Inter Prediction Using Temporal Offset Vectors for Subblock Motion
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Solution Overview
Problem
Existing video coding technologies face challenges in reducing implementation complexity while improving the accuracy of motion vector prediction for inter prediction in video coding.
Innovation Solution
The method involves determining a temporal offset vector based on spatially neighboring blocks to obtain motion vectors for subblocks, using preset motion vectors when unavailable, and employing various strategies to reduce complexity, including zero motion vectors and different reference frame lists based on prediction types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion vector is obtained based on subblock with temporal offset vector, then motion vector prediction accuracy is improved, but implementation complexity increases
Solution Approach 1:
The current block is divided into multiple subblocks, and motion vector prediction is performed separately for each subblock. This segmentation allows for more precise motion compensation at the subblock level while managing complexity through localized processing rather than global processing of the entire block.
Solution Approach 2:
The patent applies motion vector prediction to only certain subblocks where it provides benefit, rather than uniformly to all blocks. The temporal offset vector is used selectively based on availability of reference block motion vectors, avoiding unnecessary computation where simple block-level prediction suffices.
2Measurement precision
If temporal offset vector is derived from spatially neighboring blocks, then prediction accuracy is improved, but computational complexity increases
Solution Approach 1:
Motion vectors of spatially neighboring blocks are obtained and stored in advance before being used to derive temporal offset vectors. This preliminary preparation allows the temporal offset calculation to proceed efficiently without repeated searches or complex computations during the main prediction process.
Solution Approach 2:
The temporal offset vector acts as an intermediary that bridges spatial neighboring block motion information and the current subblock motion vector prediction. It translates spatial correlation into temporal prediction by adding the offset to reference frame motion vectors, simplifying the overall prediction mechanism.
3Device complexity
If preset motion vector is used when collocated subblock motion vector is unavailable, then implementation complexity is reduced, but prediction accuracy may deteriorate
Solution Approach 1:
The patent prepares fallback options (preset motion vectors) in advance for cases where temporal offset vector derivation fails or is unavailable. This cushioning ensures that prediction can always proceed without interruption, maintaining system reliability while accepting reduced accuracy only when necessary.
Solution Approach 2:
Preset motion vectors serve as simple, computationally inexpensive fallback solutions that are used only when more accurate methods are unavailable. These disposable vectors provide adequate prediction in limited cases without the computational overhead of complex derivation processes.
Data Source
AI summary
This application discloses an inter prediction method, where a to-be-processed block includes one or more subblocks, and the method includes: determining a temporal offset vector of the to-be-processed block based on a spatially neighboring block of the to-be-processed block, where the temporal offset vector is used to determine a collocated subblock of the subblock of the to-be-processed block; and determining a motion vector of the subblock of the to-be-processed block based on a motion vector of the collocated subblock, where the motion vector of the subblock of the to-be-processed block is obtained based on a first preset motion vector when the motion vector of the collocated subblock is unavailable. This application can improve prediction accuracy in coding and increase coding efficiency.