RU2821337C2 - Encoder, decoder and corresponding methods harmonizing matrix-based intra prediction and secondary transformation kernel selection - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to video encoding means. Internal prediction mode of the current block is determined. Secondary transformation of the current block is selected based on the intra prediction mode determined for the current block. When the internal prediction mode is less than 0, the set of cores of inseparable secondary transformation is set equal to 1. When the internal prediction mode is equal to 0 or 1, the set of cores of inseparable secondary transformation is set equal to 0. When the internal prediction mode is greater than or equal to 2 and less than or equal to 12, the set of cores of the inseparable secondary transformation is set equal to 1. When the internal prediction mode is greater than or equal to 13 and less than or equal to 23, the set of cores of the inseparable secondary transformation is set equal to 2. When the internal prediction mode is greater than or equal to 24 and less than or equal to 44, the set of cores of the inseparable secondary transformation is set equal to 3. When the internal prediction mode is greater than or equal to 45 and less than or equal to 55, the set of cores of the inseparable secondary transformation is set equal to 2.

EFFECT: high efficiency of video encoding.

31 cl, 20 dwg, 8 tbl

Description

Cross reference to related applications

This patent application claims priority to U.S. Provisional Patent Application No. US 62/835487, filed April 17, 2019. The disclosure of the above patent application is incorporated herein by reference in its entirety.

Field of technology to which the invention relates

Embodiments of the present application (disclosure) generally relate to the field of image processing and, in particular, to intra prediction.

State of the art

Video encoding (video encoding and decoding) is used in a wide range of digital video applications, such as digital broadcast television, video transmission over the Internet and mobile networks, real-time conversational applications such as video chat, video conferencing, DVD and Blu-ray discs, systems for collecting and editing video content, as well as video cameras for security applications.

The amount of video data required to present even a relatively short video can be significant, which can lead to difficulties when the data must be streamed or otherwise transmitted over a communications network with limited bandwidth. Thus, video data is typically compressed before being transmitted over modern telecommunications networks. Video size can also be an issue when the video is stored on a storage device, as memory resources may be limited. Video compression devices often use software and/or hardware at the source to encode video data before transmission or storage, thereby reducing the amount of data required to represent digital video images. The compressed data is then received by the recipient's video decompressor, which decodes the video data. With limited network resources and ever-increasing demands for higher video quality, improved compression and decompression techniques are desired that improve compression rates with little or no loss in image quality.

The essence of the invention

The present disclosure attempts to mitigate or solve the above problem.

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

The present disclosure discloses an encoding method implemented by a decoding device or an encoding device, comprising: determining an intra prediction mode of a current block; and determining a selection of a secondary transform of the current block based on the intra prediction mode determined for the current block.

That is, the method according to the present disclosure determines the intra prediction mode of the current block and determines whether and how to perform secondary transformation of the current block based on the determined intra prediction mode.

In the method as described above, determining the selection of a secondary transform kernel for secondary transforming the current block may be based on the intra prediction mode index of the current block.

In the method described above, in case the current block is not predicted using the MIP mode, matrix-based intra prediction, a secondary transform kernel may be selected to secondary transform the current block.

Thus, in case an intra prediction block is predicted using MIP mode, for example, the value of the MIP flag can be used to indicate whether the block is predicted using MIP mode or not, secondary mapping is disabled for that intra prediction block, in other words , the secondary transform index value is set to 0, or the secondary transform index does not need to be decoded from the bitstream. Thus, harmonization of the MIP tool and the RST tool in terms of the choice of the secondary transformation kernel is achieved.

The above-described method may further comprise: disabling secondary transformation of the current block when the current block is predicted using the MIP mode.

In the method as described above, disabling the secondary conversion of the current block may comprise: setting the value of the secondary conversion indication information for the current block to a default value.

In the method as described above, it may be indicated whether the current block is predicted using the MIP mode according to the value of the MIP indication information.

In the method described above, in case the current block is not predicted using the MIP mode, a secondary transform can be selected according to the following table.

wherein:

sps_lfnst_enabled_flag equal to 1 indicates that lfnst_idx can be present in the inner encoding unit syntax; where sps_lfnst_enabled_fag equal to 0 indicates that lfnst_idx is not present in the internal encoding unit syntax;

intra_mip_flag [ x0 ][ y0 ] equal to 1 indicates that the intra prediction type for luma samples is matrix-based intra prediction. intra_mip_flag[ x0 ][ y0 ] equal to 0 indicates that the intra prediction type for luma samples is not matrix-based intra prediction; however, when intra_mip_flag[ x0 ][ y0 ] is missing, it is assumed to be 0;

lfnst_idx indicates whether and which of the two low-frequency non-separable transform kernels is used in the selected transform set. lfnst_idx equal to 0 indicates that the low frequency inseparable transform is not used in the current encoding unit; however, when lfnst_idx is missing, it is assumed to be 0;

transform_skip_flag [ x0 ][ y0 ][ cIdx ] indicates whether the transform is applied to the corresponding transform block or not.

The above-described method may further comprise: obtaining an intra prediction mode index of the current block according to the matrix-based intra prediction, MIP, mode index of the current block, and the size of the current block; selecting a secondary transform kernel to secondary transform the current block based on the intra prediction mode index of the current block.

Thus, during the secondary transform kernel selection process, when a block is predicted using the MIP mode, one of the set of secondary transform kernels is considered to be used for that block.

In the method described above, the intra prediction mode index of the current block can be obtained according to the mapping ratio among the MIP mode index, the size of the current block, the mapping ratio can be specified according to a predetermined table.

The above-described method may further comprise using a secondary transform kernel to secondary transform the current block when the current block is predicted using a matrix-based intra prediction mode, MIP.

In the method described above, the secondary transform core may be one of the secondary transform cores that are used for non-MIP modes.

In the method described above, the secondary transform kernel may be different from any of the secondary transform kernels that are used for non-MIP modes.

In the method as described above, in which in case the current block is predicted using a MIP mode, a lookup table may be used to map the MIP mode index to a regular internal mode index, and a set of secondary conversion kernels may be selected based on this regular internal mode index. mode.

In the method described above, the MIP mode index can be mapped to the normal internal mode index based on the following table:

IntraPredModeY[ xNbX ][ yNbX ] block size type, sizeId 0 1 2 0 0 0 1 1 18 1 1 2 18 0 1 3 0 1 1 4 18 0 18 5 0 22 0 6 12 18 1 7 0 18 0 8 18 1 1 9 2 0 50 10 18 1 0 eleven 12 0 12 18 1 13 18 0 14 1 44 15 18 0 16 18 50 17 0 1 18 0 0 19 50 20 0 21 50 22 0 23 56 24 0 25 50 26 66 27 50 28 56 29 50 thirty 50 31 1 32 50 33 50 34 50

in this case, the selection of a set of secondary transformations can be performed in accordance with the following table:

IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1

The above-described method may further comprise: providing four sets of transformation kernels having an index of 0, 1, 2, 3 of the transformation kernel set, respectively, wherein each set of transformation kernels of the four sets of transformation kernels may contain two transformations; selecting a reduced secondary transform matrix, RST, by determining a set of transform kernels from four sets of transform kernels to be applied to the current block according to the current block's intra prediction mode, as follows: if the current internal block is predicted using the cross-component linear mode model, CCLM, or using MIP mode, selecting the set of transformation kernels having transformation kernel set index 0; otherwise, select a set of transformation kernels using the current block's intra prediction mode index value and the following table:

IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1

The described method may further comprise: providing four sets of transformation kernels having index 0, 1, 2, 3 of the transformation kernel set, respectively, wherein each set of transformation kernels of the four sets of transformation kernels may contain two transformations; providing a fifth set of transformation kernels having a set of transformation kernels index 4, wherein the fifth set of transformation kernels has the same dimensions as the sets of transformation kernels having a set of transformation kernels index 0-3; wherein the fifth set of transformation kernels is retrained based on the same machine learning method and the input training set for the MIP mode. selecting a reduced secondary transform matrix, RST, by determining a set of transform kernels from five sets of transform kernels to be applied to the current block according to the current block's intra prediction mode, as follows: if the current internal block is predicted using the cross-component linear mode models, CCLM, selecting a set of transformation kernels having index 0 of the set of transformation kernels; if the current internal block is predicted using the MIP mode, selecting a set of transformation kernels having a set of transformation kernels index 4; otherwise, select a set of transformation kernels using the current block's intra prediction mode index value and the following table:

IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1

Thus, during the secondary transform kernel selection process, when a block is predicted using the MIP mode, a trained set of secondary transform kernels is considered to be used for that block. The trained set of secondary transformation kernels may be different from the set of transformation kernels in the examples above.

The present disclosure further provides an encoder including processing circuitry for performing the method described above when implemented by an encoding apparatus.

The present disclosure further provides a decoder including processing circuitry for performing the method as described above when implemented by a decoding apparatus.

The present disclosure further provides a computer program product containing program code for performing the method as described above.

The present disclosure further provides a decoder comprising: one or more processors; and a non-transitory computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the program, when executed by the processors, configures a decoder to perform the method as described above when implemented by a decoding apparatus.

The present disclosure further provides an encoder comprising: one or more processors; and a non-transitory computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the program, when executed by the processors, configures the encoder to perform the method as described above when implemented by the encoder.

The present disclosure further provides a decoder comprising: a determination block configured to determine an intra prediction mode of the current block; and a selector configured to determine a secondary transform selection of the current block based on an intra prediction mode determined for the current block.

The present disclosure further provides an encoder comprising: a determination block configured to determine an intra prediction mode of the current block; and a selector configured to determine a secondary transform selection of the current block based on an intra prediction mode determined for the current block.

The above and other goals are achieved by the invention according to independent claims. Additional forms of implementation are obvious from the dependent claims, description and figures.

The method according to the first aspect of the invention can be carried out by a device according to the third aspect of the invention. Additional features and forms of implementation of the method according to the third aspect of the invention correspond to the features and forms of implementation of the device according to the first aspect of the invention.

The method according to the second aspect of the invention can be carried out by the device according to the fourth aspect of the invention. Additional features and forms of implementation of the method according to the fourth aspect of the invention correspond to the features and forms of implementation of the device according to the second aspect of the invention.

According to a fifth aspect, the invention relates to an apparatus for decoding a video stream, including a processor and a memory. The memory stores instructions that cause the processor to execute the method according to the first aspect.

According to a sixth aspect, the invention relates to an apparatus for encoding a video stream including a processor and a memory. The memory stores instructions that cause the processor to execute the method according to the second aspect.

According to a seventh aspect, there is provided a computer-readable medium on which instructions are stored that, when executed, cause operation of one or more processors configured to encode video data. The instructions cause one or more processors to perform a method according to the first or second aspect or any possible embodiment of the first or second aspect.

According to an eighth aspect, the invention relates to a computer program containing program code for performing a method according to the first or second aspect or any possible embodiment of the first or second aspect when executed on a computer.

Details of one or more embodiments are set forth in the accompanying drawings and in the following description. Other features, objects and advantages will be apparent from the description, drawings and claims.

Brief description of drawings

In the following embodiments, the inventions are described in more detail with reference to the accompanying figures and drawings, in which:

Fig. 1A is a block diagram showing an example of a video encoding system configured to implement embodiments of the invention;

Fig. 1B is a block diagram showing another example of a video encoding system configured to implement embodiments of the invention;

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

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

Fig. 4 is a block diagram illustrating an example of an encoding device or a decoding device;

Fig. 5 is a block diagram illustrating another example of an encoding device or a decoding device;

Fig. 6 is a block diagram illustrating an example of MIP mode matrix multiplication for a 4×4 block

Fig. 7 is a block diagram illustrating an example of MIP mode matrix multiplication for an 8×8 block

Fig. 8 is a block diagram illustrating an example of MIP mode matrix multiplication for an 8×4 block

Fig. 9 is a block diagram illustrating an example of MIP mode matrix multiplication for a 16×16 block

Fig. 10 is a flowchart illustrating an exemplary secondary conversion process

Fig. 11 is a flowchart illustrating an exemplary process of multiplying the secondary transform kernel of an encoding and decoding device

Fig. 12 is a block diagram illustrating an example reduction in the size of the secondary transform kernel from 16x64 to 16x48.

Fig. 13 is a block diagram illustrating an example of MPM MIP recovery based on the location of neighboring blocks.

Fig. 14 is a block diagram illustrating another example of MPM MIP recovery based on the location of neighboring blocks.

Fig. 15 illustrates a method implemented by a decoding device or an encoding device, the method according to the present disclosure.

Fig. 16 illustrates an encoder according to the present disclosure.

Fig. 17 illustrates a decoder according to the present disclosure.

Fig. 18 is a block diagram showing an exemplary structure of a content delivery system 3100 that implements a content delivery service.

Fig. 19 is a block diagram showing the structure of an exemplary terminal device.

The following identical reference numerals refer to identical or at least functionally equivalent functions unless explicitly stated otherwise.

Carrying out the invention

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

For example, it will be understood that the disclosure associated with the described method may also apply to a corresponding device or system configured to perform the method, and vice versa. For example, if one or a plurality of specific method steps are described, the corresponding apparatus may include one or a plurality of blocks, such as functional blocks, to perform the one or multiple method steps described (e.g., one block performing one or a plurality of steps, or a plurality of blocks, each of which performs one or more of a plurality of steps), even if such one or more blocks are not explicitly described or illustrated in the figures. On the other hand, for example, if a particular device is described in terms of one or a plurality of blocks, such as functional blocks, the corresponding method may include one step for performing the functionality of the one or multiple blocks (e.g., one step performing the functionality of the one or multiple blocks , or a plurality of steps, each of which performs the functionality of one or more of a plurality of blocks), even if such one or multiple steps are not explicitly described or illustrated in the figures. figures. It is further understood that features of various exemplary embodiments and/or aspects described herein may be combined with each other unless specifically stated otherwise.

Video encoding generally refers to the processing of a sequence of images that form a video or video sequences. Instead of the term "image", the terms "frame" or "picture" may be used interchangeably in the field of video coding. Video encoding (or encoding in general) contains two parts: video encoding and video decoding. Video encoding is performed at the source side and typically involves processing (eg, through compression) of the source video images to reduce the amount of data required to represent the video images (for more efficient storage and/or transmission). Video decoding is performed at the receiver (destination) side and usually contains reverse processing compared to the encoder for reconstructing video images. Embodiments relating to "coding" video images (or images in general) are to be understood as referring to "encoding" or "decoding" video images or corresponding video sequences. The combination of the encoding part and the decoding part is also called a codec (CODEC, Coding and Decoding).

In the case of lossless video encoding, the original video images can be restored, i.e. the restored video images are of the same quality as the original video images (assuming there is no transmission loss or other data loss during storage or transmission). In the case of lossy video encoding, additional compression is performed, for example through quantization, to reduce the amount of data representing video images that cannot be fully reconstructed at the decoder, i.e. The quality of the restored video images is lower or worse compared to the quality of the original video images.

Several video coding standards belong to the group of “hybrid lossy video codecs” (that is, they combine spatial and temporal prediction in the sample domain and 2D transform coding to apply quantization in the transform domain). Each image of a video sequence is usually divided into a set of non-overlapping blocks, and coding is usually performed at the block level. In other words, in an encoder, video is typically processed, i.e. encoded, at the block (video block) level, for example using spatial (intra picture) prediction and/or temporal (inter picture) prediction to form a prediction block, block prediction is subtracted from the current block (the block that is currently being processed/to be processed) to obtain a residual block, the residual block is transformed and this residual block is quantized in the transform domain to reduce the amount of data (compression) to be transmitted, whereas in the decoder the inverse encoder-versus processing is applied to an encoded or compressed block to recover the current block for presentation. In addition, the encoder duplicates the decoder's processing loop so that they will both generate identical predictions (eg, internal and external predictions) and/or reconstructions for processing, ie, encoding, of subsequent blocks.

In the following embodiments, the video encoding system 10, video encoder 20 and video decoder 30 are described based on FIGS. 1-3.

Fig. 1A is a schematic block diagram illustrating an example encoding system 10, such as video encoding system 10 (or encoding system 10 for short), which may use the methods of the present application. Video encoder 20 (or encoder 20 for short) and video decoder 30 (or decoder 30 for short) of video encoding system 10 are examples of devices that may be configured to perform methods in accordance with various examples described herein.

As shown in FIG. 1A, the encoding system 10 includes a source device 12 configured to provide encoded image data 21, for example, to a destination device 14 for decoding the encoded image data 13.

The source device 12 contains an encoder 20 and can additionally, i.e. optionally comprise an image source 16, a preprocessor (or pre-processing unit) 18, such as an image preprocessor 18, and a communications interface or communications unit 22.

The image source 16 may contain or be any type of image capturing device, such as a camera for capturing a real world image, and/or any type of imaging device, such as a computer graphics processor for generating a computer animated image, or any type of other device for capturing and/or providing a real-world image, a computer-generated image (e.g., screen content, virtual reality (VR) image), and/or any combination thereof (e.g., augmented reality (AR) image). The snapshot source can be any type of memory or storage that stores any of the above snapshots.

In contrast to the preprocessor 18 and the processing performed by the preprocessing unit 18, the image or image data 17 may also be referred to as a raw image or raw image data 17.

The preprocessor 18 is configured to receive (raw) image data 17 and perform preprocessing on the image data 17 to obtain a preprocessed image 19 or preprocessed image data 19 . Preprocessing performed by preprocessor 18 may, for example, comprise cropping, color format conversion (eg, RGB to YCbCr), color correction, or noise reduction. It can be understood that the preprocessing unit 18 may be an optional component.

Video encoder 20 is configured to receive preprocessed image data 19 and provide encoded image data 21 (further details will be described below, for example based on FIG. 2). The communication interface 22 of the source device 12 may be configured to receive encoded image data 21 and transmit this encoded image data 21 (or any further processed version thereof) over the communication channel 13 to another device, such as the destination device 14 or any other device, for saving or immediate restoration.

The recipient device 14 includes a decoder 30 (eg, video decoder 30) and may additionally, i.e. optionally comprising a communication interface or communication unit 28, a post processor 32 (or post processing unit 32) and a display device 34.

The communication interface 28 of the destination device 14 is configured to receive the encoded image data 21 (or any further processed version thereof), for example directly from the source device 12 or from any other source, such as a storage device, such as a storage device for the encoded image data, and provide encoded image data 21 into decoder 30.

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

The communications interface 22 may, for example, be configured to package the encoded image data 21 into an appropriate format, such as packets, and/or process the encoded image data using any type of transmission encoding or processing for transmission over a communications link or network.

The communication interface 28, which is analogous to the communication interface 22, may, for example, be configured to receive transmitted data and process the transmission data using any kind of appropriate decoding or transmission processing and/or decompression to obtain encoded image data 21.

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

The decoder 30 is configured to receive encoded image data 21 and provide decoded image data 31 or decoded image 31 (further details will be described below, for example, based on FIG. 3 or FIG. 5.

The post-processor 32 of the recipient device 14 is configured to post-process the decoded image data 31 (also called reconstructed image data), such as the decoded image 31, to obtain post-processed image data 33, such as the post-processed image 33. Post-processing performed by block 32 post-processing may include, for example, color format conversion (eg, from YCbCr to RGB), color correction, cropping or resampling, or any other processing, for example, to prepare the decoded image data 31 for display, for example, using display device 34.

The display device 34 of the recipient device 14 is configured to receive post-processed image data 33 for displaying the image, for example, to a user or viewer. The display device 34 may be or include any type of display for presenting the reconstructed image, such as an integrated or external display or monitor. The displays may, for example, comprise liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs), plasma displays, projectors, micro-LED displays, liquid crystal on silicon (LCoS), digital light processor (DLP), or any other type of display .

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

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

Encoder 20 (eg, video encoder 20) or decoder 30 (eg, video decoder 30) or both encoder 20 and decoder 30 may be implemented through a processing circuit as shown in FIG. 1B, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, hardware, dedicated video encoding, or any combination thereof. Encoder 20 may be implemented through processing circuit 46 to implement various modules, as discussed with respect to encoder 20 in FIG. 2 and/or any other encoding system or subsystem described herein. The decoder 30 may be implemented through a processing circuit 46 to implement various modules, as discussed with respect to the decoder 30 of FIG. 3 and/or any other decoder system or subsystem described herein. The processing circuit may be configured to perform various operations, which will be described below. As shown in FIG. 5, if the methods are partially implemented in software, the apparatus may store instructions for the software on a suitable non-transitory computer-readable storage medium and may execute the instructions in hardware using one or more processors to perform the methods of this disclosure. Either of video encoder 20 and video decoder 30 may be integrated as part of a combined encoder/decoder (CODEC) in a single device, for example, as shown in FIG. 1B.

Source device 12 and destination device 14 may include any of a wide range of devices, including any type of portable or desktop devices, such as laptops or notebook computers, mobile phones, smartphones, tablets or tablet computers, cameras, desktop computers, set-top boxes , televisions, display devices, digital media players, game consoles, video streaming devices (such as content service servers or content delivery servers), broadcast receiving device, broadcast transmitting device, or the like, and may use or dispense with any type of operating system. In some cases, source device 12 and destination device 14 may be equipped for wireless communication. Thus, source device 12 and destination device 14 may be wireless communication devices.

In some cases, the video encoding system 10 illustrated in FIG. 1A is an example only, and the methods of the present application may be applied to video encoding settings (such as video encoding or video decoding) that do not necessarily involve transmitting any data between encoding and decoding devices. In other examples, data is retrieved from local memory, streamed over a network, or the like. A video encoding device may encode and store data into memory, and/or a video decoding device may retrieve and decode data from memory. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but simply encode data into memory and/or retrieve and decode data from memory.

For convenience of description, embodiments of the present invention are described herein, for example, with reference to High-Efficiency Video Coding (HEVC) or Versatile Video coding (VVC) reference software, a next-generation video coding standard being developed by the joint collaboration group. on video coding (Joint Collaboration Team on Video Coding, JCT-VC) of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Motion Picture Experts Group (MPEG). One skilled in the art will understand that embodiments of the present invention are not limited to HEVC or VVC.

Encoder and encoding method

Fig. 2 shows a schematic block diagram of an exemplary video encoder 20 that is configured to implement the methods of the present application. In the example in FIG. 2, video encoder 20 includes an input 201 (or input interface 201), a remainder calculation block 204, a transform processing block 206, a quantization block 208, an inverse quantization block 210 and an inverse transform processing block 212, a restoration block 214, a loop filter block 220, a buffer 230 ( Decoded Picture Buffer (DPB) of decoded pictures, a mode selector 260, an entropy encoder 270, and an output 272 (or output interface 272). The mode selection block 260 may include an inter prediction block 244, an intra prediction block 254, and a partitioning block 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The video encoder 20 shown in FIG. 2 may also be called a hybrid video encoder or a video encoder according to a hybrid video codec.

The remainder calculation block 204, transform processing block 206, quantization block 208, mode selection block 260 may relate to the formation of the forward signal path of the encoder 20, while the inverse quantization block 210, inverse transform processing block 212, restoration block 214, buffer 216, contour filter 220, decoded image buffer (DPB) 230, inter prediction block 244, and intra prediction block 254 may relate to generating a reverse signal path of video encoder 20, wherein the reverse signal path of video encoder 20 corresponds to the signal path of the decoder (see video decoder 30 on Fig. 3). The inverse quantization unit 210, the inverse transform processing unit 212, the restoration unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter prediction unit 244, and the intra prediction unit 254 are also relevant to forming the “Built-in decoder” of the video encoder 20.

Images and image division (images and blocks)

The encoder 20 may be configured to receive, for example, through input 201, an image 17 (or image data 17), for example an image from a sequence of images forming a video or video sequence. The received image or image data may also be a preprocessed image 19 (or preprocessed image data 19). For simplicity, the following description refers to picture 17. Picture 17 may also be referred to as the current picture or the picture to be encoded (particularly in video encoding, to distinguish the current picture from other pictures, such as previously encoded and/or decoded pictures of the same video sequence, i.e. a video sequence that also contains the current image).

An image (digital) is, or can be viewed as, a two-dimensional array or matrix of samples with intensity values. A selection in an array may also be referred to as a pixel (short form of image element) or pel (image element). The number of samples in the horizontal and vertical direction (or axis) of the array or image determines the size and/or resolution of the image. Three color components are usually used to represent color, i.e. the image may be represented by or include three arrays of samples. In RBG format, or color space, an image contains a corresponding array of red, green, and blue color samples. However, in video encoding, each pixel is typically represented in a luminance-chrominance format or color space, such as YCbCr, which contains a luminance component, denoted Y (sometimes L is also used instead), and two chrominance components (chrominance components), denoted Cb and Cr. The Y component of luminance (or luma for short) represents the brightness or intensity of the gray level (such as in a grayscale image), while the two components Cb and Cr are chrominance (or chrominance for short). chroma) represent components of chromaticity or color information. Accordingly, an image in YCbCr format contains an array of luminance samples with luminance sample values (Y) and two chrominance sample arrays with chrominance values (Cb and Cr). Images in RGB format can be converted or converted to YCbCr format and vice versa, a process also known as color conversion or conversion. If the image is monochrome, it can only contain an array of luminance samples. Accordingly, the image may be, for example, an array of luminance samples in a monochrome format, or an array of luminance samples and two corresponding arrays of chrominance samples in 4:2:0, 4:2:2 and 4:4:4 color formats.

Embodiments of video encoder 20 may include an image splitter (not shown in FIG. 2) configured to divide image 17 into multiple (usually non-overlapping) image blocks 203. These blocks may also be called root blocks, macroblocks (H.264/AVC), or Coding Tree Blocks (CTB), or Coding Tree Units (CTUs) (H.265/HEVC and VVC). The image splitter may be configured to use the same block size for all images in a video sequence and a corresponding grid defining the block size, or to vary the block size between images or subsets or groups of images and divide each image into appropriate blocks.

In additional embodiments, the video encoder may be configured to receive directly a block 203 of an image 17, such as one, more, or all of the blocks forming the image 17. The image block 203 may also be referred to as a current image block or an image block to be encoded.

Like image 17, image block 203 is again, or can be viewed as, a two-dimensional array or matrix of samples with intensity values (sample values), albeit smaller in size than image 17. In other words, block 203 may contain, for example, one array of samples (e.g. , a luminance array in the case of a monochrome image 17 or a luminance or chrominance array in the case of a color image) or three sample arrays (for example, luminance and two chroma arrays in the case of a color image 17) or any other number and/or type of arrays depending on the color used format. The number of samples in the horizontal and vertical direction (or axis) of block 203 determines the size of block 203. Accordingly, the block may, for example, be an MxN array of discrete samples (M-column by N-row) or an MxN array of transform coefficients.

Embodiments of video encoder 20 shown in FIG. 2 may be configured to encode the image 17 block by block, such that encoding and prediction is performed for each block 203.

Embodiments of video encoder 20, as shown in FIG. 2 may be further configured to divide and/or encode an image using slices (also referred to as video slices), wherein the image may be divided into or encoded using one or more slices (usually non-overlapping), and each slice may contain one or more units (for example, CTU).

Embodiments of video encoder 20 shown in FIG. 2 may be further configured to divide and/or encode an image using tile groups (also called video tile groups) and/or tiles (also called video tiles), wherein the image may be divided into or encoded with using one or more groups of tiles (typically non-overlapping), and each group of tiles may contain, for example, one or more blocks (eg, CTUs) or one or more tiles, wherein each tile, for example, may have rectangular in shape and may contain one or more blocks (eg, CTUs), such as full or partial blocks.

Calculating the remainder

Residual calculation block 204 may be configured to calculate residual block 205 (also referred to as residual 205) based on image block 203 and prediction block 265 (more details about prediction block 265 are provided below), for example, by subtracting the sample values of prediction block 265 from the values samples the image block 203 sample by sample (pixel by pixel) to obtain a residual block 205 in the sample region.

Conversion

Transform processing unit 206 may be configured to apply a transform, such as a Discrete Cosine Transform (DCT) or a Discrete Sine Transform (DST), to the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain. . The transform coefficients 207 may also be referred to as residual transform coefficients and represent the residual block 205 in the transform domain.

Transform processing block 206 may be configured to apply DCT/DST integer approximations, such as the transforms defined for H.265/HEVC. Compared to the orthogonal DCT transform, such integer approximations are typically scaled by a certain factor. To preserve the norm of the residual block that is processed by the forward and inverse transforms, additional scaling factors are applied as part of the transform process. Scaling factors are typically chosen based on certain constraints, e.g., scaling factors are powers of two for shift operations, bit depth of transform factors, tradeoff between accuracy and implementation cost, etc. Specific scaling factors, for example, are specified for inverse transform, such as by block 212 inverse transform processing (and the corresponding inverse transform, such as the inverse transform processing unit 312 in the video decoder 30), and the corresponding scaling factors for the forward transform, such as the transform processing unit 206, can be set appropriately in the encoder 20.

Embodiments of video encoder 20 (respectively transform processing unit 206) may be configured to output transform parameters, such as the type of transform or transforms, for example, directly or encoded or compressed via entropy encoding unit 270, so that, for example, video decoder 30 can receive and use conversion parameters for decoding.

Quantization

The quantization unit 208 may be configured to quantize the transform coefficients 207 to obtain quantized coefficients 209, for example by applying scalar quantization or vector quantization. Quantized coefficients 209 may also be referred to as quantized transform coefficients 209 or quantized residual coefficients 209.

The quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, an n-bit transform factor may be rounded to an m-bit transform factor during quantization, where n is greater than m. The degree of quantization can be changed by adjusting the quantization parameter (QP). For example, for scalar quantization, different scaling may be applied to achieve finer or coarser quantization. Smaller quantization step sizes correspond to finer quantization, while larger quantization step sizes correspond to coarser quantization. The applicable quantization step size may be specified by the quantization parameter (QP). The quantization parameter may, for example, be an index to a predetermined set of applicable quantization step sizes. For example, small quantization parameters may correspond to fine quantization (small quantization step sizes), and large quantization parameters may correspond to coarse quantization (large quantization step sizes), or vice versa. Quantization may include dividing by a quantization step size, and corresponding and/or inverse dequantization, such as by inverse quantization unit 210, may include multiplying by a quantization step size. Embodiments in accordance with some standards, such as HEVC, may be configured to use a quantization parameter to determine the quantization step size. Typically, the quantization step size can be calculated based on the quantization parameter using a fixed point approximation of the equation involving division. Additional scaling factors can be introduced for quantization and dequantization to recover the residual block norm that may have been changed due to the scaling used in the fixed point approximation of the above equation for the quantization step size and the quantization parameter. In one exemplary implementation, inverse transform scaling and dequantization may be combined. Alternatively, customized quantization tables can be used and signaled from encoder to decoder, for example in a bitstream. Quantization is a lossy operation in which losses increase as the size of the quantization steps increases.

Embodiments of video encoder 20 (respectively quantization block 208) may be configured to output quantization parameters (QPs), for example, directly or encoded through entropy encoding block 270, so that, for example, video decoder 30 can receive and apply the quantization parameters for decoding.

Inverse quantization

The inverse quantization block 210 is configured to apply the inverse quantization of the quantization block 208 to the quantized coefficients to obtain the dequantized coefficients 211, for example, by applying an inverse quantization scheme to that applied by the quantization block 208, based on or using the same quantization step size as the block 208 quantization. The dequantized coefficients 211 may also be referred to as the dequantized residual coefficients 211 and correspond - although they are typically not identical to the transform coefficients due to quantization loss - to the transform coefficients 207.

Reverse conversion

The inverse transform processing unit 212 is configured to apply an inverse transform relative to the transform applied by the transform processing unit 206, such as an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST) or other inverse transforms to obtain the reconstructed residual block 213 (or corresponding dequantized coefficients 213) in the sample area. The reconstructed residual block 213 may also be referred to as a transform block 213.

Recovery

A reconstruction block 214 (e.g., an add block or an adder 214) is configured to add a transform block 213 (i.e., a reconstructed residual block 213) with a prediction block 265 to obtain a reconstructed block 215 in the sample domain, such as through sample-by-sample addition. - sample values of the reconstructed residual block 213 and sample values of the prediction block 265.

Filtration

Loop filter block 220 (or "loop filter" 220 for short) is configured to filter the reconstructed block 215 to obtain a filtered block 221, or more generally to filter the reconstructed samples to obtain filtered samples. The edge filter unit, for example, is configured to smooth pixel transitions or otherwise improve video quality. Loop filter block 220 may include one or more loop filters, such as a deblocking filter, a Sample-Adaptive Offset (SAO) filter, or one or more other filters, such as a two-way filter, an Adaptive Loop filter Filter, ALF), anti-aliasing, sharpening or joint filters, or any combination of them. Although the loop filter block 220 is shown in FIG. 2 as a loop filter, in other configurations the loop filter block 220 may be implemented as a post-loop filter. Filtered block 221 may also be referred to as filtered reconstructed block 221.

Embodiments of video encoder 20 (respectively, loop filter block 220) may be configured to output loop filter parameters (such as sample-adaptive offset information), such as directly or encoded through entropy encoding block 270, so that, for example, decoder 30 can receive and apply similar loop filter parameters or corresponding loop filters for decoding.

Decoded Image Buffer

Decoded picture buffer (DPB) 230 may be a memory that stores reference pictures or, more generally, reference picture data for encoding video data by video encoder 20. DPB 230 may be formed by any of a variety of storage devices, such as dynamic random access memory (DRAM). DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The decoded picture buffer (DPB) 230 may be configured to store one or more filtered blocks 221. The decoded picture buffer 230 may be further configured to store other previously filtered blocks, such as previously reconstructed and filtered blocks 221, of the same current image, or different images, such as previously recovered images, and can provide complete previously recovered ones, i.e. decoded, images (and corresponding reference blocks and samples) and/or partially reconstructed current image (and corresponding reference blocks and samples), for example, for inter-prediction. Decoded picture buffer (DPB) 230 may also be configured to store one or more unfiltered reconstructed blocks 215, or generally unfiltered reconstructed samples, such as if reconstructed block 215 is not filtered by loop filter block 220, or any other further processed version of the reconstructed blocks. or samples.

Mode selection (separation and prediction)

The mode selection unit 260 includes a partitioning unit 262, an inter-prediction unit 244, and an intra-prediction unit 254, and is configured to receive or obtain original image data, such as the original block 203 (current block 203 of the current image 17), and reconstructed image data, such as filtered and /or unfiltered reconstructed samples or blocks of the same (current) image and/or from one or a plurality of previously decoded images, such as from decoded image buffer 230 or other buffers (eg, a line buffer, not shown). The reconstructed image data is used as reference image data for prediction, such as inter prediction or intra prediction, to obtain a prediction block 265 or a predictor 265.

The mode selector 260 may be configured to determine or select a split for a prediction mode of the current block (including no split) and a prediction mode (eg, intra or inter prediction mode) and generate a corresponding prediction block 265 that is used to calculate the residual block 205 and to restore the recovered block 215.

Embodiments of the mode selector 260 may be configured to select a split and prediction mode (e.g., from those supported by or available to the mode selector 260) that provides the best match, or in other words, the minimum remainder (the minimum remainder means the best compression for transmission or storage), or minimal signaling overhead (minimum signaling overhead means better compression for transmission or storage), or which takes into account or balances both factors. The mode selector 260 may be configured to determine a division and prediction mode based on Rate Distortion Optimization (RDO), that is, selecting a prediction mode that provides minimal rate distortion. Terms such as "best", "minimum", "optimal", etc. in this context do not necessarily refer to the all-encompassing "best", "minimum", "optimal", etc., but may also refer to meeting a selection or termination criterion, such as when a value exceeds or falls below a threshold, or other constraints, potentially leading to "suboptimal selection" but reducing complexity and processing time.

In other words, partitioner 262 may be configured to partition block 203 into smaller block sections or sub-blocks (which form blocks again), for example, iteratively using quadtree (QT) partitioning, binary tree partitioning (BT), or ternary tree partitioning (TT). ) or any combination thereof, and performing, for example, prediction for each of the sections of the block or sub-blocks, wherein the mode selection comprises selecting a tree structure of the shared block 203, and the prediction modes are applied to each of the sections of the block or sub-blocks.

Next, the partitioning (e.g., through partitioner 260) and prediction processing (via inter prediction unit 244 and intra prediction unit 254) performed by the exemplary video encoder 20 are explained in more detail.

Splitting

A splitter 262 may divide (or split) the current block 203 into smaller sections, such as smaller square or rectangular sized blocks. These smaller blocks (which may also be called subblocks) can be further divided into even smaller sections. This is also called tree partitioning or hierarchical tree partitioning, in which the root block, for example at root level 0 of the tree (hierarchy level 0, depth 0), can be recursively partitioned, for example divided into two or more blocks of the next lower tree level, such as nodes at tree level 1 (hierarchy level 1, depth 1), whereby these blocks can be again divided into two or more blocks of the next lower level, such as tree level 2 (hierarchy level 2, depth 2), etc. until the split will not complete, for example because a termination criterion has been met, such as reaching the maximum tree depth or minimum block size. Blocks that are not further divided are also called leaf blocks or leaf nodes of a tree. A tree using two partitions is called a binary tree (BT), a tree using three partitions is called a ternary tree (TT), and a tree using four partitions is called a quadtree (QT).

As mentioned previously, the term "block" as used herein may be a portion, particularly a square or rectangular portion of an image. With respect to, for example, HEVC and VVC, a block may be or correspond to a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU) and a transform unit (TU) and/or corresponding blocks, such as a coding tree block (CTB ), a coding block (CB), a transform block (TB), or a prediction block (PB).

For example, a coding tree unit (CTU) may be or contain a CTB of luma samples, two corresponding CTBs of chroma samples of an image that has three arrays of samples, or a CTB of samples of a monochrome image or an image that is encoded using three separate color planes and the syntax structures used for encoding samples. Accordingly, a coding tree block (CTB) may be an N×N block of samples for some value of N, such that dividing a component by the CTB is a division. A coding unit (CU) may be or comprise a luma sample encoding unit, two corresponding chroma sample encoding units of an image that has three sample arrays, or a monochrome image sample encoding unit or an image that is encoded using three separate color planes and syntax structures used for encoding samples. Accordingly, a coding block (CB) may be an M×N block of samples for some values of M and N, so that dividing the CTB into coding blocks is a division.

In embodiments, for example, according to HEVC, a coding tree unit (CTU) can be partitioned into CUs using a quadtree structure designated as a coding tree. The decision of whether to encode an image region using inter-image (temporal) or intra-image (spatial) prediction is made at the CU level. Each CU can be further partitioned into one, two or four PUs according to the PU partition type. Within a single PU, the same prediction process is applied, and the relevant information is passed to the PU-based decoder. After obtaining the residual block by applying a prediction process based on the partition type on the PU, the CU can be divided into transform units (TUs) according to another quadtree structure similar to the encoding tree for the CU.

In embodiments, for example, in accordance with the newest video coding standard currently under development, called Versatile Video Coding (VVC), for example, a combined quadtree and binary tree (QTBT) partitioning is used to partition the encoding block. In a block structure, a QTBT CU can be either square or rectangular in shape. For example, a coding tree unit (CTU) is first divided into a quadtree structure. The leaf nodes of a quadtree are further separated by a binary tree or ternary (or triple) tree structure. The leaf nodes of a partitioning tree are called coding units (CUs), and this partitioning is used to process prediction and transformation without any further partitioning. This means that CU, PU and TU have the same block size in the QTBT coding block structure. In parallel, a multiple partition, such as a ternary tree partition, can be used in conjunction with the QTBT block structure.

In one example, the mode selector 260 of the video encoder 20 may be configured to perform any combination of partitioning methods described herein.

As described above, video encoder 20 is configured to determine or select the best or optimal prediction mode from a set of (eg, predetermined) prediction modes. The set of prediction modes may comprise, for example, intra prediction modes and/or inter prediction modes.

Internal prediction

The set of intra prediction modes may contain 35 different intra prediction modes, e.g., non-directional modes such as DC (or average) mode and planar mode, or directional modes, such as those defined in HEVC, or may contain 67 different intra prediction modes, e.g. non-directional modes such as DC (or average) mode and planar mode, or directional modes such as those defined in VVC.

The intra prediction block 254 is configured to use reconstructed discrete samples of adjacent blocks of the same current image to generate an intra prediction block 265 in accordance with an intra prediction mode of a set of intra prediction modes.

The intra prediction block 254 (or more generally the mode selector 260) is further configured to output intra prediction parameters (or more generally information indicating the selected intra prediction mode for the block) to the entropy encoding block 270 in the form of syntax elements 266 for including an image in the encoded data 21 so that, for example, the video decoder 30 can receive and use the prediction parameters for decoding.

External prediction

The set of (possible) inter prediction modes depends on the available reference pictures (i.e., previous, at least partially decoded pictures, such as those stored in DBP 230) and other inter prediction parameters, such as whether the entire reference picture is used or only a portion, such as a search window area around the region of the current block, a reference image to find the most suitable reference block and/or, for example, whether pixel interpolation, such as half/semi-pel and/or quarter-pel interpolation, is applied or not.

In addition to the above prediction modes, a skip mode and/or a direct mode may be used.

The inter-prediction block 244 may include a Motion Estimation (ME) block and a Motion Compensation (MC) block (both not shown in FIG. 2). The motion estimator may be configured to receive or obtain an image block 203 (current image block 203 of the current image 17) and a decoded image 231, or at least one or more previously reconstructed blocks, such as reconstructed blocks of one or more different/different previously decoded ones. 231 images for motion estimation. For example, the video sequence may comprise the current image and previously decoded images 231 or, in other words, the current image and previously decoded images 231 may be part of or form a sequence of images making up the video sequence.

The encoder 20 may, for example, be configured to select a reference block from a plurality of reference blocks of the same or different images from a plurality of other images and provide a reference image (or reference image index) and/or an offset (spatial offset) between the position (x, y coordinates ) of the reference block and the position of the current block as inter-prediction parameters to the motion estimation block. This displacement is also called motion vector (MV).

The motion compensation unit is configured to obtain, for example, receive, an inter prediction parameter and perform inter prediction based on or using the inter prediction parameter to obtain an inter prediction unit 265. The motion compensation performed by the motion compensation block may include obtaining or generating a prediction block based on a motion vector/block determined by motion estimation, possibly performing interpolations with sub-pixel accuracy. Interpolation filtering can generate additional pixel samples from known pixel samples, thereby potentially increasing the number of candidate prediction blocks that can be used to encode an image block. After receiving the motion vector for the PU block of the current image, the motion compensation block may locate the prediction block pointed to by the motion vector in one of the reference picture lists.

The motion compensation block may also generate syntax elements associated with video blocks and slices for use by video decoder 30 when decoding image blocks of a video slice. In addition to or as an alternative to slices and corresponding syntactic elements, groups of tiles and/or tiles and corresponding syntactic elements may be formed or used.

Entropy coding

The entropy encoding block 270 is configured to employ, for example, an entropy encoding algorithm or scheme (e.g., a variable length coding (VLC) scheme, a context adaptive VLC (CAVLC) scheme, an arithmetic encoding scheme, binarization, a context adaptive binary arithmetic encoding ( CABAC) based on the syntax of context adaptive binary arithmetic coding (SBAC), probability interval entropy encoding (PIPE) or other entropy encoding method or methodology) or bypass (uncompressed) with respect to quantized coefficients 209, inter prediction parameters, parameters intra prediction, loop filter parameters, and/or other syntax elements to obtain encoded image data 21, which may be output via output 272, for example in the form of an encoded bitstream 21, so that, for example, video decoder 30 can receive and use these parameters for decoding, . The encoded bitstream 21 may be transmitted to video decoder 30 or stored in memory for later transmission or retrieval by video decoder 30.

Other changes to the structure of video encoder 20 may be used to encode the video stream. For example, non-transform encoder 20 may quantize the residual signal directly without transform processing unit 206. In another implementation, encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined into a single unit.

Decoder and decoding method

Fig. 3 shows an example of a video decoder 30 that is configured to implement the methods of the present application. Video decoder 30 is configured to receive encoded image data 21 (e.g., encoded bitstream 21), such as encoded by encoder 20, to obtain a decoded image 331. The encoded image data or bitstream contains information for decoding the encoded image data, e.g., data that represents blocks images of the encoded video slice (and/or tiles or groups of tiles) and associated syntactic elements.

In the example in FIG. 3, the decoder 30 includes an entropy decoding block 304, an inverse quantization block 310, an inverse transform processing block 312, a recovery block 314 (eg, adder 314), a loop filter 320, a decoded image buffer (DPB) 330, a mode applying block 360, a block 344 inter prediction and intra prediction block 354. The inter prediction unit 344 may be or include a motion compensation unit. Video decoder 30 may, in some examples, perform a decoding step that is generally the reverse of the encoding step described with respect to video encoder 100 in FIG. 2.

As described with respect to the encoder 20, the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded image buffer (DPB) 230, the inter-prediction unit 344, and the intra-prediction unit 354 also relate to forming the “embedded decoder”. " video encoder 20. Accordingly, the inverse quantization block 310 may be identical in function to the inverse quantization block 110, the inverse transform processing block 312 may be identical in function to the inverse transform processing block 212, the restoration block 314 may be identical in function to the reconstruction block 214, loop filter 320 may be identical in function to loop filter 220, and decoded image buffer 330 may be identical in function to decoded image buffer 230. Therefore, the explanations provided for the corresponding blocks and functions of the video encoder 20 apply correspondingly to the corresponding blocks and functions of the video decoder 30.

Entropy Decoding

Entropy decoding unit 304 is configured to parse bitstream 21 (or generally encoded image data 21) and perform, for example, entropy decoding on encoded image data 21 to obtain, for example, quantized coefficients 309 and/or decoded encoding parameters (not shown in FIG. 3), e.g., any or all of the inter prediction parameters (e.g., reference picture index and motion vector), intra prediction parameter (e.g., index or intra prediction mode), transform parameters, quantization parameters, contour parameters filter and/or other syntactic elements. The entropy decoding block 304 may be configured to apply decoding algorithms or schemes corresponding to the encoding schemes as described with respect to the entropy encoding block 270 of the encoder 20. The entropy decoding block 304 may be further configured to provide inter prediction parameters, an intra prediction parameter, and/or or other syntax elements to block 360 for applying the mode and other parameters to other blocks of prediction decoder 30. Video decoder 30 may receive syntax elements at the video slice level and/or video block level. In addition to or as an alternative to slices and corresponding syntax elements, groups of tiles and/or tiles and corresponding syntax elements may be received and/or used.

Inverse quantization

The inverse quantization unit 310 may be configured to receive quantization parameters (QPs) (or, more generally, information related to inverse quantization) and quantized coefficients from the encoded image data 21 (e.g., by parsing and/or decoding, e.g., by entropy decoding block 304) and applying, based on the quantization parameters, inverse quantization on the decoded quantized coefficients 309 to obtain dequantized coefficients 311, which may also be referred to as transform coefficients 311. The inverse quantization process may include using a quantization parameter determined by video encoder 20 for each video block in a video slice (or tile or group of tiles) to determine the degree of quantization and, likewise, the degree of inverse quantization to be applied.

Reverse conversion

The inverse transform processing unit 312 may be configured to receive the dequantized coefficients 311, also referred to as transform coefficients 311, and apply a transform to the dequantized coefficients 311 to obtain reconstructed residual blocks 213 in the sample region. The reconstructed residual blocks 213 may also be referred to as transform blocks 313. The conversion may be an inverse transform, such as an inverse DCT, an inverse DST, an integer integer transform, or a conceptually similar inverse transform process. The inverse transform processing unit 312 may be further configured to receive transform parameters or corresponding information from the encoded image data 21 (e.g., by parsing and/or decoding, such as through an entropy decoding unit 304) to determine a transform to be applied to dequantized coefficients 311.

Recovery

A reconstruction block 314 (e.g., an add block or an adder 314) may be configured to add the reconstructed residual block 313 with a prediction block 365 to obtain a reconstructed block 315 in the sample domain, for example by adding the sample values of the reconstructed residual block 313 and the sample values of the block 365 predictions.

Filtration

A loop filter block 320 (either in the encoding loop or after the encoding loop) is configured to filter the reconstructed block 315 to produce a filtered block 321, for example, to smooth pixel transitions or otherwise improve video quality. Loop filter block 320 may include one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or one or more other filters, such as a two-way filter, an adaptive loop filter (ALF), anti-aliasing filters, enhancement filters, etc. sharpening or joint filters, or any combination of them. Although the loop filter block 320 is shown in FIG. 3 as a loop filter, in other configurations the loop filter block 320 may be implemented as a post-loop filter.

Decoded Image Buffer

The decoded video blocks 321 of pictures are then stored in a decoded picture buffer 330, which stores the decoded pictures 331 as reference pictures for subsequent motion compensation for other pictures and/or for display output, respectively.

The decoder 30 is configured to output the decoded image 311, for example, through an output 312 for presentation or viewing to a user.

Prediction

The inter prediction block 344 may be identical to the inter prediction block 244 (in particular, the motion compensation block), and the intra prediction block 354 may be identical to the inter prediction block 254 in function, and makes splitting or splitting decisions and performs prediction based on the splitting parameters and /or prediction or related information received from the encoded image data 21 (eg, by parsing and/or decoding, eg, by entropy decoding unit 304). The mode application block 360 may be configured to perform prediction (intra or inter prediction) for each block based on the reconstructed images, blocks, or corresponding samples (filtered or unfiltered) to obtain a prediction block 365.

When a video slice is encoded as an intra-encoded (I) slice, an intra prediction block 354 of a mode applying block 360 is configured to generate a prediction block 365 for an image block of the current video slice based on the signaled intra prediction mode and data from previously decoded current image blocks. When a video image is encoded as an inter-encoded (i.e., B or P) slice, an inter-prediction block 344 (e.g., a motion compensation block) of the mode applying block 360 is configured to create prediction blocks 365 for the video block of the current video slice based on motion vectors and other syntax elements received from entropy decoding unit 304. For inter-prediction, prediction blocks may be created from one of the reference pictures within one of the reference picture lists. Video decoder 30 may construct reference picture lists, List 0 and List 1, using default construction methods based on reference pictures stored in DPB 330. The same or similar may be used for or through embodiments using groups of tiles (e.g., groups video tiles) and/or tiles (e.g., video tiles) in addition to or alternatively to slices (e.g., video slices), for example, the video may be encoded using groups I, P, or B of tiles and/or tiles .

The mode applying unit 360 is configured to determine prediction information for a video block of the current video slice by parsing motion vectors or related information and other syntax elements, and uses the prediction information to create prediction blocks for the current video block to be decoded. For example, mode apply block 360 uses some of the received syntax elements to determine the prediction mode (e.g., intra or inter prediction used to encode video slice video blocks, type of inter prediction slice (e.g., B-slice, P-slice, or GPB slice), construction information for one or more reference picture lists for a slice, motion vectors for each inter-coded video block of the slice, inter-prediction status for each inter-coded video block of the slice, and other information for decoding video blocks in the current video slice. The same or similar may. apply to or through embodiments using tile groups (e.g., video tile groups) and/or tiles (e.g., video tiles) in addition to or alternatively to slices (e.g., video slices, e.g., video may be encoded with using groups I, P or B of tiles and/or tiles.

Embodiments of video decoder 30, as shown in FIG. 3 may be configured to divide and/or decode an image using slices (also referred to as video slices), wherein the image may be divided into or decoded using one or more slices (usually non-overlapping), and each slice may contain one or more blocks (for example, CTU).

Embodiments of video decoder 30 shown in FIG. 3 may be configured to divide and/or decode an image using tile groups (also called video tile groups) and/or tiles (also called video tiles), wherein the image may be divided into or decoded using one or more groups of tiles (typically non-overlapping), and each group of tiles may comprise, for example, one or more blocks (eg, CTUs) or one or more tiles, wherein each tile, for example, may have a rectangular form and may contain one or more blocks (eg, CTUs), such as full or partial blocks.

Other embodiments of the video decoder 30 may be used to decode the encoded image data 21. For example, decoder 30 may produce an output video stream without loop filter block 320. For example, the non-transform decoder 30 may perform inverse quantization of the residual signal directly without the inversion processing block 312 for certain blocks or frames. In another implementation, video decoder 30 may have an inverse quantization block 310 and an inverse transform processing block 312 combined into one block.

It should be understood that in the encoder 20 and decoder 30, the result of processing of some current stage may be further processed and then output to the next stage. For example, after interpolation filtering, motion vector acquisition, or contour filtering, an additional operation such as Clip or offset may be performed on the result of the interpolation filtering, motion vector acquisition, or contour filtering processing.

It should be noted that additional operations may be applied to the resulting current block motion vectors (including, but not limited to, affine mode checkpoint motion vectors, affine mode subblock motion vectors, planar mode motion vectors, ATMVP mode motion vectors, temporary motion vectors, and the like). For example, the value of a motion vector is limited to a predetermined range according to its representing bit. If the representing bit of the motion vector is bitDepth, then the range is -2^(bitDepth-1) ~ 2^(bitDepth-1)-1, where "^" means exponentiation. For example, if bitDepth is 16, the range is -32768~32767; if bitDepth is 18, the range is -131072~131071. For example, the value of the resulting motion vector (eg, the MV of four 4x4 subblocks in one 8x8 block) is limited such that the maximum difference between the entire portions of the MV of the four 4x4 subblocks is no more than N pixels, eg, no more than 1 pixel. Here are two ways to constrain the motion vector according to bitDepth.

Method 1: Removing MSB (Most Significant Bit) Overflow via Streaming Operations

ux= ( mvx+2bitDepth ) % 2bitDepth (1)

mvx = ( ux >= 2bitDepth-1 ) ? (ux − 2bitDepth ): ux (2)

uy= ( mvy+2bitDepth ) % 2bitDepth (3)

mvy = ( uy >= 2bitDepth-1 ) ? (uy − 2bitDepth ): uy (4)

where mvx represents the horizontal component of the motion vector of the image block or sub-block, mvy represents the vertical component of the motion vector of the image block or sub-block, and ux and uy indicate an intermediate value;

For example, if the value of mvx is -32769, after applying formulas (1) and (2), the resulting value is 32767. In a computer system, decimal numbers are stored as two's complement. The two's complement for -32769 is 1,0111,1111,1111,1111 (17 bits), then the MSB is discarded, so the resulting two's complement is 0111,1111,1111,1111 (decimal is 32767), which is the same as the output from the application of formulas (1) and (2).

ux= ( mvpx + mvdx +2bitDepth ) % 2bitDepth (5)

mvx = ( ux >= 2bitDepth-1 ) ? (ux − 2bitDepth ): ux (6)

uy= ( mvpy + mvdy +2bitDepth ) % 2bitDepth (7)

mvy = ( uy >= 2bitDepth-1 ) ? (uy − 2bitDepth ): uy (8)

Operations can be applied during the summation of mvp and mvd, as shown in formulas (5) to (8).

Method 2: Remove MSB overflow by truncating the value

vx = Clip3(-2bitDepth-1, 2bitDepth-1 -1, vx)

vy = Clip3(-2bitDepth-1, 2bitDepth-1 -1, vy)

where vx represents the horizontal component of the motion vector of the image block or sub-block, vy represents the vertical component of the motion vector of the image block or sub-block; x, y and z respectively correspond to the three input values of the MV clipping process, and the definition of the Clip3 function is as follows:

Clip3( x, y, z ) =

Fig. 4 is a schematic diagram of a video encoding apparatus 400 according to an embodiment of the present disclosure. Video encoding apparatus 400 is suitable for implementing the disclosed embodiments that are described herein. In an embodiment, video encoding device 400 may be a decoder, such as video decoder 30 of FIG. 1A, or an encoder such as video encoder 20 of FIG. 1A.

The video encoding device 400 includes input ports 410 (or input ports 410) and receiver (Rx) blocks 420 for receiving data; a processor, logical unit, or central processing unit (CPU) 430 for processing data; transmitter (Tx) blocks 440 and output ports 450 (or output ports 450) for data transmission; and a memory 460 for storing data. Video encoding device 400 may also include optical-to-electrical (OE) components and electrical-to-optical (EO) components connected to input ports 410, receiver blocks 420, transmitter blocks 440, and output ports 450 to provide optical or optical input or output. electrical signals.

The processor 430 is implemented in hardware and software. Processor 430 may be implemented as one or more CPU chips, cores (eg, a multi-core processor), FPGA, ASIC, and DSP. Processor 430 communicates with input ports 410, receiver units 420, transmitter units 440, output ports 450, and memory 460. Processor 430 includes an encoding module 470. Encoding module 470 implements the disclosed embodiments described above. For example, encoding module 470 implements, processes, prepares, or provides various encoding operations. Therefore, turning on the encoding module 470 provides a significant improvement in the functionality of the video encoding device 400 and allows the video encoding device 400 to be transformed into a different state. Alternatively, encoding module 470 is implemented as instructions stored in memory 460 and executed by processor 430.

Memory 460 may include one or more disks, tape drives, and solid-state drives and may be used as an overflow storage device for storing programs when such programs are selected for execution and for storing instructions and data that are read during execution of the programs. Memory 460 may be, for example, volatile and/or non-volatile and may be read only memory (ROM), random access memory (RAM), ternary memory associative memory (TCAM), and/or static random access memory (SRAM).

Fig. 5 is a simplified block diagram of a device 500 that can be used as one or both of the source device 12 and the destination device 14 of FIG. 1 according to an exemplary embodiment .

The processor 502 in the device 500 may be a central processing unit. Alternatively, processor 502 may be any other type of device or plurality of devices capable of manipulating or processing information that currently exists or will be developed in the future. Although the disclosed implementations may be practiced with a single processor, as shown, for example, with processor 502, speed and efficiency benefits may be achieved by using more than one processor.

Memory 504 in device 500 may be read-only memory (ROM) or random access memory (RAM) in an implementation. Memory 504 may be any other suitable type of storage device. Memory 504 may include code and data 506 accessed by processor 502 using bus 512. Memory 504 may further include an operating system 508 and application programs 510, wherein application programs 510 include at least one program which allows the processor 502 to perform the methods described herein. For example, application programs 510 may include applications 1 through N, which further include a video encoding application that performs the methods described herein.

Device 500 may also include one or more output devices, such as a display 518. The display 518 may be, in one example, a touch display that combines a display with a touch element capable of sensing touch input (touch). Display 518 may be coupled to processor 502 via bus 512.

Although depicted here as a single bus, bus 512 of device 500 may be composed of multiple buses. In addition, secondary storage 514 may be directly coupled to other components of device 500 or may be accessible over a network and may comprise a single plug-in unit, such as a memory card, or multiple units, such as multiple memory cards. Thus, device 500 can be implemented in a wide variety of configurations.

At the 14th meeting of JVET, held in Geneva, JVET-N0217 was adopted: Affine Linear Weighted Internal Prediction (ALWIP) Adopted.

ALWIP introduces three new sets of indoor modes. They are:

35 modes for 4x4 blocks.

19 modes for 8x4, 4x8 and 8x8 blocks.

11 modes for other cases where the width and height are less than or equal to 64 samples.

Accordingly, the block size type variable (sizeId) is defined in ALWIP as follows:

If the block size is 4x4, the sizeId type of the block size is 0.

Otherwise, if the block size is 8x4, 4x8, or 8x8, the sizeId type of the block size is 1.

Otherwise, if the block size is not specified above and the block's width and height are less than 64, the size of the block's sizeId type is 2.

These modes generate an internal luminance prediction signal from a single row of reference samples to the left and above the current block by multiplying the matrix vector and adding an offset. For this reason, affine linear weighted intra prediction is also called matrix-based intra prediction (MIP). In the following text, the terms MIP and ALWIP are used interchangeably and both describe the JVET-N0217 tool.

To predict samples of a rectangular block of width W and height H, affine linear weighted intra prediction (ALWIP) takes as input one row of H reconstructed neighboring boundary samples to the left of the block and one row of W reconstructed neighboring boundary samples above the block. If reconstructed samples are not available, they are generated as in normal internal prediction.

The generation of the prediction signal is based on the following three steps:

1. From the boundary samples, four samples in the case of W=H=4 and eight samples in all other cases are extracted by averaging.

2. Perform matrix-vector multiplication followed by bias addition, with the averaged samples as input. The result is a reduced prediction signal for the subsampled set of samples in the original block.

3. The prediction signal at the remaining positions is generated from the prediction signal on the subsampled set using linear interpolation, which is a one-step linear interpolation in each direction.

The entire process of averaging, matrix-vector multiplication and linear interpolation is illustrated for various shapes in Fig. 6-9. Note that the remaining shapes are processed as in one of the cases depicted.

Fig. 6 illustrates the process for a 4x4 block. For block ALWIP takes two averages along each boundary axis. The resulting four input samples enter a matrix vector multiplication. Matrices are taken from the set . After adding bias, this gives 16 final prediction samples. Linear interpolation is not required to generate a prediction signal. Thus, only multiplication by sample.

Fig. 7 illustrates the process for the block . For an 8x8 block, ALWIP takes four averages along each boundary axis. The resulting eight input samples go into the vector multiplication matrix. Matrices are taken from the set . This gives 16 samples at odd positions of the prediction block. Thus, only ( multiplication by sample. After adding offset, these samples are interpolated vertically using the reduced upper bound. This is followed by horizontal interpolation using the original left boundary. Thus, only 2 multiplications per sample are required to calculate the ALWIP forecast.

Fig. 8 illustrates the process for the block . For an 8x4 block, ALWIP takes the four average values along the horizontal axis of the boundary and the four original boundary values on the left boundary. The resulting eight input samples go into the vector multiplication matrix. Matrices are taken from the set . This gives 16 samples at the odd horizontal and every vertical position of the prediction block. Thus, only ( multiplication by sample. After adding offset, these samples are interpolated horizontally using the original left boundary. Thus, only 4 multiplications per sample are required to calculate the ALWIP forecast.

The transposed case is handled accordingly.

Fig. 9 illustrates the process for a 16x16 block. For block ALWIP takes four averages along each boundary axis. The resulting eight input samples go into the vector multiplication matrix. Matrices are taken from the set . This gives 64 samples at odd positions of the prediction block. Thus, only ( multiplication by sample. After adding offset, these samples are interpolated vertically using the eight upper bound averages. This is followed by horizontal interpolation using the original left boundary. Thus, only two multiplications per sample are required to calculate the ALWIP forecast.

For large forms the procedure is essentially the same, and it is easy to verify that the number of multiplications per sample is less than four.

For blocks With Only horizontal interpolation is necessary since samples are given at odd horizontal and every vertical positions. In this case, to calculate the reduced (shortened) prediction, ( multiplications per sample. For the number of additional multiplications per sample required for linear interpolation is less than two. Thus, the total number of multiplications per sample is less than or equal to four.

Finally, for the blocks With , let is the matrix that results from eliminating each row that corresponds to an odd entry along the horizontal axis of the downsampled block. Thus, the output size is 32, and again only horizontal interpolation remains to be done. To calculate the reduced prediction, perform multiplications per sample. For no additional multiplications are required, while for Linear interpolation requires less than 2 multiplications per sample. Thus, the total number of multiplications per sample is less than or equal to four.

Transposed cases are handled accordingly.

In message JVET-N0217, the Most Probable Mode (MPM) list approach is also used for intra-MIP encoding. For current blocks, two MPM lists are used:

1. When the current block is using normal internal mode (i.e. not internal MIP mode), the 6-MPM list is used

2. When the current block uses internal MIP mode, the 3-MPM list is used

Both of the above MPM lists are built based on the intra prediction modes of their neighboring blocks, so the following cases may arise:

1. The current block is normally intra-predicted while one or more of its neighboring blocks/blocks has MIP intra-prediction applied, or

2. MIP intra prediction is applied to the current block, while normal intra prediction is applied to one or more of its neighboring blocks/blocks.

Under such circumstances, neighboring intra prediction modes are inferred indirectly using lookup tables.

In one example, when the current block is normally intra-predicted while its above block (A), as shown in FIG. 13 applies with internal MIP prediction, Data</GipSegment>

The following correspondence table 1 is used. Based on the block size types of the actual block above and the MIP intra prediction mode of the block above, a normal intra prediction mode is derived. Likewise, if the left (L) block shown in FIG. 13 is applied with MIP intra prediction, based on the block size types of the left block and the MIP intra prediction mode of the left block, the normal intra prediction mode is output.

Table 1. Description of the correspondence between affine linear weighted intra prediction and intra prediction modes

IntraPredModeY[ xNbX ][ yNbX ] block size type, sizeId 0 1 2 0 0 0 1 1 18 1 1 2 18 0 1 3 0 1 1 4 18 0 18 5 0 22 0 6 12 18 1 7 0 18 0 8 18 1 1 9 2 0 50 10 18 1 0 eleven 12 0 12 18 1 13 18 0 14 1 44 15 18 0 16 18 50 17 0 1 18 0 0 19 50 20 0 21 50 22 0 23 56 24 0 25 50 26 66 27 50 28 56 29 50 thirty 50 31 1 32 50 33 50 34 50

In one example, when the current block is applied with intra MIP prediction, and its aforementioned block (A), as shown in FIG. 14 is predicted using normal internal mode, the following correspondence table 2 is used. Based on the block size types of the actual upstream block and the normal intra prediction mode of the upstream block, the intra prediction mode MIP is derived. Likewise, if the left (L) block shown in FIG. 14 is applied with normal intra prediction, based on the block size types of the left block and the normal intra prediction mode of the left block, the intra prediction mode MIP is output.

Table 2. Description of the correspondence between intra prediction and affine linear weighted intra prediction modes

IntraPredModeY[ xNbX ][ yNbX ] block size type, sizeId 0 1 2 0 17 0 5 1 17 0 1 2, 3 17 10 3 4, 5 9 10 3 6.7 9 10 3 8, 9 9 10 3 10, 11 9 10 0 12, 13 17 4 0 14, 15 17 6 0 16, 17 17 7 4 18, 19 17 7 4 20, 21 17 7 4 22, 23 17 5 5 24, 25 17 5 1 26, 27 5 0 1 28, 29 5 0 1 30, 31 5 3 1 32, 33 5 3 1 34, 35 34 12 6 36, 37 22 12 6 38, 39 22 12 6 40, 41 22 12 6 42, 43 22 14 6 44, 45 34 14 10 46, 47 34 14 10 48, 49 34 16 9 50, 51 34 16 9 52, 53 34 16 9 54, 55 34 15 9 56, 57 34 13 9 58, 59 26 1 8 60, 61 26 1 8 62, 63 26 1 8 64, 65 26 1 8 66 26 1 8

In JEM, a secondary transform is applied between the forward primary transform and quantization (at the encoder) and between dequantization and the inverse primary transform (at the decoder side). As shown in FIG. 10, 4x4 (or 8x8) performs a secondary conversion depending on the block size. For example, the 4x4 secondary transform is applied to small blocks (i.e. min(width, height) < 8), and the 8x8 secondary transform is applied to large blocks (i.e. min(width, height) > 4) per 8x8 block.

The application of the inseparable transformation is described below using an input example. To apply an inseparable transformation, the input block is X 4x4

(1)

first represented as a vector :

(2)

The inseparable transformation is calculated as , Where indicates a vector of transformation coefficients, and T is a 16x16 transformation matrix. Vector The 16x1 coefficients are subsequently reorganized into a 4x4 block using the scan order for that block (horizontal, vertical, or diagonal). Coefficients with a lower index will be placed with a lower scan index into a 4x4 coefficient block. There are a total of 35 transformation sets and 3 inseparable transformation matrices (kernels) are used per transformation set. The mapping from (correspondence between) the intra prediction mode to the set of transformations is predetermined. For each set of transforms, the selected inseparable secondary transform candidate is further determined by an explicitly signaled secondary transform index. The index is transmitted in the bitstream once to the Intra CU after the conversion factors.

In VVC 5.0, Reduced Secondary Transform (RST) is adopted by offering JVET-N0193 as a new encoding tool with the following features.

The basic idea of the Reduced Transform (RT) is to map a vector of dimension N to a vector of dimension R in another space, where R/N (R <N) is the reduction factor.

The RT matrix is an R×N matrix of the following form:

where the R conversion strings are the R bases of the N-dimensional space. The inverse transform matrix for RT is the transpose of its forward transform. Forward and reverse RT are shown in Fig. eleven.

RST8×8 with reduction factor 4 (1/4 size) is used. Therefore, instead of 64x64, which is the usual size of an 8x8 matrix of an inseparable transformation, a direct 16x64 matrix is used. In other words, a 64x16 inverse RST matrix is used at the decoder side to generate the primary transform coefficients in the 8x8 upper left regions. Direct RST8x8 uses 16x64 matrices (or 8x64 for an 8x8 block), such that it produces non-zero coefficients only in the top left 4x4 region in a given 8x8 region. In other words, if RST is applied, then the 8x8 region, excluding the top left 4x4 region, will have only zero coefficients. For RST4x4, 16x16 (or 8x16 for a 4x4 block), direct matrix multiplication is applied.

Reverse RST is applied conditionally if the following two conditions are met:

The block size is greater than or equal to the specified threshold (W> = 4 && H> = 4);

The conversion skip mode flag is zero;

If both the width (W) and height (H) of the transform coefficient block are greater than 4, then RST8×8 is applied to the top left 8×8 region of the transform coefficient block. Otherwise, RST4×4 is applied to the upper left region of the min(8, W)×min(8, H) transform coefficient block.

If the RST index is 0, RST is not applied. Otherwise, RST is used, the kernel of which is selected with the index RST.

In addition, RST is applied to the internal CU in both the internal and intermediate slices, as well as Luma and Chroma. If dual tree is enabled, the RST indexes for Luma and Chroma are signaled separately . For intermediate slices (dual tree disabled), a single RST index is passed and used for both luma and chrominance.

Intra Sub-Partitions (ISP), like the intra prediction mode in VVC 4.0. When ISP mode is selected, RST is disabled and the RST index is not signaled because the performance improvement was negligible even if RST was applied to every possible partition block. Additionally, disabling RST for the ISP-predicted remainder can reduce encoding complexity.

The RST matrix is selected from four sets of transformations, each set of transformations containing two transformations. Which set of transformations is applied is determined from the intra prediction mode as follows:

If one of the three CCLM modes is specified (Cross-component linear model, in this mode the chrominance component is predicted from the luminance component), set 0 of transformations is selected.

Otherwise, the transformation set selection is performed according to the following table:

Table 3. Transformation set selection table

IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1

The index for accessing Table 3, IntraPredMode, has a range of [-14, 83], which is the converted mode index used for wide-angle intraprediction.

One example of a set of transformations is shown below.

The transform set index is 0, the 16x16 transform kernel is shown as follows

secTransMatrix [m][n] =

{

{ 108 -40 25 -32 8 -25 8 2 -16 -9 -13 8 -2 4 2 0 },

{ -{ -44 -97 -31 -39 -9 5 9 34 -27 -10 1 -7 13 9 -2 -2 },

{ -{ -15 56 -1 -92 33 16 16 -5 -39 -34 4 -5 -6 11 8 0 },

{ 1 12 7 51 -8 -3 1 1 -109 4 -9 -15 -4 31 -16 -10 },

{ -{ -44 -11 100 -6 -16 -38 37 -7 6 -9 -30 7 -2 4 8 -1 },

{ 19 29 -16 -16 -102 14 36 24 10 -5 -17 -30 28 9 5 -7 },

{ { 7 -12 -29 36 36 11 94 -25 16 -29 -3 -28 -13 16 28 -3 },

{ -1 -3 1 -8 23 -3 -38 -3 24 5 -64 -87 -14 19 -17 -35 },

{ -{ -11 18 -54 3 -4 -97 -7 8 3 -33 -35 31 -3 12 6 -1 },

{ 6 18 21 22 38 7 3 99 19 -26 11 4 37 33 -7 -7 },

{ { 2 -15 14 18 -27 26 -47 -28 10 -96 17 4 -15 32 18 -2 },

{ -1 -3 -4 -15 -5 1 11 -29 24 33 19 33 -3 94 -45 -32 },

{ 0 -1 -7 4 5 55 -6 6 -4 14 -86 61 -2 12 40 -6 },

{ -1 -3 2 1 16 -10 -13 -43 -7 4 6 -5 107 0 36 -33 },

{ -1 2 4 -5 -8 -19 -17 21 -2 39 36 -17 -36 34 97 -16 },

{ 0 1 0 2 -6 3 10 11 -3 -14 14 22 -24 -45 -8 -112 },

}

The transform set index is 1, the 16x16 transform kernel is shown as follows:

secTransMatrix [m][n] =

{

{ -111 -47 -35 13 -11 0 -17 4 5 -4 -2 5 -5 0 -1 -1 },

{ { 39 -27 -23 93 -27 -35 -46 -10 -20 -1 -10 13 -7 4 2 0 },

{ 4 15 4 -27 1 32 -92 -23 32 38 35 18 -34 -2 7 -12 },

{ 3 -1 4 -4 2 -2 14 4 -5 -18 -19 34 -83 -60 -57 23 },

{ { 44 -92 -17 -48 -47 26 7 16 8 -7 5 11 2 5 3 1 },

{ 11 43 -72 13 -4 60 -10 58 -3 -42 8 -4 -1 9 -7 -4 },

{ -{ -12 20 32 -34 -36 -3 -39 -17 -46 -63 -44 18 -4 42 9 17 },

{ -1 -2 6 4 10 -17 29 26 -7 -6 14 18 -73 34 68 -53 },

{ 7 20 -59 -52 -2 -82 -17 30 -4 33 -25 5 4 5 -9 -3 },

{ -{ -16 39 18 11 -85 1 27 21 2 34 25 58 20 -14 6 4 },

{ - { -5 -16 50 1 14 -30 -28 67 -15 -23 58 -3 15 9 -49 -21 },

{ 2 -5 -6 10 29 0 17 2 24 15 17 42 -12 80 -20 72 },

{ 3 10 0 3 -20 -37 1 -13 100 -65 7 -2 4 -5 6 -4 },

{ -1 -5 40 16 -2 21 -15 59 44 33 -84 -10 -3 13 -4 -8 },

{ { 4 -13 0 -3 57 3 -13 13 0 -20 -16 85 44 -38 36 -3 },

{ 2 2 -13 1 4 12 17 -40 5 2 -18 38 12 37 -64 -83 },

}

The transform set index is 2, the 16x16 transform kernel is shown as follows:

secTransMatrix [m][n] =

{

{ -112 29 -36 28 -12 18 5 -13 -4 15 -8 -2 -3 2 4 0 },

{ 47 -7 -87 -5 -24 53 -1 -32 -13 33 -24 -6 -7 6 8 1 },

{ -2 1 69 2 15 69 2 18 -10 63 -27 -24 -16 10 21 4 },

{ 2 -1 -10 -2 -3 -74 0 -2 19 89 15 13 -21 -3 40 11 },

{ -{ -34 -108 -17 -29 26 14 -26 15 18 8 12 -1 10 -5 -4 -2 },

{ 13 40 -33 13 80 24 6 34 46 15 41 -8 24 -16 -11 -4 },

{ 2 2 26 -2 -61 28 0 -27 60 25 26 37 46 -31 -28 -13 },

{ 0 0 -2 0 9 -30 1 7 -48 40 -29 -22 75 12 -57 -34 },

{ { 15 -45 7 103 15 -6 45 -25 16 -4 -17 3 8 7 5 3 },

{ -7 13 14 -36 54 -7 -9 -80 33 -8 -50 18 20 24 14 7 },

{ 1 4 -11 -4 -36 -11 -1 47 60 -15 -39 -51 38 41 31 20 },

{ 0 -1 2 1 2 12 0 -1 -48 -8 27 22 72 -16 70 47 },

{ 8 8 6 48 0 -5 -113 -16 1 -2 0 -23 1 -16 7 -6 },

{ -3 -5 8 -16 -4 -7 28 -50 0 -6 35 -95 2 -41 18 -19 },

{ -1 1 -7 -4 6 -6 8 28 5 -9 -67 17 1 -89 32 -42 },

{ 0 0 0 1 -2 8 -1 2 -2 -7 26 17 7 49 52 -101 },

}

The transform set index is 3, the 16x16 transform kernel is shown as follows:

secTransMatrix [m][n] =

{

{ -114 -19 36 -27 -11 15 13 16 -8 -6 5 -5 1 -3 -2 -5 },

{ { 37 -41 -25 -80 -21 47 25 11 -34 -30 9 -23 3 -2 -7 -12 },

{ 3 19 18 44 37 10 79 -26 -26 -42 -6 -23 23 -21 -33 -18 },

{ 2 -2 -2 -3 -10 -6 -39 13 7 -12 42 36 73 -52 -56 -12 },

{ -{ -22 85 -42 -58 44 -16 -13 -13 -26 -3 -15 3 8 1 -4 8 },

{ -{ -23 -60 -53 1 -4 -44 10 -74 -19 5 -18 22 5 -10 -6 22 },

{ { 14 -11 35 -29 47 42 31 -20 29 57 -9 36 34 -17 21 38 },

{ 0 7 5 19 -12 10 -4 -1 -37 -52 26 40 46 44 63 36 },

{ 21 17 46 -41 -37 -80 49 5 1 -2 15 27 -12 -19 15 -5 },

{ -{ -17 31 -60 18 -41 25 45 -6 22 37 58 -4 2 -20 31 -15 },

{ - { -5 -34 -25 -12 58 -40 12 29 46 -12 14 -16 35 30 32 -51 },

{ 2 2 19 -7 18 21 -8 -47 -9 6 43 56 -38 45 -22 -63 },

{ { 5 -11 8 12 10 -23 3 26 -81 74 23 -25 26 27 -10 -5 },

{ 2 19 21 -17 -46 -2 -1 -49 37 10 -10 -46 52 61 -26 0 },

{ -4 2 -33 7 -16 3 43 54 14 6 -37 56 2 49 -52 15 },

{ -1 -8 -1 -6 31 -14 7 2 20 -15 75 -24 -31 21 -38 73 },

}

The transform set index is 0, the 16x48 transform kernel is displayed as follows:

secTransMatrix [m][n] =

{

{ -117 -29 -10 -15 32 -10 1 0 -13 6 -12 0 -1 6 6 -1 },

{ { 28 -91 62 15 39 1 -33 6 -13 1 -2 -3 9 2 9 7 },

{ 18 47 -11 -10 92 50 -11 -6 -37 -14 -26 0 13 -3 -2 -2 },

{ 2 1 -8 -2 -44 -15 -14 21 -101 -36 -12 -4 5 2 35 9 },

{ 4 9 -2 1 4 2 7 -4 29 9 -9 -15 14 10 110 -11 },

{ 1 0 -2 0 -10 -3 -2 2 -11 -3 2 6 -2 -1 -22 5 },

{ 2 3 -1 1 1 1 2 0 8 2 -1 -3 2 2 11 -1 },

{ 1 0 -1 0 -4 -1 0 0 -3 0 1 1 -1 0 -4 1 },

{ { 32 -54 -95 10 26 -28 29 -20 -12 10 -3 -7 -8 8 -2 -7 },

{ -{ -18 26 3 112 12 -15 -12 -24 -15 9 30 -15 3 3 0 2 },

{ -2 -8 32 -20 -15 14 37 -104 -20 -18 4 -28 -4 -1 -3 -22 },

{ 0 3 0 -17 13 6 -7 30 2 -1 34 -86 -62 -20 1 4 },

{ -1 0 4 -4 -5 1 -4 5 -11 -3 -4 19 4 0 -18 -13 },

{ 0 1 0 -4 2 1 0 5 5 1 0 -5 1 1 12 0 },

{ 0 0 2 -1 -2 1 -1 1 -2 0 -1 4 1 0 -3 -1 },

{ 0 0 0 -2 0 0 0 2 1 0 0 -1 0 0 2 0 },

{ 14 33 32 -20 29 -99 6 -7 -12 38 -30 -5 -12 -4 -5 0 },

{ -1 5 -30 -26 -16 -4 -99 -46 10 26 3 -17 23 4 -4 28 },

{ -3 -9 -4 31 -22 9 3 10 26 -13 -92 -41 16 -16 -22 0 },

{ 0 -1 4 1 8 5 26 -14 12 -1 14 42 -11 0 8 76 },

{ -1 -2 -1 0 0 5 -1 7 -6 -5 19 -6 -17 -2 -25 4 },

{ 0 0 1 0 1 2 5 0 0 -1 0 2 0 0 3 -6 },

{ 0 -1 0 0 0 2 0 1 -1 -1 3 -1 -1 1 0 0 },

{ 0 0 0 0 1 1 2 0 0 0 0 1 0 0 0 -2 },

{ 2 -3 6 2 -20 44 14 9 -32 102 -11 -1 -11 34 -3 -13 },

{ 0 3 2 -16 6 -10 30 21 -2 3 34 -40 97 23 -21 5 },

{ 0 0 -5 -1 4 -11 -27 7 11 -14 21 37 -3 6 2 -76 },

{ 0 0 0 6 -3 1 -2 -6 3 -1 -33 13 -3 -7 -3 -4 },

{ 0 0 0 0 1 -2 1 -2 3 -5 1 -4 0 -4 9 33 },

{ 0 0 0 1 0 0 -1 -1 -1 -1 -2 2 -6 -2 -2 -1 },

{ 0 0 0 0 0 -1 0 0 1 -2 0 -1 0 -1 1 3 },

{ 0 0 0 0 0 0 -1 -1 0 0 -1 1 -2 0 0 0 },

{ 3 7 6 1 1 -5 -6 2 11 -29 -9 -10 -21 108 -7 9 },

{ 0 2 -3 -4 -4 4 6 2 -5 10 -4 13 -5 -5 1 18 },

{ -1 -2 0 0 -3 -3 6 5 -1 10 18 -1 23 -30 3 -3 },

{ 0 0 0 0 2 0 -3 -2 6 0 3 -4 0 6 -5 -35 },

{ 1 -1 2 0 -4 8 1 0 -4 10 2 4 2 -27 3 -4 },

{ 0 1 0 -3 1 -1 3 3 2 -4 0 -4 -2 10 0 -1 },

{ 0 0 -1 0 0 -2 -3 4 1 -1 0 3 -1 7 -1 6 },

{ 0 0 0 1 0 0 0 -1 0 1 -2 4 6 -2 0 1 },

{ 1 2 2 0 1 -2 -1 0 3 -7 -1 -2 -3 11 0 1 },

{ 0 1 -1 -1 -1 1 1 0 -1 1 -1 2 -3 -3 1 2 },

{ 0 -1 0 0 -2 -1 1 1 1 2 3 -1 1 -1 0 0 },

{ 0 0 0 0 1 0 0 0 2 1 0 -1 0 1 -1 -3 },

{ 1 0 1 0 -2 4 0 0 -1 2 0 1 0 -4 1 -1 },

{ 0 0 0 -2 0 0 1 1 0 -1 0 -1 0 1 0 0 },

{ 0 0 0 0 0 -1 -1 2 0 0 0 1 0 0 0 2 },

{ 0 0 0 0 0 0 0 -1 0 0 -1 2 2 1 0 0 },

}

The transform set index is 1, the 16x48 transform kernel is shown as follows:

secTransMatrix [m][n] =

{

{ 110 -43 -19 -35 9 -5 14 7 -13 -11 -4 -2 3 -4 5 -5 },

{ -{ -49 -19 17 -103 5 -5 17 35 -27 -13 -10 1 1 -8 -1 -6 },

{ -3 17 -7 39 -6 -28 27 17 -101 -3 -24 13 5 -1 26 -27 },

{ -4 -1 3 1 -1 9 -12 -4 24 -10 -11 -17 -15 -50 102 -22 },

{ -1 3 -2 7 -1 -3 1 -1 -8 3 3 3 1 6 -13 -12 },

{ -1 0 1 0 0 2 -3 0 6 -1 -2 -5 -2 -4 12 0 },

{ 0 1 -1 2 -1 -1 1 0 -3 1 0 1 1 2 -4 -3 },

{ -1 0 0 0 0 1 -1 0 2 0 -1 -2 -1 -2 4 0 },

{ -{ -38 -98 -32 38 42 -20 8 3 11 -19 -6 3 7 -1 -4 -5 },

{ -1 46 -59 -13 4 -78 19 8 43 -19 -37 0 4 5 -2 8 },

{ 10 14 29 25 21 22 -13 54 6 -37 -45 -55 -7 -22 -40 -20 },

{ 0 -1 3 -6 -11 16 4 -17 28 8 -17 22 29 20 -7 -83 },

{ 2 2 4 1 1 1 -2 1 -6 4 8 6 -1 6 -23 0 },

{ 0 0 0 -1 -3 3 1 -2 3 2 -2 1 2 1 3 0 },

{ 1 1 2 0 1 0 -1 1 -1 0 2 1 -1 0 -5 0 },

{ 0 0 0 0 -1 1 0 -1 1 1 -1 0 1 0 1 0 },

{ -9 26 -72 -1 21 80 48 10 -3 -12 17 8 8 -16 -1 9 },

{ 13 26 43 7 70 -6 -1 14 14 -30 14 74 3 -15 5 7 },

{ { 1 -15 34 6 -32 25 48 -11 21 3 -58 21 12 18 8 24 },

{ -2 -3 -9 -7 -21 -5 -15 -34 -12 -9 14 40 -14 -29 -23 -20 },

{ 0 -2 3 1 0 -4 -4 4 -7 5 15 -14 -9 -11 7 41 },

{ 0 -1 -2 -1 -4 -1 -2 -4 -2 0 0 0 -1 2 2 3 },

{ 0 -1 1 0 -1 -1 -1 1 -1 1 2 -2 -1 -2 1 6 },

{ 0 0 -1 0 -1 0 -1 -1 -1 0 0 0 0 1 1 1 },

{ -4 11 13 -13 34 6 1 -80 -23 -56 -10 -36 4 40 10 15 },

{ 2 -7 36 14 -26 -24 60 -7 10 -9 34 -8 29 -45 -11 20 },

{ -3 -9 -18 2 -57 7 -28 -6 -4 -47 -7 11 -15 -19 -13 12 },

{ 0 2 -10 -4 11 -9 -42 2 -12 8 28 -13 31 -22 -3 11 },

{ 0 0 0 2 4 0 5 15 3 21 4 -23 10 31 12 17 },

{ 0 0 -2 -1 2 0 -6 0 0 1 -1 1 4 2 -3 -9 },

{ 0 0 0 0 0 0 1 3 1 4 1 -3 1 4 2 1 },

{ 0 0 -1 0 1 0 -2 0 0 1 0 0 1 1 0 -2 },

{ -2 9 3 -2 -4 -7 11 -16 2 -11 23 -36 61 -25 -9 -26 },

{ 2 -3 0 11 -32 3 -11 46 9 -30 34 6 22 41 23 -1 },

{ 0 -1 -12 -6 5 13 -51 1 -10 10 -31 16 55 0 4 18 },

{ 1 2 3 -2 24 -4 11 3 0 59 4 -14 14 12 9 -1 },

{ -1 3 6 -2 1 -3 -2 2 1 -2 10 2 13 9 14 -12 },

{ 1 -3 1 4 -6 5 -10 7 -5 8 -22 19 3 7 9 32 },

{ 0 0 -3 -3 12 1 -2 -24 -4 41 -30 -4 -9 -42 -14 3 },

{ 0 0 2 0 4 -5 13 0 4 8 22 -12 -65 12 -4 -18 },

{ -1 4 1 0 -3 -2 2 2 2 2 4 -1 1 -3 0 -5 },

{ 1 -1 -1 3 -2 3 -6 -2 -2 5 -15 0 -11 -14 -12 10 },

{ 0 0 -2 -2 4 1 -4 -5 2 6 9 -7 -21 2 -7 -25 },

{ 0 0 0 0 -2 -2 4 8 2 -7 20 -3 -7 28 6 -5 },

{ -1 2 3 -1 0 -1 -2 1 0 -1 2 0 0 5 3 -2 },

{ 0 -1 1 1 -1 2 -3 -1 -2 3 -5 2 0 1 0 1 },

{ 0 0 -1 -1 0 -1 2 -2 1 5 9 -2 -1 6 6 -8 },

{ 0 0 1 0 0 -2 2 2 0 -2 4 -1 3 2 3 10 },

}

The transform set index is 2, the 16x48 transform kernel is shown as follows:

secTransMatrix [m][n] =

{

{ -121 0 -20 32 -3 -4 7 -8 -15 -3 -1 -5 -2 -2 -2 4 },

{ 33 -2 19 108 0 -12 1 -31 -43 1 -6 -14 0 -10 -3 -4 },

{ 4 0 -5 -43 -1 -3 2 14 -100 2 -3 -48 2 -4 -25 28 },

{ 4 0 2 10 0 1 0 -4 23 0 2 2 0 0 -2 103 },

{ 1 0 -1 -9 0 -1 0 3 -12 0 -1 -5 0 0 -3 -42 },

{ 2 0 1 3 0 0 0 -1 6 0 0 1 0 0 0 24 },

{ 0 0 0 -3 0 0 0 1 -4 0 0 -2 0 0 -1 -9 },

{ 1 0 0 1 0 0 0 0 2 0 0 0 0 0 0 7 },

{ - { -1 121 16 4 -29 19 4 9 -6 -6 -6 10 -2 3 -1 1 },

{ - { -1 -23 3 19 11 105 3 43 -17 3 -35 24 0 11 -3 2 },

{ 1 -7 -2 -7 -2 -31 -2 0 -48 1 9 99 1 -1 -1 4 },

{ 0 -3 0 1 1 7 0 1 10 0 0 -17 0 -1 4 0 },

{ 0 -2 0 -1 0 -6 0 -1 -5 0 2 10 0 0 -2 3 },

{ 0 -1 0 0 0 1 0 0 2 0 0 -4 0 0 2 -1 },

{ 0 -1 0 0 0 -2 0 0 -1 0 0 3 0 0 0 0 },

{ 0 0 0 0 0 0 0 0 1 0 0 -1 0 0 1 0 },

{ 24 17 -120 11 12 9 22 -13 1 0 1 4 -1 -6 -7 -1 },

{ -5 1 14 -30 7 46 -8 -105 -5 3 -6 14 -1 -40 -8 0 },

{ -1 -2 8 9 -1 -6 1 17 19 -2 11 32 1 -15 -97 -9 },

{ -1 0 1 -2 0 0 -1 -2 -6 0 -2 0 -1 6 17 -42 },

{ 0 0 3 1 0 0 0 2 3 0 2 2 0 -2 -9 17 },

{ 0 0 1 -1 0 0 0 0 -1 0 0 0 0 1 3 -9 },

{ 0 0 1 0 0 0 0 0 1 0 1 1 0 0 -3 3 },

{ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 -2 },

{ { 5 -27 -18 0 -117 8 -28 -8 2 -20 -9 -4 -1 5 -8 -1 },

{ -1 4 -2 -8 12 -29 -9 -25 7 8 -100 0 -4 57 -26 1 },

{ 0 2 3 2 9 9 4 -3 15 -2 17 -39 2 -6 -61 -14 },

{ 0 0 0 0 1 -3 0 0 -3 0 -1 6 0 2 -1 6 },

{ 0 0 1 0 3 1 1 0 1 0 1 -4 0 0 -3 -4 },

{ 0 0 0 0 0 0 0 0 -1 0 0 1 0 0 -1 2 },

{ 0 0 0 0 1 0 0 0 0 0 0 -1 0 0 -1 -1 },

{ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 },

{ { 3 -12 17 -7 -32 -3 117 -7 4 30 -10 2 -8 1 2 -1 },

{ -1 2 -3 -1 -3 -19 -10 32 10 13 -63 -3 -2 -95 10 -2 },

{ 0 1 -1 2 3 3 -8 -5 5 -3 1 -4 -1 18 24 -4 },

{ 0 0 0 0 0 0 0 1 -1 0 2 0 1 -6 -7 4 },

{ 2 -5 6 -3 12 -4 32 -1 0 -116 -17 2 30 -10 5 0 },

{ -1 1 -1 -1 -2 -6 1 4 3 6 3 -2 4 -34 9 3 },

{ 0 0 -1 1 -1 1 -4 0 1 10 -4 -2 -4 -2 19 1 },

{ 0 0 0 0 0 0 0 0 0 0 0 0 1 0 -1 -1 },

{ 2 -1 2 -2 7 0 3 2 -2 -35 -1 0 -102 -4 0 0 },

{ -1 0 0 -2 0 0 1 -1 1 -5 9 0 4 17 1 2 },

{ 0 0 0 1 0 0 -1 0 2 4 -1 -1 8 -2 4 0 },

{ 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 -2 },

{ 1 -2 2 0 1 0 -3 1 -1 -3 3 0 -69 0 -2 2 },

{ 0 0 0 0 0 -1 1 0 1 -1 4 -1 -2 2 0 0 },

{ 0 0 0 0 0 0 0 -1 1 0 -1 -1 6 1 1 0 },

{ 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 },

}

The transform set index is 3, the 16x48 transform kernel is shown as follows:

secTransMatrix [m][n] =

{

{ -115 15 29 -36 -6 4 -20 4 12 5 -3 -1 10 4 2 3 },

{ 37 51 -22 -98 18 15 -7 29 13 20 -4 -3 -4 6 9 -3 },

{ { 9 -18 16 25 3 52 -43 1 10 90 -34 2 -6 14 13 12 },

{ 2 0 -6 5 -3 -13 4 26 2 -17 -12 19 12 53 37 84 },

{ 2 -3 3 4 -1 5 0 -5 -1 4 2 -2 5 -4 19 -12 },

{ 1 0 -2 1 0 -3 1 4 3 -3 -1 4 1 4 6 8 },

{ 1 -1 1 2 0 2 -1 -2 -1 2 -1 -1 1 0 2 -2 },

{ 0 0 -1 1 0 -1 1 1 1 -1 0 2 0 2 2 3 },

{ { 10 -95 -4 -59 -50 -17 -7 -17 17 6 5 9 11 0 -9 6 },

{ -{ -29 7 -80 11 -5 -45 35 -7 -2 66 25 3 -9 -1 -3 13 },

{ 8 34 12 -17 -38 16 0 -73 -46 8 11 -35 -12 -20 -9 50 },

{ 0 -3 15 1 12 24 12 6 12 28 43 22 -2 -13 -28 -1 },

{ 1 5 0 1 0 -2 -4 6 7 -7 -10 11 -7 3 -20 45 },

{ 0 -1 3 1 2 4 1 2 0 3 4 1 0 2 -4 1 },

{ 1 2 0 0 0 -1 -1 1 2 -1 -2 2 -1 -1 -3 7 },

{ 0 0 1 0 1 2 0 1 0 1 1 0 0 1 -1 0 },

{ 23 23 45 6 3 -87 -51 -5 16 29 23 -7 33 -3 1 -2 },

{ - { -8 -47 7 -13 67 -8 -2 21 -45 5 20 -65 -10 1 18 18 },

{ -8 1 -59 7 -7 -14 -57 -3 -9 -19 -40 -19 -4 -5 9 -22 },

{ 1 6 7 -3 -40 7 5 5 -53 12 12 -22 18 35 28 -37 },

{ -1 0 -2 0 3 8 15 -1 6 9 21 11 18 -16 24 -13 },

{ 0 1 1 0 -6 1 0 -3 1 -1 -3 4 -4 -6 6 14 },

{ 0 0 -1 0 1 2 4 0 1 1 4 2 4 -1 2 0 },

{ 0 1 0 0 -3 0 0 -1 0 0 -1 1 -1 -2 2 3 },

{ 3 8 -15 14 -12 23 7 -11 70 -10 25 -75 28 46 -20 1 },

{ 3 5 41 -4 -13 -35 39 2 16 14 -28 -18 -72 29 -5 -12 },

{ - { -2 -12 -3 -14 65 -6 5 -52 8 -1 -10 3 1 13 -25 -3 },

{ -1 0 -16 3 -3 -3 -55 -3 -4 -13 5 -1 -49 21 -33 2 },

{ 0 -1 2 -1 -10 1 1 27 -37 7 8 -10 15 37 -36 -15 },

{ 0 0 -3 0 0 1 -7 -2 1 0 6 2 2 -5 9 -8 },

{ 0 0 0 0 -1 0 1 5 -7 1 0 0 2 4 -2 1 },

{ 0 0 -1 0 0 0 -3 0 0 0 2 1 1 -1 2 -1 },

{ 4 3 1 2 9 2 1 0 -12 0 -4 2 56 -10 -13 19 },

{ 0 -3 0 8 -20 5 -10 27 29 -6 21 -35 -23 -53 42 14 },

{ 0 1 7 -3 -5 -17 41 8 3 13 -64 -27 22 -18 1 -4 },

{ -1 -1 -2 -5 22 0 2 -58 21 -4 -8 4 -1 8 57 -12 },

{ 1 2 -3 2 -2 3 4 2 4 0 -5 1 4 9 -22 -4 },

{ 1 1 6 0 0 -1 -3 -5 0 -4 19 8 -1 12 -2 5 },

{ 0 -2 1 0 0 -1 -2 25 5 1 10 -17 -15 -41 -25 17 },

{ 0 0 -2 0 -1 -5 3 3 -1 5 -48 -19 26 -25 -28 8 },

{ 2 1 0 0 2 0 -1 0 -3 0 3 3 6 -2 5 2 },

{ 0 -1 0 3 -3 1 -2 3 4 -1 -1 0 4 2 6 -4 },

{ 0 0 1 0 -2 -4 7 0 1 -1 10 3 -10 13 19 -4 },

{ 0 0 0 -1 3 0 1 -5 4 1 -3 -6 0 -16 -12 4 },

{ 0 1 -1 1 -1 1 1 0 2 0 0 0 0 4 -5 -2 },

{ 0 1 2 0 0 0 -1 -2 0 -1 4 2 2 1 -3 2 },

{ 0 -1 0 0 1 0 -1 7 1 0 3 -1 -3 -5 -2 1 },

{ 0 0 -1 0 0 -2 0 0 0 0 -6 -2 2 1 4 0 },

}

In the case of RST8x8 or RST4x4, in terms of counting, multiplication can occur when all TUs are 4x4 TU or 8x8 TU in size. Therefore, the top 8x64 and 8x16 matrices (in other words, the first 8 top transform basis vectors in each matrix) are applied to the 8x8 TU and 4x4 TU, respectively.

For blocks larger than 8x8 TU (width and height greater than 8), RST8x8 (i.e. 16x64 Matrix) is applied to the top left 8x8 region. For 8x4 TU or 4x8 TU, RST4x4 (i.e. 16x16 Matrix) is applied to the top left 4x4 region (in the example, RST 4x4 is not applied to other 4x4 regions). In case of 4xN or Nx4 TU (N ≥ 16), RST4x4 is applied to the two adjacent top left 4x4 blocks.

Given the above simplification, in some cases the number of multiplications is 8 per sample.

To reduce the size of the secondary transform matrix, 16x48 matrices are applied with the same transform set configuration, each 16x48 matrix taking 48 input samples from three 4x4 blocks in the top left 8x8 block (in the example below right 4x4 blocks excluded), as shown in Fig. 12.

VVC 5.0 introduces the MIP tool and the RST tool, and both tools are used for indoor blocks. However, both tools are not consistent in terms of the choice of secondary transformation kernel. In other words, since MIP is not a regular internal mode, which means that if one internal block is predicted using MIP mode, the way to select the RST transform kernel is not determined with both JVET-N0217 and JVET-N0193 proposals adopted. The following solutions resolve the above issue.

Fig. 15 illustrates a method according to the present disclosure. In fig. 15 illustrates an encoding method implemented by a decoding apparatus or an encoding apparatus. The decoding device may be a decoder 30 as described above. Likewise, the encoding device may be an encoder 20, as described above. In fig. 15, at step 1601, the method comprises determining an intra prediction mode of the current block. At a next step 1603, the method comprises determining a secondary transform selection of the current block based on the intra prediction mode determined for the current block. This is described in more detail below.

Fig. 16 illustrates an encoder 20 according to the present disclosure. In fig. 16, the encoder 20 includes a determination block 2001 configured to determine the intra prediction mode of the current block. The encoder 20 of FIG. 17 further shows a selector 2003 configured to determine a secondary transform selection of the current block based on an intra prediction mode determined for the current block.

Fig. 17 illustrates a decoder 30 according to the present disclosure. In fig. 17, the decoder 30 includes a determination unit 3001 configured to determine the intra prediction mode of the current block. The decoder 30 of FIG. 17 further shows a selector 3003 configured to determine a secondary transform selection of the current block based on an intra prediction mode determined for the current block.

In the following, the encoding method of FIG. 15 implemented by the decoding device or encoding device of FIG. 17 and 16, respectively, in more detail.

Solution 1

According to Solution 1, matrix-based intra prediction and reduced secondary transform are eliminated for the same intra prediction block.

In an example, when an intra-prediction block is predicted using the MIP mode (in the example, the value of the MIP flag can be used to indicate whether the block is predicted using the MIP mode or not), the secondary transform is disabled for that intra-prediction block, in other words, the secondary transform index value is set to 0, or the secondary transform index does not need to be decoded from the bitstream.

When an intra prediction block is not predicted using the MIP mode, a secondary transform transform kernel is selected based on the method mentioned in JVET-N0193.

Changes to the specification text compared to JVET-N0193 are highlighted in grey.

if (min(cbWidth, cbHeight)> = 4 && sps_st_enabled_flag == 1 && CuPredMode [ x0 ][ y0 ] = = MODE_INTRA
&& IntraSubPartitionsSplitType == ISP_NO_SPLIT && intra_mip_flag == 0) { if ((numSigCoeff> ((treeType == SINGLE_TREE)? 2 : 1 ) ) &&
numZeroOutSigCoeff == 0) { st_idx [x0][y0] ae(v) } }

7.4.3.1 RBSP Sequence Parameter Set Semantics

……

sps_st_enabled_flag equal to 1 indicates that st_idx may be present in the residual encoding syntax for inner encoding units. sps_st_enabled_flag equal to 0 indicates that st_idx is not present in the residual encoding syntax for inner encoding units.

……

7.4.7.5 Coding unit semantics

……

st_idx [ x0 ][ y0 ] indicates which secondary transform kernel is applied between two candidate kernels in the selected transform set. st_idx[x0][y0] equal to 0 indicates that no secondary conversion is applied. The array indices x0, y0 determine the position (x0, y0) of the top left sample of the transform block in question relative to the top left sample of the image.

intra_mip_flag [ x0 ][ y0 ] equal to 1 indicates that the intra prediction type for luma samples is affine linear weighted intra prediction. intra_lwip_flag[ x0 ][ y0 ] equal to 0 indicates that the intra prediction type for luma samples is not affine linear weighted intra prediction.

Solution 2

According to Solution 2, during the secondary transform kernel selection process, when a block is predicted using the MIP mode, one of the set of secondary transform kernels is considered to be used for that block.

In one embodiment

Transform set 0 is used as the selected set of secondary transform kernels when the current block is predicted in MIP mode.

The RST matrix is selected from four sets of transformations, each set of transformations containing two transformations. The set of transformations that is applied to the block is determined according to the intra prediction mode as follows:

If the current indoor block is predicted using CCLM mode, transform set 0 is selected;

Otherwise, if the current indoor block is predicted using MIP mode, transform set 0 is selected;

Otherwise (if the current indoor block is not predicted using CCLM or MIP mode), the transformation set selection is performed according to the following table:

Table 4. Transformation set selection table

IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1

The index range for IntraPredMode is -14 to 83 (including -14 and 83), which is the converted mode index used for wide-angle intra prediction.

In this solution, one transform set is used when the current block is predicted using MIP mode, transform set 0 is used in the example, other transform sets can also be used in this solution.

Solution 3

According to Solution 3, during the secondary transform kernel selection process, when a block is predicted using MIP mode, a trained set of secondary transform kernels is considered to be used for that block. The trained set of secondary transformation kernels may be different from the set of transformation kernels in the examples above.

In one embodiment:

Transformation set 4 (new trained) is used as the selected set of secondary transformation kernels when the current block is predicted in MIP mode.

Transform set 4 has the same dimensions as transform sets 0-3 (i.e. 16x16 and 16x48), which were trained based on the same machine learning method and MIP mode training set input.

The RST matrix is selected from four sets of transformations, each set of transformations containing two transformations. The set of transformations that is applied to the block is determined according to the intra prediction mode as follows:

If the current indoor block is predicted using CCLM modes, transform set 0 is selected;

Otherwise, if the current indoor block is predicted using the MIP mode, transform set 4 is selected;

Otherwise (if the current indoor block is not predicted using CCLM or MIP mode), the transformation set selection is performed according to the following table:

Table 5. Transformation set selection table

IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1

The index range for IntraPredMode is -14 to 83 (including -14 and 83), which is the converted mode index used for wide-angle intra prediction.

In this solution, a new trained set of transformations (for example, set 4 of transformations) is used when the current block is predicted using the MIP mode.

Solution 4

According to Solution 4, during the secondary transform kernel selection process, when a block is predicted using the MIP mode, a lookup table is used to map the MIP mode index to the regular internal mode index, then a set of secondary transform kernels is selected based on this regular internal mode index.

In one embodiment:

If the current block is predicted using the MIP mode, the MIP mode index is mapped to the normal internal mode index based on Table 6. In this example, Table 6 is the same as the MIP MPM mapping table.

Table 6. Description of the correspondence between affine linear weighted intra prediction and intra prediction modes

IntraPredModeY[ xNbX ][ yNbX ] block size type, sizeId 0 1 2 0 0 0 1 1 18 1 1 2 18 0 1 3 0 1 1 4 18 0 18 5 0 22 0 6 12 18 1 7 0 18 0 8 18 1 1 9 2 0 50 10 18 1 0 eleven 12 0 12 18 1 13 18 0 14 1 44 15 18 0 16 18 50 17 0 1 18 0 0 19 50 20 0 21 50 22 0 23 56 24 0 25 50 26 66 27 50 28 56 29 50 thirty 50 31 1 32 50 33 50 34 50

The selection of a set of secondary transformations is then made according to the following table:

Table 7. Transformation set selection table

IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1

For example, if the current block is predicted using a MIP mode index of 10, and the block size type sizeID value for the current block is 0, then the normal internal mode mapped index is 18 based on Table 6, and the secondary transform set 2 is selected based on Table 7.

This solution uses a mapping method from a MIP mode index to a regular internal mode index, when a block is predicted using the MIP mode, the selection of the secondary transformation kernel is based on the mapped regular internal mode index.

Fig. 18 is a block diagram showing a content delivery system 3100 for implementing a content distribution service. This content delivery system 3100 includes a capture device 3102, a terminal device 3106, and optionally includes a display 3126. The capture device 3102 communicates with the terminal device 3106 via a communication line 3104. The communication link may include a communication channel 13 described above. Communication link 3104 includes, but is not limited to, WIFI, Ethernet, cable, wireless (3G/4G/5G), USB, or any combination thereof, or the like.

The capture device 3102 generates data and can encode the data using the encoding method shown in the above embodiments. Alternatively, capture device 3102 may distribute the data to a streaming server (not shown in the Figures), and the server encodes the data and transmits the encoded data to terminal device 3106. Capture device 3102 includes, but is not limited to, a camera, smartphone, or tablet. , a computer or laptop, a video conferencing system, a PDA, a vehicle-mounted device, or a combination of any of these, or the like. For example, capture device 3102 may include source device 12 described above. When the data includes video, the video encoder 20 included in the capture device 3102 may actually perform video encoding processing. When the data includes audio (ie, speech), an audio encoder included in the capture device 3102 may actually perform audio encoding processing. For some practical scenarios, capture device 3102 distributes encoded video and audio data by multiplexing them together. For other practical scenarios, such as in a video conferencing system, encoded audio data and encoded video data are not multiplexed. The capture device 3102 distributes the encoded audio data and the encoded video data to the terminal device 3106 separately.

In the content delivery system 3100, the terminal device 310 receives and reproduces encoded data. The terminal device 3106 may be a device with ingest and retrieval capabilities, such as a smartphone or tablet 3108, a computer or laptop 3110, a Network Video Recorder (NVR)/Digital Video Recorder (DVR) 3112, a television 3114, a television set top box (STB) 3116, video conferencing system 3118, video surveillance system 3120, personal digital assistant (PDA) 3122, vehicle-mounted device 3124, or a combination thereof, or the like, capable of decoding the above encoded data. For example, terminal device 3106 may include receiver device 14 described above. When the encoded data includes video, the video decoder 30 included in the terminal device is given priority to perform video decoding. When the encoded data includes audio, an audio decoder included in the terminal device is given priority to perform audio decoding processing.

For a terminal device with its own display, such as a 3108 smartphone or tablet, 3110 computer or laptop, 3112 Network Video Recorder (NVR)/Digital Video Recorder (DVR), 3114 TV, 3122 Personal Digital Assistant (PDA), or 3124 vehicle-mounted device, terminal the device can transmit decoded data to its display. For a non-display terminal device, such as the STB 3116, video conferencing system 3118, or video surveillance system 3120, it communicates with an external display 3126 to receive and display the decoded data.

When each device in this system performs encoding or decoding, a picture encoding device or an image decoding device may be used, as shown in the above embodiments.

Fig. 19 is a diagram showing the structure of an exemplary terminal device 3106. After the terminal device 3106 receives a stream from the capture device 3102, a protocol processing unit 3202 analyzes the transmission protocol of the stream. The protocol includes, but is not limited to, Real Time Streaming Protocol (RTSP), Hypertext Transfer Protocol (HTTP), HTTP Live Streaming Protocol (HLS), MPEG-DASH, Real Time Transport Protocol (RTP), Exchange Protocol real-time messaging (RTMP) or any combination thereof, or the like.

After the protocol processing unit 3202 processes the stream, a stream file is generated. The file is output to a demultiplexing block 3204. A demultiplexer 3204 may separate the multiplexed data into encoded audio data and encoded video data. As described above, in other practical scenarios, such as in a video conferencing system, encoded audio data and encoded video data are not multiplexed. In this situation, the encoded data is transmitted to the video decoder 3206 and audio decoder 3208 without using the demultiplexer 3204.

Demultiplexing processing produces an Elementary Stream (ES) of video, ES audio, and optionally subtitles. The video decoder 3206, which includes the video decoder 30 described in the above embodiments, decodes the ES video using the decoding method as shown in the above embodiments to generate a video frame and supplies this data to the synchronization unit 3212. Audio decoder 3208 decodes ES audio to form an audio frame and supplies this data to synchronization unit 3212. Alternatively, the video frame may be stored in a buffer (not shown in FIG. 19) before being supplied to synchronization block 3212. Likewise, an audio frame may be stored in a buffer (not shown in FIG. 19) before being supplied to synchronization block 3212.

The synchronization unit 3212 synchronizes the video frame and the audio frame and supplies the video/audio to the video/audio display 3214. For example, the synchronization unit 3212 synchronizes the presentation of video and audio information. Information may be encoded in syntax using timestamps relating to the presentation of the encoded audio and video data, as well as timestamps relating to the delivery of the data stream itself.

If subtitles are included in the stream, subtitle decoder 3210 decodes the subtitles and synchronizes them with the video frame and audio frame and transmits the video/audio/subtitles to the video/audio/subtitle display 3216.

Mathematical operators

The mathematical operators used in this application are similar to those used in the C programming language. However, the results of integer division and arithmetic shift operations are defined more precisely, and additional operations such as exponentiation and real-valued division are also defined. Numbering and counting conventions specify starting at 0, for example, "first" is equivalent to 0, "second" is equivalent to 1, etc.

Arithmetic operators

The following arithmetic operators are defined as follows:

+ Addition − Subtraction (as a two-argument operator) or negation (as a unary prefix operator) * Multiplication, including matrix multiplication x ^y Exponentiation. Defines x to the power of y. In other contexts, this notation is used as a superscript that should not be interpreted as exponentiation. / Integer division with the result truncated towards zero. For example, 7/4 and -7/-4 are truncated to 1, and -7/4 and 7/-4 are truncated to -1. ÷ Used to indicate division in mathematical equations where truncation or rounding is not intended. Used to indicate division in mathematical equations where truncation or rounding is not intended. Summation f( i), where i takes all integer values from x to y inclusive. x % y Modulo operation. The remainder of x divided by y is defined only for integers x and y, where x >= 0 and y > 0.

Logical operators

The following logical operators are defined as follows:

x && y - Boolean logical "and" for x and y

x || y - Boolean logical "or" for x and y

! - Boolean logical "not"

x? y : z - If x is TRUE or not 0, the value of y is calculated; otherwise, the z value is calculated.

Relational operators

The following relational operators are defined as follows:

> - More

>= - Greater than or equal to

< - Less

<= - Less than or equal to

== - Equal

!= - Not equal

When a comparison operator is applied to a syntax element or variable that is assigned the value "na" (not applicable), the value of "na" is treated as a separate value for the syntax element or variable. The value "na" is not considered equal to any other value.

Bit operators

The following bitwise operators are defined as follows:

& - Bitwise "and". When operating on integer arguments, operates on the two's complement representation of an integer value. When working on a binary argument that contains fewer bits than another argument, the shorter argument is expanded by adding more significant bits equal to 0.

| - When operating on integer arguments, operates on the two's complement representation of an integer value. When working on a binary argument that contains fewer bits than another argument, the shorter argument is expanded by adding more significant bits equal to 0.

^ - When operating on integer arguments, operates on the two's complement representation of an integer value. When working on a binary argument that contains fewer bits than another argument, the shorter argument is expanded by adding more significant bits equal to 0.

x >> y - Arithmetic right shift of the two's complement integer representation of x by y binary digits. This function is defined only for non-negative integer values of y. The bits shifted to the most significant bits (MSB) by a right shift have a value equal to the MSB of x before the shift operation.

x << y - Arithmetic left shift of the two's complement integer representation of x by y binary digits. This function is defined only for non-negative integer values of y. Bits shifted to the least significant bits (LSB) by left shifting have a value of 0.

Assignment Operators

The following arithmetic operators are defined as follows:

= - Assignment operator

++ - Increment, i.e. x++ is equivalent to x = x+ 1; when used in an array index, it is calculated into the value of the variable before the increment operation.

−− - Decrement, i.e. x−− is equivalent to x = x- 1; when used in an array index, the value of the variable is calculated before the decrement operation.

+= - Increment by the specified amount, i.e. x+=3 is equivalent to x=x+3, and x+=(−3) is equivalent to x=x+(−3).

−= - Decrease by the specified amount, i.e. x−=3 is equivalent to x=x−3, and x−=(−3) is equivalent to x=x−(−3).

Range designation

The following notation is used to indicate a range of values:

x=y..zx takes integer values from y to z, inclusive, where x, y and z are integers and z is greater than y.

Mathematical functions

The following mathematical functions are defined:

Abs( x ) =

Asin(x) is a trigonometric arcsine function operating on an argument x that ranges from - to inclusive, with an output value ranging from -π÷2 to π÷2 inclusive, in units of radians.

Atan(x) is a trigonometric arctangent function operating on an argument x, with an output value ranging from - π÷2 to π÷2 inclusive, in units of radians.

Atan2(y,x) =

Ceil(x)

Clip1Y(x) = Clip3( 0, ( 1 << BitDepthY ) − 1, x )

Clip1C(x) = Clip3( 0, ( 1 << BitDepthC ) − 1, x )

Clip3(x,y,z) =

Cos(x) is a trigonometric cosine function that operates on x in units of radians.

Floor(x) is the largest integer less than or equal to x.

GetCurrMsb(a,b,c,d) =

Ln(x) natural logarithm of x (logarithm to base e, where e is the base constant of the natural logarithm 281 828...).

Log2(x)

Log10(x) logarithm of x to base 10.

Min(x,y)=

Max(x,y)=

Round(x)=Sign(x)*Floor(Abs(x)+)

Sign(x)=

Sin(x) is a trigonometric sine function that operates on x in units of radians.

Sqrt(x) =

Swap(x,y)=(y,x)

Tan(x) is a trigonometric tangent function that operates on x in units of radians.

Order of priority of operations

When the order of precedence in an expression is not explicitly specified using parentheses, the following rules apply:

- Higher priority operations are evaluated before any lower priority operation.

- Operations with the same priority are evaluated sequentially from left to right.

The table below lists the priority of operations from highest to lowest; a higher position in the table indicates higher priority.

For those operators that are also used in the C programming language, the order of precedence used in this description is the same as in the C programming language.

Table. Priority of operations from highest (at the top of the table) to lowest (at the bottom of the table)

operators (on operands x, y, and z) "x++", "x− −" "!x", "−x" (as unary prefix operator) x ^y "x * y", "x/y", "x ÷ y", " ", "x % y" "x + y", "x − y" (as an operator with two arguments), " " "x  <<  y", "x  >>  y" "x < y", "x <= y", "x > y", "x >= y" "x  =  =  y", "x  !=  y" "x&y" "x | y" "x  &&  y" "x  |  |  y" "x ? y : z" "x..y" "x = y", "x + = y", "x − = y"

Text description of logical operations

The text contains a definition of logical operations, which would be described mathematically in the following form:

if( condition 0 )

instructions 0

else if( condition 1 )

instruction 1

...

else /* informative comment on the remaining condition */

instruction n

can be described as follows:

... as below / ... the following applies:

- If condition 0, instruction 0

- Else, if condition 1, instruction 1

- ...

-- Otherwise (informative comment on the remaining condition), instruction n.

Each "If... Else, if... Else,..." expression in the text is introduced by the words "... as follows" or "... the following applies", immediately followed by "If..." . The last condition of "If... Else If... Otherwise, ..." is always "Else, ...". Alternating definitions "If... Else If... Otherwise, ..." can be identified by matching "... as follows" or "... the following applies" with the final "Else, ...".

The text contains a definition of logical operations, which would be described mathematically in the following form:

if( condition 0a && condition 0b )

instructions 0

else if( condition 1a | | condition 1b )

instruction 1

...

else instruction n

can be described as follows:

... as below / ... the following applies:

- If all of the following conditions are true, instruction 0:

- condition 0a

- condition 0b

-- Else, if one or more of the following conditions are true, definition 1:

- condition 1a

- condition 1b

- ...

- Otherwise, instruction n

The text contains a definition of logical operations, which would be described mathematically in the following form:

if( condition 0 )

instructions 0

if( condition 1 )

instruction 1

can be described as follows:

Condition 0, instruction 0

Condition 1, instruction 1.

Although embodiments of the present invention have been primarily described in terms of video encoding, it should be noted that embodiments of encoding system 10, encoder 20, and decoder 30 (and thus system 10), as well as other embodiments described herein, may also be configured to process or encode a still image, i.e. processing or encoding a single image independently of any preceding or subsequent image, as in video encoding. In general, only the inter prediction (encoder) and 344 (decoder) blocks 244 may not be available if the encoding for image processing is limited to a single image 17. All other functionality (also referred to as tools or techniques) of video encoder 20 and video decoder 30 may equally useful for still image processing, such as residual computation 204/304, transform 206, quantization 208, inverse quantization 210/310, (inverse) transform 212/312, division 262/362, intra prediction 254/354, and/or contour filtering 220, 320 and entropy encoding 270 and entropy decoding 304.

Embodiments of, for example, encoder 20 and decoder 30, as well as the functions described herein, for example, with respect to encoder 20 and decoder 30 may be implemented by hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a computer-readable medium or transmitted through a communication medium in the form of one or more instructions or code and executed by a hardware processing unit. Computer-readable media may include computer-readable media that corresponds to a tangible medium, such as a storage medium, or a communication medium, including any medium that enables transmission of a computer program from one location to another, such as according to a communications protocol. Thus, computer readable media may typically correspond to (1) tangible computer readable media that is durable, or (2) a communication medium such as a signal or carrier wave. Storage media can be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementing the methods described in this disclosure. The computer program product may include computer-readable media.

By way of example, and not limitation, such computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other media that can used to store desired program code in the form of instructions or data structures and can be accessed by a computer. Additionally, any connection is properly referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave communications, then coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwave communications are included in the definition of media. However, it should be understood that computer readable and storage media do not include connections, carrier waves, signals, or other short-lived media, but are instead directed to long-term, tangible storage media. The disk and disc used in this document include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where discs ) typically reproduce data magnetically, while discs (discs) reproduce data optically using lasers. Combinations of the above should also be included in the scope of computer readable media.

The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Accordingly, the term “processor” as used herein can refer to any of the above structure or any other structure suitable for implementing the methods described herein. Additionally, in some aspects, the functionality described herein may be provided within specialized hardware and/or software modules configured for encoding and decoding or included in a bundled codec. In addition, the methods may be implemented entirely in one or more circuits or logic elements.

The methods of this disclosure may be implemented in a wide variety of devices or hardware components, including a wireless phone, an integrated circuit (IC), or a set of ICs (eg, a chipset). This disclosure describes various components, modules, or blocks to highlight functional aspects of devices configured to implement the disclosed technologies, but not necessarily required to be implemented by different hardware units. Rather, as described above, the various blocks may be combined into a codec hardware block or provided by a collection of interacting hardware blocks, including one or more processors as described above, together with suitable software and/or firmware.

The present disclosure discloses the following additional aspects.

A first aspect of an encoding method implemented by a decoding apparatus or an encoding apparatus, comprising: selecting a secondary transform kernel for secondary transforming a current block based on an intra prediction mode index of the current block when the current block is not predicted using a matrix-based intra prediction mode, MIP.

A second aspect of the method according to the first aspect, wherein the method further comprises: disabling secondary mapping of the current block when the current block is predicted using the MIP mode.

A third aspect of the method according to the second aspect, wherein disabling the secondary conversion of the current block comprises: setting the value of the secondary conversion indication information for the current block to a default value.

A fourth aspect of the method according to any of the first to third aspects, in which whether the current block is predicted using the MIP mode or not is indicated according to the value of the MIP indication information.

A fifth aspect of an encoding method implemented by a decoding device or an encoding device, comprising: obtaining an intra prediction mode index of the current block according to the matrix-based intra prediction, MIP, mode index of the current block, and the size of the current block; selecting a secondary transform kernel to secondary transform the current block based on the intra prediction mode index of the current block.

The sixth aspect of the method according to the fifth aspect, in which the intra prediction mode index of the current block is obtained according to the mapping ratio among the MIP mode index, the size of the current block, the mapping ratio is specified according to a predetermined Table.

A seventh aspect of an encoding method implemented by a decoding apparatus or an encoding apparatus comprises: using a secondary transform kernel to secondary transform a current block when the current block is predicted using matrix-based intra prediction, MIP, mode.

An eighth aspect of the method according to the seventh aspect, wherein the secondary conversion core is one of the secondary conversion cores that are used for the non-MIP mode.

A ninth aspect of the method according to the seventh aspect, wherein the secondary conversion core is different from any of the secondary conversion cores that are used for non-MIP mode.

A tenth aspect of the encoder (20) comprising a processing circuit for performing a method according to any of the first to ninth aspects.

An eleventh aspect of the decoder (30) comprising processing circuitry for performing a method according to any of the first to ninth aspects.

A twelfth aspect of a computer program product comprising program code for performing a method according to any of the first through ninth aspects.

A thirteenth decoder aspect comprising: one or more processors; and a non-transitory computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the program, when executed by the processors, configures a decoder to perform the method according to any of the first to ninth aspects.

A thirteenth encoder aspect comprising: one or more processors; and a non-transitory computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the program, when executed by the processors, configures an encoder to perform a method according to any of the first to ninth aspects.

Claims (127)

1. An encoding method implemented by a decoding device or an encoding device, containing: determining the intra prediction mode of the current block; And determining the secondary transform selection of the current block based on the intra prediction mode defined for the current block: when the intra prediction mode is less than 0, the set of inseparable secondary transform kernels is set to 1; when the intra prediction mode is 0 or 1, the set of inseparable secondary transform kernels is set to 0; when the intra prediction mode is greater than or equal to 2 and less than or equal to 12, the set of inseparable secondary transform kernels is set to 1; when the intra prediction mode is greater than or equal to 13 and less than or equal to 23, the set of inseparable secondary transform kernels is set to 2; when the intra prediction mode is greater than or equal to 24 and less than or equal to 44, the set of inseparable secondary transform kernels is set to 3; when the intra prediction mode is greater than or equal to 45 and less than or equal to 55, the set of inseparable secondary transform kernels is set to 2; When the intra prediction mode is greater than or equal to 56, the set of inseparable secondary transform kernels is set to 1. 2. The method of claim 1, wherein determining the selection of a secondary transform kernel for secondary transforming the current block is based on an intra prediction mode index of the current block. 3. The method of claim 2, wherein if the current block is not predicted using the MIP mode, matrix-based intra prediction, a secondary transform kernel is selected to secondary transform the current block. 4. The method according to claim 2 or 3, additionally containing: disable secondary conversion of the current block when the current block is predicted using MIP mode. 5. The method according to claim 4, in which disabling the secondary transformation of the current block contains: setting the value of the secondary conversion indication information for the current block to a default value. 6. Method according to any one of paragraphs. 3-5, in which whether the current block is predicted using the MIP mode or not is indicated according to the value of the MIP indication information. 7. Method according to any one of paragraphs. 3-6, in which in case the current block is not predicted using the MIP mode, the secondary transform is selected according to the following table wherein: sps_lfnst_enabled_flag equal to 1 indicates that lfnst_idx can be present in the inner encoding unit syntax; where sps_lfnst_enabled_fag equal to 0 indicates that lfnst_idx is not present in the internal encoding unit syntax; intra_mip_flag [ x0 ][ y0 ] equal to 1 indicates that the intra prediction type for luma samples is matrix-based intra prediction, intra_mip_flag[ x0 ][ y0 ] equal to 0 indicates that the intra prediction type for luma samples is not intra matrix-based prediction; however, when intra_mip_flag[ x0 ][ y0 ] is missing, it is assumed to be 0; lfnst_idx indicates whether and which of the two low frequency non-separable transform kernels is used in the selected transform set; lfnst_idx equal to 0 indicates that the low frequency non-separable transform is not used in the current encoding unit; however, when lfnst_idx is absent, it is assumed to be 0; transform_skip_flag [ x0 ][ y0 ][ cIdx ] indicates whether the transform is applied to the corresponding transform block or not. 8. Method according to claim 1 or 2, containing: providing four sets of transformation kernels having transformation kernel set index 0, 1, 2, 3, respectively, wherein each set of transformation kernels of the four sets of transformation kernels contains two transformations; selecting a reduced secondary transform matrix, RST, by determining a set of transform kernels from four sets of transform kernels to be applied to the current block in accordance with the intra prediction mode of the current block, as follows: if the current internal block is predicted using a cross-component linear model mode, CCLM, or using a MIP mode, selecting a set of transformation kernels having a set of transformation kernels index 0; otherwise, select a set of transformation kernels using the current block's intra prediction mode index value and the following table: IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1 9. The method according to claim 1 or 2, comprising: providing four sets of transformation kernels having index 0, 1, 2, 3 of the set of transformation kernels, respectively, wherein each set of transformation kernels of the four sets of transformation kernels contains two transformations; providing a fifth set of transformation kernels having transformation kernel set index 4, wherein the fifth set of transformation kernels has the same dimensions as the sets of transformation kernels having index 0-3 of the set of transformation kernels; wherein the fifth set of transformation kernels is retrained based on the same machine learning method and the input training set for the MIP mode; selecting a reduced secondary transform matrix, RST, by determining a set of transform kernels from five sets of transform kernels to be applied to the current block according to the intra prediction mode of the current block, as follows: if the current inner block is predicted using the cross-component linear model mode, CCLM, selecting a set of transformation kernels having index 0 of the set of transformation kernels; if the current internal block is predicted using the MIP mode, selecting a set of transformation kernels having a set of transformation kernels index 4; otherwise, select a set of transformation kernels using the current block's intra prediction mode index value and the following table: IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1 10. An encoder (20) containing a processing circuit for performing the method according to any one of claims. 1-9 when implemented by an encoder. 11. A decoder (30) comprising a processing circuit for performing the method according to any one of claims. 1-9 when implemented by a decoding device. 12. Decoder (30), containing: one or more processors; And a non-transitory computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the program, when executed by the processors, configures a decoder to perform the method of any one of claims. 1-9 when implemented by a decoding device. 13. Encoder (20), containing: one or more processors; And a non-transitory computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the program, when executed by the processors, configures an encoder to perform the method of any one of claims. 1-9 when implemented by an encoding device. 14. Decoder (30), containing: a determination unit configured to determine the intra prediction mode of the current block; And a selector configured to determine a secondary transform selection of the current block based on an intra prediction mode defined for the current block: when the intra prediction mode is less than 0, the set of inseparable secondary transform kernels is set to 1; when the intra prediction mode is 0 or 1, the set of inseparable secondary transform kernels is set to 0; when the intra prediction mode is greater than or equal to 2 and less than or equal to 12, the set of inseparable secondary transform kernels is set to 1; when the intra prediction mode is greater than or equal to 13 and less than or equal to 23, the set of inseparable secondary transform kernels is set to 2; when the intra prediction mode is greater than or equal to 24 and less than or equal to 44, the set of inseparable secondary transform kernels is set to 3; when the intra prediction mode is greater than or equal to 45 and less than or equal to 55, the set of inseparable secondary transform kernels is set to 2; When the intra prediction mode is greater than or equal to 56, the set of inseparable secondary transform kernels is set to 1. 15. The decoder (30) of claim 14, wherein determining the selection of a secondary transform kernel for secondary transforming the current block is based on an intra prediction mode index of the current block. 16. The decoder (30) according to claim 15, wherein in case the current block is not predicted using the MIP mode, matrix-based intra prediction, a secondary transform kernel is selected to secondary transform the current block. 17. Decoder (30) according to claim 15 or 16, wherein the decoder (30) additionally contains: disable secondary conversion of the current block when the current block is predicted using MIP mode. 18. The decoder (30) according to claim 17, in which disabling the secondary conversion of the current block contains: setting the value of the secondary conversion indication information for the current block to a default value. 19. Decoder (30) according to any one of claims. 16-18, in which whether the current block is predicted using the MIP mode or not is indicated according to the value of the MIP indication information. 20. Decoder (30) according to any one of claims. 16-19, in which in case the current block is not predicted using MIP mode, the secondary transform is selected according to the following table lfnstNotTsFlag = ( treeType = = DUAL_TREE_CHROMA | |
transform_skip_flag[ x0 ][ y0 ][ 0 ] = = 0 ) &&
( treeType == DUAL_TREE_LUMA | |
( transform_skip_flag[ x0 ][ y0 ][ 1 ] = = 0 &&
transform_skip_flag[ x0 ][ y0 ][ 2 ] = = 0 ) ) if( Min( lfnstWidth, lfnstHeight ) >= 4 && sps_lfnst_enabled_flag = = 1 &&
CuPredMode[ chType ][ x0 ][ y0 ] = = MODE_INTRA && lfnstNotTsFlag = = 1 &&
( treeType = = DUAL_TREE_CHROMA | | !intra_mip_flag[ x0 ][ y0 ] | |
Min( lfnstWidth, lfnstHeight ) >= 16 ) &&
Max( cbWidth, cbHeight ) <= MaxTbSizeY) { if( ( IntraSubPartitionsSplitType != ISP_NO_SPLIT | | LfnstDcOnly = = 0 ) &&
LfnstZeroOutSigCoeffFlag = = 1 ) lfnst_idx ae(v) } wherein: sps_lfnst_enabled_flag equal to 1 indicates that lfnst_idx can be present in the inner encoding unit syntax; where sps_lfnst_enabled_fag equal to 0 indicates that lfnst_idx is not present in the internal encoding unit syntax; intra_mip_flag [ x0 ][ y0 ] equal to 1 indicates that the intra prediction type for luma samples is matrix-based intra prediction, intra_mip_flag[ x0 ][ y0 ] equal to 0 indicates that the intra prediction type for luma samples is not intra matrix-based prediction; however, when intra_mip_flag[ x0 ][ y0 ] is missing, it is assumed to be 0; lfnst_idx indicates whether and which of the two low frequency non-separable transform kernels is used in the selected transform set; lfnst_idx equal to 0 indicates that the low frequency non-separable transform is not used in the current encoding unit; however, when lfnst_idx is absent, it is assumed to be 0; transform_skip_flag [ x0 ][ y0 ][ cIdx ] indicates whether the transform is applied to the corresponding transform block or not. 21. Decoder (30) according to claim 14 or 15, containing: providing four sets of transformation kernels having transformation kernel set index 0, 1, 2, 3, respectively, wherein each set of transformation kernels of the four sets of transformation kernels contains two transformations; selecting a reduced secondary transform matrix, RST, by determining a set of transform kernels from four sets of transform kernels to be applied to the current block in accordance with the intra prediction mode of the current block, as follows: if the current internal block is predicted using a cross-component linear model mode, CCLM, or using a MIP mode, selecting a set of transformation kernels having a set of transformation kernels index 0; otherwise, select a set of transformation kernels using the current block's intra prediction mode index value and the following table: IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1 22. Decoder (30) according to claim 14 or 15, containing: providing four sets of transformation kernels having transformation kernel set index 0, 1, 2, 3, respectively, wherein each set of transformation kernels of the four sets of transformation kernels contains two transformations; providing a fifth set of transformation kernels having transformation kernel set index 4, wherein the fifth set of transformation kernels has the same dimensions as the sets of transformation kernels having index 0-3 of the set of transformation kernels; wherein the fifth set of transformation kernels is retrained based on the same machine learning method and the input training set for the MIP mode; selecting a reduced secondary transform matrix, RST, by determining a set of transform kernels from five sets of transform kernels to be applied to the current block according to the intra prediction mode of the current block, as follows: if the current inner block is predicted using the cross-component linear model mode, CCLM, selecting a set of transformation kernels having index 0 of the set of transformation kernels; if the current internal block is predicted using the MIP mode, selecting a set of transformation kernels having a set of transformation kernels index 4; otherwise, select a set of transformation kernels using the current block's intra prediction mode index value and the following table: IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1 23. Encoder (20), containing: a determination unit configured to determine the intra prediction mode of the current block; And a selector configured to determine a secondary transform selection of the current block based on an intra prediction mode defined for the current block: when the intra prediction mode is less than 0, the set of inseparable secondary transform kernels is set to 1; when the intra prediction mode is 0 or 1, the set of inseparable secondary transform kernels is set to 0; when the intra prediction mode is greater than or equal to 2 and less than or equal to 12, the set of inseparable secondary transform kernels is set to 1; when the intra prediction mode is greater than or equal to 13 and less than or equal to 23, the set of inseparable secondary transform kernels is set to 2; when the intra prediction mode is greater than or equal to 24 and less than or equal to 44, the set of inseparable secondary transform kernels is set to 3; when the intra prediction mode is greater than or equal to 45 and less than or equal to 55, the set of inseparable secondary transform kernels is set to 2; When the intra prediction mode is greater than or equal to 56, the set of inseparable secondary transform kernels is set to 1. 24. The encoder (20) of claim 23, wherein determining the selection of a secondary transform kernel for secondary transforming the current block is based on an intra prediction mode index of the current block. 25. The encoder (20) of claim 24, wherein in case the current block is not predicted using the MIP mode, matrix-based intra prediction, a secondary transform kernel is selected to secondary transform the current block. 26. Encoder (20) according to claim 24 or 25, wherein encoder (20) additionally contains: disable secondary conversion of the current block when the current block is predicted using MIP mode. 27. The encoder (20) according to claim 26, in which disabling the secondary conversion of the current block contains: setting the value of the secondary conversion indication information for the current block to a default value. 28. Encoder (20) according to any one of claims. 26, 27, in which whether the current block is predicted using the MIP mode or not is indicated according to the value of the MIP indication information. 29. Encoder (20) according to any one of claims. 25-28, in which in case the current block is not predicted using the MIP mode, the secondary transform is selected according to the following table lfnstNotTsFlag = ( treeType = = DUAL_TREE_CHROMA | |
transform_skip_flag[ x0 ][ y0 ][ 0 ] = = 0 ) &&
( treeType == DUAL_TREE_LUMA | |
( transform_skip_flag[ x0 ][ y0 ][ 1 ] = = 0 &&
transform_skip_flag[ x0 ][ y0 ][ 2 ] = = 0 ) ) if( Min( lfnstWidth, lfnstHeight ) >= 4 && sps_lfnst_enabled_flag = = 1 &&
CuPredMode[ chType ][ x0 ][ y0 ] = = MODE_INTRA && lfnstNotTsFlag = = 1 &&
( treeType = = DUAL_TREE_CHROMA | | !intra_mip_flag[ x0 ][ y0 ] | |
Min( lfnstWidth, lfnstHeight ) >= 16 ) &&
Max( cbWidth, cbHeight ) <= MaxTbSizeY) { if( ( IntraSubPartitionsSplitType != ISP_NO_SPLIT | | LfnstDcOnly = = 0 ) &&
LfnstZeroOutSigCoeffFlag = = 1 ) lfnst_idx ae(v) } wherein: sps_lfnst_enabled_flag equal to 1 indicates that lfnst_idx can be present in the inner encoding unit syntax; where sps_lfnst_enabled_fag equal to 0 indicates that lfnst_idx is not present in the internal encoding unit syntax; intra_mip_flag [ x0 ][ y0 ] equal to 1 indicates that the intra prediction type for luma samples is matrix-based intra prediction, intra_mip_flag[ x0 ][ y0 ] equal to 0 indicates that the intra prediction type for luma samples is not intra matrix-based prediction; however, when intra_mip_flag[ x0 ][ y0 ] is missing, it is assumed to be 0; lfnst_idx indicates whether and which of the two low frequency non-separable transform kernels is used in the selected transform set; lfnst_idx equal to 0 indicates that the low frequency non-separable transform is not used in the current encoding unit; however, when lfnst_idx is absent, it is assumed to be 0; transform_skip_flag [ x0 ][ y0 ][ cIdx ] indicates whether the transform is applied to the corresponding transform block or not. 30. Encoder (20) according to claim 23 or 24, containing: providing four sets of transformation kernels having transformation kernel set index 0, 1, 2, 3, respectively, wherein each set of transformation kernels of the four sets of transformation kernels contains two transformations; selecting a reduced secondary transform matrix, RST, by determining a set of transform kernels from four sets of transform kernels to be applied to the current block in accordance with the intra prediction mode of the current block, as follows: if the current internal block is predicted using a cross-component linear model mode, CCLM, or using a MIP mode, selecting a set of transformation kernels having a set of transformation kernels index 0; otherwise, select a set of transformation kernels using the current block's intra prediction mode index value and the following table: IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1 31. Encoder (20) according to claim 23 or 24, containing: providing four sets of transformation kernels having transformation kernel set index 0, 1, 2, 3, respectively, wherein each set of transformation kernels of the four sets of transformation kernels contains two transformations; providing a fifth set of transformation kernels having transformation kernel set index 4, wherein the fifth set of transformation kernels has the same dimensions as the sets of transformation kernels having index 0-3 of the set of transformation kernels; wherein the fifth set of transformation kernels is retrained based on the same machine learning method and the input training set for the MIP mode; selecting a reduced secondary transform matrix, RST, by determining a set of transform kernels from five sets of transform kernels to be applied to the current block according to the intra prediction mode of the current block, as follows: if the current inner block is predicted using the cross-component linear model mode, CCLM, selecting a set of transformation kernels having index 0 of the set of transformation kernels; if the current internal block is predicted using the MIP mode, selecting a set of transformation kernels having a set of transformation kernels index 4; otherwise, select a set of transformation kernels using the current block's intra prediction mode index value and the following table: IntraPredMode transform set index IntraPredMode <0 1 0 <= IntraPredMode <= 1 0 2 <= IntraPredMode <= 12 1 13 <= IntraPredMode <= 23 2 24 <= IntraPredMode <= 44 3 45 <= IntraPredMode <= 55 2 56 <= IntraPredMode 1