intra prediction mode), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 4, or an intra prediction mode corresponding to VER_IDX with an offset of -4.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding an intra prediction mode to an intra prediction mode set containing a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 4, or an intra prediction mode, the corresponding VER_IDX with an offset of -4, in accordance with the above order for the MPM list, when the intra prediction mode is not contained in the MPM list, until the number of prediction modes becomes equal to the threshold value.

In one embodiment of the present invention, the method further comprises:

if the left block of the current coding block is not available and the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode not contained in the MPM list, in which the intra prediction mode set contains one of the following intra prediction mode sets:

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of 1; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of 4; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of -1; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of +1; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of -1; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of 1; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -4; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -4; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -1; or

a vertical mode (VER_IDX) (as the first intra prediction mode), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -1.

In one embodiment of the present invention, the method further comprises:

if the left block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding the intra prediction mode of the intra prediction mode set according to the above order in the MPM list, when the intra prediction mode is not contained in the MPM list, until until the number of prediction modes becomes equal to the threshold value;

wherein the intra prediction mode set contains one of the following intra prediction mode sets:

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of 1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of 4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of +1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of 1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -1.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than the threshold value, the top block of the current coding block is unavailable,

checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list in which the intra prediction mode set contains the horizontal mode (HOR_IDX) ( as the first intra prediction mode), intra mode 2 (2), diagonal mode (DIA_IDX), or vertical diagonal mode (VDIA_IDX).

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than the threshold value, the top block of the current coding block is unavailable,

iteratively adding an intra prediction mode to an intra prediction mode set containing a horizontal mode (HOR_IDX), an intra mode 2 (2), a diagonal mode (DIA_IDX), or a vertical diagonal mode (VDIA_IDX) according to the above order in the MPM list when the intra prediction mode is not is contained in the MPM list until the number of prediction modes becomes equal to the threshold value.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available,

checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list in which the intra prediction mode set contains the vertical mode (VER_IDX) ( as the first intra prediction mode), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX).

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available,

iteratively adding an intra prediction mode to an intra prediction mode set containing vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) according to the above order in the MPM list when the intra prediction mode is not included in the MPM list, until the number of prediction modes becomes equal to the threshold value.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than the threshold value, the top block of the current coding block is unavailable,

checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list in which the intra prediction mode set contains the horizontal mode (HOR_IDX) ( as the first intra prediction mode), intra mode 2 (2), diagonal mode (DIA_IDX), or vertical diagonal mode (VDIA_IDX).

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than the threshold value, the top block of the current coding block is unavailable,

iteratively adding an intra prediction mode to an intra prediction mode set containing a horizontal mode (HOR_IDX), an intra mode 2 (2), a diagonal mode (DIA_IDX), or a vertical diagonal mode (VDIA_IDX) according to the above order in the MPM list when the intra prediction mode is not is contained in the MPM list until the number of prediction modes becomes equal to the threshold value.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available,

checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list in which the intra prediction mode set contains the vertical mode (VER_IDX) ( as the first intra prediction mode), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, or an intra prediction mode corresponding to VER_IDX with an offset of 4.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available,

iteratively adding an intra prediction mode of an intra prediction mode set containing a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, or an intra prediction mode corresponding to VER_IDX with an offset of 4 according to the above order, in the MPM list when the intra prediction mode is not contained in the MPM list, until the number of prediction modes becomes equal to the threshold value.

In one embodiment of the present invention, the method further comprises:

if the top block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value,

checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list, in which the intra prediction mode set contains one of the following intra prediction mode sets predictions:

horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to HOR_IDX with an offset of 1; or

horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), intra prediction mode corresponding to HOR_IDX with offset -4, and HOR_IDX add offset 4; or

a horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 4, and an intra prediction mode corresponding to HOR_IDX with an offset of -1; or

a horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 4, and an intra prediction mode corresponding to HOR_IDX with an offset of 1; or

a horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 1, and an intra prediction mode corresponding to HOR_IDX with an offset of -1; or

a horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 1, and an intra prediction mode corresponding to HOR_IDX with an offset of 1; or

a horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to intra mode 2 (2) with an offset of 4; or

a horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to HOR_IDX with offset 1, and an intra prediction mode corresponding to intra mode 2 (2) with offset 4; or

a horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to intra mode 2 (2) with an offset of 1; or

a horizontal mode (HOR_IDX) (as the first intra prediction mode), intra mode 2 (2), an intra prediction mode corresponding to HOR_IDX with offset 1, and an intra prediction mode corresponding to intra mode 2 (2) with offset 1.

In one embodiment of the present invention, the method further comprises:

if the top block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value,

iteratively adding an intra prediction mode of the intra prediction mode set according to the above order in the MPM list when the intra prediction mode is not included in the MPM list until the number of prediction modes becomes equal to a threshold value;

wherein the intra prediction mode set contains one of the following intra prediction mode sets:

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to HOR_IDX with an offset of 1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to HOR_IDX with offset -4, and HOR_IDX add offset 4; or

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 4, and an intra prediction mode corresponding to HOR_IDX with an offset of -1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to intra mode 2 (2) with offset 4, and intra prediction mode corresponding to HOR_IDX with offset 1; or

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 1, and an intra prediction mode corresponding to HOR_IDX with an offset of -1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to intra mode 2 (2) with offset 1, and intra prediction mode corresponding to HOR_IDX with offset 1; or

a horizontal mode (HOR_IDX), intra mode 2(2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to intra mode 2(2) with an offset of 4; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to HOR_IDX with offset 1, and intra prediction mode corresponding to intra mode 2 (2) with offset 4; or

a horizontal mode (HOR_IDX), intra mode 2(2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to intra mode 2(2) with an offset of 1; or

horizontal mode (HOR_IDX), intra mode 2(2), intra prediction mode corresponding to HOR_IDX with offset 1, and intra prediction mode corresponding to intra mode 2(2) with offset 1.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding an intra prediction mode to an intra prediction mode set containing vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) in accordance with the above order in the MPM list, when the intra prediction mode is not contained in the MPM list, as long as the number of prediction modes is equal to the threshold value.

In one embodiment of the present invention, the method further comprises:

if the left block of the current coding block is not available and the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not included in the MPM list in which the intra prediction mode set contains vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX), or intra mode 2 (2).

In one embodiment of the present invention, the method further comprises: if the left block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding an intra prediction mode to an intra prediction mode set containing vertical mode (VER_IDX), vertical diagonal mode ( VDIA_IDX), diagonal mode (DIA_IDX), or intra mode 2 (2) according to the above order in the MPM list, when the intra prediction mode is not included in the MPM list until the number of prediction modes becomes equal to a threshold.

In one embodiment of the present invention, it can be understood that adding an intra prediction mode to the MPM list adds a value corresponding to the intra prediction mode to the MPM list.

In one embodiment of the present invention, the threshold value is 6.

In one implementation form of the present invention, the method further comprises: if the left block of the current coding block is available and the left block intra prediction mode is an angle mode, adding an offset to the left block prediction mode to obtain a new prediction mode, if the new prediction mode is not in the MPM list, adding new prediction mode in MPM list.

In the example, the offset is -1; in another example, the offset is 1. In some examples, the offset may be 2 or -2.

In one implementation of the present invention, the method further comprises: if the top block of the current coding block is available and the top block intra prediction mode is corner mode, adding an offset to the top block prediction mode to obtain the upshift prediction mode if the upshift prediction mode is not in the MPM list , adding to the MPM upshift prediction mode list.

In the example, the offset is -1; in another example, the offset is 1. In some examples, the offset may be 2 or -2.

In one aspect of the present invention, for performing the above methods, the encoder comprises a processing circuit.

In one aspect of the present invention, for performing the above methods, the decoder comprises a processing circuit.

In one aspect of the present invention, for performing the above methods, the computer program product comprises program code.

In one aspect of the present invention, a decoder for listing the most likely mode, MPM, comprising: one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, the programs, when executed by the processors, configuring the decoder to perform the above methods.

In one aspect of the present invention, an encoder for listing the most likely mode, MPM, comprises: one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, the programs, when executed by the processors, configuring the encoder to perform the above methods.

In the example,

First step: determining if the left block of the current encoding block is available or not.

If the left block of the current coding block is available, adding the left block intra prediction mode to the MPM list. The MPM list may be an empty list, if the left block of the current coding block is available, the left block intra prediction mode is added to the MPM list, then the MPM list includes one intra prediction mode; and, if the left block of the current coding block is not available, the MPM list is still an empty list after the first step.

Second step: determining whether the top block of the current coding block is available or not.

If the top block of the current coding block is available, adding the top block intra prediction mode to the MPM list. The MPM list may include a left block intra prediction mode, or an empty list as yet.

If the top block of the current coding block is available and the MPM list includes the intra prediction mode of the left block, it is additionally necessary to determine whether the intra prediction mode of the top block is the same as the intra prediction mode of the left block, if they are the same, the result of the step "add mode top block intra prediction in MPM list" does not change the number of intra prediction modes in the MPM list, the MPM list includes only one intra prediction mode; if the intra prediction mode of the top block is not the same as the intra prediction mode of the left block, then adding the intra prediction mode of the top block to the MPM list, and then the MPM list includes two intra prediction modes.

If the top block of the current coding block is available and the MPM list is still an empty list, adding the top block intra prediction mode to the MPM list, the MPM list includes only one intra prediction mode.

If the top block of the current coding block is not available and the MPM list includes the left block intra prediction mode, the MPM list will still only include the left block intra prediction mode.

If the top block of the current coding block is not available and the MPM list is still an empty list, the MPM list will still be an empty list.

Third step: if the planar mode is not in the MPM list, add the planar mode to the MPM list.

If after the second stage the MPM list does not include a planar mode, then adding the planar mode to the MPM list.

If both the left block intra prediction mode and the top block intra prediction mode are not available, or the available intra prediction mode is not a planar mode, the MPM list does not include a planar mode.

If the MPM list includes planar mode, you must go to the fourth step.

Fourth step: if the DC mode is not in the MPM list, add the DC mode to the MPM list.

If after the second stage or the third stage the MPM list does not include the DC mode, then it is necessary to add the DC mode to the MPM list.

If both the left block intra prediction mode and the top block intra prediction mode are not available, or the available intra prediction mode is not a DC mode, the MPM list does not include the DC mode.

If the DC mode is in the MPM list, you must proceed to the next steps or finish building the MPM list.

In one embodiment of the present invention, at each step in the process of adding a prediction mode to an MPM list, it is necessary to ensure that there are no duplicate prediction modes in the MPM list. Therefore, if the intra prediction mode to be added to the MPM list is the same as one intra prediction mode in the MPM list, the "add" process does not change the MPM list or the "add" process is not performed.

In one form of implementation of the present invention, after the 4th step only in the presence of angular mode, angular-1, angular + 1 are executed.

In the example, if the number of intra prediction modes in the MPM list is six. After the fourth stage, there are three cases regarding the length of the MPM:

Case 1: MPM length is 2: → both L and A are not angular (> DC) or not available, only planar and DC → use all four default modes.

Case 2: MPM length is 3: → one of L and A is angular, or they are the same angular. → use one default mode.

Case 3: MPM length is 4: → both L and A are angular and they are different → default mode is not used, since at least one of L-1, L + 1 will be added. If one of them is a duplicate of the top ( diff (L-A) = 1), then at least one of A-1 and A + 1 will be inserted additionally.

In one form of implementation of the present invention, the method further comprises: if the left block of the current coding block is available and the intra prediction mode of the left block is corner mode, adding an offset to the left block prediction mode to obtain a new prediction mode, if the new prediction mode is not in the MPM list, adding a new prediction mode to the MPM list.

In another example, the MPM list includes six intra prediction modes, since at best the above four stages could only obtain four intra prediction modes. The method further comprises:

Fifth step: if the left block of the current coding block is available and the intra prediction mode of the left block is the angular mode, adding an offset to the left block prediction mode to obtain a new prediction mode, and if the new prediction mode of the prediction mode is not in the MPM list, adding a new prediction mode to mpm list.

For example, if the left block of the current coding block is angular mode 27 (the value corresponding to this angular intra prediction mode is 27), and the MPM list after the above four steps is (27, 15, 0, 1). Adding an offset to the left block prediction mode to obtain a new prediction mode, if the new prediction mode is not in the MPM list, adding the new prediction mode to the MPM list. In the example, the offset is -1, so the new prediction mode is 26 and the updated MPM list is (27, 15, 0, 1, 26). In another example, the offset is 1, so the new prediction mode is 28 and the updated MPM list is (27, 15, 0, 1, 28). In another example, in the fifth step, one can add two offsets to the left block intra prediction mode, first add -1 and then add 1, or first add 1 and then add -1, so the updated MPM list can be (27, 15, 0, 1 , 26, 28) or (27, 15, 0, 1, 28, 26).

After the fifth step, check if the MPM list is full (if the number of intra prediction modes in the MPM list is equal to the threshold value, for example, the threshold value is 6, then the MPM list is full. If the number of intra prediction modes in the MPM list is less than the threshold value, then the MPM list not complete). If the MPM list is full, stop building the MPM list; if the MPM list is not complete, proceed to the next steps.

And, if the left block of the current coding block is not available, the fifth step is not performed and proceed to the next steps.

It should be noted that when adding an offset (e.g. -1 or +1) to the angular prediction mode, it may include a transition up and down operation, for example, if the angular prediction mode angularLeft is 2, then angularLeft -1 will be 66 (the case of transition up ) or if angularLeft is 66 then angularLeft + 1 will be 2 (case of transition down).

In one embodiment of the present invention, the method further comprises: if the top block of the current coding block is available and the top block intra prediction mode is corner mode, adding an offset to the top block prediction mode to obtain an upshift prediction mode if there is no upshift prediction mode in the MPM list, adding the upshift prediction mode to the MPM list.

In one example, the method further comprises:

Sixth step: if the top block of the current coding block is available and the intra prediction mode of the top block is the corner mode, adding an offset to the top block prediction mode to obtain the upshift prediction mode, and if the upshift prediction mode is not in the MPM list, adding a new mode predictions in the MPM list.

For example, if the top block of the current coding block is angle mode 26 (the value corresponding to this intra prediction angle mode is 26) and the MPM list after the aforementioned fifth step is (27, 26, 0, 1, 28). Adding an offset to the left block prediction mode to obtain the upshift prediction mode, if the upshift prediction mode is not in the MPM list, adding the upshift prediction mode to the MPM list. In the example, the offset is -1, so the upshift prediction mode is 25, the updated MPM list is (27, 26, 0, 1, 28, 25). In another example, the offset is 1, so the upshift prediction mode is 27, and insertion of upshift mode 27 is blocked because mode 27 has been inserted. In another example, in the sixth step, two offsets can be added to the upper block intra prediction mode, first adding -1 and then adding 1, or adding 1 first and then adding -1 if the MPM list is still empty after adding one offset.

And, if the top block of the current coding block is not available, the sixth step is not performed and proceeds to the next steps. After the sixth step, it is necessary to check if the MPM list is full (the number of intra prediction modes in the MPM list is 6). If the MPM list is full, stop building the MPM list; if the MPM list is empty (the number of intra prediction modes in the MPM list is less than 6), go to the next steps.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value (eg, the threshold value is 6), use the default list to compile the MPM list.

In the example, if the number of intra prediction modes in the MPM list is less than a threshold value, the default list contains vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) .

In the example, if the number of intra prediction modes in the MPM list is less than a threshold value, the list defaults to vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX add offset -4, or VER_IDX add offset 4.

In the example, if the number of intra prediction modes in the MPM list is less than a threshold, the list defaults to vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX add offset 4, or VER_IDX add offset -4.

In the example, if the left block of the current coding block is not available and the number of intra prediction modes in the MPM list is less than a threshold value, the default list contains:

vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX), or internal mode 2 (2); or

vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), VER_IDX add offset -1, VER_IDX add offset 1; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VER_IDX add offset -4, VER_IDX add offset 4; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VDIA_IDX add offset -4, VER_IDX add offset -1; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VDIA_IDX add offset -4, VER_IDX add offset +1; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VDIA_IDX add offset -1, VER_IDX add offset -1; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VDIA_IDX add offset -1, VER_IDX add offset 1; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VER_IDX add offset -1, VDIA_IDX add offset -4; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VER_IDX add offset 1, VDIA_IDX add offset -4; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VER_IDX add offset -1, VDIA_IDX add offset -1; or

vertical modes (VER_IDX), vertical diagonal mode (VDIA_IDX), VER_IDX add offset 1, VDIA_IDX add offset -1.

In the example, if the number of intra prediction modes in the MPM list is less than a threshold value, the top block of the current coding block is not available, the default list contains:

horizontal mode (HOR_IDX), internal mode 2 (2), diagonal mode (DIA_IDX), or vertical diagonal mode (VDIA_IDX).

In the example, if the number of intra prediction modes in the MPM list is less than a threshold, the left block of the current coding block is available, and the top block of the current coding block is available, the default list contains:

vertical mode (VER_IDX), horizontal mode (HOR_IDX), indoor mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX); or

vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX add offset -4 or VER_IDX add offset 4; or

vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX add offset 4 or VER_IDX add offset -4.

In one example, if the number of intra prediction modes in the MPM list is less than a threshold and the top block of the current coding block is not available, the default list contains:

horizontal mode (HOR_IDX), internal mode 2 (2), HOR_IDX add offset -1, HOR_IDX add offset 1; or

horizontal modes (HOR_IDX), internal mode 2 (2), HOR_IDX add offset -4, HOR_IDX add offset 4; or

horizontal modes (HOR_IDX), internal mode 2 (2), internal mode 2 (2) add offset 4, HOR_IDX add offset -1; or

horizontal modes (HOR_IDX), internal mode 2 (2), internal mode 2 (2) add offset 4, HOR_IDX add offset 1; or

horizontal modes (HOR_IDX), internal mode 2 (2), internal mode 2 (2) add offset 1, HOR_IDX add offset -1; or

horizontal modes (HOR_IDX), internal mode 2 (2), internal mode 2 (2) add offset 1, HOR_IDX add offset 1; or

horizontal modes (HOR_IDX), internal mode 2 (2), HOR_IDX add offset -1, internal mode 2 (2) add offset 4; or

horizontal modes (HOR_IDX), internal mode 2 (2), HOR_IDX add offset 1, internal mode 2 (2) add offset 4; or

horizontal modes (HOR_IDX), internal mode 2 (2), HOR_IDX add offset -1, internal mode 2 (2) add offset 1; or

horizontal modes (HOR_IDX), internal mode 2 (2), HOR_IDX add offset 1, internal mode 2 (2) add offset 1.

In one embodiment of the present invention, when the left block of the current coding block is not available, the top block of the current coding block may or may not be available.

In one embodiment of the present invention, when the top block of the current coding block is not available, the left block of the current coding block may or may not be available.

In one embodiment of the present invention, the method further comprises: adding a list of vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) to the MPM.

In one embodiment of the present invention, the method further comprises: if the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not included in the MPM list, in which the intra prediction mode set contains vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX).

In one embodiment of the present invention, the method further comprises: if the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding an intra prediction mode to an intra prediction mode set containing vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2 ), vertical diagonal mode (VDIA_IDX) or diagonal mode (DIA_IDX) according to the above order in the MPM list, when the intra prediction mode is not in the MPM list, until the number of prediction modes becomes equal to the threshold value.

In the example after the sixth step, if the MPM list is still empty (the number of intra prediction modes in the MPM list is less than the threshold value), orderly adding the intra prediction mode to the default mode list in the MPM list if that mode or those modes are not in the MPM list , repeat this step until the MPM list is full.

Seventh step: adding vertical mode (VER_IDX), horizontal mode (HOR_IDX), indoor mode 2 (2), vertical diagonal mode (VDIA_IDX) or diagonal mode (DIA_IDX) to the MPM list.

For example, if there is no vertical mode in the MPM list and the MPM list is not complete, add the vertical mode to the MPM list, if the MPM list is full after adding the vertical mode, finish building the MPM list.

And, if the MPM list is still empty after adding the vertical mode, check for horizontal mode in the MPM list. If horizontal mode is in the MPM list, additionally check if internal mode 2 is in the MPM list; if there is no horizontal mode in the MPM list, add the horizontal mode to the MPM list. Repeat this step until the MPM list is full.

In one form of implementation of the present invention in the seventh step with default mode lists, each insertion of a default mode into the MPM list must ensure that there is no duplicate mode. If the insert was successful, another check is performed to determine if the MPM list is complete. If yes, then the MPM building process stops; otherwise, continue pasting with a different default mode in that order.

In one embodiment of the present invention, the method further comprises: if the left block of the current coding block is not available and the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode prediction in the MPM list if the first intra prediction mode is not contained in the MPM list, in which the intra prediction mode set contains vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX), or intra mode 2 (2).

In one embodiment of the present invention, the method further comprises:

if the left block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding to the MPM intra prediction mode list an intra prediction mode set containing vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX ) or intra mode 2 (2) in accordance with the above order, when the intra prediction mode is not included in the MPM list until the number of prediction modes becomes equal to a threshold value.

In the example after the sixth step, if the MPM list is still empty and the left block of the current coding block is not available, add the intra prediction mode to the default mode list in the MPM list in order, if this mode or these modes are not in the MPM list, repeat this step until until the MPM list is full.

Seventh step: adding vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX) or internal mode 2 (2) list to MPM.

For example, if there is no vertical mode in the MPM list and the MPM list is not complete, add the vertical mode to the MPM list, if the MPM list is full after adding the vertical mode, finish building the MPM list.

And, if the MPM list is still empty after adding the vertical mode, check for vertical diagonal mode in the MPM list. If the vertical diagonal mode is in the MPM list, additionally check if the diagonal mode is in the MPM list; if the diagonal mode is not in the MPM list, add the diagonal mode to the MPM list. Repeat this step iteratively until the MPM list is full.

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the upper block of the current coding block is unavailable, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list, if the first intra prediction mode is not included in the MPM list, in which the intra prediction mode set contains horizontal mode (HOR_IDX), intra mode 2 (2), diagonal mode (DIA_IDX), or vertical diagonal mode (VDIA_IDX).

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the top block of the current coding block is unavailable, iteratively adding an intra prediction mode to an intra prediction mode set containing horizontal mode (HOR_IDX), intra mode 2(2), diagonal mode (DIA_IDX), or vertical diagonal mode (VDIA_IDX) in accordance with the above order in the MPM list, when the intra prediction mode is not contained in the MPM list until the number of prediction modes becomes equal to the threshold value.

In the example, after the sixth step, if the MPM list is still not filled, the top block of the current coding block is not available, add the intra prediction mode to the default mode list in the MPM list in order, if this mode or these modes are not in the MPM list, repeat this step iteratively until the MPM list is full.

Step 7: Add Horizontal Mode (HOR_IDX), Inner Mode 2 (2), Diagonal Mode (DIA_IDX), or Vertical Diagonal Mode (VDIA_IDX) to the MPM list.

For example, if the horizontal mode is not in the MPM list and the MPM list is not complete, add the horizontal mode to the MPM list, if the MPM list is full after adding the horizontal mode, finish building the MPM list.

And, if the MPM list is still empty after adding horizontal mode to the MPM list, check for internal mode 2. If internal mode 2 is in the MPM list, additionally check for diagonal mode in the MPM list; if the diagonal mode is not in the MPM list, add the diagonal mode to the MPM list. Iteratively repeat this step until the MPM list is full.

In one implementation form of the present invention, the method further comprises: if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available, checking if the first intra prediction mode of the intra prediction mode set is contained in MPM list, and adding the first intra prediction mode to the MPM list, if the first intra prediction mode is not contained in the MPM list, in which the intra prediction mode set contains vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX) or diagonal mode (DIA_IDX).

In one embodiment of the present invention, the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available, iteratively adding to the MPM intra prediction mode list a set of intra prediction modes including vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX) or diagonal mode ( DIA_IDX) according to the above order when the intra prediction mode is not included in the MPM list, as long as the number of prediction modes is not becomes equal to the threshold value.

In the example, after the sixth step, if the MPM list is still empty, the left block of the current coding block is available and the top block of the current coding block is also available, add the default intra prediction mode to the MPM list if that mode or these modes are not in the MPM list , iteratively repeat this step until the MPM list is full.

Step 7: Add Vertical Mode (VER_IDX), Horizontal Mode (HOR_IDX), Inner Mode 2 (2), Vertical Diagonal Mode (VDIA_IDX) or Diagonal Mode (DIA_IDX) to the MPM list.

For example, if there is no vertical mode in the MPM list and the MPM list is not complete, add the vertical mode to the MPM list, if the MPM list is full after adding the vertical mode, finish building the MPM list.

And, if the MPM list is still empty after adding the vertical mode, check for horizontal mode in the MPM list. If horizontal mode is in the MPM list, additionally check if internal mode 2 is in the MPM list; if internal mode 2 is not in the MPM list, add internal mode 2 to the MPM list. Iteratively repeat this step until the MPM list is full.

In one embodiment of the present invention, the method further comprises: adding vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX adding offset -4, or VER_IDX adding offset 4 to the MPM list.

In one embodiment of the present invention, the method further comprises: adding vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX adding offset 4, or VER_IDX adding offset -4 to the MPM list.

In the example after the sixth step, if the MPM list is still incomplete, add the intra prediction mode to the default mode list in the MPM list, if this mode or these modes are not in the MPM list, iteratively repeat this step until the MPM list is will be full.

Seventh step: add to MPM list vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX add offset -4 or VER_IDX add offset 4; or adding vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX adding offset 4, or VER_IDX adding offset -4 to the MPM list.

For example, if there is no vertical mode in the MPM list and the MPM list is not complete, add the vertical mode to the MPM list, if the MPM list is full after adding the vertical mode, finish building the MPM list.

And, if the MPM list is still empty after adding the vertical mode, check for horizontal mode in the MPM list. If the horizontal mode is in the MPM list, additionally check if there is a prediction mode whose value is equal to the value of VER_IDX, add an offset of -4 to the MPM list; if the prediction mode whose value is equal to the value of VER_IDX, add offset -4, is not in the MPM list, add the prediction mode whose value is equal to the value of VER_IDX, add offset -4 to the MPM list. Iteratively repeat this step until the MPM list is full.

In the example after the sixth step, if the MPM list is still empty and the left block of the current coding block is not available, add the intra prediction mode to the default mode list in the MPM list, if this mode or these modes are not in the MPM list, iteratively repeat this step, until the MPM list is full.

Seventh step: add vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX) or internal mode 2 (2) to the MPM list.

For example, if there is no vertical mode in the MPM list and the MPM list is not complete, add the vertical mode to the MPM list, if the MPM list is full after adding the vertical mode, finish building the MPM list.

And if the MPM list is still empty after adding the vertical mode, check for vertical diagonal mode in the MPM list. If the vertical diagonal mode is in the MPM list, additionally check if the diagonal mode is in the MPM list; if the diagonal mode is not in the MPM list, add the diagonal mode to the MPM list. Iteratively execute this step until the MPM list is full.

In the example after the sixth step, if the MPM list is still empty, the top block of the current coding block is not available, add the intra prediction mode to the default mode list in the MPM list, if this mode or these modes are not in the MPM list, iteratively execute this step until the MPM list is full.

Step 7: Add Horizontal Mode (HOR_IDX), Inner Mode 2 (2), Diagonal Mode (DIA_IDX), or Vertical Diagonal Mode (VDIA_IDX) to the MPM list.

For example, if the horizontal mode is not in the MPM list and the MPM list is not complete, add the horizontal mode to the MPM list; if the MPM list is full after adding the horizontal mode, finish building the MPM list.

And, if the MPM list is still empty after adding the horizontal mode, check for internal mode 2 in the MPM list. If internal mode 2 is in the MPM list, additionally check for diagonal mode in the MPM list; if the diagonal mode is not in the MPM list, add the diagonal mode to the MPM list. Iteratively execute this step until the MPM list is full.

In the example after the sixth step, if the MPM list is still empty, the left block of the current coding block is available, and the top block of the current coding block is available, add to the MPM list the intra prediction mode in the default mode, if this mode or these modes are not present in the MPM list, iteratively execute the step until the MPM list is full.

Seventh step: add vertical mode (VER_IDX), horizontal mode (HOR_IDX), VER_IDX add offset -4 or VER_IDX add offset 4 to MPM list.

In the example for building the MPM list, predefined default modes are provided: namely, vertical mode (VER_IDX), horizontal mode (HOR_IDX), inner mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) if it is not complete. Two additional approaches to these default modes are proposed. They are the default adaptive approach and the modified default approach.

The adaptive modes approach considers blocks that are located at the very left and at the very top of the frame. For blocks located on the left frame boundary, horizontal mode is unlikely to be used, since there are no original prediction samples located in the left block of the current block. In addition, modes that normally use horizontal modes (eg, DIA_IDX, mode 2) are considered unlikely.

For blocks located at the top of the frame, vertical mode is unlikely because the original prediction samples that are in the top block of the current block are not present. Also, modes that typically use vertical modes (eg, VDIA_IDX, DIA_IDX) are unlikely.

Therefore, the following approach is used, taking into account the boundaries:

If the left block of the current coding block is missing, then the following sequence of modes is used as default mode candidates: VER_IDX, VDIA_IDX, DIA_IDX, mode 2.

Otherwise (if there is a left block):

if the top block of the current coding block is missing, then the following modes are used in order as default mode candidates: HOR_IDX, mode 2, DIA_IDX, VDIA_IDX.

Otherwise (if there is a top block), use the normal default modes: VER_IDX, HOR_IDX, internal mode 2(2), VDIA_IDX, or DIA_IDX

The modified default approach adds the following mode candidates to the MPM list: VER, HOR, VER-4, VER+4. The sequence VER-4, VER+4 can be changed.

One combination of these two methods may be as follows:

If the left block of the current coding block is missing, then the following modes are used in order as default mode candidates: VER_IDX, VDIA_IDX, DIA_IDX, mode 2.

Otherwise (if there is a left block):

if the top block of the current coding block is missing, then the following modes are used in order as default mode candidates: HOR_IDX, mode 2, DIA_IDX, VDIA_IDX.

Otherwise (if there is a top block), use modified default modes: VER_IDX, HOR_IDX, VER, HOR, VER-4, VER+4.

In one aspect of the present invention, a simplified method for constructing a 6-entry MPM list is provided, comprising: checking the availability of the left block of the current coding block. The position of the left block is shown in figure 5, where the left block is indicated by the letter "L".

The left block is unavailable in the absence of intra prediction information (ie, intra prediction mode) from the left block. Which includes the following cases:

the left block is not an intra prediction block; there is no left block, for example, the current block is a coding block located at the very left of the frame; if the encoder or decoder supports parallel processing, the left block can be considered missing (or inaccessible) if located in different tiles of the current block or with the current block, i.e. the current coding block is or is located on the leftmost side of the tile.

In another example, if parallel processing is not supported in the encoder or decoder, the left block may be considered available if it is located in different tiles of the current block, i.e., the current encoding block is on the leftmost side of the tile.

If parallel processing is supported in the encoder or decoder, the left block can be considered as missing if it is located in different segments from the current block, that is, the current encoding block is located in the leftmost part of the segment.

In another example, if parallel processing is not supported in the encoder or decoder, the left block may be considered available if it is located in different segments from the current block, i.e., the current encoding block is in the leftmost part of the segment.

Otherwise (i.e. left block available), include in the MPM list with 6 entries left block intra prediction mode.

Check the availability of the top block of the current coding block. The position of the top block is shown in Fig. 5 where the top block is labeled "A".

The top block is unavailable if no intra prediction information (ie, intra prediction mode) can be obtained from the top block. Which includes the following cases:

The top block is not an intra prediction block.

The top block is missing. For example, the current block is the coding block located at the very top of the frame.

If parallel processing is supported in the encoder or decoder, the top block can be considered missing if it is located in different tiles from the current block, that is, the current encoding block is at the very top of the tile.

In another example, if parallel processing is not supported in the encoder or decoder, the top block may be considered available if it is located in different tiles from the current block, that is, the current encoding block is located at the very top of the tile.

If parallel processing is supported in the encoder or decoder, the top block can be considered as missing if it is located in different segments from the current block, that is, the current encoding block is at the very top of the segment.

In another example, if parallel processing is not supported in the encoder or decoder, the top block may be considered available if it is located in different segments from the current block, ie. the current coding block is located at the very top of the segment.

If it is necessary to limit the size of the line buffer in the encoder or decoder, the top block may be considered absent if it is located in a different CTU with the current block, i.e., the current coding block is in the uppermost side of the current CTU.

In the example, if the decoder side or the encoder side supports the linear buffer constraint, then the upper block located on a different CTU with the current CTU is considered to be missing. If the linear buffer constraint is not supported, then its presence is considered.

Otherwise (that is, the left block is available), add the upper block intra-prediction mode to the MPM list with 6 entries.

Check if planar mode (PLANAR_IDX = 0) is inserted into the MPM list (i.e. check if the inner mode of the left and top block is planar mode) only if planar mode has not been inserted into the MPM list, then insert planar mode into MPM list. Check if the DC mode (DC_IDX = 1) has been inserted into the MPM list (i.e. check that the left and top block modes are DC modes), only if the DC mode has not been inserted into the MPM list, then insert the DC mode into the MPM list.

If the left block is available and if its intra-prediction mode is angular mode, i.e., (mode > DC_IDX and mode is angularLeft), get its two closest angular modes by doing angularLeft-1, angularLeft + 1. Note that when performing -1 or +1 may include a jump up and a jump down operation, for example,

If angularLeft is 2 then angularLeft-1 will be 66 (in case of transition up), or if angularLeft is 66 then angularLeft + 1 will be 2 (in case of transition down).

If the angularLeft-1 prediction mode was not inserted into the MPM list, insert it into the MPM list.

If the prediction mode angularLeft + 1 was not inserted into the MPM list, insert it into the MPM list.

If the MPM list is not complete and if the top block is available and if its intra-prediction mode is angular, i.e., (mode > DC_IDX and mode is angularAbove), get the two nearest angular modes by doing angularAbove-1, angularAbove+1. Note that when doing -1 or +1 this may include a move up and move down operation, in the example if angularLeft is 2 then angularLeft-1 will be 66 (case of move up) or if angularLeft is 66 then angularLeft +1 will be 2 (case of transition down).

If the angularAbove-1 prediction mode was not inserted into the MPM list, insert it into the MPM list.

If the MPM list is incomplete (for example, the number of prediction modes in the MPM list is less than 6) and if the prediction mode angularAbove + 1 was not inserted into the MPM list, insert it into the MPM list.

If the MPM list is empty, insert the following modes into the MPM list until it is full (for example, the number of prediction modes in the MPM list is 6):

vertical mode (VER_IDX),

horizontal mode (HOR_IDX),

internal mode 2 (2),

vertical diagonal mode (VDIA_IDX) or diagonal mode (DIA_IDX).

A summary of the variations of the proposed method:

The accessibility of the left block must take into account both support and non-support for parallel processing.

The accessibility of the top block should take into account both support and non-support for parallel processing.

The order of obtaining the two closest modes of the left and top block can also be first +1 and then -1.

The last candidate in the MPM list may be VIDA_IDX or DIA_IDX.

Insertion order can also be left, top, planar, DC, and default modes (VER_IDX, HOR_IDX, 2, VDIA_IDX, or DIA_IDX).

Truncated unary binarization is used to signal mpm_idx. The first three mpm_idx bins are allowed to use three different independent contexts, or all mpm_idx bins are encoded using CABAC.

The present invention is directed to an improvement in the intra mode signaling scheme. The present disclosure provides a video decoding method and a video decoder.

7 shows an example of 67 intra prediction modes, for example, as proposed for VVC, a plurality of intra prediction modes of 67 intra prediction modes containing: planar mode (index 0), DC mode (index 1), and angular modes with indices 2 to 66 , in which the lower left corner mode in FIG. 7 is at index 2, and the index numbering is incremented until index 66 becomes the uppermost right corner mode in FIG. 7.

In another aspect of the present invention, a decoder is disclosed, comprising a processing circuit configured to perform the above decoding methods.

In another aspect of the present invention, a computer program product is disclosed that contains program code for performing the above decoding methods.

In another aspect of the present invention, a decoder for decoding video data is disclosed, the decoder comprising: one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, the programs, when executed by the processors, configuring the decoder to perform the aforementioned decoding methods.

The processing circuitry may be implemented in hardware or a combination of hardware and software, such as a programmable processor or the like.

In another aspect of the present invention, an encoding method is disclosed which comprises:

obtaining an intra prediction mode of an image block from a set of intra prediction modes, a set of intra prediction modes for an image block contains a set of most probable modes, MPMs, and a set of non-MPMs, in which the set of non-MPMs contains a first set of intra prediction modes and a second set of intra prediction modes ;

if the intra prediction mode of the image block is in the set of non-MPMs, generating a mapping relationship between at least one intra prediction mode in the first set of intra prediction modes and at least one intra prediction mode in the set of non-MPMs;

encoding the intra prediction mode of the image block to obtain an intra prediction mode codeword according to the mapping relation.

In one form of implementation of the present invention, the process of obtaining the intra prediction mode of a picture block may refer to a relative disclosure in the following detailed description of a part of the embodiments, or a relative disclosure in the field of video coding technology, for example, in ITU-T H.264, ITU-T H. 265.

In one form of implementation of the present invention, the encoding method further comprises: generating a set of MPMs, determining whether the intra prediction mode of the image block is in the set of MPMs. Therefore, if the intra prediction mode of the image block is not in the set of MPMs, then the intra prediction mode of the image block is in the set of non-MPMs.

The process of generating a set of MPMs may refer to relative disclosure in the description part or relative disclosure in the field of video coding technology, for example, in ITU-T H.264, ITU-T H.265.

In one embodiment of the present invention, the process of generating a mapping relationship between at least one intra prediction mode in a first set of intra prediction modes and at least one intra prediction mode in a set of non-MPMs may refer to relative expansion on the decoding side.

In one embodiment of the present invention, the first set of intra prediction modes is encoded using 5 bits and the second set of intra prediction modes is encoded using 6 bits.

In another aspect of the present invention, an encoder is disclosed, comprising a processing circuit capable of performing the above encoding methods.

In another aspect of the present invention, a computer program product is disclosed that contains program code for performing the above encoding methods.

In another aspect of the present invention, an encoder for encoding video data is disclosed, the encoder comprising: one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, the programs, when executed by the processors, configuring the encoder to perform the aforementioned encoding methods.

The processing circuitry may be implemented in hardware or a combination of hardware and software, such as a programmable processor or the like.

In one form of implementation of the present invention according to Fig.8, the present invention provides a video decoding method that comprises:

S801: decoding encoded image block data to obtain an intra prediction mode from a plurality of intra prediction modes for the image block;

the set of intra prediction modes for an image block comprises a set of most likely modes, MPMs, and a set of non-MPMs, in which the set of non-MPMs contains a first set of intra prediction modes and a second set of intra prediction modes, in which the mode in the first set of intra prediction modes is encoded with using N bits, and the mode in the second set of intra prediction modes is encoded using M bits, N and M are positive integers, N is less than M,

wherein decoding the encoded image block data to obtain an intra prediction mode from a plurality of intra prediction modes for the image block (S801) comprises:

S802: decoding encoded data to obtain an indication indicating whether the intra prediction mode for the image block is in the set of MPMs or not; if the indication indicates that the intra prediction mode for the image block is not present in the set of MPMs,

S803: generating a mapping relationship between at least one intra prediction mode in the first intra prediction mode set and at least one intra prediction mode in the non-MPMs set;

S804: decoding the encoded data to obtain an intra prediction mode codeword for the image block;

S805: Obtaining the intra prediction mode for the image block according to the display ratio and the intra prediction mode codeword.

According to the video decoding method of the present invention, a truncated binarization scheme is used to encode prediction modes in a set of non-MPMs, and a mapping relation is generated, therefore, the prediction mode for the current block has a higher coding capability while using fewer bits, and the computational complexity on the decoder side is reduced.

In one form of implementation of the present invention according to Fig.9, the present invention provides a video decoding method comprising:

S901: receiving encoded picture block data;

The decoder side may be configured to receive the encoded image data via a direct link between the encoder side and the decoder side, such as a direct wired or wireless connection, or through any network, such as a wired or wireless network, or any combination thereof, or any private and public network, or any combination of them.

S902: decoding the encoded data to obtain an indication indicating whether the intra prediction mode for the image block is in the set of MPMs or not.

An indication indicating whether the intra prediction mode for the image block is in the MPMs set or not may be a flag, when the flag value is 1, may indicate that the intra prediction mode for the image block is in the MPMs set, when the flag value is 0, may indicate that there is no intra prediction mode for the image block in the set of MPMs. For example, on the encoder side, if the MPM list (set of MPMs) is a set of intrinsic modes, say [25, 42, 63] and the current value of the intrinsic mode of the blocks is 42, then the MPM flag indication is set to 1 as the intrinsic mode for the current block is in the second entry of the MPM list. If, for example, the current internal block mode is 41 instead of 42, then the MPM flag indication is set to 0, the MPM flag is sent to the decoding side in the encoded data.

If the indication indicates that the intra prediction mode for the image block is in the set of MPMs, execute step S903;

If the indication indicates that the intra prediction mode for the image block is in the set of MPMs, execute step S904;

S903: decoding the encoded data to obtain an intra prediction mode for the image block according to the set of MPMs;

In one example, if an indication indicating the intra prediction mode for an image block is in a set of MPMs. The output process for the block intra prediction mode (IntraPredModeY [xPb] [yPb]) of an image is defined as follows:

IntraPredModeY [xPb] [yPb] is obtained by applying the following procedure:

If intra_luma_mpm_flag [xPb] [yPb] is 1 (indicating that the intra prediction mode for the image block is in the MPM set), IntraPredModeY [xPb] [yPb] is set to candModeList [intra_luma_mpm_idx [xPb] [ yPb]], where (xPb , yPb) indicates the top left sample of the current luma prediction block relative to the top left luma sample of the current image, and candModeList is the actual MPM list, decoding the encoded data to obtain the MPM index, obtaining the intra prediction mode of the image block according to the MPM index and the MPM list.

In a specific example, the set of MPMs is (15, 0, 20), the index MPM value is 2, so the image block intra prediction mode is planar mode (value 0). In another specific example, the set of MPMs is (15, 36, 0, 1, 21, 19), the index MPM value is 5, so the intra prediction mode of the image block is angle mode 21.

S904: generating a mapping relationship between at least one intra prediction mode in the first set of intra prediction modes and at least one intra prediction mode in the set of non-MPMs;

In the example, if the indication indicates that the intra prediction mode for the image block is not included in the set of MPMs, two lists are compiled: namely, a list of codewords and a list of received modes.

The first list of code words is composed as follows:

1. Find the smallest mode in the MPM list, suppose the smallest mode is Ms.

2. Set the initial increment variable Inc = 1.

3. Set the candidate mode Mc as (Ms + Inc), check also the presence of the Mc mode in the MPM list.

If there is no Mc in the MPM list, add Mc to the codeword list otherwise go to step 4.

4. Check if the inserted entries in the list of codewords are full (the length of the insertion is equal to the length of the list of codewords):

If complete, terminate;

Otherwise, set Inc = Inc + 1 and go to step 3.

To summarize, the list of codewords will contain the smallest modes other than those in the MPM list. Given that the length of the MPM list is L, then the length of the codeword list is 64-(67-L) = L-3. For example, if the MPM list is (15, 36, 0, 1, 21, 19), then the constructed codeword will be (2, 3, 4).

The second list of received modes is compiled as follows:

1. Find the first two angular modes in the MPM list, assuming the ones found are angular0 and angular1.

2. Set the initial increment variable Inc = 1.

3. Get new mode M0 _minus = angular0 - Inc. It should be noted that M0 _minus must also guarantee the angular mode (ie 66>= M0 _minus >= 2). Therefore, if angular0 is 2, Inc is 1; then the resulting M0 _minus will be 66; if Inc is 2, then M0 _minus is 65, and so on. Operation "minus" is the transition up to the maximum angular mode.

4. Check the presence of M0 _minus in the MPM list, if not, and if the list of received modes is not complete, insert M0 _minus into the list of received modes. Otherwise,

If the list of received modes is complete, terminate.

Otherwise, go to step 5.

5. Get new mode M0 _plus = angular0 + Inc. Note. M0 _plus must also be provided with angle mode (ie 66 >= M0 _plus >= 2). Therefore, if angular0 is 66, Inc is 1, then the resulting value of M0 _plus will be 2. If Inc is 2, then M0 _plus will be 3, and so on. The "plus" operation is a transition down to the minimum angular mode.

6. Check the presence of M0 _plus in the MPM list, if not and if the list of received modes is not complete, insert M0 _plus into the list of received modes. Otherwise,

If the list of received modes is complete, terminate.

Otherwise, go to step 7.

7. Repeat steps 3-6, replacing angular0 with angular1.

8. Set Inc = Inc + 1 and repeat steps 3-7.

To sum up, the received mode list gets the neighboring modes of the first two angle modes in the MPM list. If these neighboring modes are already included in the MPM list, then they are excluded from the list of received modes. Considering that the length of the MPM list is L, the length of the received mode list is 64-(67-L)=L-3. For example, if the MPM list is (15, 36, 0, 1, 21, 19), then the constructed list of received modes is (14, 16, 35).

When the list of codewords and the list of received modes are built, a bidirectional mapping relationship is formed between them. Namely, given the above examples of lists with a list of codewords (2, 3, 4) and a list of received modes (14, 16, 35), 2←→14, 3←→16 and 3←→35, where ←→ represents bidirectional display.

Two variations are considered for constructing a bidirectional mapping relationship between a codeword list and a derived mode list. The first variation is that the list of received modes can be constructed in such a way that the list of received modes and the list of codewords can contain elements. Another variation is that the list of received modes cannot overlap with the modes in the codeword list.

In another example, in one embodiment of the present invention, wherein generating a mapping relationship between at least one intra prediction mode in a first set of intra prediction modes and at least one intra prediction mode in a set of non-MPMs comprises: ranking a plurality of intra prediction mode categories according to the number and/or direction of intra prediction modes in the MPM set falling into each intra prediction mode category; generating a display relation according to the category of the intra prediction mode with the highest rank.

In the example, there are 5 categories of the angular intra prediction mode, namely, DC mode (DC_IDX), vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), and diagonal mode DIA_IDX, in which the most likely list angular intra prediction mode falling into each category of the angular intra prediction mode, for example, corresponds to associating each of the angular intra prediction modes of the most likely modes list with an angular intra prediction mode category closest to the corresponding angular intra prediction mode of the most likely list modes. In another example, repeating this step with the second highest category of the angular intra prediction mode.

In an example, generating a mapping relationship between at least one intra prediction mode in the first intra prediction mode set and at least one intra prediction mode in the non-MPMs set comprises: generating an initial intra prediction mode set according to the addition of an offset to a set of values corresponding to a set of MPMs; classifying the set of MPMs to obtain the highest ranked intra prediction mode category; generating a mapping relationship according to the highest ranking intra prediction mode category and the initial set of intra prediction modes.

In the example, an initial set of intra prediction modes is generated according to adding an offset of -1, +1, +2, -2, +3, -3, +4, or -4 to the set of values corresponding to the set of MPMs.

The example generates display relationships according to a predefined default mode list containing or consisting of planar mode (PLANAR_IDX), DC mode (DC_IDX), vertical mode (VER_IDX), horizontal mode (HOR_IDX), indoor mode 2(2), vertical diagonal mode (VDIA_IDX) and diagonal mode (DIA_IDX).

S905: decoding the encoded data to obtain an intra prediction mode codeword for the image block;

the codeword is encoded using N bits or M bits on the encoded side. In one example, since this is a bidirectional mapping relationship, the intra prediction mode corresponding to the codeword may be mapped to another intra prediction mode in a set of non-MPMs.

S906: Obtaining the intra prediction mode for the image block according to the mapping ratio and the intra prediction mode codeword.

In the example, after constructing the bidirectional mapping relation, checking if the intra prediction mode corresponding to the intra prediction mode codeword is in the codeword list or the received mode list:

If the parsed intra prediction mode is not in either the codeword list or the received modes list, set the final prediction mode as the parsed intra prediction mode.

If the parsed intra prediction mode is only in the codeword list or only in the received mode list, then set the final prediction mode as corresponding to the mapped intra prediction mode.

If the parsed intra prediction mode is present in both the codeword list and the received mode list, a mechanism is introduced into the construction of the two lists so that the bidirectional mapping relationship is corrected and all overlapping modes are mapped onto themselves in the other list. Example: MPM list (0 1 2 3 50 66), codeword list (4 5 6), received mode list (4 65 5). When constructing a list of received modes or a list of code words, it is necessary to provide 4←→4, 5←→5 and 6←→65.

A decoder containing a processing circuit configured to perform the above methods.

The present disclosure discloses a computer program product containing program code for performing the above methods.

The present disclosure discloses a decoder for decoding video data, the decoder comprising: one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, the programs, when executed by the processors, configuring the decoder to perform the above methods.

7 shows an example of 67 intra prediction modes, for example, as proposed for VVC, in which a plurality of intra prediction modes of the 67 intra prediction modes comprise: planar mode (index 0), DC mode (index 1), and angular modes with indices 2- 66, in which the lower left corner mode in FIG. 7 is at index 2, and the index numbering is incremented until index 66 is the top right corner mode in FIG.

Further embodiments are disclosed in which the numbering may not necessarily be the same as the numbering of other embodiments or examples of the description.

Option 1 implementation. A method for constructing a list of most probable modes, MPM, wherein the method comprises: determining whether the left block of the current coding block is available or not, whether the left block of the current coding block is available, adding the left block intra prediction mode to the MPM list; determining whether the top block of the current coding block is available or not, if the top block of the current coding block is available, adding the top block intra prediction mode to the MPM list; when defending the planar mode in the MPM list, adding the planar mode to the MPM list; if there is no DC mode in the MPM list, adding the DC mode to the MPM list.

Option 2 implementation. The method of Embodiment 1, wherein when the left block prediction mode is not intra prediction mode, the left block of the current coding block is unavailable.

Option 3 implementation. The method of embodiment 1 or 2, wherein when the current coding block is the coding block located at the leftmost part of the frame, the left block of the current coding block is unavailable.

Option 4 implementation. The method as in any one of embodiments 1-3, wherein parallel processing is supported and the current coding block is the coding block located at the very left of the tile, the left block of the current coding block is not available.

Option 5 implementation. The method as in any one of embodiments 1-4, wherein parallel processing is not supported and the current coding block is a coding block located at the leftmost side of the tile but not at the leftmost side of the frame, the left block of the current coding block is available.

Option 6 implementation. The method of any one of embodiments 1 to 5, wherein parallel processing is supported and the current coding block is the coding block located at the leftmost part of the segment, the left block of the current coding block is inaccessible.

Option 7 implementation. The method as in any one of embodiments 1-6, wherein parallel processing is not supported and the current coding block is a coding block located at the leftmost part of the segment but not at the leftmost part of the frame, the leftmost block of the current coding block is available.

Option 8 implementation. The method of any one of embodiments 1 to 7, wherein when the top block prediction mode is not an intra prediction mode, the top block of the current coding block is unavailable.

Option 9 implementation. The method as in any one of embodiments 1 to 8, wherein when the current coding block is the coding block located at the topmost part of the frame, the top block of the current coding block is unavailable.

Option 10 implementation. The method as in any one of embodiments 1-9, wherein parallel processing is supported and the current coding block is the coding block located at the topmost part of the tile, the top block of the current coding block is unavailable.

Option 11 implementation. The method according to any of embodiments 1-10, wherein parallel processing is not supported, the current coding block is the coding block located at the topmost part of the tile, but not at the topmost part of the frame, the top block of the current coding block is available.

Option 12 implementation. The method of any one of embodiments 1-11, wherein parallel processing is supported and the current coding block is the coding block located at the topmost part of the segment, the top block of the current coding block is not available.

Option 13 implementation. The method as in any one of embodiments 1-12, wherein parallel processing is not supported and the current coding block is a coding block located at the topmost part of the segment but not at the topmost part of the frame, the top block of the current coding block is available.

Option 14 implementation. The method of any of embodiments 1-13, when the size of the linear buffer is limited and the current coding unit is a coding unit located on the uppermost side of the current CTU, the upper block of the current coding unit is not available.

Option 15 implementation. The method according to any one of embodiments 1-14, the method further comprising:

if the left block of the current coding block is available and the intra prediction mode of the left block is angular, adding an offset to the left block prediction mode to obtain a new prediction mode, if the new prediction mode is not in the MPM list, adding the new prediction mode to the MPM list.

Option 16 implementation. The method of embodiment 15 wherein the offset is -1.

Option 17 implementation. The method of embodiment 15 wherein the offset is 1.

Option 18 implementation. The method according to any one of embodiments 1-17, the method further comprising:

if the top block of the current coding block is available and the intra prediction mode of the top block is corner mode, adding an offset to the top block prediction mode to obtain an upshift prediction mode, if the upshift prediction mode is not in the MPM list, adding an upshift prediction mode to mpm list.

Option 19 implementation. The method of embodiment 18 wherein the offset is -1.

Embodiment 20. The method of embodiment 18 wherein the offset is 1.

Embodiment 21. The method according to any one of embodiments 1-20, the method further comprising:

adding vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) to the MPM list.

Embodiment 22. The method according to any one of embodiments 1-20, the method further comprising a corner mode candidate list comprising or consisting of: vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2(2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) in the MPM list; and the method further comprises: iteratively determining, according to their order in the list, whether the list angular mode is in the MPM list, and if the corresponding angular mode is not in the MPM list, adding the corresponding angular mode to the MPM list.

Option 23 implementation. The method as in any one of embodiments 1-20, wherein building the MPM list starts from the step of determining whether the left block of the current coding block is available or not, for example, based on an empty MPM list.

Option 24 implementation. The method according to any one of embodiments 1-23, the method further comprising: if the left block of the current coding block is unavailable and another block in the general left direction is available (e.g., BL or AL in FIG. 5), inserting the intra prediction mode of the other block into the MPM list if the left block is available, do not insert another block's intra-prediction mode into the MPM list.

Option 25 implementation. The method according to any one of embodiments 1-23, the method further comprising: if the upper block of the current coding block is not available and another block in the general direction indicated above is available (e.g., AR or AL in FIG. 5), inserting the intra prediction mode of the other block in the MPM list if the top block is available, do not insert into another block's intra prediction mode MPM list.

Option 26 implementation. The method according to any one of embodiments 1-25, the method further comprising: adding to the MPM a list of vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 (2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX), if they are not in the MPM list.

Option 27 implementation. The method according to any one of embodiments 1-26, the method further comprising:

if both the left and the top block of the current coding block are not angular, then additionally check one more neighboring block (for example, BL, AL or AR in Fig. 5). If any of them (BL, or AL, or AR) is angular, then use that angular mode as the initial angular mode for the -1 + 1 derivation process, as described earlier.

Option 28 implementation. The encoder contains a processing circuit for performing the method according to any one of embodiments 1-27.

Option 29 implementation. The decoder includes a processing circuit for performing the method according to any one of embodiments 1-27.

Option 30 implementation. A computer program product containing program code for performing the method according to any one of embodiments 1-27.

Option 31 implementation. The most probable mode list decoder, MPM, contains:

one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, the programs, when executed by the processors, configuring the decoder to execute the method according to any one of embodiments 1-27.

Option 32 implementation. An encoder for building a list of the most likely mode, MPM, containing:

one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, the programs, when executed by the processors, configuring the encoder to execute the method according to any one of embodiments 1-27.

Option 33 implementation. A method for constructing a list of the most probable mode, MPM, for intra prediction, the method comprising: determining whether the left block of the current coding block is available or not, if the left block of the current coding block is available, adding the left block intra prediction mode list to the MPM; determining whether the top block of the current coding block is available or not, if the top block of the current coding block is available and the top block intra prediction mode is not in the MPM list, adding the top block intra prediction mode to the MPM list; if there is no planar mode in the MPM list, adding planar mode to the MPM list; if there is no DC mode in the MPM list, adding the DC mode to the MPM list.

Option 34 implementation. The method of embodiment 33, wherein when the current coding block is the coding block located at the leftmost part of the frame, the left block of the current coding block is unavailable.

Option 35 implementation. The method of embodiment 33 or 34, wherein when the current coding block is a coding block not located at the leftmost part of the frame, the left block of the current coding block is available.

Option 36 implementation. The method according to any one of embodiments 33-35, wherein when the current coding block is the coding block located at the topmost part of the frame, the top block of the current coding block is unavailable.

Option 37 implementation. The method as in any one of embodiments 33-36, wherein when the current coding block is a coding block not located at the very top of the frame, the top block of the current coding block is available.

Option 38 implementation. The method of any one of embodiments 33-37, wherein the method further comprises:

if the left block of the current coding block is available and the intra prediction mode of the left block is angular, adding an offset to the left block prediction mode to obtain a new prediction mode, if the new prediction mode is not in the MPM list, adding the new prediction mode to the MPM list.

Option 39 implementation. The method of any one of embodiments 33-38, wherein the method further comprises:

if the top block of the current coding block is available and the intra prediction mode of the top block is corner mode, adding an offset to the top block prediction mode to obtain an upshift prediction mode, if the upshift prediction mode is not in the MPM list, adding an upshift prediction mode to mpm list.

Option 40 implementation. The method of embodiment 38 or 39 wherein the offset is -1.

Option 41 implementation. The method of embodiment 38 or 39 wherein the offset is 1.

Option 42 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list, wherein the intra prediction mode set comprises vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2(2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX).

Option 43 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding an intra prediction mode to an intra prediction mode set containing vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2(2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) in accordance with the above order in the MPM list, when the intra prediction mode is not contained in the MPM list, as long as the number of prediction modes is equal to the threshold value.

Option 44 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the left block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value,

checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list in which the intra prediction mode set contains the vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX), or internal mode 2 (2).

Option 45 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the left block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding to the MPM intra prediction mode list an intra prediction mode set containing vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX ) or intra mode 2 (2) in accordance with the above order, when the intra prediction mode is not included in the MPM list until the number of prediction modes becomes equal to a threshold value.

Option 46 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list, wherein the intra prediction mode set comprises a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, or an intra prediction mode corresponding to VER_IDX with an offset of 4.

Option 47 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold, iteratively adding to the MPM intra prediction mode list an intra prediction mode set containing a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, or an intra prediction mode corresponding to VER_IDX with an offset of 4 according to the above order, when the intra prediction mode is not included in the MPM list, until the number of prediction modes becomes equal to a threshold.

Option 48 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list, wherein the intra prediction mode set comprises a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 4, or an intra prediction mode corresponding to VER_IDX with an offset of -4.

Option 49 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding to the MPM intra prediction mode list an intra prediction mode set containing a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 4, or an intra prediction mode intra prediction corresponding to VER_IDX with an offset of -4, in accordance with the above order, when the intra prediction mode is not included in the MPM list, as long as the number of mode predictions equals the threshold value.

Option 50 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the left block of the current coding block is not available and the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode not contained in the MPM list, in which the intra prediction mode set contains one of the following intra prediction mode sets: vertical mode (VER_IDX), vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode, corresponding VER_IDX with offset 1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of 4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of +1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of 1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -1.

Option 51 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the left block of the current coding block is not available and the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding to the MPM list of the intra prediction mode of the set of intra prediction modes in accordance with the above order, when the intra prediction mode is not contained in the MPM list, until until the number of prediction modes becomes equal to the threshold value;

wherein the intra prediction mode set contains one of the following intra prediction mode sets:

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of 1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of 4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -4, and an intra prediction mode corresponding to VER_IDX with an offset of +1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VDIA_IDX with an offset of -1, and an intra prediction mode corresponding to VER_IDX with an offset of 1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -4; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -1; or

a vertical mode (VER_IDX), a vertical diagonal mode (VDIA_IDX), an intra prediction mode corresponding to VER_IDX with an offset of 1, and an intra prediction mode corresponding to VDIA_IDX with an offset of -1.

Option 52 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the upper block of the current coding block is unavailable, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list, if the first intra prediction mode is not included in the MPM list, in which the intra prediction mode set contains horizontal mode (HOR_IDX), intra mode 2 (2), diagonal mode (DIA_IDX), or vertical diagonal mode (VDIA_IDX).

Option 53 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the upper block of the current coding block is unavailable, iteratively adding an intra prediction mode to a set of intra prediction modes containing horizontal mode (HOR_IDX ), intra mode 2(2), diagonal mode (DIA_IDX), or vertical diagonal mode (VDIA_IDX) in accordance with the above order, in the MPM list, when the intra prediction mode is not contained in the MPM list, as long as the number of prediction modes is equal to the threshold value.

Option 54 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not contained in the MPM list, in which the intra prediction mode set contains vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2(2), vertical diagonal mode (VDIA_IDX), or diagonal mode (DIA_IDX) ).

Option 55 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available, iteratively adding to the MPM the intra prediction mode list of the intra prediction mode set containing vertical mode (VER_IDX), horizontal mode (HOR_IDX ), intra mode 2 (2), vertical diagonal mode (VDIA_IDX) or diagonal mode (DIA_IDX) in accordance with the above order, when the intra prediction mode is not included in the MPM list until the number of prediction modes becomes equal to the threshold value.

Option 56 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the upper block of the current coding block is unavailable, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list, if the first intra prediction mode is not included in the MPM list, in which the intra prediction mode set contains horizontal mode (HOR_IDX), intra mode 2 (2), diagonal mode (DIA_IDX), or vertical diagonal mode (VDIA_IDX).

Option 57 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the top block of the current coding block is not available, iteratively adding to the MPM intra prediction mode list of the intra prediction mode set containing horizontal mode (HOR_IDX), intra mode 2 (2), diagonal mode (DIA_IDX ) or vertical diagonal mode (VDIA_IDX) according to the above order, when the intra prediction mode is not included in the MPM list, as long as the number of prediction modes is equal to the threshold value.

Option 58 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM a list if the first intra prediction mode is not contained in the MPM list, in which the intra prediction mode set contains a vertical mode (VER_IDX), a horizontal mode (HOR_IDX), an intra prediction mode corresponding to VER_IDX with an offset of -4, or an intra prediction mode corresponding to VER_IDX with offset 4.

Option 59 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the number of intra prediction modes in the MPM list is less than a threshold value, the left block of the current coding block is available and the top block of the current coding block is available, iteratively adding to the MPM list an intra prediction mode of an intra prediction mode set containing vertical mode (VER_IDX), horizontal mode (HOR_IDX ), an intra prediction mode corresponding to VER_IDX with an offset of -4, or an intra prediction mode corresponding to a VER_IDX with an offset of 4, in accordance with the above order, when the intra prediction mode is not included in the MPM list until the number of prediction modes becomes equal to a threshold.

Option 60 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the top block of the current coding block is unavailable and the number of intra prediction modes in the MPM list is less than a threshold value, checking whether the first intra prediction mode of the intra prediction mode set is contained in the MPM list, and adding the first intra prediction mode to the MPM list if the first intra prediction mode is not is contained in the MPM list, in which the intra prediction mode set contains one of the following intra prediction mode sets:

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to HOR_IDX with an offset of 1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to HOR_IDX with offset -4, and HOR_IDX add offset 4; or

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 4, and an intra prediction mode corresponding to HOR_IDX with an offset of -1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to intra mode 2 (2) with offset 4, and intra prediction mode corresponding to HOR_IDX with offset 1; or

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 1, and an intra prediction mode corresponding to HOR_IDX with an offset of -1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to intra mode 2 (2) with offset 1, and intra prediction mode corresponding to HOR_IDX with offset 1; or

a horizontal mode (HOR_IDX), intra mode 2(2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to intra mode 2(2) with an offset of 4; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to HOR_IDX with offset 1, and intra prediction mode corresponding to intra mode 2 (2) with offset 4; or

a horizontal mode (HOR_IDX), intra mode 2(2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to intra mode 2(2) with an offset of 1; or

horizontal mode (HOR_IDX), intra mode 2(2), intra prediction mode corresponding to HOR_IDX with offset 1, and intra prediction mode corresponding to intra mode 2(2) with offset 1.

Option 61 implementation. The method of any one of embodiments 33-41, wherein the method further comprises:

if the top block of the current coding block is not available and the number of intra prediction modes in the MPM list is less than a threshold value, iteratively adding to the MPM list of the intra prediction mode of the set of intra prediction modes in accordance with the above order, when the intra prediction mode is not contained in the MPM list, until until the number of prediction modes becomes equal to the threshold value;

wherein the intra prediction mode set contains one of the following intra prediction mode sets:

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to HOR_IDX with an offset of 1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to HOR_IDX with offset -4, and HOR_IDX add offset 4; or

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 4, and an intra prediction mode corresponding to HOR_IDX with an offset of -1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to intra mode 2 (2) with offset 4, and intra prediction mode corresponding to HOR_IDX with offset 1; or

horizontal mode (HOR_IDX), intra mode 2 (2), an intra prediction mode corresponding to intra mode 2 (2) with an offset of 1, and an intra prediction mode corresponding to HOR_IDX with an offset of -1; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to intra mode 2 (2) with offset 1, and intra prediction mode corresponding to HOR_IDX with offset 1; or

a horizontal mode (HOR_IDX), intra mode 2(2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to intra mode 2(2) with an offset of 4; or

horizontal mode (HOR_IDX), intra mode 2 (2), intra prediction mode corresponding to HOR_IDX with offset 1, and intra prediction mode corresponding to intra mode 2 (2) with offset 4; or

a horizontal mode (HOR_IDX), intra mode 2(2), an intra prediction mode corresponding to HOR_IDX with an offset of -1, and an intra prediction mode corresponding to intra mode 2(2) with an offset of 1; or

horizontal mode (HOR_IDX), intra mode 2(2), intra prediction mode corresponding to HOR_IDX with offset 1, and intra prediction mode corresponding to intra mode 2(2) with offset 1.

Option 62 implementation. An encoder containing a processing circuit for performing a method according to any one of embodiments 33-61.

Option 63 implementation. A decoder containing a processing circuit for performing a method according to any one of embodiments 33-61.

Option 64 implementation. A computer program product containing program code for performing a method according to any one of embodiments 33-61.

Option 65 implementation. The most probable mode list decoder, MPM, contains:

one or more processors; and

a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, in which the programs, when executed by the processors, configures the decoder to execute the method according to any one of embodiments 33-61.

Option 66 implementation. An encoder for listing the most likely mode, MPM, containing:

one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, the programs, when executed by the processors, configuring the encoder to execute the method according to any one of embodiments 33-61.

10 is a diagram of a network device 1300 according to an embodiment of the present invention. The network device 1300 is suitable for implementing the disclosed embodiments as described herein. The network device 1300 includes input ports 1310 and receive units (Rx) 1320 for receiving data; a processor, logical unit, or central processing unit (CPU) 1330 for processing data; blocks 1340 transmitter (Tx) and output ports 1350 for data transmission; and a memory 1360 for storing data. The network device 1300 may also include optical-electrical (OE) components and electrical-optical (EO) components connected to input ports 1310, receive units 1320, transmitter units 1340, and output ports 1350 for input or output of optical or electrical signals.

The processor 1330 is implemented in hardware and software. Processor 1330 may be implemented as one or more CPU chips, cores (eg, as a multi-core processor), field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), and digital signal processors (DSPs). The processor 1330 is connected to input ports 1310, receiver units 1320, transmitter units 1340, output ports 1350, and memory 1360. Processor 1330 includes an encoder 1370. Encoding module 1370 implements the disclosed embodiments described above. For example, encoding module 1370 implements, processes, prepares, or provides various network functions. Thus, the use of the encoder 1370 provides a significant improvement in the functionality of the network device 1300 and allows the network device 1300 to be converted to another state. Alternatively, encoding module 1370 is implemented as instructions stored in memory 1360 and executed by processor 1330.

Memory 1360 includes one or more disks, tape drives, and solid state drives and can be used as a storage device for overflowing data, for storing programs when such programs are selected for execution, and for storing instructions and data that are read during program execution. Memory 1360 may be volatile and/or non-volatile and may be read only memory (ROM), random access memory (RAM), ternary content addressable memory (TCAM), and/or static random access memory (SRAM).

10 is a block diagram of a device 1100 that can be used to implement various embodiments. Device 1100 may be source device 102 as shown in FIG. 1 or video encoder 200 as shown in FIG. 2 or destination device 104 as shown in FIG. 1 or video decoder 300 as shown in FIG. Additionally, device 1100 may include one or more of the elements described. In some embodiments, device 1100 is equipped with one or more input/output devices such as a speaker, microphone, mouse, touch screen, keyboard, printer, display, and the like. Device 1100 may include one or more central processing units (CPUs) 1510, memory 1520, mass storage device 1530, video adapter 1540, and I/O interface 1560 connected to the bus. A bus is one or more of several bus architectures of any type, including a memory bus or memory controller, a peripheral bus, a video bus, and the like.

The CPU 1510 may be of any type of electronic data processor. The memory 1520 may have or be any type of system memory such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read only memory (ROM), a combination thereof, or the like. In an embodiment, memory 1520 may include ROM for use during bootup and DRAM for storing programs and data for use during program execution. In embodiments, memory 1520 is non-volatile. Mass storage device 1530 includes any type of storage device that stores data, programs, and other information, and for providing access to data, programs, and other information via a bus. The mass storage device 1530 includes, for example, one or more of a solid state drive, a hard disk drive, a magnetic disk drive, an optical disk drive, and the like.

Video adapter 1540 and I/O interface 1560 provide interfaces for connecting external I/O devices to device 1100. For example, device 1100 may provide a command interface to SQL clients. As illustrated, examples of I/O devices include a display 1590 connected to a video adapter 1540 and any mouse/keyboard/printer combination 1570 connected to an I/O interface 1560. Other devices may be connected to device 1100, and additional or fewer interface cards may be used. For example, a serial interface card (not shown) may be used to provide a serial interface for a printer.

Device 1100 also includes one or more network interfaces 1550, which include wired links, such as an Ethernet cable or the like, and/or wireless links to access points or one or more networks 1580. Network interface 1550 provides the ability to device 1100 to communicate with remote devices via networks 1580. For example, network interface 1550 may provide communication with a database. In an embodiment, the device 1100 is connected to a local area network or a wide area network for processing data and communicating with remote devices such as other processing units, the Internet, remote repositories, and the like.

To calculate the values of the weight coefficients, a piecewise linear approximation is used, which is necessary to predict the pixels in a given block. The piecewise linear approximation, on the one hand, significantly reduces the computational complexity of the distance-weighted prediction mechanism compared to the direct calculation of the weights, and on the other hand, helps to achieve higher accuracy of the weight values compared to prior art simplifications.

Embodiments can be applied to other bidirectional and position-dependent intra prediction methods (e.g., various modifications of PDPC), as well as mechanisms that use weights that depend on the distance from one pixel to another to blend different parts of an image (e.g., some ways of blending in image processing).

Implementations of the subject matter and operations described in this disclosure may be implemented in digital electronic circuits, or in computer software, firmware, or hardware, incorporating the structures disclosed in this disclosure and their structural equivalents, or in a combination of one or more of them. Implementations of the subject matter described in this disclosure may be implemented as one or more computer programs, that is, one or more computer program instruction modules encoded on a computer storage medium to execute or control the operation of a data processing device. Alternatively or in addition, the program instructions may be encoded on an artificially generated propagation signal, such as a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to a suitable receiver device for data processing. A computer storage medium, such as a computer readable medium, can be or reside in a computer readable storage device, a computer readable storage chip, a random access or sequential access memory array or device, or a combination of one or more of these. Moreover, although the computer storage medium is not a distributed signal, the computer storage medium may be the source or destination of computer program instructions encoded in an artificially generated distributed signal. A computer storage medium may also be or be contained in one or more separate physical and/or non-volatile components or media (eg, multiple CDs, disks, or other storage devices).

In some implementations, the operations described in this disclosure may be implemented as a hosted service provided on a server in a cloud computing network. For example, computer-readable storage media may be logically grouped and available on a cloud computing network. The servers in the cloud computing network may include a cloud computing platform for providing cloud services. The terms "cloud", "cloud computing" and "cloudy" can be used interchangeably, if necessary, without departing from the scope of the present invention. Cloud services may be hosted services that are provided by servers and delivered over a network to a client platform to enhance, supplement, or replace applications running locally on the client computer. The schema can use cloud services to quickly receive updates to software, applications, and other resources that would otherwise take a long period of time before the resources can be delivered to the schema.

A computer program (also known as a program, software, software application, script, or code) may be written in any form of a programming language, including compiled or interpreted languages, declarative or procedural languages, and it may be deployed in any form, including into itself as a standalone program or as a module, component, subroutine, object, or other device suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored in a portion of a file that contains other programs or data (for example, one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coherent files (for example, files that store one or more modules, subroutines, or pieces of code). The computer program may be deployed to run on a single computer or on multiple computers that are located at a single site or distributed across multiple sites and interconnected by a communications network.

The processes and logical flows described in this disclosure may be executed by one or more programmable processors executing one or more computer programs to perform actions on input data and generate output data. Processes and logical threads can also run, and the device can also be implemented as a special-purpose logic circuit, such as an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

Processors suitable for executing a computer program include, for example, both general purpose and special purpose microprocessors, as well as any one or more processors of any type of digital computer. Typically, the processor will receive instructions and data from read-only memory or random access memory, or both. The main elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. Typically, the computer will also include or be operably connected to receive data from or transmit data to one or both mass storage devices for data storage, such as magnetic, magneto-optical disks or optical disks. However, your computer may not have such devices. In addition, the computer may be embedded in another device, such as a mobile phone, personal digital assistant (PDA), mobile audio or video player, game console, global positioning system (GPS) receiver, or portable storage device (such as a flash drive with Universal Serial Bus (USB)), just to name a few. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard drives or removable drives; magneto-optical disks; and CD-ROM and DVD-ROM discs. The processor and memory can be supplemented with or incorporated into custom logic.

While the present invention contains many specific implementation details, they should not be construed as limiting the scope of any implementations or what may be claimed, but rather as a description of features specific to particular implementations of particular implementations. Some of the features described in this disclosure in the context of individual implementations may also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable subcombination. Moreover, although the features may be described above as operating in certain combinations and even originally claimed as such, one or more features of the claimed combination may in some cases be excluded from the combination and the claimed combination may be directed to a subcombination or variation of the subcombination.

Likewise, although the operations are shown in the drawings in a particular order, this should not be understood as a requirement that such operations be performed in the particular order shown or in sequential order, or that all the illustrated operations be performed to achieve the desired result. In certain circumstances, multitasking and parallel processing can be useful. Moreover, the separation of the various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the software components and systems described can generally be integrated together into a single software product or packaged into multiple software products.

Thus, specific implementations of the subject invention have been described. Other implementations are included in the scope of the following claims. In some cases, the steps set forth in the claims may be performed in a different order and still lead to the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing may be useful.

While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the present invention. The present examples are to be considered illustrative and not restrictive, and the intention is not to be limited by the details given here. For example, various elements or components may be combined or integrated into another system, or certain features may be omitted or not implemented.

Additionally, the methods, systems, subsystems, and methods described and illustrated in various embodiments as discrete or separate may be combined or integrated with other systems, modules, technologies, or methods without departing from the scope of the present invention. Other elements shown or discussed as related or directly related to or interacting with each other may be indirectly connected or interact through some interface, device, or intermediate component, electrically, mechanically, or otherwise. A person skilled in the art can implement other examples of changes, replacements and changes that can be made without deviating from the spirit and scope disclosed in this document.

Claims (38)

1. A decoding method for decoding the current video block, comprising the steps of: getting a most likely modes (MPM) flag value for the current block from the bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and MPM set for the current block; wherein when the intra prediction mode of the left neighbor block of the current block is the planar mode and the intra prediction mode of the top neighbor block of the current block is the planar mode, The MPM prediction mode set includes: planar mode, DC mode, vertical mode, horizontal mode, an intra prediction mode corresponding to the first offset vertical mode, and an intra prediction mode corresponding to the second offset vertical mode, the first offset being -4. 2. The method of claim 1, wherein when the MPM value of the flag for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode. 3. The method according to claim 1 or 2, wherein the second offset is +4. 4. A decoding method for decoding the current video block, comprising the steps of: getting a most likely modes (MPM) flag value for the current block from the bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and MPM set for the current block; wherein when the intra prediction mode of the left neighbor block of the current block is the planar mode and the intra prediction mode of the upper neighbor block of the current block is the DC mode, the MPM prediction mode set contains: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode corresponding to the vertical mode with a first offset, and an intra prediction mode corresponding to a vertical mode with a second offset, the first offset being −4. 5. The method of claim 4, wherein when the MPM value of the flag for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode. 6. The method according to claim 4 or 5, wherein the second offset is +4. 7. Decoding method for decoding the current video block, comprising the steps of: getting a most likely modes (MPM) flag value for the current block from the bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and MPM set for the current block; wherein when the left neighbor block of the current block is not available and the intra prediction mode of the upper neighbor block of the current block is planar mode, the MPM prediction mode set contains: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode corresponding to the first offset vertical mode, and an intra prediction mode corresponding to the second offset vertical mode, the first offset being -4. 8. The method of claim 7, wherein when the MPM flag value for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode. 9. The method according to claim 7 or 8, wherein the second offset is +4. 10. A decoding method for decoding the current video block, comprising the steps of: getting a most likely modes (MPM) flag value for the current block from the bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and MPM set for the current block; wherein when the left neighbor block of the current block is unavailable and the top neighbor block of the current block is unavailable, the MPM prediction mode set contains: planar mode, DC mode, vertical mode, horizontal mode, an intra prediction mode corresponding to the first offset vertical mode, and an intra prediction mode corresponding to vertical mode with a second offset, with the first offset equal to -4. 11. The method of claim 10, wherein when the MPM value of the flag for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode. 12. The method according to any one of claims 10, 11, wherein the second offset is +4. 13. A decoding method for decoding the current video block, comprising the steps of: getting a most likely modes (MPM) flag value for the current block from the bitstream; obtaining an MPM index for the current block from the bitstream when the value of the MPM flag indicates that the intra prediction mode for the current block is an intra prediction mode contained in the MPM intra prediction mode set; obtaining an intra prediction mode value for the current block based on the MPM index and MPM set for the current block; wherein when the intra prediction mode of the left neighbor block of the current block is the planar mode and the upper neighbor block of the current block is unavailable, the MPM prediction mode set comprises: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode corresponding to the first offset vertical mode, and an intra prediction mode corresponding to the second offset vertical mode, the first offset being -4. 14. The method of claim 13, wherein when the MPM flag value for the current block is 1 and the MPM index for the current block is 0, the intra prediction mode for the current block is a planar mode. 15. The method according to claim 13 or 14, wherein the second offset is +4. 16. A decoder comprising a processing circuit configured to implement the method of any one of claims 1-15. 17. A computer-readable storage medium storing instructions causing, when executed by one or more processors, the execution of a method according to any one of claims 1-15.

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