Sub-block Inter Prediction for Video Coding Precision

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Solution Overview

Problem

Current video coding standards face challenges in efficiently managing bandwidth demand for digital video due to limitations in motion vector prediction and coding methods, particularly in sub-block based inter prediction, which affects the quality of decompressed video.

Innovation Solution

The implementation of sub-block based inter prediction methods, including temporal motion vector prediction (TMVP) and affine motion compensation, to enhance the construction of merge candidate lists and motion vector prediction processes, allowing for more efficient coding and decoding of video frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sub-block based inter prediction methods are implemented, then motion vector prediction precision is improved, but device complexity increases

Engineering Contradiction:

Improvemotion vector prediction precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The current block is divided into multiple sub-blocks, and each sub-block independently constructs merge candidate lists and performs motion vector prediction. This segmentation allows for more precise local motion representation while managing complexity through modular processing of smaller units.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different merge candidate lists are constructed for different sub-blocks based on their local characteristics. Each sub-block has its own motion vector prediction process, allowing the system to adapt to local motion variations and improve prediction precision where needed without uniformly increasing complexity across the entire block.

Inventive Principle:

Principle #3Local quality

2Productivity

If more merge candidates are added to sub-block based merge candidate list, then coding efficiency is improved, but loss of information increases

Engineering Contradiction:

Improvecoding efficiencyVSAvoidloss of information

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

Merge candidates are pre-constructed and stored in merge candidate lists before the actual coding process. This preliminary construction allows the decoder to reconstruct the same candidate lists without transmitting all candidate information, reducing bitstream overhead while maintaining coding efficiency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Motion information from neighboring blocks and temporal references is copied to create merge candidates. Instead of transmitting redundant motion information for each candidate, the system uses indexing to reference these copied candidates, improving coding efficiency while minimizing information loss through selective transmission of only necessary indices.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS11871025B2Motion precision in sub-block based inter prediction

Publication Date: 2024.01.09 DOUYIN VISION CO LTD

AI summary

Devices, systems and methods for digital video coding, which include sub-block based inter prediction methods, are described. An exemplary method for video processing includes determining, for a conversion between a current block of video and a bitstream representation of the video, a maximum number of candidates in a sub-block based merge candidate list and/or whether to add sub-block based temporal motion vector prediction (SbTMVP) candidates to the sub-block based merge candidate list based on whether temporal motion vector prediction (TMVP) is enabled for use during the conversion or whether a current picture referencing (CPR) coding mode is used for the conversion, and performing, based on the determining, the conversion.