Decoder-side motion vector restoration for video coding

Patent metadata

Field	Value
Publication number	US-2018192071-A1
Application number	US-201815861476-A
Country	US
Kind code	A1
Filing date	Jan 3, 2018
Priority date	Jan 5, 2017
Publication date	Jul 5, 2018
Grant date	—

Abstract

The techniques described herein relate to methods, apparatus, and computer readable media configured to determine motion vectors. The techniques relate to both encoders and decoders. For example, a decoder receives compressed video data related to a set of frames. The decoder calculates, using a decoder-side predictor refinement technique, a new motion vector for a current frame from the set of frames, wherein the new motion vector estimates motion for the current frame based on one or more reference frames. The calculation includes retrieving a first motion vector associated with the current frame, executing a first portion of the decoding process using the first motion vector, retrieving a second motion vector associated with the current frame that is different than the first motion vector, and executing a second portion of the decoding process using the second motion vector.

First claim

What is claimed is:

1 . A decoding method for decoding video data, the method comprising:
receiving compressed video data related to a set of frames; and calculating, using a decoder-side predictor refinement technique, a new motion vector for a current frame from the set of frames, wherein the new motion vector estimates motion for the current frame based on one or more reference frames, comprising:
retrieving a first motion vector associated with the current frame;
executing a first portion of a decoding process using the first motion vector;
retrieving a second motion vector associated with the current frame that is different than the first motion vector; and
executing a second portion of the decoding process using the second motion vector.

2 . The decoding method of claim 1 , wherein:
the first motion vector comprises an unrefined motion vector; the second motion vector comprises a refined motion vector, wherein the refined MV is refined using a decoder-side predictor refinement technique; the first portion of the decoding process comprises a parsing portion, a motion vector derivation portion, or both; and the second portion of the decoding process comprises a reconstruction portion.

3 . The decoding method of claim 1 , further comprising:
retrieving a third motion vector associated with a second frame, wherein the third motion vector is a refined motion vector; executing the first portion of the decoding process using the first motion vector and the third motion vector; and executing the second portion of the decoding process using the second motion vector and the third motion vector.

4 . The decoding method of claim 3 , wherein executing the first portion of the decoding process comprises executing a motion vector derivation portion using the first motion vector and the third motion vector, wherein the motion vector derivation portion comprises motion vector prediction derivation, merge candidate derivation, or both.

5 . The decoding method of claim 4 , wherein executing the first portion of the decoding process comprises referring to the first motion vector as a decoded motion vector of the current frame.

6 . The decoding method of claim 3 , further comprising using the second motion vector and the third motion vector to perform motion compensation, overlapped block motion compensation, deblocking, or any combination thereof.

7 . The decoding method of claim 1 , further comprising:
determining a coding tree unit constraint is not applied to the compressed video data; and retrieving the first motion vector associated with the current frame comprises retrieving:
an unrefined motion vector of the current frame; and
a refined motion vector associated with a second frame.

8 . The decoding method of claim 1 , wherein retrieving the first motion vector associated with the current frame comprises retrieving:
an unrefined motion vector of a current coding tree unit row; a refined motion vector of an upper coding tree unit row, other tile, or other slice; and a refined motion vector associated with a second frame.

9 . A decoding method for decoding video data, the method comprising:
receiving compressed video data related to a set of frames; and calculating, using a decoder-side predictor refinement technique, a new motion vector for a current frame from the set of frames, wherein the new motion vector estimates motion for the current frame based on one or more reference frames, comprising:
receiving a signal indicative of a starting candidate index for a starting motion vector candidate list;
determining a first motion vector candidate in the starting motion vector candidate list and a second motion vector candidate comprise a difference that is below a predetermined threshold;
removing the second motion vector candidate from the starting motion vector candidate list, not adding the second motion vector candidate to the starting motion vector candidate list, or both; and
calculating the new motion vector based on the candidate list and the starting candidate index.

10 . The decoding method of claim 9 , further comprising:
analyzing a new motion vector candidate, the motion vector candidate comprising a motion vector pair; determining, based on the analysis, that the motion vector pair is along a same motion trajectory; and adding the motion vector pair to the starting motion vector candidate list.

11 . The decoding method of claim 9 , further comprising:
analyzing a new motion vector candidate, the motion vector candidate comprising a motion vector pair; determining, based on the analysis, that the motion vector pair is not along a same motion trajectory; separating the motion vector pair into two new candidate motion vector pairs; and adding the two candidate motion vectors to the starting motion vector candidate list.

12 . The decoding method of claim 11 , wherein separating comprises:
adding the first motion vector of the motion vector pair to a first of the two new candidate motion vector pairs; filling the first of the two new candidate motion vector pairs with a mirrored motion vector of the first motion vector; adding the second motion vector of the motion vector pair to a second of the two new candidate motion vector pairs; and filling the second of the two new candidate motion vector pairs with a mirrored motion vector of the second motion vector.

13 . An encoding method for encoding video data, the method comprising:
calculating compressed video data related to a set of frames, comprising calculating a new motion vector for a current frame from the set of frames, wherein the new motion vector estimates motion for the current frame based on one or more reference frames, comprising:
calculating a first motion vector associated with the current frame;
executing a first portion of the encoding process using the first motion vector;
calculating a second motion vector associated with the current frame that is different than the first motion vector; and
executing a second portion of the encoding process using the second motion vector.

14 . The encoding method of claim 13 , wherein:
calculating the first motion vector comprises calculating an unrefined motion vector, an unrefined motion vector set, or both; and executing the first portion of the encoding process comprises executing a syntax encoding portion, a motion vector derivation portion, a motion vector prediction derivation portion, or some combination thereof.

15 . The encoding method of claim 14 , wherein executing the motion vector prediction derivation portion comprises generating a merge candidate list, generating an advanced motion vector prediction candidate list, or both.

16 . The encoding method of claim 14 , further comprising performing motion vector encoding, motion vector prediction generation, or both, using the unrefined motion vector, the unrefined motion vector set, or both, such that the unrefined motion vector, the unrefined motion vector set, or both are not refined using a decoder-side motion vector refinement tool.

17 . The encoding method of claim 13 , wherein:
calculating the second motion vector comprises calculating a refined motion vector, wherein the refined motion vector is calculated using an encoder-side refinement technique; storing the refined motion vector in a motion vector buffer set; and executing the second portion of the encoding process comprises executing a motion compensation portion, an overlapped block motion compensation portion, a deblocking portion, or some combin

Assignees

• Mediatek Inc

Inventors

• Chuang Tzu-Der
• Chen Ching-Yeh

Classifications

• H04N19/44 Primary

  Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder · CPC title

• H04N19/52

  by predictive encoding · CPC title

• H04N19/577 Primary

  Motion compensation with bidirectional frame interpolation, i.e. using B-pictures · CPC title

• H04N19/96

  Tree coding, e.g. quad-tree coding · CPC title

• H04N19/517

  by encoding · CPC title