Granted Patent B2

US 12,634,468 · App. 18/803,154 · Granted May 19, 2026

Inventors: Han Gao (Palo Alto, CA); Xin Zhao (Palo Alto, CA); Liang Zhao (Palo Alto, CA); Jing Ye (Palo Alto, CA); Madhu Peringassery Krishnan (Palo Alto, CA); Tianqi Liu (Palo Alto, CA); Yushin Cho (Palo Alto, CA); Shan Liu (Palo Alto, CA)

Assignee: TENCENT AMERICA LLC

H04N19/137H04N19/105H04N19/172H04N19/176

Abstract

Claims (47)

1 . A method of video decoding performed at a computing system having memory and one or more processors, the method comprising:

receiving a video bitstream comprising a plurality of blocks;

deriving a set of motion vectors for a current block of the plurality of blocks, the current block being within a current frame;

identifying two or more reference pictures for the current block, the two or more reference pictures having different respective temporal distances to the current frame;

when the different respective temporal distances are less than or equal to a threshold value, deriving a set of refined motion vectors for the current block using motion vector information from the two or more reference pictures, including:

obtaining a scale factor that corresponds to a ratio of the different respective temporal distances;

applying the scale factor to the motion vector information from the two or more reference pictures; and

reconstructing the current block based on the derived set of refined motion vectors; and

when a respective temporal distance is greater than the threshold value, reconstructing the current block based on the set of motion vectors without deriving the set of refined motion vectors.

2 . The method of claim 1 , wherein the scale factor is applied to motion vector information from a closer reference picture of the two or more reference pictures.

3 . The method of claim 1 , wherein the scale factor is applied to motion vector information from a further reference picture of the two or more reference pictures.

4 . The method of claim 1 , wherein the scale factor is obtained from a lookup table.

5 . The method of claim 1 , wherein the scale factor is obtained from an equation by inputting the different respective distances.

6 . The method of claim 1 , wherein applying the scale factor comprises multiplying the scale factor with a first MVD corresponding to a closer reference picture of the two or more reference pictures to generate a second MVD corresponding to a further reference picture of the two or more reference pictures.

7 . The method of claim 1 , wherein pre-fetching areas for the two or more reference pictures are based on the scale factor.

8 . The method of claim 7 , wherein a first pre-fetching area for a further reference picture is larger than a second pre-fetching area for a closer reference picture.

9 . The method of claim 1 , wherein the scale factor is based on coded information.

10 . The method of claim 1 , wherein each reference picture of the two or more reference pictures has a same pre-fetching area.

11 . The method of claim 1 , wherein the two or more reference pictures are on a same side of the current frame.

12 . The method of claim 1 , wherein the two or more reference pictures corresponds to different temporal levels.

13 . A computing system, comprising:

control circuitry;

memory; and

one or more sets of instructions stored in the memory and configured for execution by the control circuitry, the one or more sets of instructions comprising instructions for:

receiving video data comprising a plurality of blocks;

identifying a set of motion vectors for a current block of the plurality of blocks, the current block being within a current frame;

identifying two or more reference pictures for the current block, the two or more reference pictures having different respective temporal distances to the current frame;

when the different respective temporal distances are less than or equal to a threshold value, identifying a set of refined motion vectors for the current block using motion vector information from the two or more reference pictures, including:

obtaining a scale factor that corresponds to a ratio of the different respective temporal distances;

applying the scale factor to the motion vector information from the two or more reference pictures; and

encoding the current block based on the set of refined motion vectors; and

when a respective temporal distance is greater than the threshold value, encoding the current block based on the set of motion vectors without deriving the set of refined motion vectors.

14 . The computing system of claim 13 , wherein the scale factor is obtained from a lookup table.

15 . The computing system of claim 13 , wherein the scale factor is obtained from an equation by inputting the different respective distances.

16 . The computing system of claim 13 , wherein pre-fetching areas for the two or more reference pictures are based on the scale factor.

17 . The computing system of claim 13 , wherein each reference picture of the two or more reference pictures has a same pre-fetching area.

18 . The computing system of claim 13 , wherein the two or more reference pictures are on a same side of the current frame.

19 . The computing system of claim 13 , wherein the scale factor is restricted to integer values.

20 . A non-transitory computer-readable storage medium storing a video bitstream that is generated by a video encoding method, the video bitstream comprising:

coded information for a plurality of blocks of video data, including a current block within a current frame, the current block encoded based on a set of refined motion vectors; and

wherein the video encoding method comprises:

identifying a set of motion vectors for the current block;

identifying two or more reference pictures for the current block, the two or more reference pictures having different respective temporal distances to the current frame;

when the different respective temporal distances are less than or equal to a threshold value, identifying the set of refined motion vectors for the current block using motion vector information from the two or more reference pictures, including:

obtaining a scale factor that corresponds to a ratio of the different respective temporal distances; and

applying the scale factor to the motion vector information from the two or more reference pictures; and

encoding the current block based on the set of refined motion vectors.

Assignments (1)

Continuity (2)

References Cited (15)