WO2020125761A1

WO2020125761A1 - Image block division method and device

Info

Publication number: WO2020125761A1
Application number: PCT/CN2019/127075
Authority: WO
Inventors: 赵寅; 杨海涛; 张恋
Original assignee: 华为技术有限公司
Priority date: 2018-12-22
Filing date: 2019-12-20
Publication date: 2020-06-25

Abstract

Provided are an image block division method and device. The method comprises: acquiring block information of a current image block in a current image; determining, according to the block information, whether the current image block exceeds the boundary of the current image; if the current image block exceeds the boundary of the current image, determining a mandatory division method for the current image block; and dividing the current image block according to the mandatory division method. In the present application, by means of determining a mandatory division method for the current image block that exceeds the boundary of the current image, the computational complexity of video sequence encoding and decoding is reduced, thereby improving the compression performance.

Description

Method and device for dividing image blocks

This application requires the priority of the Chinese patent application filed on December 22, 2018, with the application number 201811575681.9, and the Chinese patent application filed with the Chinese patent office, with the application number 201910017097.X, on January 8, 2019. Incorporated by reference in this application.

Technical field

The present application relates to video image technology, and in particular, to an image block division method and device.

Background technique

Digital video capabilities can be incorporated into a variety of devices, including digital TVs, digital live broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, Digital cameras, digital recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio phones (so-called "smart phones"), video teleconferencing devices, video streaming devices, and the like . Digital video devices implement video compression technology, for example, in the standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264/MPEG-4 Part 10 Advanced Video Coding (AVC), The video compression technology described in the video coding standard H.265/High Efficiency Video Coding (HEVC) standard and extensions to such standards. Video devices can more efficiently transmit, receive, encode, decode, and/or store digital video information by implementing such video compression techniques.

Video compression techniques perform spatial (intra-image) prediction and/or temporal (inter-image) prediction to reduce or remove redundancy inherent in video sequences. For block-based video coding, a video slice (ie, a video frame or a portion of a video frame) can be divided into several image blocks, which can also be called tree blocks, coding units (CU, Coding Units), and/or Or coding block. The image block in the to-be-intra-coded (I) slice of the image is encoded using spatial prediction regarding reference samples in adjacent blocks in the same image. An image block in an inter-coded (P or B) slice of an image may use spatial prediction relative to reference samples in neighboring blocks in the same image or temporal prediction relative to reference samples in other reference images. The image may be referred to as a frame, and the reference image may be referred to as a reference frame.

However, when dividing an image block during the encoding of a video sequence, to determine the division method of an image block, the rate-distortion costs corresponding to multiple division methods need to be calculated first, and the rate-distortion cost of each image block can be determined after comparing the rate-distortion costs. Optimal division method; when dividing image blocks in the process of decoding a video sequence, it is necessary to continuously analyze the division method of each image block from the code stream, and the image blocks divided according to the parsed division method can be decoded correctly. It can be seen that the image block division method in the prior art causes the calculation complexity of video sequence encoding and decoding to be too high.

Summary of the invention

The present application provides an image block division method and device, which reduces the computational complexity of video sequence encoding and decoding to a certain extent.

In the first aspect, the present application provides an image block division method, which can be applied to encoding and decoding of video sequences. Among them, the method includes: first obtaining the block information of the current image block from the current image or code stream, where the current image block is an image block of the current image; then, according to the block information of the current image block, the current image is determined Whether the block exceeds the boundary of the current image, if the current image block exceeds the boundary of the current image, then determine the mandatory division method for the current image block, and divide the current image block according to the mandatory division method;

The current image block is an image block divided by the current image, corresponding to a node on the coding tree of the current image. The current image block may be a CTU of the current image or a sub-block obtained by dividing the CTU as the root node. It can also be a sub-block of the next level obtained by dividing a sub-block of one level as the root node.

The block information of the current image block may include the size information of the current image block, such as the width and height of the current image block, and may also include the coordinates of the pixels in the current image block. Here, the coordinates of the pixels are relative to the upper left vertex of the current image. The coordinates of the pixel position. Of course, the block information can also be other image-related information corresponding to the current image block. These block information can be obtained from the current image or code stream;

The boundary of the current image may include but is not limited to: the right boundary and/or the lower boundary of the current image.

Here, it should be noted that the above-mentioned current image block beyond the current image boundary does not mean that there are still pixel values in the current image block beyond the image boundary, but it refers to the current image block in a certain direction or two directions The maximum coordinate value exceeds the coordinate value of the image boundary along the same direction.

In the present application, the forced division method means that the division method of the current image block does not need to be obtained by parsing the code stream, and the current image block is directly divided using the forced division method. The above-mentioned mandatory division method for the current image block can be and is not limited to horizontal binary tree (HBT, Horizontal Binary Tree), vertical binary tree (VBT, Vertical Binary Tree), quadtree (QT, Quad), horizontal expansion quadtree Tree (HEQT, Horizontal Extended Tree) and Vertically Extended Quad Tree (VEQT, Vertical Extended Tree) are one or more cascades of these divisions. Among them, HBT and VBT belong to binary tree (BT, Binary Tree) specific application in the division method, HEQT and VEQT belong to the specific application in the division method of Extended Quad Tree (EQT, Extended Quad Tree). For example, in the AVS3 standard, QT concatenated BT/EQT is used, that is, the nodes on the first level coding tree can only be divided into child nodes using QT, and the child nodes of the first level coding tree are the second level coding tree The root node of the second level coding tree can be divided into child nodes using one of the BT or EQT division methods. It should be noted that when a child node uses BT or EQT division, its child nodes can only use BT or EQT division, but not QT division.

In this application, in the current image, when scanning according to the zigzag (Zigzag), when an image block in the current image is scanned, that is, the current image block, the current image is parsed from the current image or from the code stream The block information of the image block, then, based on these block information, determine whether the current image block exceeds the boundary of the current image, and determine the forced division method for the current image block that exceeds the boundary of the current image, and perform forced division in this way to avoid encoding In order to determine the optimal division method of the current image block, the end calculates the rate-distortion cost multiple times, and the decoding end does not need to continuously parse the current image block division method from the code stream, thereby reducing the calculation complexity of the video sequence codec and improving compression performance.

Based on the first aspect, in some possible implementations, determining the forced division method for the current image block includes: comparing the size information of the current image block with a preset threshold, and determining the corresponding forced division method and size for the current image block The information is obtained from the block information.

In this application, the above-mentioned preset threshold can be set in the video encoder or video decoder, or can also be parsed from the code stream. The value of the preset threshold may be different according to actual needs, and this application does not specifically limit it.

Based on the first aspect, in some possible implementations, when the current image block exceeds the right boundary of the current image, the size information of the current image block is compared with a preset threshold to determine the corresponding forced division method for the current image block, Including: if the width of the current image block is equal to the first preset threshold and the height of the current image block is greater than the first preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method; if the width of the current image block is not equal to the first A preset threshold, and the height of the current image block is less than or equal to or the first preset threshold, determine that the current image block is forcibly divided according to the VBT division method, the first preset threshold is a positive integer; or, if the width of the current image block Is equal to the second preset threshold, and the height of the current image block is equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method; if the width of the current image block is not equal to the second preset threshold, and the current image If the height of the block is not equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; the second preset threshold is less than the third preset threshold, and the second preset threshold and the third preset threshold are greater than or An integer equal to 32.

Based on the first aspect, in some possible implementations, when the current image block exceeds the lower boundary of the current image, the corresponding forced division method is determined for the current image block according to the comparison result, including: If the width of the current image block is greater than the A preset threshold, and the height of the current image block is equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; if the width of the current image block is less than or equal to the first preset threshold, and the current image block Is not equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method, the first preset threshold is a positive integer; or, if the height of the current image block is equal to the second preset threshold, and the current image block Is equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; otherwise, it is determined that the current image block is forcibly divided according to the HBT division method; the second preset threshold is less than the third preset threshold

Based on the first aspect, in some possible implementation manners, the second preset threshold is an integer greater than or equal to 32.

Based on the first aspect, in some possible implementation manners, the second preset threshold is 64, and the third preset threshold is 128.

The first preset threshold can be set in the video encoder or video decoder (for example, set to 64), or can be obtained by parsing from the code stream.

Both the second preset threshold and the third preset value can be set in the video encoder or video decoder, and can also be parsed from the code stream. The second preset threshold may be different from the third preset threshold, for example, the second preset threshold is 64 and the third preset threshold is 128, or the second preset threshold is 64 and the third preset threshold is 32, Of course, there may be a second preset threshold and a third preset threshold, and there may be other values, as long as the condition that the second preset threshold is less than the third preset threshold can be satisfied, this application does not specifically limit .

The values of the first preset threshold, the second preset threshold, and the third preset threshold can be set by those skilled in the art according to the needs of actual image division, and are not limited to the above examples.

Based on the first aspect, in some possible implementations, when the current image block exceeds the right boundary of the current image and exceeds the lower boundary of the current image, determining the forced division method for the current image block includes: The division method of QT of the cross tree.

Based on the first aspect, in some possible implementations, determining whether the current image block exceeds the boundary of the current image based on the block information includes: according to the block information, obtaining the coordinates (x, y) of a pixel in the current image block ; Determine whether the pixel coordinates (x, y) meet the preset conditions, if the pixel coordinates (x, y) meet the first preset condition, it means that the pixel exceeds the right boundary of the current image, if the pixel coordinates ( x, y) meet the second preset condition, it means that the pixel exceeds the lower boundary of the current image, if the pixel coordinate (x, y) meets the third preset condition, it means that the pixel exceeds the right boundary of the current image and exceeds The lower border of the current image.

The above pixels are used to represent the current image block. You can select specific pixels in the current image block to represent the current image block. For example, select the pixels of each vertex of the current image block, such as the pixels of the upper left vertex and the pixels of the upper right vertex. The pixel point, the pixel point of the lower left vertex or the pixel point of the lower right vertex, of course, you can also select the pixel point of the center position of the current image block. By comparing the coordinates of these pixel points with the coordinates of the boundary of the current image, it can be determined whether the current image block exceeds the boundary of the current image. Of course, in order to further improve the accuracy, any pixel in the current image block can also be selected and used to determine whether the current image block exceeds the boundary of the current image. In this application, other conditions may also be used to determine whether the current image block exceeds the boundary of the current image, which is not specifically limited.

Based on the first aspect, in some possible implementations, the coordinates (x, y) of the pixels are the coordinates of the pixel position of the upper left vertex in the current image block relative to the pixel position of the upper left vertex of the current image; accordingly, the first pre Let the condition be: the coordinates (x, y) of the pixel satisfy x+cW>picW, and y+cH≤picH; the second preset condition is: the coordinates (x, y) of the pixel satisfy x+cW≤picW, And y+cH>picH; the third preset condition is: the coordinates (x, y) of the pixel satisfy x+cW>picW, and y+cH>picH; where cW is the width of the current image block and cH is the current The height of the image block, picW is the width of the current image, and picH is the height of the current image.

The first preset condition, the second preset condition, and the third preset condition are different according to the coordinates (x, y) of the selected pixel point, and are not specifically limited in this application.

Based on the first aspect, in some possible implementations, after determining whether the current image block exceeds the boundary of the current image based on the block information, the method further includes: if the current image block does not exceed the boundary of the current image, at least according to the current image The size information of the block determines the forced division method for the current image block, and the size information is obtained from the block information; the current image block is divided according to the determined forced division method.

In this application, according to the block information of the current image block, it is determined that the current image block does not exceed the boundary of the current image. At this time, a forced division method may also be determined for the current image block, and division is performed according to the determined forced division method. Thereby further reducing the computational complexity of video sequence encoding and decoding, thereby improving the compression performance.

Based on the first aspect, in some possible implementations, at least according to the size information of the current image block, determining a mandatory division method for the current image block includes: calculating the ratio of the width and height of the current image block based on the size information; If it is greater than the fourth preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method, and the fourth preset threshold is a positive integer; if the ratio is less than the fifth preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method , The fifth preset threshold is the reciprocal of the fourth preset threshold.

The above fourth preset threshold may be set in the video encoder or video decoder, or may be parsed from the code stream. The fourth preset threshold may take a maximum ratio maxRatio, for example, 4 or 8. The fifth preset threshold can be calculated by taking the reciprocal of the fourth preset threshold, then, the fifth preset threshold can be 1/maxRatio, with a value range of (0, 1), such as 1/4 or 1/8.

Based on the first aspect, in some possible implementations, at least according to the size information of the current image block, determining a mandatory division method for the current image block includes: determining whether the current image block is an I-band or an I frame; determining the current image block Whether the width and height of are equal to the sixth preset threshold, and the sixth preset threshold is a positive integer; if the image block of the current image is I band or I frame, and the width and height of the current image block are equal to the sixth preset The threshold value determines that the current image block is forcibly divided according to the QT division method.

The above sixth preset threshold can be set in the video encoder or video decoder (for example, set to 128 or 256), or can also be parsed from the code stream.

Based on the first aspect, in some possible implementations, after at least determining the mandatory division method for the current image block according to the size information of the current image block, the method further includes: when no mandatory division method is determined for the current image block , Determine the final division mode from the division modes allowed for the current image block, and divide the current image block according to the final division mode; or, when no mandatory division mode is determined for the current image block , Dividing the current image block according to the division manner indicated by the syntax element corresponding to the current image block.

For some image blocks that do not exceed the boundary of the current image, there are cases where the size and image type do not meet the above preset conditions. At this time, it is considered that these image blocks do not have a mandatory division method, then these image blocks can be The current image block is allowed to use the division method or the division method indicated by the syntax element corresponding to the current image block.

Based on the first aspect, in some possible implementations, before dividing the current image block according to the allowed division method of the current image block, the method further includes: according to the size information of the current image block, determining that the current image block is not allowed The division method used; where, if the height of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use the HBT division method and the VEQT division method, and the seventh preset threshold value is the side length of the smallest coding unit ; If the width of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use the VBT division method and the HEQT division method; if the height of the current image block is less than or equal to the eighth preset threshold, then determine the current The image block is not allowed to use the HEQT division method. The eighth preset threshold is twice the seventh preset threshold; if the width of the current image block is less than or equal to the eighth preset threshold, it is determined that the current image block is not allowed to use VEQT Division method.

The seventh preset threshold and the eighth preset threshold may be set in the video encoder or video decoder, or may be obtained by parsing from the code stream. The seventh preset threshold may be minCUSize, which is the minimum CU side length, for example, 4 or 8. The eighth preset threshold can be obtained by calculating twice the seventh preset threshold, that is, taking minCUSize×2, for example, taking 8 or 16.

In a second aspect, the present application provides an image block division device, including several functional units for implementing any one of the methods of the first aspect. For example, the image block division device may include: an acquisition unit for acquiring block information of the current image block in the current image; a determination unit for determining whether the current image block exceeds the boundary of the current image based on the block information; a determination unit, It is used to determine the forced division mode for the current image block if the current image block exceeds the boundary of the current image; the division unit is used to divide the current image block according to the forced division mode.

Based on the second aspect, in some possible implementations, the determining unit is specifically configured to compare the size information of the current image block with a preset threshold to determine the corresponding forced division method for the current image block. The size information is determined by the block information acquired.

Based on the second aspect, in some possible implementation manners, the determining unit includes: a first determining subunit and a second determining subunit; the first determining subunit is used when the current image block exceeds the right boundary of the current image, If the width of the current image block is equal to the first preset threshold and the height of the current image block is greater than or equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method; if the width of the current image block is not equal to the first A preset threshold, and the height of the current image block is less than or equal to or the first preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method, the first preset threshold is a positive integer; the second determination subunit is used for when When the current image block exceeds the right boundary of the current image, if the width of the current image block is equal to the second preset threshold and the height of the current image block is equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method ; If the width of the current image block is not equal to the second preset threshold and the height of the current image block is not equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; the second preset threshold is less than the third Preset threshold.

Based on the second aspect, in some possible implementation manners, the determining unit includes: a third determining subunit and a fourth determining subunit; the third determining subunit is used when the current image block exceeds the lower boundary of the current image, If the width of the current image block is greater than the first preset threshold, and the height of the current image block is equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; also used if the width of the current image block is less than or Is equal to the first preset threshold, and the height of the current image block is not equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method, the first preset threshold is a positive integer; or, the fourth determination subunit , Used to determine that the current image block is forced to comply with the VBT when the width of the current image block is equal to the second preset threshold and the height of the current image block is equal to the third preset threshold when the current image block exceeds the lower boundary of the current image Divided by division method; the width of the current image block is not equal to the second preset threshold, and the height of the current image block is not equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method; the second preset threshold is less than the Three preset thresholds.

Based on the second aspect, in some possible implementation manners, the second preset threshold is an integer greater than or equal to 32.

Based on the second aspect, in some possible implementation manners, the second preset threshold is 64, and the third preset threshold is 128.

Based on the second aspect, in some possible implementations, the determining unit is specifically configured to determine that the current image block is forcibly divided according to the QT division method when the current image block exceeds the right boundary of the current image and exceeds the lower boundary of the current image.

Based on the second aspect, in some possible implementations, the judgment unit is configured to obtain the coordinates (x, y) of a pixel in the current image block according to the block information; determine whether the coordinates (x, y) of the pixel Satisfying the preset condition, if the coordinates (x, y) of the pixel point satisfy the first preset condition, it means that the pixel exceeds the right boundary of the current image, if the coordinates (x, y) of the pixel point satisfy the second preset condition, then It indicates that the pixel exceeds the lower boundary of the current image. If the coordinates (x, y) of the pixel point satisfy the third preset condition, it indicates that the pixel point exceeds the right boundary of the current image and exceeds the lower boundary of the current image.

Based on the second aspect, in some possible implementation manners, the coordinates (x, y) of the pixels are the coordinates of the pixel position of the upper left vertex in the current image block relative to the pixel position of the upper left vertex of the current image; accordingly, the first pre Let the condition be: the coordinates (x, y) of the pixel satisfy x+cW>picW, and y+cH≤picH; the second preset condition is: the coordinates (x, y) of the pixel satisfy x+cW≤picW, And y+cH>picH; the third preset condition is: the coordinates (x, y) of the pixel satisfy x+cW>picW, and y+cH>picH; where cW is the width of the current image block, and cH is the current The height of the image block, picW is the width of the current image, and picH is the height of the current image.

Based on the second aspect, in some possible implementation manners, the determining unit is further configured to determine a mandatory division method for the current image block based on the size information of the current image block at least according to the size information of the current image block, size information It is obtained from the block information; the dividing unit is also used to divide the current image block according to the determined forced division method.

Based on the second aspect, in some possible implementation manners, the determination unit further includes: a calculation subunit, a fifth determination subunit, and a sixth determination subunit; the calculation subunit is used to calculate the current image block's size based on the size information The ratio of width to height; the fifth determining subunit is used to determine that the current image block is forcibly divided according to the VBT division method if the ratio is greater than the fourth preset threshold; the fourth preset threshold is a positive integer; the sixth determining subunit Is used to determine that the current image block is forcibly divided according to the HBT division method if the ratio is less than the fifth preset threshold, and the fifth preset threshold is the reciprocal of the fourth preset threshold.

Based on the second aspect, in some possible implementation manners, the determination unit further includes: a determination subunit and a seventh determination subunit; the determination subunit is used to determine whether the current image block is an I band or an I frame; To determine whether the width and height of the current image block are equal to the sixth preset threshold, the sixth preset threshold is a positive integer; the seventh determination subunit is used if the current image block is I band or I frame, and the current image If the width and height of the block are equal to the sixth preset threshold, it is determined that the current image block is forcibly divided according to the QT division method.

Based on the second aspect, in some possible implementation manners, the dividing unit is further used to determine the final division from the division modes allowed for the current image block when the mandatory division mode is not determined for the current image block Method, and divide the current image block according to the final division method; or, when no mandatory division method is determined for the current image block, according to the division method indicated by the syntax element corresponding to the current image block, The current image block is divided.

Based on the second aspect, in some possible implementations, the dividing unit is further used to determine the current image block according to the size information of the current image block before dividing the current image block according to the allowed division method of the current image block The division method that is not allowed to be used; where, if the height of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use the HBT division method and the VEQT division method, and the seventh preset threshold value is that of the smallest coding unit Side length; if the width of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use VBT and HEQT division; if the height of the current image block is less than or equal to the eighth preset threshold, the current image is determined Blocks are not allowed to use HEQT division. The eighth preset threshold is twice the seventh preset threshold; if the width of the current image block is less than or equal to the eighth preset threshold, it is determined that the current image block is not allowed to use VEQT division the way.

In a third aspect, the present application provides a video encoding method that can be applied to a video encoder; the video encoding method includes: performing any of the image division methods described above in the first aspect to divide the current coding block; dividing the current coding block The outgoing CU performs prediction to obtain a corresponding prediction block; obtains a corresponding residual block according to the current coding block and the prediction block; entropy encodes the residual block to generate a corresponding code stream.

In a fourth aspect, the present application provides a video decoding method that can be applied to a video decoder; the video decoding method includes: performing any of the image division methods as described in the first aspect above to divide the current decoding block; dividing the current decoding block The CU is predicted to obtain the corresponding prediction block; according to the residual block and the prediction block parsed from the code stream, the current decoding block is reconstructed.

According to a fifth aspect, the present application provides a video encoder for encoding an image block, including: any one of the image block division devices of the second aspect, wherein the image block division device is used to obtain the current image from the current image The block information of the coding block, the current image block is the image block to be coded in the current image; according to the block information, it is judged whether the current coding block exceeds the boundary of the current coding image; if the current coding block exceeds the boundary of the current coding image, it is the current coding The block determines the forced division mode, and divides the current coding block according to the forced division mode; the first prediction processing unit is used to predict the CU divided by the current coding block to obtain the corresponding prediction block; the residual calculation unit is used to According to the current coding block and the prediction block, a corresponding residual block is obtained; an entropy coding unit is used to entropy encode the residual block to generate a corresponding code stream.

According to a sixth aspect, the present application provides a video decoder for decoding an image block from a code stream, including: any one of the image block division devices of the second aspect, wherein the image block division device is used for Obtain the block information of the current decoded block in the code stream. The current decoded block is the image block to be decoded in the current image; according to the block information, determine whether the current decoded block exceeds the boundary of the current decoded image; if the current decoded block exceeds the boundary of the current decoded image , Determine the mandatory division method for the current decoding block, and divide the current decoding block according to the mandatory division method; the second prediction processing unit is used to predict the CU divided by the current decoding block to obtain the corresponding prediction block; reconstruction The unit is used to reconstruct the current decoded block according to the residual block and the prediction block parsed from the code stream.

In a seventh aspect, the present application provides an apparatus for encoding video data, the apparatus includes:

A memory for storing video data, the video data including one or more image blocks;

The video encoder is used to obtain the block information of the current encoding block from the current image. The current image block is the image block to be encoded in the current image; according to the block information, determine whether the current encoding block exceeds the boundary of the current encoding image; if the current If the coding block exceeds the boundary of the current coded image, determine the mandatory division method for the current coding block, and divide the current coding block according to the mandatory division method; encode the sub-blocks divided by the current coding block to obtain the code corresponding to the current coding block flow.

In an eighth aspect, the present application provides an apparatus for decoding video data. The apparatus includes:

Memory, used to store video data in the form of code stream;

The video decoder is used to obtain the block information of the current decoding block from the code stream. The current decoding block is the image block to be decoded in the current image; according to the block information, it is determined whether the current decoding block exceeds the boundary of the current decoded image; if the current decoding If the block exceeds the boundary of the current decoded image, the forced division method is determined for the current decoded block, and the current decoded block is divided according to the forced division method; the coding information of the sub-block divided by the current decoded block is parsed from the code stream, and according to The encoded information reconstructs the current decoded block.

In a ninth aspect, the present application provides an encoding device, including: a non-volatile memory and a processor coupled to each other, and the processor calls program codes stored in the memory to perform any one of the methods of the first aspect Part or all of the steps.

According to a tenth aspect, the present application provides a decoding device, including: a non-volatile memory and a processor coupled to each other, the processor calling program code stored in the memory to perform any one of the methods of the first aspect Part or all of the steps.

According to an eleventh aspect, the present application provides a computer-readable storage medium that stores program code, where the program code includes part or all of the method for performing any one of the first aspects Step instructions.

In a twelfth aspect, the present application provides a computer program product that, when the computer program product runs on a computer, causes the computer to perform part or all of the steps of any one of the methods of the first aspect.

It should be understood that the second to twelfth aspects of the present application are consistent with the technical solution of the first aspect of the present application, and the beneficial effects obtained by the various aspects and the corresponding feasible implementation manners are similar and will not be repeated.

BRIEF DESCRIPTION

1A is a schematic diagram of an example of a video encoding and decoding system in an embodiment of this application;

1B is a schematic diagram of an example of a video decoding system in an embodiment of this application;

2 is a schematic diagram of an example structure of an encoder in an embodiment of this application;

3 is a schematic diagram of an example structure of a decoder in an embodiment of this application;

4 is a schematic diagram of an example of a video decoding device in an embodiment of this application;

5 is a schematic diagram of an example of an encoding device or a decoding device in an embodiment of this application;

FIG. 6 is a schematic diagram of a division manner of BT, QT, and EQT in an embodiment of this application;

7 is a schematic diagram of a division method based on QT-MTT in an embodiment of the present application;

8 is a schematic diagram of an implementation process of an image block division method in an embodiment of this application;

9 is a schematic diagram of the current image block exceeding the current image boundary in the embodiment of the present application;

10 is a schematic structural diagram of an image block division device in an embodiment of the present application.

detailed description

The following describes the embodiments of the present application with reference to the drawings in the embodiments of the present application. In the following description, reference is made to the accompanying drawings that form a part of the present application and illustrate specific aspects of the embodiments of the present application by way of illustration or may use specific aspects of the embodiments of the present application. It should be understood that the embodiments of the present application may be used in other aspects, and may include structural or logical changes not depicted in the drawings. Therefore, the following detailed description should not be interpreted in a restrictive sense, and the scope of the present application is defined by the appended claims. For example, it should be understood that the disclosure in conjunction with the described method may be equally applicable to the corresponding device or system for performing the method, and vice versa. For example, if one or more specific method steps are described, the corresponding device may contain one or more units such as functional units to perform the one or more method steps described (eg, one unit performs one or more steps , Or multiple units, each of which performs one or more of multiple steps), even if such one or more units are not explicitly described or illustrated in the drawings. On the other hand, for example, if a specific device is described based on one or more units such as a functional unit, the corresponding method may include a step to perform the functionality of one or more units (eg, one step executes one or more units Functionality, or multiple steps, each of which performs the functionality of one or more of the multiple units), even if such one or more steps are not explicitly described or illustrated in the drawings. Further, it should be understood that, unless expressly stated otherwise, the features of the exemplary embodiments and/or aspects described herein may be combined with each other.

The technical solutions involved in the embodiments of the present application may not only be applied to existing video coding standards (such as H.264, High Performance Video Coding (HEVC, High Efficiency, Video Coding) and other standards), but may also be applied to future video coding In the standard (such as H.266 standard). The terminology used in the embodiment section of the present application is only used to explain specific examples of the present application, and is not intended to limit the present application. The following briefly introduces some concepts that may be involved in the embodiments of the present application.

Video coding generally refers to processing a sequence of pictures that form a video or video sequence. In the field of video coding, the terms "picture", "frame" or "image" may be used as synonyms. Video coding as used herein means video coding or video decoding. Video encoding is performed on the source side, and usually includes processing (eg, by compressing) the original video picture to reduce the amount of data required to represent the video picture, thereby storing and/or transmitting more efficiently. Video decoding is performed on the destination side and usually involves inverse processing relative to the encoder to reconstruct the video picture. The "encoding" of video pictures involved in the embodiments should be understood as referring to the "encoding" or "decoding" of video sequences. The combination of the encoding part and the decoding part is also called codec (encoding and decoding).

The video sequence includes a series of pictures, which are further divided into slices, and the slices are further divided into blocks. Video coding is performed in units of blocks. In some new video coding standards, the concept of blocks is further expanded. For example, in the H.264 standard, there is a macro block (MB, Macro), which can be further divided into multiple prediction blocks that can be used for predictive coding. In the HEVC standard, basic concepts such as coding unit (CU, Coding Unit), prediction unit (PU, Prediction Unit), and transformation unit (TU, Transform Unit) are used. A variety of block units are functionally divided and new The description is based on the tree structure. For example, the CU can be divided into smaller CUs according to the Quad Tree (QT, Quad Tree), and the smaller CU can continue to be divided to form a quad tree structure. The CU divides and encodes the encoded image Basic unit. There is a similar tree structure for PU and TU. PU can correspond to the prediction block and is the basic unit of predictive coding. The CU is further divided into multiple PUs according to the division mode. The TU can correspond to the transform block and is the basic unit for transforming the prediction residual. However, regardless of CU, PU or TU, they all belong to the concept of block (or image block) in essence.

For example, in HEVC, the CTU is split into multiple CUs by using a quadtree structure represented as a coding tree. A decision is made at the CU level whether to use inter-picture (temporal) or intra-picture (spatial) prediction to encode picture regions. Each CU can be further split into one, two, or four PUs according to the PU split type. The same prediction process is applied within a PU, and related information is transmitted to the decoder on the basis of the PU. After acquiring the residual block by applying a prediction process based on the PU split type, the CU may be divided into transform units (TU, Transform Unit) according to other quadtree structures similar to the coding tree used for the CU. In the latest development of video compression technology, quad-tree and binary-tree (QTBT, Quad-Tree and Binary Tree) partition frames are used to split the coding blocks. In the QTBT block structure, the CU may have a square or rectangular shape.

Here, for ease of description and understanding, the image block to be encoded in the current encoded image may be referred to as the current image block. For example, in encoding, it refers to the block currently being encoded; in decoding, it refers to the block currently being decoded. The decoded image block used to predict the current image block in the reference image is referred to as a reference block, that is, the reference block is a block that provides a reference signal for the current image block, where the reference signal represents a pixel value within the image block. The block in the reference image that provides the prediction signal for the current image block may be a prediction block, where the prediction signal represents a pixel value or a sample value or a sample signal within the prediction block. For example, after traversing multiple reference blocks, the best reference block is found. This best reference block will provide a prediction for the current image block. This block is called a prediction block.

In the case of lossless video coding, the original video picture can be reconstructed, that is, the reconstructed video picture has the same quality as the original video picture (assuming no transmission loss or other data loss during storage or transmission). In the case of lossy video encoding, further compression is performed by, for example, quantization to reduce the amount of data required to represent the video picture, but the decoder side cannot fully reconstruct the video picture, that is, the quality of the reconstructed video picture is better than the original video picture. The quality is lower or worse.

Several video coding standards of H.261 belong to "lossy hybrid video codec" (ie, combining spatial and temporal prediction in the sample domain with 2D transform coding for applying quantization in the transform domain). Each picture of a video sequence is usually divided into non-overlapping block sets, which are usually encoded at the block level. In other words, the encoder side usually processes the encoded video at the block (video block) level. For example, the prediction block is generated by spatial (intra-picture) prediction and temporal (inter-picture) prediction. From the current image block (current processing or The block to be processed) subtracts the prediction block to obtain the residual block, transforms the residual block in the transform domain and quantizes the residual block to reduce the amount of data to be transmitted (compressed), and the decoder side will reverse the inverse relative to the encoder The processing part is applied to the encoded or compressed block to reconstruct the current image block for representation. In addition, the encoder duplicates the decoder processing loop so that the encoder and decoder generate the same prediction (eg, intra prediction and inter prediction) and/or reconstruction for processing, ie encoding subsequent blocks.

The system architecture applied in the embodiments of the present application is described below. Referring to FIG. 1A, FIG. 1A exemplarily shows a schematic block diagram of a video encoding and decoding system 10 applied in an embodiment of the present application. As shown in FIG. 1A, the video encoding and decoding system 10 may include a source device 12 and a destination device 14, the source device 12 generates encoded video data, and therefore, the source device 12 may be referred to as a video encoding device. The destination device 14 may decode the encoded video data generated by the source device 12, and therefore, the destination device 14 may be referred to as a video decoding device. Various implementations of source device 12, destination device 14, or both may include one or more processors and memory coupled to the one or more processors. The memory may include, but is not limited to, RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store the desired program code in the form of instructions or data structures accessible by the computer, as described herein. Source device 12 and destination device 14 may include various devices, including desktop computers, mobile computing devices, notebook (eg, laptop) computers, tablet computers, set-top boxes, telephone handsets such as so-called "smart" phones, etc. Devices, televisions, cameras, display devices, digital media players, video game consoles, in-vehicle computers, wireless communication devices, or the like.

Although the source device 12 and the destination device 14 are depicted as separate devices in FIG. 1A, device embodiments may also include the functionality of both the source device 12 and the destination device 14 or both, ie, the source device 12 or The corresponding functionality and the destination device 14 or corresponding functionality. In such embodiments, the same hardware and/or software may be used, or separate hardware and/or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .

The communication connection between the source device 12 and the destination device 14 may be via a link 13, and the destination device 14 may receive the encoded video data from the source device 12 via the link 13. Link 13 may include one or more media or devices capable of moving encoded video data from source device 12 to destination device 14. In one example, link 13 may include one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in real time. In this example, the source device 12 may modulate the encoded video data according to a communication standard (eg, a wireless communication protocol), and may transmit the modulated video data to the destination device 14. The one or more communication media may include wireless and/or wired communication media, such as a radio frequency (RF, Radio Frequency) spectrum or one or more physical transmission lines. The one or more communication media may form part of a packet-based network, such as a local area network, a wide area network, or a global network (eg, the Internet). The one or more communication media may include routers, switches, base stations, or other devices that facilitate communication from source device 12 to destination device 14.

The source device 12 includes an encoder 20. Alternatively, the source device 12 may further include a picture source 16, a picture pre-processor 18, and a communication interface 22. In a specific implementation form, the encoder 20, the picture source 16, the picture pre-processor 18, and the communication interface 22 may be hardware components in the source device 12, or may be software programs in the source device 12. They are described as follows:

Picture source 16, which can include or can be any type of picture capture device, for example to capture real-world pictures, and/or any type of picture or comment (for screen content encoding, some text on the screen is also considered to be encoded Part of the picture or image) generation device, for example, a computer graphics processor for generating computer animation pictures, or for acquiring and/or providing real-world pictures, computer animation pictures (for example, screen content, virtual reality (VR, Virtual Reality (picture), any type of device, and/or any combination thereof (for example, Augmented Reality (AR) picture). The picture source 16 may be a camera for capturing pictures or a memory for storing pictures. The picture source 16 may also include any type of (internal or external) interface that stores previously captured or generated pictures and/or acquires or receives pictures. When the picture source 16 is a camera, the picture source 16 may be, for example, a local or integrated camera integrated in the source device; when the picture source 16 is a memory, the picture source 16 may be a local or integrated, for example, integrated in the source device Memory. When the picture source 16 includes an interface, the interface may be, for example, an external interface that receives pictures from an external video source. The external video source is, for example, an external picture capture device, such as a camera, an external memory, or an external picture generation device. The external picture generation device, for example It is an external computer graphics processor, computer or server. The interface may be any type of interface according to any proprietary or standardized interface protocol, such as a wired or wireless interface, an optical interface.

The picture can be regarded as a two-dimensional array or matrix of picture elements. The pixels in the array can also be called sampling points. The number of sampling points in the horizontal and vertical directions (or axes) of the array or picture defines the size and/or resolution of the picture. In order to represent colors, three color components are usually used, that is, a picture can be represented or contain three sampling arrays. For example, in the RBG format or color space, the picture includes corresponding red, green, and blue sampling arrays. However, in video coding, each pixel is usually expressed in a luminance/chrominance format or color space. For example, for a picture in YUV format, it includes the luminance component indicated by Y (sometimes also indicated by L) and the two indicated by U and V. Chroma components. The luma component Y represents luminance or gray-scale horizontal intensity (for example, both are the same in gray-scale pictures), and the two chroma components U and V represent chroma or color information components. Accordingly, the picture in the YUV format includes a luminance sampling array of luminance sampling values (Y), and two chrominance sampling arrays of chrominance values (U and V). RGB format pictures can be converted or transformed into YUV format and vice versa, this process is also called color transformation or conversion. If the picture is black and white, the picture may include only the brightness sampling array. In the embodiment of the present application, the picture transmitted from the picture source 16 to the picture processor may also be referred to as original picture data 17.

The picture pre-processor 18 is configured to receive the original picture data 17 and perform pre-processing on the original picture data 17 to obtain the pre-processed picture 19 or the pre-processed picture data 19. For example, the pre-processing performed by the picture pre-processor 18 may include trimming, color format conversion (eg, conversion from RGB format to YUV format), color grading, or denoising.

The encoder 20 (or video encoder 20) is used to receive the pre-processed picture data 19, and process the pre-processed picture data 19 in a related prediction mode (such as the prediction mode in various embodiments herein), thereby The encoded picture data 21 is provided (the structural details of the encoder 20 will be further described below based on FIG. 2 or FIG. 4 or FIG. 5). In some embodiments, the encoder 20 may be used to execute various embodiments described below to implement the application of the image block division method described in the present application on the encoding side.

The communication interface 22 can be used to receive the encoded picture data 21, and can transmit the encoded picture data 21 to the destination device 14 or any other device (such as a memory) via the link 13 for storage or direct reconstruction. The other device may be any device used for decoding or storage. The communication interface 22 may be used, for example, to encapsulate the encoded picture data 21 into a suitable format, such as a data packet, for transmission on the link 13.

The destination device 14 includes a decoder 30, and optionally, the destination device 14 may further include a communication interface 28, a post-picture processor 32, and a display device 34. They are described as follows:

The communication interface 28 may be used to receive the encoded picture data 21 from the source device 12 or any other source, such as a storage device, such as an encoded picture data storage device. The communication interface 28 can be used to transmit or receive the encoded picture data 21 through the link 13 between the source device 12 and the destination device 14 or through any type of network. The link 13 is, for example, a direct wired or wireless connection. A network of a category is, for example, a wired or wireless network or any combination thereof, or a private network and a public network of any category, or any combination thereof. The communication interface 28 may be used, for example, to decapsulate the data packet transmitted by the communication interface 22 to obtain the encoded picture data 21.

Both the communication interface 28 and the communication interface 22 may be configured as a one-way communication interface or a two-way communication interface, and may be used, for example, to send and receive messages to establish a connection, confirm and exchange any other communication link and/or for example encoded picture data Information about data transmission.

The decoder 30 (or referred to as the decoder 30) is used to receive the encoded picture data 21 and provide the decoded picture data 31 or the decoded picture 31 (hereinafter, the decoder 30 will be further described based on FIG. 3 or FIG. 4 or FIG. 5 Structural details). In some embodiments, the decoder 30 may be used to execute various embodiments described below to implement the application of the image block division method described in the present application on the decoding side.

The post-picture processor 32 is configured to perform post-processing on the decoded picture data 31 (also referred to as reconstructed picture data) to obtain post-processed picture data 33. The post-processing performed by the image post-processor 32 may include: color format conversion (for example, conversion from YUV format to RGB format), color adjustment, retouching or resampling, or any other processing, and may also be used to convert the post-processed image data 33transmitted to the display device 34.

The display device 34 is used to receive post-processed picture data 33 to display pictures to, for example, a user or a viewer. The display device 34 may be or may include any type of display for presenting reconstructed pictures, for example, an integrated or external display or monitor. For example, the display may include a liquid crystal display (LCD, Liquid) Display, an organic light emitting diode (OLED, Organic Light Emitting Diode) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (LCoS, Liquid On Crystal), Digital Light Processor (DLP, Digital Processor) or any other type of display.

Although the source device 12 and the destination device 14 are illustrated as separate devices in FIG. 1A, device embodiments may also include the functionality of the source device 12 and the destination device 14 or both, ie the source device 12 or corresponding functionality and destination device 14 or corresponding functionality. In such embodiments, the same hardware and/or software may be used, or separate hardware and/or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .

It is obvious to those skilled in the art based on the description that the existence and (accurate) division of the functionality of different units or the functionality of the source device 12 and/or the destination device 14 shown in FIG. 1A may vary according to actual devices and applications. Source device 12 and destination device 14 may include any of a variety of devices, including any type of handheld or stationary devices, such as notebook or laptop computers, mobile phones, smartphones, tablets or tablet computers, cameras, desktops Computers, set-top boxes, televisions, cameras, in-vehicle devices, display devices, digital media players, video game consoles, video streaming devices (such as content service servers or content distribution servers), broadcast receiver devices, broadcast transmitter devices And so on, and can not use or use any kind of operating system.

Both the encoder 20 and the decoder 30 can be implemented as any of various suitable circuits, for example, one or more microprocessors, digital signal processors (DSP, Digital Processor), application specific integrated circuits (ASIC, Application- Specific Integrated (Circuit), Field Programmable Gate Array (FPGA, Field-Programmable Gate Array), discrete logic, hardware, or any combination thereof. If the technology is partially implemented in software, the device may store the instructions of the software in a suitable non-transitory computer-readable storage medium, and may use one or more processors to execute the instructions in hardware to perform the technology of the present application . Any one of the foregoing (including hardware, software, a combination of hardware and software, etc.) may be regarded as one or more processors.

In some cases, the video encoding and decoding system 10 shown in FIG. 1A is only an example, and the technology of the present application may be applied to video encoding settings that do not necessarily include any data communication between encoding and decoding devices (eg, video encoding or video decoding). In other examples, data can be retrieved from local storage, streamed on the network, and so on. The video encoding device may encode the data and store the data to the memory, and/or the video decoding device may retrieve the data from the memory and decode the data. In some examples, encoding and decoding are performed by devices that do not communicate with each other but only encode data to and/or retrieve data from memory and decode the data.

Referring to FIG. 1B, FIG. 1B is an explanatory diagram of an example of a video coding system 40 including the encoder 20 of FIG. 2 and/or the decoder 30 of FIG. 3, according to an exemplary embodiment. The video decoding system 40 can implement a combination of various technologies in the embodiments of the present application. In the illustrated embodiment, the video decoding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and/or a video encoder/decoder implemented by the logic circuit 47 of the processing unit 46), an antenna 42 , One or more processors 43, one or more memories 44, and/or display devices 45.

As shown in FIG. 1B, the imaging device 41, the antenna 42, the processing unit 46, the logic circuit 47, the encoder 20, the decoder 30, the processor 43, the memory 44, and/or the display device 45 can communicate with each other. As discussed, although the video coding system 40 is shown with the encoder 20 and the decoder 30, in different examples, the video coding system 40 may include only the encoder 20 or only the decoder 30.

In some examples, antenna 42 may be used to transmit or receive an encoded bitstream of video data. Additionally, in some examples, the display device 45 may be used to present video data. In some examples, the logic circuit 47 may be implemented by the processing unit 46. The processing unit 46 may include ASIC logic, a graphics processor, a general-purpose processor, and the like. The video decoding system 40 may also include an optional processor 43, which may similarly include ASIC logic, a graphics processor, a general-purpose processor, and the like. In some examples, the logic circuit 47 may be implemented by hardware, such as dedicated hardware for video encoding, etc., and the processor 43 may be implemented by general-purpose software, an operating system, or the like. In addition, the memory 44 may be any type of memory, such as volatile memory (eg, static random access memory (SRAM, Static Random Access Memory), dynamic random access memory (DRAM, Dynamic Random Access Memory), etc.) or non-volatile Memory (for example, flash memory, etc.), etc. In a non-limiting example, the memory 44 may be implemented by cache memory. In some examples, the logic circuit 47 can access the memory 44 (eg, to implement an image buffer). In other examples, the logic circuit 47 and/or the processing unit 46 may include memory (eg, cache, etc.) for implementing image buffers and the like.

In some examples, the encoder 20 implemented by logic circuits may include an image buffer (eg, implemented by the processing unit 46 or the memory 44) and a graphics processing unit (eg, implemented by the processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include the encoder 20 implemented by a logic circuit 47 to implement the various modules discussed with reference to FIG. 2 and/or any other encoder system or subsystem described herein. Logic circuits can be used to perform the various operations discussed herein.

In some examples, decoder 30 may be implemented by logic circuit 47 in a similar manner to implement the various modules discussed with reference to decoder 30 of FIG. 3 and/or any other decoder systems or subsystems described herein. In some examples, the decoder 30 implemented by the logic circuit may include an image buffer (implemented by the processing unit 2820 or the memory 44) and a graphics processing unit (for example, implemented by the processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include a decoder 30 implemented by a logic circuit 47 to implement various modules discussed with reference to FIG. 3 and/or any other decoder system or subsystem described herein.

In some examples, antenna 42 may be used to receive an encoded bitstream of video data. As discussed, the encoded bitstream may include data related to encoded video frames, indicators, index values, mode selection data, etc. discussed herein, such as data related to encoded partitions (eg, transform coefficients or quantized transform coefficients , (As discussed) optional indicators, and/or data defining the code segmentation). The video coding system 40 may also include a decoder 30 coupled to the antenna 42 and used to decode the encoded bitstream. The display device 45 is used to present video frames.

It should be understood that in the example described with reference to the encoder 20 in the embodiment of the present application, the decoder 30 may be used to perform the reverse process. Regarding signaling syntax elements, the decoder 30 may be used to receive and parse such syntax elements and decode the relevant video data accordingly. In some examples, encoder 20 may entropy encode syntax elements into an encoded video bitstream. In such instances, decoder 30 may parse such syntax elements and decode the relevant video data accordingly.

It should be noted that the image block division method described in the embodiment of the present application is mainly used in the image segmentation process. This process exists in both the encoder 20 and the decoder 30. The encoder 20 and the decoder 30 in the embodiment of the present application may be For example, H.263, H.264, HEVV, MPEG-2, MPEG-4, VP8, VP9 and other video standard protocols or next-generation video standard protocols (such as H.266, etc.) corresponding codec/decoder.

Referring to FIG. 2, FIG. 2 shows a schematic/conceptual block diagram of an example of an encoder 20 for implementing an embodiment of the present application. In the example of FIG. 2, the encoder 20 includes a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a buffer 216, a loop filter Unit 220, decoded picture buffer (DPB, Decoded Picture Buffer) 230, prediction processing unit 260, and entropy encoding unit 270. The prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder based on a hybrid video codec.

For example, the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, the prediction processing unit 260, and the entropy encoding unit 270 form the forward signal path of the encoder 20, while, for example, the inverse quantization unit 210, the inverse transform processing unit 212, the heavy The construction unit 214, the buffer 216, the loop filter 220, the DPB 230, and the prediction processing unit 260 form the backward signal path of the encoder, where the backward signal path of the encoder corresponds to the signal path of the decoder (see FIG. 3). Decoder 30).

The encoder 20 receives a picture 201 or an image block 203 of the picture 201 through, for example, an input 202, for example, a picture in a picture sequence forming a video or a video sequence. The image block 203 may also be called a current picture block or a picture block to be encoded, and the picture 201 may be called a current picture or a picture to be encoded (especially when the current picture is distinguished from other pictures in video encoding, the other pictures are the same video sequence, for example That is, the previously encoded and/or decoded pictures in the video sequence of the current picture are also included).

An embodiment of the encoder 20 may include a division unit (not shown in FIG. 2) for dividing the picture 201 into a plurality of blocks such as image blocks 203, usually into a plurality of non-overlapping blocks. The segmentation unit can be used to use the same block size and corresponding grids that define the block size for all pictures in the video sequence, or to change the block size between pictures or subsets or picture groups, and divide each picture into The corresponding block.

In one example, the prediction processing unit 260 of the encoder 20 may be used to perform any combination of the above-mentioned segmentation techniques.

Like picture 201, image block 203 is also or can be regarded as a two-dimensional array or matrix of sampling points with sample values, although its size is smaller than picture 201. In other words, the image block 203 may include, for example, one sampling array (for example, the brightness array in the case of black and white picture 201) or three sampling arrays (for example, one brightness array and two chroma arrays in the case of color picture) or An array of any other number and/or category depending on the color format applied. The number of sampling points in the horizontal and vertical directions (or axes) of the image block 203 defines the size of the image block 203.

The encoder 20 shown in FIG. 2 is used to encode the picture 201 block by block, for example, to perform encoding and prediction on each image block 203.

The residual calculation unit 204 is used to calculate the residual block 205 based on the picture image block 203 and the prediction block 265 (other details of the prediction block 265 are provided below), for example, by subtracting the sample value of the picture image block 203 sample by sample (pixel by pixel) The sample values of the block 265 are depredicted to obtain the residual block 205 in the sample domain.

The transform processing unit 206 is used to apply transforms such as discrete cosine transform (DCT, Discrete Cosine Transform) or discrete sine transform (DST, Discrete Sine Transform) to the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain . The transform coefficient 207 may also be called a transform residual coefficient, and represents a residual block 205 in the transform domain.

The transform processing unit 206 may be used to apply integer approximations of DCT/DST, such as the transform specified by HEVC/H.265. Compared with the orthogonal DCT transform, this integer approximation is usually scaled by a factor. In order to maintain the norm of the residual block processed by the forward and inverse transform, an additional scaling factor is applied as part of the transform process. The scaling factor is usually selected based on certain constraints. For example, the scaling factor is a power of two used for the shift operation, the bit depth of the transform coefficient, the accuracy, and the trade-off between implementation cost, and so on. For example, a specific scaling factor can be specified for the inverse transform by the inverse transform processing unit 212 on the decoder 30 side (and corresponding inverse transform by the inverse transform processing unit 212 on the encoder 20 side), and accordingly, the encoder can be The 20 side specifies a corresponding scaling factor for the positive transform through the transform processing unit 206.

The quantization unit 208 is used to quantize the transform coefficient 207 by, for example, applying scalar quantization or vector quantization to obtain the quantized transform coefficient 209. The quantized transform coefficient 209 may also be referred to as a quantized residual coefficient 209. The quantization process can reduce the bit depth associated with some or all of the transform coefficients 207. For example, n-bit transform coefficients can be rounded down to m-bit transform coefficients during quantization, where n is greater than m. The degree of quantization can be modified by adjusting the quantization parameter (QP, Quantization). For example, for scalar quantization, different scales can be applied to achieve thinner or coarser quantization. A smaller quantization step size corresponds to a finer quantization, and a larger quantization step size corresponds to a coarser quantization. The appropriate quantization step size can be indicated by QP. For example, the quantization parameter may be an index of a predefined set of suitable quantization steps. For example, smaller quantization parameters may correspond to fine quantization (smaller quantization step size), larger quantization parameters may correspond to coarse quantization (larger quantization step size), and vice versa. The quantization may include dividing by the quantization step size and the corresponding quantization or inverse quantization performed by, for example, inverse quantization 210, or may include multiplying the quantization step size. Embodiments according to some standards such as HEVC may use quantization parameters to determine the quantization step size. In general, the quantization step size can be calculated based on the quantization parameter using fixed-point approximation that includes equations for division. Additional scaling factors can be introduced for quantization and inverse quantization to restore the norm of the residual block that may be modified due to the scale used in the fixed-point approximation of the equations for quantization step size and quantization parameter. In an example embodiment, the scale of inverse transform and inverse quantization may be combined. Alternatively, a custom quantization table can be used and signaled from the encoder to the decoder in the bitstream, for example. Quantization is a lossy operation, where the larger the quantization step, the greater the loss.

The inverse quantization unit 210 is used to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain the inverse quantization coefficients 211, for example, based on or using the same quantization step size as the quantization unit 208, apply the quantization scheme applied by the quantization unit 208 Inverse quantization scheme. The inverse quantized coefficient 211 may also be referred to as an inverse quantized residual coefficient 211, which corresponds to the transform coefficient 207, although the loss due to quantization is usually not the same as the transform coefficient.

The inverse transform processing unit 212 is used to apply the inverse transform of the transform applied by the transform processing unit 206, for example, inverse DCT or inverse DST, to obtain the inverse transform block 213 in the sample domain. The inverse transform block 213 may also be referred to as an inverse transform dequantized block 213 or an inverse transform residual block 213.

The reconstruction unit 214 (eg, summer 214) is used to add the inverse transform block 213 (ie, the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain, for example, The sample values of the reconstructed residual block 213 and the sample values of the prediction block 265 are added.

Optionally, a buffer unit 216 (or simply "buffer" 216), such as a line buffer 216, is used to buffer or store the reconstructed block 215 and corresponding sample values for, for example, intra prediction. In other embodiments, the encoder may be used to use the unfiltered reconstructed blocks and/or corresponding sample values stored in the buffer unit 216 for any type of estimation and/or prediction, such as intra prediction.

For example, an embodiment of the encoder 20 may be configured such that the buffer unit 216 is used not only to store the reconstructed block 215 for intra prediction 254, but also for the loop filter unit 220 (not shown in FIG. 2) Out), and/or, for example, causing the buffer unit 216 and the decoded picture buffer unit 230 to form a buffer. Other embodiments may be used to use the filtered block 221 and/or blocks or samples from the decoded picture buffer 230 (neither shown in FIG. 2) as an input or basis for intra prediction 254.

The loop filter unit 220 (or simply "loop filter" 220) is used to filter the reconstructed block 215 to obtain the filtered block 221, so as to smoothly perform pixel conversion or improve video quality. The loop filter unit 220 is intended to represent one or more loop filters, such as a deblocking filter, a sample adaptive offset (SAO) filter or other filters, such as a bilateral filter, a self-adapting filter Adaptive loop filter (ALF, Adaptive Loop Filter), or sharpening or smoothing filter, or collaborative filter. Although the loop filter unit 220 is shown as an in-loop filter in FIG. 2, in other configurations, the loop filter unit 220 may be implemented as a post-loop filter. The filtered block 221 may also be referred to as the filtered reconstructed block 221. The decoded picture buffer 230 may store the reconstructed encoding block after the loop filter unit 220 performs a filtering operation on the reconstructed encoding block.

Embodiments of the encoder 20 (correspondingly, the loop filter unit 220) may be used to output loop filter parameters (eg, sample adaptive offset information), for example, directly output or by the entropy encoding unit 270 or any other The entropy encoding unit outputs after entropy encoding, for example, so that the decoder 30 can receive and apply the same loop filter parameters for decoding.

The DPB 230 may be a reference picture memory that stores reference picture data for the encoder 20 to encode video data. DPB 230 can be formed by any of a variety of memory devices, such as DRAM (including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (resistive RAM, RRAM)), or other types Memory device. The DPB 230 and the buffer 216 may be provided by the same memory device or separate memory devices. In a certain example, DPB 230 is used to store filtered block 221. DPB230 can be further used to store other previous filtered blocks of the same current picture or different pictures such as previous reconstructed pictures, such as previously reconstructed and filtered block 221, and can provide a complete previous reconstructed ie. The decoded picture (and corresponding reference blocks and samples) and/or partially reconstructed current picture (and corresponding reference blocks and samples), for example, for inter prediction. In a certain example, if the reconstructed block 215 is reconstructed without in-loop filtering, the DPB 230 is used to store the reconstructed block 215.

The prediction processing unit 260, also known as the block prediction processing unit 260, is used to receive or acquire the image block 203 (current image block 203 of the current picture 201) and reconstructed picture data, such as the same (current) picture from the buffer 216 Reference samples and/or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and used to process such data for prediction, that is, to provide an inter prediction block 245 or The prediction block 265 of the intra prediction block 255.

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

An embodiment of the mode selection unit 262 may be used to select a prediction mode (for example, from those prediction modes supported by the prediction processing unit 260), which provides the best match or the minimum residual (the minimum residual means Better compression in transmission or storage), or provide minimum signaling overhead (minimum signaling overhead means better compression in transmission or storage), or consider or balance both at the same time. The mode selection unit 262 may be used to determine a prediction mode based on rate distortion optimization (RDO, Rate Distortion Optimization), that is, select a prediction mode that provides minimum bit rate distortion optimization, or select a prediction mode in which the related rate distortion at least meets the prediction mode selection criteria .

The prediction process performed by the example of the encoder 20 (for example, by the prediction processing unit 260) and the mode selection (for example, by the mode selection unit 262) will be explained in detail below.

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

The intra prediction mode set may include 35 different intra prediction modes, for example, non-directional modes such as DC (or mean) mode and planar mode, or directional modes as defined in H.265, or may include 67 Different intra prediction modes, for example, non-directional modes such as DC (or mean) mode and planar mode, or directional modes as defined in the developing H.266.

In a possible implementation, the set of inter prediction modes depends on the available reference pictures (ie, for example, the aforementioned at least partially decoded pictures stored in DBP 230) and other inter prediction parameters, for example, depending on whether the entire reference picture is used or only Use a part of the reference picture, for example a search window area surrounding the area of the current image block, to search for the best matching reference block, and/or for example depending on whether to apply inter-pixel interpolation such as half-pixel and/or quarter-pixel interpolation Interpolation, the set of inter prediction modes may include, for example, Advanced Motion Vector (AMVP, Advanced Vector) Prediction) mode and merge mode. In a specific implementation, the set of inter prediction modes may include an improved control point-based AMVP mode according to an embodiment of the present application, and an improved control point-based merge mode. In one example, the intra prediction unit 254 may be used to perform any combination of inter prediction techniques described below.

In addition to the above prediction modes, the embodiments of the present application may also apply skip mode and/or direct mode.

The prediction processing unit 260 may be further used to divide the image block 203 into smaller block partitions or sub-blocks, for example, iteratively using QT, BT, or Triple-Tree (TT), or any combination thereof, And for, for example, performing prediction for each of the block partitions or sub-blocks, where mode selection includes selecting a tree structure of the divided image block 203 and selecting a prediction mode applied to each of the block partitions or sub-blocks.

The inter prediction unit 244 may include a motion estimation (ME, Motion) unit (not shown in FIG. 2) and a motion compensation (MC, Motion Compensation) unit (not shown in FIG. 2). The motion estimation unit is used to receive or acquire a picture image block 203 (current picture image block 203 of the current picture 201) and a decoded picture 231, or at least one or more previously reconstructed blocks, for example, one or more other/different The reconstructed block of the previously decoded picture 231 is used for motion estimation. For example, the video sequence may include the current picture and the previously decoded picture 31, or in other words, the current picture and the previously decoded picture 31 may be part of the picture sequence forming the video sequence, or form the picture sequence.

For example, the encoder 20 may be used to select a reference block from multiple reference blocks of the same or different pictures in multiple other pictures, and provide a reference picture and/or provide a reference to a motion estimation unit (not shown in FIG. 2) The offset (spatial offset) between the position of the block (X, Y coordinates) and the position of the current image block is used as an inter prediction parameter. This offset is also called Motion Vector (MV, Motion Vector).

The motion compensation unit is used to acquire inter prediction parameters, and perform inter prediction based on or using inter prediction parameters to obtain inter prediction blocks 245. The motion compensation performed by the motion compensation unit (not shown in FIG. 2) may include extracting or generating a prediction block based on a motion/block vector determined by motion estimation (possibly performing interpolation of sub-pixel accuracy). Interpolation filtering can generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks that can be used to encode picture blocks. Once the motion vector for the PU of the current picture block is received, the motion compensation unit 246 may locate the prediction block pointed to by the motion vector in a reference picture list. Motion compensation unit 246 may also generate syntax elements associated with blocks and video slices for use by decoder 30 when decoding picture blocks of video slices.

Specifically, the above-mentioned inter prediction unit 244 may transmit a syntax element to the entropy encoding unit 270, where the syntax element includes inter prediction parameters (such as traversing multiple inter prediction modes to select an inter prediction mode used for current image block prediction Instructions). In a possible application scenario, if there is only one inter prediction mode, the inter prediction parameters may not be carried in the syntax element. In this case, the decoding terminal 30 may directly use the default prediction mode for decoding. It can be understood that the inter prediction unit 244 may be used to perform any combination of inter prediction techniques.

The intra prediction unit 254 is used to acquire, for example, a picture block 203 (current picture block) that receives the same picture and one or more previously reconstructed blocks, such as reconstructed neighboring blocks, for intra estimation. For example, the encoder 20 may be used to select an intra prediction mode from a plurality of (predetermined) intra prediction modes.

Embodiments of the encoder 20 may be used to select an intra prediction mode based on optimization criteria, for example, based on a minimum residual (eg, an intra prediction mode that provides the prediction block 255 most similar to the current picture block 203) or minimum rate distortion.

The intra prediction unit 254 is further used to determine the intra prediction block 255 based on the intra prediction parameters of the intra prediction mode as selected. In any case, after selecting the intra-prediction mode for the block, the intra-prediction unit 254 is also used to provide the intra-prediction parameters to the entropy encoding unit 270, that is, to provide an indication of the selected intra-prediction mode for the block Information. In one example, intra prediction unit 254 may be used to perform any combination of intra prediction techniques.

Specifically, the above-mentioned intra-prediction unit 254 may transmit a syntax element to the entropy encoding unit 270, where the syntax element includes intra-prediction parameters (such as traversing multiple intra-prediction modes to select an intra-prediction mode for prediction of the current image block Instructions). In a possible application scenario, if there is only one intra prediction mode, the intra prediction parameters may not be carried in the syntax element. In this case, the decoding terminal 30 may directly use the default prediction mode for decoding.

The entropy coding unit 270 is used to entropy coding algorithms or schemes (for example, variable length coding (VLC, Variable) Coding) schemes, context adaptive VLC (CAVLC, Context Adaptive VLC) schemes, arithmetic coding schemes, context adaptive binary arithmetic Coding (CABAC, Context Adaptive Binary Arithmetic Coding), grammar-based context-adaptive binary arithmetic coding (SBAC, Syntax-Based context-adaptive binary Arithmetic Coding), probability interval segmentation entropy (PIPE, Probability Interval Partitioning Entropy) coding or other entropy Coding method or technique) applied to a single or all of the quantized residual coefficients 209, inter prediction parameters, intra prediction parameters, and/or loop filter parameters (or not applied) to obtain the output 272 to For example, the encoded picture data 21 output in the form of an encoded bit stream 21. The encoded bitstream may be transmitted to the video decoder 30 or archived for later transmission or retrieval by the video decoder 30. The entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice being encoded.

Other structural variations of video encoder 20 may be used to encode video streams. For example, the non-transform based encoder 20 may directly quantize the residual signal without the transform processing unit 206 for certain blocks or frames. In another embodiment, the encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined into a single unit.

Specifically, in the embodiment of the present application, the encoder 20 may be used to implement the image block division method described in the embodiments below.

It should be understood that other structural changes of the video encoder 20 may be used to encode the video stream. For example, for some image blocks or image frames, the video encoder 20 can directly quantize the residual signal without processing by the transform processing unit 206, and accordingly, without processing by the inverse transform processing unit 212; or, for some For image blocks or image frames, the video encoder 20 does not generate residual data, and accordingly does not need to be processed by the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212; or, the video encoder 20 may convert The reconstructed image block is directly stored as a reference block without being processed by the filter 220; alternatively, the quantization unit 208 and the inverse quantization unit 210 in the video encoder 20 may be merged together. The loop filter 220 is optional, and in the case of lossless compression coding, the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212 are optional. It should be understood that the inter prediction unit 244 and the intra prediction unit 254 may be selectively enabled according to different application scenarios.

Referring to FIG. 3, FIG. 3 shows a schematic/conceptual block diagram of an example of a decoder 30 for implementing an embodiment of the present application. The video decoder 30 is used to receive encoded picture data (eg, encoded bitstream) 21, for example, encoded by the encoder 20, to obtain the decoded picture 231. During the decoding process, video decoder 30 receives video data from video encoder 20, such as an encoded video bitstream and associated syntax elements representing picture blocks of the encoded video slice.

In the example of FIG. 3, the decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (such as a summer 314), a buffer 316, a loop filter 320, a The decoded picture buffer 330 and the prediction processing unit 360. The prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362. In some examples, video decoder 30 may perform a decoding pass that is generally inverse to the encoding pass described with reference to video encoder 20 of FIG. 2.

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

The inverse quantization unit 310 may be functionally the same as the inverse quantization unit 110, the inverse transform processing unit 312 may be functionally the same as the inverse transform processing unit 212, the reconstruction unit 314 may be functionally the same as the reconstruction unit 214, and the buffer 316 may be functionally Like the buffer 216, the loop filter 320 may be functionally the same as the loop filter 220, and the decoded picture buffer 330 may be functionally the same as the decoded picture buffer 230.

The prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354, wherein the inter prediction unit 344 may be similar in function to the inter prediction unit 244, and the intra prediction unit 354 may be similar in function to the intra prediction unit 254 . The prediction processing unit 360 is generally used to perform block prediction and/or obtain the prediction block 365 from the encoded data 21, and receive or obtain prediction-related parameters and/or information about the entropy decoding unit 304 (explicitly or implicitly). Information about the selected prediction mode.

When the video slice is encoded as an intra-coded (I) slice, the intra prediction unit 354 of the prediction processing unit 360 is used to signal-based the intra prediction mode and the previous decoded block from the current frame or picture. Data to generate a prediction block 365 for the picture block of the current video slice. When the video frame is encoded as an inter-coded (ie, B or P) slice, the inter prediction unit 344 (eg, motion compensation unit) of the prediction processing unit 360 is used for the motion vector-based and received from the entropy decoding unit 304 Other syntax elements generate a prediction block 365 for the video block of the current video slice. For inter prediction, a prediction block may be generated from a reference picture in a reference picture list. The video decoder 30 may construct the reference frame lists: list 0 and list 1 based on the reference pictures stored in the DPB 330 using default construction techniques.

The prediction processing unit 360 is used to determine the prediction information for the video block of the current video slice by parsing the motion vector and other syntax elements, and use the prediction information to generate the prediction block for the current video block being decoded. In an example of the present application, the prediction processing unit 360 uses some received syntax elements to determine the prediction mode (eg, intra or inter prediction) of the video block used to encode the video slice, and the inter prediction slice type ( For example, B slice, P slice, or GPB slice), construction information of one or more of the reference picture lists for slices, motion vectors for each inter-coded video block for slices, The inter prediction status and other information of each inter-coded video block of the slice to decode the video block of the current video slice. In another example of the present application, the syntax elements received by the video decoder 30 from the bitstream include receiving an adaptive parameter set (APS, Adaptive Parameter Set), sequence parameter set (SPS, Sequence Parameter Set), and picture parameter set (PPS , Picture, Parameter, or one or more of the syntax elements in the stripe header.

The inverse quantization unit 310 may be used to inverse quantize (ie, inverse quantize) the quantized transform coefficients provided in the bitstream and decoded by the entropy decoding unit 304. The inverse quantization process may include using the quantization parameters calculated by the video encoder 20 for each video block in the video slice to determine the degree of quantization that should be applied and also determine the degree of inverse quantization that should be applied.

The inverse transform processing unit 312 is used to apply an inverse transform (eg, inverse DCT, inverse integer transform, or conceptually similar inverse transform process) to the transform coefficients, so as to generate a residual block in the pixel domain.

The reconstruction unit 314 (eg, summer 314) is used to add the inverse transform block 313 (ie, the reconstructed residual block 313) to the prediction block 365 to obtain the reconstructed block 315 in the sample domain, for example by The sample values of the reconstructed residual block 313 are added to the sample values of the prediction block 365.

The loop filter unit 320 (during the encoding loop or after the encoding loop) is used to filter the reconstructed block 315 to obtain the filtered block 321 to smoothly perform pixel conversion or improve video quality. In one example, the loop filter unit 320 may be used to perform any combination of filtering techniques described below. The loop filter unit 320 is intended to represent one or more loop filters, such as deblocking filters, SAO filters, or other filters, such as bilateral filters, ALF, or sharpening or smoothing filters, or collaborative filtering Device. Although the loop filter unit 320 is shown as an in-loop filter in FIG. 3, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.

The decoded video block 321 in a given frame or picture is then stored in a decoded picture buffer 330 that stores reference pictures for subsequent motion compensation.

The decoder 30 is used, for example, to output the decoded picture 31 through the output 332 for presentation to the user or for the user to view.

Other variations of video decoder 30 may be used to decode the compressed bitstream. For example, the decoder 30 may generate the output video stream without the loop filter unit 320. For example, the non-transform based decoder 30 may directly inversely quantize the residual signal without the inverse transform processing unit 312 for certain blocks or frames. In another embodiment, the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined into a single unit.

Specifically, in the embodiment of the present application, the decoder 30 is used to implement the image block division method described in the embodiment below.

It should be understood that other structural variations of video decoder 30 may be used to decode the encoded video bitstream. For example, the video decoder 30 may generate an output video stream without processing by the filter 320; or, for certain image blocks or image frames, the entropy decoding unit 304 of the video decoder 30 does not decode the quantized coefficients, and accordingly does not It needs to be processed by the inverse quantization unit 310 and the inverse transform processing unit 312. The loop filter 320 is optional; and in the case of lossless compression, the inverse quantization unit 310 and the inverse transform processing unit 312 are optional. It should be understood that, according to different application scenarios, the inter prediction unit and the intra prediction unit may be selectively enabled.

It should be understood that in the encoder 20 and the decoder 30 of the present application, the processing results for a certain link can be further processed and output to the next link, for example, in interpolation filtering, motion vector derivation or loop filtering, etc. After the link, the results of the corresponding link are further clipped or shift shifted.

For example, the motion vector of the control point of the current image block derived from the motion vector of the adjacent affine coding block, or the motion vector of the sub-block of the current image block derived, may be further processed, and this application does not limited. For example, the value range of the motion vector is constrained to be within a certain bit width. Assuming that the allowed bit width of the motion vector is bitDepth, the range of the motion vector is -2＾(bitDepth-1)～2＾(bitDepth-1)-1, where the “＾” symbol represents the power. If bitDepth is 16, the value range is -32768~32767. If bitDepth is 18, the value ranges from -131072 to 131071. For another example, the value of the motion vector (such as the motion vectors MV of four 4x4 sub-blocks in an 8x8 image block) is constrained so that the maximum difference between the integer parts of the four 4×4 sub-blocks MV No more than N pixels, for example no more than one pixel.

It can be constrained in the following two ways to make it within a certain bit width:

Method 1: Remove the high bits of the motion vector overflow:

ux=(vx+2 ^bitDepth )%2 ^bitDepth

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

uy=(vy+2 ^bitDepth )%2 ^bitDepth

vy=(uy>=2 ^bitDepth-1 )? (uy-2 ^bitDept ):uy

Where vx is the horizontal component of the motion vector of the image block or the sub-block of the image block, vy is the vertical component of the motion vector of the image block or the sub-block of the image block, ux and uy are intermediate values; bitDepth represents the bit width.

For example, the value of vx is -32769, and the value obtained by the above formula is 32767. Because in the computer, the value is stored in the form of two's complement, the complement of -32769 is 1,0111,1111,1111,1111 (17 bits), the computer handles the overflow as discarding the high bit, then the value of vx If it is 0111,1111,1111,1111, it is 32767, which is consistent with the result obtained by formula processing.

Method 2: Clipping the motion vector, as shown in the following formula:

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

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

Where vx is the horizontal component of the motion vector of the image block or the sub-block of the image block, and vy is the vertical component of the motion vector of the image block or the sub-block of the image block; where x, y, and z correspond to the MV clamp, respectively The three input values of the Clip3 in the bit process. The definition of Clip3 is that the value of z is clamped to the interval [x, y]:

Referring to FIG. 4, FIG. 4 is a schematic structural diagram of a video decoding device 400 (for example, a video encoding device 400 or a video decoding device 400) provided by an embodiment of the present application. The video coding apparatus 400 is suitable for implementing the embodiments described herein. In one embodiment, the video coding device 400 may be a video decoder (eg, decoder 30 of FIG. 1A) or a video encoder (eg, encoder 20 of FIG. 1A). In another embodiment, the video decoding device 400 may be one or more components in the decoder 30 of FIG. 1A or the encoder 20 of FIG. 1A described above.

The video decoding device 400 includes: an inlet port 410 for receiving data and a receiving unit (Rx) 420, a processor for processing data, a logic unit or a central processing unit (CPU) 430, and a transmitter unit for transmitting data (Tx) 440 and exit port 450, and a memory 460 for storing data. The video decoding device 400 may further include a photoelectric conversion component and an electro-optical (EO) component coupled to the inlet port 410, the receiver unit 420, the transmitter unit 440, and the outlet port 450 for the outlet or inlet of the optical signal or the electrical signal.

The processor 430 is implemented by hardware and software. The processor 430 may be implemented as one or more CPU chips, cores (eg, multi-core processors), FPGA, ASIC, and DSP. The processor 430 communicates with the inlet port 410, the receiver unit 420, the transmitter unit 440, the outlet port 450, and the memory 460. The processor 430 includes a decoding module 470 (for example, an encoding module 470 or a decoding module 470). The encoding/decoding module 470 implements the embodiments disclosed herein to implement the chroma block prediction method provided by the embodiments of the present application. For example, the encoding/decoding module 470 implements, processes, or provides various encoding operations. Therefore, the encoding/decoding module 470 provides a substantial improvement to the function of the video decoding device 400 and affects the conversion of the video decoding device 400 to different states. Alternatively, the encoding/decoding module 470 is implemented with instructions stored in the memory 460 and executed by the processor 430.

The memory 460 includes one or more magnetic disks, tape drives, and solid-state hard disks, and can be used as an overflow data storage device for storing programs when these programs are selectively executed, as well as instructions and data read during program execution. The memory 460 may be volatile and/or non-volatile, and may be read only memory (ROM), random access memory (RAM), random access memory (TCAM, Ternary Content-Addressable Memory) and/or static Random Access Memory (SRAM).

Referring to FIG. 5, FIG. 5 is a simplified block diagram of an apparatus 500 that can be used as either or both of the source device 12 and the destination device 14 in FIG. 1A according to an exemplary embodiment. The device 500 can implement the technology of the present application. In other words, FIG. 5 is a schematic block diagram of an implementation manner of an encoding device or a decoding device (referred to simply as a decoding device 500) according to an embodiment of the present application. The decoding device 500 may include a processor 510, a memory 530, and a bus system 550. The processor and the memory are connected through a bus system, the memory is used to store instructions, and the processor is used to execute the instructions stored in the memory. The memory of the decoding device stores the program code, and the processor can call the program code stored in the memory to perform various video encoding or decoding methods described in this application, especially various new image block division methods. In order to avoid repetition, they are not described in detail here.

In the embodiment of the present application, the processor 510 may be a central processing unit (CPU, Central Processing Unit), and the processor 510 may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs) , Off-the-shelf programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 530 may include a read only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device may also be used as the memory 530. The memory 530 may include code and data 531 accessed by the processor 510 using the bus 550. The memory 530 may further include an operating system 533 and an application program 535 including at least one program that allows the processor 510 to perform the video encoding or decoding method described in the present application (in particular, the image block division method described in the present application). For example, the application program 535 may include applications 1 to N, which further include a video encoding or decoding application (referred to as a video coding application for short) that performs the video encoding or decoding method described in this application.

In addition to the data bus, the bus system 550 may also include a power bus, a control bus, and a status signal bus. However, for clarity, various buses are marked as the bus system 550 in the figure.

Optionally, the decoding device 500 may also include one or more output devices, such as a display 570. In one example, the display 570 may be a tactile display that merges the display with a tactile unit that operably senses touch input. The display 570 may be connected to the processor 510 via the bus 550.

The scheme of the embodiment of the present application is explained in detail below:

The video coding standard divides a frame of images into non-overlapping coding tree units (CTU). The size of a CTU can be set to 64×64 (the size of the CTU can also be set to other values, such as the CTU size increased to 128×128 Or 256×256, etc.). A 64×64 CTU contains a rectangular pixel lattice of 64 pixels in each column and each pixel contains a luminance component or/and a chrominance component. Next, further divide in CTU units. At this time, you can use BT-based division methods, such as horizontal binary tree (HBT, Horizontal Binary Tree), vertical binary tree (VBT, Vertical Binary Tree) division method; you can also Use the division method based on Quad Tree (QT, Quad); You can also use the division method based on Triple-Tree (TT, Triple-Tree); You can also use the division method of Extended Quad Tree (EQT, Extended Tree) , Such as the division method based on the horizontally expanded quadtree (HEQT, Horizontal Extended Tree), and the vertically expanded quadtree (VEQT, Vertical Extended Tree).

FIG. 6 is a schematic diagram of the BT, QT, and EQT division modes in the embodiment of the present application. With reference to FIG. 6, the following uses the decoding side to divide an image block as an example to describe the foregoing several division modes.

A frame of image can be divided into multiple non-overlapping CTUs. For a CTU, the CTU can be used as the root node of the quadtree, and the CTU is recursively divided into several leaf nodes according to the division method of the quadtree. A node corresponds to an image area, that is, an image block. If the node is no longer divided, the node is called a leaf node, and the image area corresponding to it forms a CU; if the node continues to divide, the image corresponding to the node The area is divided into four sub-areas of the same size as shown in Figure 6(a) (its width and height are each half of the divided area), each sub-area corresponds to a sub-node, and it is necessary to determine whether these sub-nodes are Will continue to divide. Whether a node is divided is indicated by the split flag bit split_cu_flag corresponding to this node in the code stream. The quad-tree level (qtDepth) of the root node is 0, and the quad-tree level of the child node is the quad-tree level of the parent node plus one. For simplicity, the size and shape of the node in the following refers to the size and shape of the image area corresponding to the node.

More specifically, for a 64×64 CTU node (the quadtree level is 0), according to its corresponding split_cu_flag, you can choose not to divide into 1 64×64 CU, or choose to divide into 4 32×32 Node (quadtree level is 1). Each of the four 32×32 nodes can choose to continue or not to divide according to its corresponding split_cu_flag; if a 32×32 node continues to divide, four 16×16 nodes (four The fork tree level is 2). By analogy, until all nodes are no longer divided, such a CTU is divided into a group of CU. The minimum size of the CU is identified in the SPS, for example, 8×8 is the smallest CU. In the above recursive division process, if the size of a node is equal to the minimum CU side length (minCUSize), this node defaults to no division, and it does not need to include its split_cu_flag in the code stream.

In the process of formulating the latest AVS3, AVS3 added BT division and EQT division on the basis of QT division.

Among them, the BT division method is to divide a node into two sub-nodes. There are two specific BT division methods: 1) HBT: divide the area corresponding to the node into two sub-areas of the same size (that is, the width is unchanged) , The height becomes half of the area before division), each sub-area corresponds to a child node; as shown in Figure 6(b); 2) VBT: divide the area corresponding to the node into two areas of the same size on the left and right ( That is, the height remains unchanged, and the width becomes half of the area before division), as shown in Fig. 6(c).

The EQT division method is to divide a node into 4 child nodes. There are two specific EQT division methods:

1) HEQT: the area corresponding to the node is divided into three sub-areas of upper, middle and lower, and the middle sub-area is divided into two sub-areas of middle left and right, each sub-area corresponds to a sub-node, among which The heights of the center left, center right, and bottom four subregions are 1/4, 1/2, 1/2, 1/4 of the node height, and the width of the center left and center right are 1/2, 1/2 of the node height , As shown in Fig. 6(d); 2) VEQT: divide the area corresponding to the node into three areas of left, center and right, and vertically divide the middle sub-area into two sub-areas of upper middle and lower middle, Each area corresponds to a node, where the widths of the four sub-areas of left, middle upper, middle lower, and right are 1/4, 1/2, 1/2, 1/4 of the node height, and the width of the middle upper and lower middle It is 1/2 and 1/2 of the node height, as shown in Figure 6(e).

In AVS3, QT concatenated BT/EQT is also used, that is, the nodes on the first-level coding tree can only be divided into child nodes using QT, and the leaf nodes of the first-level coding tree are the root nodes of the second-level coding tree The nodes on the second-level coding tree can be divided into child nodes using one of the BT or EQT division methods; the leaf nodes of the second-level coding tree are coding units. It should be noted that when a leaf node is divided into BT or EQT, its leaf nodes can only use BT or EQT, but not QT.

The multi-purpose video coding test model (VTM, Versatile Video Coding Test Model) reference software adds BT division method and TT division method on the basis of QT division. Among them, VTM is a new codec reference software developed by JVET.

The TT division method is to divide a node into three sub-nodes. There are two specific TT division methods: 1) Horizontal TT (HTT, Horizontal TT): the area corresponding to the node is divided into three sub-areas of upper, middle and lower, each Each sub-region corresponds to a sub-node, where the heights of the upper, middle, and lower regions are 1/4, 1/2, and 1/4 of the node height; 2) Vertical TT (VTT, Vertical TT): the node The corresponding area is divided into three sub-regions: left, center, and right. Each sub-region corresponds to a child node. The widths of the left, center, and right regions are 1/4, 1/2, and 1/4 of the node height. .

VTM uses the division method of QT cascaded BT/TT, referred to as QT-MTT (Quad Tree Plus plus Multi-Type Tree) division method. More specifically, the CTU generates QT child nodes through QT division. The child nodes in QT can be further divided into four QT child nodes using QT division, or no longer generate a QT leaf node. Then, the QT leaf node is used as the root node of the MTT, and one of the four division methods of HBT, VBT, HTT, and VTT is used to divide into child nodes, or no longer divided into an MTT leaf node. The leaf node of MTT corresponds to a CU.

For example, FIG. 7 is a schematic diagram of a division method based on QT-MTT in an embodiment of the present application. As shown in FIG. 7, each endpoint in the right diagram of FIG. 7 represents a node, and a node is connected with 4 lines Indicates QT division, 2 lines connected to one node represent BT division, and 3 lines connected to one node represent TT division. Among them, the solid line represents the QT division, the dashed line represents the first layer division of the multi-type division (MTT, Multi-Type Tree), and the dot-and-dash line represents the second layer division of the MTT. a to p are 16 MTT leaf nodes, and each MTT leaf node corresponds to a CU. A CTU is divided into 16 CUs such as a to p based on the QT-MTT division method according to the division method of the right diagram in FIG. 7 to obtain the CU division diagram shown in the left diagram of FIG. 7.

In the QT-MTT division method, each CU has a QT depth (QT depth), also called QT depth, and an MTT depth (MTT depth), also called MTT depth. The QT level represents the QT level of the QT leaf node to which the CU belongs, and the MTT level represents the MTT level of the MTT leaf node to which the CU belongs. The QT level of the root node of the coding tree is 0, and the MTT level is 0. If a node on the coding tree uses QT division, the QT level of the divided child node is the QT level of the node plus 1, the MTT level remains unchanged; similarly, if a node on the coding tree uses MTT division (ie BT or TT One of the divisions), the MTT level of the child node obtained by the division is the MTT level of the node plus 1, and the QT level remains unchanged. For example, in Figure 7, the QT level of a, b, c, d, e, f, g, i, j is 1, and the MTT level is 2; the QT level of h is 1, and the MTT level is 1; n, o, p The QT level is 2, and the MTT level is 0; the QT level of l and m is 2, and the MTTT level is 1. If the CTU is divided into only one CU, the QT level of this CU is 0 and the MTT level is 0.

It should be noted that, in the above coding tree generated by multiple division methods, one node corresponds to one image block, and the image block corresponding to one leaf node is CU.

When dividing an image block during the encoding of a video sequence, to determine the division method of an image block, it is necessary to first calculate the rate-distortion cost corresponding to each of the above-mentioned division methods, and compare the rate-distortion costs to determine the The optimal division method of image blocks; when dividing the image blocks during the decoding of the video sequence, it is necessary to continuously analyze the division method of each image block from the code stream, and the image blocks divided according to the resolved division method can be correct decoding. It can be seen that the computational complexity of video sequence encoding and decoding is too high.

In order to solve the above problems, the embodiments of the present application provide an image block division method, which can be applied to the encoding process of the encoder or the decoding process of the decoder.

Example one of this application:

FIG. 8 is a schematic diagram of an implementation process of an image block division method in an embodiment of the present application. As shown in FIG. 8, the image block division method includes:.

S801: Obtain the block information of the current image block in the current image;

In practical applications, the above-mentioned current image block is an image block divided by the current image, corresponding to a node on the coding tree of the current image. The current image block may be a CTU of the current image, or may be a CTU as the root node The sub-block obtained by division may also be a sub-block of the next level obtained by dividing a sub-block of one level as a root node.

The block information of the current image block may include the size information of the current image block, such as the width and height of the current image block, and may also include the coordinates of the pixels in the current image block. Here, the coordinates of the pixels are relative to the upper left vertex of the current image. Of course, the block information can be the image-related information corresponding to the current image block. These block information can be derived from the current image, such as the current image during the process of image block division, by the size of the current image. The information is derived from, or parsed from the code stream.

Then, if the decoding end implements S801, after receiving the code stream from the encoding end, the decoding end parses the code stream to obtain the block information of the corresponding current image block therefrom. If the encoding end implements S801, the encoding end may obtain the block information of the current image block from the image information of the current image, for example, the coordinates of the pixel points in the current image block according to the coordinates of the pixel points in the current image, Then, the width and/or height of the current image block are calculated.

S802: According to the block information, determine whether the current image block exceeds the boundary of the current image;

First, it should be noted that the above-mentioned current image block beyond the current image boundary does not mean that there are still pixel values in the current image block beyond the image boundary, but it refers to the current image block in a certain direction or two directions The maximum coordinate value exceeds the coordinate value of the image boundary along the same direction.

FIG. 9 is a schematic diagram of the current image block exceeding the current image boundary in the embodiment of the present application. As shown in FIG. 9, the dotted line indicates that the current image block may exceed the boundary of the current image, where the positive direction of the horizontal axis is to the right , The positive direction of the vertical axis is downward, the current image block 91 represents the image block beyond the right boundary of the current image 90, the current image block 92 represents the image block beyond the lower boundary of the current image 90, and the current image block 93 represents the image block beyond the current image 90 The image block at the lower right boundary (that is, the current image block exceeds the right and lower boundaries of the current image).

In some possible implementation manners, the decoding side may determine whether the current image block exceeds the boundary of the current image according to the obtained block information, such as the coordinates of pixels in the current image block. Then, S802 may include: obtaining the coordinates (x, y) of a pixel in the current image block according to the block information; determining whether the coordinates (x, y) of the pixel satisfy the preset condition, if the coordinates of the pixel (x , Y) meets the first preset condition, it means that the pixel exceeds the right boundary of the current image, if the pixel coordinates (x, y) meet the second preset condition, it means that the pixel exceeds the lower boundary of the current image, if the pixel The coordinates (x, y) satisfy the third preset condition, which indicates that the pixel point exceeds the right boundary of the current image and exceeds the lower boundary of the current image.

Here, the above pixel points are used to represent the current image block, and specific pixel points in the current image block can be selected to represent the current image block, such as the pixel points of each vertex of the current image block, such as the pixel point of the upper left vertex, the upper right The pixel point of the vertex, the pixel point of the lower left vertex or the pixel point of the lower right vertex, of course, you can also select the pixel point of the center position of the current image block. By comparing the coordinates of these pixel points with the coordinates of the boundary of the current image, it can be determined whether the current image block exceeds the boundary of the current image. In order to further improve the accuracy, any pixel in the current image block can also be selected and used to determine whether the current image block exceeds the boundary of the current image.

For example, the coordinates (x, y) of the pixel points are the coordinates of the pixel position of the upper left vertex in the current image block relative to the pixel position of the upper left vertex of the current image; accordingly, the first preset condition may be: a pixel The coordinates (x, y) satisfy x+cW>picW, and y+cH≤picH; the above second preset condition may be: the coordinates (x, y) of the pixel satisfy x+cW≤picW, and y+cH >picH; the above third preset condition may be: the coordinates (x, y) of the pixel satisfy x+cW>picW, and y+cH>picH; where cW is the width of the current image block and cH is the current image block Height, picW is the width of the current image, picH is the height of the current image.

It can be seen that after S801, it is determined whether the width and height of the current image block satisfy the first preset condition, the second preset condition, and the third preset condition. If any of the above three conditions are met, the current status can be confirmed. The image block exceeds the boundary of the current image, and it is determined according to the preset conditions satisfied by the block information whether the current image block specifically exceeds the right boundary or the lower boundary of the current image, or both the right boundary and the lower boundary.

Of course, other conditions may also be used to determine whether the current image block exceeds the boundary of the current image, which is not specifically limited in this embodiment of the present application.

S803: If the current image block exceeds the boundary of the current image, determine the mandatory division method for the current image block;

Here, after judging that the current image block exceeds the right boundary and/or the lower boundary of the current image, the forced division method is determined for the current image block according to the specific exceeding situation. The forced division method refers to that the division method of the current image block does not need to be obtained by parsing the code stream, and the current image block is directly divided using the forced division method.

In some possible implementation manners, when S802 determines that the current image block exceeds the right or lower boundary of the current image, S803 may include: comparing the size information of the current image block with a preset threshold to determine a correspondence for the current image block The forced division mode of the image, that is, the size information of the current image block is compared with a preset threshold, and the corresponding forced division mode is determined for the current image block according to the comparison result.

In the embodiment of the present application, the above-mentioned preset threshold may be set in the video encoder or video decoder, or a high-level syntax element (eg, sequence parameter set (SPS, Sequence Parameter Set), image) in the code stream from the decoding end The parameter set (PPS, Picture, Set) or slice header (parse header) is obtained by parsing. The value of the preset threshold may be different according to actual needs, and the embodiment of the present application does not specifically limit it.

For example, when the current image block exceeds the right or lower boundary of the current image, S803 may and is not limited to be implemented according to the following method:

method one:

When the current image block exceeds the right boundary of the current image, if the width of the current image block is equal to the threshold K (that is, the first preset threshold), and the height of the current image block is greater than the threshold K, it can be determined that the current image block is forced to comply with HBT The division method is divided, that is to say, the mandatory division method of the current image block is the HBT division method; otherwise, if the width of the current image block is not equal to the threshold K, and the height of the current image block is less than or equal to the threshold K, you can determine the current The image blocks are forcibly divided according to the VBT division mode, that is to say, the forced division mode of the current image block is determined as the VBT division mode. At this time, the threshold K is a positive integer;

When the current image block exceeds the lower boundary of the current image, if the width of the current image block is greater than the threshold K, and the height of the current image block is equal to the threshold K, it can be determined that the current image block is forcibly divided according to the VBT division method, that is to say determined The forced division method of the current image block is the division method of VBT; otherwise, if the width of the current image block is less than or equal to the threshold K, and the height of the current image block is not equal to the threshold K, it can be determined that the current image block is forcedly divided according to HBT Division, that is to say, the forced division mode of the current image block is the division mode of HBT.

The above threshold K (that is, the first preset threshold) can be set in the video encoder or video decoder (for example, set to 64), or the video decoder can extract high-level syntax elements (for example, SPS, PPS or slice header).

Method Two:

When the current image block exceeds the right boundary of the current image, if the width of the current image block is equal to the threshold M (ie, the second preset threshold), and the height of the current image block is equal to the threshold L (ie, the third preset threshold), then It is determined that the current image block is forcibly divided according to the HBT division method, that is to say, the forced division method of the current image block is the HBT division method; otherwise, if the width of the current image block is not equal to the threshold M and the height of the current image block is not equal to Threshold L, it can be determined that the current image block is forcibly divided according to the VBT division mode, that is to say, the forced division mode of the current image block is the VBT division mode; here, the threshold M is smaller than the threshold L.

When the current image block exceeds the lower boundary of the current image, if the height of the current image block is equal to the threshold M and the width of the current image block is equal to the threshold L, it can be determined that the current image block is forcibly divided according to the VBT division method, that is to say determined The forced division of the current image block is the division of VBT; otherwise, if the height of the current image block is not equal to the threshold M and the width of the current image block is not equal to the threshold L, it can be determined that the current image block is forcibly divided according to the HBT division method That is to say, the forced division method of the current image block is determined as the HBT division method.

Both the threshold M and the threshold L can be set in the video encoder or video decoder, or can be parsed by the decoding end from high-level syntax elements (for example, SPS, PPS, or slice header) in the code stream. In the embodiment of the present application, the threshold M may be an integer greater than or equal to 32, for example, the threshold M is 64 and the threshold L is 128; the threshold M may be 32 and the threshold L is 128. Of course, the values of the threshold value M and the threshold value L may have other situations, as long as the condition that the threshold value M is smaller than the threshold value L can be satisfied, and the embodiments of the present application are not specifically limited.

In the embodiment of the present application, except for the case where the current image block exceeds the right or lower boundary of the current image, when the current image block exceeds both the right boundary of the current image and the lower boundary of the current image, the current image block can be determined It is forcibly divided according to the QT division mode, that is to say, the forced division mode of the current image block is determined as the QT division mode.

In the specific implementation process, when the current image block exceeds the right border and/or the lower border of the current image, other methods may also be used to determine the mandatory division method for the current image block, which can be set by those skilled in the art. The embodiment does not specifically limit this.

The values of the threshold K, the threshold M and the threshold L can be set according to the needs of actual image division, and are not limited to the above examples.

The above-mentioned mandatory division method for the current image block can be and is not limited to one or more of the cascade of HBT, VBT, QT, HEQT and VEQT. Among them, HBT and VBT belong to the BT division method Specific application, HEQT and VEQT belong to the specific application of EQT division. For example, in the AVS3 standard, QT concatenated BT/EQT is used, that is, the nodes on the first level coding tree can only be divided into child nodes using QT, and the child nodes of the first level coding tree are the second level coding tree The root node of the second level coding tree can be divided into child nodes using one of the BT or EQT division methods. It should be noted that when a child node uses BT or EQT division, its child nodes can only use BT or EQT division, but not QT division.

S804: Divide the current image block according to the forced division method.

Here, after the forced division mode of the current image block is determined through S803, the current image block is forcedly divided according to the determined forced division mode to obtain multiple sub-blocks.

Next, the decoding end can perform S801 to S804 for each of these sub-blocks, and so on, until all the sub-blocks cannot be further divided, at this time, the decoding end can obtain the leaf nodes under the current image block, The image area corresponding to these leaf nodes is the CU. Then, the decoding end parses and obtains the syntax elements corresponding to each CU from the code stream, obtains the prediction information and residual information of each CU and each sub-region, and can perform inter-frame on each sub-region according to the corresponding prediction information of each sub-region The prediction process or the intra prediction process obtains the inter prediction block or the intra prediction block of each sub-region. According to the residual information of each sub-region, the transform coefficients are subjected to inverse quantization and inverse transform processing to obtain a residual block, which is superimposed on the prediction block of the corresponding sub-region to generate a reconstructed block, that is, to reconstruct the current image block.

In some possible implementation manners, after completing S804 at the encoding end, S801 to S804 may also be performed for each of these sub-blocks, and so on, until all sub-blocks cannot be further divided, at this time encoding The end can obtain the leaf nodes under the current image block, and the image area corresponding to these leaf nodes is the CU. Then, the encoding end performs prediction processing on each CU to obtain the corresponding prediction block, and then obtains the corresponding residual block according to the current image block and the prediction block, and then entropy encodes the residual block to generate the corresponding code stream. To encode the current image block.

In this embodiment, when the current image block exceeds the boundary of the current image, it is more complicated to encode and decode the current image block. Therefore, in order to reduce the calculation complexity of the encoding and decoding, the image blocks beyond the boundary of the current image are taken If the above image block division methods described in S801 to S804 are used; and for image blocks that do not exceed the boundary of the current image, the final division method can be determined from the division methods allowed for the current image block, and the final division method The current image block is divided; or, the syntax element of the current image block is obtained by parsing from the code stream, and the current image block is divided according to the division manner indicated by the syntax element corresponding to the current image block. Of course, the division method in the following embodiments may also be implemented to further reduce the calculation complexity of the video sequence codec and improve the compression performance, which is not specifically limited in the embodiments of the present application.

In some possible implementation manners, the decoding end may determine the final division method from the division methods allowed by the current image block by parsing the code stream. For example, the decoding end may determine the division methods allowed by the current image block, and then, according to These current image blocks are allowed to be divided into two bins (ie split_cu_flag, bt_split_flag, bqt_split_type_flag and bqt_split_dir_flag, or the sequence is split_cu_flag, bt_split_flag, bqt_split_split_flag and bqt according to the code and bqt). Analyze the binarized bin of the divided information to determine the final division method of the current image block.

Among them, split_cu_flag is 1, it means that the current image block is allowed to use QT division, split_cu_flag is 0, it means that the current image block is not allowed to use QT division; bt_split_flag is 1, it means that the current image block is allowed to use EQT or BT division, bt_split_flag is 0 , It means that the current image block is not allowed to use EQT and BT division; bqt_split_type_flag is 1, it means that the current image block is allowed to use BT division, bqt_split_type_flag is 0, it means that the current image block is allowed to use EQT division; bqt_split_dir_flag is 1, it means the current image Blocks are allowed to use vertical division, bqt_split_dir_flag is 0, it means that the current image block is allowed to use horizontal division.

If the current image block does not include QT division, the decoder does not need to parse split_cu_flag from the code stream; otherwise, the decoder parses split_cu_flag from the code stream; if split_cu_flag is 1, it means that the current image block allows QT Division, at this time, determine QT as the final division of the current image block; if split_cu_flag is 0, the decoder continues to parse bt_split_flag, if bt_split_flag is 0, the expression of the current image block is not allowed to use EQT and BT division, you do not need to continue Analyze bqt_split_type_flag and bqt_split_dir_flag to directly determine that the current image block is not divided; if bt_split_flag is 1, it indicates that the current image block allows EQT or BT division. At this time, it is necessary to further determine that the current image block uses HEQT, VEQT, HBT and Which way to divide in VBT. Here, if the four divisions of the current image block are allowed to be used, the decoding end parses bqt_split_type_flag and bqt_split_dir_flag from the code stream in sequence (the parsing order can be parsing bqt_split_type_flag, then parsing bqt_split_dir_flag; parsing bqt_split_blit_qg, parsing ); If the current image block allows to use one to three of the above four divisions, the bqt_split_dir_flag and/or bqt_split_type_flag of the current image block need not be parsed from the code stream, but can be directly exported. Thus, the final division method of the current image block can be determined, and the current image block can be divided according to the final division method.

For the encoding end, you can calculate the rate-distortion cost corresponding to the allowed division method of the current image block, and then select the final division method of the current image block according to the rate-distortion cost, and then the current image block according to the final division method To divide.

In the embodiment of the present application, in the current image, when scanning according to the zigzag (Zigzag), when an image block in the current image is scanned, that is, the current image block, the current image block is parsed from the code stream Block information, and then, based on these block information, determine whether the current image block exceeds the boundary of the current image, and determine the forced division method for the current image block that exceeds the boundary of the current image, and perform the forced division in this way to avoid the encoding end being To determine the optimal division method of the current image block and calculate the rate-distortion cost multiple times, there is no need to continuously analyze the division method of the current image block from the code stream, thereby reducing the calculation complexity of the video sequence encoding and decoding and improving the compression performance.

Embodiment 2 of this application:

Based on the foregoing embodiments, in some possible implementation manners, in order to further reduce the computational complexity of the video sequence codec and improve the compression performance, after determining that the current image block does not exceed the boundary of the current image through S802, please refer to As shown by the dotted line in FIG. 8, the above method further includes:

S805: If the current image block does not exceed the boundary of the current image, at least determine the mandatory division method for the current image block according to the size information of the current image block;

Here, when the current image block does not exceed the boundary of the current image, if the current image block is forcibly divided, the computational complexity of encoding and decoding of the video sequence can be further reduced, and the compression performance can be improved. Then, in some possible implementation manners, for a tile that does not exceed the boundary of the current image, S805 may include: according to the size information, such as the width and height of the current image block, calculate the ratio of the width and height of the current image block; If the ratio is greater than the fourth preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method. The fourth preset threshold is a positive integer; if the ratio is less than the fifth preset threshold, the ratio of the height and width of the current image block is greater than The fourth preset threshold determines that the current image block is forcibly divided according to the HBT division method, and the fifth preset threshold is the reciprocal of the fourth preset threshold.

Here, the above fourth preset threshold can be set in the video encoder or video decoder, or can also be parsed from high-level syntax elements (for example, SPS, PPS, or slice header) in the code stream. The fourth preset threshold may take a maximum ratio maxRatio, for example, 4 or 8. The fifth preset threshold can be calculated by taking the reciprocal of the fourth preset threshold, then, the fifth preset threshold can be 1/maxRatio, with a value range of (0, 1), such as 1/4 or 1/8.

In practical applications, for a specific type of image block, in addition to determining the forced division method according to the width and height of the current image block, other parameters may also be combined, such as the type of image block, then the above S805 may also include: Determine whether the current image block is an I slice or I frame; determine whether the width and height of the current image block are equal to the sixth preset threshold. At this time, the sixth preset threshold is a positive integer; if the current If the image block is an I-slice or I frame, and the width and height of the current image block are equal to the sixth preset threshold, it is determined that the current image block is forcibly divided according to the QT division method. In the embodiment of the present application, the sixth preset threshold may be set in the video encoder or video decoder (for example, set to 128 or 256), or high-level syntax elements (for example, SPS, PPS or slice header) parsed.

Among them, the image block is an I slice (slice) or all CUs in an I frame (frame) can only be encoded using intra prediction.

S806: Divide the current image block according to the determined forced division method.

Here, after determining the forced division mode of the current image block through S806, the current image block is forcedly divided according to the determined forced division mode to obtain multiple sub-blocks.

Next, the decoding end can perform S801 to S806 for each of these sub-blocks, and so on, until all the sub-blocks cannot be further divided, at this time, the decoding end can obtain the leaf nodes under the current image block, The image area corresponding to these leaf nodes is the CU. Then, the decoding end parses and obtains the syntax element corresponding to each CU from the code stream, and performs a decoding operation on the CU to obtain a reconstruction signal corresponding to the current image block, that is, to reconstruct the current image block.

In some possible implementation manners, after S806 is performed at the encoding end, S801 to S806 may also be performed for each of these sub-blocks, and so on, until all sub-blocks cannot be further divided, at this time decoding The end can obtain the leaf nodes under the current image block, and the image area corresponding to these leaf nodes is the CU. Then, the coding end performs prediction processing, transformation processing, quantization processing, and entropy coding processing on each CU to realize coding of the current image block.

In the embodiment of the present application, the above method can be used to determine the forced division mode corresponding to the current image block that does not exceed the boundary of the current image. On the contrary, if the current image block does not meet the above conditions, the current image block cannot be determined Corresponding to the mandatory division method, then, at this time, the decoding end can also determine the division method for the current image block in the following manner, for example, determine the final division method from the division methods allowed for the current image block, and follow the final division method Divide the current image block; or, parse out the syntax element corresponding to the current image block from the code stream, and divide the current image block according to the division method indicated by the syntax element.

In the embodiment of the present application, the division method allowed for the image block is a legal division method for decoding. For an image block, it is also possible to determine whether a node is allowed to use VBT division, HBT division, VEQT division, HEQT division, QT division, etc. according to its parameters (such as width, height, image boundary, coding tree level, etc.). If the image block allows one division method, the decoding side can decode the image block normally using this division method; otherwise, the decoding side will decode the image block by default without using this division method for decoding.

In some possible implementation manners, before determining the final division mode from the division modes allowed by the current image block, it is also possible to determine the division mode not allowed by the current image block; where, if the height of the current image block is equal to the seventh The preset threshold determines that the current image block is not allowed to use HBT division and VEQT division; if the width of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use VBT division and HEQT Division method; if the height of the current image block is less than or equal to the eighth preset threshold, it is determined that the current image block is not allowed to use HEQT division; if the width of the current image block is less than or equal to the eighth preset threshold, the current image is determined Blocks are not allowed to use VEQT division.

Here, the seventh preset threshold and the eighth preset threshold may be set in a video encoder or a video decoder, or may be parsed from a high-level syntax element (for example, SPS, PPS, or slice header) in the code stream. The seventh preset threshold may be taken as the minimum preset unit side length minCUSize, that is, the minimum CU side length, for example, 4 or 8. The eighth preset threshold can be obtained by calculating twice the seventh preset threshold, that is, the eighth preset threshold is minCUSize×2, for example, 8 or 16. Of course, the values of the seventh preset threshold and the eighth preset threshold may also be other values, which are not limited to the above examples.

In the embodiment of the present application, according to the block information of the current image block, it is determined that the current image block does not exceed the boundary of the current image. At this time, a forced division method may also be determined for the current image block, and performed according to the determined forced division method Divide, so as to further reduce the computational complexity of video sequence encoding and decoding, thereby improving compression performance.

The method for dividing the above image blocks will be described below with specific examples.

For example, if the decoding side implements the above image block division method, then the method includes:

Step 1: Determine whether the current image block exceeds the boundary of the current image;

In the process of scanning according to the zigzag (Zigzag) in the current image, when the decoding end scans an image block in the current image, that is, the current image block, the current image block is parsed from the current image or from the code stream Block information, and then, based on these block information, determine whether the current image block exceeds the boundary of the current image.

Specifically, the following gives an example of judging that the current image block exceeds the right border, the lower border, and the lower right border of the current image. If one of the following conditions 1 to 3 is true, it means that the current image block exceeds the current image. Boundary, otherwise it means that the current image block does not exceed the boundary of the current image.

Condition 1: If the value of (x, y) in the current image block satisfies x+cW>picW, and y+cH≤picH, the current image block exceeds the right boundary of the current image;

Condition 2: If the value of (x, y) in the current image block satisfies x+cW≤picW, and y+cH>picH, the current image block exceeds the lower boundary of the current image;

Condition 3: If the value of (x, y) in the current image block satisfies x+cW>picW and y+cH>picH, the current image block exceeds the lower right boundary of the current image.

Among them, the width of the current image is picW, the height is picH, the width of the current image block is cW, the height is cH, (x, y) represents the coordinates of the pixel position of the upper left vertex in the current node relative to the pixel position of the upper left vertex of the current image .

Step 2: When the current image block exceeds the boundary of the current image, determine the forced division method of the current image block.

If the current image block exceeds the boundary of the current image, the forced division method of the current image block can be determined according to one of the following methods.

method one:

When the current image block exceeds the right boundary of the current image: If the width of the current image block is equal to the threshold K, and the height of the current image block is equal to the threshold K, the current image block is forced to use HBT division; otherwise, the current image block is forced to use VBT division . The first preset threshold K may be any integer greater than or equal to 1, for example, 64.

When the current image block exceeds the lower boundary of the current image: if the height of the current image block is equal to the threshold K and the width of the current image block is greater than the threshold K, the current image block is forced to use VBT division; otherwise, the current image block is forced to use HBT division . The threshold K may be any integer greater than or equal to 1, for example, 64.

When the current image block exceeds the lower right border of the current image: the current image block is forced to use QT division.

Method Two:

When the current image block exceeds the right boundary of the current image: If the width of the current image block is equal to the threshold M and the height of the current image block is equal to the threshold L, the current image block is forced to use HBT division; otherwise, the current image block is forced to use VBT division . The threshold M and the threshold L may be integers greater than or equal to 32, for example, the threshold M is 64 and the threshold L is 128.

When the current image block exceeds the lower boundary of the current image: If the height of the current image block is equal to the threshold M and the width of the current image block is equal to the threshold L, the current image block is forced to use VBT division; otherwise, the current image block is forced to use HBT division . The threshold M and the threshold L may be integers greater than or equal to 32, for example, the threshold M is 64 and the threshold L is 128.

After step 1, step 3 can also be performed, and step 3 and step 2 are not in order.

Step 3: When the current image block does not exceed the image boundary, determine the division method of the current image block;

Step 3.1: Determine the forced division method of the current image block;

The forced division of the current image block can be derived by one of the following methods, for example:

If the width-to-height ratio of the current image block is greater than the threshold maxRatio, the current image block is forced to use VBT division;

If the ratio of the height and width of the current image block is greater than the threshold maxRatio (that is, the ratio of the width and height of the current image block is less than the threshold 1/maxRatio), the current image block is forced to use HBT division;

The threshold maxRatio may be an integer greater than or equal to 1, for example, 4 or 8.

If the image type of the current image block is I frame, and the current width and height are both the sixth preset threshold S, then the current image block is forced to use QT division, where S is an integer greater than or equal to 1, such as 128 Or 256.

If the forced division method of the current image block cannot be obtained by the above-mentioned pushing method, it indicates that there is no forced division method for the current image block. At this time, the following step 3.2 or step 3.3 may be executed to determine the division method of the current image block.

Step 3.2: Determine the allowed division method of the current image block;

The division method allowed for the current image block is the legal division method for decoding. For an image block, you can also determine whether the image block allows VBT division, HBT division, VEQT division, HEQT division, and QT division based on its parameters (such as width, height, image boundary, coding tree level, etc.). If a division method is allowed, the decoder can use this division method to decode normally when decoding the image block; otherwise, the decoder will not use this division method for decoding by default when decoding the image block.

More specifically, some examples are given below to determine whether one or more division methods are not allowed for an image block: If the height of the current image block is equal to the seventh preset threshold minCUSize, the current image block is not allowed to use HBT division. Among them, minCUSize is called the minimum CU side length, for example, equal to 4 or 8.

If the width of the current image block is equal to the seventh preset threshold minCUSize, the current image block is not allowed to use VBT division. Among them, minCUSize is called the minimum CU side length, for example, equal to 4 or 8.

If the height of the current image block is less than or equal to the eighth preset threshold minCUSize×2, or the width of the current image block is equal to the seventh preset threshold minCUSize, the current image block is not allowed to use HEQT division. Among them, minCUSize is called the minimum CU side length, for example, equal to 4 or 8.

If the width of the current image block is less than or equal to the eighth preset threshold minCUSize×2, or the height of the current image block is equal to the seventh preset threshold minCUSize, the current image block is not allowed to use VEQT division. Among them, minCUSize is called the minimum CU side length, for example, equal to 4 or 8.

In the embodiment of the present application, other methods may also be used to determine the division method allowed for the current image block, which is not specifically limited herein.

Step 3.3: Determine the division method indicated by the syntax element corresponding to the current image block;

In addition to the deduction method of the current image block according to step 3.2, the syntax element corresponding to the current image block can also be parsed in the code stream, and the division method corresponding to the current image block during encoding can be obtained from the syntax element.

Step 4: Divide the current image block according to the division method determined for the current image block to obtain all leaf nodes, ie CUs, with the current image block as the follow-up node;

The decoding end divides the current image block according to the division mode determined for the current image block, obtains corresponding child nodes, and determines the division mode for each child node in turn, and then determines the division mode. If the current image block is no longer divided, the current image block is CU.

Step 5: Analyze and obtain the syntax elements of each CU from the code stream and perform a decoding operation on the CU to obtain the reconstruction block corresponding to the current image block.

Parse the syntax elements of each CU from the code stream to obtain prediction information and residual information for each CU and each sub-region, and perform inter-prediction processing or intra prediction on each sub-region according to the corresponding prediction information of each sub-region After processing, an inter prediction block or an intra prediction block of each sub-region is obtained. According to the residual information of each sub-region, the transform coefficients are subjected to inverse quantization and inverse transform processing to obtain a residual block, which is superimposed on the prediction block of the corresponding sub-region to generate a reconstructed block, that is, to reconstruct the current image block.

Based on the same inventive concept as the above method, an embodiment of the present application further provides an image block dividing device, which can be applied to a video encoder and a video decoder.

10 is a schematic structural diagram of an image block division device in an embodiment of the present application. As shown in FIG. 10, the image block division device 100 includes: an acquisition unit 101, a judgment unit 102, a determination unit 103, and a division unit 104; Unit 101, used to obtain the block information of the current image block in the current image; judgment unit 102, used to determine whether the current image block exceeds the boundary of the current image based on the block information; determination unit 103, used if the current image block exceeds the current image , The boundary of the current image block is determined to be a forced division mode; the division unit 104 is used to divide the current image block according to the forced division mode.

On the basis of the above technical solution, the determining unit is specifically used to compare the size information of the current image block with a preset threshold to determine the corresponding forced division method for the current image block, and the size information is obtained from the block information;

Based on the above technical solution, the determination unit includes: a first determination subunit and a second determination subunit; the first determination subunit is used when the current image block exceeds the right boundary of the current image, if the comparison result indicates that the current The width of the image block is equal to the first preset threshold, and the height of the current image block is greater than or the first preset threshold, it is determined that the current image block is forcibly divided according to the horizontal binary tree HBT division; if the comparison result indicates that the width of the current image block is not Is equal to the first preset threshold, and the height of the current image block is less than or equal to or the first preset threshold, it is determined that the current image block is forcibly divided according to the vertical binary tree VBT division method, the first preset threshold is a positive integer; the second determination The subunit is used to determine the current when the current image block exceeds the right boundary of the current image, if the comparison result indicates that the width of the current image block is equal to the second preset threshold and the height of the current image block is equal to the third preset threshold The image blocks are forcibly divided according to the HBT division method; if the comparison result indicates that the width of the current image block is not equal to the second preset threshold, and the height of the current image block is not equal to the third preset threshold, it is determined that the current image block is forced to follow the VBT The division is divided; the second preset threshold is less than the third preset threshold.

Based on the above technical solution, the determination unit includes: a third determination subunit and a fourth determination subunit; the third determination subunit is used when the current image block exceeds the lower boundary of the current image, if the comparison result indicates that the current The width of the image block is greater than the first preset threshold, and the height of the current image block is equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; also used if the comparison result indicates that the width of the current image block is less than Or equal to the first preset threshold, and the height of the current image block is not equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method, the first preset threshold is a positive integer; or, the fourth determiner Unit for determining the current image block if the comparison result indicates that the height of the current image block is equal to the second preset threshold and the width of the current image block is equal to the third preset threshold when the current image block exceeds the lower boundary of the current image It is forcibly divided according to the VBT division; the comparison result indicates that the width of the current image block is not equal to the second preset threshold and the height of the current image block is not equal to the third preset threshold, which determines that the current image block is forcibly divided according to the HBT division; The second preset threshold is less than the third preset threshold.

Based on the above technical solution, the second preset threshold is an integer greater than or equal to 32.

Based on the above technical solution, the second preset threshold is 64, and the third preset threshold is 128.

Based on the above technical solution, the determining unit is specifically configured to determine that the current image block is forcibly divided according to the quadtree QT division method when the current image block exceeds the right boundary of the current image and exceeds the lower boundary of the current image.

Based on the above technical solution, a judgment unit is used to obtain the coordinates (x, y) of a pixel in the current image block according to the block information; determine whether the coordinates (x, y) of the pixel satisfy the preset condition, If the pixel coordinates (x, y) meet the first preset condition, it means that the pixel exceeds the right boundary of the current image, if the pixel coordinates (x, y) meet the second preset condition, it means that the pixel exceeds the current image If the coordinates (x, y) of the pixel point meet the third preset condition, it means that the pixel point exceeds the right boundary of the current image and exceeds the lower boundary of the current image.

Based on the above technical solution, the pixel coordinates (x, y) are the coordinates of the pixel position of the upper left vertex in the current image block relative to the pixel position of the upper left vertex of the current image; accordingly, the first preset condition is: pixels The coordinates (x, y) of the point satisfy x+cW>picW, and y+cH≤picH; the second preset condition is: the coordinates (x, y) of the pixel point satisfy x+cW≤picW, and y+cH> picH; the third preset condition is: the coordinates (x, y) of the pixels satisfy x+cW>picW, and y+cH>picH; where cW is the width of the current image block, and cH is the height of the current image block, picW is the width of the current image, and picH is the height of the current image.

On the basis of the above technical solution, the determining unit is also used to determine a mandatory division method for the current image block based on at least the size information of the current image block if the current image block does not exceed the boundary of the current image. The size information is obtained from the block information ; The division unit is also used to divide the current image block according to the determined forced division method.

Based on the above technical solution, the determination unit further includes: a calculation subunit, a fifth determination subunit, and a sixth determination subunit; the calculation subunit is used for calculating the ratio of the width to the height of the current image block according to the size information The fifth determination subunit is used to determine that the current image block is forcibly divided according to the VBT division method if the ratio is greater than the fourth preset threshold, and the fourth preset threshold is a positive integer; the sixth determination subunit is used for the ratio If it is smaller than the fifth preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method, and the fifth preset threshold is the reciprocal of the fourth preset threshold.

Based on the above technical solution, the determination unit further includes: a determination subunit and a seventh determination subunit; a determination subunit, used to determine whether the current image block is an I-strip or an I frame; and also used to determine the current image block Whether the width and height of are equal to the sixth preset threshold, and the sixth preset threshold is a positive integer; the seventh determination subunit is used if the current image block is an I-strip or I frame, and the width and height of the current image block If they are all equal to the sixth preset threshold, it is determined that the current image block is forcibly divided according to the QT division method.

Based on the above technical solution, the division unit is also used to determine the final division method from the division methods allowed for the current image block when the mandatory division method is not determined for the current image block, and to determine the current division method according to the final division method. The image block is divided; or, when a mandatory division method is not determined for the current image block, the current image block is divided according to the division method indicated by the syntax element corresponding to the current image block.

On the basis of the above technical solution, the dividing unit is also used to determine the divisions that are not allowed to be used by the current image block according to the size information of the current image block before dividing the current image block according to the allowed division method of the current image block Method; wherein, if the height of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use HBT division and VEQT division, the seventh preset threshold is the side length of the smallest coding unit CU; If the width of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use the VBT division method and the HEQT division method; if the height of the current image block is less than or equal to the eighth preset threshold, the current image block is determined HEQT division is not allowed. The eighth preset threshold is twice the seventh preset threshold; if the width of the current image block is less than or equal to the eighth preset threshold, it is determined that the current image block is not allowed to use VEQT division .

It should be noted that the above acquisition unit 101, judgment unit 102, determination unit 103, and division unit 104 can be applied to the image block division process at the encoding end or the decoding end.

It should also be noted that, for the specific implementation process of the obtaining unit 101, the determining unit 102, the determining unit 103, and the dividing unit 104, reference may be made to the detailed description of the corresponding embodiment in FIG. 8, and for the sake of brevity of the description, no further description is provided here.

Based on the same inventive concept as the above method, embodiments of the present application provide a video encoding method, which can be applied to the encoding end described in any one of the above technical solutions. The video coding method includes: performing the image block division method as described in one or more embodiments above to divide the current coding block; predicting the CU divided by the current coding block to obtain the corresponding prediction block; according to the current coding Block and prediction block to obtain the corresponding residual block; entropy coding the residual block to generate the corresponding code stream.

Here, the encoding end performs S801 to S806 for this current encoding block and each sub-block divided by it, until all sub-blocks cannot be further divided, at this time, the encoding end can obtain the leaf nodes under the current image block, these leaves The image area corresponding to the node is the CU. Then, the encoding end performs prediction processing on each CU to obtain the corresponding prediction block, and then obtains the corresponding residual block according to the current image block and the prediction block, and then entropy encodes the residual block to generate the corresponding code stream. To encode the current image block.

Based on the same inventive concept as the above method, embodiments of the present application provide a video decoding method, which can be applied to the decoding end described in any one of the above technical solutions. The video decoding method includes: performing the image block division method as described in one or more embodiments above to divide the current decoding block; predicting the CU divided by the current decoding block to obtain the corresponding prediction block; according to The residual block and the prediction block parsed in the code stream are used to reconstruct the current decoding block.

Here, the decoding end performs S801 to S806 for the current decoding block and each sub-block divided by it until all sub-blocks cannot be further divided, at this time the decoding end can obtain the leaf nodes under the current image block, these leaves The image area corresponding to the node is the CU. Then, the decoding end parses and obtains the syntax elements corresponding to each CU from the code stream, obtains the prediction information and residual information of each CU and each sub-region, and can perform inter-frame on each sub-region according to the corresponding prediction information of each sub-region The prediction process or the intra prediction process obtains the inter prediction block or the intra prediction block of each sub-region. According to the residual information of each sub-region, the transform coefficients are subjected to inverse quantization and inverse transform processing to obtain a residual block, which is superimposed on the prediction block of the corresponding sub-region to generate a reconstructed block, that is, to reconstruct the current image block.

Based on the same inventive concept as the above method, an embodiment of the present application provides a video encoder for encoding an image block, including: performing an image block division device as described in one or more of the above embodiments, wherein , The image block dividing device is used to obtain the block information of the current coding block from the current image. The current image block is the image block to be coded in the current image; according to the block information, it is determined whether the current coding block exceeds the boundary of the current coding image; if the current If the coding block exceeds the boundary of the current coded image, a forced division method is determined for the current coding block, and the current coding block is divided according to the forced division method; the first prediction processing unit is used to predict the CU divided by the current coding block, Obtain the corresponding prediction block; the residual calculation unit, used to obtain the corresponding residual block according to the current coding block and the prediction block; the entropy coding unit, used to entropy encode the residual block to generate the corresponding code stream.

Based on the same inventive concept as the above method, embodiments of the present application provide a video decoder for decoding an image block from a code stream, including: performing an image as described in one or more embodiments above Block dividing device, wherein the image block dividing device is used to obtain the block information of the current decoded block from the code stream, the current decoded block is the image block to be decoded in the current image; according to the block information, it is judged whether the current decoded block exceeds the current decoded image The boundary of the current decoding block; if the current decoding block exceeds the boundary of the current decoded image, determine the mandatory division mode for the current decoding block, and divide the current decoding block according to the mandatory division mode; the second prediction processing unit is used to divide the current decoding block The CU performs prediction to obtain the corresponding prediction block; the reconstruction unit is used to reconstruct the current decoding block according to the residual block and the prediction block parsed from the code stream.

Based on the same inventive concept as the above method, embodiments of the present application provide an apparatus for encoding video data. The apparatus includes: a memory for storing video data, and the video data includes one or more image blocks; video encoding Is used to obtain the block information of the current encoding block from the current image. The current image block is the image block to be encoded in the current image; according to the block information, it is determined whether the current encoding block exceeds the boundary of the current encoding image; if the current encoding block exceeds At the boundary of the current coded image, a mandatory division method is determined for the current coding block, and the current coding block is divided according to the mandatory division method; the sub-blocks divided by the current coding block are coded to obtain the code stream corresponding to the current coding block.

Based on the same inventive concept as the above method, embodiments of the present application provide an apparatus for decoding video data. The apparatus includes: a memory for storing video data in the form of a code stream; and a video decoder for extracting data from the code stream Obtain the block information of the current decoded block. The current decoded block is the image block to be decoded in the current image; according to the block information, determine whether the current decoded block exceeds the boundary of the current decoded image; if the current decoded block exceeds the boundary of the current decoded image, it is The current decoding block determines the mandatory division method, and divides the current decoding block according to the mandatory division method; predicts the CU divided by the current decoding block to obtain the corresponding prediction block; according to the residual block and prediction parsed from the code stream Block to reconstruct the current decoded block.

Based on the same inventive concept as the above method, embodiments of the present application provide an encoding device, including: a non-volatile memory and a processor coupled to each other, and the processor calls program codes stored in the memory to execute, for example, Part or all of the steps of the image block division method described in the above one or more embodiments.

Based on the same inventive concept as the above method, an embodiment of the present application provides a decoding device, including: a non-volatile memory and a processor coupled to each other, and the processor calls program codes stored in the memory to execute Part or all of the steps of the image block division method described in the above one or more embodiments.

Based on the same inventive concept as the above method, embodiments of the present application provide a computer-readable storage medium that stores a program code, where the program code includes one or more Instructions for some or all steps of the image block division method described in the embodiments.

Based on the same inventive concept as the above method, embodiments of the present application provide a computer program product that, when the computer program product runs on a computer, causes the computer to execute images as described in one or more of the above embodiments Part or all steps of the block division method.

Those skilled in the art will appreciate that the functions described in conjunction with the various illustrative logical blocks, modules, and algorithm steps described in this disclosure may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions described by the various illustrative logical blocks, modules, and steps may be stored or transmitted as one or more instructions or codes on a computer-readable medium and executed by hardware-based processing units. Computer-readable media may include computer-readable storage media, which corresponds to tangible media, such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another (eg, according to a communication protocol). . In this manner, computer-readable media may generally correspond to (1) non-transitory tangible computer-readable storage media, or (2) communication media, such as signals or carrier waves. Data storage media may 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 implementation of the techniques described in this application. The computer program product may include a computer-readable medium.

By way of example, and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM, or other optical disk storage devices, magnetic disk storage devices, or other magnetic storage devices, flash memory, or may be used to store instructions or data structures The desired program code in the form of and any other medium that can be accessed by the computer. And, any connection is properly called a computer-readable medium. For example, if a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared, radio, and microwave is used to transmit instructions from a website, server, or other remote source, then the coaxial cable Wire, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media. However, it should be understood that the computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other temporary media, but are actually directed to non-transitory tangible storage media. As used herein, magnetic disks and optical discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), and Blu-ray discs, where magnetic discs typically reproduce data magnetically, while optical discs reproduce optically using lasers data. Combinations of the above should also be included in the scope of computer-readable media.

One or more processes such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits To execute instructions. Accordingly, the term "processor" as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functions described in the various illustrative logical blocks, modules, and steps described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or in combination Into the combined codec. Moreover, the techniques can be fully implemented in one or more circuits or logic elements.

The technology of the present application may be implemented in a variety of devices or equipment, including wireless handsets, integrated circuits (ICs), or a set of ICs (eg, chipsets). Various components, modules or units are described in this application to emphasize the functional aspects of the device for performing the disclosed technology, but do not necessarily need to be implemented by different hardware units. In fact, as described above, various units may be combined in a codec hardware unit in combination with suitable software and/or firmware, or by interoperating hardware units (including one or more processors as described above) provide.

In the above embodiments, the description of each embodiment has its own emphasis. For a part that is not detailed in an embodiment, you can refer to the related descriptions of other embodiments.

The above are only exemplary specific implementations of the present application, but the scope of protection of the present application is not limited to this, and any person skilled in the art may easily think of changes or changes within the technical scope disclosed in the present application. Replacement should be covered within the scope of protection of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

An image block division method, characterized in that it includes:

Obtain the block information of the current image block in the current image;

According to the block information, determine whether the current image block exceeds the boundary of the current image;

If the current image block exceeds the boundary of the current image, determine a mandatory division method for the current image block;

Divide the current image block according to the forced division manner.
The method according to claim 1, wherein the determining of a mandatory division method for the current image block includes:

Comparing the size information of the current image block with a preset threshold to determine a corresponding forced division manner for the current image block, the size information is obtained from the block information.
The method according to claim 2, wherein when the current image block exceeds the right boundary of the current image, the comparing the size information of the current image block with a preset threshold is The current image block determines the corresponding mandatory division method, including:

If the width of the current image block is equal to the first preset threshold and the height of the current image block is greater than the first preset threshold, it is determined that the current image block is forcibly divided according to the horizontal binary tree HBT division method; if the The width of the current image block is not equal to the first preset threshold, and the height of the current image block is less than or equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the vertical binary tree VBT division method, the first A preset threshold is a positive integer; or,

If the width of the current image block is equal to the second preset threshold and the height of the current image block is equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method; if the current image The width of the block is not equal to the second preset threshold, and the height of the current image block is not equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; the second preset threshold is less than The third preset threshold.
The method according to claim 2 or 3, wherein when the current image block exceeds the lower boundary of the current image, the comparing the size information of the current image block with a preset threshold is: The current image block determining the corresponding forced division method includes:

If the width of the current image block is greater than the first preset threshold and the height of the current image block is equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; if the current image The width of the block is less than or equal to the first preset threshold, and the height of the current image block is not equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method, and the first preset threshold is Positive integer; or,

If the height of the current image block is equal to the second preset threshold and the width of the current image block is equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; if the current image The width of the block is not equal to the second preset threshold, and the height of the current image block is not equal to the third preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method; the second preset threshold is less than Said third preset threshold.
The method according to claim 3 or 4, wherein the second preset threshold is an integer greater than or equal to 32.
The method of claim 5, wherein the second preset threshold is 64, and the third preset threshold is 128.
The method according to any one of claims 1 to 6, wherein when the current image block exceeds the right boundary of the current image and exceeds the lower boundary of the current image, the current image The block determines the mandatory division method, including:

It is determined that the current image block is forcibly divided according to a quadtree QT division manner.
The method according to any one of claims 1 to 7, wherein the determining whether the current image block exceeds the boundary of the current image according to the block information includes:

Obtain the coordinates (x, y) of a pixel in the current image block according to the block information;

Judging whether the coordinates (x, y) of the pixel point satisfy the preset condition, if the coordinates (x, y) of the pixel point satisfy the first preset condition, it indicates that the pixel exceeds the right boundary of the current image If the coordinates (x, y) of the pixel satisfy the second preset condition, it indicates that the pixel exceeds the lower boundary of the current image, if the coordinates (x, y) of the pixel satisfy the third preset condition , Indicating that the pixel exceeds the right boundary of the current image and exceeds the lower boundary of the current image.
The method according to claim 8, wherein the coordinates (x, y) of the pixels are the coordinates of the pixel position of the upper left vertex in the current image block relative to the pixel position of the upper left vertex of the current image;

Correspondingly, the first preset condition is: the coordinates (x, y) of the pixel point satisfy x+cW>picW, and y+cH≤picH;

The second preset condition is that the coordinates (x, y) of the pixel point satisfy x+cW≤picW, and y+cH>picH;

The third preset condition is that the coordinates (x, y) of the pixel point satisfy x+cW>picW, and y+cH>picH;

Where cW is the width of the current image block, cH is the height of the current image block, picW is the width of the current image, and picH is the height of the current image.
The method according to any one of claims 1 to 9, wherein after the judging whether the current image block exceeds the boundary of the current image according to the block information, the method further comprises:

If the current image block does not exceed the boundary of the current image, at least according to the size information of the current image block to determine a mandatory division method for the current image block, the size information is obtained from the block information;

Divide the current image block according to the determined forced division mode.
The method according to claim 10, wherein the determining of a mandatory division method for the current image block based on at least the size information of the current image block includes:

Calculating the ratio of the width and height of the current image block according to the size information;

If the ratio is greater than a fourth preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method, and the fourth preset threshold is a positive integer;

If the ratio is less than a fifth preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method, and the fifth preset threshold is the reciprocal of the fourth preset threshold.
The method according to claim 10 or 11, wherein the determining the mandatory division method for the current image block at least according to the size information of the current image block includes:

Determine whether the current image block is an I-band or an I-frame;

Determine whether the width and height of the current image block are equal to a sixth preset threshold, and the sixth preset threshold is a positive integer;

If the current image block is an I-slice or an I frame, and the width and height of the current image block are equal to the sixth preset threshold, it is determined that the current image block is forcibly divided according to the QT division method.
The method according to any one of claims 10 to 12, wherein after the determining of a mandatory division method for the current image block at least according to the size information of the current image block, the method further comprises:

When no mandatory division method is determined for the current image block, a final division method is determined from the division methods allowed for the current image block, and the current image block is divided according to the final division method; or,

When no forced division mode is determined for the current image block, the current image block is divided according to the division mode indicated by the syntax element corresponding to the current image block.
The method according to claim 13, wherein before dividing the current image block according to the division method allowed for the current image block, the method further comprises:

According to the size information of the current image block, determine a division mode that the current image block is not allowed to use; wherein,

If the height of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use the HBT division method and the vertical expansion quadtree VEQT division method, and the seventh preset threshold value is the minimum The side length of the coding unit CU;

If the width of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use the VBT division method and the horizontally expanded quadtree HEQT division method;

If the height of the current image block is less than or equal to an eighth preset threshold, it is determined that the current image block does not allow the HEQT division method, and the eighth preset threshold is twice the seventh preset threshold ;

If the width of the current image block is less than or equal to the eighth preset threshold, it is determined that the current image block is not allowed to use the VEQT division method.
An image block dividing device is characterized by comprising:

The obtaining unit is used to obtain the block information of the current image block in the current image;

The judging unit is used to judge whether the current image block exceeds the boundary of the current image according to the block information;

A determining unit, configured to determine a mandatory division method for the current image block if the current image block exceeds the boundary of the current image;

The dividing unit is configured to divide the current image block according to the forced division method.
The apparatus according to claim 15, wherein the determining unit is specifically configured to compare the size information of the current image block with a preset threshold to determine a corresponding forced division method for the current image block, The size information is obtained from the block information.
The apparatus according to claim 16, wherein the determining unit comprises: a first determining subunit and a second determining subunit;

The first determining subunit is configured to: when the current image block exceeds the right boundary of the current image, if the width of the current image block is equal to a first preset threshold, and the height of the current image block is greater than Or a first preset threshold, it is determined that the current image block is forcibly divided according to the horizontal binary tree HBT division method; if the width of the current image block is not equal to the first preset threshold, and the height of the current image block is less than or Equal to or a first preset threshold, determining that the current image block is forcibly divided according to a vertical binary tree VBT division manner, and the first preset threshold is a positive integer;

The second determining subunit is configured to: when the current image block exceeds the right boundary of the current image, if the width of the current image block is equal to a second preset threshold, and the height of the current image block is equal to When the third preset threshold is determined, it is determined that the current image block is forcibly divided according to the HBT division method; if the width of the current image block is not equal to the second preset threshold, and the height of the current image block is not equal to the third A preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; the second preset threshold is smaller than the third preset threshold.
The apparatus according to claim 16 or 17, wherein the determination unit comprises: a third determination subunit and a fourth determination subunit;

The third determining subunit is configured to: when the current image block exceeds the lower boundary of the current image, if the width of the current image block is greater than a first preset threshold, and the height of the current image block is equal to A first preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; it is also used if the width of the current image block is less than or equal to the first preset threshold, and the height of the current image block is not Equal to the first preset threshold, it is determined that the current image block is forcibly divided according to the HBT division method, and the first preset threshold is a positive integer; or,

The fourth determining subunit is configured to, when the current image block exceeds the lower boundary of the current image, if the height of the current image block is equal to the second preset threshold and the width of the current image block is equal to A third preset threshold, it is determined that the current image block is forcibly divided according to the VBT division method; the width of the current image block is not equal to the second preset threshold, and the height of the current image block is not equal to the third preset The threshold value determines that the current image block is forcibly divided according to the HBT division method; the second preset threshold value is smaller than the third preset threshold value.
The apparatus according to claim 17 or 18, wherein the second preset threshold is an integer greater than or equal to 32.
The apparatus of claim 19, wherein the second preset threshold is 64, and the third preset threshold is 128.
The device according to any one of claims 15 to 20, wherein the determining unit is specifically configured to when the current image block exceeds the right boundary of the current image and exceeds the lower boundary of the current image To determine that the current image block is forcibly divided according to the quadtree QT division method.
The device according to any one of claims 15 to 21, wherein the judgment unit is configured to obtain the coordinates (x, y) of a pixel in the current image block according to the block information; Judging whether the coordinates (x, y) of the pixel point satisfy the preset condition, if the coordinates (x, y) of the pixel point satisfy the first preset condition, it indicates that the pixel exceeds the right boundary of the current image , If the coordinates (x, y) of the pixel point meet the second preset condition, it indicates that the pixel exceeds the lower boundary of the current image, if the coordinates (x, y) of the pixel point meet the third pre If the condition is set, it means that the pixel point exceeds the right boundary of the current image and exceeds the lower boundary of the current image.
The device of claim 22, wherein the coordinates (x, y) of the pixels are the coordinates of the pixel position of the upper left vertex in the current image block relative to the pixel position of the upper left vertex of the current image;

Correspondingly, the first preset condition is: the coordinates (x, y) of the pixel point satisfy x+cW>picW, and y+cH≤picH;

The second preset condition is that the coordinates (x, y) of the pixel point satisfy x+cW≤picW, and y+cH>picH;

The third preset condition is: the coordinates (x, y) of the pixel point satisfy x+cW>picW, and y+cH>picH;

Where cW is the width of the current image block, cH is the height of the current image block, picW is the width of the current image, and picH is the height of the current image.
The apparatus according to any one of claims 15 to 23, wherein the determining unit is further configured to, if the current image block does not exceed the boundary of the current image, at least according to the current image block's The size information determines a mandatory division method for the current image block, and the size information is obtained from the block information;

The dividing unit is also used to divide the current image block according to the determined forced division mode.
The apparatus of claim 24, wherein the determination unit further comprises: a calculation subunit, a fifth determination subunit, and a sixth determination subunit;

The calculation subunit is configured to calculate the ratio of the width and height of the current image block according to the size information;

The fifth determining subunit is configured to determine that the current image block is forcibly divided according to the VBT division method if the ratio is greater than a fourth preset threshold, and the fourth preset threshold is a positive integer;

The sixth determining subunit is configured to determine that the current image block is forcibly divided according to the HBT division method if the ratio is less than a fifth preset threshold, and the fifth preset threshold is the fourth preset Reciprocal of the threshold.
The apparatus according to claim 24 or 25, wherein the determination unit further comprises: a determination subunit and a seventh determination subunit;

The judging subunit is used to judge whether the current image block is an I band or an I frame; and also used to judge whether the width and height of the current image block are equal to a sixth preset threshold, and the sixth pre Set the threshold to a positive integer;

The seventh determining subunit is used to determine the current image if the current image block is an I-slice or I frame, and the width and height of the current image block are equal to the sixth preset threshold Blocks are forcibly divided according to the QT division method.
The device according to any one of claims 24 to 26, wherein the dividing unit is further configured to allow the current image block to be used when a forced division method is not determined for the current image block Determine the final division mode in the division mode, and divide the current image block according to the final division mode; or, when no mandatory division mode is determined for the current image block, according to the syntax elements corresponding to the current image block The indicated division manner divides the current image block.
The apparatus according to claim 27, wherein the dividing unit is further configured to divide the current image block according to the current before dividing the current image block according to the allowed division method of the current image block The size information of the image block determines the division method that the current image block is not allowed to use; wherein, if the height of the current image block is equal to the seventh preset threshold, it is determined that the current image block is not allowed to use the HBT division method And the vertical expansion quadtree VEQT division method, the seventh preset threshold is the side length of the smallest coding unit CU; if the width of the current image block is equal to the seventh preset threshold, it is determined that the current The image block is not allowed to use the VBT division method and the horizontally expanded quadtree HEQT division method; if the height of the current image block is less than or equal to the eighth preset threshold, it is determined that the current image block is not allowed to use HEQT division Way, the eighth preset threshold is twice the seventh preset threshold; if the width of the current image block is less than or equal to the eighth preset threshold, it is determined that the current image block is not allowed to be used The division of VEQT.
A video encoding method, characterized in that it includes:

Performing the image block division method according to any one of claims 1 to 14 to divide the current coding block;

Predict the coding unit CU divided by the current coding block to obtain a corresponding prediction block;

Obtain a corresponding residual block according to the current coding block and the prediction block;

Entropy coding the residual block to generate a corresponding code stream.
A video decoding method, characterized in that it includes:

Performing the image block division method according to any one of claims 1 to 14 to divide the current decoded block;

Predict the coding unit CU divided by the current decoding block to obtain a corresponding prediction block;

According to the residual block parsed from the code stream and the prediction block, the current decoding block is reconstructed.
A video encoder, characterized in that the video encoder is used to encode image blocks, including:

The image block dividing device according to any one of claims 15 to 28, wherein the image block dividing device is used to obtain block information of a current coding block from a current image, where the current image block is to be coded in the current image Image block; based on the block information, determine whether the current encoding block exceeds the boundary of the current encoding image; if the current encoding block exceeds the boundary of the current encoding image, determine the mandatory for the current encoding block Dividing mode, and dividing the current coding block according to the mandatory dividing mode;

A first prediction processing unit, configured to predict the coding unit CU divided by the current coding block to obtain a corresponding prediction block;

A residual calculation unit, configured to obtain a corresponding residual block according to the current coding block and the prediction block;

An entropy encoding unit is used to entropy encode the residual block to generate a corresponding code stream.
A video decoder, characterized in that the video decoder is used to decode image blocks from a code stream, including:

The image block dividing device according to any one of claims 15 to 28, wherein the image block dividing device is used to obtain block information of a current decoded block from a code stream, and the current decoded block is to be decoded in the current image An image block; according to the block information, determine whether the current decoded block exceeds the boundary of the current decoded image; if the current decoded block exceeds the boundary of the current decoded image, determine the mandatory for the current decoded block Dividing mode, and dividing the current decoding block according to the mandatory dividing mode;

A second prediction processing unit, configured to predict the coding unit CU divided by the current decoding block to obtain a corresponding prediction block;

The reconstruction unit is configured to reconstruct the current decoding block according to the residual block parsed from the code stream and the prediction block.
A video encoding and decoding device, comprising: a non-volatile memory and a processor coupled to each other, the processor calling program code stored in the memory to perform the method according to any one of claims 1 to 14. .