Coding efficiency of boundary coordinates of SRCC scan region

Patent metadata

Field	Value
Publication number	US-12316845-B2
Application number	US-202217978092-A
Country	US
Kind code	B2
Filing date	Oct 31, 2022
Priority date	Feb 22, 2021
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

A video decoding method includes obtaining a size of a coding block of a video image frame, and decoding a bitstream of the coding block to obtain a value of a range variable associated with a SRCC scan region of the coding block. The range variable includes a width range variable and a height range variable. Each of the width range variable and the height range variable are obtained by comparing a prefix value to one or more predefined value intervals. The method further includes determining a horizontal coordinate of boundary coordinates of the SRCC scan region according to a difference between the width of the coding block and the width range variable and determining a vertical coordinate of the boundary coordinates of the SRCC scan region according to a difference between the height of the coding block and the height range variable.

First claim

What is claimed is:

1. A video decoding method, comprising:
obtaining a size of a coding block of a video image frame, the size of the coding block comprising a width and a height of the coding block;
decoding a bitstream of the coding block to obtain a value of a range variable associated with a scan region-based coefficient coding (SRCC) scan region of the coding block, the range variable comprising a width range variable corresponding to a width of the SRCC scan region and a height range variable corresponding to a height of the SRCC scan region, wherein each of the width range variable and the height range variable are obtained by comparing a prefix value of the width range variable and a prefix value of the height range variable respectively to one or more predefined value intervals; and
determining a horizontal coordinate of boundary coordinates of the SRCC scan region according to a difference between the width of the coding block and the width range variable and determining a vertical coordinate of the boundary coordinates of the SRCC scan region according to a difference between the height of the coding block and the height range variable, wherein the decoding comprises one of:
(i) sequentially decoding a binary symbol corresponding to index numbers in an ascending order of the index numbers in the bitstream of the coding block to obtain a value of the binary symbol, setting a position variable to a current index number corresponding to the binary symbol in response to the value of the binary symbol being a preset first value, and setting one of the width range variable or the height range variable associated with the SRCC scan region of the coding block according to a value of the position variable; and
(ii) determining the one or more predefined value intervals, the value intervals each comprising an interval lower limit and an interval upper limit, decoding the bitstream of the coding block to obtain the prefix value of one of the width range variable or the height range variable, determining one of the one or more predefined value intervals corresponding to the one of the width range variable or the height range variable according to a comparison of the prefix value of the one of the width range variable or the height range variable and an interval upper limit of a first value interval, determining a compensation value according to an interval lower limit of the one of the one or more predefined value intervals, and determining the value of the one of the width range variable or the height range variable according to the compensation value.

2. The video decoding method according to claim 1 , wherein the determining comprises:
determining the horizontal coordinate and the vertical coordinate of the boundary coordinates of the SRCC scan region according to a following formula:
SRx=width-1-width_minus1_minus_scan_region_x,
SRy=height-1-height_minus1_minus_scan_region_y,

wherein SRx represents the horizontal coordinate, SRy represents the vertical coordinate, width represents the width of the coding block, height represents the height of the coding block, width_minus1_minus_scan_region_x represents the width range variable, and height_minus1_minus_scan_region_y represents the height range variable.

3. The video decoding method according to claim 1 , wherein the decoding comprises:
sequentially decoding the binary symbol corresponding to the index numbers in the ascending order of the index numbers in the bitstream of the coding block to obtain the value of the binary symbol;
in response to the value of the binary symbol being the preset first value, setting the position variable to the current index number corresponding to the binary symbol; and
setting the one of the width range variable or the height range variable associated with the SRCC scan region of the coding block according to the value of the position variable.

4. The video decoding method according to claim 3 , wherein the setting the one of the width range variable or the height range variable comprises:
comparing the value of the position variable with a preset second value defining one of the one or more predefined value intervals;
setting the one of the width range variable or the height range variable to the preset second value in response to the value of the position variable being less than or equal to the preset second value; and
in response to the value of the position variable being greater than the preset second value, determining the prefix value of the one of the width range variable or the height range variable according to the value of the position variable and determining a suffix value by decoding other binary symbols after the binary symbol associated with the position variable, and setting the one of the width range variable or the height range variable to a sum of the prefix value and the suffix value.

5. The video decoding method according to claim 4 , wherein the determining the prefix value according to the value of the position variable comprises:
performing mapping processing on the value of the position variable according to a first mapping vector to obtain a first mapping value corresponding to the value of the position variable; and
determining the prefix value according to the first mapping value.

6. The video decoding method according to claim 4 , wherein the determining the suffix value comprises:
determining a number of the other binary symbols to be decoded according to the value of the position variable; and
decoding the determined number of the other binary symbols after the binary symbol associated with the position variable to obtain the suffix value.

7. The video decoding method according to claim 6 , wherein the decoding the determined number of the other binary symbols comprises:
entropy decoding the determined number of the other binary symbols after the binary symbol associated with the position variable based on a bypass decoding manner; and
determining the number as a length len of a fixed-length code, and performing inverse binarization on a result of the entropy decoding based on the fixed-length code of len bits to obtain the suffix value.

8. The video decoding method according to claim 3 , wherein the sequentially decoding the binary symbol comprises:
setting a context index increment corresponding to the binary symbol;
determining a context model corresponding to the binary symbol according to the set context index increment; and
arithmetically decoding the binary symbol based on the context model through a context adaptive binary arithmetic coding (CABAC) decoding engine to obtain the value of the binary symbol.

9. The video decoding method according to claim 8 , wherein the setting the context index increment comprises:
setting the context index increment to the current index number corresponding to the binary symbol.

10. The video decoding method according to claim 8 , wherein the setting the context index increment comprises:
setting an initial value of the context index increment according to channel information of the coding block;
determining a shift according to the channel information of the coding block and the size of the coding block; and
setting the context index increment corresponding to the binary symbol according to the initial value, the current index number, and the shift.

11. The video decoding method according to claim 10 , wherein the setting the initial value comprises:
setting the initial value of the context index increment to a preset third value in response to the coding block being a luma block; and
determining a fourth value related to the size of the coding block and increasing the preset third value by the

Assignees

• Tencent Tech Shenzhen Co Ltd

Inventors

• Hu Ye
• Wang Liqiang

Classifications

• H04N19/186

  the unit being a colour or a chrominance component · CPC title

• H04N19/184

  the unit being bits, e.g. of the compressed video stream · CPC title

• H04N19/176 Primary

  the region being a block, e.g. a macroblock · CPC title

• H04N19/172

  the region being a picture, frame or field · CPC title

• H04N19/167

  Position within a video image, e.g. region of interest [ROI] · CPC title