Encoder, a decoder and corresponding methods using intra mode coding for intra prediction

Patent metadata

Field	Value
Publication number	US-12348770-B2
Application number	US-202117407517-A
Country	US
Kind code	B2
Filing date	Aug 20, 2021
Priority date	Feb 25, 2019
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

It is provided a method of prediction coding of a current block, comprising: obtaining an intra prediction mode of a left neighbor block of the current block and an intra prediction mode of an above neighbor block of the current block; constructing a Most Probable Mode (MPM) list of intra prediction modes for the current block, the MPM list comprising at least 5 entries of intra prediction modes as follows: {ang, 2+((ang+61)%64), 2+((ang−1)%64), 2+((ang+60)%64), 2+((ang) %64)} when at least a first condition is fulfilled, where ang represents the intra prediction mode of the left neighbor block or the intra prediction mode of the above neighbor block.

First claim

What is claimed is:

1. A method of prediction coding of a current block implemented by a decoding device or an encoding device, comprising:
obtaining an intra prediction mode of a left neighbor block of the current block;
obtaining an intra prediction mode of an above neighbor block of the current block; and
constructing a Most Probable Mode (MPM) list of intra prediction modes for the current block, the MPM list consisting 6 entries of intra prediction modes in the following order:
{ang, 2+((ang+61)%64), 2+((ang−1)%64), 2+((ang+60)%64), 2+((ang) %64)} when at least a first condition is fulfilled, wherein the first condition includes that the intra prediction mode of the left neighbor block and the intra prediction mode of the above neighbor block are the same angular mode, and wherein ang represents the intra prediction mode of the left neighbor block or the intra prediction mode of the above neighbor block.

2. The method according to claim 1 , wherein the MPM list consists of the 6 entries of intra prediction modes when the first condition and a second condition are fulfilled, wherein the second condition includes that the current block is coded with Intra Sub Partition (ISP) mode.

3. The method according to claim 1 , further comprising coding the intra prediction mode of the current block based on the generated MPM list.

4. The method according claim 1 , further comprising determining the intra prediction mode of the current block and, when the determined intra prediction mode of the current block is listed in the MPM list, coding the determined intra prediction mode of the current block by a corresponding index of the MPM list.

5. The method according to claim 1 , further comprising:
determining whether the intra prediction mode of the current block is a PLANAR mode or not; and
signaling that the intra prediction mode of the current block is not the PLANAR mode by means of a flag when it is determined that the intra prediction mode of the current block is not the PLANAR mode.

6. The method according to claim 1 , further comprising multiple reference line coding using the MPM list.

7. The method according to claim 1 , wherein the intra prediction mode of the above neighbor block is determined to be PLANAR, if there is no intra predicted above neighbor block present, and the intra prediction mode of the left neighbor block is determined to be PLANAR, if there is no intra predicted left neighbor block present.

8. The method according to claim 1 , wherein a top left corner of the left neighbor block is located at (xCb−1, yCb+cbHeight−1) and the top left corner of the above neighbor block is located at (xCb+cbWidth−1, yCb−1), where xCb, yCb, cbHeight and cbWidth denote a location of the top left corner of the current block in a width direction, a location of the top left corner of the current block in a height direction, a height of the current block and a width of the current block, respectively.

9. A method of prediction coding of a current block implemented by a decoding device or an encoding device, comprising:
obtaining an intra prediction mode of a left neighbor block of the current block;
obtaining an intra prediction mode of an above neighbor block of the current block; and
constructing a Most Probable Mode (MPM) list of intra prediction modes for the current block, the MPM list consisting 6 entries of intra prediction modes in the following order:
{PLANAR, ang, 2+((ang+61)%64), 2+((ang−1)%64), 2+((ang+60)%64), 2+((ang) %64)} when at least a first condition is fulfilled, wherein the first condition includes that only one of the intra prediction mode of the left neighbor block and the intra prediction mode of the above neighbor block is an angular mode, wherein ang represents the angular mode.

10. The method according to claim 9 , wherein the MPM list consists of the 6 entries of intra prediction modes when the first condition and a second condition are fulfilled, wherein the second condition includes that the current block is coded with ISP mode.

11. The method according to claim 9 , further comprising coding the intra prediction mode of the current block based on the generated MPM list.

12. The method according claim 9 , further comprising determining the intra prediction mode of the current block and, when the determined intra prediction mode of the current block is listed in the MPM list, coding the determined intra prediction mode of the current block by a corresponding index of the MPM list.

13. The method according to claim 9 , further comprising:
determining whether the intra prediction mode of the current block is a PLANAR mode or not; and
signaling that the intra prediction mode of the current block is not the PLANAR mode by means of a flag when it is determined that the intra prediction mode of the current block is not the PLANAR mode.

14. The method according to claim 9 , further comprising multiple reference line coding using the MPM list.

15. The method according to claim 9 , wherein the intra prediction mode of the above neighbor block is determined to be PLANAR, if there is no intra predicted above neighbor block present, and the intra prediction mode of the left neighbor block is determined to be PLANAR, if there is no intra predicted left neighbor block present.

16. The method according to claim 9 , wherein a top left corner of the left neighbor block is located at (xCb−1, yCb+cbHeight−1) and a top left corner of the above neighbor block is located at (xCb+cbWidth−1, yCb−1), where xCb, yCb, cbHeight and cbWidth denote a location of the top left corner of the current block in a width direction, a location of a top left corner of the current block in a height direction, a height of the current block and a width of the current block, respectively.

17. A decoder or an encoder, comprising:
one or more processors; and
a non-transitory computer-readable storage medium coupled to the one or more processors and storing programming for execution by the one or more processors, wherein the programming, when executed by the one or more processors, configures the encoder or decoder to carry out the method according to claim 1 .

18. A non-transitory computer-readable storage medium coupled to one or more processors and storing programming for execution by the one or more processors, wherein the programming, when executed by the one or more processors, configures an encoder or a decoder to perform following operations:
obtaining an intra prediction mode of a left neighbor block of a current block,
obtaining an intra prediction mode of an above neighbor block of the current block, and
constructing a Most Probable Mode (MPM) list of intra prediction modes for the current block, the MPM list consisting 6 entries of intra prediction modes in the following order:
{PLANAR,ang,2+((ang+61)%64),2+((ang−1)%64), 2+((ang+60)%64),2+((ang)%64)} when at least a first condition is fulfilled, wherein the first condition includes that the intra prediction mode of the left neighbor block and the intra prediction mode of the above neighbor block are the same angular mode, and wherein ang represents the intra prediction mode of the left neighbor block or the intra prediction mode of the above neighbor block.

19. The non-transitory computer-readable storage medium according to claim 18 , wherein the MPM list consists of the 6 entries of intra prediction modes when the first condition and a second condition are fulfilled, wherein the second condition includes that the current block is coded with Intra Sub Partition (ISP) mode.

Assignees

• Huawei Tech Co Ltd

Inventors

• Wang Biao
• Esenlik Semih
• Kotra Anand Meher
• Gao Han
• Chen Jianle

Classifications

• H04N19/176

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

• H04N19/157 Primary

  Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter · CPC title

• H04N19/136

  Incoming video signal characteristics or properties · CPC title

• H04N19/119

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

• H04N19/11 Primary

  among a plurality of spatial predictive coding modes · CPC title