RU2784004C2 - Derivation of internal prediction mode based on neighboring blocks - Google Patents

Abstract

FIELD: image encoding/decoding.

SUBSTANCE: invention relates to the field of a technology of image and/or video encoding and decoding and, in particular, to a method and equipment for an internal prediction. A list of the most probable modes (MPM) for an internal prediction is built. At the same time, list building contains: determination, whether a block left from the current encoding block is available; determination, whether a block above the current encoding block is available; use of a planar mode, DC mode, a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index), an internal prediction mode corresponding to the specified vertical mode with a shift of -4, an internal prediction mode corresponding to the specified vertical mode with a shift of 4 to obtain an index value for an internal prediction mode for the current encoding block, if one of conditions is met.

EFFECT: increase in the encoding efficiency.

17 cl, 10 dwg, 2 tbl

Description

The technical field to which the invention belongs

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

State of the art

Digital video has become widely used since the introduction of DVDs. Before being transmitted, the video is encoded and then transmitted using a transmission medium. The viewer receives this video and uses the viewing device to decode and present the video on a display. Video quality has improved over the years, for example due to higher resolutions, color depths and frame rates. This has led to increased volumes of data streams, which today are usually transported through the Internet and through mobile networks.

Higher resolution video, however, usually requires more bandwidth because the video contains more information. To reduce bandwidth requirements, video coding standards using video compression have been developed and implemented. When video is encoded, the bandwidth requirements (or corresponding memory requirements in the case of memory and information storage) are reduced. Often this decline comes at the expense of quality. Thus, video coding standards strive to strike a balance between bandwidth requirements and quality.

High Efficiency Video Coding (HEVC) is an example of a video coding standard that is widely known to those skilled in the art. The HEVC coding standard splits the coding unit (CU) into prediction units (PU) or transform units (TU). Versatile Video Coding (VVC), the next generation standard, is the latest collaborative video project of the Video Coding Experts Group (VCEG) in the telecommunications standardization sector of the International Union for telecommunications (ITU-T) and the International Standards Organization/International Electrotechnical Commission (ISO/IEC) Moving Picture Experts Group (MPEG), which work together in a partnership known as the Joint Video Research Group (Joint Video). Exploration Team (JVET))). The VVC coding standard is also called the Next Generation Video Coding (ITU-T H.266/Next Generation Video Coding (NGVC)). The VVC coding standard is supposed to eliminate the concept of multiple types of splits, i.e. separating the concepts of CUs, PUs, and TUs, except to the extent necessary for CUs that are too large for the maximum transform length, and maintain more flexibility for CU partitioning forms.

How these coding units (CUs) (also referred to as blocks) are processed depends on their size, internal layout, and the coding mode specified by the encoder. The coding modes can be classified into two groups according to the type of prediction: intra prediction and inter prediction modes. The intra prediction modes use samples from the same picture (also referred to here as a frame or image) to generate reference samples to calculate predictive values for the samples of the block that is currently being reconstructed. Intra prediction is also called spatial prediction. Mutual prediction modes are for temporal prediction and use reference samples from previous or next pictures to predict a block of the current picture.

The ITU-T VCEG (Q6/16) and ISO/IEC MPEG (JTC 1/SC 29/WG 11) Expert Groups are currently investigating the potential need for standardization of future video coding technologies that would greatly outperform video compression capabilities. capabilities of the current HEVC coding standard (including its current and near future extensions for screen content encoding and high dynamic range encoding). These groups work together on research in this area as part of a collaborative activity in a group called the Joint Video Experts Group (JVET) to evaluate compression technology options proposed by the group's expert members in the field.

The Versatile Test Model (VTM) standard uses 35 intra prediction modes, while the Benchmark Set (BMS) standard uses 67 intra prediction modes.

The intra prediction mode coding scheme described today in the BMS standard is considered complex, and the disadvantage of the non-selection mode set is that the index list always remains constant rather than adapting based on the properties of the current block (for example, for intra prediction modes with respect to neighboring blocks with it).

Brief summary of the invention

Apparatus and method for internal prediction are proposed. This apparatus and method uses a mapping procedure to simplify the calculation procedure for intra prediction in order to improve coding efficiency. The scope of protection is determined by the Claims.

Brief description of the drawings

The following options 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 configured to implement embodiments of the present invention;

fig. 2 is a block diagram showing an example of a video encoder configured to implement embodiments of the present invention;

fig. 3 is a block diagram showing an example of the structure of a video decoder configured to implement embodiments of the present invention;

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

fig. 5 shows a simplified diagram illustrating neighboring blocks for deriving MPM modes;

fig. 6 shows a simplified diagram illustrating second-tier adjacent intra prediction modes used to determine the first three modes in the remaining mode list;

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

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

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

fig. 10 shows a block diagram of the apparatus.

Detailed description

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

For example, it is understood that the invention, together with the described method, may also remain valid for the corresponding device or system configured to implement this method, and vice versa. For example, when describing a specific method step, the corresponding device may contain a module for implementing the described method step, even if such a module is not explicitly described here or illustrated in the drawings. Further, it is to be understood that features of the various exemplary aspects described herein may be combined with one another unless specifically indicated to the contrary.

The term "video coding" refers to the processing of a sequence of pictures that make up a video or video sequence. The terms "picture", "picture" or "frame" in the field of video coding, as well as in the present description, can be/are used interchangeably. Each image is usually divided into many blocks that do not overlap one another. Image encoding/decoding is usually done at the block level, where, for example, inter prediction or intra prediction is used to generate a predictive block in order to subtract this predictive block from the current block (block currently being processed/to be processed) to obtain a residual block that it is then transformed and quantized to reduce the amount of data to be transmitted (compressed), while at the decoder side, the encoded/compressed block is reversed to reconstruct the block for presentation.

In FIG. 1 is a conceptual or simplified block diagram illustrating an example of an encoding system 10, such as a video encoding system 10, that may use the technology of the present application (of the present invention). Encoder 20 (eg, video encoder 20) and decoder 30 (eg, video decoder 30) in video encoding system 10 represent examples of devices that can be configured to implement technologies in accordance with the various examples described herein. As shown in FIG. 1, encoding system 10 comprises a source device 12 configured to provide encoded data 13, such as an encoded image 13, to, for example, a destination device 14 to decode the encoded data 13.

Source device 12 includes an encoder 20 and may additionally, i. e. optionally comprise an image source 16 , a preprocessing module 18 , such as an image preprocessing module 18 , and a communication interface or communication module 22 .

Image source 16 may comprise or be some type of image capturing device, such as for capturing an image of the real world, and/or some type of image or comment generation device (for encoding content present on the screen, any text on that screen is also considered to be part of the picture or image to be encoded), such as a computer graphics processor for generating a computer animation image, and/or some type of device for capturing and/or generating an image of the real world, an image of a computer animations (e.g., screen content, virtual reality (VR) images, and/or any combination of such images (e.g., augmented reality (AR) images).

An image (digital) is or can be viewed as a two-dimensional array or matrix of samples, each of which has some intensity value. A sample in an array can also be called a pixel (short for image element) or a raster element (pel). The number of samples in the horizontal and vertical direction (or along the respective axes) determines the size and/or resolution (resolution) of the image. Three color components are usually used to represent a color, i.e. the image may be represented or may contain three arrays of samples. In RBG format or color space, an image contains corresponding arrays of red (red), green (green), and blue (blue) samples. However, in video coding, each pixel is typically represented in a luma/chrominance format or color space, such as YCbCr, which contains a luminance component, denoted by the letter Y (sometimes the letter L is also used instead) and two chrominance components, denoted by Cb and Cr . The luminance (or abbreviated "luma") Y component represents the brightness or intensity level of the green color (such as in a grayscale (black and white) image), while the two chroma (or abbreviated chroma) components Cb and Cr represent the chromaticity (chromaticity) components. or color information. Accordingly, the YCbCr format image contains an array of luminance samples formed from the values of the luminance samples (Y) and two arrays of chrominance samples formed from the values of the chrominance samples (Cb and Cr). Images in RGB format can be converted or converted to YCbCr format and vice versa, this process is also known as color coordinate conversions or conversion. When an image is monochrome (black and white), such an image can only contain an array of luminance samples.

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

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

The pre-processing module 18 is configured to receive (raw) image data 17 and to perform pre-processing of this image data 17 to obtain a pre-processed image 19 or pre-processed image data 19. The pre-processing performed by the pre-processing module 18 may, for example, include format cropping, color format conversion (eg, from RGB to YCbCr), color correction, or noise reduction. It should be understood that the module 18 pre-processing may be an optional component, applied when necessary (as an option).

An encoder 20 (eg, video encoder 20) is configured to receive pre-processed image data 19 and generate encoded image data 21 (further details will be described below, for example, based on FIG. 2).

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

Destination device 14 includes a decoder 30 (eg, video decoder 30) and may additionally, i.e. optionally comprise a communication interface or communication module 28, a post-processing module 32 and a display device 34.

Communication interface 28 at destination device 14 is configured to receive encoded image data 21 or encoded data 13, for example directly from source device 12 or from some other source such as a storage device, such as a storage device for encoded image data.

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

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

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

Both interfaces, 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. 1A, where this arrow points from the source device 12 to the destination device 14, or as bidirectional communication interfaces and can be configured, for example, to send and receive messages, for example, to establish a connection, to handshake and exchange any other information regarding the communication channel and/or data transmission, for example, the transmission of encoded image data.

The decoder 30 is configured to receive encoded image data 21 and generate decoded image data 31 or decoded image 31 (further details will be described below, for example, based on Fig. 3).

The post processor 32 in the destination device 14 is configured to post-process the decoded image data 31 (also referred to as reconstructed image data), such as the decoded image 31, to obtain post-processed image data 33, such as the post-processed image 33. The post-processing performed by the post-processing module 32 may contain, for example, color format conversion (for example, from YCbCr format to RGB format), color correction, format cropping or resampling, or some other processing, for example, to prepare the decoded image data 31 for presentation on a display, for example, a display device 34.

Display device 34 at destination device 14 is configured to receive post-processed image data 33 for the purpose of presenting an image on a display to, for example, a user or viewer. The display device 34 may be or may include some type of display for presenting the rendered image, such as an integrated or external display or monitor. Such a display may be, for example, a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro light-emitting diode (LED) display, a silicon liquid crystal display ( liquid crystal on silicon (LCoS), digital light processor (DLP), or some other type of display.

Although in FIG. 1, source device 12 and destination device 14 are shown as separate devices, device variants may contain both devices or functionality of both devices, namely source device 12 or related functionality and destination device 14 or related functionality. In such embodiments, source device 12 or related functionality and destination device 14 or related functionality may be implemented using the same hardware and/or software, or different hardware and/or software, or some combination. listed components.

As will be appreciated by those skilled in the art based on the present disclosure, the existence and (exact) breakdown of the functionality of the various modules, or functionality within source device 12 and/or destination device 14, as shown in FIG. 1 may vary depending on the actual device and application.

Each device, encoder 20 (e.g., video encoder 20) and decoder 30 (e.g., video decoder 30), can be implemented as any one of a variety of suitable circuits, such as one or more devices from the list − microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic devices, hardware, or any or a combination of the listed components. When these technologies are implemented in part in software, a 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 implement the technology of the present invention. Any of the above (including hardware, software, a combination of hardware and software, and the like) may be considered one or more processors. Each of video encoder 20 and video decoder 30 may be included in one or more encoders or decoders, where any such device may be integrated as part of a combined encoder/decoder (CODEC) in corresponding device.

In FIG. 2 shows a simplified/conceptual block diagram of an example of a video encoder 20 configured to implement the technology of this application. In the example shown in FIG. 2, the video encoder 20 includes a residual calculation module 204, a transform processor module 206, a quantizer module 208, an inverse quantizer module 210, and an inverse transform processor module 212, a reconstruction module 214, a buffer 216, a loop filter module 220, a decoded image buffer 230 (decoded picture buffer (DPB)), prediction processor module 260, and entropy encoding module 270. Prediction processor module 260 may include an inter prediction module 244, an intra prediction module 254, and a mode selection module 262. The inter prediction module 244 may include a motion estimation module and a motion compensation module (not shown). Video encoder 20, as 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 unit 204, the transform processor unit 206, the quantization unit 208, the prediction processor unit 260, and the entropy encoding unit 270 form a forward signal path in the encoder 20, while, for example, the inverse quantization unit 210, the processor unit 212 inverse transform, reconstruction module 214, buffer 216, loop filter 220, decoded picture buffer (DPB) 230 230, prediction processor module 260 form a signal return path in the encoder, where the signal return path in the encoder corresponds to the signal transmission path in the decoder. device (see decoder 30 shown in FIG. 3).

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

The prediction processor module 260, also referred to here as the block prediction processor module 260, is configured to receive or obtain a block 203 (the current block 203 from the current picture 201) and reconstructed picture data, such as reference samples of the same (current) picture from the buffer 216 and /or reference picture data 231 from one or more previously decoded pictures from decoded picture buffer 230, and for processing such data for prediction purposes, i. e. generating a predicted block 265, which may be an inter prediction block 245 or an intra prediction block 255.

Mode select module 262 may be configured to select a prediction mode (e.g., intra or inter prediction mode) and/or an appropriate predictive block 245 or 255 for use as predictor 265 to calculate residual block 205 and reconstruct reconstructed block 215.

Variants of mode select module 262 may be configured to select the prediction mode (eg, from a set of modes supported by prediction processor module 260) that provides the best match and, in other words, minimum residual (minimum residual means better compression for transmission or storage), or minimum signaling overhead (lowest signaling overhead means better compression for transmission or storage), or a mode that takes into account or balances both residue and overhead. The mode selector 262 may be configured to determine a prediction mode based on rate distortion optimization (RDO) optimization, i. selecting a prediction mode that provides the least optimization of the rate-to-distortion relationship, or for which the associated rate-to-distortion relationship at least satisfies the prediction mode selection criterion.

The intra prediction module 254 is further configured to determine the intra prediction block 255 based on an intra prediction parameter, such as the selected intra prediction mode. In any case, after selecting the intra prediction mode for the block, the intra prediction module 254 is also configured to transmit an intra prediction parameter, i.e. information indicating the selected intra prediction mode for that block to entropy encoding unit 270 . In one example, intra prediction module 254 may be configured to perform any combination of intra prediction methods, which will be described later.

In FIG. 3 shows an example of a video decoder 30 configured to implement the technology of the present application. This video decoder 30 is configured to receive encoded image data 21 (for example, an encoded data bitstream), for example, encoded by encoder 100, to obtain a decoded image 131. In the process of decoding video, decoder 30 receives video data, for example, an encoded bitstream video data representing image blocks of the encoded video slice and associated syntax elements, from video encoder 100.

In the example shown in FIG. 3, the decoder 30 includes an entropy decoding module 304, an inverse quantization module 310, an inverse transform processor module 312, a reconstruction module 314 (e.g., adder 314), a buffer 316, a loop filter 320, a decoded image buffer 330, and a prediction processor module 360. This prediction processor module 360 may include an inter prediction module 344 , an intra prediction module 354 , and a mode selection module 362 . Video decoder 30 may, in some examples, perform a decoding workflow substantially opposite to the encoding workflow described with respect to video encoder 100 shown in FIG. 2.

The entropy decoding module 304 is configured to entropy decode 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. , an intra prediction parameter, loop filter parameters, and/or other syntax elements. The entropy decoding module 304 is further configured to send the inter prediction parameters, the intra prediction parameter, and/or other syntax elements to the prediction processor module 360 . Video decoder 30 may receive syntax elements at the video slice level and/or at the video block level.

Inverse quantization module 310 may be functionally identical to inverse quantization module 110, inverse transform processor module 312 may be functionally identical to inverse transform processor module 112, reconstruction module 314 may be functionally identical to reconstruction module 114, buffer 316 may be functionally identical to buffer 116, loop filter 320 may be functionally identical to the loop filter 120 and the decoded image buffer 330 may be functionally identical to the decoded image buffer 130.

Prediction processor module 360 may comprise an inter prediction module 344 and an intra prediction module 354, where inter prediction module 344 may be functionally similar to inter prediction module 144 and intra prediction module 354 may be functionally similar to intra prediction module 154. Prediction processor module 360 is typically configured to perform block prediction and/or obtain block prediction 365 based on encoded data 21 and to receive or obtain (explicit or implicit) prediction related parameters and/or information regarding the selected prediction mode, for example , from entropy decoding module 304 .

When a video slice is encoded as an intra prediction (I) encoded slice, intra prediction module 354 of prediction processor module 360 is configured to generate predictive block 365 for a picture block from the current video slice based on signaled intra prediction 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 slice, the inter prediction module 344 (e.g., motion compensation module) from the prediction processor module 360 is configured to generate predictive blocks 365 for the video block from the current slice video based on motion vectors and other syntax elements received from module 304 entropy decoding. For inter prediction, predictive blocks may be generated from one of the reference pictures within the same reference picture list. The video decoder 30 may construct lists of reference frames, namely List 0 (List 0) and List 1 (List 1), using a default construction technique based on the reference pictures stored in the DPB 330.

Prediction processor module 360 is configured to determine prediction information for a video block from the current video slice by parsing motion vectors and other syntax elements and using that prediction information to generate predictive blocks for the current video block that is currently being decoded. For example, prediction processor module 360 uses some received syntax elements to determine the prediction mode (e.g., intra or inter prediction) used to encode video blocks from a video slice, the type of slice for inter prediction (e.g., slice B, slice P, or slice GPB) , information about building one or more lists of reference pictures for the slice in question, motion vectors for each block of inter-predictive video, the status of inter-prediction for each block of inter-predictive video from that slice, and other information for decoding blocks of video in the current video slice.

The inverse quantizer 310 is configured for inverse quantization, i. dequantization, quantized transform coefficients obtained in the data bit stream and decoded by entropy decoding module 304 . The inverse quantization procedure may comprise using the quantization parameters computed by video encoder 100 for each video block in the video slice under consideration to determine the amount of quantization, and likewise the amount of inverse quantization, to be applied.

The inverse transform processor module 312 is configured to apply an inverse transform, such as an inverse discrete cosine transform (DCT), an inverse integer transform, or a conceptually similar inverse transform procedure, to the transform coefficients to generate residual blocks in the pixel region.

Reconstruction module 314 (eg, adder 314) is configured to add inversely transformed block 313 (i.e., reconstructed residual block 313) to predicted block 365 to obtain reconstructed block 315 in the sample domain, for example, by summing the sample values of reconstructed residual block 313 and values of samples of the predicted block 365.

The loop filter module 320 (either in the coding loop or after the coding loop) is configured to filter the reconstructed block 315 to obtain the filtered block 321, for example, to smooth pixel transitions or to improve video quality in another way. In another example, loop filter module 320 may be configured to implement any combination of the filtering methods described later. The loop filter module 320 is designed to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters, such as a bidirectional filter or an adaptive loop filter (ALF). )), or sharpening filters or smoothing filters, or joint filters. Although the loop filter module 320 is shown in FIG. 3 as being in a loop filter, in other configurations, loop filter module 320 may be implemented as a post loop filter.

The decoded video blocks 321 in the frame or picture in question are then stored in a 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, via output 332, for presentation to or viewing by a user.

Other variations of video decoder 30 may be used to decode the compressed data bitstream. For example, decoder 30 may generate a video output stream without using loop filter module 320 . For example, non-transform decoder 30 may inversely quantize the residual signal directly without inverse transform processor module 312 for certain blocks or frames. In another implementation, video decoder 30 may include an inverse quantization module 310 and an inverse transform processor module 312 312 combined in a single block.

According to the HEVC/H.265 standard, there are 35 intra prediction modes. 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 spanning an angular range of 180° having a range of values of the intra prediction mode index from 2 to 34 m, shown by black arrows in Fig. 4. To capture arbitrary edge directions present in natural video, the number of directional intra prediction modes is increased from 33, as used in the HEVC coding standard, to 65. Additional directional modes are depicted by dotted arrows in FIG. 4, while planar mode and DC mode remain the same. It is worth noting that the range covered by the intra prediction modes may be wider than 180°. In particular, 62 directional 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 the Joint Research Model (JEM) platforms, only one pair of angle modes (namely, modes 2 and 66) has the opposite directionality, as shown in FIG. 4. To build a predictor, conventional angular modes take reference samples and (when necessary) filter them to obtain a sample predictor. The number of reference samples required to build a predictor depends on the length of the filter used for interpolation (for example, bilinear or cubic filters have lengths of 2 and 4, respectively).

In FIG. 7 shows an example of 67 intra prediction modes, for example, as proposed for VVC coding, a set of intra prediction modes composed of 67 intra prediction modes includes: planar mode (index 0), dc mode (index 1), and angular modes with indices 2 – 66, where the lower left corner mode shown in FIG. 7 has index 2, and the index numbering increases to index 66, corresponding to the uppermost right corner mode in FIG. 7.

In FIG. 10 is a simplified diagram of a network device 1300 according to one embodiment of the present invention. Network device 1300 is suitable for implementation of the considered options, as described here. This network device 1300 includes input ports 1310 and receive modules (Rx) 1320 for receiving data; a processor, logic unit, or central processing unit (CPU) 1330 for data processing; transmitting modules (Tx) 1340 and output ports 1350 for data transmission; and a storage device 1360 for storing data. Network device 1300 may also contain optoelectric (optical-to-electrical (OE)) components and electro-optical (electrical-to-optical (EO)), connected to input ports 1310, receiving modules 1320, transmitting modules 1340 and output ports 1350 for output or input of optical or electrical signals.

Processor 1330 is implemented in hardware and software. Processor 1330 may be implemented as one or more CPU chips, cores (eg, as a multi-core processor), field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), and digital signal processors (DSPs). Processor 1330 is in communication with input ports 1310, receiver modules 1320, transmitter modules 1340, output ports 1350, and storage devices 1360. Processor 1330 includes an encoder module 1370. Encoder module 1370 implements the embodiments described above. For example, encoding module 1370 implements, processes, prepares, or provides a variety of network functions. The introduction of the encoder module 1370 therefore provides a significant improvement in the functionality of the network device 1300 and transforms the network device 1300 into a different state. Alternatively, the encoding module is implemented as instructions stored in memory 360 and executed by processor 1330.

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

In FIG. 10 is a block diagram of hardware 1100 that can be used to implement various options. Apparatus 1100 may be source device 102 as shown in FIG. 1 or video encoder 200 as shown in FIG. 2 or destination device 104 as shown in FIG. 1 or video decoder 300 as shown in FIG. 3. In addition, hardware 1100 may host one or more of the described items. In some embodiments, apparatus 1100 is equipped with one or more input/output devices such as a speaker, microphone, mouse, touch screen, keypad, keyboard, printer, display, or other similar device. Apparatus 1100 may include one or more central processing units (CPUs) 1510, memory 1520, mass storage 1530, video adapter 1540, and I/O interface 1560 coupled to the bus. This bus may have one or more bus architectures of various types, including a memory bus or memory controller, a peripheral bus, a video bus, or the like.

The CPU 1510 may have any type of electronic data processor. The storage device 1520 may have or be any type of system storage device, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read only memory (ROM), a combination of such devices or other similar device. In one embodiment, the storage device 1520 may include a ROM for use in booting and a DRAM device for storing programs and data for use in executing programs. In some embodiments, the storage device 1520 is non-volatile. The mass storage device 1530 is some type of storage device that stores data, programs, and other information and makes that data, programs, and other information available via a bus. This mass storage device 1530 includes, for example, one or more devices from the group of solid state disk, hard disk drive, magnetic disk drive, optical drive, or other similar device.

Video adapter 1540 and I/O interface 1560 provide interfaces for connecting external input and output devices to hardware 1100. For example, hardware 1100 can create an interface for Structured Query Language (SQL) commands for clients. As illustrated here, examples of input and output devices include a display 1590 connected to a video adapter 1540, and any mouse/keyboard/printer combination 1570 connected to an input/output interface 1560. Other devices may be connected to the apparatus 1100, and additional or fewer interface cards may be used. For example, a serial interface board (not shown) can be used to create a serial interface for a printer.

Apparatus 1100 also includes one or more network interfaces 1550 having wired links, such as Ethernet cable or the like, and/or wireless links leading to access points or one or more communication networks 1580. The network interface 1550 allows the apparatus 1100 to communicate with remote devices via communication networks 1580. For example, network interface 1550 may provide communication with a database. In one embodiment, apparatus 1100 is connected to a local area network or a wide area communications network for processing data and communicating with remote devices such as other processor modules, the Internet, remote data stores, or the like.

Abbreviation definitions and glossary

CTU / CTB - Coding Tree Unit / Coding Tree Block

CU / CB - Coding unit / Coding Block

PU / PB - Prediction unit / Prediction block

TU/TB - Transform unit / Transform Block

HEVC - High Efficiency Video Coding

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

A number of video coding standards since the H.261 standard belong to the group of "hybrid lossy video codecs" (i.e., combine spatial and temporal sample-domain prediction and two-dimensional (2D) transform coding to apply quantization in the transformed domain). Each picture from a video sequence is usually broken into a plurality of non-overlapping blocks, and then encoding is usually done at the block level. In other words, in the encoder, the video is usually processed, i. encode, at the block (image block) level, for example, using spatial (intra-picture) prediction and temporal (between-picture) prediction to generate a predictive block, subtracting this predictive block from the current block (block currently being processed / to be processed at the moment) to obtain a residual block, transform this residual block, and quantize the residual block in the transformed region to reduce the amount of data to be transmitted (compression), while the decoder partially applies the reverse processing procedure to the encoded or compressed block compared to the encoder with the purpose of reconstructing the current block for presentation on the display. Moreover, the encoder duplicates the processing loop of the decoder so that both devices will generate identical prediction (eg, intra or inter prediction) and/or reconstruction results for processing, i. coding, subsequent blocks.

As used here, the term "block" may mean a portion of a picture (image) or frame. For convenience, embodiments of the present invention are described herein with reference to the High-Efficiency Video Coding (HEVC) standard or Versatile video coding (VVC) reference software developed by the Joint Video Coding Group ( Joint Collaboration Team on Video Coding (JCT-VC)), created by the Video Coding Experts Group (VCEG) in the telecommunications standardization sector of the international telecommunications union (ITU-T) and the Motion Picture Experts Group (Moving Picture Experts Group (MPEG)) International Organization for Standardization/International Electrotechnical Commission (ISO/IEC). Even an ordinary person skilled in the art should understand that the variants of the present invention are not limited to the HEVC or VVC coding standards. It can be based on CU units, PU units and TU units. In the HEVC coding standard, a CTU is broken down into CUs using a square tree structure called a coding tree. The decision on whether to encode a certain area of the image using mutual (temporal) or intra (spatial) prediction is made at the CU level. Each CU can be further subdivided into one, two or four PUs according to the type of PU subdivision. Within one PU, the same prediction procedure is applied, and related information is transmitted to the decoder based on the PUs. After obtaining the residual block by applying a prediction procedure based on the PU partitioning type, the CU can be partitioned into transform units (TUs) according to a different square tree structure similar to the coding tree for the CU in question. The latest development of video compression technology uses Quad-tree and binary tree (QTBT) partitioning to partition a coding block. In the block structure according to the QTBT tree, the CU can be either square or rectangular. For example, a coding tree unit (CTU) is first split according to a square tree structure. The side nodes ("leaf" nodes) of the square tree are then split according to the structure of the binary tree. The side nodes ("leaves") of a binary tree are also called coding units (CUs), and such segmentation is used for the prediction and transformation procedure without any further partitioning. This means that in the coding block structure of the QTBT tree, the CU, the PU, and the TU have the same block size. In parallel, along with the block structure of the QTBT tree, the use of other types of partitioning is also proposed, for example, partitioning according to a ternary tree.

The ITU-T VCEG (Q6/16) and ISO/IEC MPEG (JTC 1/SC 29/WG 11) Expert Groups are currently investigating the potential need for standardization of future video coding technologies that would greatly outperform video compression capabilities. capabilities of the current HEVC coding standard (including its current and near future extensions for screen content encoding and high dynamic range encoding). These groups work together on research in this area as part of a collaborative activity in a group called the Joint Video Experts Group (JVET) to evaluate compression technology options proposed by the group's expert members in the field.

The Versatile Test Model (VTM) standard uses 35 intra prediction modes, while the Benchmark Set (BMS) standard uses 67 intra prediction modes. To encode 67 intra prediction modes, the existing intra prediction mode coding scheme in the BMS standard uses the following method:

In order to accommodate the increased number of directional intra prediction modes, the BMS standard uses an intra prediction coding method using 6 most probable modes (Most Probable Mode (MPM)). There are two important technical aspects involved here.

1) derivation of 6 MPM modes, and

2) entropy encoding of these 6 MPM modes and non-MPM modes, i.e. non-MPM modes.

In the BMS standard, the modes included in the MPM mode lists are classified into three groups: Neighbor intra prediction modes, Derived intra prediction modes, and Default intra prediction modes.

The five adjacent intra prediction modes are used to form a list of MPM modes. The arrangement of the 5 adjacent blocks is the same as that used in the merge mode, i.e. left (L), top (A), bottom left (BL), top right (AR), and top left (AL) as shown in Figure 5. Accordingly, the prediction modes for these blocks have the same designations. The initial MPM mode list is formed by inserting 5 adjacent intra prediction modes, a planar mode, and a DC mode into the MPM mode list. A truncation procedure is used to remove duplicate modes so that only the unique modes remain in the MPM mode list. The initial modes are enabled in the following order - left, top, planar mode, DC mode, bottom left, top right, and top left.

When the list of MPM modes is incomplete (i.e., contains less than 6 candidate MPM modes in the list), derived modes are added, i.e. intra prediction modes whose indices are obtained by adding −1 or +1 to the indices of those angular modes already included in this list of MPM modes. The derivative modes derivation procedure does not apply to non-angular modes, i.e. to DC mode or planar mode.

Finally, if the list of MPM modes is still incomplete, default modes are added to it in the following order: vertical mode, horizontal mode, intra prediction mode (2), and diagonal mode. The result of this procedure is a unique list of 6 MPM modes.

For entropy encoding of the 6 MPM modes, a truncated unary binarization of these MPM modes is used. The first three packets are encoded with context depending on the MPM mode associated with the packet currently being signaled. The MPM mode under consideration falls into one of three classification categories: (a) whether it belongs to horizontal modes (the MPM mode index is not greater than the diagonal direction index), (b) to vertical modes (the MPM mode index is greater than the diagonal direction index), or ( c) to the class of non-angular modes (DC mode and planar mode). Accordingly, three contexts are used to signal the MPM mode index.

The remaining 61 non-MPM modes are coded as follows. These 61 non-MPM modes 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 remaining (45) modes are assigned to the set of unselected modes. The mode set to which the current mode belongs is indicated in the data bit stream by 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. A set of selected modes is generated by subsampling the indices of 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}

A summary of the signaling mechanisms for intra prediction modes is given in Table 1.

Table 1. Luminance Intra Prediction Mode Signaling in the BMS Standard

Intra prediction modes MPM Modes Flag Selection Flag binary string MPM Modes (6) one 0 ten 110 1110 11110 11111 Selected modes (16) Fixed length code 4 bits Unselected modes (45) Truncated Binary

In another example, a 3 most likely modes (MPM) intra prediction mode encoding method is used. In one example, the syntax elements intra_luma_mpm_flag[ x0 ][ y0 ], intra_luma_mpm_idx[ x0 ][ y0 ], and intra_luma_mpm_remainder[ x0 ][ y0 ] specify the intra-prediction mode for luma samples. The array indices x0, y0 specify the position (x0, y0) of the top-left luminance sample of the predicted block in question relative to the top-left luminance sample of the image. When the flag intra_luma_mpm_flag[ x0 ][ y0 ] is equal to 1, the intra prediction mode is output from the adjacent prediction unit processed by intra prediction.

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

Adjacent positions ( xNbA, yNbA ) and ( xNbB, yNbB ) are set to match ( xPb − 1, yPb ) and ( xPb, yPb − 1 ), respectively.

For X replaced by A or B, the candIntraPredModeX variables are obtained as follows:

The accessibility derivation procedure for a block is performed when the position ( xCurr, yCurr ) is set to be the same as ( xPb, yPb ) and the adjacent position ( xNbY, yNbY ) is set to be the same as ( xNbX, yNbX ) as input variables, and the output of this procedure is assigned as availableX .

The candidate intra prediction mode candIntraPredModeX is obtained as follows:

When one or more of the following conditions is true, the candIntraPredModeX parameter is set to INTRA_DC.

The availableX variable is FALSE.

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

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

Otherwise, the variable candIntraPredModeX is set to IntraPredModeY[ xNbX ][ yNbX ].

The candModeList[ x ] parameter for x = 0..2 is defined as follows:

When the parameter candIntraPredModeB is equal to candIntraPredModeA, the following applies:

When the parameter candIntraPredModeA is less than 2 (i.e. equal to INTRA_PLANAR or INTRA_DC), the parameter candModeList[ x ] when x = 0..2 is defined as follows:

candModeList[ 0 ] = INTRA_PLANAR

candModeList[ 1 ] = INTRA_DC

candModeList[ 2 ] = INTRA_ANGULAR50

Otherwise, the parameter candModeList[ x ] for x = 0..2 is defined 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:

The parameters candModeList[ 0 ] and candModeList[ 1 ] are defined as follows:

candModeList[ 0 ] = candIntraPredModeA

candModeList[ 1 ] = candIntraPredModeB

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

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

Otherwise, the parameter candModeList[ 2 ] is set to INTRA_ANGULAR50.

The IntraPredModeY[ xPb ][ yPb ] parameter is determined by applying the following procedure:

When the intra_luma_mpm_flag[ xPb ][ yPb ] is set to 1, the parameter IntraPredModeY[ xPb ][ yPb ] is set to candModeList[ intra_luma_mpm_idx[ xPb ][ yPb ] ].

Otherwise, IntraPredModeY[ xPb ][ yPb ] is determined by applying the following ordered steps:

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

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

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

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

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

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

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

The IntraPredModeY[ xPb ][ yPb ] parameter is determined through the following ordered steps:

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

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

In one form of implementation of the present application, a frame is the same as an image (picture).

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

determining whether a block to the left of the current coding block is available or not, if such a block to the left of the current coding block is available, adding an intra prediction mode with respect to this block to the left of the MPM mode list;

determining whether a block above the current coding block is available or not, if such a block above the current coding block is available, adding an intra prediction mode with respect to this block above to the MPM mode list;

when the planar mode is not included in the MPM mode list, adding the planar mode to the MPM mode list; when DC mode is not in the MPM mode list, add DC mode to the MPM mode list.

In one form of implementation of the present application, when there is (available) a block above the current coding block and the intra prediction mode relative to this block above is not in the MPM mode list, the intra prediction mode relative to this block above is added to the MPM mode list.

In one form of implementation of the present application, when there is (available) a block above the current coding block and the intra prediction mode relative to this block above is present in the list of MPM modes, “adding” is performed, or we can say that the result of the “adding” procedure is not changes the list of MPM modes.

In one embodiment of the present application, when the block-relative prediction mode on the left is not an intra prediction mode, the block to the left of the current coding block is unavailable.

In one form of implementation of the present application, when the current coding block is located on the extreme left side of its frame, the block to the left of the current coding block is not available.

In one form of implementation of the present application where parallel processing is supported and where the current coding block is a coding block located on the extreme left side of its tile, the block to the left of the current coding block is not available.

In one form of implementation of the present application where parallel processing is not supported and where the current coding block is a coding block located on the far left side of its tile, but not on the far left side of the frame, the block to the left of the current coding block is available.

In one form of implementation of the present application, where parallel processing is supported and where the current coding block is a coding block located on the extreme left side of its slice, the block to the left of the current coding block is not available.

In an embodiment of the present application where parallel processing is not supported and where the current coding block is a coding block located on the leftmost side of its slice, but not on the leftmost side of the frame, the block to the left of the current coding block is available.

In one embodiment of the present application, when the block-above prediction mode is not an intra prediction mode, the block-above from the current coding block is unavailable.

In one form of implementation of the present application, when the current coding block is a coding block located on the topmost side of its frame, the block above the current coding block is not available.

In an embodiment of the present application where parallel processing is supported and where the current coding block is a coding block located on the topmost side of its tile, the block above the current coding block is not available.

In an embodiment of the present application where parallel processing is not supported and where the current coding block is a coding block located on the topmost side of its tile, but not on the topmost side of the frame, the block above the current coding block is available.

In one form of implementation of the present application, where parallel processing is supported and where the current coding block is a coding block located on the uppermost side of its slice, the block above the current coding block is not available.

In an embodiment of the present application where parallel processing is not supported and where the current coding block is a coding block located on the topmost side of its tile, but not on the topmost side of the frame, the block above the current coding block is available.

In one embodiment of the present application, when the line buffer size is limited and when the current coding unit is a coding unit located on the uppermost side of the CTU, the block above the current coding unit is not available.

In one form of implementation of the present application, if the current coding block is a coding block that is not located on the far left side of the frame, the block to the left of the current coding block is available.

In one form of implementation of the present application, if the current coding block is a coding block that is not located on the topmost side of the frame, the block above the current coding block is available.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and adding this first intra prediction mode into the MPM mode list if this first intra prediction mode is not included in the MPM mode list, where the plurality of intra prediction modes contains vertical mode (VER_IDX index) (as the first intra prediction mode), horizontal mode (HOR_IDX index), intra prediction mode (index 2), vertical diagonal mode (index VDIA_IDX), or diagonal mode (index DIA_IDX).

In one form of implementation of the present application, the value corresponding to the index VER_IDX is equal to 50; the value corresponding to the HOR_IDX index is 18; the value corresponding to the index VDIA_IDX is equal to 66, and this value may be the largest value from the set of values corresponding to the angular modes; value 2 corresponding to intra prediction mode 2 may be the smallest value from a plurality of values corresponding to angular modes; the value corresponding to the DIA_IDX index is 34.

In one embodiment of the present application, when the number of intra prediction modes in the MPM mode list is less than a threshold, it is checked whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and the first intra prediction mode is added to the mode list. MPM if this first intra prediction mode is not included in the list of MPM modes, where the plurality of intra prediction modes contains vertical mode (VER_IDX index) (as the first intra prediction mode), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2 ), vertical, diagonal mode (index VDIA_IDX), or diagonal mode (index DIA_IDX).

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, iteratively adding an intra prediction mode from a plurality of intra prediction modes, containing a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index ), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index), according to the above order in the MPM mode list, when that intra prediction mode is not included in the MPM mode list, until the number of prediction modes in this list will not become equal to the threshold value.

In one form of implementation of the present application, this method further comprises: when the block to the left of the current coding block is not available and when the number of intra prediction modes in the MPM mode list is less than a threshold value, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the list of MPM modes, and adding this first intra prediction mode to the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where the plurality of intra prediction modes contains vertical mode (VER_IDX index) (as the first intra prediction mode), vertical diagonal mode (VDIA_IDX index), diagonal mode (DIA_IDX index), or intra prediction mode 2 (index 2).

In one form of implementation of the present application, this method further comprises: when the block to the left of the current coding block is not available and when the number of intra prediction modes in the MPM mode list is less than a threshold, iteratively adding an intra prediction mode from a plurality of intra prediction modes containing a vertical mode ( VER_IDX index), vertical diagonal mode (VDIA_IDX index), diagonal mode (DIA_IDX index), or intra prediction mode 2 (2), according to the above order into the MPM mode list, when the specified intra prediction mode is not in the MPM mode list, while the number of prediction modes in this list will not become equal to the threshold value.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and adding this first intra prediction mode into the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where the specified set of intra prediction modes contains a vertical mode (VER_IDX index) (as the first intra prediction mode), a horizontal mode (HOR_IDX index), an intra prediction mode prediction corresponding to the VER_IDX index with an offset of -4, or an intra prediction mode corresponding to the VER_IDX index with an offset of 4.

In one embodiment of the present application, the intra prediction mode corresponding to the VER_IDX index with an offset of -4 uses the value corresponding to the VER_IDX index to add an offset of -4 and obtain the index value of the corresponding intra prediction mode, for example, when the value of the VER_IDX index is 50, the intra prediction mode corresponding to the VER_IDX index with offset -4 is the intra prediction mode 46, the intra prediction mode corresponding to the VER_IDX index with offset 4 is the intra prediction mode 54 . Other offset examples are obtained using a procedure similar to this example.

Note that when shifting by -1 or +1, or another amount, this may cover the operation of moving around up or down, for example, if the index of the intra prediction mode is (2) (the smallest value of the set of values corresponding to the angular modes ), then the intra prediction mode with index (2)-1 will correspond to index 66 (up-circle case), or if the value of the VDIA_IDX index is 66 (the largest value of the set of values corresponding to the angular modes), then the index VDIA_IDX +1 will be is equal to 2 (case of transition in a circle downwards).

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, iteratively adding an intra prediction mode from a plurality of intra prediction modes, containing a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index ), the intra prediction mode corresponding to the VER_IDX index with an offset of -4, or the intra prediction mode corresponding to the VER_IDX index with an offset of 4, according to the above order in the MPM mode list, if the intra prediction mode in question is not included in the MPM mode list, while the number of prediction modes in this list will not become equal to the threshold value.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and adding this first intra prediction mode into the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where the specified set of intra prediction modes contains a vertical mode (VER_IDX index) (as the first intra prediction mode), a horizontal mode (HOR_IDX index), an intra prediction mode prediction corresponding to the VER_IDX index with an offset of 4, or an intra prediction mode corresponding to the VER_IDX index with an offset of -4.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, iteratively adding an intra prediction mode from a plurality of intra prediction modes, containing a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index ), the intra prediction mode corresponding to the VER_IDX index with offset 4, or the intra prediction mode corresponding to the VER_IDX index with offset -4, according to the above order in the MPM mode list, if this intra prediction mode is not included in the MPM mode list, while the number of prediction modes in this list will not become equal to the threshold value.

In one form of implementation of the present application, this method further comprises: when the block to the left of the current coding block is not available, and when the number of intra prediction modes in the MPM mode list is less than a threshold,

checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and adding this first intra prediction mode to the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where said plurality of intra prediction modes contains one of the following sets of intra prediction modes:

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

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

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

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

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

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

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

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

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

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

In one form of implementation of the present application, this method further comprises: when the block to the left of the current coding block is not available and when the number of intra prediction modes in the MPM mode list is less than a threshold, iteratively adding an intra prediction mode from a plurality of intra prediction modes in accordance with the above in order in the list of MPM modes, if the considered intra prediction mode is not included in the list of MPM modes, until the number of prediction modes in this list becomes equal to a threshold value;

where said set of intra prediction modes contains one of the following sets of intra prediction modes:

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

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

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

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

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

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

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

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

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

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

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, and the block above the current coding block is not available, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the list of MPM modes, and adding this first intra prediction mode to the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where the plurality of intra prediction modes contains a horizontal mode (HOR_IDX index) (as the first intra prediction mode), mode 2 intra prediction (index 2), diagonal mode (DIA_IDX index), or vertical diagonal mode (VDIA_IDX index).

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, and a block above the current coding block is not available, iteratively adding an intra prediction mode from a plurality of intra prediction modes containing a horizontal mode ( HOR_IDX index), intra prediction mode 2 (index 2), diagonal mode (DIA_IDX index), or vertical diagonal mode (VDIA_IDX index), according to the above order into the MPM mode list, if this intra prediction mode is not included in the MPM mode list until the number of prediction modes in this list is equal to the threshold value.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, and the block to the left of the current coding block is available, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the list MPM modes, and adding this first intra prediction mode to the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where the specified set of intra prediction modes contains a vertical mode (VER_IDX index) (as the first intra prediction mode), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index).

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold, and the block to the left of the current coding block is available, iteratively adding an intra prediction mode from a set of intra prediction modes containing a vertical mode ( VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index), according to the above order in the MPM mode list, when the specified intra mode prediction mode is not included in the MPM mode list until the number of prediction modes in the list is equal to a threshold.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, and the block above the current coding block is not available, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the list MPM modes, and adding this first intra prediction mode to the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where the specified set of intra prediction modes contains a horizontal mode (HOR_IDX index) (as the first intra prediction mode), intra prediction mode 2 (index 2), diagonal mode (DIA_IDX index), or vertical diagonal mode (VDIA_IDX index).

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold, and the block above the current coding block is not available, iteratively adding an intra prediction mode from an intra prediction mode set containing a horizontal mode ( HOR_IDX index), intra prediction mode 2 (index 2), diagonal mode (DIA_IDX index), or vertical diagonal mode (VDIA_IDX index), according to the above order into the MPM mode list, when the specified intra prediction mode is not included in the MPM mode list until the number of prediction modes in this list is equal to the threshold value.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, the block to the left of the current coding block is available and the block above the current coding block is available, checking if the first intra prediction mode is included of the plurality of intra prediction modes to the MPM mode list, and adding that first intra prediction mode to the MPM mode list if the first intra prediction mode is not included in the MPM mode list, where said plurality of intra prediction modes contains a vertical mode (VER_IDX index) (in as the first intra prediction mode), a horizontal mode (HOR_IDX index), an intra prediction mode corresponding to a VER_IDX index with an offset of -4, or an intra prediction mode corresponding to a VER_IDX index with an offset of 4.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, the block to the left of the current coding block is available and the block above the current coding block is available, iteratively adding an intra prediction mode from a plurality of modes an intra prediction mode comprising a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index), an intra prediction mode corresponding to a VER_IDX index with an offset of -4, or an intra prediction mode corresponding to a VER_IDX index with an offset of 4, according to the above order in the list MPM modes when that intra prediction mode is not included in the list of MPM modes until the number of prediction modes in the list is equal to a threshold.

In one embodiment of the present application, this method further comprises: when a block upstream of the current coding block is not available, and when the number of intra prediction modes in the MPM mode list is less than a threshold, checking whether the first intra prediction mode of the plurality of intra prediction modes is in a list of MPM modes, and adding this first intra prediction mode to the list of MPM modes, if this first intra prediction mode is not included in the list of MPM modes, where the specified set of intra prediction modes contains one of the following sets of intra prediction modes:

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

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

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

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

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

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

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

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

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

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

In one form of implementation of the present application, this method further comprises: if a block above the current coding block is not available and if the number of intra prediction modes in the MPM mode list is less than a threshold, iteratively adding an intra prediction mode from a plurality of intra prediction modes in accordance with the above in order in the list of MPM modes, when the considered intra prediction mode is not included in the list of MPM modes, until the number of prediction modes in this list becomes equal to a threshold value; where said set of intra prediction modes contains one of the following sets of intra prediction modes:

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

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

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

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

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

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

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

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

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

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

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, iteratively adding an intra prediction mode from a plurality of intra prediction modes, containing a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index ), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index), according to the above order in the MPM mode list, when that intra prediction mode is not included in the MPM mode list, until the number of prediction modes in this list will not become equal to the threshold value.

In one form of implementation of the present application, this method further comprises: when the block to the left of the current coding block is not available, and when the number of intra prediction modes in the MPM mode list is less than a threshold value, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in a list of MPM modes, and adding this first intra prediction mode to the MPM mode list if this first intra prediction mode is not included in the MPM mode list, where the set of intra prediction modes contains a vertical mode (VER_IDX index) and a vertical diagonal mode (VDIA_IDX index) , a diagonal mode (index DIA_IDX) or intra prediction mode 2 (index 2).

In one form of implementation of the present application, this method further comprises: when the block to the left of the current coding block is not available and when the number of intra prediction modes in the MPM mode list is less than a threshold, iteratively adding an intra prediction mode from a plurality of intra prediction modes containing a vertical mode ( VER_IDX index), vertical diagonal mode (VDIA_IDX index), diagonal mode (DIA_IDX index), or intra prediction mode 2 (index 2), according to the above order into the MPM mode list, when the intra prediction mode in question is not included in the MPM mode list until the number of prediction modes in this list is equal to the threshold value.

In one embodiment of the present application, it may be understood that adding any intra prediction mode to the MPM mode list is adding the value corresponding to that intra prediction mode to the MPM mode list.

In one form of implementation of the present application, the threshold value is 6.

According to one aspect of the present application, the encoder contains a processor circuit for implementing the above methods.

According to one aspect of the present application, the decoder includes a processor circuit for implementing the above methods.

According to one aspect of the present application, the computer program product contains program code for implementing the above methods.

According to one aspect of the present application, the decoder for building a list of the most probable modes, MPM, contains: one or more processors; and a non-volatile computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the programs, when executed by the processors, configure a decoder to perform the methods described above.

According to one aspect of the present application, the encoder for building a list of the most likely modes, MPM, contains: one or more processors; and a non-volatile computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the programs, when executed by the processors, configure an encoder to perform the methods described above.

In one of the examples

Step one: determining if a block is available to the left of the current encoding block or not.

When a block to the left of the current coding block is available, add an intra prediction mode relative to that block to the left of the MPM mode list. This MPM mode list may be an empty list, when the block to the left of the current coding block is available, the intra prediction mode relative to this block to the left is added to this MPM mode list, after that, the MPM mode list contains one intra prediction mode; and when the block to the left of the current coding block is not available, the MPM mode list is still empty after completion of step one.

Step two: determining if a block is available above the current encoding block or not.

When a block above the current coding block is available, the intra prediction mode relative to this block above is added to the list of MPM modes. This list of MPM modes may contain an intra prediction mode relative to the block on the left, or still remain an empty list.

When a block above the current coding block is available and when the MPM mode list contains an intra prediction mode relative to the block on the left, it is next to determine whether the intra prediction mode relative to the specified block above is the same as the intra prediction mode relative to the specified block left, when these modes match, the result of the step of "adding the block-upward intra prediction mode to the MPM mode list" does not change the number of intra prediction modes in the MPM mode list, this MPM mode list contains only one intra prediction mode; if the intra prediction mode for the specified block from above is not the same as the intra prediction mode for the specified block from the left, then the intra prediction mode for the specified block from above is added to the MPM mode list, and then this MPM mode list already contains two intra prediction modes.

When a block above the current coding block is available and when the MPM mode list is still an empty list, an intra prediction mode relative to the specified block above is added to the MPM mode list, after which this MPM mode list contains only one intra prediction mode.

When the block above the current coding block is not available, and when the MPM mode list contains the intra prediction mode relative to the left block, the MPM mode list will still only contain the intra prediction mode relative to the left block.

When the block above the current encoding block is not available and the MPM mode list is still an empty list, then the MPM mode list will still be an empty start.

Step three: when the planar mode is not in the MPM mode list, adding the planar mode to the MPM mode list.

If, after step two, the MPM mode list does not contain a planar mode, then adding that planar mode to the MPM mode list.

When both the intra block-left intra prediction mode and the block-up intra prediction mode are not available, or the available intra prediction mode is not a planar mode, the MPM mode list does not contain a planar mode.

If planar mode is present in the MPM mode list, go to step four.

Step four: when the DC mode is not in the MPM mode list, add this DC mode to the MPM mode list.

If, after step two or step three, the MPM mode list does not contain a DC mode, then the DC mode is added to the MPM mode list.

When both the intra block-left intra prediction mode and the block-up intra prediction mode are not available, or the available intra prediction mode is not the DC mode, then the MPM mode list does not contain the DC mode.

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

In one form of implementation of the present application, at each step, when performing the procedure for adding any prediction mode to the list of MPM modes, it is necessary to make sure that there is no duplicate prediction mode in this list of MPM modes. Therefore, when the intra prediction mode to be added to the MPM mode list is the same as one of the intra prediction modes already present in this MPM mode list, the "add" procedure does not change the MPM mode list, or this "add" procedure is not performed.

In one form of implementation of the present application, after step 4, only if there is an angular mode, then index assignment is performed - angular mode index - 1 (angular-1), angular mode index + 1 (angular+1).

In one example, when the number of intra prediction modes in the MPM mode list is six, after step four, three cases are possible regarding the length of the MPM mode:

Case 1: MPM mode length is 2: → modes relative to both blocks - left (L) and top (A) are not angular (>DC) or not available, only planar mode and DC mode in → use all four modes by default.

Case 2: The length of the MPM mode is 3: → the mode with respect to one of the blocks L or A is angular, or they are the same angular. → use one default mode.

Case 3: MPM mode length is 4: → modes with respect to both blocks L and A are angular and different from one another → default modes are not used because at least one of the modes with indices L-1, L+1 must be added. When one of these modes is a duplicate of the above (diff(L-A)=1), then at least one of the modes with indices A-1 and A+1 must be additionally inserted.

In one form of implementation of the present application, the method further comprises: when a block to the left of the current coding block is available and when the intra prediction mode relative to this block to the left is an angular mode, adding a shift to the prediction mode index relative to the block to the left to obtain a new prediction mode when this new prediction mode is not in the list of MPM modes, adding this new prediction mode to the list of MPM modes.

In another example, the MPM mode list contains six intra prediction modes because the above four steps can only obtain four intra prediction modes in the largest case. This method additionally contains:

Step five: when a block to the left of the current coding block is available and when the intra prediction mode relative to that block to the left is corner mode, adding an offset to the prediction mode index relative to the block to the left to obtain a new prediction mode, and when this new prediction mode is not in the list MPM modes, adding this new prediction mode to the list of MPM modes.

For example, when the block to the left of the current coding block has an angle mode of 27 (the index value corresponding to this intra prediction angle mode is 27), and the list of MPM modes after the above four steps is (27, 15, 0, 1). A shift is added to the prediction mode index with respect to the block on the left to obtain a new prediction mode when this new prediction mode is not included in the MPM mode list, and this new prediction mode is added to the MPM mode list. In one example, this offset is -1, so that the index of this new prediction mode is 26, and the updated list of MPM modes is (27, 15, 0, 1, 26). In another example, this shift is 1, so the index of this new prediction mode is 28, and the updated list of MPM modes is (27, 15, 0, 1, 28). In another example, in step five, two amounts of shifts may be added to the intra prediction mode index relative to the block on the left, first adding -1 and then adding 1, or first adding 1 and then adding -1, so that the updated list of MPM modes may be (27, 15, 0, 1, 26, 28) or (27, 15, 0, 1, 28, 26).

After step five, it is checked whether the MPM mode list is full (When the number of intra prediction modes in the MPM mode list is equal to a threshold, for example, this threshold is 6, then the MPM mode list is full. If the number of intra prediction modes in the MPM mode list is less than the threshold values, then the list of MPM modes is empty). When the MPM mode list is full, the MPM mode list building procedure is terminated; when the MPM mode list is empty, proceed to the next steps.

And when the block to the left of the current coding block is unavailable, step five is not performed, but proceeds to the next steps.

Note that the procedure for adding an offset (eg, -1 or +1) to the index of the angular mode of prediction, should contain the operation of moving around the circle up or down, for example. When the prediction angular mode index relative to the block left (angularLeft) is 2, then the angularLeft-1 mode index will be 66 (circle up operation case), or when the angularLeft mode index is 66, then the angularLeft+1 mode index will be 2 ( the case of the operation of moving around the circle down).

In one form of implementation of the present application, this method further comprises: when a block above the current coding block is available, and when the intra prediction mode relative to this block above is angular mode, adding an offset to the prediction mode index relative to the block above to obtain the shifted mode index block-up prediction, if this offset block-up prediction mode is not in the MPM mode list, adding this offset block-up prediction mode to the MPM mode list.

In one example, this method further comprises:

Step six: when a block up from the current coding block is available, and when the intra prediction mode with respect to that block up is an angle mode, adding an offset to the block up prediction mode index to obtain an offset prediction mode index with respect to the block up, and if this offset mode block top prediction is not in the MPM mode list, adding this new prediction mode to the MPM mode list.

For example, the block-upward prediction mode of the current coding block is angle mode 26 (the index value corresponding to this intra prediction angle mode is 26), and the list of MPM modes after the above five steps is (27, 26, 0, 1, 28). Adding an offset to the block-up prediction mode index on the left to obtain an index of the block-up offset prediction mode, when this block-up offset prediction mode is not included in the MPM mode list, adding this block-up offset prediction mode to the MPM mode list. In one example, the offset value is -1, then the offset prediction mode index relative to the top block is 25 and the updated list of MPM modes is (27, 26, 0, 1, 28, 25). In another example, if the offset value is 1, then the block-up offset prediction mode index is 27, and insertion of this block-up offset prediction mode index of 27 is blocked because mode 27 has already been inserted. In another example, in step six, two offset values can be added to the intra prediction mode index relative to the top block, adding -1 first and then adding 1, or adding 1 first and then adding -1 if the list of MPM modes is still incomplete. after adding one shift.

And when the block above the current coding block is not available, step six is not performed, but proceeds to the next steps. After step six, it is checked whether the MPM mode list is full (the number of intra prediction modes in the MPM mode list is 6). When the MPM mode list is full, the construction of the MPM mode list is completed; if the MPM mode list is empty (the number of intra prediction modes in the MPM mode list is less than 6), proceed to the next steps.

In one form of implementation of the present application, this method further comprises:

when the number of intra prediction modes in the MPM mode list is less than a threshold value (eg, the threshold value is 6), the default list is used to build the MPM mode list.

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

In one example, when the number of intra prediction modes in the MPM mode list is less than a threshold, the default list contains a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index), a VER_IDX index mode with an offset of -4, or a VER_IDX index mode. with added shift 4.

In one example, when the number of intra prediction modes in the MPM mode list is less than a threshold, the default list contains a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index), a VER_IDX index mode with an added offset of 4, or a VER_IDX index mode with added shift -4.

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

vertical mode (VER_IDX index), vertical diagonal mode (VDIA_IDX index), diagonal mode (DIA_IDX index), or intra prediction mode 2 (index 2); or

vertical mode (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VER_IDX index mode with offset -1 added, and VER_IDX index mode with offset 1 added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VER_IDX index mode with offset -4 added, and VER_IDX index mode with offset 4 added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VDIA_IDX index mode with -4 offset added, and VER_IDX index mode with -1 offset added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VDIA_IDX index mode with -4 offset added, and VER_IDX index mode with +1 offset added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VDIA_IDX index mode with -1 offset added, and VER_IDX index mode with -1 offset added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VDIA_IDX index mode with offset -1 added, and VER_IDX index mode with offset 1 added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VER_IDX index mode with -1 offset added, and VDIA_IDX index mode with -4 offset added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VER_IDX index mode with offset 1 added, and VDIA_IDX index mode with offset -4 added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VER_IDX index mode with -1 offset added, and VDIA_IDX index mode with -1 offset added; or

vertical modes (VER_IDX index), vertical diagonal mode (VDIA_IDX index), VER_IDX index mode with offset 1 added, and VDIA_IDX index mode with offset -1 added.

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

horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), diagonal mode (DIA_IDX index), or vertical diagonal mode (VDIA_IDX index).

In one example, when the number of intra prediction modes in the MPM mode list is less than a threshold, the block to the left of the current coding block is available, and the block above the current coding block is available, the default list contains:

vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index); or

vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), VER_IDX index mode with offset -4 added, or VER_IDX index mode with offset 4 added; or

vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), VER_IDX index mode with an offset of 4, or VER_IDX index mode with an offset of -4 added.

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

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

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), HOR_IDX index mode with offset -4 added, and HOR_IDX index mode with offset 4 added; or

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), intra prediction mode 2 (2) with offset 4 added, and HOR_IDX index mode with offset -1 added; or

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), intra prediction mode 2 (2) with shift added 4, and shift added HOR_IDX index mode 1; or

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), intra prediction mode 2 (index 2) with offset 1 added, and HOR_IDX index mode with offset -1 added; or

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), intra prediction mode 2 (index 2) with shift added 1, and shift added HOR_IDX index mode 1; or

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), HOR_IDX index mode with offset -1 added, and intra prediction mode 2 (index 2) with offset index 4; or

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), shift-added HOR_IDX index mode 1, and intra-prediction mode 2 (index 2) with shift-added index 4; or

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), HOR_IDX index mode with offset -1 added, and intra prediction mode 2 (index 2) with offset index 1; or

horizontal modes (HOR_IDX index), intra prediction mode 2 (index 2), shift-added HOR_IDX index mode 1, and intra-prediction mode 2 (index 2) with shift-added index 1.

In one form of implementation of the present application, when the block to the left of the current coding block is not available, the block above the current coding block may or may not be available.

In one form of implementation of the present application, when the block above the current coding block is not available, the block to the left of the current coding block may or may not be available.

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

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and adding this first intra prediction mode into the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where the specified set of intra prediction modes contains vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (index VDIA_IDX) or diagonal mode (index DIA_IDX).

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold value, iteratively adding an intra prediction mode from a plurality of intra prediction modes, containing a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index ), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index), according to the above order in the MPM mode list, if the intra prediction mode in question is not included in the MPM mode list, while the number of prediction modes in this list will not become equal to the threshold value.

In one example, after step six, when the MPM mode list is still incomplete (the number of intra prediction modes in the MPM mode list is less than a threshold), adding an intra prediction mode from the default mode list is ordered to the MPM mode list when this mode or these modes are not included in the MPM mode list, this procedure is performed iteratively until the MPM mode list is full.

Step seven: adding vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index) to the MPM mode list.

For example, when the vertical mode is not included in the MPM mode list and the MPM mode list is not filled, adding this vertical mode to the MPM mode list, if the MPM mode list is full after adding this vertical mode, the MPM mode list is completed.

And if, after adding this vertical mode, the list of MPM modes is still empty, it is checked whether the horizontal mode is included in the list of MPM modes. When the horizontal mode is included in the MPM mode list, next, it is checked whether intra prediction mode 2 is included in the MPM mode list; if the horizontal mode is not included in the MPM mode list, the horizontal mode is added to the MPM mode list. This step is performed iteratively until the list of MPM modes is full.

In one form of implementation of the present application, at Step seven, if there are default mode lists, each time a default mode is inserted into the MPM mode list, it must be ensured that there are no duplicate modes. When the insertion is successful, another check is made to determine if the list of MPM modes is full. If the list is full, the MPM mode list filling procedure is terminated; otherwise, continue inserting the other default modes in the given order.

In one form of implementation of the present application, this method further comprises: when the block to the left of the current coding block is not available and the number of intra prediction modes in the MPM mode list is less than a threshold,

checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and adding this first intra prediction mode to the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where said plurality of intra prediction modes contains vertical mode (VER_IDX index), vertical diagonal mode (VDIA_IDX index), diagonal mode (DIA_IDX index), or intra prediction mode 2 (index 2).

In one form of implementation of the present application, this method further comprises:

when the block to the left of the current coding block is not available and when the number of intra prediction modes in the MPM mode list is less than a threshold,

iteratively adding an intra prediction mode from a plurality of intra prediction modes comprising vertical mode (VER_IDX index), vertical diagonal mode (VDIA_IDX index), diagonal mode (DIA_IDX index), or intra prediction mode 2 (index 2), according to the above order in a list of MPM modes, if the intra prediction mode in question is not included in the list of MPM modes, until the number of prediction modes in the list is equal to a threshold.

In one example, after step six, when the MPM mode list is still empty and when the block to the left of the current coding block is not available, add intra prediction modes from the default mode list in order to the MPM mode list when that mode or those modes are not are in the MPM mode list, this step is performed iteratively until the MPM mode list is full.

Step seven: adding vertical mode (VER_IDX index), vertical diagonal mode (VDIA_IDX index), diagonal mode (DIA_IDX index), or intra prediction mode 2 (index 2) to the MPM mode list.

For example, when the vertical mode is not included in the MPM mode list and the MPM mode list is not filled, add this vertical mode to the MPM mode list, if after adding this vertical mode the MPM mode list is full, complete the construction of the MPM mode list.

And if the MPM mode list is still empty after adding the vertical mode, it is checked whether the vertical diagonal mode is included in the MPM mode list. If this vertical diagonal mode is included in the MPM mode list, then it is checked whether the diagonal mode is included in the MPM mode list; if this diagonal mode is not included in the MPM mode list, add this diagonal mode to the MPM mode list. This step is performed iteratively until the list of MPM modes is full.

In one form of implementation of the present application, this method further comprises:

when the number of intra prediction modes in the MPM mode list is less than a threshold, and when a block upstream of the current coding block is unavailable, checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and adding the first intra prediction mode to the list MPM modes, if this first intra prediction mode is not included in the list of MPM modes, where the specified set of intra prediction modes contains a horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), a diagonal mode (DIA_IDX index), or a vertical diagonal mode ( VDIA_IDX index).

In one form of implementation of the present application, this method further comprises:

when the number of intra prediction modes in the MPM mode list is less than a threshold, and when a block upstream of the current coding block is not available, iteratively adding an intra prediction mode from a plurality of intra prediction modes containing a horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2) , diagonal mode (DIA_IDX index) or vertical diagonal mode (VDIA_IDX index), according to the above order in the MPM mode list, if the intra prediction mode in question is not in the MPM mode list, until the number of prediction modes in the list equals the threshold size.

In one example, after step six, when the MPM mode list is still empty, and when the block above the current coding block is not available, adding an intra prediction mode from the default mode list is ordered to the MPM mode list when that mode or those modes are not included in the MPM mode list, this step is performed iteratively until the MPM mode list is full.

Step seven: adding a horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), a diagonal mode (DIA_IDX index), or a vertical diagonal mode (VDIA_IDX index) to the MPM mode list.

For example, if the horizontal mode is not included in the MPM mode list and this MPM mode list is not filled, add this horizontal mode to the MPM mode list, if the MPM mode list is filled after adding the horizontal mode, complete the construction of the MPM mode list.

And if the MPM mode list is still empty after adding the indicated horizontal mode, it is checked whether intra prediction mode 2 is included in the MPM mode list. If intra prediction mode 2 is included in the MPM mode list, then it is checked whether the diagonal mode is included in the MPM mode list; if this diagonal mode is not included in the MPM mode list, add this diagonal mode to the MPM mode list. This step is performed iteratively until the list of MPM modes is full.

In one form of implementation of the present application, this method further comprises: when the number of intra prediction modes in the MPM mode list is less than a threshold, the block to the left of the current coding block is available and the block above the current coding block is available,

checking whether the first intra prediction mode of the plurality of intra prediction modes is included in the MPM mode list, and adding this first intra prediction mode to the MPM mode list, if this first intra prediction mode is not included in the MPM mode list, where the plurality of intra prediction modes contains vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index).

In one form of implementation of the present application, this method further comprises:

when the number of intra prediction modes in the MPM mode list is less than a threshold, the block to the left of the current coding block is available and the block upstream of the current coding block is available, iteratively adding an intra prediction mode from a plurality of intra prediction modes containing a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index), according to the above order into the MPM mode list, if the considered intra prediction mode is not in the mode list MPM until the number of prediction modes in this list equals a threshold.

In one example, after step six, if the MPM mode list is still empty, the block to the left of the current coding block is available, and the block above the current coding block is also available, add an intra prediction mode from the default mode list to the MPM mode list if this mode or these intra prediction modes is not included in the MPM mode list, this step is performed iteratively until the MPM mode list is full.

Step seven: adding vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index) to the MPM mode list.

For example, if the vertical mode is not included in the MPM mode list and the MPM mode list is not filled, add the vertical mode to the MPM mode list, if the MPM mode list is full after adding this vertical mode, complete the MPM mode list.

And if this MPM mode list is still empty after adding the specified vertical mode, it is checked whether the horizontal mode is included in the MPM mode list. If the horizontal mode is included in the MPM mode list, it is additionally checked whether intra prediction mode 2 is included in the MPM mode list; if this intra prediction mode 2 is not included in the MPM mode list, intra prediction mode 2 is added to the MPM mode list. This step is performed iteratively until the list of MPM modes is full.

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

In one embodiment of the present application, this method further comprises: adding vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), VER_IDX index mode with an offset of 4, or VER_IDX index mode with an offset of -4 added to the MPM mode list.

In one example, after step six, if the MPM mode list is still empty, add an intra prediction mode from the default mode list to the MPM mode list, if that mode or those modes are not included in the MPM mode list, iteratively perform this step until until the list of MPM modes is full.

Step seven: adding vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), VER_IDX index mode with offset -4 added, or VER_IDX index mode with offset 4 added to the MPM mode list; or adding vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), VER_IDX index mode with offset 4 added, or VER_IDX index mode with offset -4 added to the list of MPM modes.

For example, if the vertical mode is not included in the MPM mode list and this MPM mode list is not filled, add the vertical mode to the MPM mode list, if the MPM mode list is filled after adding this vertical mode, complete the construction of the MPM mode list.

And if the MPM mode list is still empty after adding the specified vertical mode, it is checked whether the horizontal mode is included in the MPM mode list. If this horizontal mode is included in the MPM mode list, it is further checked whether a prediction mode whose index value is equal to the VER_IDX index value with an offset of -4 added is included in the MPM mode list; if the prediction mode whose index value is equal to the VER_IDX index value with offset -4 added is not in the MPM mode list, the prediction mode whose index value is equal to the VER_IDX index value with offset -4 added is added to the MPM mode list. This step is performed iteratively until the list of MPM modes is full.

In one example, after step six, if the MPM mode list is still empty and if the block to the left of the current coding block is not available, add an intra prediction mode from the default mode list to the MPM mode list if that mode or those modes are not included. to the MPM mode list, this step is iteratively performed until the MPM mode list is full.

Step seven: adding vertical mode (VER_IDX index), vertical diagonal mode (VDIA_IDX index), diagonal mode (DIA_IDX index), or intra prediction mode 2 (index 2) to the MPM mode list.

For example, if the vertical mode is not included in the MPM mode list and if the MPM mode list is not filled, add this vertical mode to the MPM mode list, if after adding this vertical mode the MPM mode list is full, complete the construction of this MPM mode list.

And if, after adding this vertical mode, the MPM mode list is still empty, it is checked whether the vertical diagonal mode is included in this MPM mode list. If this vertical diagonal mode is included in the MPM mode list, then it is checked whether the diagonal mode is included in this MPM mode list; if this diagonal mode is not included in the MPM mode list, add this diagonal mode to the MPM mode list. This step is performed iteratively until the list of MPM modes is full.

In one example, after step six, if the MPM mode list is still empty and if the block upstream of the current coding block is not available, add an intra prediction mode from the default mode list to the MPM mode list if that mode or those modes are not enter the MPM mode list, iteratively perform this step until the MPM mode list is full.

Step seven: adding a horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), a diagonal mode (DIA_IDX index), or a vertical diagonal mode (VDIA_IDX index) to the MPM mode list.

For example, when the horizontal mode is not included in the MPM mode list, and this MPM mode list is not filled, add this horizontal mode to the MPM mode list, if after adding this horizontal mode the MPM mode list is full, complete the construction of this MPM mode list.

And if the MPM mode list is still empty after adding the horizontal mode, it is checked whether intra prediction mode 2 is included in the MPM mode list. When this intra prediction mode 2 is included in the MPM mode list, it is additionally checked whether the diagonal mode is included in the MPM mode list; if this diagonal mode is not in the MPM mode list, add this diagonal mode to the MPM mode list. This step is performed iteratively until the list of MPM modes is full.

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

Step seven: adding vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), VER_IDX index mode with offset -4 added, or VER_IDX index mode with offset 4 added to the MPM mode list.

In one example, preset default modes are prepared: namely, vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (index DIA_IDX) to build a list of MPM modes when that list is empty. Two additional approaches have been proposed regarding these default modes. This is the default adaptive approach and the modified default approach.

The adaptive modes approach considers blocks located on the left edge and on the top edge of the frame.

For blocks located on the left border of the frame, the horizontal mode is hardly used, since the initial samples for prediction, which in this case should be located in the block to the left of the current block, do not exist. Also, modes that generally use horizontal modes (ie, the mode with index DIA_IDX, mode 2) are less likely to be applied.

For blocks located at the upper frame boundary, the vertical mode is hardly used, since the initial samples for prediction, which in this case should be located in the block above the current block, do not exist. Also, modes that generally use vertical modes (ie, modes with VDIA_IDX, DIA_IDX indexes) are less likely to be applied.

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

When a block to the left of the current coding block does not exist, then use the following modes in the order of enumeration as candidate default modes: modes with indices VER_IDX, VDIA_IDX, DIA_IDX, and mode 2.

Otherwise (the block on the left exists):

When a block above the current coding block does not exist, then use the following modes in the order of enumeration as candidate default modes: mode with index HOR_IDX, mode 2, modes with indices DIA_IDX, VDIA_IDX.

Otherwise (top block exists), default normal modes are used: VER_IDX, HOR_IDX index modes, intra prediction mode 2 (2), VDIA_IDX index mode, or DIA_IDX index mode.

The modified default mode approach adds the following candidate default modes to the list of MPM modes: modes indexed VER, HOR, VER-4, VER+4. The order of modes with indices VER-4 and VER+4 can be exchanged.

One of the combinations of these two methods can be:

When the block to the left of the current coding block does not exist, then use the following modes in the order of enumeration as candidate default modes: modes with indices VER_IDX, VDIA_IDX, DIA_IDX, mode 2.

Otherwise (the block on the left exists):

When a block above the current coding block does not exist, then use the following modes in the order of enumeration as candidate default modes: mode with index HOR_IDX, mode 2, modes with indices DIA_IDX, VDIA_IDX.

Otherwise (the block above exists), the modified default modes are used: modes with indices VER_IDX, HOR_IDX, VER, HOR, VER-4, VER+4.

According to one aspect of the present invention, a simplified method for constructing a 6-input MPM mode list is proposed, comprising: checking the availability of a block to the left of the current coding units. The position of this block on the left is illustrated in Fig. 5, where this block is labeled “L” on the left.

The block on the left is unavailable when intra prediction information (ie, intra prediction mode) cannot be output from that block on the left. This includes the following cases:

The block on the left is not a block predicted in the intra prediction mode. The block on the left does not exist, for example, the current block is a coding block located on the left edge of the frame. When the encoder or decoder supports parallel processing, the block on the left can be considered non-existent (or inaccessible) when it is located in a tile other than the tile where the current block is, i.e. this current coding block is or was located on the left edge of the tile.

In another example, when the encoder or decoder does not support parallel processing, the block on the left can be considered available when it is in different tiles from the current block, i.e. the current encoding block is located on the left edge of the tile.

When the encoder or decoder supports parallel processing, the block on the left can be considered non-existent when it and the current block are in different slices, i.e. the current coding block is located on the left edge of the slice.

In another example, when the encoder or decoder does not support parallel processing, the block on the left can be considered available when it is located in different slices from the current block, i.e. the current coding block is located on the left edge of the slice.

The opposite case (ie, the block on the left is available) contains the intra prediction mode relative to the block on the left in the 6-entry MPM mode list.

Check the accessibility of the block from above with respect to the current coding units. The location of such a block from above is illustrated in Fig. 5, where this block is labeled “A” at the top.

The top block is unavailable when intra prediction information (ie, intra prediction mode) cannot be output from this top block. This includes the following cases:

The block on top is not a block predicted in the intra prediction mode.

The block above does not exist. For example, the current block is a coding block located at the top edge of the frame.

When the encoder or decoder supports parallel processing, the block on top may be considered non-existent (or inaccessible) when it is located in a tile other than the tile where the current block is, i.e. this current encoding block is located at the top edge of the tile.

In another example, when the encoder or decoder does not support parallel processing, the top block may be considered available when it is in different tiles from the current block, i. the current coding block is located at the top edge of the tile.

When the encoder or decoder supports parallel processing, the top block may be considered non-existent when it and the current block are in different slices, i.e. the current coding block is located at the top edge of the slice.

In another example, when the encoder or decoder does not support parallel processing, the top block may be considered available when it is located in different slices from the current block, i.e. the current coding block is located at the top edge of the slice.

When it is necessary to limit the size of the line buffer in the encoder or decoder, the block above can be considered non-existent when it is located in a different CTU relative to the current block, i.e. this current coding unit is located at the top edge of the current CTU.

In one example, when the decoder side or the encoder side supports a line buffer size limit, then the top block that resides in a CTU other than the CTU where the current block resides is considered non-existent. When the line buffer size limit is not supported, then the block is considered to exist.

The opposite case (ie, the block on the left is available) contains the intra prediction mode relative to the block on top in the 6-entry MPM mode list.

It is checked whether the planar (PLANAR_IDX=0) mode has been inserted into the MPM mode list, (i.e., it is checked whether any of the intra prediction modes relative to the block on the left or the block on top is a planar mode), only if the planar mode has not been inserted in list of MPM modes, then insert the planar mode into the list of MPM modes. It is checked whether the DC mode (DC_IDX=1) has been entered into the MPM mode list, (i.e., it is checked whether any of the intra prediction modes with respect to the block on the left or the block on top is the DC mode), only if the DC mode is not was inserted into the MPM mode list, then insert this DC mode into the MPM mode list.

When a block on the left is available and when the intra prediction mode with respect to that block is angular mode, i.e. (the mode with index > DC_IDX, and it can be called the corner of the prediction mode with respect to the block on the left (the mode with the index angularLeft)), get the indices of the two corner modes closest to it by calculating the indices of angularLeft-1, angularLeft+1. Note that a -1 or +1 shift adding operation can contain an up or down circle operation, for example,

When the mode's angularLeft index is 2, then the angularLeft-1 index will be 66 (circle up operation), or when the mode's angularLeft index is 66, then the angularLeft+1 index will be 2 (circle down operation).

When a prediction mode with index angularLeft-1 has not been inserted into the MPM mode list, it is inserted into this MPM mode list.

When the prediction mode with index angularLeft+1 has not been inserted into the MPM mode list, it is inserted into this MPM mode list.

When the MPM mode list is empty, and when a block from above is available, and when the intra prediction mode with respect to this block is an angle mode, i.e. (mode index > DC_IDX, it can be called the angular mode of prediction relative to the block above (mode with index angularAbove)), get the indices of the two angular modes closest to it by calculating the indices of angularAbove-1, angularAbove+1. Note that an add shift operation of -1 or +1 may contain an up or down circle operation, in one example, when the mode's angularLeft index is 2, then the mode's angularLeft-1 index will be 66 (the circle up operation), or when the mode's angularLeft index is 66, then the mode's angularLeft+1 index will be 2 (circle down operation).

When a prediction mode with index angularAbove-1 has not been inserted into the list of MPM modes, it is inserted into this list of MPM modes.

If the MPM mode list is empty (eg, the number of intra prediction modes in the MPM mode list is less than 6) and if the prediction mode with index angularAbove+1 has not been inserted into the MPM mode list, it is inserted into the MPM mode list.

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

vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode 2 (index 2), vertical diagonal mode (VDIA_IDX index), or diagonal mode (DIA_IDX index).

Brief summary of variations of the proposed method:

The accessibility of the block on the left must take into account both factors - whether parallel processing is supported or not.

The accessibility of a block from above must take into account both factors - whether parallel processing is supported or not.

To get the two nearest modes relative to the block on the left or relative to the block above, you can also add +1 first to the main mode index, and then -1.

The last candidate for the list of MPM modes may have the index VIDA_IDX or DIA_IDX.

Insertion can also be done in the following order - left mode, top mode, planar mode, DC mode, and default modes (modes with indices VER_IDX, HOR_IDX, 2, VDIA_IDX or DIA_IDX).

Truncated unary binarization is used to signal the index mpm_idx. The first three mpm_idx index packets may use three different independent contexts, or all mpm_idx index packets are encoded using context-adaptive binary arithmetic coding (CABAC).

In one example, a procedure for deriving the intra prediction mode for the luminance component is proposed.

The input to this procedure is the following:

luminance position (xCb , yCb) specifying the top-left sample of the current luminance coding block relative to the top-left sample of the current picture,

variable cbWidth specifying the width of the current coding block in luma samples,

variable cbHeight specifying the height of the current encoding block in luma counts.

In this procedure, the intraprediction mode IntraPredModeY[ xCb ][ yCb ] of the luminance component is obtained.

Table 2 specifies the intraprediction mode index value IntraPredModeY[ xCb ][ yCb ] and associated names.

Table 2. Intra prediction mode specification and associated names

Intra prediction mode Associated name 0 INTRA_PLANAR one INTRA_DC 2..66 INTRA_ANGULAR2..INTRA_ANGULAR66 77 INTRA_CCLM

Note: The INTRA_CCLM intra prediction mode is only applicable to chroma.

The IntraPredModeY[ xCb ][ yCb ] mode is determined through the following ordered steps:

The adjacent positions ( xNbA, yNbA ) and ( xNbB, yNbB ) are assigned coordinates (xCb − 1, yCb + cbHeight - 1) and ( xCb + cbWidth - 1, yCb − 1 ), respectively.

In the case of replacing X with A or B, the variables candIntraPredModeX and addModeX are obtained as follows:

The accessibility derivation procedure for a block, as specified in clause 6.4.X of [Ed. (BB): Neighboring blocks availability checking process tbd] is invoked such that as input, positions (xCurr, yCurr) are assigned coordinates (xCb, yCb) and neighbor position (xNbY, yNbY) are assigned coordinates ( xNbX, yNbX), and assign the output variable availableX.

The candidate intra prediction modes candIntraPredModeX and addModeX are obtained as follows:

When one or more of the following conditions are true (satisfied), the value of candIntraPredModeX is set to a value other than the range 0 to 66 (eg, a value of -1), inclusive, and the parameter addModeX is set to FALSE (false).

The availableX variable is FALSE.

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

X is equal to B and yCb − 1 is less than ( ( yCb >> CtbLog2SizeY ) << CtbLog2SizeY ).

Otherwise, the candIntraPredModeX parameter is set to IntraPredModeY[ xNbX ][ yNbX ] and the addModeX parameter is set to TRUE. The variable mIdx is set equal to 0. The parameter candModeList[ x ] with x = 0..5 is obtained as follows:

The found mode is an angular mode when and only when its index is between 2 and 66, inclusive.

When one of candIntraPredModeA and candIntraPredModeB is angular mode, the following applies:

candModeList[ 0 ] = INTRA_PLANAR

candModeList[ 1 ] = INTRA_DC

candModeList[ 2 ] = INTRA_ANGULAR50

candModeList[ 3 ] = INTRA_ANGULAR18

candModeList[ 4 ] = INTRA_ANGULAR46

candModeList[ 5 ] = INTRA_ANGULAR54

Otherwise (at least one of candIntraPredModeA and candIntraPredModeB is an angular mode).

When the addModeA parameter is TRUE, the candModeList [ mIdx ] parameter is set to candIntraPredModeA and the mIdx index is incremented by 1.

When addModeB is TRUE and mIdx is 0, candModeList[ mIdx] is set to candIntraPredModeB and mIdx is incremented by 1.

When addModeB is TRUE and mIdx is 1 and candIntraPredModeB is not equal to candModeList[0], candModeList[ mIdx] is set to candIntraPredModeB and mIdx is incremented by 1.

When the INTRA_PLANAR parameter is not equal to candModeList [ i ] for any i=0.. mIdx − 1, the modeList[ mIdx ] parameter is set to INTRA_PLANAR and the mIdx index is incremented by 1.

When the INTRA_DC parameter is not equal to candModeList [ i ] for any i=0.. mIdx − 1, the modeList[ mIdx ] parameter is set to INTRA_DC and the mIdx index is incremented by 1.

When both candIntraPredModeA and candIntraPredModeB are between mode indices 2 and 66 and candIntraPredModeA is not equal to candIntraPredModeB,

Set the angMinus variable to 2 + ( (candIntraPredModeA + 62 ) % 65 )

Set the angPlus variable to 2 + ( (candIntraPredModeA - 1 ) % 65 ).

When the parameter candIntraPredModeB is equal to angMinus then

the parameter candModeList [ mIdx ] is set to 2 + ( (candIntraPredModeB+ 62 ) % 65 ) and the mIdx index is incremented by 1.

parameter candModeList [ mIdx ] is set equal to angPlus.

Otherwise, the parameter (candIntraPredModeB is not equal to angMinus)

the parameter candModeList [ mIdx ] is set to angMinus and the index mIdx is incremented by 1.

When the candIntraPredModeB parameter is angPlus, the candModeList [ mIdx ] parameter is set to 2 + ( (candIntraPredModeB-1 ) % 65 )

Otherwise, the parameter (candIntraPredModeB is not equal to angPlus), the parameter candModeList [ mIdx ] is set to angPlus

Otherwise (only candIntraPredModeA is between mode indices 2 and 66, or only candIntraPredModeB is between mode indices 2 and 66, or candIntraPredModeA is equal to candIntraPredModeB and they are all between mode indices 2 and 66)

When the parameter candIntraPredModeA is greater than mode index 2, the Angular variable is set to candIntraPredModeA

Otherwise (candIntraPredModeA is not greater than mode index 2), the Angular variable is set to candIntraPredModeB

When the Angular variable is between mode indexes 49 and 51 inclusive, the finalMode variable is set to 18.

Otherwise (the Angular variable is not between mode indexes 49 and 51, inclusive), the finalMode variable is set to 50.

The candModeList [ mIdx ] parameter is set to 2 + ( (Angular + 62 ) % 65 ) and the mIdx index is incremented by 1.

The candModeList [ mIdx ] parameter is set to 2 + ( (Angular - 1 ) % 65 ) and the mIdx index is incremented by 1.

The parameter candModeList [ mIdx ] is set to finalMode.

The parameter IntraPredModeY[ xCb ][ yCb ] is obtained through the following procedure:

When the intra_luma_mpm_flag[ xCb ][ yCb ] parameter is 1, the IntraPredModeY[ xCb ][ yCb ] parameter is set to candModeList[ intra_luma_mpm_idx[ xCb ][ yCb ] ].

Otherwise, the parameter IntraPredModeY[ xCb ][ yCb ] is obtained as a result of the following ordered steps:

The array candModeList[ x ], x = 0..5 is modified through the following ordered steps:

For i consecutively equal from 0 to 4, inclusive, apply:

For j sequentially equal to i+1 to 5, inclusive, compare the parameter candModeList[ i ] with candModeList [ j ],

When the parameter candModeList[ i ] is greater than candModeList[ j ], both values are exchanged as follows:

(candModeList[ i ], candModeList[ j ] ) = Swap( candModeList[ i ], candModeList[ j ] )

The IntraPredModeY[ xCb ][ yCb ] parameter is obtained from the following ordered steps:

The parameter IntraPredModeY[ xCb ][ yCb ] is set to intra_luma_mpm_remainder[ xCb ][ yCb ].

For i equal to 0 to 5, inclusive, when the parameter IntraPredModeY[ xCb ][ yCb ] is not less than candModeList[ i ], the value of the parameter IntraPredModeY[ xCb ][ yCb ] is increased by one.

The variable IntraPredModeY[ x ][ y ] with x = xCb..xCb + cbWidth − 1 and y = yCb..yCb + cbHeight − 1 is set equal to IntraPredModeY[ xCb ][ yCb ].

The present invention aims to improve the intra prediction mode signaling scheme. The present invention provides a video decoding method and a video decoding apparatus.

In FIG. 7 shows an example of 67 intra prediction modes, for example, as proposed for VVC coding, the set of intra prediction modes of 67 intra prediction modes contains: planar mode (index 0), dc mode (index 1), and angular modes with indices 2 to 66, where the lower left corner mode of FIG. 7 has index 2 and the index numbering is incremented until index 66 is reached, which corresponds to the upper right corner mode shown in FIG. 7.

According to another aspect of the present invention, a decoding device is provided, comprising a processor circuit configured to implement the decoding methods described above.

According to another aspect of the present invention, there is provided a computer program product comprising program code for performing the decoding methods described above.

According to another aspect of the present invention, a decoder for decoding video data is provided, the decoder comprising: one or more processors; and a non-volatile 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 a decoder to perform the decoding methods described above.

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

According to another aspect of the present invention, a coding method is provided, comprising: deriving one intra prediction mode for an image block from a plurality of multiple intra prediction modes, this plurality of intra prediction modes for the image block comprising a plurality of most likely modes, MPM, and a plurality of non-MPM modes, where this set of non-MPM modes contains a first set of intra prediction modes and a second set of intra prediction modes; if the intra prediction mode is included in the plurality of non-MPM modes, generating a mapping relationship between at least one intra prediction mode of the first plurality of intra prediction modes and at least one intra prediction mode of the plurality of non-MPM modes; encoding this intra prediction mode for the image block to obtain a codeword regarding the intra prediction mode in accordance with the display ratio.

In one form of implementation of the present application, the procedure for obtaining an intra prediction mode for an image block may refer to the relevant fragments of the following detailed description of part of the embodiments of the invention and to the relevant points in the field of video coding technology, such as ITU-T H.264, ITU- T H.265.

In one embodiment of the present application, the encoding method further comprises: generating a set of MPM modes and determining whether the considered intra prediction mode for an image block is included in the set of MPM modes. Therefore, when the intra prediction mode for the image block is not included in the set of MPM modes, then that intra prediction mode for the image block is included in the set of non-MPM modes.

The procedure for generating a plurality of MPM modes may refer to relevant passages in the description of the invention or relevant points in the field of video coding technology such as ITU-T H.264, ITU-T H.265 standards.

In one form of implementation of the present application, the procedure for generating a mapping relationship between at least one intra prediction mode of the first set of intra prediction modes and at least one intra prediction mode of the set of non-MPM modes may refer to the corresponding description on the decoding side.

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

According to another aspect of the present invention, an encoder is provided, comprising a processor circuit configured to implement the encoding methods described above.

According to another aspect of the present invention, there is provided a computer program product comprising program code for performing the encoding methods described above.

According to another aspect of the present invention, an encoder for encoding video data is provided, wherein the encoder comprises: one or more processors; and a non-volatile 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 an encoder to implement the encoding methods described above.

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

Option 1. A method for constructing a list of the most probable modes (Most Probable Mode, MPM) for internal prediction, the method contains:

determining whether a block to the left (for example, block L in FIG. 5) is available from the current coding block or not (for example, if there is no intra prediction mode relative to the block to the left, then this block to the left is not available, and if there is an intra prediction mode relative to the block to the left, then this block on the left is available);

determining whether a block from above (for example, block A in Fig. 5) is available from the current coding block or not (for example, if there is no intra prediction mode relative to the block above, then this block from above is not available, and if there is an intra prediction mode relative to the block above, then this block is accessible from above);

using planar mode, DC mode, vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode corresponding to this vertical mode with offset -4, intra prediction mode corresponding to this vertical mode with offset 4 (for example, list MPM modes has the form (0, 1, 50, 18, 46, 54), index value 0 corresponds to planar mode, index value 1 corresponds to DC mode, index value 50 corresponds to vertical mode, index value 18 corresponds to horizontal mode, index value 46 corresponds to the intra prediction mode corresponding to the vertical mode with a shift of -4, the index value of 54 corresponds to the intra prediction mode corresponding to the vertical mode with a shift of 4),

when one of the following conditions is satisfied:

the block to the left of the current coding block is not available and the block above the current coding block is not available;

the block to the left of the current coding block is unavailable, the block above the current coding block is available, and the intra prediction mode relative to the block above is a planar mode;

the block to the left of the current coding block is unavailable, the block above the current coding block is available, and the intra prediction mode relative to the block above is the DC mode;

the block to the left of the current coding block is available, the block above the current coding block is unavailable, and the intra prediction mode relative to the block to the left is planar mode;

the block to the left of the current coding block is available, the block upstream of the current coding block is unavailable, and the intra prediction mode relative to the block to the left is a planar DC mode;

the block to the left of the current coding block is available, the block upstream of the current coding block is available, and the block-to-left intra-prediction mode is not an angular mode (i.e., the block-to-left intra-prediction mode is planar mode or DC mode), and top block prediction mode is not an angular mode (ie, block top intra prediction mode is planar mode or DC mode).

Option 2. A method for constructing a list of the most probable modes, MPM, for intra prediction, the method contains:

determining whether a block to the left (for example, block L in FIG. 5) is available from the current coding block or not (for example, if there is no intra prediction mode relative to the block to the left, then this block to the left is not available, and if there is an intra prediction mode relative to the block to the left, then this block on the left is available, and if the block on the left is available, get the intra prediction mode with respect to this block from above);

when the left block is available (for example, the left block intra prediction mode is the corner mode, which means that the index value corresponding to this left block intra prediction mode is not less than 2, the range of these index values can be from 2 to 66; the index value , corresponding to this left block intra prediction mode is 0 (planar mode) or 1 (DC mode)), adding the left block intra prediction mode to the MPM mode list (for example, the original MPM mode list is an empty list, and on this step add the considered intra prediction mode relative to the block on the left in the list of MPM modes).

Option 3. A method for constructing a list of the most probable modes, MPM, for intra prediction, the method contains:

determining whether a block from above (for example, block A in Fig. 5) is available from the current coding block or not (for example, if there is no intra prediction mode relative to the block above, then this block from above is not available, and if there is an intra prediction mode relative to the block above, then this top block is available, and if the top block is available, get the intra prediction mode relative to that top);

when block top is available (for example, block top intra prediction mode is corner mode, which means that the index value corresponding to this top block intra prediction mode is not less than 2, the range of these index values can be from 2 to 66, this value index value may also be 66; or the index value corresponding to this block-up intra prediction mode is 0 (planar mode) or 1 (DC mode)), and the considered block-up intra prediction mode is not included in the list of MPM modes, adding block-upward intra prediction mode to the MPM mode list (e.g., the initial MPM mode list is an empty list, and at this step, the considered block-upward intra prediction mode is added to the MPM mode list; or this MPM mode list contains the intra-block prediction mode on the left, and looking received block-up intra prediction mode is different from the specified block-up intra prediction mode, so that the considered block-up intra prediction mode is added to the MPM mode list, there are two intra prediction modes in the MPM mode list (one index value corresponds to the intra prediction mode with respect to block on the left and one index value corresponds to the intra prediction mode relative to the block above)).

Option 4. The method according to option 2 or 3, where this method further comprises:

when the block on the left is not available, or the intra prediction mode with respect to the left block is not an angular mode (for example, there is no intra prediction mode with respect to the left block, or the intra prediction mode with respect to the left block is a planar mode, or the intra prediction mode with respect to the left block is a DC mode ), and the block-up intra prediction mode is the angle mode (for example, the index value corresponding to the block-up intra prediction mode is not less than 2, the range of index values may be 2 to 66, this index value may also be 66),

and if the upper block intra prediction mode is not in the MPM mode list, adding the upper block intra prediction mode to the MPM mode list (in one example, if the initial MPM mode list is an empty list, or only contains no angle modes if the block left not available or block-up intra prediction mode is not an angle mode, adding the considered block-up intra prediction mode to the MPM mode list Since, in this situation, the block-up intra prediction mode is clearly not included in the MPM mode list, there is no need to determine, whether this intra-prediction mode with respect to the block above is included in the list of MPM modes or not).

Option 5. The method according to option 4, where this method further comprises:

if the planar mode is not included in the MPM mode list, adding the planar mode to the MPM mode list (in one example, after adding the top block intra prediction mode in question to the MPM mode list, determining whether to add the planar mode to the MPM mode list or not ).

Option 6. The method according to option 4 or 5, where this method further comprises:

if the DC mode is not in the MPM mode list, adding the DC mode to the MPM mode list MPM or Not In another example, after determining whether the planar mode should be added to the MPM mode list or not, then it is determined whether the DC mode should be added to the MPM mode list or not).

Option 7. The method according to any one of options 4 - 6, where this method further comprises:

adding an offset to the block-up prediction mode index to obtain an index of the block-up offset prediction mode, if the block-up offset prediction mode is not in the MPM mode list, adding this block-up offset prediction mode to the MPM mode list (in one of examples, this step may be performed after adding the block-upward intra prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add the planar mode to the MPM mode list or not.In another example, this step can be executed after determining whether the DC mode should be added to the MPM mode list or not).

Option 8. The method according to option 7, where the shift value is -1.

Embodiment 9 The method of Embodiment 7 wherein the shift amount is 1 (in one example, two shift amounts are added to a block-up prediction mode index to obtain a block-up offset prediction mode index and another block-up offset prediction mode index, if offset (offset equal to -1) block-up prediction mode is not in the MPM mode list, adding the specified offset block-up prediction mode to the MPM mode list, and if another offset (offset is 1) block-up prediction mode is not included in the list MPM modes, adding this block-offset prediction mode from above to the list of MPM modes).

Option 10. The method according to any one of options 4 - 9, where this method further comprises:

if the vertical mode is not in the MPM mode list, adding the vertical mode to the MPM mode list (in one example, this step may be performed after adding the block-upward intra prediction mode to the MPM mode list. In another example, this step may be performed after determining whether the planar mode should be added to the MPM mode list or not.In another example, this step may be performed after determining whether the DC mode should be added to the MPM mode list or not.In another example, this step may be performed after determining whether to add a block-up-offset prediction mode to the list of MPM modes.)

Option 11. The method according to any one of options 4 - 10, where this method further comprises:

if the horizontal mode is not in the MPM mode list, adding the horizontal mode to the MPM mode list (in one example, this step may be performed after adding the block-upward intra prediction mode to the MPM mode list. In another example, this step may be performed after determining whether the planar mode should be added to the MPM mode list or not.In another example, this step may be performed after determining whether the DC mode should be added to the MPM mode list or not.In another example, this step may be performed after determining whether a block-up-offset prediction mode should be added to the MPM mode list.In another example, this step may be performed after determining whether the vertical mode should be added to the MPM mode list.)

Option 12. The method according to any one of options 4 - 10, where this method further comprises:

when the horizontal mode is not in the MPM mode list and when the number of intra prediction modes in the MPM mode list is less than a threshold value (e.g., the threshold value is 6), adding the horizontal mode to the MPM mode list (in one example, this step may be performed after adding intra block top prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether to whether to add the DC mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add the upper block offset prediction mode to the MPM mode list.In another example, this step may be performed after determining whether or add vertical mode to the MPM mode list.)

Option 13. The method according to option 2 or 3, where this method further comprises:

when block-up intra prediction mode is not available or when block-up intra prediction mode is not angular mode (e.g., no block-up intra prediction mode, or block-up intra prediction mode is planar mode, or block-up intra prediction mode is DC mode ) and the left block intra prediction mode is the angle mode (for example, the index value corresponding to the left block intra prediction mode is not less than 2, the range of index values may be 2 to 66, this index value may be 66),

and if the left block intra prediction mode is not in the MPM mode list, adding the left block intra prediction mode to the MPM mode list (in some examples, since the left block intra prediction mode is an angular mode, it will be added to the MPM mode list, in this example, it is not necessary to determine whether the left block intra prediction mode is included in the MPM mode list or not.)

Option 14. The method according to option 13, where this method further comprises:

when a planar mode is not in the MPM mode list, adding that planar mode to the MPM mode list (in one example, after adding the left block intra prediction mode in question to the MPM mode list, to determine whether to add the planar mode to the MPM mode list or not).

Option 15. The method according to option 13 or 14, where this method further comprises:

when the DC mode is not included in the MPM mode list, adding the DC mode to the MPM mode list or No. In another example, after determining whether the planar mode should be added to the MPM mode list or not, then it is determined whether the DC mode should be added to the MPM mode list or not).

Option 16. The method according to any one of options 13-15, where this method further comprises:

adding an offset to the left block prediction mode index to obtain a left block offset prediction mode if that left block offset prediction mode is not in the MPM mode list, adding the left block offset prediction mode to the MPM mode list (in one of examples, this step may be performed after adding the block-left intra prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add the planar mode to the MPM mode list or not.In another example, this step can be executed after determining whether DC mode should be added to the MPM mode list or not.)

Option 17. The method according to option 16, where the shift value is -1.

Embodiment 18 The method of Embodiment 16 wherein the shift amount is 1 (in one example, two shifts are added to the left block prediction mode index to obtain one left block offset prediction mode and another left block offset prediction mode if said one left block offset prediction mode (shift value is -1) is not in the MPM mode list, adding this left block offset prediction mode to the MPM mode list, and if the specified other block left offset prediction mode (shift value is 1) is not enters the list of MPM modes, adding this other block-offset prediction mode to the left of the list of MPM modes.)

Option 19. The method according to any one of options 13 - 18, where this method further comprises:

if the vertical mode is not in the MPM mode list, adding that vertical mode to the MPM mode list (In one example, this step may be performed after adding the left block intra prediction mode to the MPM mode list. In another example, this step may be executed after determining whether to add the planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add the DC mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add a block-offset prediction mode on the left to the list of MPM modes).

Option 20. The method according to any one of options 13 - 19, where this method further comprises:

when the horizontal mode is not in the MPM mode list, adding that horizontal mode to the MPM mode list (In one example, this step may be performed after adding the intra prediction mode for the block on the left to the MPM mode list. In another example, this step may be executed after determining whether to add planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether DC mode should be added to the MPM mode list or not.In another example, this step may be performed after determining whether to add a block-offset prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add the vertical mode to the MPM mode list).

Option 21. The method according to any one of options 13-19, where this method further comprises:

when the horizontal mode is not in the MPM mode list and when the number of intra prediction modes in the MPM mode list is less than a threshold value (e.g., the threshold value is 6), adding the horizontal mode to the MPM mode list (in one example, this step may be performed after adding an intra block-relative prediction mode to the left MPM mode list.In another example, this step may be performed after determining whether to add a planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether to whether to add the DC mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add the left block offset prediction mode to the MPM mode list.In another example, this step may be performed after determining whether or add vertical mode to the MPM mode list).

Option 22. The method according to option 2, where this method further comprises:

determining whether a block from above (for example, block A in FIG. 5) is available from the current coding block or not (for example, if there is no intra prediction mode relative to the block above, the block above is not available, if there is an intra prediction mode relative to the block above, this block is above available);

when the block-up intra prediction mode is an angular mode (for example, the index value corresponding to the block-up intra prediction mode is not less than 2, the range of index values may be from 2 to 66, this index value may also be 66) and when the intra block-up mode top block prediction is included in the list of MPM modes (for example, top block intra prediction mode is the same as left block intra prediction mode),

when the planar mode is not in the MPM mode list, adding the planar mode to the MPM mode list (in one example, since the left block intra prediction mode and the top block intra prediction mode are corner modes, then add the planar mode to the MPM mode list) .

Option 23. The method according to option 22, where this method further comprises:

when the DC mode is not included in the MPM mode list, adding the DC mode to the MPM mode list (In another example, after determining whether to add the planar mode to the MPM mode list or not, it is determined whether to add the DC mode to the MPM or not In one example, since the left block intra prediction mode and the top block intra prediction mode are angular modes, then DC mode is added to the list of MPM modes.)

Option 24. The method according to option 22 or 23, where this method further comprises:

adding an offset to the left block prediction mode index to obtain the left block offset mode index if that left block offset prediction mode is not in the MPM list, adding that left block offset prediction mode to the MPM mode list (in one example , this step may be performed after adding the left block intra prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add the planar mode to the MPM mode list or not.In another example, this step may be executed after determining whether the DC mode should be added to the MPM mode list or not).

Embodiment 25 The method of Embodiment 24 wherein the offset value is -1.

Embodiment 26 The method of Embodiment 24 wherein the shift amount is 1 (in one example, two shifts are added to the left block prediction mode index to obtain one left block offset prediction mode and another left block offset prediction mode when one left block offset prediction mode (shift amount -1) is not included in the MPM mode list, add this left block offset prediction mode to the MPM mode list, and when another block left offset prediction mode (shift amount is 1) is not included to the MPM mode list, add this other block-offset prediction mode to the left of the MPM mode list).

Option 27. The method according to any one of options 22-26, where this method further comprises:

when the vertical mode is not in the MPM mode list, adding that vertical mode to the MPM mode list (In one example, this step may be performed after adding the left block intra prediction mode to the MPM mode list. In another example, this step may be executed after determining whether to add the planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add the DC mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add a block-offset prediction mode on the left to the list of MPM modes).

Option 28. The method according to any one of options 22-27, where this method further comprises:

when the horizontal mode is not included in the MPM mode list, adding that horizontal mode to the MPM mode list (In one example, this step may be performed after adding the left block intra prediction mode to the MPM mode list. In another example, this step may be executed after determining whether to add the planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add the DC mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add left-block offset prediction mode to the MPM mode list (In another example, this step may be performed after determining whether to add the vertical mode to the MPM mode list).

Option 29. The method according to any one of options 22-27, where this method further comprises:

when the horizontal mode is not in the MPM mode list and when the number of intra prediction modes in the MPM mode list is less than a threshold value (e.g., the threshold value is 6), adding this horizontal mode to the MPM mode list (in one example, this step may be performed after adding the left block intra prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add the planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether whether to add the DC mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add the left block offset prediction mode to the MPM mode list.In another example, this step may be performed after determining whether whether vertical mode should be added to the MPM mode list.)

Option 30. The method according to option 2, where this method further comprises:

determining whether a block from above (for example, block A in FIG. 5) is available from the current coding block or not (for example, if there is no intra prediction mode relative to the block above, this block from above is not available, if there is an intra prediction mode relative to the block above, this block top available);

when the upper block intra prediction mode is an angle mode, the left block intra prediction mode is an angular mode (for example, the index value corresponding to the upper block intra prediction mode is not less than 2, the range of index values can be from 2 to 66, this the index value can also be 66) and the block-up intra prediction mode is not included in the MPM mode list (for example, the block-up intra-prediction mode is different from the block-up intra prediction mode),

adding block-up intra prediction mode to the MPM mode list (for example, the MPM mode list contains left block intra prediction mode, and block-up intra prediction mode is different from block-up intra prediction mode, so block-up intra prediction mode is added to a list of MPM modes, so that there are two intra prediction modes (an intra prediction mode corresponding to the left block and an intra prediction mode corresponding to the top block) in the MPM mode list.

Embodiment 31. The method of Embodiment 30, wherein the method further comprises:

when the planar mode is not included in the MPM mode list, adding that planar mode to the MPM mode list (in one example, after adding the top block intra prediction mode to the MPM mode list, determining whether to add the planar mode to the MPM mode list or not ; in another example, since both left block intra prediction mode and block top intra prediction mode are angular modes, this step adds the planar mode to the list of MPM modes.)

Option 32. The method according to options 30 and 31, where this method further comprises:

when the DC mode is not in the MPM mode list, adding the DC mode to the MPM mode list (in one example, after adding the block-relative intra prediction mode on top of the MPM modes, determining whether to add the DC mode to the MPM mode list or not In another example, after determining whether to add the planar mode to the MPM mode list or not, it is determined whether to add the DC mode to the MPM mode list or not, in another example, since both modes are left block intra prediction mode and intra-prediction mode with respect to the top block are angle modes, at this point, add DC mode to the MPM mode list.)

Option 33. The method according to any one of options 30-32, where this method further comprises:

adding a shift amount (eg, -1) to a left block prediction mode index to obtain a left block offset prediction mode index when the left block offset prediction mode is in the MPM mode list, adding a shift amount (eg, -1) to block-up prediction mode index to obtain a block-up offset prediction mode index, adding this block-up offset prediction mode to the MPM mode list.

Option 34. The method according to any one of options 30-33, where this method further comprises:

adding a shift amount (e.g., -1) to the left block prediction mode index to obtain the left block shifted prediction mode index when the left block shifted prediction mode is not in the MPM list, adding this left block prediction mode offset to list of MPM modes.

Option 35. The method according to any one of options 30-34, where this method further comprises:

adding a shift amount (eg, -1) to the left block prediction mode index to obtain a left block offset prediction mode index, adding another offset value (eg, 1) to the left block prediction mode index to obtain another offset mode index left block prediction mode when one left block offset prediction mode is included in the MPM mode list; adding another left block offset prediction mode to the MPM mode list.

Option 36. The method according to any one of options 30-34, where this method further comprises:

adding a shift value (e.g., -1) to the left block prediction mode index to obtain the index of one left block prediction mode offset if the left block offset prediction mode is in the MPM mode list, adding another shift value (e.g., 1) to the left block prediction mode index to obtain the index of the other left block offset prediction mode, adding the other left block offset prediction mode to the MPM mode list.

Option 37. The method according to any one of options 30-32, where this method further comprises:

adding a shift amount (e.g., -1) to a left block prediction mode index to obtain an index of one left block offset prediction mode when that left block prediction mode offset is included in the MPM mode list, adding a shift amount (e.g., -1) to a block-up prediction mode index to obtain a block-up offset prediction mode index, adding this block-up offset prediction mode to the MPM mode list;

adding a different offset value (eg, 1) to the left block prediction mode index to obtain an index of another left block offset prediction mode, adding that other left block offset prediction mode to the MPM mode list.

Option 38. The method according to option 34, where this method further comprises:

adding a different offset value (e.g., 1) to the left block prediction mode index to obtain another left block offset prediction mode if that other left block offset prediction mode is not in the MPM mode list, adding that other left block offset prediction mode block on the left to the MPM mode list.

Option 39. The method according to option 34 or 38, where this method further comprises:

adding another offset value (eg, 1) to the left block prediction mode index to obtain another left block offset prediction mode when that other left block offset prediction mode is included in the MPM mode list,

adding a different offset value (e.g., 1) to the block-up prediction mode index to obtain another block-up prediction mode offset index, adding that other block-up prediction mode offset index to the MPM mode list.

Option 40. The method according to option 2, where this method further comprises:

determining whether a block from above (for example, block A in FIG. 5) is available from the current coding block or not (for example, if there is no intra prediction mode relative to the block above, the block above is unavailable, when there is an intra prediction mode relative to the block above, this block is from above is available, and if the top block is available, get the intra prediction mode relative to the top block);

when block-above is not available, or when block-above intra prediction mode is not angular mode (e.g., no block-above intra prediction mode, or block-above intra prediction mode is planar mode, or block-above intra prediction mode is DC mode) and the left block intra prediction mode is the corner mode (for example, the index value corresponding to the left block intra prediction mode is not less than 2, the index value range may be 2 to 66, the index value may also be 66),

when the planar mode is not included in the MPM mode list, adding that planar mode to the MPM mode list (in one example, after adding the left block intra prediction mode to the MPM mode list, determine whether to add the planar mode to the MPM mode list or not ).

Embodiment 41. The method of Embodiment 40, wherein the method further comprises:

when the DC mode is not included in the MPM mode list, adding this DC mode to the MPM mode list MPM or Not In another example, after determining whether the planar mode should be added to the MPM mode list or not, it is determined whether the DC mode should be added to the MPM mode list or not).

Option 42. The method according to option 40 or 41, where this method further comprises:

Adding a shift amount to the Left Block Prediction Mode Index to obtain the Left Block Offset Prediction Mode Index, if that Left Block Offset Prediction Mode is not in the MPM Mode List, Adding this Left Block Offset Prediction Mode to the MPM Mode List (in In one example, this step may be performed after adding the left block intra prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add the planar mode to the MPM mode list.In another example, this step can be performed after determining whether DC mode should be added to the MPM mode list or not.)

Embodiment 43. The method according to Embodiment 42, where the offset value is -1.

Embodiment 44. The method of Embodiment 42 wherein the offset value is 1 (in one example, two offset values are added to a prediction mode index relative to the block on the left to obtain an index of one offset prediction mode relative to the left block and an index of another offset prediction mode relative to the left block , if the specified one left block offset prediction mode (offset value is -1) is not in the MPM mode list, adding that one left block offset prediction mode to the MPM mode list, and if the specified other left block offset prediction mode (value shift equals 1) not in the MPM mode list, adding this other block-biased prediction mode to the left of the MPM mode list.)

Embodiment 45. The method of any one of embodiments 40-44, wherein the method further comprises:

when the vertical mode is not in the MPM mode list, adding that vertical mode to the MPM mode list (In one example, this step may be performed after adding the left block intra prediction mode to the MPM mode list. In another example, this step may be executed after determining whether to add the planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add the DC mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add a block-offset prediction mode on the left to the list of MPM modes.)

Embodiment 46. The method of any one of Embodiments 40-45, wherein the method further comprises:

when the horizontal mode is not included in the MPM mode list, adding the horizontal mode to the MPM mode list (in one example, this step may be performed after adding the left block intra prediction mode to the MPM mode list. In another example, this step may be performed after determining whether the planar mode should be added to the MPM mode list or not.In another example, this step may be performed after determining whether the DC mode should be added to the MPM mode list or not.In another example, this step may be performed after determining whether to add left-block offset prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add the vertical mode to the MPM mode list.)

Option 47. The method according to any one of options 40-46, where this method further comprises:

when the horizontal mode is not in the MPM mode list and the number of intra prediction modes in the MPM mode list is less than a threshold (e.g., the threshold is 6), adding the horizontal mode to the MPM mode list (in one example, this step may be performed after adding block-left intra prediction mode to the MPM mode list.In another example, this step may be performed after determining whether to add a planar mode to the MPM mode list or not.In another example, this step may be performed after determining whether to add DC mode in the MPM mode list or not.In another example, this step may be performed after determining whether to add a left block offset prediction mode to the MPM mode list.In another example, this step may be performed after determining whether add vertical mode to MPM mode list).

Option 48. An encoder containing a processor circuit for implementing the method according to any one of options 1 - 47.

Option 49. A decoding device containing a processor circuit for implementing the method according to any one of options 1 to 47.

Option 50. A computer program product containing program code for implementing the method according to any one of options 1 - 47.

Option 51. A decoder for building a list of the most probable modes, MPM, containing:

one or more processors; and

a non-volatile computer-readable storage medium connected to said processors and storing programs for execution by the processors, where these programs, when executed by the processors, configure a decoder to implement the method according to any one of options 1 to 47.

Option 52. Encoder for building a list of the most probable modes, MPM, containing:

one or more processors; and

a non-volatile computer-readable storage medium connected to said processors and storing programs for execution by the processors, where these programs, when executed by the processors, configure an encoder to implement the method according to any one of options 1-47.

To calculate the values of the weight coefficients necessary for predicting pixels within the considered block, a piecewise linear approximation is introduced. Such a piecewise linear approximation, on the one hand, significantly reduces the computational complexity of the distance-weighted prediction mechanism compared to the direct calculation of weight coefficients, and, on the other hand, helps to achieve higher accuracy of weight coefficient values compared to previously used simplifications.

These variations can be applied to other bidirectional and position-dependent intra prediction technologies (e.g., various modifications of the position-dependent intra-prediction combination (PDPC) method), as well as to mechanisms that use weights depending on the distance from one pixel to another, for the purpose of blending different parts of a picture (image) (for example, some blending methods in image processing).

Various embodiments of the subject matter of the present invention and the operations described herein may be implemented in digital electronic circuitry or by computer downloadable software, firmware or hardware, including the structures discussed herein and their structural equivalents, or using combinations of the above items. Various embodiments of the subject matter of the present invention may be implemented by one or more computer programs, i. one or more modules of computer program instructions encoded on a computer storage medium for execution by or control of data processing equipment. Alternatively, or in addition, program instructions may be encoded on an artificially generated propagating signal, such as a machine-generated electrical, optical, or electromagnetic signal, generated to encode information for transmission to suitable receiving equipment for processing by data processing equipment. A computer storage medium, such as a computer-readable medium, may be or may be included in a computer-readable storage device, a computer-readable information storage card, a memory array, or a random access or sequential access storage device, or a combination of one or more of the foregoing. . Moreover, although the computer storage medium is not a propagating signal, such a computer storage medium may be a source or destination of computer program instructions encoded on an artificially generated propagating signal. Such computer storage media may also be or be included in one or more physical and/or non-volatile components or media (eg, multiple CDs, other types of discs, or other storage devices).

In some implementations, the operations discussed herein may be implemented as external hosting services provided by a server on a cloud computer network. For example, computer-readable storage media can be logically grouped and accessed within a cloud computing network. Servers in such a cloud computing environment may contain a cloud computing platform for providing cloud-based services. The terms "cloud", "cloud computing" and "cloud-based" may be used interchangeably as appropriate without deviating from the scope of the present invention. Cloud-based services may be hosted services executed by servers and provided over a communications network to a client platform to augment, supplement, or replace applications running locally on the client's computer. The schema may use cloud-based services to quickly receive updates to software, applications, and other resources that would otherwise take a long time to obtain before those resources could be delivered to the schema.

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 a standalone program. or a module, component, subroutine, object, or other unit suitable for use in a computer environment. A computer program may, but need not, correspond to a file in a file system. A program can 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 containing only the program in question, or in several coordinated files (for example, in files that store one or more modules, subroutines, or parts of code). The computer program may be deployed to run on a single computer or on multiple computers located in the same location or distributed over multiple locations and connected by a communications network.

The procedures and logic described herein may be implemented by one or more programmable processors executing one or more computer programs to act by operating on inputs and generating outputs and actions. These procedures and logic may also be implemented and the hardware may be implemented as a special purpose logic circuit such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

Processors suitable for executing a computer program may be microprocessors, either general purpose or special purpose, or any one or more processors of some type of digital computer. Typically, the processor must receive instructions and data from read only memory and/or random access memory. The main elements of a computer are a processor for carrying out actions in accordance with commands and one or more storage devices for storing commands and data. Typically, the computer may include or be operatively linked to receive data from and/or transmit data with one or more mass storage devices for storing data, such as magnetic, magneto-optical disks or optical disks. However, a computer does not need to have such devices. Moreover, the computer may be embedded in another device, such as a mobile phone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device (such as a USB flash drive), to name but a few. Devices suitable for storing computer program instructions include all types of non-volatile memory, media and storage devices, including semiconductor memory devices, such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM ) and flash memory devices; magnetic disks, such as internal hard drives or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks). The processor and storage device may be supplemented with or included in special purpose logic.

Although the present description contains many specific details, they should not be construed as limitations on the scope of any implementation or what may be claimed in the Claims, but only as a description of features specific to particular implementations. Some of the features discussed in the present description in the context of separate implementations may also be implemented together in one implementation. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations individually or in some suitable subcombination. Moreover, although the features may be described above as operating in certain combinations and even initially claimed as such, one or more features from the claimed combination may in some cases be excluded from it, and the claimed combination may be turned into a subcombination or into some subcombination variations.

Likewise, while the operations are shown in the drawings in a specific order, this should not be understood as a requirement that such operations be carried out in the order shown or in sequential order, or that all the illustrated operations be performed in order to achieve the desired results. In some circumstances, multitasking and parallel processing may be preferred and advantageous. Moreover, the separation of the various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should also be understood that the described software components and systems may, in general, be integrated together, in a single software product or packaged as several software products.

Thus, specific embodiments of the subject matter have been described above. Other implementation options are within the scope of the attached claims. In some cases, the actions referred to in these claims may be performed in a different order and still achieve the desired results. In addition, the procedures shown in the accompanying drawings do not necessarily require the particular execution order shown or the execution in sequential order. In some embodiments, multitasking and parallel processing may be preferred and advantageous.

While a number of variations are given herein, it should be understood that the described systems and methods may be embodied in a variety of other specific forms without departing from the spirit or scope of the present invention. The examples provided are to be considered illustrative and non-exhaustive, and the intentions are not limited to the details given here. For example, various elements or components may be combined or integrated into another system, or some features may be omitted or not implemented.

In addition, technologies, systems, subsystems, and methods, described and illustrated in various ways as discrete or separate, can be combined or integrated with other systems, modules, technologies, or methods without deviating from the scope of the present invention. Other objects shown or discussed as connected, directly connected, or communicating directly with each other may be connected or communicate indirectly through some interface, device, or intermediate component, whether electrically, mechanically, or otherwise. A person skilled in the art can find other examples, substitutions, substitutions or changes, without deviating from the meaning and scope discussed here.

Although only a number of variations have been given in the present description, it should be understood that the described systems and methods can be implemented in many other specific forms without deviating from the spirit and scope of the present invention. The examples presented here are to be considered illustrative and non-exhaustive only, and the intentions are not limited to the details given here. For example, various options or components may be combined or integrated in another system, or certain features may be omitted or not implemented.

In addition, technologies, systems, subsystems, and methods, described and illustrated in various ways as discrete or separate, can be combined or integrated with other systems, modules, technologies, or methods without deviating from the scope of the present invention. Other objects shown or discussed as connected, directly connected, or communicating directly with each other may be connected or communicate indirectly through some interface, device, or intermediate component, whether electrically, mechanically, or otherwise. A person skilled in the art can find other examples of substitutions, substitutions or changes without deviating from the meaning and scope discussed here.

Claims (67)

1. A method for constructing a list of the most probable modes, MPM, for intra prediction, the method comprises: determining whether a block to the left of the current coding block is available or not; determining whether a block is available above the current encoding block or not; using a planar mode, a DC mode, a vertical mode (VER_IDX index), a horizontal mode (HOR_IDX index), an intra prediction mode corresponding to the specified vertical mode with an offset of -4, an intra prediction mode corresponding to the specified vertical mode with an offset of 4, in order to obtain index values for the intra prediction mode for the current coding block, if one of the following conditions is met: the block to the left of the current coding block is not available, and the block above the current coding block is not available; the block to the left of the current coding block is unavailable, the block above the current coding block is available, and the intra prediction mode relative to the block above is a planar mode; the block to the left of the current coding block is unavailable, the block above the current coding block is available, and the intra prediction mode relative to the block above is the DC mode; the block to the left of the current coding block is available, the block above the current coding block is unavailable, and the intra prediction mode relative to the block to the left is planar mode; the block to the left of the current coding block is available, the block upstream of the current coding block is unavailable, and the intra prediction mode relative to the block to the left is the DC mode; the block to the left of the current coding block is available, the block upstream of the current coding block is available, the block-left intra-prediction mode is not an angle mode, and the intra-block-above prediction mode is not an angle mode. 2. The method according to p. 1, characterized in that this method additionally contains: obtaining the flag value of the most likely modes, MPM, for the current coding block; the value of the intra prediction mode index for the current coding block is obtained based on the value of the MPM modes flag for the current coding block and the indices of the planar mode, DC mode, vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra prediction mode corresponding to the vertical offset mode -4, intra prediction mode corresponding to vertical mode with offset 4. 3. The method according to p. 1, characterized in that this method additionally contains: obtaining the flag value of the most likely modes, MPM, for the current coding block; obtaining an index value of the intra prediction mode for the current coding block; the value of the intra prediction mode index for the current coding block is obtained based on the value of the MPM modes flag for the current coding block and the indices of the planar mode, DC mode, vertical mode (VER_IDX), horizontal mode (HOR_IDX), intra prediction mode corresponding to the vertical offset mode -4, intra prediction mode corresponding to vertical mode with offset 4. 4. The method of claim 3, wherein when the value of the MPM modes flag for the current coding block is 1, and the value of the intra prediction mode index for that current coding block is 0, then the intra prediction mode for the current coding block is a planar mode . 5. The method of claim 3, wherein when the value of the MPM modes flag for the current coding block is 0, the intra prediction mode for the current coding block does not match any of the following intra prediction modes: planar mode, DC mode, vertical mode (VER_IDX index), horizontal mode (HOR_IDX index), intra prediction mode corresponding to the vertical mode with an offset of -4, or intra prediction mode corresponding to the vertical mode with an offset of 4. 6. Method for decoding the current video block, where this decoding method contains: determining whether a block to the left of the current coding block is available or not; determining whether a block is available above the current encoding block or not; obtaining the flag value of the most likely modes, MPM, for the current block from the data bit stream; obtaining an MPM mode index for the current block from the data bitstream if the value of the MPM modes flag indicates that the intra prediction mode for the current block is an intra prediction mode included in the plurality of intra prediction MPM modes; obtaining an intra prediction mode index value for the current block based on the MPM mode index and the plurality of MPM modes for the current block; in which, if the intra prediction mode relative to the neighboring block to the left of the current block is a planar mode and the intra prediction mode relative to the neighboring block upstream of the current block is a planar mode, the plurality of MPM prediction modes includes: a planar mode, a DC mode, a vertical mode, a horizontal mode, an intra prediction mode corresponding to the -4 offset vertical mode, and an intra prediction mode corresponding to the 4 offset vertical mode. 7. The method of claim 6, wherein when the value of the MPM modes flag for the current coding block is 1, and the value of the intra prediction mode index for that current coding block is 0, then the intra prediction mode for the current coding block is a planar mode . 8. Method for decoding the current block of video, where this method of decoding contains: determining whether a block to the left of the current coding block is available or not; determining whether a block is available above the current encoding block or not; obtaining the flag value of the most likely modes, MPM, for the current block from the data bit stream; obtaining an MPM mode index for the current block from the data bitstream if the value of the MPM modes flag indicates that the intra prediction mode for the current block is an intra prediction mode included in the plurality of intra prediction MPM modes; obtaining an intra prediction mode index value for the current block based on the MPM mode index and the plurality of MPM modes for the current block; in which, if the intra prediction mode relative to the neighboring block to the left of the current block is planar mode and the intra prediction mode relative to the neighboring block upstream of the current block is DC mode, the set of MPM prediction modes includes: planar mode, DC mode, vertical mode, horizontal mode, an intra prediction mode corresponding to the first offset vertical mode, and an intra prediction mode corresponding to the second offset vertical mode. 9. The method of claim 8, wherein when the value of the MPM modes flag for the current coding block is 1, and the value of the intra prediction mode index for that current coding block is 0, then the intra prediction mode for the current coding block is a planar mode . 10. Method for decoding the current block of video, where this method of decoding contains: determining whether a block to the left of the current coding block is available or not; determining whether a block is available above the current encoding block or not; obtaining the flag value of the most likely modes, MPM, for the current block from the data bit stream; obtaining an MPM mode index for the current block from the data bitstream if the value of the MPM modes flag indicates that the intra prediction mode for the current block is an intra prediction mode included in the plurality of intra prediction MPM modes; obtaining an intra prediction mode index value for the current block based on the MPM mode index and the plurality of MPM modes for the current block; in which, if the neighboring block to the left of the current block is not available and the intra prediction mode relative to the neighboring block upstream of the current block is a planar mode, the plurality of MPM prediction modes includes: a planar mode, a DC mode, a vertical mode, a horizontal mode, an intra prediction mode corresponding to the -4 offset vertical mode, and an intra prediction mode corresponding to the 4 offset vertical mode. 11. The method of claim 10, wherein when the MPM mode flag value for the current coding block is 1, and the intra prediction mode index value for that current coding block is 0, then the intra prediction mode for the current coding block is a planar mode . 12. A method for decoding the current video block, where this decoding method comprises: determining whether a block to the left of the current coding block is available or not; determining whether a block is available above the current encoding block or not; obtaining the flag value of the most likely modes, MPM, for the current block from the data bit stream; obtaining an MPM mode index for the current block from the data bitstream if the value of the MPM modes flag indicates that the intra prediction mode for the current block is an intra prediction mode included in the plurality of intra prediction MPM modes; obtaining an intra prediction mode index value for the current block based on the MPM mode index and the plurality of MPM modes for the current block; in which, if the neighboring block to the left of the current block is unavailable and the neighboring block upstream of the current block is unavailable, the set of MPM prediction modes includes: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode corresponding to the vertical mode with a shift of -4 , and an intra prediction mode corresponding to the vertical mode with a shift of 4. 13. The method of claim 12, wherein when the value of the MPM modes flag for the current coding block is 1, and the value of the intra prediction mode index for that current coding block is 0, then the intra prediction mode for the current coding block is a planar mode . 14. A method for decoding the current video block, where this decoding method comprises: determining whether a block to the left of the current coding block is available or not; determining whether a block is available above the current encoding block or not; obtaining the flag value of the most likely modes, MPM, for the current block from the data bit stream; obtaining an MPM mode index for the current block from the data bitstream if the value of the MPM modes flag indicates that the intra prediction mode for the current block is an intra prediction mode included in the plurality of intra prediction MPM modes; obtaining an intra prediction mode index value for the current block based on the MPM mode index and the plurality of MPM modes for the current block; in which, if the intra prediction mode relative to the adjacent block to the left of the current block is planar mode and the adjacent block upstream of the current block is not available, the set of MPM prediction modes includes: planar mode, DC mode, vertical mode, horizontal mode, intra prediction mode corresponding to vertical mode with an offset of -4, and an intra prediction mode corresponding to the vertical mode with an offset of 4. 15. The method of claim 14, wherein when the value of the MPM modes flag for the current coding block is 1, and the value of the intra prediction mode index for that current coding block is 0, then the intra prediction mode for the current coding block is a planar mode . 16. Decoding device containing a processor circuit for implementing the method according to any one of paragraphs. 1-15. 17. Decoding device for building a list of the most probable modes, MPM, contains: one or more processors; and a non-volatile computer-readable storage medium coupled to the processors and storing programs for execution by those processors, wherein the programs, when executed by the processors, configure a decoder to implement a method according to any one of claims. 1-15.

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