RU2811983C2 - Encoder, decoder and related methods for sub-block partition mode - Google Patents

Abstract

FIELD: image encoding and decoding.

SUBSTANCE: get the pointer value for the current block according to the bitstream. Get the value of the first parameter for the current block and the value of the second parameter for the current block according to the value of the pointer and the predefined lookup table, obtaining the value of the sampling distance for the sample that is in the current block according to the value of the first parameter and the value of the second parameter. The prediction value for the sample is obtained according to the sampling distance value for the sample, where the indicator is merge_gpm_partition_idx, where the first parameter is angleIdx, which represents the angle to split the current block, where the second parameter is distanceIdx, which represents the distance to split the current block.

EFFECT: improved compression ratio with minimal loss of image quality or no such loss at all.

14 cl, 18 dwg, 4 tbl

Description

TECHNICAL FIELD

Embodiments of the present application (disclosure) generally relate to the field of image processing and, more specifically, to prediction using sub-block modes.

BACKGROUND 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, and real-time conversational applications such as video chat, video conferencing, DVD and Blu-ray discs. , systems for collecting and editing video content and 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 a video decompression device at the recipient, which decodes the video data. With limited network resources and ever-increasing demands for higher video quality, improved compression and decompression techniques that improve compression rates with little or no loss in image quality are desired.

SUMMARY OF THE INVENTION

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

The above and other objectives are achieved by solving the independent claims. Additional forms of implementation are obvious from the dependent claims, description and figures.

The first aspect of the present invention provides a method for performing encoding implemented by a decoding apparatus, the method comprising: obtaining a bit stream; obtaining a pointer value for the current block according to the bit stream; obtaining the value of the first parameter for the current block and the value of the second parameter for the current block according to the pointer value and the predefined lookup table; obtaining a sample distance value for a sample that is in the current block according to the value of the first parameter and the value of the second parameter; and obtaining a prediction value for the sample according to the sampling distance value for the sample.

According to embodiments of the present invention, parameters for block division (for example, an angle parameter, a distance parameter... and the like) are stored in a predefined lookup table, therefore, the actual values of these parameters do not need to be transmitted in the bit stream, and the values of these parameters are obtained according to the indication value, encoded in the bitstream. In this way, encoding efficiency can be improved.

As shown in FIG. 15, a method for performing encoding implemented by a decoding apparatus is disclosed, the method comprising:

S1501: receive bit stream.

The bit stream can be obtained according to a wireless network or a wired network. The bit stream can be 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, microwave, WIFI, Bluetooth, LTE or 5G.

In an embodiment, a bit stream is a sequence of bits, for example in the form of a network abstraction layer (NAL) unit stream or a byte stream that forms a representation of a sequence of access units (AUs) forming one or more coded video sequences (CVS).

In some embodiments, for the decoding process, the decoder side reads the bitstream and outputs decoded images from the bitstream; For the encoding process, the encoder side creates a bit stream.

Typically the bitstream will contain syntax elements that are formed by the syntax structure. syntax element: A data element represented in a bitstream.

syntax structure: zero or more syntax elements present together in a bitstream in a specified order.

In a specific example, bitstream formats specify the relationship between a stream of Network Abstraction Layer (NAL) units and a byte stream, each of which is called a bitstream.

The bit stream may be, for example, in one of two formats: a NAL unit stream format or a byte stream format. The NAL unit stream format is conceptually a more "basic" type. The NAL unit stream format contains a sequence of syntactic structures called NAL units. This sequence is ordered in decoding order. There are restrictions placed on the decoding order (and content) of NAL units in a NAL unit stream.

A byte stream format can be constructed from a NAL unit stream format by arranging the NAL units in decoding order and appending to each NAL unit an initial code prefix and zero or more null-valued bytes to form a byte stream. The NAL unit stream format can be extracted from the byte stream format by searching for the location of a unique starting code prefix pattern within that byte stream.

This section describes an embodiment of the relationship between the original and decoded images, which is carried through a bitstream.

The video source, which is represented by a bitstream, is a sequence of images in decoding order.

Each of the original and decoded images consists of one or more sample arrays:

- Brightness (Y) only (monochrome).

- Brightness and two chromaticities (YCbCr or YCgCo).

- Green, Blue and Red (GBR, also known as RGB).

- Arrays representing other unspecified monochrome or tristimulus color samples (eg, YZX, also known as XYZ).

The variables and terms associated with these arrays are referred to as luma (either L or Y) and chroma, with the two chroma arrays referred to as Cb and Cr; regardless of the actual color representation method used. The actual color representation method used may be specified in the syntax that is specified in the VUI parameters as specified in ITU-T H.SEI | ISO/IEC 23002-7.

The SubWidthC and SubHeightC variables are specified in Table 2 depending on the chroma format sampling structure, which is specified through sps_chroma_format_idc and sps_separate_colour_plane_flag.

Table 2 - SubWidthC and SubHeightC values derived from sps_chroma_format_idc and sps_separate_colour_plane_flag

sps_chroma_format_idc sps_separate_colour_plane_flag Chroma format SubWidthC SubHeightC 0 0 Monochrome 1 1 1 0 4:2:0 2 2 2 0 4:2:2 2 1 3 0 4:4:4 1 1 3 1 4:4:4 1 1

In a monochrome sample there is only one sample array, which is nominally considered the luma array.

In a 4:2:0 sample, each of the two chroma arrays is half the height and half the width of the luma array.

In a 4:2:2 sample, each of the two chroma arrays has the same height and half the width of the lumina array.

In a 4:4:4 sample, depending on the value of sps_separate_colour_plane_flag, the following applies:

- If sps_separate_colour_plane_flag is 0, each of the two chroma arrays has the same height and width as the luminance array.

- Otherwise (sps_separate_colour_plane_flag is equal to 1) the three color planes are treated separately as monochrome sampled images.

S1502: Get the pointer value for the current block according to the bit stream.

In an embodiment, the pointer value is used to specify the shape of the split in geometric split merge mode. For example, the pointer could be merge_gpm_partition_idx[ x0 ][ y0 ], where merge_gpm_partition_idx[ x0 ][ y0 ] specifies the partition form of the geometric partition merge mode. The array indices x0, y0 specify the location (x0, y0) of the top left luminance sample of the encoding block in question relative to the top left luminance sample of the image.

Typically the merge_gpm_partition_idx[ x0 ][ y0 ] value is decoded from the bitstream. In the example, the range of values for merge_gpm_partition_idx[ ][ ] is from 0 to 63, including 0 and 63. In the example, the decoding process for merge_gpm_partition_idx[ ][ ] is "bypass".

When merge_gpm_partition_idx[ x0 ][ y0 ] is not present, it is assumed to be 0.

S1503: Obtain the value of the first parameter for the current block and the value of the second parameter for the current block according to the pointer value and the predefined lookup table.

In one implementation, the first parameter represents the angle (or is the angle) for dividing the current block.

In one implementation, the second parameter represents the distance to split the current block.

In one implementation, the predefined lookup table contains pairs of first and second parameters,

provided that when the first parameter in a pair represents an angle corresponding to one of 0, 45, 90, 135, 180, 225, 270 or 315 degrees, the corresponding second parameter in that pair does not represent a distance of zero samples from the center of the current block.

In one implementation, the predefined lookup table contains pairs of first and second parameters,

wherein the first parameter in the pair represents an angle other than one of 0, 45, 90, 135, 180, 225, 270, or 315 degrees, and the corresponding second parameter in the pair represents a distance of zero samples from the center of the current block.

In one implementation, the predefined lookup table contains pairs of first and second parameters,

wherein the first parameter in the pair represents an angle corresponding to one of 0, 45, 90, 135, 180, 225, 270, or 315 degrees, and the corresponding second parameter in the pair represents a distance of zero samples from the center of the current block.

In one implementation, the second parameter specifies the distance index of the geometric section, or the second parameter describes the distance from the demarcation line to the center of the current block.

In an embodiment, the partition angle variable angleIdx (parameter 1) and the distance variable distanceIdx (parameter 2) of the geometric partition mode are set according to the value of merge_gpm_partition_idx[ xCb ][ yCb ] (pointer) as specified in the following table. It can be understood that in the mentioned implementation, this relationship may be implemented according to Table 1 or according to some function.

Table 1: Specification of angleIdx and distanceIdx based on merge_gpm_partition_idx

merge_gpm_partition_idx 0 1 2 3 4 5 6 7 8 9 10 eleven 12 13 14 15 angleIdx 0 0 2 2 2 2 3 3 3 3 4 4 4 4 5 5 distanceIdx 1 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 merge_gpm_partition_idx 16 17 18 19 20 21 22 23 24 25 26 27 28 29 thirty 31 angleIdx 5 5 8 8 eleven eleven eleven eleven 12 12 12 12 13 13 13 13 distanceIdx 2 3 1 3 0 1 2 3 0 1 2 3 0 1 2 3 merge_gpm_partition_idx 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 angleIdx 14 14 14 14 16 16 18 18 18 19 19 19 20 20 20 21 distanceIdx 0 1 2 3 1 3 1 2 3 1 2 3 1 2 3 1 merge_gpm_partition_idx 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 angleIdx 21 21 24 24 27 27 27 28 28 28 29 29 29 thirty thirty thirty distanceIdx 2 3 1 3 1 2 3 1 2 3 1 2 3 1 2 3

S1504: Obtaining the sampling distance value for the sample that is in the current block according to the value of the first parameter and the value of the second parameter.

In an embodiment, this step comprises:

Step 3.1: Get the index value of the angle parameter (alphaN or angleIdx) for the current block, the width (W) value of the current block, the height (H) value of the current block. W and H represent the width and height of the current block by the number of samples. For example, a coding block whose width and height are 8 is a square block containing 64 samples. In another example, W and H represent the width and height of the current block by the number of brightness samples. The index value of the angle parameter can be obtained according to the above description referring to Table 1.

Step 3.2: Obtaining the whRatio value according to the W value and the H value, the whRatio value represents the ratio between the width and height of the current encoding block.

In the example whRatio=H/W; or whRatio=W/H.

In another example, two variables nCbW and nCbH specify the width and height of the current encoding block, and the variable cIdx specifies the color component index.

The variables nW, nH and whRatio are output as follows:

nW=( cIdx== 0 ) ? nCbW : nCbW * SubWidthC;

nH=( cIdx== 0 ) ? nCbH : nCbH * SubHeightC;

whRatio=nH/nW.

In the example, the variables SubWidthC and SubHeightC are specified in Table 2.

Step 3.3: Retrieving the shiftHor value according to the lookup table, alpha value and whRatio value, in the example the alpha value (alphaN or angleIdx) and whRatio value are used as index values of the lookup table. The shiftHor value can also be obtained according to a function, wherein the alpha value (alphaN or angleIdx) and the whRatio value represent the input of the function, and the shiftHor value represents the output of the function. In the example, the function result is the same as or the same as the lookup table. In the example, the value shiftHor represents the quantization step size for the sampling distance calculation process.

In another example, the function could be represented as shiftHor=( angleIdx % 16== 8 | | ( angleIdx % 16 != 0 && whRatio > 0 ) ) ? 0 : 1.

Step 3.4: The value of sample_dist is calculated according to the value of shiftHor.

In the example, to calculate the sample distance (sample_dist), the offsetX and offsetY variables are first output as follows:

If shiftHor is 0, the following applies:

offsetX=( −nW ) >> 1,

offsetY=( ( −nH ) >> 1 ) + ( angleIdx < 16 ? ( distanceIdx * nH ) >> 3 : −( ( distanceIdx * nH ) >> 3 ) );

Otherwise (shiftHor is 1), the following applies:

offsetX=( ( −nW ) >> 1 ) + ( angleIdx < 16 ? ( distanceIdx * nW ) >> 3 : −( ( distanceIdx * nW ) >> 3 ) );

offsetY=( − nH ) >> 1;

- Variables xL and yL are output as follows:

xL=( cIdx== 0 ) ? x : x * SubWidthC

yL=( cIdx== 0 ) ? y : y * SubHeightC

sample_dist=( ( ( xL+offsetX ) << 1 ) + 1 ) * disLut[ displacementX ] + ( ( ( yL + offsetY )  << 1 ) + 1 ) ) * disLut[ displacementY ].

The displacementX and displacementY variables are output as follows:

hwRatio=cbHeight/cbWidth;

displacementX=angleIdx;

displacementY=( angleIdx+8 ) % 32.

The disLut array is specified in Table 3 below.

In some embodiments, according to the geometric model, samples in a coding block are considered to be in two subblocks. Subblock A or subblock B may contain some (but not all) of the samples in the current encoding block. Subblock A or subblock B can be represented according to the sample_dist sign of each of the samples. Sample_dist can be obtained according to the examples and embodiments in other paragraphs.

S1505: Obtain the prediction value for the sample according to the sampling distance value for the sample.

In one implementation, obtaining the prediction value for a sample according to the sampling distance value for a sample comprises:

calculating two weight coefficients according to the sampling distance value; And

obtaining a prediction value for the sample according to the first prediction value, the second prediction value, and the two weights.

In one implementation, the sample distance value is a horizontal distance or a vertical distance, or a combination of vertical and horizontal distances, from said sample to a demarcation line, wherein the demarcation line is used to split a coding block into two sub-blocks.

In one example, the calculated sample_dist is used to calculate weights, wherein the weights are used to combine a first prediction value and a second prediction value corresponding to said sample. In the example, the weights are denoted as sampleWeight1 and sampleWeight2, meaning a weight corresponding to the first prediction value and a weight corresponding to the second prediction value.

In one example, the weights are calculated according to the following functions

weightIdxL=partFlip ? 32+sample_dist : 32 − sample_dist;

wValue=Clip3( 0, 8, ( weightIdxL+4 ) >> 3 ).

In this example, wValue represents sampleWeight1 and 8-wValue represents sampleWeight2. The partFlip variable is defined according to the angleIdx value. In the example, partFlip=( angleIdx >= 13 && angleIdx <= 27 ) ? 0 : 1, or partFlip=( angleIdx >= 13 && angleIdx <= 27 ) ? 10.

In one example, the combined prediction sample value at the sample coordinate (x,y) is calculated according to the first prediction value at the (x,y) coordinate, the second prediction value at the (x,y) coordinate, sampleWeight1, and sampleWeight2.

In the example, the prediction sample value is output as follows:

pbSamples[ x ][ y ]=Clip3( 0, ( 1 << BitDepth ) − 1, ( predSamplesLA[ x ][ y ] * wValue + predSamplesLB[ x ][ y ] * ( 8 − wValue ) + offset1 ) >>> shift1).

In this case, bitDepth represents the bit depth of the sample, the shift1 variable is obtained according to the mentioned bitDepth, in the example shift1= Max( 5, 17 - BitDepth ); The variable offset1 is obtained according to shift1, in the example offset1= 1 << ( shift1-1 ), predSamplesLA and predSamplesLB are two (nCbW)x(nCbH) arrays.

In one embodiment, a method for performing encoding implemented by an encoding device is disclosed, comprising: selecting a first parameter value and a second parameter value;

obtaining an index value according to the value of the first parameter, the value of the second parameter and the lookup table; and encoding the index value into the bit stream.

The details for each stage on the encoder side correspond to the examples above on the decoder side.

As shown in FIG. 16, a second aspect of the present invention provides a decoding apparatus 1600, the decoding apparatus comprising:

a receiving unit 1601, which is configured to receive a bit stream and obtain a pointer value for a current block according to the bit stream;

a division parameter processing unit 1602, which is configured to obtain a first parameter value for the current block and a second parameter value for the current block according to the pointer value and the predefined lookup table;

a calculation unit 1603, which is configured to obtain a sample distance value for a sample that is in the current block according to the value of the first parameter and the value of the second parameter; And

a prediction module 1604, which is configured to obtain a prediction value for a sample according to a sampling distance value for the sample.

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

In an embodiment, a decoder (30) or encoder (20) is disclosed comprising processing circuitry for performing a method according to any of the above embodiments and implementations.

In an embodiment, a computer program product is disclosed comprising program code for executing a method according to any of the above embodiments and implementations.

In an embodiment, a decoder or encoder is disclosed, comprising:

one or more processors; And

a non-transitory computer-readable medium coupled to the processors and storing a program portion for execution by the processors, wherein the program portion, when executed by the processors, configures a decoder or encoder to perform a method according to any of the above embodiments and implementations.

In an embodiment, a non-transitory storage medium is disclosed that includes an encoded bit stream decoded by an image decoding apparatus, wherein the bit stream is generated by dividing a frame of a video signal or an image signal into a plurality of blocks and includes a plurality of syntax elements, wherein the plurality of syntax elements comprises: pointer (syntax) according to any of the above embodiments and implementations.

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 THE DRAWINGS

Below, embodiments of the invention 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 exemplary 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. 6a illustrates an example of a co-located block;

FIG. 6b illustrates an example of spatial neighboring blocks.

FIG. 7 illustrates some examples of the triangular prediction mode.

FIG. 8 illustrates some examples of the sub-block prediction mode.

FIG. 9-12 show some examples of block splitting.

FIG. 13 is a block diagram showing an exemplary structure of a content delivery system 3100 that implements a content delivery service.

FIG. 14 is a block diagram showing the structure of an exemplary terminal device.

FIG. 15 is a flowchart showing an embodiment of a method related to the present invention.

FIG. 16 is a block diagram showing an embodiment of an apparatus related to the present invention.

Identical reference numerals hereinafter refer to identical or at least functionally equivalent features unless expressly indicated otherwise.

DETAILED DESCRIPTION OF IMPLEMENTATION OPTIONS

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. 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 sequence. Instead of the term "image", the terms "frame" or "picture" may be used interchangeably in the field of video coding. Video encoding (or the implementation of 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 end and typically involves reverse processing from the encoder to reconstruct 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 an encoding part and a decoding part is also called CODEC (encoding 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 sample-domain prediction and 2D transform coding to apply quantization to 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-image) prediction and/or temporal (inter-image) prediction to generate a prediction block, the prediction block 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 transformation domain to reduce the amount of data (compression) to be transmitted, whereas in the decoder the reverse processing is compared to applied by the encoder to an encoded or compressed block to reconstruct the current block for presentation. In addition, the encoder duplicates the decoder's processing loop so that they will both generate identical predictions (eg, intra- and inter-predictions) and/or reconstructions for processing, ie encoding, of subsequent blocks.

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

FIG. 1A is a schematic block diagram illustrating an exemplary encoding system 10, such as video encoding system 10 (or encoding system 10 for short), which may use the techniques 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 include an image source 16, a preprocessor (or preprocessing 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 image generating 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 source of the images can be any type of memory or storage where any of the above images are stored.

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 should be understood that the pre-processing module 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 unit 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 (precise) separation of functionality of various blocks or functionality in source device 12 and/or destination device 14, as shown in FIG. 1A may vary depending on the 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 of FIG. 2 and/or any other encoder system or subsystem described in this document. Decoder 30 may be implemented through processing circuit 46 to implement various modules, as discussed with respect to 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 techniques are partially implemented in software, the apparatus may store the 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 carry out the techniques 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 can be applied to video encoding settings (such as video encoding or video decoding) that do not necessarily involve transferring 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 ease 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 on Video Coding (JCT-VC) Expert Group. ITU-T Video Coding (VCEG) and ISO/IEC Moving Picture Expert Group (MPEG). One of ordinary skill 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 techniques 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 ( DPB) of decoded images, a mode selection unit 260, an entropy encoding unit 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 separating block 262. The inter-prediction block 244 may include a motion estimation block and a motion compensation block (not shown). 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 a decoder (see video decoder 30 in Fig. 3). The inverse quantization unit 210, the inverse transform processing unit 212, the restoration unit 214, the loop filter 220, the decoded image buffer (DPB) 230, the inter-prediction unit 244, and the intra-prediction unit 254 also relate 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).

A (digital) image 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 a color space or RBG format, an image contains a corresponding array of red, green, or blue samples. However, in video encoding, each pixel is typically represented in a color space or luminance and chrominance format, 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 (CTU) (H.265/HEVC and VVC). The image division block may be configured to use the same block size for all images in the 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 (M-column by N-row) array of samples 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.

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 (additional 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 unit 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 predefined 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 may be used and signaled from encoder to decoder, for example in a bitstream. Quantization is a lossy operation in which the loss increases with the size of the quantization steps.

Embodiments of video encoder 20 (respectively quantization unit 208) may be configured to output quantization parameters (QPs), such as directly or encoded through entropy encoding unit 270, so that, for example, video decoder 30 can receive and apply 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 (ALF), anti-aliasing filters, boost filters, etc. sharpening or joint filters, or any combination of them. Although loop filter block 220 is shown in FIG. 2 as an in 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 selecting unit 260 includes a separating unit 262, an inter-prediction unit 244, and an intra-prediction unit 254, and is configured to receive or obtain original image data, for example, the original block 203 (the current block 203 of the current image 17), and reconstructed image data, for example 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 (for example, 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 selection block 260 may be configured to determine or select a split for the current block prediction mode (including non-split) and prediction mode (eg, intra- or inter-prediction mode) and generate a corresponding prediction block 265 that is used to calculate 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 minimum distortion at a certain rate. 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, partitioning unit 262 may be configured to partition block 203 into smaller block sections or sub-blocks (which form blocks again), for example iteratively using quad-tree partitioning (QT), binary 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 division (for example, through the division block 260) and prediction processing (through the inter-prediction block 244 and the intra-prediction block 254) performed by the exemplary video encoder 20 are explained in more detail.

Separation

Divider 262 may divide (or split) the current block 203 into smaller sections, such as smaller blocks of square or rectangular size. 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 earlier, 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, such as the newest video coding standard currently under development called Versatile Video Coding (VVC), a quadtree-binary tree (QTBT) partition is used to divide the encoding block. In a block structure, the 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, multiple partitioning, such as ternary tree partitioning, has been proposed to 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 separation techniques described herein.

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

Intra-prediction

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

The intra-prediction block 254 is configured to use reconstructed samples of neighboring blocks of the same current image to generate an intra-prediction block 265 according to an intra-prediction mode from a set of intra-prediction modes.

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

Inter-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 region search windows around the area of the current block, a reference image to search for 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 (the 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 into the motion estimation block. This displacement is also called motion vector (MV).

The motion compensation unit is configured to obtain, for example, receiving an inter-prediction parameter and performing 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 precision. 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 of the current image block, the motion compensation unit may locate the prediction block pointed to by the motion vector in one of the reference image lists.

The motion compensation block may also generate syntax elements associated with video blocks and slices for use by video decoder 30 when decoding video slice image blocks.

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 partitioning entropy entropy (PIPE) or other entropy coding method or methodology) or bypass (uncompressed) with respect to quantized coefficients 209, inter-prediction parameters, intra-prediction parameters, 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 to 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 block 206 for certain blocks or frames. 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 encoded video slice images and associated syntactic elements.

In the example in FIG. 3, decoder 30 includes an entropy decoding block 304, an inverse quantization block 310, an inverse transform processing block 312, a reconstruction block 314 (eg, adder 314), a loop filter 320, a decoded image buffer (DPB) 330, an inter-prediction block 344, and a 354 intra-predictions. The inter-prediction block 344 may be or include a motion compensation block. Video decoder 30 may, in some examples, perform a decoding pass generally reverse to the encoding pass 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 restoration 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 the generation of the “embedded decoder" of the video encoder 20. Accordingly, the inverse quantization unit 310 may be identical in function to the inverse quantization unit 110, the inverse transform processing unit 312 may be identical in function to the inverse transform processing unit 212, the restoration unit 314 may be identical in function to the contour restoration unit 214 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 of encoded image data 21 to obtain, for example, quantized coefficients 309 and/or decoded encoding parameters ( not shown in Fig. 3), for example, any or all of inter-prediction parameters (eg, reference image index and motion vector), intra-prediction parameter (eg, index or intra-prediction mode), transform parameters, quantization parameters, loop filter parameters and/or other syntax elements. Entropy decoding block 304 may be configured to apply decoding algorithms or schemes corresponding to encoding schemes as described with respect to entropy encoding block 270 of encoder 20. Entropy decoding block 304 may be further configured to provide inter-prediction parameters, an intra-prediction parameter and/or other syntax elements to mode selection block 360 and other parameters to other blocks of decoder 30. Video decoder 30 may receive syntax elements at the video slice level and/or video block level.

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 the video slice 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 213. 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, e.g., through an entropy decoding unit 304) to determine a transform to be applied to dequantized coefficients 311.

Recovery

The reconstruction block 314 (e.g., add block or adder 314) may be configured to add the reconstructed residual block 313 with the 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, boost filters, etc. sharpening or joint filters, or any combination of them. Although loop filter block 320 is shown in FIG. 3 as an in loop filter, in other configurations the loop filter block 320 may be implemented as a post loop filter.

Decoded Image Buffer

The decoded video image blocks 321 are then stored in a decoded image buffer 330, which stores the decoded images 331 as reference images for subsequent motion compensation for other images 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 by 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 partitioning or partitioning decisions and performs prediction on based on separation and/or prediction parameters or corresponding information received from the encoded image data 21 (eg, by parsing and/or decoding, eg, by entropy decoding unit 304). The mode selector 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 selection 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 selection block 360 is configured to create prediction blocks 365 for the video block of the current video slice based on the motion vectors and other syntactic elements received from the 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 mode selector 360 is configured to determine prediction information for a video block of the current video slice by parsing motion vectors 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 (eg, intra- or inter-prediction) used to encode video slice video blocks, the type of inter-prediction slice (eg, B-slice, P-slice, or GPB -slice), construction information for one or more reference picture lists for the 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 the video blocks in the current video slice.

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 filtering 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, planar, ATMVP mode subblock motion vectors, temporary motion vectors, and the like). For example, the value of a motion vector is limited to a predefined 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 set to 16, the range is -32768 ~ 32767; if bitDepth is set to 18, the range is -131072~131071. Here are two ways to limit the motion vector.

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

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

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

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

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

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 of -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 +2 ^bitDepth ) % 2 ^bitDepth (5)

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

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

mvy=( uy >= 2^bitDepth-1) ? (uy − 2^bitDepth ): 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(-2^bitDepth-1, 2^bitDepth-1 -1, vx)

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

where the definition of the Clip3 function is as follows:

Clip3( x, y, z )=

Operation "?" usually used as a shorthand to represent an "if...else" condition. For example, “X<K?X=1:X=0” can be interpreted as “if X is less than K, X is set to 1, otherwise (if X is not less than K) X is set to 0.”

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 units 420, transmitter units 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, the inclusion of 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 inputs (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.

In the example of constructing a list of merge candidates in accordance with ITU-T H.265, the list of merge candidates is built based on the following candidates:

1. up to four spatial candidates, which are derived from five spatial neighboring blocks,

2. one temporary candidate derived from two temporary, co-located blocks,

3. additional candidates, including combined bidirectional prediction candidates and

4. Candidates of zero motion vectors.

Spatial candidates

The motion information of spatial neighboring blocks is first added to a merging candidate list (in an example, the merging candidate list may be an empty list before adding the first motion vector to the merging candidate list) as motion information candidates. Here, adjacent blocks that are considered to be inserted into the merge list are illustrated in FIG. 6b. To merge inter-prediction blocks, up to four candidates are inserted into the merge list by sequentially testing A1, B1, B0, A0 and B2 in that order.

The motion information may include all motion data, including information about whether one or two reference picture lists are used, as well as a reference index and a motion vector for each reference picture list.

In one example, after checking whether an adjacent block is available and contains motion information, some additional redundancy checks are performed before accepting all motion data of the adjacent block as a motion information candidate. These redundancy checks can be divided into two categories for two different purposes:

Category 1, avoid having candidates with redundant motion data in the said list,

Category 2, prevent the merging of two sections that could be expressed by other means, creating redundant syntax.

Temporary candidates

Figure 6a illustrates the coordinates of blocks from which temporary motion information candidates are extracted. A co-located block is a block that has the same -x, -y coordinates as the current block, but is on a different image (one of the reference images). Temporary motion information candidates are added to the merge list if the list is not complete (in the example, the merge list is not complete when the number of candidates in the merge list is less than a threshold, for example, the threshold could be 4, 5, 6, etc.).

Generated candidates

After inserting spatial and temporal motion information candidates, if the merge list is still not complete, the generated candidates are added to fill the list. The list size is specified in the sequence parameter set and is fixed throughout the encoded video sequence.

Bidirectional Prediction

A special mode of inter-prediction is called "bi-directional (bi-)prediction", in which two motion vectors are used to predict a block. The motion vectors may point to the same or different reference pictures, and the reference picture may be indicated by a reference picture list ID and a reference picture index. For example, the first motion vector may point to the first image in the reference picture list L0, and the second motion vector may point to the first image in the reference picture list L1. Two reference picture lists (eg, L0 and L1) may be maintained, and the picture indicated by the first motion vector is selected from the L0 list, and the picture indicated by the second motion vector is selected from the L1 list.

In the example, if the motion information indicates bidirectional prediction, then the motion information includes two parts:

- L0 part: Motion vector and reference picture index that points to an entry in the L0 reference picture list.

- L1 Part: Motion vector and reference picture index, which points to an entry in the L1 reference picture list.

Picture Order Counter (POC): A variable that is associated with each picture uniquely identifies the associated picture among all pictures in the CVS (coded video sequence), and when the associated picture is to be output from the decoded picture buffer, indicates the position of the associated picture in the output order relative to the positions in order of output of other images in the same CVS that should be output from the decoded image buffer.

Each of the reference picture lists L0 and L1 may include one or more reference pictures, each of which is identified by a POC. The association with each reference index and POC value may be signaled in the bit stream. As an example, the reference picture lists L0 and L1 may include the following reference pictures:

List of reference images Reference index POC L0 0 12 L0 1 13 L1 0 13 L1 1 14

In the above example, the first entry (indicated by reference index 0) in the reference picture list L1 is a reference picture with a POC value of 13. The second entry (indicated by a reference index 1) in the reference picture list L1 is a reference picture with a POC value of 14.

The merge list construction process in ITU-T H.265 and VVC outputs a list of traffic information candidates. The VVC merge list construction process is described in section "8.3.2.2 Derivation process for luma motion vectors for merge mode" of JVET-L1001_v2 Universal Video Coding (Project 3), which is publicly available at http://phenix.it-sudparis.eu/jvet /. The term “motion information” refers to motion data that is needed to perform a motion-compensated prediction process. Motion information generally refers to the following information:

- Whether the block applies unidirectional or bidirectional prediction.

- ID of the reference picture that is used in prediction (2 IDs if the block uses bidirectional prediction).

- Motion vector (2 motion vectors if the block is subject to bidirectional prediction).

- Additional Information.

In VVC and H.265, the candidate list that is output when constructing the merge list includes N candidate traffic information. The number N is typically included in the bitstream and may be a positive integer, such as 5, 6, etc. The candidates that are included in the merge list that is constructed may include unidirectional prediction information or bidirectional prediction information. This means that the candidate that is selected from the merge list can specify a bidirectional prediction operation.

Triangle Prediction Mode

The concept of triangular prediction mode is to introduce a new triangular section for motion compensated prediction. As shown in FIG. 7, two triangular prediction units are used for CU, in the diagonal or reverse diagonal direction. Each triangular prediction unit for a CU is inter-predicted using a unidirectional motion vector and a reference frame index, which are derived from the unidirectional prediction candidate list. The adaptive weighting process is performed on the diagonal edge after the samples that are associated with each triangular prediction unit have been predicted, for example, by motion compensation or image intra-prediction. The conversion and quantization process is then applied to the entire CU. It should be noted that this mode only applies to skip mode and merge mode.

In the triangular prediction mode, a block is divided into two triangular parts (as in FIG. 7), and each part can be predicted using one motion vector. The motion vector that is used to predict one triangular portion (denoted PU1) may be different from the motion vector that is used to predict another triangular portion (denoted PU2). In the example, it is noted that each part can be predicted using only one motion vector (unidirectional prediction) to reduce the complexity of performing the triangular prediction mode. In other words, PU1 and PU2 may not be predicted using bidirectional prediction that contains two motion vectors.

Sub-block prediction mode

Triangular prediction mode is a special case of sub-block prediction where a block is divided into two blocks. The examples above illustrate two directions for dividing blocks (45 degree and 135 degree sections). Other split angles and split proportions for sub-block prediction are also possible (examples in FIG. 8).

In some examples, a block is split into 2 sub-blocks and each part (sub-block) is predicted using unidirectional prediction.

In the example, according to the use of sub-block partitioning mode, the following steps are applied to obtain prediction samples for a block:

- Stage 1: dividing the coding block into 2 subblocks according to the geometric model. This model may result in the block being divided by a demarcation line (eg, a straight line), as shown in the examples in FIGS. 9-12.

It can be understood that the output of Stage 1 may simply be a conceptual representation. For example, after Stage 1 there is no explicit "subblock 1" or "subblock 2" object; and parameters related to the demarcation line are generated and obtained. The samples belong to different sub-blocks according to the mentioned parameters related to the demarcation line.

At this stage, according to the geometric model, the samples in the encoding block are considered to be in two sub-blocks. Subblock A or subblock B may contain some (but not all) of the samples in the current encoding block. Subblock A or subblock B can be represented according to the sample_dist sign of each of the samples. Sample_dist can be obtained according to the examples and embodiments in other paragraphs.

- Step 2: obtaining the first prediction mode for the first sub-block and the second prediction mode for the second sub-block. In one example, the first prediction mode is not identical to the second prediction mode. In one example, the prediction mode (the first prediction mode or the second prediction mode) may be an inter-prediction mode, the information for the inter-prediction mode may include a reference image index and a motion vector. In another example, the prediction mode may be an intra-prediction mode, the information for the intra-prediction mode may include an index of the intra-prediction mode.

- Step 3: Obtaining the first prediction values and the second prediction values using the first prediction mode and the second prediction mode, respectively.

- Step 4: obtaining the combined values of the prediction samples in accordance with the combining of the first prediction values and the second prediction values, according to the division that is disclosed in Step 1. The process of combining the samples from the first prediction and the second prediction to obtain the combined values of the block prediction samples may include filtering operations , masking operations or copying selections.

In the example, in step 1, the encoding block is divided into 2 sub-blocks in different ways. In FIG. 9 shows an example of dividing a coding block, the demarcation line 1250 divides the block into 2 sub-blocks. To describe said line 1250, two parameters are signaled, one parameter is the angle alpha 1210 and the other parameter is the distance dist 1230.

In some embodiments, said angle, as shown in Figure 9, is measured between the x-axis and the demarcation line, while said distance is measured by the length of a vector that is perpendicular to the demarcation line and passes through the center of the current block.

In another example in FIG. 10 shows an alternative way of representing a demarcation line, where the examples of angle and distance differ from the examples shown in FIG. 9.

In some example, in Step 4, the division disclosed in Step 1 is used to combine the two mentioned predictions to obtain the final prediction. In the example, a blending operation is applied in step 4 to remove any artifacts (a sharp or jagged appearance along the demarcation line). The mixing operation can be described as a filtering operation along a line of demarcation.

In the example, on the encoder side, the demarcation line (parameters that define this line, such as angle and distance) is determined based on a cost function based on the rate-distortion relationship. Certain line parameters are encoded into a bit stream. At the decoder side, the line parameters are decoded (obtained) according to the bit stream. On the decoder side, line parameters are used to combine the first prediction values and the second prediction values to obtain the final prediction values. Stage 1 does not require two encoding subblock objects; the decoder can use the encoding block and line parameters to represent the two encoding subblock objects.

Since there are many possibilities for dividing a coding block into 2 sub-blocks, signaling (coding) such a division requires too many bits. And since the angle and distance values can have many different values, too much auxiliary information needs to be signaled in the bitstream.

Embodiments of the present invention relate to signaling of separation parameters. Efficient coding is achieved by the following features:

- Parameters (such as angle and distance) for block division are stored in a predefined table, so that the actual angle and distance values do not need to be transferred.

- The table mentioned contains the splitting parameters that are most likely and which include sufficient variation.

- The index into the table is encoded into a bit stream (or obtained from it).

Embodiments of the invention provide a method for jointly encoding parameters that describe the division of an encoding block into subblocks.

Option 1 (from the decoder position):

In this embodiment, the following steps are applied to obtain a combined prediction value for some sample from the encoding block.

Step 1: Obtain the pointer value for the current decoding block according to the bitstream.

In an embodiment, the pointer value is used to specify the shape of the split in geometric split merge mode. For example, the pointer could be merge_gpm_partition_idx[x0][y0 ], where merge_gpm_partition_idx[ x0 ][ y0 ] specifies the partition form of the geometric partition merge mode. The array indices x0, y0 specify the location (x0, y0) of the top left luminance sample of the encoding block in question relative to the top left luminance sample of the image.

Typically the merge_gpm_partition_idx[ x0 ][ y0 ] value is decoded from the bitstream. In the example, the range of values for merge_gpm_partition_idx[ ][ ] is from 0 to 63, including 0 and 63. In the example, the decoding process for merge_gpm_partition_idx[ ][ ] is "bypass".

When merge_gpm_partition_idx[ x0 ][ y0 ] is not present, it is assumed to be 0.

Step 2: Based on the pointer value and the predefined lookup table, obtain the value of the first parameter and the value of the second parameter.

(Parameter1, parameter2)=lookupTable (pointer)

In an embodiment, the partition angle variable angleIdx (parameter 1) and the distance variable distanceIdx (parameter 2) of the geometric partition mode are set according to the value of merge_gpm_partition_idx[ xCb ][ yCb ] (pointer) as specified in the following table. It can be understood that in the mentioned implementation, this relationship may be implemented according to Table 1 or according to some function.

Table 1: Specification of angleIdx and distanceIdx based on merge_gpm_partition_idx

merge_gpm_partition_idx 0 1 2 3 4 5 6 7 8 9 10 eleven 12 13 14 15 angleIdx 0 0 2 2 2 2 3 3 3 3 4 4 4 4 5 5 distanceIdx 1 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 merge_gpm_partition_idx 16 17 18 19 20 21 22 23 24 25 26 27 28 29 thirty 31 angleIdx 5 5 8 8 eleven eleven eleven eleven 12 12 12 12 13 13 13 13 distanceIdx 2 3 1 3 0 1 2 3 0 1 2 3 0 1 2 3 merge_gpm_partition_idx 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 angleIdx 14 14 14 14 16 16 18 18 18 19 19 19 20 20 20 21 distanceIdx 0 1 2 3 1 3 1 2 3 1 2 3 1 2 3 1 merge_gpm_partition_idx 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 angleIdx 21 21 24 24 27 27 27 28 28 28 29 29 29 thirty thirty thirty distanceIdx 2 3 1 3 1 2 3 1 2 3 1 2 3 1 2 3

Step 3: For a sample in the current decoding block, the sampling distance (sample_dist) is calculated according to the value of the first parameter and the value of the second parameter.

In an embodiment, step 3 comprises:

Step 3.1: getting the index value of the angle parameter (alphaN or angleIdx) for the current block, the width (W) value of the current block, the height (H) value of the current block. W and H represent the width and height of the current block by the number of samples. For example, a coding block whose width and height are 8 is a square block containing 64 samples. In another example, W and H represent the width and height of the current block by the number of brightness samples. The index value of the angle parameter can be obtained according to the above description referring to Table 1.

Step 3.2: Obtaining the whRatio value according to the W value and the H value, the whRatio value represents the ratio between the width and height of the current encoding block.

In the example whRatio=H/W; or whRatio=W/H.

In another example, two variables nCbW and nCbH specify the width and height of the current encoding block, and the variable cIdx specifies the color component index.

The variables nW, nH and whRatio are output as follows:

nW=( cIdx== 0 ) ? nCbW : nCbW * SubWidthC;

nH=( cIdx== 0 ) ? nCbH : nCbH * SubHeightC;

whRatio=nH/nW.

In the example, the variables SubWidthC and SubHeightC are specified in Table 2 depending on the chroma format sample structure, which is specified using chroma_format_idc (chroma_format_idc specifies the chroma sample relative to the luminance sample) and separate_colour_plane_flag (separate_colour_plane_flag equal to 1 specifies that the three color components of the chroma 4 :4:4 are encoded separately. separate_colour_plane_flag equal to 0 specifies that these color components are not encoded separately. When separate_colour_plane_flag is not present, it is implied to be 0. When separate_colour_plane_flag is equal to 1, the encoded image consists of three separate components, each of which consists of encoded samples of a single color plane (Y, Cb or Cr) and uses monochrome encoding syntax, in which case each color plane is associated with a specific color_plane_id value). Other values for chroma_format_idc, SubWidthC and SubHeightC may be specified in the future by ITU-T | ISO/IEC.

Table 2 - SubWidthC and SubHeightC values derived from chroma_format_idc and separate_colour_plane_flag

chroma_format_idc separate_colour_plane_flag Color Format SubWidthC SubHeightC 0 0 Monochrome 1 1 1 0 4:2:0 2 2 2 0 4:2:2 2 1 3 0 4:4:4 1 1 3 1 4:4:4 1 1

In a monochrome sample there is only one sample array, which is nominally considered the luma array.

In a 4:2:0 sample, each of the two chroma arrays is half the height and half the width of the luma array.

In a 4:2:2 sample, each of the two chroma arrays has the same height and half the width of the lumina array.

In a 4:4:4 sample, depending on the value of separate_colour_plane_flag, the following applies:

- If separate_colour_plane_flag is 0, each of the two chroma arrays has the same height and width as the luminance array.

- Otherwise (separate_colour_plane_flag is equal to 1) the three color planes are treated separately as monochrome sampled images.

Step 3.3: Retrieving the shiftHor value according to the lookup table, alpha value and whRatio value, in the example the alpha value (alphaN or angleIdx) and whRatio value are used as index values of the lookup table. It should be understood that the value of shiftHor can also be obtained according to a function, wherein the alpha value (alphaN or angleIdx) and the whRatio value represent the input to the function, and the shiftHor value represents the output of the function. In the example, the function result is the same as or the same as the lookup table. In the example, the value shiftHor represents the quantization step size for the sampling distance calculation process.

In another example, the function could be represented as shiftHor=( angleIdx % 16== 8 | | ( angleIdx % 16 != 0 && whRatio > 0 ) ) ? 0 : 1.

Step 3.4: The value of sample_dist is calculated according to the value of shiftHor.

In the example, to calculate the sample distance (sample_dist), the offsetX and offsetY variables are first output as follows:

If shiftHor is 0, the following applies:

offsetX=( −nW ) >> 1,

offsetY=( ( −nH ) >> 1 ) + ( angleIdx < 16 ? ( distanceIdx * nH ) >> 3 : −( ( distanceIdx * nH ) >> 3 ) );

Otherwise (shiftHor is 1), the following applies:

offsetX=( ( −nW ) >> 1 ) + ( angleIdx < 16 ? ( distanceIdx * nW ) >> 3 : −( ( distanceIdx * nW ) >> 3 ) );

offsetY=( − nH ) >> 1;

- Variables xL and yL are output as follows:

xL=( cIdx== 0 ) ? x : x * SubWidthC

yL=( cIdx== 0 ) ? y : y * SubHeightC

sample_dist=( ( ( xL+offsetX ) << 1 ) + 1 ) * disLut[ displacementX ] + ( ( ( yL + offsetY )  << 1 ) + 1 ) ) * disLut[ displacementY ].

The displacementX and displacementY variables are output as follows:

hwRatio=cbHeight/cbWidth;

displacementX=angleIdx;

displacementY=( angleIdx+8 ) % 32.

The disLut array is specified in Table 3 as follows:

Table 3 Specification of the disLut array of geometric separation distances

idx 0 2 3 4 5 6 8 10 eleven 12 13 14 disLut[idx] 8 8 8 4 4 2 0 −2 −4 −4 −8 −8 idx 16 18 19 20 21 22 24 26 27 28 29 thirty disLut[idx] −8 −8 −8 −4 −4 −2 0 2 4 4 8 8

In another embodiment, in an example, Step 3 in the above embodiments may comprise the following steps:

Step 3.1: getting the angle parameter value (alphaN or angleIdx) for the current block, the distance index value (distanceIdx), the width (W) value of the current block, the height (H) value of the current block. W and H represent the width and height of the current block by the number of samples. For example, a coding block whose width and height are 8 is a square block containing 64 samples. In another example, W and H represent the width and height of the current block by the number of brightness samples. The index value of the angle parameter can be obtained according to the above description referring to Table 1.

Step 3.2: Obtaining the whRatio value according to the W value and the H value, the whRatio value represents the ratio between the width and height of the current encoding block.

In the example whRatio=H/W; or whRatio=W/H.

In another example, two variables nCbW and nCbH specify the width and height of the current encoding block, and the variable cIdx specifies the color component index.

The variables nW, nH and whRatio are output as follows:

nW=( cIdx== 0 ) ? nCbW : nCbW * SubWidthC;

nH=( cIdx== 0 ) ? nCbH : nCbH * SubHeightC;

whRatio=nH/nW.

Step 3.3: Retrieving the shiftHor value according to the lookup table, alpha value and whRatio value, in the example, alphaN value and whRatio value are used as index values of the lookup table. In the example, the value shiftHor represents the quantization step size for the sampling distance calculation process. The shiftHor value can also be obtained according to a function, wherein the alpha value (alphaN or angleIdx) and the whRatio value represent the input of the function, and the shiftHor value represents the output of the function. In the example, the function result is the same as or the same as the lookup table. In the example, the value shiftHor represents the quantization step size for the sampling distance calculation process.

In another example, the function could be represented as shiftHor=( angleIdx % 16== 8 | | ( angleIdx % 16 != 0 && whRatio > 0 ) ) ? 0 : 1.

Step 3.4: Calculate sample_dist value according to shiftHor value, distanceIdx value, angle value (alphaN or angleIdx), W value and H value.

In the example, to calculate the sample distance (sample_dist), the offsetX and offsetY variables are first output as follows:

If shiftHor is 0, the following applies:

offsetX=( −nW ) >> 1,

offsetY=( ( −nH ) >> 1 ) + ( angleIdx < 16 ? ( distanceIdx * nH ) >> 3 : −( ( distanceIdx * nH ) >> 3 ) );

Otherwise (shiftHor is 1), the following applies:

offsetX=( ( −nW ) >> 1 ) + ( angleIdx < 16 ? ( distanceIdx * nW ) >> 3 : −( ( distanceIdx * nW ) >> 3 ) );

offsetY=( − nH ) >> 1;

- Variables xL and yL are output as follows:

xL=( cIdx== 0 ) ? x : x * SubWidthC

yL=( cIdx== 0 ) ? y : y * SubHeightC

sample_dist=( ( ( xL+offsetX ) << 1 ) + 1 ) * disLut[ displacementX ] + ( ( ( yL + offsetY )  << 1 ) + 1 ) ) * disLut[ displacementY ].

The displacementX and displacementY variables are output as follows:

hwRatio=cbHeight/cbWidth;

displacementX=angleIdx;

displacementY=( angleIdx+8 ) % 32.

The disLut array is specified in Table 3 above.

Step 4: Using the calculated sample_dist to calculate weights, the weights being used to combine the first prediction value and the second prediction value corresponding to said sample. In the example, the weights are denoted as sampleWeight1 and sampleWeight2, meaning a weight corresponding to the first prediction value and a weight corresponding to the second prediction value.

In one example, the weights are calculated according to the following functions

weightIdxL=partFlip ? 32+sample_dist : 32 − sample_dist;

wValue=Clip3( 0, 8, ( weightIdxL+4 ) >> 3 ).

In this example, wValue represents sampleWeight1 and 8-wValue represents sampleWeight2. The partFlip variable is defined according to the angleIdx value. In the example, partFlip=( angleIdx >= 13 && angleIdx <= 27 ) ? 0 : 1, or partFlip=( angleIdx >= 13 && angleIdx <= 27 ) ? 10.

Step 5: Calculate the combined prediction sample value at sample coordinate (x, y) according to the first prediction value at (x, y) coordinate, second prediction value at (x, y) coordinate, sampleWeight1 and sampleWeight2.

In the example, the prediction sample value is output as follows:

pbSamples[ x ][ y ]=Clip3( 0, ( 1 << BitDepth ) − 1, ( predSamplesLA[ x ][ y ] * wValue + predSamplesLB[ x ][ y ] * ( 8 − wValue ) + offset1 ) >>> shift1).

In this case, bitDepth represents the bit depth of the sample, the shift1 variable is obtained according to the mentioned bitDepth, in the example shift1= Max( 5, 17 - BitDepth ); The variable offset1 is obtained according to shift1, in the example offset1= 1 << ( shift1-1 ), predSamplesLA and predSamplesLB are two (nCbW)x(nCbH) arrays.

Option 2 (from the encoder's perspective):

In this embodiment, the following steps apply.

Step 0: Selecting the value of the first parameter and the value of the second parameter, in the example, the value of the first parameter and the value of the second parameter are obtained according to the speed-distortion metric.

Step 1: Obtaining the index value according to the value of the first parameter, the value of the second parameter and according to the lookup table so that:

(Parameter1, parameter2)=lookupTable (index)

Step 2: Encoding the index value into the bit stream.

Optionally, this embodiment uses the following steps:

Step 3: For a sample in the encoding block, calculate the sampling distance (sample_dist) according to the value of the first parameter and the value of the second parameter.

Step 4: Use the calculated sample_dist to calculate weights to combine the first prediction value and the second prediction value corresponding to said sample. The weights are denoted as sampleWeight1 and sampleWeight2, referring to the weight value corresponding to the first prediction value and the weight value corresponding to the second prediction value.

Step 5: Calculate the combined prediction value for the sample at (x, y) coordinate according to the first prediction value at (x, y) coordinate, the second prediction value at (x, y) coordinate, sampleWeight1 and sampleWeight2.

The details for each stage on the encoder side are consistent with the examples above describing the decoder side.

According to the example, the lookup table in Embodiment 1 is the same as the lookup table in Embodiment 2, so that the encoder and the decoder can obtain the same result.

In some examples, the distance value may represent a horizontal distance or a vertical distance, or a combination of a vertical and a horizontal distance, from said sample to a demarcation line (the demarcation line is used to divide a coding block into two sub-blocks). Said sample is represented by coordinates (x, y) relative to the top left sample of the encoding block. An example sample coordinate and sample_dist are shown in FIG. 11 and Fig. 12.

In the example, the first parameter represents the quantized angle value (angleIdx) and the second parameter represents the quantized distance value (distanceIdx). These two parameters describe the equation of the line. In the example, distance 1230 can be obtained according to distanceIdx (second parameter), and angle alpha (1210) can be obtained according to angleIdx (first parameter). Distance 1230 may be the distance to the center of the coding block, and the angle may be the angle between the demarcation line and a horizontal (or, equivalently, vertical) line passing through the center point of the coding block.

In one example, the lookup table is predefined.

The example may have more than one predefined lookup table. In an example, one lookup table is used for an encoding block if the aspect ratio (aspect ratio=W>H ? W/H : H/W) of the block is 1. In another example, one or more lookup tables (which are not identical to said one lookup table) are used if the aspect ratio is not 1, where W and H are the width and height of the encoding block.

In another example, there may be more than one predefined lookup table, one lookup table for encoding blocks, the block's W*H exceeds a threshold; and one or more lookup tables (which are not identical to said one lookup table) are used for a block if the block's W*H is less than or equal to a threshold. For example, if the size of the current block to be predicted is less than or equal to 32x32 luminance samples, the first lookup table is used. Otherwise, if the size of the current encoding block is greater than 32x32 luminance samples, the second lookup table is used. These two lookup tables may contain different sets of parameters for different properties of different block sizes. For example, the second lookup table may contain more parameters than the first lookup table to provide greater partitioning flexibility for larger blocks.

In some examples, if more than 1 predefined lookup table is used for a block, the function f(W, H) can be used to define one lookup table for that block, where W and H are the width and height of the encoding block.

In another example, the sampling distance sample_dist is calculated using the formula:

sample_dist=((x<<1) + 1)*Dis[angleIdx1] + ((y<<1) + 1))*Dis[angleIdx2] - offset(distanceIdx). Where

- The value of angleIdx1 and the value of angleIdx2 are taken from the bitstream or output/calculated based on other information obtained from the bitstream, angleIdx1 and angleIdx2 represent the quantized trigonometric parameters of the demarcation line, the first is of cosine type and the second is of sine type. In the example, x and y are the -x and -y sample coordinates relative to the top left sample of the encoding block.

- Dis[] is a lookup table. Dis[angleIdx1] describes the change in sample distance (sample_dist) relative to a unit increment (increase with a value of 1) -x coordinate of said sample. Dis[angleIdx2] describes the change in sample distance (sample_dist) relative to a unit increment (increase with a value of 1) -y coordinate of said sample. In one example, angleIdx1 is equal to angleIdx and angleIdx2 is equal to (displacementX+8)%32.

- offset (distanceIdx) is an offset value that is a function of the index value (distanceIdx), where the index value is obtained from the bitstream or is inferred/computed based on other information obtained from the bitstream.

Building a lookup table:

According to one example, the range of values for the first parameter may be from 0 to 4K-1, where K is an integer that is greater than 0; the range of values for the second parameter may be from 0 to N. In this case, the rows of said lookup table may include all combinations of the first parameter and the second parameter, except for the combinations:

- First set of pairs: the value of the second parameter is 0, and the value of the first parameter is one of {0, K, 2K, 3K}.

- Second set of pairs: the value of the second parameter=0, the value of the first parameter is one of {K/2, 3K/2, 5K/2, 7K/2}.

- Third set of parameters: second parameter value=0, first parameter value greater than or equal to 2K.

In the example, the value of K is 8 or 4. The number K describes how many discrete angle values are used to subdivide a 90-degree angle. In the example, if the K number is 8, the demarcation line can have the following angle values: 0, 11.25, 22.5, 33.75, 45, ... degrees. In another example, if the value of K is 4, then the angle values are: 0, 22.5, 45, 67.5, ... degrees.

In the example, the value of N is 4. In general, N can be an integer greater than 0.

In some embodiments, the second parameter describes the distance from the demarcation line to the center of the coding block. If the value of the second parameter is zero, this means that the demarcation line passes through the center of the coding block. If the value of the first parameter is K, this means that the demarcation line is oriented either horizontally or vertically (the angle value is 0, 90, 270, or 360 degrees). The first set of pairs is excluded from the lookup table because it would create a redundant partition, which can also be achieved by binary splitting (i.e. into two) the encoding block using a binary tree. Binary partitioning is a mechanism that divides a coding block into 2 coding blocks of equal size along a vertical or horizontal axis (rather than into sub-blocks). Therefore, according to embodiments of the present invention, the First set of pairs is excluded from the lookup table.

The second set of pairs is excluded from the lookup table because the second set of pairs would create division regions that can be achieved by the triangular prediction mode. Therefore, excluding the second set of pairs will prevent redundant subblock partitions.

The third set of pairs is excluded from the table because an angle equal to X or X+180 would create identical partitions if the second parameter were zero.

According to another example, the following pairs could be excluded from the lookup table:

- The value of the Second parameter is equal to N, and the value of the First parameter is equal to one of {K/2, 3K/2, 5K/2, 7K/2}.

- The value of the Second parameter is equal to N, and the value of the First parameter is equal to one of {K/2-1, 3K/2-1, 5K/2-1, 7K/2-1, K/2+1, 3K/2 +1, 5K/2+1, 7K/2+1}.

In some embodiments, the above pairs may be excluded from the lookup table because they create 2 sub-blocks, one of which may be too small. If the value of the first parameter is K/2, 3k/2, ...,, this means that the angle of the demarcation line is 45 degrees, 135 degrees, 225 degrees or 315 degrees. If the value of the second parameter is N (which has the highest value), then one of the subblocks will contain a small portion of one corner of the encoding block, which will be too small for the division operation.

The order of pairs in the lookup table is:

According to one example, pairs (first parameter, second parameter) may be added to the end of the lookup table if the second parameter is equal to N (where N is the highest possible value of the second parameter). In other words, if there are P pairs in which the value of the second parameter is N, then the last P entries in the lookup table may contain said P-pair. For example, if N is 4 and K is 8, then there are P=4K*1=32 parameter pairs for which the second parameter is 4.

In another example, parameter pairs are ordered according to a heuristic process. This heuristic process can be determined from training data that, for example, reflects the occurrence or use of parameter pairs in the training data set. Thus, the most frequently occurring parameter pairs are placed at the beginning of the list, and the less frequently occurring parameter pairs are placed at the end of the list.

When the second parameter is N, one subblock is smaller than the other subblock. The choice of such a split is less likely (compared to cases where the number of samples in each sub-block is closer). Moreover, an index value (lookup table) that has a higher value usually requires more bits in order to be encoded into the bitstream. Consequently, this increases compression efficiency by including less likely pairs at the end of the table, hence the beginning of the table can be allocated to more likely pairs (eg, pairs that result in more favorable subblock divisions).

Below is one example index (geo_partition_idx) and lookup table. The indicator has a value from 0 to 139, which is used to select the first parameter and the second parameter using a lookup table. An example of a lookup table is Table 4.

Table 4: Lookup table, where geo_partition_idx is the index into the table and angleIdx is the first parameter and distanceIdx is the second parameter.

geo_partition_idx angleIdx distanceIdx 0 0 1 1 0 2 2 0 3 3 0 4 4 1 0 5 1 1 6 1 2 7 1 3 8 1 4 9 2 0 10 2 1 eleven 2 2 12 2 3 13 2 4 14 3 0 15 3 1 16 3 2 17 3 3 18 3 4 19 4 1 20 4 2 21 4 3 22 4 4 23 5 0 24 5 1 25 5 2 26 5 3 27 5 4 28 6 0 29 6 1 thirty 6 2 31 6 3 32 6 4 33 7 0 34 7 1 35 7 2 36 7 3 37 7 4 38 8 1 39 8 2 40 8 3 41 8 4 42 9 0 43 9 1 44 9 2 45 9 3 46 9 4 47 10 0 48 10 1 49 10 2 50 10 3 51 10 4 52 eleven 0 53 eleven 1 54 eleven 2 55 eleven 3 56 eleven 4 57 12 1 58 12 2 59 12 3 60 12 4 61 13 0 62 13 1 63 13 2 64 13 3 65 13 4 66 14 0 67 14 1 68 14 2 69 14 3 70 14 4 71 15 0 72 15 1 73 15 2 74 15 3 75 15 4 76 16 1 77 16 2 78 16 3 79 16 4 80 17 1 81 17 2 82 17 3 83 17 4 84 18 1 85 18 2 86 18 3 87 18 4 88 19 1 89 19 2 90 19 3 91 19 4 92 20 1 93 20 2 94 20 3 95 20 4 96 21 1 97 21 2 98 21 3 99 21 4 100 22 1 101 22 2 102 22 3 103 22 4 104 23 1 105 23 2 106 23 3 107 23 4 108 24 1 109 24 2 110 24 3 111 24 4 112 25 1 113 25 2 114 25 3 115 25 4 116 26 1 117 26 2 118 26 3 119 26 4 120 27 1 121 27 2 122 27 3 123 27 4 124 28 1 125 28 2 126 28 3 127 28 4 128 29 1 129 29 2 130 29 3 131 29 4 132 thirty 1 133 thirty 2 134 thirty 3 135 thirty 4 136 31 1 137 31 2 138 31 3 139 31 4

It should be understood that Table 4 is just an example to show possible combinations of values for the first parameter and the second parameter; other implementations may use a portion of Table 4 as a lookup table to obtain the first parameter and the second parameter.

Example 1. Encoding method implemented by a decoding device, containing:

receiving bit stream;

obtaining a pointer value for the current block according to the bit stream;

obtaining the value of the first parameter for the current block and the value of the second parameter for the current block according to the pointer value and the predefined lookup table;

obtaining a sample distance value for a sample that is in the current block according to the value of the first parameter and the value of the second parameter;

obtaining a prediction value for the sample according to the sampling distance value for the sample.

Example 2: Method as in Example 1, where the first parameter represents the angle to split the current block.

Example 3: Method as in Example 1 or 2, in which the second parameter represents the distance to split the current block.

Example 4. The method as in any one of Examples 1 to 3, wherein the predefined lookup table consists of pairs of first and second parameters (in the example, each entry in the table is a unique pair of the first parameter and the second parameter),

the following pair is in the predefined lookup table:

the first parameter represents an angle corresponding to one of 0, 45, 90, 135, 180, 225, 270, or 315 degrees, and the corresponding second parameter in that pair does not represent a distance of zero samples from the center of the current block.

Example 5. The method as in any one of Examples 1 to 4, wherein the predefined lookup table consists of pairs of first and second parameters (in the example, each entry in the table is a unique pair of the first parameter and the second parameter),

the next pair is in a predefined lookup table;

the first parameter represents an angle other than one of 0, 45, 90, 135, 180, 225, 270, or 315 degrees, and the corresponding second parameter in the pair represents a distance of zero samples from the center of the current block.

Example 6. The method as in any one of Examples 1 to 5, wherein the predefined lookup table consists of pairs of first and second parameters (in the example, each entry in the table is a unique pair of the first parameter and the second parameter),

the next pair is not contained in the predefined lookup table;

the first parameter represents an angle corresponding to one of 0, 45, 90, 135, 180, 225, 270, or 315 degrees, and the corresponding second parameter in this pair represents the distance of zero samples from the center of the current block.

Example 7 A decoder (30) containing processing circuitry for performing the method of any one of Examples 1 to 6.

Example 8. A computer program product containing program code for executing the method of any of Examples 1 to 6.

Example 9. Decoder containing:

one or more processors; And

a non-transitory computer-readable medium coupled to the processors and storing a program portion for execution by the processors, wherein the program portion, when executed by the processors, configures a decoder to perform the method according to any of Examples 1 to 6.

Below is an explanation of the applications of the encoding method as well as the decoding method shown in the above-described embodiments, as well as the system using them.

FIG. 13 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. , computer or laptop, video conferencing system, PDA, 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. Terminal device 3106 may be a device capable of receiving and retrieving data, such as a smartphone or tablet 3108, computer or laptop 3110, network video recorder (NVR)/digital video recorder (DVR) 3112, television 3114, set-top box (STB) 3116, video conferencing system 3118 , a video surveillance system 3120, a personal digital assistant (PDA) 3122, a 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, an image encoding device or an image decoding device may be used as shown in the above embodiments.

FIG. 14 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.

Through demultiplexing processing, an elementary video stream (ES), audio ES, and optionally subtitles are generated. The video decoder 3206, which includes the video decoder 30 described in the above embodiments, decodes the video ES 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 the audio ES to generate an audio frame and supplies this data to synchronization block 3212. Alternatively, the video frame may be stored in a buffer (not shown in FIG. 14) before being supplied to synchronization block 3212. Likewise, an audio frame may be stored in a buffer (not shown in FIG. 14) 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 a subtitle is included in the stream, the subtitle decoder 3210 decodes the subtitle and synchronizes it with the video frame and audio frame and transmits the video/audio/subtitle to the video/audio/subtitle display 3216.

The present invention is not limited to the above system, and either the image encoding device or the image decoding device from the above embodiments can be included in another system, such as an automobile system.

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" between x and y

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

! - Boolean logical "not"

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

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

Bitwise operators

The following bitwise operators are defined as follows:

& Bitwise "and". When working with 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.

| Bitwise "or". When working with 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.

^ Bitwise exclusive OR. When working with 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. Bits shifted to the most significant bits (MSB) by a right shift have a value equal to MSB 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, takes the value of the variable before the increment operation.

−− Decrease, i.e. x−− is equivalent to x = x- 1; when used in an array index, takes the value of the variable 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..z x 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 -1.0 to 1.0 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 ) is the smallest integer greater than or equal to x.

Clip1 _Y ( x ) = Clip3( 0, ( 1 << BitDepth _Y ) − 1, x )

Clip1 _C ( x ) = Clip3( 0, ( 1 << BitDepth _C ) − 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 2.718 281 828 ...).

Log2( x ) logarithm of x to base 2.

Log10( x ) is the logarithm of x to base 10.

Min( x, y ) =

Max( x, y ) =

Round( x ) = Sign( x ) * Floor( Abs( x ) + 0.5 )

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: Operation priority from highest (at the top of the table) to lowest (at the bottom of the table)

operations (with 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 )

definition 0

else if( condition 1 )

definition 1

...

else /* informative comment on the remaining condition */

definition of n

can be described as follows:

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

- If condition 0, definition 0

- Otherwise, If condition 1, definition 1

- ...

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

Each definition of "If...Else, If...Else,..." in the text is introduced by the words "...as below" or "...the following applies" followed immediately by "If..." . The last condition of "If... Else, If... Else, ..." is always "Else, ...". Alternating definitions "If...Else, If...Else,..." can be identified by matching "...as below" 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 )

definition 0

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

definition 1

...
else
definition of n

can be described as follows:

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

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

-- condition 0a

-- condition 0b

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

-- condition 1a

-- condition 1b

- ...

- Otherwise, the definition of n

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

if( condition 0 )

definition 0

if( condition 1 )

definition 1

can be described as follows:

When condition is 0, definition is 0

When condition is 1, definition is 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 be used 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 loop 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 techniques 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 disc and disc used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where discs are 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 techniques 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 techniques may be fully implemented in one or more circuits, or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or hardware components, including a wireless telephone, 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.

Claims (41)

1. A decoding method implemented by a decoding device, containing: receiving bit stream; And performing decoding by: obtaining a pointer value for the current block according to the bit stream; obtaining the value of the first parameter for the current block and the value of the second parameter for the current block according to the pointer value and the predefined lookup table; obtaining a sample distance value for a sample that is in the current block according to the value of the first parameter and the value of the second parameter; And obtaining the prediction value for the sample according to the sampling distance value for the sample, in this case the predefined lookup table is merge_gpm_partition_idx 0 1 2 3 4 5 6 7 8 9 10 eleven 12 13 14 15 angleIdx 0 0 2 2 2 2 3 3 3 3 4 4 4 4 5 5 distanceIdx 1 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 merge_gpm_partition_idx 16 17 18 19 20 21 22 23 24 25 26 27 28 29 thirty 31 angleIdx 5 5 8 8 eleven eleven eleven eleven 12 12 12 12 13 13 13 13 distanceIdx 2 3 1 3 0 1 2 3 0 1 2 3 0 1 2 3 merge_gpm_partition_idx 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 angleIdx 14 14 14 14 16 16 18 18 18 19 19 19 20 20 20 21 distanceIdx 0 1 2 3 1 3 1 2 3 1 2 3 1 2 3 1 merge_gpm_partition_idx 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 angleIdx 21 21 24 24 27 27 27 28 28 28 29 29 29 thirty thirty thirty distanceIdx 2 3 1 3 1 2 3 1 2 3 1 2 3 1 2 3 where the pointer is merge_gpm_partition_idx, where the first parameter is angleIdx, which represents the angle to split the current block, where the second parameter is distanceIdx, which represents the distance to split the current block. 2. The method according to claim 1, in which the second parameter specifies the distance index of the geometric section, or the second parameter describes the distance from the demarcation line to the center of the current block. 3. Method according to any one of paragraphs. 1, 2, wherein obtaining a prediction value for a sample according to a sampling distance value for a sample comprises: calculating two weight coefficients according to the sampling distance value; And obtaining a prediction value for the sample according to the first prediction value, the second prediction value, and the two weights. 4. Method according to any one of paragraphs. 1-3, wherein the sample distance value represents a horizontal distance or a vertical distance, or a combination of vertical and horizontal distances from said sample to a demarcation line, wherein the demarcation line is used to divide a coding block into two sub-blocks. 5. Method according to any one of paragraphs. 1-4, in which the predefined lookup table contains pairs of first and second parameters, provided that when the first parameter in a pair represents an angle corresponding to one of 0, 45, 90, 135, 180, 225, 270 or 315 degrees, the corresponding second parameter in that pair does not represent a distance of zero samples from the center of the current block. 6. The method according to any one of claims 1 to 5, wherein the predefined lookup table contains pairs of first and second parameters, wherein the first parameter in the pair represents an angle other than one of 0, 45, 90, 135, 180, 225, 270, or 315 degrees, and the corresponding second parameter in the pair represents a distance of zero samples from the center of the current block. 7. The method according to any one of claims 1 to 6, wherein the predefined lookup table contains pairs of first and second parameters, wherein the first parameter in the pair represents an angle corresponding to one of 0, 45, 90, 135, 180, 225, 270, or 315 degrees, and the corresponding second parameter in the pair represents a distance of zero samples from the center of the current block. 8. A decoder (30) comprising a processing circuit for performing the method according to any one of claims. 1-7. 9. Decoder containing: one or more processors; And a non-transitory computer-readable medium coupled to the processors and storing a program portion for execution by the processors, wherein the program portion, when executed by the processors, configures a decoder to perform the method of any one of claims 1 to 7. 10. An encoding method implemented by an encoding device, containing: selecting the value of the first parameter and the value of the second parameter; obtaining an index value according to the first parameter value, the second parameter value and the lookup table; And encoding the index value into a bit stream, in this case the predefined lookup table is merge_gpm_partition_idx 0 1 2 3 4 5 6 7 8 9 10 eleven 12 13 14 15 angleIdx 0 0 2 2 2 2 3 3 3 3 4 4 4 4 5 5 distanceIdx 1 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 merge_gpm_partition_idx 16 17 18 19 20 21 22 23 24 25 26 27 28 29 thirty 31 angleIdx 5 5 8 8 eleven eleven eleven eleven 12 12 12 12 13 13 13 13 distanceIdx 2 3 1 3 0 1 2 3 0 1 2 3 0 1 2 3 merge_gpm_partition_idx 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 angleIdx 14 14 14 14 16 16 18 18 18 19 19 19 20 20 20 21 distanceIdx 0 1 2 3 1 3 1 2 3 1 2 3 1 2 3 1 merge_gpm_partition_idx 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 angleIdx 21 21 24 24 27 27 27 28 28 28 29 29 29 thirty thirty thirty distanceIdx 2 3 1 3 1 2 3 1 2 3 1 2 3 1 2 3 where the index value is merge_gpm_partition_idx, where the first parameter is angleIdx, which represents the angle to partition the current block, where the second parameter is distanceIdx, which represents the distance to partition the current block. 11. The method according to claim 10, wherein the method additionally contains: calculating a sampling distance for a sample in the encoding block; calculating weights corresponding to the sample according to the calculated sampling distance; And calculating a combined prediction value for the sample according to the first prediction value, the second prediction value, and said weights. 12. Encoder containing: one or more processors; And a non-transitory computer-readable medium coupled to the processors and storing a program portion for execution by the processors, wherein the program portion, when executed by the processors, configures the encoder to perform the method of claim 10 or 11. 13. A computer-readable medium containing processor-executable instructions for performing the method of any one of claims 1 to 7. 14. A computer-readable medium containing processor-executable instructions for performing the method of any one of claims 10-11.

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