Subblock Motion Vector Prediction Using Displacement Offset
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding technologies face challenges in efficiently predicting motion vectors for subblocks within a current picture, particularly in advanced motion vector prediction modes, which affects compression efficiency and bitstream size.
Innovation Solution
The implementation of a subblock-based temporal motion vector prediction (SbTMVP) mode that uses a displacement vector (DV) offset, indicated by DV offset information, to determine an updated DV for a current block, allowing for more precise motion information derivation from corresponding subblocks in a collocated reference picture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If subblock-based temporal motion vector prediction is implemented with DV offset, then motion vector prediction precision is improved, but computational complexity increases
Solution Approach 1:
The current block is divided into multiple subblocks, and motion vector prediction is performed independently for each subblock using subblock-based temporal motion vector prediction. This segmentation allows for more precise motion compensation by capturing local motion variations within different regions of the block, directly improving motion vector prediction precision while managing computational complexity through localized processing.
Solution Approach 2:
Different motion characteristics are applied to different subblocks within the same block based on their local motion properties. Each subblock can have its own motion vector derived from corresponding subblocks in reference pictures, allowing the system to adapt to local motion variations and improve prediction accuracy without requiring uniform high-complexity processing across the entire block.
2Productivity
If subblock-based temporal motion vector prediction with DV offset is used, then coding efficiency is improved, but bitstream size increases
Solution Approach 1:
The displacement vector offset information is derived and prepared in advance during the encoding process. By pre-calculating the offset based on motion information from collocated blocks in reference pictures, the system reduces the amount of data that needs to be transmitted in the bitstream, as the offset can be inferred or requires fewer bits to encode compared to transmitting full motion vectors for each subblock.
Data Source
AI summary
Aspects of the disclosure provide a method and an apparatus including processing circuitry that determines, based on a syntax element in a coded video bitstream, that a current block including a plurality of subblocks is coded in a subblock-based temporal motion vector prediction (SbTMVP) mode. Motion vector offset (MVO) information indicating an MVO is received. The MVO indicates a motion offset of a displacement vector (DV) used to adjust a location of a collocated block in a collocated reference picture. An updated DV of the current block is determined based on the DV and the MVO. SbTMVP information of a respective subblock in the plurality of subblocks is derived based on motion information of a corresponding subblock in the collocated block indicated by the updated DV. The plurality of subblocks in the SbTMVP mode is reconstructed based on the SbTMVP information of the subblock in the plurality of subblocks.