Subblock Temporal Motion Vector Prediction With DV Offsets
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in intra prediction and motion vector prediction, particularly in handling the increasing number of possible directions and redundancy in video data, which affects compression efficiency.
Innovation Solution
The implementation of subblock-based temporal motion vector prediction (SbTMVP) using multiple displacement vector predictors and offsets, which enhances the prediction process by utilizing a base index and displacement vector offset information to reconstruct subblocks based on collocated blocks in a reference picture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional motion vector prediction is used at the block level, then the encoding complexity is low, but the compression efficiency is reduced due to increased data redundancy
Solution Approach 1:
The current block is divided into multiple subblocks, and motion vector prediction is performed independently for each subblock. This segmentation allows for more precise motion compensation by capturing local motion variations within the block, thereby improving compression efficiency without requiring a complete redesign of the overall encoding framework
Solution Approach 2:
Different motion prediction modes and parameters are applied to different subblocks based on their local characteristics. This local quality approach enables the encoder to adapt to varying motion patterns within different regions of the block, improving compression efficiency by reducing data redundancy while maintaining manageable encoding complexity through localized processing
2Measurement precision
If subblock-based motion prediction is implemented, then motion information accuracy is improved, but the data redundancy increases leading to reduced compression efficiency
Solution Approach 1:
The patent applies subblock-based motion prediction selectively rather than uniformly to all blocks. By using flags and mode selection mechanisms, the encoder can apply detailed subblock-level prediction only when necessary (when it provides significant accuracy improvement), while using coarser block-level prediction for other cases, thus balancing motion information accuracy with compression efficiency
Solution Approach 2:
The patent introduces configurable parameters such as subblock size, prediction mode selection, and reference picture indexing that can be adjusted based on content characteristics. These parameter changes allow the system to optimize the trade-off between motion information accuracy and compression efficiency by adapting the prediction granularity and complexity to match the actual motion patterns in the video content
3Productivity
If multiple displacement vector predictors are used with offset, then the coding performance is improved, but the computational complexity increases
Solution Approach 1:
Multiple displacement vector predictors are pre-calculated from neighboring blocks and reference pictures before the actual motion compensation process. This preliminary action allows the encoder to have multiple candidate predictors ready, from which the best one can be selected for each subblock, improving coding performance while managing computational complexity through advance preparation
Solution Approach 2:
The patent employs a feedback mechanism where the encoder evaluates multiple displacement vector predictors and selects the one that provides the best prediction accuracy for each subblock. This feedback-driven selection process ensures that computational resources are focused on generating and evaluating predictors that actually improve coding performance, rather than uniformly processing all possible predictors
Data Source
AI summary
A method and an apparatus are provided. The apparatus includes processing circuitry that receives a coded video bitstream comprising a current picture that includes a current block. The processing circuitry determines, based on a syntax element in the coded video bitstream, that the current block including a plurality of subblocks is coded in a subblock-based temporal motion vector prediction (SbTMVP) mode. The processing circuitry determines a plurality of displacement vector (DV) predictor (DVP) candidates and receives a base index indicating a DVP in the plurality of DVP candidates and a DV offset of the current block. The processing circuitry determines a DV based on the DVP and the DV offset. The DV indicates a block collocated with the current block in a collocated reference picture. The processing circuitry reconstructs a subblock in the plurality of subblocks based on motion information of a corresponding subblock in the collocated block.