Motion Vector Derivation via Reference Index Segmentation
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Solution Overview
Problem
Conventional motion vector coding methods often derive motion vector predictors that are irrelevant to the original motion of an object, leading to reduced compression efficiency and inaccurate motion vector derivation.
Innovation Solution
A moving picture decoding device and method that derive a motion vector for a prediction block by selecting candidate blocks from neighboring blocks based on identical motion vector numbers and reference indices, ensuring that the motion vector predictor accurately reflects the original motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a motion vector predictor is derived from neighboring blocks using conventional methods, then the compression efficiency is improved, but the accuracy of motion vector derivation deteriorates when the motion of objects differs from the reference block
Solution Approach 1:
The patent applies local quality by differentiating the selection criteria for candidate blocks based on their spatial relationship to the prediction block. Specifically, it distinguishes between blocks in the left/right direction (using motion vector numbers) and blocks in the up/down direction (using reference picture indices), allowing each region to contribute its motion vector predictor only when locally relevant, thus improving accuracy while maintaining compression efficiency
Solution Approach 2:
The patent segments the neighboring blocks into different groups based on their positional relationships (left, right, up, down) and applies different selection criteria to each group. This segmentation allows the motion vector predictor to be derived more accurately by considering only appropriate reference blocks for each directional context, resolving the contradiction between compression efficiency and derivation accuracy
2Device complexity
If motion vector predictors are derived without considering reference picture indices, then the device complexity is reduced, but the reliability of motion compensation prediction deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-establishing the selection criteria for candidate blocks based on their spatial position and reference picture index before the actual motion vector derivation. The motion information derivation unit is configured to automatically apply these pre-defined criteria, which simplifies the overall process while ensuring reliable prediction through systematic consideration of reference picture indices
Data Source
AI summary
A motion vector decoding unit derives a motion vector of a prediction block subject to decoding on the basis of a motion vector of a candidate block included in candidate blocks selected from neighboring blocks. The motion compensation prediction unit performs motion compensation prediction using the derived motion vector. In case a motion vector number of a first block and a motion vector number of a second block are identical with each other, the motion vector decoding unit determines whether or not to set the second block as a candidate block in accordance with whether or not a reference index indicating a reference picture that the motion vector of the first block refers to and a reference index indicating a reference picture that the motion vector of the second block refers to are identical with each other.