RU2780222C2 - Method and device for internal prediction - Google Patents

Abstract

FIELD: image encoding/decoding.

SUBSTANCE: invention relates to the field of image encoding and decoding, in particular to a method for internal prediction. A method for compiling a list of the most probable modes (hereinafter – MPM) for the prediction process corresponding to a video block is proposed. The method includes: determination of whether the left block of the current encoding block is available or not, if the left block of the current encoding block is available, addition of an internal prediction mode of the left block to MPM list; determination of whether the upper block of the current encoding block is available or not, if the upper block of the current encoding block is available, addition of an internal prediction mode of the upper block to MPM list; addition of an offset to the prediction mode of the left block to obtain a new prediction mode, if the left block of the current encoding block is available, and the internal prediction mode of the left block is an angular mode; and addition of the new prediction mode to MPM list, if the new prediction mode is not in MPM list; or addition of an offset to the prediction mode of the upper block to obtain the prediction mode of the upper block with an offset, if the upper block of the current encoding block is available, and the internal prediction mode of the upper block is an angular mode; and addition of the prediction mode of the upper block with an offset to MPM list, if the prediction mode of the upper block with an offset is not in MPM list. MPM list is used to obtain an index value corresponding to the prediction mode of the image block to increase encoding efficiency.

EFFECT: increase in the efficiency of encoding/decoding based on compiling MPM list.

14 cl, 1 tbl, 10 dwg

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 device to decode and view the video. Video quality has improved over the years, for example with higher resolutions, color depth and frame rates. This has led to an increase in data flows, which are now usually transmitted over the Internet and mobile networks.

However, higher resolution videos usually require more bandwidth because they contain more information. 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. Thus, video coding standards try to strike a balance between bandwidth requirements and quality.

High Efficiency Video Coding (HEVC) is an example of a video coding standard that is commonly 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 latest collaborative video project created by the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Standards Organizations by the Moving Picture Experts Group (MPEG), who work together in a well-known partnership, as the Joint Video Research Team (JVET). VVC is also referred to as ITU-T H.266/Next Generation Video Coding (NGVC). VVC removes the concept of multiple partition types, i.e. removes the concepts of CU, PU, and TU partitioning, except when needed for CUs that are too large for the maximum transform length, and maintains 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 reconstructed block samples. 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 exploring the potential need to standardize a future compressible video coding technology that far exceeds the capabilities of the current HEVC standard (including 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 effort known as the Joint Video Research Team (JVET) to evaluate compression technology projects proposed by their experts in the field.

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

The intra coding mode scheme currently described in the BMS is considered complex, and the disadvantage of the non-selected mode set is that the index list is always constant and not adaptive based on the properties of the current block (eg, for INTRA neighbor block modes).

The essence of the invention

The present measurement provides an apparatus and method for intra prediction. The device and method uses an improved process to compile a list of the most likely modes. The scope of protection is determined by the claims. Additional forms of implementation are obvious from the dependent claims, description and drawings.

According to an aspect, the present invention relates to a method for listing a most likely mode, MPM, for a prediction process, the method comprising: determining whether the left block of the current block is available or not, if the left block of the current 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; adding an offset to the left block intra prediction mode to obtain a new prediction mode if the left block of the current coding block is available and the left block intra prediction mode is an angular mode; and adding a new prediction mode to the MPM list if the new prediction mode is not in the MPM list; and/or adding an offset to the top block intra prediction mode to obtain the offset-top prediction mode if the top block of the current coding block is available and the top block intra prediction mode is an angle mode; and adding a bias-top prediction mode to the MPM list if the bias-top prediction mode is not in the MPM list.

In one option, the offset is -1 or +1:

In an embodiment, the method further comprises: if there is no planar mode in the MPM list, adding the planar mode to the MPM list; and, if the DC mode is not in the MPM list, adding the DC mode to the MPM list.

In an embodiment, when the left block prediction mode is not an intra prediction mode, the left block of the current coding block is not available.

In an embodiment, when the current coding block is the coding block located on the leftmost side of the frame, the left block of the current coding block is not available.

In an embodiment, when parallel processing is supported and the current coding block is a coding block located on the leftmost side of a segment or tile, the left block of the current coding block is not available.

In an embodiment, when parallel processing is not supported and the current coding block is a coding block located on the leftmost side of a segment or tile, but not on the leftmost side of a frame, the left block of the current coding block is available.

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

In an embodiment, when the current coding block is the coding block located on the uppermost side of the frame, the top block of the current coding block is not available.

In an embodiment, when parallel processing is supported and the current coding block is the coding block located on the topmost side of the segment or tile, the top block of the current coding block is not available.

In an embodiment, when parallel processing is not supported and the current coding block is a coding block located on the topmost side of a segment or tile, but not on the topmost side of a frame, the topmost block of the current coding block is available.

In an embodiment, when the size of the linear buffer is limited and the current coding unit is a coding unit located on the topmost side of the current coding tree block, CTU, the top block of the current coding unit is not available.

According to an aspect, the present invention relates to an encoder containing a processing circuit for performing any of the above methods.

According to an aspect, the present invention relates to a decoder comprising a processing circuit for performing any of the above methods.

According to an aspect, the present invention relates to a software product containing software code for performing any of the above methods.

Brief description of the drawings

The following embodiments are described in more detail with reference to the accompanying drawings, in which:

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

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

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

fig. 4 shows a diagram illustrating 67 intra prediction modes;

fig. 5 shows a diagram illustrating neighboring blocks for obtaining MPM;

fig. 6 shows a diagram illustrating an example of the first three modes in the process of generating a list of the remaining modes;

fig. 7 shows a diagram illustrating second layer adjacent block intra prediction modes used to obtain the first three modes in the remaining mode list;

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

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

fig. 10 shows a block diagram of the device.

The following identical reference numbers refer to identical or at least functionally equivalent functions, unless expressly stated otherwise.

Detailed description of embodiments

In the following description, reference is made to the accompanying drawings, which form part of the present invention and which show specific aspects of the present invention by way of illustration. It is clear that embodiments of the invention can be used in other aspects and contain structural or logical changes not shown in the drawings. Therefore, the following detailed description should not be considered in a limiting sense, and the scope of the present invention is determined by the appended claims.

For example, it is obvious that the invention in connection with the described method can also be used for a corresponding device or system configured 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. On the other hand, for example, if a particular device is described in terms of one or more blocks, such as functional blocks, the corresponding method may include one step to perform the functionality of one or more blocks (for example, one step to perform the functionality of one or more blocks). blocks, or a plurality of steps, each of which performs the functionality of one or more of the plurality of blocks), even if such one or more steps 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" can be used interchangeably in the field of video coding as well as in the present invention.

Video encoding (or encoding in general) contains two parts: video encoding and video decoding. Video encoding is performed at the source side, typically involving processing (eg, by compressing) the source video images to reduce the amount of data needed to represent the video images (for more efficient storage and/or transmission). Video decoding is performed on the destination side and usually contains inverse processing compared to the encoder for recovering video images. Embodiments relating to "coding" video images (or images in general) should be understood as referring to "coding" or "decoding" video images or corresponding video sequences. The combination of an encoding part and a decoding part is also called CODEC (Coding and Decoding).

In the case of lossless video coding, the original video images can be reconstructed, i.e. the restored video images have the same quality as the original video images (assuming no transmission loss or other data loss during storage or transmission). In the case of lossy video coding, in order to reduce the amount of data representing video images, additional compression is performed, for example by quantization, which cannot be fully recovered in the decoder, i.e. the quality of the restored video images is lower or worse than the quality of the original video images.

Each image is usually divided into a set of non-overlapping blocks. Image encoding/decoding is typically performed at the block level, where, for example, inter-prediction or intra-prediction is used to generate a prediction block to subtract the prediction block from the current block (the block currently being processed/to be processed) to obtain a residual block , which is further converted and quantized to reduce the amount of data that must be transmitted (compressed), while at the decoder side, inverse processing is applied to the encoded/compressed block to recover the block for presentation.

Fig. 1 is a conceptual or schematic block diagram illustrating an example of an encoding system, such as a video encoding system, 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 a video coding system represent examples of devices that can be configured to perform methods in accordance with the various examples described in the present invention. As shown in FIG. 1, the encoding system comprises 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 additionally, 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 contain or be any type of image capture device, for example, to capture a real image and/or any kind of image or commentary (for screen content encoding, some texts on the screen are also considered to be part of the image or frame to be encoded), a generating device, such as 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 (e.g., screen content, a virtual reality (VR) image), and/or any combination thereof (e.g. , 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 pel. 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 luma (short for luma) represents the brightness or intensity of the gray level (eg, as in a grayscale image), while the two chrominance components (abbreviated as Cb and Cr) represent components of chrominance or color information. Accordingly, a YCbCr image contains a luma sample array of luma sample values (Y) and two chrominance sample arrays of chroma values (Cb and Cr). RGB images can be converted or converted to YCbCr format and vice versa, this process is also known as color conversion or conversion. If the image is monochrome, it can only contain a luminance sample array.

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 Images. 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 can be anything, such as a wired or wireless interface, an optical interface according to any proprietary or standardized interface protocol. The interface for obtaining image data 17 may be the same interface as the communication interface 22 or 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 original 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 to transmit it to another device, for example, to 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 the destination device 14 is configured to receive the encoded image data 21 or the encoded data 13, for example, directly from the source device 12 or from any other source, such as a storage device, such as an encoded image data storage device.

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 and 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 line 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 communication interface 22 and communication interface 28 can be configured as unidirectional communication interfaces, as indicated by the arrow for encoded image data 13 in FIG. 1 pointing from source device 12 to receiving device 14, or as bi-directional communication interfaces, and may be configured to, for example, send and receive messages, such as establishing a connection, acknowledgment, and exchanging any other information related to the communication line and/or or data transmission, such as 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, based on FIG. 3).

The post-processor 32 of the source 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. The post-processing performed by the post-processing unit 32, 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 the display device 34.

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 contain both functionality, source device 12 or corresponding functionality of destination device 14. 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 of them. combinations.

As will be apparent to those skilled in the art based on the description, the presence and (precise) separation of functionality of various modules or functions in source device 12 and/or destination device 14, as shown in FIG. 1 may vary depending on the actual device and application.

Encoder 20 (eg, video encoder 20) and decoder 30 (eg, video decoder 30) may 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), programmable gate matrices (FPGA), 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 instructions in hardware using one or more processors to perform the methods of the present 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.

Source device 12 and destination device 14 may include any of a wide range of devices, including any kind of portable or stationary devices, such as laptops or laptops, mobile phones, smartphones, tablets or tablet computers, cameras, desktop computers, set-top boxes, televisions, display devices, digital media players, game consoles, video streaming devices (such as content service servers or content delivery servers), broadcast receiver, broadcast transmitter, etc., and may or may not use any type of operating system . In some cases, source device 12 and destination device 14 may be equipped for wireless communication. Thus, source device 12 and destination device 14 may be wireless communication devices.

In some cases, the video coding system illustrated in FIG. 1 is merely an example, and the methods of the present invention can be applied to video coding settings (eg, video coding or video decoding) that do not necessarily involve communication between encoding and decoding devices. In other examples, data is retrieved from local memory, streamed over a network, and the like. The video encoding device may encode and store data in memory, and/or the video decoder may retrieve and decode data from memory. In some examples, encoding and decoding is performed by devices that do not communicate with each other, but simply encode data into memory and/or retrieve and decode data from memory.

In FIG. 2 is a schematic/conceptual block diagram of an exemplary video encoder 20 that is capable of implementing the methods of the present invention. In the example in FIG. 2, video encoder 20 includes a residual calculation block 204, a transform processing block 206, a quantization block 208, an inverse quantization block and an inverse transform processing block 212, a reconstruction block 214, a buffer 216, a loop filtering block 220, a decoded picture buffer (DPB) 230, a 260 processing prediction and block 270 entropy encoding. 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 processor 260 form an encoder return path, in which the encoder return path corresponds to the decoder path (see decoder 30 in FIG. 3).

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

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, i.e., provide prediction block 265, which may be inter prediction block 245 or intra prediction block 255.

Mode selector 262 may be configured to select a prediction mode (e.g., intra or inter prediction mode) and/or a corresponding predictor 245 or 255 to be used as predictor 265 to calculate residual block 205 and to recover 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 minimal 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 intra prediction mode for the block, the intra prediction block 254 is also configured to provide an intra prediction parameter, that is, information indicating the selected intra prediction mode for the block, 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.

Embodiments of video encoder 20 may include an image splitter (not shown in FIG. 2) configured to divide an image into multiple (typically non-overlapping) image blocks. These blocks may also be referred to as root blocks, macroblocks (H.264/AVC), or coding tree blocks (CTBs) or coding tree blocks (CTUs) (H.265/HEVC and VVC). The image dividing block may be configured to use the same block size for all images of the video sequence and the corresponding grid defining the block size, or to change the block size between images, or subsets, or groups of images, and divide each image into corresponding blocks.

Like an image, an image block is again, or can be thought of as, a two-dimensional array or matrix of samples with intensity values (sample values), albeit smaller than the image. In other words, a block may contain, for example, one array of samples (for example, a luminance array in the case of a monochrome image, or an array of luminance or chrominance in the case of a color image) or three arrays of samples (for example, luminance and two chrominance arrays in the case of a color image) or any other number and/or kind of arrays, depending on the color format used. The number of samples in the horizontal and vertical direction (or axis) of the block determines the size of the block. Accordingly, the block may, for example, be an MxN array of samples (M-column per N-rows) or an MxN array of transform coefficients.

The video encoder embodiments shown in FIG. 2 may be configured to encode an image block by block, eg encoding and prediction is performed for each block.

The video encoder embodiments shown in FIG. 2 may be further configured to split and/or encode an image using segments (also referred to as video segments), in which an image may be split or encoded using one or more segments (typically without overlap), and each segment may contain one or multiple units (eg CTUs).

The video encoder embodiments shown in FIG. 2 may be further configured to partition and/or encode an image using tile groups (also referred to as tile groups) and/or tiles (also referred to as tiles), in which an image may be partitioned or encoded using one or more tile groups ( usually non-overlapping) and each tile group may contain, for example, one or more blocks (eg, CTUs) or one or more tiles, in which each tile, for example, may be rectangular in shape and may contain one or more blocks (eg, CTUs), such as full or fractional blocks.

Fig. 3 shows an exemplary video decoder 30 that is configured to perform the methods of the present invention. Video decoder 30, configured to receive encoded image data 21 (e.g., encoded bitstream), e.g., encoded by encoder 100, to obtain decoded image 131. encoded video segment images and associated syntax elements, from video encoder 100.

In the example in FIG. 3, the decoder 30 includes an entropy decoder 304, an inverse quantizer 310, an inverse transform processor 312, a reconstruction processor 314 (e.g., an adder 314), a buffer 316, a loop filter 320, a decoded image buffer 330, and a prediction processor 360. 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 step, generally the reverse of the encoding step described with respect to video encoder 20 in FIG. 2.

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), such as (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 a video segment level and/or a video block level.

The inverse quantizer 310 may be identical in function to the inverse quantizer 110, the inverse transform processing unit 312 may be identical in function to the inverse transform processing unit 112, the reconstruction block 314 may be identical to the reconstruction block 114, the buffer 316 may be identical in function to the buffer 116, loop filter 320 may be identical in function to loop filter 120, and decoded image buffer 330 may be identical in function to 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 be similar in function to inter prediction block 144, and intra prediction block 354 may functionally correspond to intra 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-associated parameters and/or information about the selected prediction mode, for example, from block 304 entropy decoding.

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

The prediction processing unit 360 is configured to determine prediction information for the video block of the current video segment by analyzing motion vectors and other syntax elements, and uses the prediction information to generate 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 the video blocks of a video segment, the inter prediction segment type (eg, B-segment, P-segment, or GPB- segment), structure information of one or more reference picture lists for the segment, motion vectors for each inter-prediction coded video block segment, inter prediction status for each inter-prediction 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 generate residual blocks in the pixel region.

Reconstructor 314 (eg, 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 reconstructed residual block 313 and values of the samples block 365 prediction.

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 unit 320 is shown in FIG. 3 as a loop filter, in other configurations, the loop filter unit 320 may be implemented as a post loop filter.

The decoded video blocks 321 in a given 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, no transform decoder 30 may perform inverse quantization of the residual signal directly without inverse transform processing unit 312 for certain 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.

The video decoder embodiments shown in FIG. 3 may be configured to split and/or decode an image using segments (also referred to as video segments), in which the image may be divided into or decoded using one or more segments (typically without overlap), and each segment may contain one or multiple units (eg CTUs).

The video decoder embodiments shown in FIG. 3 may be configured to partition and/or decode an image using tile groups (also referred to as tile groups) and/or tiles (also referred to as tiles), in which the image may be partitioned into or decoded using one or more tile groups ( usually non-overlapping), and each group of tiles may contain, for example, one or more blocks (for example, CTUs) or one or more tiles, in which each tile, for example, may have a rectangular shape and may contain one or more blocks (for example, CTUs ), such as full or fractional blocks.

It should be understood that in the encoder and decoder, the processing result of the current stage may be further processed and then output to the next stage. For example, after the interpolation filtering, motion vector output, or loop filtering, an additional operation such as limiting or shifting may be performed on the result of the interpolation filtering, motion vector output, or loop filtering processing.

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 intra prediction mode index values from 2 to 34 as shown by the black arrows in FIG. 4. To capture arbitrary edge directions present in natural video, the number of directional intrinsic modes has been expanded from 33 as used in HEVC to 65. Additional directional modes are indicated by dotted arrows in FIG. 4, and planar mode and DC mode remain unchanged. 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) is opposing, as shown in FIG. 4. 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).

Video coding schemes such as H.264/AVC and HEVC are developed based on 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, in the encoder, the video is usually processed, i.e. encoded, at the block (image block) level, for example, using spatial (inner image) prediction and temporal (outer image) prediction to generate a prediction block, subtracting the prediction block from the current block (the block currently being processed / to be processed) to obtain the residual block, transforming the residual block and quantizing the residual block in the transform domain to reduce the amount of data that must be transmitted (compressed), while in order to restore the current block for presentation in the decoder, inverse processing is partially applied compared to the encoder to the encoded or compressed block. In addition, the encoder duplicates the decoder's processing cycle so that both will generate identical predictions (eg, intra and inter prediction) and/or reconstructions for processing, i.e., encoding subsequent blocks.

As used herein, the term "block" may refer to a portion of an image or frame. For convenience of description, embodiments of the present invention are described herein with reference to High Efficiency Video Coding (HEVC) or Universal Video Coding (VVC) reference software developed by the Joint Collaborative Video Coding Group (JCT-VC) of the ITU-T Video Coding Expert Group ( VCEG) and the ISO/IEC Moving Picture Expert Group (MPEG). One of ordinary skill in the art will appreciate that embodiments of the present invention are not limited to HEVC or VVC. It may refer to CU, PU and TU. In HEVC, the CTU is divided into CUs using a square tree structure referred to as a coding tree. The decision as to whether to encode an image area using extrinsic (temporal) or intrinsic (spatial) prediction is made at the CU level. 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 the corresponding information is transmitted to the decoder based on the PU. After obtaining a 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 Quad Binary Tree (QTBT) Split Frame to split the coding block. In the block structure of QTBT, the CU can be 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 a binary tree are called coding units (CUs) and this segmentation is used to predict and process the transformation without any further separation. This means that CU, PU and TU have the same block size in the QTBT coding block structure. In parallel with the block structure of QTBT, 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 exploring the potential need to standardize a future compressible video coding technology that far exceeds the capabilities of the current HEVC standard (including 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 effort known as the Joint Video Exploration Team (JVET) to evaluate compression technology designs proposed by their experts in the field.

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

to accommodate an increased number of directional intra modes in the BMS, an intra mode coding method with 6 most likely modes (MPMs) is used. Two main technical aspects are used:

1) getting 6 MPMs, and

2) entropy encoding of 6 MPMs and non-MPM modes.

In BMS, the modes contained in the MPM lists are divided into three groups: neighbor inner modes, learned inner modes, and default inner modes.

Five adjacent intra prediction modes are used to form 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 original MPM list is formed by inserting 5 internal neighbor 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 the original modes are enabled is Left, Top, Flat, DC, Bottom Left, Top Right, and Top Left.

If the MPM list is incomplete (i.e. has less than 6 candidate MPMs in the list), learned modes are added, these internal modes are obtained by adding -1 or +1 to the angular modes already in the MPM list. The receive operation applies to non-angular modes, that is, 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 of the mode associated with the currently overfed bin. MPM mode falls into one of three categories: (a) whether the mode is 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 coding of the remaining 61 non-MPMs is performed 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 set of selected modes is generated by subsampling a total of 61 non-MPM modes 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 provides an overview of the various signaling mechanisms in INTRA mode.

Table 1. Current LUMA signaling in Intra mode in BMS

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

In another example, an INTRA mode coding method with 3 most likely modes (MPMs) is used. In the example, the syntax elements intra_luma_mpm_flag[x0][y0], intra_luma_mpm_idx[x0][y0], and intra_luma_mpm_remainder[x0][y0] 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, the intra prediction mode is output from the adjacent intra prediction block.

The intra prediction for the current block (IntraPredModeY [xPb] [yPb]) is obtained 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 performed using a location (xCurr, yCurr) set to (xPb, yPb) and an adjacent location (xNbY, yNbY) set to (xNbX, yNbX) as input, and the output indicates availableX availability.

• The intra prediction mode candidate canIntraPredModeX is derived as follows:

If one or more of the following conditions are true, candIntraPredModeX is set to INTRA_DC:

o AvailableX is FALSE.

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

o 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:

o 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

o Otherwise, candModeList [x] with x = 0..2 is obtained as follows:

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:

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

o candModeList[0] = candIntraPredModeA

o 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:

• Array candModeList [x], x = 0..2 is modified as follows:

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

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

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

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

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

o (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 aspect of the present invention, a simplified method for constructing an MPM list of 6 entries is provided.

According to an embodiment, in the first step, it is determined whether the left block of the current coding block is available or not. If the left block of the current coding block is available, the left block intra prediction mode is added to the MPM list. Determining whether a certain block is available will be described in detail below.

In the second step, it is determined whether the top block of the current coding block is available. If it is determined that the top block is available, the top block intra prediction mode is added to the MPM list.

As illustrated in FIG. 5, the left block L of the current coding block (current coding block) is a neighboring block of the current block. For example, it is located next to the current block at the bottom left of the current block. In addition, the upper block A of the current coding block (current coding block) is a neighboring block of the current block. For example, it is located next to the current block at the top right of the current block.

The third step adds an offset to the left block intra prediction mode and/or the top block intra prediction mode, provided that the left block and/or the top block is available and its mode is the angle intra prediction mode. The new prediction mode, determined by adding an offset to the prediction mode of the left and/or top block, is added to the MPM list.

Note that one new prediction mode can be defined by adding an offset to the left block prediction mode, one new prediction mode can be defined by adding an offset to the top block prediction mode, or new prediction modes can be defined by adding an offset to the left block prediction mode, and by adding an offset to the prediction modes of the upper block.

Also, note that the offset added to the left block prediction mode may be different from or equal to the offset added to the top block prediction mode.

In addition, the offset added to the left block prediction mode and/or the offset added to the top block prediction mode may be a positive or negative integer. In particular, the offset may be -1 or +1. However, the offset is not limited to +1 or -1 and can be any positive or negative integer.

In the case where the angular prediction modes are represented by a limited number of integers, the addition of an offset to the prediction mode may be performed cyclically, as detailed below in another embodiment.

According to the present invention, the above-described first and second steps are not limited to being performed in the described order, and the second step may be performed before the first step.

In addition, in the case where the left block and the top block are available, the present invention is not limited to adding an offset to the left block prediction mode and adding the resulting new prediction mode to the set of MPMs before adding the offset to the top block prediction mode and adding the resulting new prediction mode to the set MPMs. Adding an offset to the top block prediction mode may be performed before adding an offset to the left block prediction mode.

In an embodiment, the first offset may be added to the left block prediction mode and a new prediction block added to the list of MPMs. In addition, a second offset different from the first offset may be added to the left block prediction mode, and a (second) new prediction block is added to the list of MPMs.

Similarly, the first offset may be added to the top block prediction mode and a new prediction block added to the MPM list. In addition, a second offset different from the first offset may be added to the upper block prediction mode, and a (second) new prediction block is added to the list of MPMs.

Note that the MPM list is not limited to including three or four modes, and other modes may be added.

For example, a third offset may be added to the top block prediction mode and a new prediction mode added to the MPM list. In addition, a fourth offset different from the first offset may be added to the upper block prediction mode, and a (second) new prediction mode is added to the list of MPMs.

In another example, one or more offsets may be added to the left block intra prediction mode and/or the top block intra prediction mode, provided that the left block and/or the top block is available and its mode is an intra angle mode. The new one or more prediction modes, determined by adding one or more offsets to the left and/or top block prediction mode, are added to the MPM list.

In a further embodiment, the method comprises: (a) checking the availability of the left block of the current coding blocks. The position of the left block is shown in Fig. 5, where the left block is indicated by the letter "L".

The left block is unavailable if intra prediction information (ie, intra prediction mode) cannot be obtained from the left block. Which includes the following cases:

• The left block is not an intra prediction block; for example, the left block prediction mode may be an inter prediction mode.

• There is no left block, eg the current block is the coding block located on the leftmost side of the frame;

If the encoder or decoder supports parallel processing, the left block can be considered non-existent if it is located in a different tile than the current block, i.e., the current encoding block 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 a different tile than the current block, ie. the current coding block is located on the leftmost side of the tile;

• If parallel processing is supported in the encoder or decoder, the left block can be considered missing if it is located in a different segment than the current block, ie. the current coding block is located on the leftmost side 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 a different segment than the current block, i.e., the current encoding block is located on the leftmost side of the segment.

Otherwise (ie, the left block is available), (b) pad the MPM list with 6 entries with the left block intra prediction mode. Note that even though the MPM list may include six entries according to the embodiment, the present invention is not limited to this, and the MPM list may be a list of any length.

(c) Check the availability of the top block of the current coding block. The position of the top block is illustrated 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. For example, the left block prediction mode may be an inter prediction mode.

• The top block is missing. For example, the current block is the coding block located at the topmost side of the frame;

• If parallel processing is supported in the encoder or decoder, the top (ie, above) block may be considered non-existent if it is located in a different tile than the current block, ie. the current coding block is located at the topmost side of the tile.

In another example, if parallel processing is not supported in the encoder or decoder, the top (i.e., above) block may be considered available if it is located in a different tile than the current block, i.e., the current encoding block is located on the topmost side of the tile;

• If parallel processing is supported in the encoder or decoder, the top (ie, above) block may be considered non-existent if it is located in a different segment than the current block, ie. the current coding block is located at the topmost side of the segment.

In another example, if parallel processing is not supported in the encoder or decoder, the top (i.e., above) block may be considered available if it is located in a different segment than the current block, i.e. the current coding block is located at the topmost side of the segment;

If it is necessary to limit the size of the line buffer in the encoder or decoder, the top (i.e., above) block may be considered missing if it is located in a different CTU than the current block, i.e. the current coding unit is located at the topmost side of the current CTU.

In one example, if the decoder side or the encoder side supports the line buffer constraint, then an upper block located on a different CTU than the current CTU is considered to be missing. If the linear buffer constraint is not supported, then it is considered to be present.

Otherwise (ie, the top block is available), (d) turn on the intra prediction mode of the top (ie, top) block in the 6-entry MPM list.

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

(g) If the left block is available and its intra-prediction mode is angular mode, i.e., (mode > DC_IDX, and its mode is considered to be angularLeft), get its two nearest angular modes by doing angularLeft-1, angularLeft + 1. Note Note that when doing -1 or +1, this may include an increment and decrement operation. For example, if angularLeft is 2 then angularLeft-1 will be 66 (increase case) or if angularLeft is 66 then angularLeft + 1 will be 2 (decrease case).

In another example, if angularLeft is 2 then angularLeft-1 will be 65 (increment case) or if angularLeft is 66 then angulaLeft + 1 will be 3. Increment could be chosen as modes 2 and 66 indicate (anti)parallel directions . In this case, the next two angular modes angularLeft can be computed as angularLeft-1 = 2 + ((angularLeft + 61)% 64); and

angularLeft + 1 = 2 + ((angularLeft -1)% 64).

These calculation rules correspond to adding an offset of -1 or +1, respectively, with magnification and modes 0 and 1, which are not angular prediction modes. % displays modulo operation.

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

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

(j) If the MPM list is incomplete, if the top block is available and if its (top block) intra prediction mode is angular mode, i.e., (mode > DC_IDX, and the mode is considered to be angularAbove), get its next two angular modes doing angularAbove-1, angularAbove + 1. Note that when doing -1 or +1 this may include an increment and decrement operation.

In the example, if angularAbove is 2 then angularAbove-1 will be 66 (increase case) or if angularAbove is 66 then angularAbove + 1 will be 2 (decrease case).

In another example, if angularAbove is 2 then angularAbove-1 will be 65 (increase case) or if angularAbove is 66 then angulaAbove + 1 will be 3. This increase can be chosen as modes 2 and 66 indicate (anti)parallel directions . In this case, the next two angular modes of angularAbove can be calculated as

angularAbove-1 = 2 + ((angularAbove + 61)% 64); and

angularAbove + 1 = 2 + ((angularAbove -1)% 64).

These calculation rules correspond to adding an offset of -1 or +1, respectively, with magnification and modes 0 and 1, which are not angular prediction modes. % displays modulo operation.

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

(l) If the MPM list is incomplete (e.g. the number of prediction modes in the MPM list is less than 6) and if the prediction mode angularAbove + 1 has not been inserted into the MPM list, insert it (angularAbove + 1) into the MPM list.

(m) 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);

Note that the definition of nearest neighbor modes detailed within this embodiment may also apply to other embodiments.

In the described embodiments, the MPM list is a finite length list. For example, the length of the list (ie, the number of entries) may be predetermined. For example, the number of entries in the MPM list may be six. However, the MPM list is not limited to six entries and may include a different number of entries.

The following is a summary of the variations of the method provided:

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 getting the two closest modes of the left and top block can also be first +1 and then -1. Thus, the nearest modes of the left and upper blocks can be determined first by adding 1 to the corresponding mode index, and then by subtracting 1 from the corresponding mode index.

The last candidate in the MPM list may be VIDA_IDX or DIA_IDX, as illustrated in FIG. 6.

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 with a CABAC pass.

In one aspect of the present invention, a method for constructing a list of the most likely mode, MPM, 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 original MPM list, adding the planar mode to the MPM list; if the DC mode is not in the original MPM list, add the DC mode to the MPM list.

In one aspect of the present invention, a method for constructing a list of the most likely mode, MPM, 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; adding an offset to at least one of the left block prediction mode and the top block prediction mode to obtain at least one new prediction mode if at least one of the left block of the current block and the top block of the current block is available , and the intra prediction mode of at least one of the left block and the top block is an angle mode; and adding at least one new prediction mode to the MPM list if at least one new prediction mode is not in the MPM list.

A method for constructing a list of the most probable mode, MPM, is provided, in which 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; adding an offset to the left block prediction mode to obtain a new prediction mode if the left block of the current coding block is available and the left block intra prediction mode is an angular mode; and adding a new prediction mode to the MPM list if the new prediction mode is not in the MPM list; and/or adding an offset to a top block prediction mode to obtain an offset-top prediction mode if the top block of the current coding block is available and the top block intra prediction mode is an angle mode; and adding the offset-up prediction mode to the MPM list if the offset-up prediction mode is not in the MPM list.

In other words, either (i) a new prediction mode obtained by adding an offset to the prediction mode of the left block of the current block is added to the MPM list, or (ii) a new prediction mode (offset-up prediction mode) obtained by adding an offset to the prediction mode top block of the current block is added to the MPM list, or (iii) a new left block prediction mode of the current block and an additional new prediction mode (offset-top prediction mode added to the MPM list). In each case, a new prediction mode and/or offset-top prediction mode is added to the MPM list if it is not already present in the MPM list and if the left or top block, respectively, is available and their prediction modes are intra-angular prediction modes.

Note that the MPM list is not necessarily extended in the manner described above, and additional prediction modes may be added. For example, one or more offsets may be added to the left block intra prediction mode and/or the top block intra prediction mode. The new one or more prediction modes, determined by adding one or more offsets to the left and/or top block prediction mode, are added to the MPM list.

Note that the order of adding the new prediction mode and the offset-up prediction mode is not limited to first adding the new prediction mode and then adding the offset-up prediction mode, but can be switched, i.e., first adding the offset-up prediction mode and then adding new prediction mode.

In an example in which, when the left block prediction mode is not intra prediction mode, the left block of the current coding block is unavailable. For example, in the case where the left block prediction mode is the inter prediction mode, the left block of the current coding block is unavailable.

In an example in which, when the current coding block is the coding block located at the leftmost side of the frame, the left block of the current coding block is unavailable. That is, in the case where there is no left block, since the current block is the leftmost block in the current frame, the left block is not available.

In an example where parallel processing is supported and the current coding block is the coding block located on the leftmost side of the tile, the left block of the current coding block is not available.

In an example where parallel processing is not supported and the current coding block is the coding block located on the leftmost side of the tile, the left block of the current coding block is available. In other words, even when the left block of the current encoding block is located in a different tile, it can be considered available if the encoder or decoder does not support parallel processing.

In an example where parallel processing is supported and the current coding block is the coding block located on the leftmost side of the segment, the left block of the current coding block is not available.

In an example where parallel processing is not supported and the current coding block is the coding block located on the leftmost side of the segment, the left block of the current coding block is available. In other words, even when the left block of the current coding block is located in a different segment, it can be considered available if the encoder or decoder does not support parallel processing.

In an example in which, when the top block prediction mode is not an intra prediction mode, the top block of the current coding block is unavailable. For example, in the case where the top block prediction mode is the inter prediction mode, the top block of the current coding block is unavailable.

In an example in which, when the current coding block is the coding block located at the topmost side of the frame, the top block of the current coding block is unavailable. That is, in the case where the top box is missing because the current box is the topmost box in the current frame, the left box is not available.

In an example where parallel processing is supported and the current coding block is the coding block located at the topmost side of the tile, the top block of the current coding block is not available.

In an example where parallel processing is not supported and the current coding block is the coding block located at the topmost side of the tile, the top block of the current coding block is available. In other words, even when the top block of the current encoding block is located in a different tile, it can be considered available if the encoder or decoder does not support parallel processing.

In an example in which parallel processing is supported and the current coding block is the coding block located at the topmost side of the segment, the top block of the current coding block is not available.

In an example where parallel processing is not supported and the current coding block is the coding block located at the topmost side of the segment, the top block of the current coding block is available. In other words, even when the top block of the current coding block is located in a different segment, it can be considered available if the encoder or decoder does not support parallel processing.

In one example, when the size of the line buffer needs to be limited and the current coding unit is a coding unit located on the topmost side of the current CTU, the top block of the current coding unit is not available.

In an example, the method further comprises: if the left block of the current coding block is available and the left block 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 original MPM list, adding a new prediction mode in the MPM list.

In the example where the offset is -1.

In the example where the offset is +1.

In an example, the method further comprises: if the top block of the current coding block is available and the top block prediction mode is corner mode, adding an offset to the top block prediction mode to obtain an offset-top prediction mode, if the offset-top prediction mode is not in the original MPM list, adding bias-top prediction mode to the MPM list.

In the example where the offset is -1.

In the example where the offset is +1.

In the example, the method further comprises: adding 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.

In one aspect of the present invention, an encoder is provided that contains a processing circuit for performing any of the above methods.

In one aspect of the present invention, a decoder is provided, comprising a processing circuit for performing any of the above methods.

In one aspect of the present invention, a computer program product is provided that contains program code for performing any of the above methods. For example, a computer program product contains an instruction that, when the program is executed by a computer or processor, causes the computer to perform the steps of any of the above methods.

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

In one aspect of the present invention, an encoder is provided for constructing a most likely mode list, MPM, 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 when the program is executed by the processors, configuring the encoder to perform any of the above methods.

The present invention provides an improvement in the intra prediction mode signaling scheme. In the present invention, a video decoding method and a video decoder are provided.

A video decoding method, comprising: decoding the encoded image block data to obtain an intra prediction mode from a plurality of intra prediction modes for the image block, the plurality of intra prediction modes for the image block contains a set of most probable modes, MPM, and a set of non-MPM, in which the set of non- The MPM comprises a first intra prediction mode set and a second intra prediction mode set, wherein one mode in the first intra prediction mode set is encoded using N bits, one mode in the second intra prediction mode set is encoded using M bits, N and M are positive integers numbers, N less than M, wherein decoding the encoded data to obtain an intra prediction mode from a plurality of intra prediction modes for an image block, comprising: decoding the encoded data to obtain an indication indicating whether the intra prediction mode is its prediction for an image block in the set of MPMs or not; if an indication indicating the intra prediction mode for the image block is not included in the set of MPMs, 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- MPM; decoding the encoded data to obtain an intra prediction mode codeword for the image block; obtaining an 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 non-MPM set and a mapping relation is generated, therefore, the prediction mode for the current block has a higher coding probability using fewer bits, and the computational complexity is reduced on the decoder side.

In one embodiment of the present invention, the method further comprises receiving encoded image block data. In one example, the encoded data is received by the decoder side before decoding the encoded data. In the example, encoded data is received by the receiver.

In one implementation form of the present application, the number of the plurality of intra prediction modes for an image block is 67, the plurality of intra prediction modes of 67 intra prediction modes, containing: planar mode (value 0), DC mode (value 1 ), and angular modes with values from 2 to 66. The number of multiple intra prediction modes for a picture block may be other values such as 35, 48, 71, and so on.

In the example, the number of the set of MPMs is 6, the number of the non-MPM set is 61, the number of the first set of intra prediction modes is 3, and the number of the second set of intra prediction modes is 58.

In another example, the number of the set of MPMs is 3, the number of the non-MPM set is 64, the number of the first set of intra prediction modes is 3 or 6, and the number of the second set of intra prediction modes is 61 or 58.

In the example N = 5, M = 6; in another example N = 2, M = 6.

In one embodiment of the present invention, each mode in the first intra prediction mode set is encoded using N bits, each mode in the second intra prediction mode set is encoded using M bits.

In one example, the intra prediction modes in the first intra prediction mode set are encoded using a truncated binarization scheme, at least one mode in the first intra prediction mode set is encoded using N bits, and at least one mode in the first intra prediction mode set encoded using less than N bits.

In one implementation form of the present application, an indication indicating the intra prediction mode for the image block is in the MPMs set or not, is 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 equal to 0 may indicate that the intra prediction mode for the image block is not included in the set of MPMs. For example, on the encoder side, if the MPM list is a set of internal modes, say: [20,40, 60] and the current block internal mode value is 40, then the MPM flag indication is set to 1 as the internal mode for the current block is in the second entry MPM list. If, for example, the current internal block mode is 41 instead of 40, then the indication of the MPM flag is set to 0, the MPM flag is sent to the decoding side in the encoded data.

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

If intra_luma_mpm_flag[xPb][yPb] is 1 (indicating that the intra-prediction mode for the image block is in the MPMs set), IntraPredModeY[xPb][yPb] is set to candModeList[intra_luma_mpm_idx[xPb][yPb]], where (xPb, yPb) indicates the upper left sample of the current luma prediction block relative to the upper left luma sample of the current image, and candModeList is the actual MPM list decoding the encoded data to obtain an MPM index, obtaining an 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 image block intra prediction mode is angle mode 21.

In one embodiment of the present invention, wherein one of the at least one intra prediction mode in the first intra prediction mode set corresponds to one of the at least one intra prediction mode in the non-MPM set.

2, 25

3, 6

4.In the example, the prediction modes in the first intra prediction mode set are (17, 25, 6) and the mapped prediction modes in the non-MPM set are (2, 3, 4), 17

2.25

3, 6

four.

2, 16

3, 28

4.In another example, the prediction modes in the first intra prediction mode set are (2, 16, 28) and the mapped prediction modes in the non-MPM set are (2, 3, 4), 2

2, 16

3, 28

four.

3.In another example, the prediction modes in the first intra prediction mode set are (28) and the mapped prediction modes in the non-MPM set are (3), 28

3.

In one form of implementation of the present invention, in which the mapping relationship is generated according to a set of MPMs.

In one embodiment of the present invention, a mapping relation is generated according to a classification of prediction modes in a set of MPMs.

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

In the example, 5 categories of 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 in which the angular intra prediction mode of the list of most likely modes falling into each category of the angular intra prediction mode, for example, corresponds to associating each of the angular intra prediction modes of the list of most likely modes with the angular intra prediction mode category closest to the corresponding angular intra prediction mode of the most likely list. possible modes. In another example, repeating this step from the second highest category of the angular intra prediction mode.

In one embodiment of the present invention, wherein generating a mapping relationship between an intra prediction mode in a first set of intra prediction modes and an intra prediction mode in a second set of intra prediction modes, comprising: generating an initial set of intra prediction modes according to adding an offset to the set of values corresponding to the set 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 original intra prediction mode set.

In one form of implementation of the present invention, in which the original set of intra prediction modes is generated according to the addition of an offset of -1, +1, +2, -2, +3, -3, +4, or -4 to the set of values corresponding to the set of MPMs.

In one form of implementation of the present invention, in which the display relationship is generated according to a predetermined 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).

In FIG. 6 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 2-66, in in which the lower left corner mode in FIG. 6 refers to index 2, and the index numbering is incremented until index 66 is the uppermost right corner mode in FIG. 6.

The example proposes an intra mode signaling scheme with 6 MPMs and a remaining 61 modes, in which the remaining 61 modes are encoded using a truncated binarization scheme. The remaining 61 internal modes can also be encoded using a 6-bit fixed-length code, but the disadvantage of a 6-bit fixed-length code is that out of 64 possible codewords, only 61 codewords are used, and the remaining 3 codewords are not used. Instead of a fixed length code, a truncated binarization is proposed which will only use 5 bits to signal the first 3 remaining modes and the remaining 58 modes are then encoded using 6 bits.

Truncated binarization always allows smaller codewords to be transmitted using fewer bits compared to larger codewords. For example, as shown in FIG. 6, horizontal modes beginning with “internal modes 2, 3, 4…” are most commonly transmitted using 5 bits. Therefore, for efficient signaling of the remaining modes (non-MPM modes), the first few non-MPM codewords are mapped to received modes that are more likely. For example, the size of the MPM list is 6, and the internal modes that are included in the MPM list are [18, 30, 0, 1, 66, 24], then the first three modes in the non-MPM modes, which require only 5 bits for signaling are modes [2,3,4]. Let's say modes [2, 3, 4] are called "internal codeword modes". Since modes 2, 3, 4 may not always be high probability modes, these modes are mapped to representations of the other three internal modes, which are more likely. For example, let's say after the 6 most likely modes in MPMs, the other three modes that are more likely have mode numbers [19, 17, 21]. Let's say the modes [19, 17, 21] are called "derived non-MPM modes". Then an easy way to make sure modes 19, 17, 21 use only 5 bits is to map internal modes [2, 3, 4] to internal modes [19, 17, 21]. Essentially, the encoder maps and signals intra modes 19 to intrinsic mode 2, and then the decoder demaps and maps intrinsic mode 2 to intrinsic mode 19. Moreover, this simple mapping reduces the number of clipping operations for signaling non-MPM modes by compared to signaling non-MPM modes using a list and specifying an index in the list. In a special case, if the "received non-MPM modes" and the "internal codeword modes" with the smallest codeword have overlap, then it is guaranteed that the common internal mode for both lists is displayed together. For example, if "internal codeword modes" are [2, 3, 4] and the list of "received non-MPM modes" is [2, 4, 17], then internal mode 2 is mapped to internal mode 2, mode 3 is mapped to mode 17 and mode 4 is mapped to mode 4.

Several solutions have been proposed to populate the first three modes of the list of remaining modes.

The first three modes in the remaining list of modes can be filled in several ways.

First, using modes from a predefined list of default modes, which includes {planar mode (PLANAR_IDX), DC mode (DC_IDX), vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 (2), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX)} (terms in brackets indicate the corresponding terms in Fig. 6, more details on Fig. 6 are given below);

Secondly, with the help of shifting angular modes, which are already present in the MPM list. Here the offset can be +/- N, where N is a possible integer value whose value is {1, 2, 3, 4}. Offsets could only be added to the first two angular modes from the MPM list.

Third, the internal modes of non-adjacent neighbors can also be used to populate the three modes. As shown in FIG. 7, internal neighbor modes of the second layer may be used.

Fourth, as shown in FIG. 6, in the first step, a given mode is selected from the MPM list and checked if it is "near" one of the following mode categories {DC_IDX, HOR_IDX, DIA_IDX, VER_IDX, VDIA_IDX}, in the second step, the mode categories are then "sorted" based on " most" regimes that are close to them. The third step generates a list of the remaining modes by inserting the modes that are next to the winning mode category from step 2.

In one embodiment of the present invention, wherein 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-MPM set, comprising: a set of values according to with prediction mode values in the set of MPMs, one value in the first set of values is the smallest prediction mode value in the non-MPM set; generating a second set of values according to adding an offset to a value of at least one prediction mode in the set of MPMs; generating a display relationship according to the first set of values and the second set of values.

In one form of implementation of the present invention, the decoder side first obtains the MPM set for the current block, the generation process may refer to the corresponding part in ITU H.264, ITU H.265, or the above description of constructing candModeList. After receiving the MPM set, the decoder side selects the smallest prediction mode value in the non-MPM set as one value in the first value set.

In the example, the first set of values contains the three smallest values in the non-MPM set, if the values of the prediction modes in the MPM set are (0, 1, 3, 5, 8, 10), then the first set of values is (2, 4, 6) .

In another example, the first set of values contains the two smallest values in the non-MPM set, if the values of the prediction modes in the MPM set are (0, 1, 3, 5, 8, 10), then the first set of values is (2, 4).

In one example, an offset of -1, +1, +2, -2, +3, -3, +4, or -4 is added to the set of values corresponding to the set of MPMs.

In one embodiment of the present invention, wherein 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-MPM set, comprising: a set of values according to with prediction mode values in the set of MPMs, one value in the first set of values is the smallest prediction mode value in the non-MPM set; generating a second set of values in accordance with adding an offset to a value of at least one angle prediction mode in the set of MPMs; generating a display relationship according to the first set of values and the second set of values.

In the example, an offset of -1, +1, +2, -2, +3, -3, +4 or -4 is added to at least one value corresponding to at least one angle prediction mode in the set of MPMs.

In another example, an offset of -1, +1, +2, -2, +3, -3, +4, or -4 is added to the values corresponding to the two angle prediction modes in the set of MPMs.

In one embodiment of the present invention, the number of prediction modes in the set of intra prediction modes for an image block is 67, the number of prediction modes in the set of MPMs is 6, the number of prediction modes in the first set of intra prediction modes in the non-MPM set is 3, and the number of prediction modes in the second set of intra prediction modes in the non-MPM set is 58, wherein the generation of 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 non-MPM set an MPM comprising: obtaining the lowest three values of the three prediction modes in the non-MPM set according to the prediction mode values in the MPMs set; obtaining two values of two angle prediction modes in the set of MPMs, adding an offset to the two values to obtain offset values; obtaining a second set of values according to the values of the prediction modes in the set of MPMs and the offset values; generating a display relationship according to the first set of values and the second set of values.

In one embodiment of the present invention, wherein 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-MPM set, comprising: a set of values according to with prediction mode values in the set of MPMs, one value in the first set of values is the smallest prediction mode value in the non-MPM set; generating a second set of values according to a predefined default mode list comprising or consisting of vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 (2), vertical diagonal mode (VDIA_IDX), and diagonal mode (DIA_IDX); generating a display relationship according to the first set of values and the second set of values.

In the example, an offset of -1, +1, +2, -2, +3, -3, +4, or -4 is added to at least one value corresponding to at least one prediction mode in a predetermined list of modes default.

In the example, an offset of -1, +1, +2, -2, +3, -3, +4 or -4 is added to at least one value corresponding to at least one angle prediction mode in a predefined list default modes.

In one example, an offset of -1, +1, +2, -2, +3, -3, +4, or -4 is added to two values corresponding to two angle prediction modes in a predetermined list of default modes.

In one embodiment of the present invention, wherein 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-MPM set, comprising: a set of values according to with prediction mode values in the set of MPMs, one value in the first set of values is the smallest prediction mode value in the non-MPM set; generating a second set of values according to a predefined list of default modes, containing or consisting of planar mode (PLANAR_IDX), DC mode (DC_IDX), vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 (2), vertical - diagonal mode (VDIA_IDX) and diagonal mode (DIA_IDX); generating a display relationship according to the first set of values and the second set of values.

In one embodiment of the present invention, in which the intra prediction mode codeword is encoded using 5 bits, and the intra prediction mode codeword is one of 00000, 00001, or 00010.

In the example, the decoding side decodes the codeword to obtain the original value, for example, if the codeword is 00001, then the original value is 1.

Then compare the original value with each value corresponding to the prediction mode in the MPMs set, if the original value is greater than or equal to the value corresponding to the prediction mode in the MPMs set, increase the original value by one, repeat this step until all values in the MPMs set are compared with original value and will not receive the final value.

For example, to adjust the values corresponding to a set of MPMs in ascending order, the adjusted values corresponding to a set of MPMs will be (0, 1, 4, 6, 8, 10); the codeword is 00001, in the first step, since 1 is greater than the first value corresponding to the set of MPMs, this initial value of 1 is increased by one and the correction value is 2; in the second step, since 2 is greater than the second value corresponding to the set of MPMs, another correction value of 3 is obtained by incrementing from one to 2; and since 3 is less than the third value corresponding to the set of MPMs, the final value is 3. And, if the end value of 3 is not in the display set, the end value of 3 is the value corresponding to the intra prediction mode of the image block, so the intra prediction mode of the image block is angular mode 3.

If the end value 3 is in the display set, the display value (for example, 17) is the value corresponding to the intra prediction mode of the image block, so the intra prediction mode of the image block is angle mode 17. In some examples, the display value may be the same as the end value, for example, if the end value 3 is in the display set, then the display value is also present, so the image block intra prediction mode is angular mode 3.

In another aspect of the present invention, a decoder is provided, comprising a processing circuit, for performing the above decoding methods.

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

In another aspect of the present invention, a decoder for decoding video data is disclosed, wherein the decoder comprises: 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, when the program is executed by the processors, configures the decoder to perform the above decoding methods.

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

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

when obtaining an intra prediction mode of an image block from a plurality of intra prediction modes, the plurality of intra prediction modes for an image block comprises a set of most likely modes, an MPM, and a non-MPM set, in which the non-MPM set comprises a first intra prediction mode set and a second intra prediction mode set. predictions;

if the intra prediction mode of the image block is in the non-MPM set, 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-MPM set;

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 invention in the following detailed description of a part of the embodiments, or to a relative invention in the field of video coding technology such as in ITU-T H.264, ITU-T H .265.

In one form of implementation of the present invention, the coding 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 picture block is not in the set of MPMs, then the intra prediction mode of the picture block is in the set of non-MPMs.

The process of generating a set of MPMs may refer to a relative invention in the description part or a relative invention 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 the first intra prediction mode set and at least one intra prediction mode in the non-MPM set may relate to a relative invention on the decoding side.

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

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

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

In another aspect of the present invention, an encoder for encoding video data is provided, wherein the encoder comprises: 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, when the program is executed by the processors, configuring the encoder to perform the aforementioned encoding methods.

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

In one embodiment of the present invention, as shown in FIG. 8, the present invention discloses a video decoding method comprising:

S801: decoding the 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 contains a set of most likely modes, MPM, and a set of non-MPM, in which the set of non-MPM contains the first set of intra prediction modes and the second set of intra prediction modes, in which one mode in the first set of intra prediction modes is encoded using N bits, one 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,

Decoding encoded data to obtain an intra prediction mode from a plurality of intra prediction modes for an image block (S801), comprising:

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 an indication indicating that the intra prediction mode for the image block is not included 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-MPM set;

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

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

According to the video decoding method of the present invention, a truncated binarization scheme in a non-MPM set can be used to encode prediction modes, and a mapping relation is generated, therefore, the prediction mode for the current block has a higher probability of using fewer bits in encoding, and the computational cost is reduced at the decoder side. complexity.

In one embodiment of the present invention, as shown in FIG. 9, the present invention discloses a video decoding method comprising:

S901: receive encoded picture block data;

The decoder side may be configured to receive 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 or public network, or any combination of them.

S902: decode 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 set of MPMs or not may be a flag. When the flag value is 1, it may indicate that the intra prediction mode for the image block is in the MPMs set, when the flag value is 0, it may indicate that the intra prediction mode for the image block is not in the MPMs set. For example, on the encoder side, if the MPM list (set of MPMs) is the set of intrinsic modes [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 because the intrinsic mode for the current block is in the second entry. MPM list. If, for example, the internal mode of the current block is 41 instead of 42, then the indication of the MPM flag is set to 0, the MPM flag is sent to the decoder side in the encoded data.

If an indication indicating the intra prediction mode for the image block is in the set of MPMs, execute step S903.

If an indication indicating the intra prediction mode for the image block is not present in the set of MPMs, execute step S904.

S903: decode 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:

If intra_luma_mpm_flag [xPb] [yPb] is 1 (indicating that the intra prediction mode for the image block is in the MPMs set), IntraPredModeY [xPb] [yPb] is set equal 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, decode the encoded data to obtain the MPM index, obtain 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 MPM index value is 5, so the intra prediction mode of the image block is angle mode 21. The MPM index indicates the position of the intra prediction mode for the image block in the set MPMs.

S904: 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-MPM set;

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

For example, the first list of codewords 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 Mc mode candidate as (Ms + Inc), check if Mc mode is also in MPM list.

if Mc is not 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 filled, complete the operation;

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

To sum up, the list of codewords will contain the smallest modes other than those present in the MPM list. Given that the length of the MPM list is L, 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 generated codeword is (2, 3, 4).

The second list of received modes is constructed as follows:

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

2. Set the initial increment variable Inc = 1.

3. Get new mode M0 _minus = angular0 - Inc. Note M0 _minus must also guarantee the angular operation (ie 66>= M0 _minus >= 2). Therefore, if angular0 is 2, Inc is 1; then the resulting M0 _minus will be equal to 66; if Inc is 2, then M0 _minus is 65, and so on. The minus operation will complete before the maximum angular mode.

4. Check if M0 _minus is 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 full, stop.

Otherwise, go to step 5.

5. Get new mode M0 _plus = angular0 + Inc. Please note that M0 _plus must also be guaranteed angular mode (i.e. 66 >= M0 _plus >= 2). Therefore, if angular0 is 66, Inc is 1, then M0 _plus will be 2, if Inc is 2, then M0 _plus will be 3, and so on. The plus operation will complete before the minimum angular mode.

6. Check if M0 _plus is 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 full, stop.

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 compiled list of received modes is (14, 16, 35).

14, 3

16 и 3

35, где

представляет собой двунаправленное отображение.When the list of codewords and the list of received modes are compiled, a bidirectional mapping relation is generated 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), the bidirectional mapping is 2

14, 3

16 and 3

35, where

is a bidirectional display.

Two options are used to build a bidirectional mapping relationship between a list of codewords and a list of received modes. The first option is that the list of received modes can be constructed in such a way that elements can exist both in the list of received modes and in the list of codewords. Another option is that the list of received modes cannot overlap with the modes in the codeword list.

In another example, in one implementation form of the present invention, 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-MPM set, comprising: ranking a set intra prediction mode categories according to the number and/or direction of intra prediction modes in the set of MPMs found in 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 angular intra prediction modes, namely, vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra mode 2 (2), vertical diagonal mode (VDIA_IDX), and diagonal mode DIA_IDX. The angular intra prediction mode of the list of most likely modes falling into each category of the angular intra prediction mode, for example, corresponds to the association of each of the angular intra prediction modes from the list of most likely modes with the angular intra prediction mode category closest to the corresponding angular intra prediction mode of the list of most likely possible modes. In another example, repeating this step with the second highest category of the angular intra prediction mode.

In an example, in which generating a mapping relationship between an intra prediction mode in the first intra prediction mode set and an intra prediction mode in the second intra prediction mode set, comprising: generating an initial intra prediction mode set according to adding an offset to a set of values corresponding to the 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 original intra prediction mode set.

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.

In the example, the display relationship is generated 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: decode 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 coding side. In one example, since the relationship is bidirectional mapping, the intra prediction mode corresponding to the codeword can be mapped to another intra prediction mode in the non-MPM set.

S906: Obtain the intra prediction mode for the image block according to the display ratio and the intra prediction mode codeword.

In the example, after generating a bidirectional mapping relationship, check if the received 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 both the codeword list and 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 to its corresponding mapped intra prediction mode.

4, 5

5 и 6

65.If the parsed intra prediction mode is present in both the codeword list and the acquired mode list, a mechanism is introduced into the construction operation of the two lists so that the bidirectional mapping relationship is adjusted and all overlapping modes are mapped onto themselves in the other list. Example: MPM list is (0 1 2 3 50 66), codeword list is (4 5 6), received mode list is (4 65 5). When constructing a list of received modes or a list of codewords, we check 4

4, 5

5 and 6

65.

In addition, a decoder is provided containing a processing circuit for performing the above methods.

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

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

In the present invention, a video decoding method and a video decoder are provided. A video decoding method, comprising: receiving encoded image block data of an encoding block; decoding the encoded data to identify an intra prediction mode from the plurality of intra prediction modes for the image block, the plurality of intra prediction modes comprises a set of most probable modes, MPM, a first set of intra prediction modes, and a second set of intra prediction modes, in which one mode in the first set of intra prediction modes prediction is encoded using N bits, one 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, which contains: decoding the encoded data to obtain an indication indicating whether the intra prediction mode is for an image block in the MPMs set or not; if the indication indicating the intra prediction mode for the image block is not included in the set of MPMs,

obtaining an intra prediction mode codeword for an image block in which the intra prediction mode codeword corresponds to the original intra prediction mode;

if the intra prediction mode codeword for the image block is encoded using N bits, mapping the original intra prediction mode to obtain a mapped intra prediction mode using the mapped intra prediction mode as the identified intra prediction mode for the image block;

and, if the intra prediction mode codeword for the image block is encoded using M bits, using the original intra prediction mode as the identified intra prediction mode for the image block.

In one embodiment of the present invention, the number of the plurality of intra prediction modes for an image block is 67, the plurality of intra prediction modes of 67 intra prediction modes, comprising: planar mode (value 0), DC mode (value 1), and angular modes with indices from 2 to 66.

In the example, the number of the set of MPMs is 6, the number of the first set of intra prediction modes is 3, and the number of the second set of intra prediction modes is 58.

In another example, the number of the MPM set is 3, the number of the first intra prediction mode set is 3 or 6, and the number of the second intra prediction mode set is 61 or 58.

In one embodiment of the present invention, each mode in the first intra prediction mode set is encoded using N bits, each mode in the second intra prediction mode set is encoded using M bits.

In one example, the intra prediction modes in the first intra prediction mode set are encoded using a truncated binarization scheme, at least one mode in the first intra prediction mode set is encoded using N bits, and at least one mode in the first intra prediction mode set encoded using less than N bits.

In one example, an indication indicating whether the intra prediction mode for an image block is in the MPMs set or not is 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 the intra prediction mode for the image block is not included in the set of MPMs.

In an example, an indication indicating that the intra prediction mode for the image block is in the MPMs set or is not 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 the intra prediction mode for the image block is not included in the set of MPMs. For example, on the encoder side, if the MPM list is a set of internal modes, say: [20,40, 60] and the current block internal mode value is 40, then the MPM flag indication is set to 1, the internal mode for the current block is in the second entry MPM list. If, for example, the current internal block mode is 41 instead of 40, then the MPM flag indication is set to 0.

In one example, if an indication indicating the intra prediction mode for an image block is in a set of MPMs. The acquisition process is defined as follows: IntraPredModeY [xPb] [yPb] is obtained by applying the following procedure: if intra_luma_mpm_flag [xPb] [yPb] is equal to 1, IntraPredModeY [xPb] [yPb] is set equal 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. For example, decoding the encoded data to obtain an MPM index, obtaining an intra prediction mode of an image block according to the MPM index and the MPM set. 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.

In one example, the intra prediction mode codeword for the image block decodes the encoded data accordingly. If an intra prediction mode codeword for an image block is encoded using M bits, using the original intra prediction mode as the identified intra prediction mode for the image block. For example, M is 6 if the intra prediction mode codeword is encoded as 010011 (e.g., 6 bits), which corresponds to angle mode 19, hence the identified intra prediction mode for the image block is angle mode 19.

In one form of implementation of the present invention, if an indication indicating the intra prediction mode for an 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 Ms mode candidate as (Ms + Inc), check if Ms mode is also in MPM list.

if Ms is not in the MPM list, add Ms 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 sum up, the list of codewords will contain the smallest modes other than those present in the MPM list. Given that the length of the MPM list is L, 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 constructed as follows:

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

2. Set the initial increment variable Inc = 1

3. Get new mode M0 _minus = angular0 - Inc. Note M0 _minus must also guarantee the angular operation (ie 66>= M0 _minus >= 2). Therefore, if M0 _minus is equal to 2, Inc is equal to 1; then the resulting M0 _minus will be 66; if Inc is 2, then M0 _minus is 65, and so on. The "minus" operation will end before the maximum angular mode.

4. Check if M0 _minus is 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 full, stop.

Otherwise, go to step 5.

5. Get new mode M0 _plus = angular0 + Inc. Note. M0 _minus must also guarantee angular operation (i.e. 66 >= M0 _minus >= 2). Therefore, if angular0 is 66, Inc is 1, then M0 _minus will be 2, if Inc is 2, then M0 _minus will be 3, and so on. The plus operation will complete before the minimum angular mode.

6. Check if M0 _minus is 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 full, stop.

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. Given 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 will be (14, 16, 35).

14, 3

16 и 3

35, где

представляет двунаправленный отображение.When a list of codewords and a list of received modes are compiled, a bidirectional mapping relationship is built 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 a bidirectional mapping.

After building the bidirectional mapping relation, it is checked whether the received intra prediction mode is in the list of codewords or in the list of derived modes:

If the parsed intra prediction mode is not in both the codeword list and 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 to its corresponding mapped intra prediction mode.

4, 5

5 и 6

65.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 adjusted and all overlapping modes are mapped onto themselves in the other list. Example: MPM list is (0 1 2 3 50 66), codeword list is (4 5 6), received mode list is (4 65 5). When constructing a list of received modes or a list of code words, make sure that 4

4, 5

5 and 6

65.

In one embodiment of the present invention, an intra prediction mode codeword for a picture block is provided in accordance with decoding of encoded data. If the intra prediction mode codeword for the image block is encoded using N bits, mapping the original intra prediction mode to obtain the mapped intra prediction mode using the mapped intra prediction mode as the identified intra prediction mode for the image block. For example, N is 5 if an intra prediction mode codeword is encoded as 00011 (e.g., 5 bits), which corresponds to angle mode 3, in this example, the initial intra prediction mode is angle mode 3, the mapped intra prediction mode may be DC mode (previously defined value 1) or angle mode 47; in another example, the mapped intra prediction mode may be the same as the original prediction mode, for example, the mapped intra prediction mode is also angle mode 3.

The example shows an intra mode signaling scheme with 6 MPM and 61 remaining modes, in which the remaining 61 modes are encoded using a truncated binarization scheme. The remaining 61 intra modes can also be encoded using a 6-bit fixed-length code, but the disadvantage of a 6-bit fixed-length code is that out of 64 possible codewords, only 61 codewords are used, and the remaining 3 codewords are not used. Instead of a fixed length code, a truncated binarization is proposed that will only use 5 bits to signal the first 3 remaining modes, and the remaining 58 modes are then encoded using 6 bits.

Truncated binarization allows smaller codewords to be transmitted using fewer bits compared to larger codewords. For example, as shown in FIG. 4, horizontal modes beginning with “internal modes 2, 3, 4…” are most often transmitted using 5 bits. Therefore, for efficient signaling of the remaining modes (non-MPM modes), the first few non-MPM codewords are mapped to received modes that are more likely. For example, the size of the MPM list is 6 and the internal modes that are in the MPM list are [18, 30, 0, 1, 66, 24], then the first three modes in the non-MPM modes that require only 5 bits for signaling , are the modes [2,3,4]. Modes [2, 3, 4] are called "internal codeword modes". Because modes 2, 3, 4 may not always be high probability modes, these modes are displayed to represent three other internal modes that are more likely. For example, after the 6 most likely modes in MPM, the other three modes that are more likely have mode numbers [19, 17, 21]. The modes [19, 17, 21] are referred to as "non-MPM derived modes". Then an easy way to make sure that modes 19, 17, 21 consume only 5 bits is to map internal modes [2, 3, 4] to internal modes [19, 17, 21]. Essentially, the encoder maps and signals modes 19 with intra mode and mode 2 with intra code, and then the decoder demaps and displays mode 2 with intra mode 19. Moreover, this simple mapping reduces the number of reduction operations for mode signaling. non-MPM versus signaling non-MPM modes using a list and specifying an index in the list. In a special case, if the "received non-MPM modes" and the "internal codeword modes" with the smallest codeword have overlap, then it is guaranteed that the common internal mode for both lists is displayed together. For example, if "internal codeword modes" are [2, 3, 4] and the list of "received non-MPM modes" is [2, 4, 17], then internal mode 2 is mapped to internal mode 2, mode 3 is mapped to mode 17 and mode 4 is mapped to mode 4.

In another example, several solutions are proposed to populate the first three modes of the list of remaining modes.

First, using modes from a predefined list of default modes, which includes {planar mode (PLANAR_IDX), DC mode (DC_IDX), vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 (2), vertical diagonal mode (VDIA_IDX), diagonal mode (DIA_IDX)} (terms in brackets indicate the corresponding terms in Fig. 6, more details on Fig. 6 are given below);

Secondly, with the help of shifting angular modes, which are already present in the MPM list. Here, the offset can be +/- N, where N is a possible integer value whose value is {1, 2, 3, 4}. Offsets can only be added to the first two angle modes from the MPM list.

Third, the internal modes of non-adjacent neighbors can also be used to populate the three modes. As shown in FIG. 7, internal neighbor modes of the second layer may be used.

Fourth, as shown in FIG. 6, the first step selects a given mode from the MPM list and checks if it is "near" one of the following mode categories {DC_IDX, HOR_IDX, DIA_IDX, VER_IDX, VDIA_IDX}. In the second step, the mode categories are then "sorted" based on the "most" modes that are close to it. In the third step, a list of the remaining modes is formed by inserting the modes that are next to the category of winning modes from step 2.

In FIG. 6 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. 6 refers to index 2, and the index numbering is incremented until index 66 is the uppermost right corner mode in FIG. 6.

The following is a description of a network device suitable for implementing the disclosed embodiments as described herein. The network device contains input ports and blocks (Rx) of the receiver for receiving data; processor, logical unit or central processing unit (CPU) for data processing; blocks 1340 transmitter (Tx) and output ports for data transmission; and memory for data storage. The network device may also include optical-electrical (OE) components and electrical-optical (EO) components connected to input ports, receiver units, transmitter units, and output ports for output or input of optical or electrical signals.

The processor is implemented by hardware and software. A processor 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 communicates with input ports, receiver blocks, transmitter blocks, output ports, and memory. The processor contains an encoding module. The encoding module implements the disclosed embodiments described above. For example, the encoding module implements, processes, prepares, or provides various network functions. Thus, the use of the encoding module provides a significant improvement in the functionality of the network device and allows the transformation of the network device into another state. Alternatively, the encoding module is implemented as instructions stored in memory and executed by the processor.

Memory consists of one or more disks, tape drives, and solid state drives and can be used as an overflow storage device, for storing programs when such programs are selected for execution, and for storing instructions and data that are read during program execution. The memory 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).

Fig. 10 is a block diagram of an apparatus 1500 that can be used to implement various embodiments. Device 1500 may be source device 12 as shown in FIG. 1 or video encoder 20 as shown in FIG. 2 or destination device 14 as shown in FIG. 1 or video decoder 30 as shown in FIG. 3. Additionally, device 1500 may include one or more of the elements described. In some embodiments, device 1500 is equipped with one or more input/output devices, such as a speaker, microphone, mouse, touch screen, keyboard, keypad, printer, display, and the like. Device 1500 may include one or more central processing units (CPUs) 1510, memory 1520, mass storage device 1530, video adapter 1540, and an 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 be any type of system memory, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM memory (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. The mass storage device 1530 includes any type of storage device that stores data, programs, and other information and makes the data, programs, and other information available 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 input and output devices to device 1500. For example, device 1500 may provide a SQL command interface to clients. As shown, examples of input and output devices include a display 1590 connected to a video adapter 1540 and any combination of a mouse/keyboard/printer 1570 connected to an input/output interface 1560. Other devices may be connected to device 1500, 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 1500 also includes one or more network interfaces 1550, which include wired links such as an Ethernet cable and the like, and/or wireless links to access points or one or more networks 1580. Network interface 1550 allows the device 1500 to communicate with remote devices over the networks 1580. For example, the network interface 1550 may provide communication with a database. In an embodiment, the device 1500 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 methods of overlay in image processing).

Embodiments comprise, for example, a device for determining a received intra prediction mode based on a most likely mode (MPM) list and a remaining mode list having a first part and a second part, wherein the received intra prediction mode is one of a plurality of intra prediction modes comprising a plurality angular intra prediction modes for predicting sample values of the current image block, in which the device contains a processing circuit configured to: generate the first part of the list of remaining modes by adding one or more angular intra prediction modes determined based on the list of most likely modes, so that one or a plurality of angular intra prediction modes of the first part of the remaining mode list are close to the corresponding angular intra prediction mode of the most likely mode list; and determine the received intra prediction mode if the received intra prediction mode is part of the first part of the list of remaining modes, using fewer bits, for example, to encode or decode the received intra prediction mode than if the received intra prediction mode is part of the second part of the list the remaining modes.

In an example, in which the processing circuit is configured to generate a first part of the remaining mode list by: ranking a plurality of angular intra prediction mode categories according to the number and/or direction of the most likely mode list of angular intra prediction modes falling under each angular intra prediction mode category; and generating a first part of the remaining mode list by adding one or more angular intra prediction modes from the highest ranked angular intra prediction mode category in the remaining mode list.

The embodiments contain, for example, 5 categories of the angular intra prediction mode, namely, 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 mode of the angular intra prediction mode of the list of most likely modes falling into each category of the angular intra prediction mode, for example, corresponds to the association of each of the angular intra prediction modes from the list of most likely modes with the angular intra prediction mode category closest to the corresponding angular intra prediction mode of the list of most likely modes.

In one example, the processing circuit is further configured to complete the first part of the list of remaining modes by repeating with the second highest category of the angular intra prediction mode.

In the example, each intra prediction mode is identified by an intra prediction mode index, and the processing circuit is configured to determine a plurality of angle intra prediction mode categories based on respective angle intra prediction modes associated with a horizontal direction, a vertical direction, and one or more diagonal directions.

In the example, each intra prediction mode is identified by an intra prediction mode index, and the processing circuit is configured to generate a first part of the remaining mode list by adding one or more angular intra prediction modes to the first part of the remaining mode list whose corresponding intra prediction mode index has an offset of +1 , -1, +2, -2, +3, -3, +4, or -4 with respect to the intra prediction mode index of the angular intra prediction mode of the most likely mode list.

In one example, each list element of the most likely mode list is identified by a most likely mode index, and the processing circuit is configured to generate a first part of the remaining mode list by adding one or more angular intra prediction modes to the first part of the remaining mode list whose corresponding intra mode index prediction has an offset of +1, -1, +2, -2, +3, -3, +4, or -4 relative to the intra prediction mode index of the angular intra prediction mode of the most likely mode list.

In the example, the processing circuit is configured to generate the first part of the remaining mode list by adding one or more angular intra prediction modes to the first part of the remaining mode list based on the processing cycle, starting at an offset of +1 with respect to the intra prediction mode index of the list angular intra prediction mode. most likely modes, which increases during each round of the processing cycle, or with an offset of -1 with respect to the intra-prediction mode index of the angular intra-prediction mode of the list of most likely modes, which decreases during each round of the processing cycle.

In the example, the processing circuit is configured to repeat the processing cycle for the angular intra prediction mode of the most likely mode list having the smallest most likely mode index more often than the processing cycle for the angular intra prediction mode of the most likely mode list with the largest most likely mode index.

In the example, the processing circuit is configured to generate the first part of the remaining mode list by adding one or more angular intra prediction modes to the first part of the remaining mode list whose corresponding intra prediction mode index has an offset of +2, -2, +4, -4, + 6, -6, +8, or -8 with respect to the intra prediction mode index of the angular intra prediction mode of the most likely mode list.

In an example, in which the processing circuit is further configured to generate a second part of the remaining mode list by adding those intra prediction modes from the plurality of intra prediction modes to the second part of the remaining mode list that are not part of the most likely mode list and the first part of the remaining mode list.

In the example, the processing circuit is further configured to predict sample values of the current image block using the received intra prediction mode and to provide the predicted image block (105).

In one example, the device is an encoding device, and wherein the processing circuit is further configured to: encode the current image block based on the predicted image block and the received intra prediction mode.

In the example, the processing circuit is further configured to signal a truncated binary code for the intra prediction mode of the current image block if the intra prediction mode belongs to the rest modes list.

In one example, the device is a decoding device, and wherein the processing circuitry is further configured to decode the current image block based on the predicted image block and the received intra prediction mode.

In an example, in which the processing circuit is further configured to analyze the truncated binary code to determine the intra prediction mode of the current image block, if the intra prediction mode belongs to the list of remaining modes.

An example provides a method for determining a received intra prediction mode based on a list of most likely modes and a list of remaining modes having first and second parts, wherein the received intra prediction mode is one of a plurality of intra prediction modes comprising a plurality of angular intra prediction modes for predicting sample values. of the current image block, in which the method comprises: generating the first part of the list of remaining modes by adding one or more angular intra prediction modes determined based on the list of most likely modes, so that one or more angular intra prediction modes of the first part of the list of remaining modes are close to the corresponding an angular intra prediction mode from the list of most likely modes; and determining the received intra prediction mode if the received intra prediction mode is part of the first part of the remaining mode list, using fewer bits, for example, to encode or decode the received intra prediction mode than if the received intra prediction mode is part of the second part. list of remaining modes.

By way of example, a computer program product is provided containing program code for executing the above examples when executed on a computer or processor.

In the example, the processing circuit is further configured to determine the first part of the list of remaining modes from a predetermined list of default modes, containing or consisting of planar mode (PLANAR_IDX), DC mode (DC_IDX), vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 (2), vertical diagonal mode (VDIA_IDX) and diagonal mode (DIA_IDX).

In one example, the processing circuitry is further configured to determine the first part of the list of remaining modes by adding second level neighbor intra prediction modes of the current image block.

In one example, at both the encoder and decoder, the intra mode is signaled using truncated binarization for non-MPM intra modes.

In the example, since truncated binarization can be used to encode 61 non-MPM modes, the first three modes would require 5 bits to be transmitted, and hence the first three modes in the non-MPM mode list are generated based on the internal modes that are already included in the MPM list.

In an example where the first three modes in the list of non-MPM modes are signaled by a simple codeword mapping, in which the mapping in the encoder is defined as the stage that maps an intra mode codeword known to consume fewer bits with "different intrinsic mode" , which is known to consume more bits and at the same time is more likely. In the decoder, inverse mapping is defined as a step that maps the intra mode that has been parsed from the bitstream to a "different intra mode" which is then used as the actual intra prediction mode for the current image block.

In one example, a method for decoding video data is provided, comprising: receiving encoded image block data of an encoding block; decoding the encoded data to identify an intra prediction mode from the plurality of intra prediction modes for the image block, the plurality of intra prediction modes comprises a set of most probable modes, MPM, a first set of intra prediction modes, and a second set of intra prediction modes, in which one mode in the first set of intra prediction modes prediction is encoded using N bits, one 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, decoding the encoded data to identify an intra prediction mode from a plurality of intra prediction modes for a picture block, comprising: decoding the encoded data to obtain an indication indicating whether the intra prediction mode for the image block is in the MPM set or not; if an indication indicating the intra prediction mode for the image block is not in the MPM set, obtaining an intra prediction mode codeword for the image block, an intra prediction mode codeword corresponding to the original intra prediction mode; if the intra prediction mode codeword for the image block is encoded using N bits, mapping the original intra prediction mode to obtain a mapped intra prediction mode using the mapped intra prediction mode as the identified intra prediction mode for the image block; or, if the intra prediction mode codeword for the image block is encoded using M bits, use the original intra prediction mode as the identified intra prediction mode for the image block.

In an example, if an intra prediction mode codeword for an image block is encoded using N bits, the value of the intra prediction mode codeword for the image block is less than any of the plurality of values corresponding to the second set of intra prediction modes.

In an example, the intra prediction source mode mapping to obtain the intra prediction mapped mode comprises: intra prediction source mode mapping according to the MPM set to obtain the intra prediction mapped mode.

In an example, the initial intra prediction mode mapping according to the MPM set 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; displaying the original intra prediction mode according to the highest category of the intra prediction mode.

In one example, mapping an initial intra prediction mode according to the MPM set comprises: generating an initial intra prediction mode set according to adding an offset to a set of values corresponding to the MPM set; classifying the set of MPMs to obtain the category of the intra prediction mode with the highest rank; displaying the original intra prediction mode according to the category of the highest ranking intra prediction mode and the original 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 MPM set.

In one example, an intra prediction source mode mapping to obtain a mapped intra prediction mode comprises: an intra prediction source mode mapping according to a predetermined default mode list comprising or consisting of planar mode (PLANAR_IDX), 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) to obtain the mapped intra prediction mode.

In some examples, additional aspects of the present invention are summarized as follows:

The present invention provides a method for decoding video data, comprising: decoding encoded data of a picture block to obtain an intra prediction mode from a plurality of intra prediction modes for the picture block, the plurality of intra prediction modes for the picture block comprising a set of most likely modes, MPMs, and a set of non-MPMs, in wherein the non-MPM set comprises a first intra prediction mode set and a second intra prediction mode set, wherein one mode in the first intra prediction mode set is encoded using N bits, one mode in the second intra prediction mode set is encoded using M bits, N and M are positive integers, N less than M, in which decoding the encoded data of the image block to obtain an intra prediction mode from a plurality of intra prediction modes for the image block, comprising: decoding the encoded data for obtaining an indication indicating whether the intra prediction mode for the image block is in the MPM set or not; if an indication indicating the intra prediction mode for the image block is not included in the set of MPMs, 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- MPM; decoding the encoded data to obtain an intra prediction mode codeword for the image block; obtaining an intra prediction mode for the image block according to the display ratio and the intra prediction mode codeword.

In an embodiment, a mapping relation is generated according to a set of MPMs.

In an embodiment, a display relationship is generated according to a predetermined default mode list, comprising or consisting of Planar Mode (PLANAR_IDX), DC Mode (DC_IDX), Vertical Mode (VER_IDX), Horizontal Mode (HOR_IDX), Inner Mode 2(2) , vertical diagonal mode (VDIA_IDX) and diagonal mode (DIA_IDX).

In an embodiment, 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-MPM set, comprising: ranking a plurality of intra prediction mode categories according to the number and/ or the direction of the intra prediction modes in the set of MPMs falling into each category of the intra prediction mode; generating a display relation according to the category of the intra prediction mode with the highest rank.

In an embodiment, generating a mapping relationship between an intra prediction mode in the first intra prediction mode set and an intra prediction mode in the second intra prediction mode set, comprising: generating an initial intra prediction mode set according to adding an offset of a set of values corresponding to the 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 original intra prediction mode set.

In an embodiment, 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.

In an embodiment, 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-MPM set, comprising: generating a first set of values according to values from the modes predictions in the MPM set, one value in the first value set is the smallest prediction mode value in the non-MPM set; generating a second set of values according to adding an offset to a value of at least one prediction mode in the set of MPMs; generating a display relation according to the first set of values and the second set of values.

In an embodiment, 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-MPM set, comprising: generating a first set of values according to values from the prediction modes in set of MPMs, one value in the first set of values is the smallest value of the prediction mode in the set of non-MPMs; generating a second set of values in accordance with adding an offset to a value of at least one angle prediction mode in the set of MPMs; generating a display relationship according to the first set of values and the second set of values.

In an embodiment, the number of prediction modes in the intra prediction mode set for a picture block is 67, the number of prediction modes in the MPM set is 6, the number of prediction modes in the first intra prediction mode set in the non-MPM set is 3, and the number of prediction modes in the second set is intra prediction modes in the non-MPM set is 58, wherein 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-MPM set comprises: deriving the lowest three values of the three prediction modes in the non-MPM set according to the values of the prediction modes in the set of MPMs; obtaining two values of two angle prediction modes in the set of MPMs, adding an offset to the two values to obtain offset values; obtaining a second set of values according to the values of the prediction modes in the set of MPMs and the offset values; generating a display relationship according to the first set of values and the second set of values.

In an embodiment, generating a mapping relationship between at least one intra prediction mode in a first intra prediction mode set and at least one intra prediction mode in a non-MPM set comprises: generating a first set of values according to values from the prediction modes in set of MPMs, one value in the first set of values is the smallest value of the prediction mode in the set of non-MPMs; generating a second set of values according to a predefined default mode list comprising or consisting of vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 (2), vertical diagonal mode (VDIA_IDX), and diagonal mode (DIA_IDX); generating a display relationship according to the first set of values and the second set of values.

In an embodiment, generating a mapping relationship between at least one intra prediction mode in a first intra prediction mode set and at least one intra prediction mode in a non-MPM set comprises: generating a first set of values according to values from the prediction modes in set of MPMs, one value in the first set of values is the smallest value of the prediction mode in the set of non-MPMs; generating a second set of values according to a predefined list of default modes, containing or consisting of planar mode (PLANAR_IDX), DC mode (DC_IDX), vertical mode (VER_IDX), horizontal mode (HOR_IDX), internal mode 2 ( 2), vertical - diagonal mode (VDIA_IDX) and diagonal mode (DIA_IDX); generating a display relationship according to the first set of values and the second set of values.

In an embodiment, the intra prediction mode codeword is encoded using 5 bits, and the intra prediction mode codeword is one of 00000, 00001, or 00010.

In an embodiment, one of the at least one intra prediction mode in the first intra prediction mode set corresponds to one of the at least one intra prediction mode in the non-MPM set.

In addition, a decoder is provided, comprising a processing circuit configured to perform any of the above methods.

Additionally, a computer program product is provided that contains program code for performing any of the above methods.

Additionally, a decoder is provided for decoding video data, comprising: one or more processors; and a persistent computer-readable storage medium coupled to the processors and storing programs for execution by the processors, wherein the programs, when executed by the processors, configure the decoder to execute the method of any one of claims 1-13.

The present invention provides a method for listing the most likely mode, MPM, 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 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.

In an embodiment, when the left block prediction mode is not an intra prediction mode, the left block of the current coding block is not available.

In an embodiment, when the current coding block is the coding block located on the leftmost side of the frame, the left block of the current coding block is not available.

In an embodiment, parallel processing is supported and the current coding block is the coding block located at the leftmost side of the tile, the left block of the current coding block is not available.

In an embodiment, parallel processing is not supported and the current coding block is the coding block located on the leftmost side of the tile, but not on the lesser left side of the frame, the left block of the current coding block is available.

In an embodiment, parallel processing is supported and the current coding block is a coding block located at the leftmost side of the segment, the left block of the current coding block is not available.

In an embodiment, parallel processing is not supported and the current coding block is a coding block located on the leftmost side of the segment, but not on the leftmost side of the frame, the left block of the current coding block is available.

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

In an embodiment, when the current coding block is the coding block located at the topmost side of the frame, the top block of the current coding block is not available.

In an embodiment, parallel processing is supported and the current coding block is the coding block located at the topmost side of the tile, the top block of the current coding block is not available.

In an embodiment, 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 an embodiment, parallel processing is supported and the current coding block is a coding block located at the topmost side of the segment, the top block of the current coding block is not available.

In an embodiment, parallel processing is not supported and the current coding block is the coding block located on the topmost side of the segment, but not on the topmost side of the frame, the topmost block of the current coding block is available.

In an embodiment, when the size of the linear buffer is limited and the current coding unit is a coding unit located at the topmost side of the current CTU, the top block of the current coding unit is not available.

In an embodiment, 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 a new prediction mode in the MPM list.

In an embodiment, the offset is -1.

In an embodiment, the offset is 1.

In an embodiment, 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 offset-high prediction mode, if the offset-top prediction mode is not in the MPM list, adding bias-top prediction mode to the MPM list.

In an embodiment, the offset is -1.

In an embodiment, the offset is 1.

In one embodiment, the method further comprises:

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.

In an embodiment, the method further comprises a corner mode candidate list comprising or consisting of: vertical mode (VER_IDX), horizontal mode (HOR_IDX), inner 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.

In an embodiment, the compilation of the MPM list begins with the step of determining if the left block of the current coding block is available, for example, based on an empty MPM list.

In an embodiment, the method further comprises: 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 original MPM list, if the left block is available, not inserting another block's intra prediction mode into the original MPM list.

In an embodiment, the method further comprises: if the top block of the current coding block is not available and another block is available in the general specified up direction (e.g., AR or AL in FIG. 5), inserting the intra prediction mode of the other block into the original MPM list if the top block is available , not inserting another block's intra prediction mode into the original MPM list.

In an embodiment, the method further comprises: adding vertical mode (VER_IDX), horizontal mode (HOR_IDX), inner mode 2 (2), vertical diagonal mode (VDIA_IDX) or diagonal mode (DIA_IDX) to the source MPM list if they are not already in the source MPM list.

In an embodiment, the method further comprises: if both the left and the top block of the current coding block are not angular, then one more neighboring block is additionally checked (eg, 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;

The present invention further provides an encoder containing a processing circuit for performing any of the above methods.

The present invention further provides a decoder containing a processing circuit for performing any of the above methods.

The present invention further provides a computer program product containing program code for performing any of the above methods.

The present invention further provides 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 any of the above methods.

The present invention further provides an encoder 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 encoder to perform any of the above methods.

Implementations of the subject matter and operations described in this invention may be implemented in digital electronic circuits, or in computer software, firmware, or hardware incorporating the structures disclosed in this invention and their structural equivalents, or in combinations of one or several of them. Implementations of the subject matter described in this invention 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 execution by data processing. A computer storage medium, such as a computer-readable medium, may be or contained in a computer-readable storage device, a computer-readable storage, an array, or a random-access or sequential-access memory 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 invention may be implemented as a host 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 "in the cloud" can be used interchangeably, if necessary, without departing from the scope of the present invention. Cloud services can 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 scheme may 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 scheme.

A computer program (also known as a program, software, software application, script, or code) may be written in any programming language, including compiled or interpreted languages, declarative or procedural languages, and may be deployed in any form, including 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 part 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 several coordinated 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 invention 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 logic flows can also be executed, 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 ROM or Random Access Memory, or both. The essential 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 operatively connected to receive data from or transmit data to one or more mass storage devices for data storage, such as magnetic, magneto-optical disks or optical disks. However, a 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 (such as a flash drive with a universal serial bus (USB)) and many others. 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 this 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 descriptions of features specific to particular implementations of particular implementations. Some of the features that are described in this entity invention in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various functions 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 initially claimed as such, in some cases one or more features of the claimed combination may be excluded from the combination, and the claimed combination may be a subcombination or a variation of the subcombination.

Similarly, although the operations are shown in the drawings in a specific 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 illustrated operations be performed to achieve the desired results. 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 particular order shown or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing may be useful.

Although the present invention presents several embodiments, it should be understood that the disclosed systems and methods can be embodied in many other specific forms. 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 technologies described and illustrated in various embodiments as separate or discrete 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 connected or directly connected or interacting with each other may be indirectly connected or interact electrically, mechanically or otherwise through some interface, device or intermediate component.

Abbreviations definitions and glossary

CTU/CTB - Coding Tree Block

CU/CB - Coding Block

PU/PB - Prediction Block

TU/TB - Transform Block

HEVC - High Efficiency Video Coding.

Claims (21)

1. A method for compiling a list of the most probable mode (MPM) for the prediction process corresponding to a video block, 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, in which, when parallel processing is supported and the current coding block is the coding block located in the leftmost side segment or tile, the left block of the current coding block is not available; 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; adding an offset to the left block intra prediction mode to obtain a new prediction mode if the left block of the current coding block is available and the left block intra prediction mode is an angular mode; and adding a new prediction mode to the MPM list if the new prediction mode is not in the MPM list; or adding an offset to the upper block intra prediction mode to obtain the offset upper block prediction mode if the upper block of the current coding block is available and the upper block intra prediction mode is an angular mode; and adding the offset top block prediction mode to the MPM list if the offset top block prediction mode is not in the MPM list. 2. The method of claim 1, wherein the offset is -1 or +1. 3. The method according to claim 1 or 2, further comprising if the planar mode is not in the MPM list, adding the planar mode to the MPM list; and if the DC mode is not in the MPM list, add the DC mode to the MPM list. 4. The method according to any one of paragraphs. 1-3, in which, when the left block prediction mode is not intra prediction mode, the left block of the current coding block is unavailable. 5. The method according to any one of paragraphs. 1-4, wherein when the current coding block is the coding block located at the leftmost side of the frame, the left block of the current coding block is unavailable. 6. The method according to any one of paragraphs. 1-5, wherein when parallel processing is not supported and the current coding block is a coding block located on the leftmost side of a segment or tile, but not on the leftmost side of a frame, the left block of the current coding block is available. 7. The method according to any one of paragraphs. 1-6, in which, when the upper block prediction mode is not an intra prediction mode, the upper block of the current coding block is unavailable. 8. The method according to any one of paragraphs. 1-7, in which, when the current coding block is the coding block located at the topmost side of the frame, the top block of the current coding block is unavailable. 9. The method according to any one of paragraphs. 1-8, in which, when parallel processing is supported and the current coding block is the coding block located on the topmost side of the segment or tile, the top block of the current coding block is not available. 10. The method according to any one of paragraphs. 1-9, wherein when parallel processing is not supported and the current coding block is a coding block located on the topmost side of a segment or tile but not on the topmost side of a frame, the topmost block of the current coding block is available. 11. The method according to any one of paragraphs. 1-10, in which, when the size of the linear buffer is limited and the current coding unit is the coding unit located on the uppermost side of the current coding tree block, CTU, the upper block of the current coding unit is not available. 12. An encoder containing a processing circuit for performing the method according to any one of paragraphs. 1-11. 13. A decoder containing a processing circuit for performing the method according to any one of paragraphs. 1-11. 14. A computer-readable medium containing a program code tool that, when loaded into a computer, controls it to perform the method according to any one of paragraphs. 1-11.

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