Video encoding method and apparatus, video decoding method and apparatus, computer-readable medium, and electronic device

Patent metadata

Field	Value
Publication number	US-12177464-B2
Application number	US-202217989400-A
Country	US
Kind code	B2
Filing date	Nov 17, 2022
Priority date	Feb 21, 2021
Publication date	Dec 24, 2024
Grant date	Dec 24, 2024

Abstract

A video decoding method includes: segmenting to-be-decoded coefficients according to a scan order of a scan region-based coefficient coding (SRCC) scan region in a coding block of a video image frame to obtain one or more coefficient parts each including a plurality of coefficients; decoding a coefficient part all zero flag of each of the coefficient parts to obtain a value of the coefficient part all zero flag; decoding a significant flag of each coefficient in the coefficient part according to the scan order in response to the value of the coefficient part all zero flag being a preset first value, the significant flag being used for indicating whether the coefficient is a non-zero coefficient; and setting the significant flag of each coefficient in the coefficient part to zero, in response to the value of the coefficient part all zero flag being a preset second value.

First claim

What is claimed is:

1. A video decoding method, executed by an electronic device, the method comprising:
segmenting to-be-decoded coefficients according to a scan order of a scan region-based coefficient coding (SRCC) scan region in a coding block of a video image frame to obtain one or more coefficient parts;
decoding a coefficient part all zero flag of each of the coefficient parts to obtain a value of the coefficient part all zero flag, the coefficient part all zero flag being used for indicating whether all coefficients in the coefficient part are zero;
decoding a significant flag of each coefficient in the coefficient part according to the scan order in response to the value of the coefficient part all zero flag being a preset first value, the significant flag being used for indicating whether the coefficient is a non-zero coefficient; and
skipping decoding the significant flag and setting the significant flag of each coefficient in the coefficient part to zero, in response to the value of the coefficient part all zero flag being a preset second value.

2. The video decoding method according to claim 1 , wherein segmenting the to-be-decoded coefficients comprises:
obtaining a coefficient part length, the coefficient part length being used for representing a maximum number of coefficients comprised in the coefficient part; and
determining consecutive to-be-decoded coefficients according to the scan order of the SRCC scan region, and forming a number of coefficients equal to or less than the coefficient part length into one coefficient part.

3. The video decoding method according to claim 2 , wherein the coefficient part length is a constant determined according to a maximum transformation unit size or is a dynamic parameter determined according to attribute information of the coding block.

4. The video decoding method according to claim 3 , wherein the attribute information of the coding block includes at least one of: a size of a current transformation unit, a shape of the current transformation unit, coordinates of the SRCC scan region, and a number of coefficients in the SRCC scan region.

5. The video decoding method according to claim 1 , wherein decoding the coefficient part all zero flag of each of the coefficient parts comprises:
determining that a decoding method of the coefficient part all zero flag is bypass decoding or conventional decoding;
decoding the coefficient part all zero flag through a bypass decoding engine in response to the decoding method of the coefficient part all zero flag being bypass decoding; and
decoding the coefficient part all zero flag through a conventional decoding engine based on a context model in response to the decoding method of the coefficient part all zero flag being conventional decoding.

6. The video decoding method according to claim 5 , wherein decoding the coefficient part all zero flag comprises:
obtaining a model selection manner corresponding to the SRCC scan region, and determining a context index increment according to the model selection manner;
selecting a context model corresponding to the coefficient part all zero flag according to the context index increment; and
arithmetically decoding the coefficient part all zero flags based on the selected context model through a conventional decoding engine.

7. The video decoding method according to claim 6 , wherein determining the context index increment comprises:
setting the context index increment according to a shape of the SRCC scan region in response to the model selection manner being a first mode;
setting the context index increment according to an area of the SRCC scan region in response to the model selection manner being a second mode; and
setting the context index increment according to the preset first value in response to the model selection manner being a third mode.

8. The video decoding method according to claim 7 , wherein setting the context index increment comprises:
obtaining a region width and a region height of the SRCC scan region;
setting an initial value of the context index increment according to a value relationship between the region width and the region height;
setting an initial value increment of the context index increment according to a value ratio relationship between the region width and the region height; and
setting the context index increment according to the initial value and the initial value increment.

9. The video decoding method according to claim 8 , wherein setting the initial value of the contextual index increment comprises:
setting the initial value of the context index increment to the preset second value in response to a value of the region width being equal to a value of the region height;
setting the initial value of the context index increment to a preset third value in response to the region width being less than the region height; and
setting the initial value of the context index increment to a preset fourth value in response to the region width being greater than the region height.

10. The video decoding method according to claim 8 , wherein setting the initial value increment of the context index increment comprises:
calculating a value ratio between the larger one and the smaller one of the region width and the region height; and
comparing the value ratio with a plurality of preset ratio thresholds and setting the initial value increment of the context index increment according to a result of the comparison.

11. The video decoding method according to claim 8 , wherein setting the context index increment comprises:
setting the context index increment to the initial value in response to the value of the region width being equal to the value of the region height; and
setting the context index increment to a sum of the initial value and the initial value increment in response to the value of the region width being not equal to the value of the region height.

12. The video decoding method according to claim 7 , wherein setting the context index increment comprises:
obtaining a region width and a region height of the SRCC scan region;
determining a region area of the SRCC scan region according to the region width and the region height; and
comparing the region area with a plurality of preset area thresholds and setting the context index increment according to a result of the comparison.

13. The video decoding method according to claim 1 , further comprising:
determining whether a preset decoding skip condition is met; and
skipping the operation of decoding the coefficient part all zero flag and setting the value of the coefficient part all zero flag to the preset second value, in response to the decoding skip condition being satisfied.

14. The video decoding method according to claim 13 , wherein decoding the skip condition comprises at least one of:
the number of coefficients in the coefficient part is less than a preset number threshold; and
an area proportion that the SRCC scan region accounts for in the coding block is less than a preset proportion threshold.

15. The video decoding method according to claim 1 , wherein the particular coefficient part is located at a particular position in the SRCC scan region.

16. The video decoding method according to claim 15 , wherein the particular coefficient part is a first coefficient part or a last coefficient part in the scan order.

17. The video decoding method according to claim 1 , wherein the method is applied to a coding block satisfying a preset encoding condition, and the coding block satisfying the preset encoding conditi

Assignees

• Tencent Tech Shenzhen Co Ltd

Inventors

• Hu Ye

Classifications

• H04N19/46

  Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) · CPC title

• H04N19/176 Primary

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

• H04N19/119

  Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks · CPC title

• H04N19/70

  characterised by syntax aspects related to video coding, e.g. related to compression standards · CPC title

• H04N19/129

  Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO] · CPC title