Non-MPM mode coding for intra prediction in video coding

Patent metadata

Field	Value
Publication number	US-10764577-B2
Application number	US-201916664601-A
Country	US
Kind code	B2
Filing date	Oct 25, 2019
Priority date	Oct 25, 2018
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for performing intra coding predictions. An intra-coding process applied to pixels in a frame of media is determined. The intra-coding process is determined whether to corresponding to at least one of most probable modes. In response to determining the intra-coding process does not correspond to the at least one of the most probable modes, four angular prediction modes are extracted from a list of prediction modes. A set of candidates based on the four angular prediction modes are determined. A pre-defined order of the set of candidates is determined, wherein each candidate mode of the set of candidate modes is included in a ranked order and signaled with a particular fixed length coding, and wherein a length of the particular fixed length coding increases based on the pre-defined order of the set of candidate modes.

First claim

What is claimed is:

1. A computer-implemented method, comprising:
determining, by one or more processors, an intra-coding process applied to pixels in a frame of media;
determining, by the one or more processors, whether the intra-coding process corresponds to at least one of most probable modes;
in response to determining the intra-coding process does not correspond to the at least one of the most probable modes, extracting, by the one or more processors, four angular prediction modes from a list of prediction modes;
determining, by the one or more processors, a set of candidate modes based on the four angular prediction modes; and
determining, by the one or more processors, a pre-defined order of the set of candidate modes, wherein each candidate mode of the set of candidate modes is included in a ranked order and signaled with a particular fixed length coding, and wherein a length of the particular fixed length coding increases based on the pre-defined order of the set of candidate modes.

2. The computer-implemented method of claim 1 , wherein the four angular prediction modes correspond to angular directions from a list of directional prediction modes.

3. The computer-implemented method of claim 1 , wherein determining the pre-defined order of the set of candidate modes further comprises:
generating, by the one or more processors, a statistical matrix for the pre-defined order in response to determining the intra-coding process does not correspond to the at least one of the most probable modes.

4. The computer-implemented method of claim 3 , wherein the generated statistical matrix further comprises:
applying, by the one or more processors, the candidate mode to each column of the statistical matrix;
applying, by the one or more processors, a different intra prediction mode to each row of the statistical matrix, wherein the different intra prediction mode corresponds to one of sixty one non-most probable modes; and
applying, by the one or more processors, a number of times each of the candidate modes corresponds to a current mode for previous frames of media to each cell in the statistical matrix.

5. The computer-implemented method of claim 4 , wherein determining the pre-defined order of the set of candidate modes comprises:
summing, by the one or more processors, the number of times each of the candidate modes corresponds to the current mode for each candidate mode; and
sorting, by the one or more processors, the candidate modes based on most occurring candidate mode to a least occurring candidate mode.

6. The computer-implemented method of claim 1 , wherein determining the pre-defined order of the set of candidate modes comprises:
signaling, by the one or more processors, each candidate mode of the set of candidate modes in the ranked order with the particular fixed length coding to a decoder for decoding the frame of media.

7. The computer-implemented method of claim 1 , wherein the at least one of the most probable modes comprise a DC mode and a planar mode.

8. The computer-implemented method of claim 1 , wherein the length of the particular fixed length coding increases based on the pre-defined order of the set of candidate modes and comprises four bits, five bits, and six bits.

9. A system comprising one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising:
determining, by one or more processors, an intra-coding process applied to pixels in a frame of media;
determining, by the one or more processors, whether the intra-coding process corresponds to at least one of most probable modes;
in response to determining the intra-coding process does not correspond to the at least one of the most probable modes, extracting, by the one or more processors, four angular prediction modes from a list of prediction modes;
determining, by the one or more processors, a set of candidate modes based on the four angular prediction modes; and
determining, by the one or more processors, a pre-defined order of the set of candidate modes, wherein each candidate mode of the set of candidate modes is included in a ranked order and signaled with a particular fixed length coding, and wherein a length of the particular fixed length coding increases based on the pre-defined order of the set of candidate modes.

10. The system of claim 9 , wherein the four angular prediction modes correspond to angular directions from a list of directional prediction modes.

11. The system of claim 9 , wherein determining the pre-defined order of the set of candidate modes further comprises:
generating, by the one or more processors, a statistical matrix for the pre-defined order in response to determining the intra-coding process does not correspond to the at least one of the most probable modes.

12. The system of claim 11 , wherein the generated statistical matrix further comprises:
applying, by the one or more processors, the candidate mode to each column of the statistical matrix;
applying, by the one or more processors, a different intra prediction mode to each row of the statistical matrix, wherein the different intra prediction mode corresponds to one of sixty one non-most probable modes; and
applying, by the one or more processors, a number of times each of the candidate modes corresponds to a current mode for previous frames of media to each cell in the statistical matrix.

13. The system of claim 12 , wherein determining the pre-defined order of the set of candidate modes comprises:
summing, by the one or more processors, the number of times each of the candidate modes corresponds to the current mode for each candidate mode; and
sorting, by the one or more processors, the candidate modes based on most occurring candidate mode to a least occurring candidate mode.

14. The system of claim 9 , wherein determining the pre-defined order of the set of candidate modes signaling each candidate mode of the set of candidate modes in a ranked order with a particular fixed length coding comprises:
signaling, by the one or more processors, each candidate mode of the set of candidate modes in the ranked order with the particular fixed length coding to a decoder for decoding the frame of media.

15. The system of claim 9 , wherein the at least one of the most probable modes comprise a DC mode and a planar mode.

16. The system of claim 9 , wherein the length of the particular fixed length coding increases based on the pre-defined order of the set of candidate modes and comprises four bits, five bits, and six bits.

17. One or more non-transitory computer-readable media comprising instructions stored thereon that are executable by one or more processing devices and upon such execution cause the one or more processing devices to perform operations comprising:
determining, by one or more processors, an intra-coding process applied to pixels in a frame of media;
determining, by the one or more processors, whether the intra-coding process corresponds to at least one of most probable modes;
in response to determining the intra-coding process does not correspond to the at least one of the most probable modes, extracting, by the one or more processors, four angular prediction modes from a list of prediction modes;
determining, by the one or more processors, a set of candidate modes based on the four angular prediction modes; and
determining, by the one or more processors, a pre-defined order of the set of candidate modes, wherein each candidate mode of

Assignees

• Futurewei Technologies Inc
• Univ Santa Clara

Inventors

• Jiang Minqiang
• Kanchan Taru
• Zheng Jianhua
• Ling Nam
• Zhang Chen-Xiong

Classifications

• H04N19/159

  Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction · CPC title

• H04N19/182

  the unit being a pixel · CPC title

• H04N19/593

  involving spatial prediction techniques · CPC title

• H04N19/91

  Entropy coding, e.g. variable length coding [VLC] or arithmetic coding · CPC title

• H04N19/463 Primary

  by compressing encoding parameters before transmission · CPC title