Motion Reference Block Selection for Lower-Bitrate Image Encoding
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Solution Overview
Problem
Existing image encoding methods, such as H.264, face challenges in efficiently encoding motion vectors due to high code amounts required for motion information and reference frame numbers, particularly when using multiple reference frames, and have limited motion vector calculation freedom in direct modes.
Innovation Solution
The method selects a motion reference block from already-encoded pixel blocks, identifies an available block with different motion, and encodes selection information using a code table based on the number of available blocks, reducing the code amount by optimizing motion vector allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion compensation is performed using multiple reference frames, then prediction accuracy is improved, but code amount increases due to encoding motion information and reference frame numbers
Solution Approach 1:
The patent extracts only the necessary motion information from multiple reference frames by selecting a single motion reference block, rather than encoding motion vectors from all available reference frames. This selective extraction maintains prediction accuracy while significantly reducing the code amount required for motion information.
Solution Approach 2:
The patent segments the motion compensation process into two stages: first selecting an optimal motion reference block from multiple candidates based on prediction accuracy, then encoding only the motion information from that selected block. This segmentation allows the system to benefit from multiple reference frames without encoding all their motion data.
2Quantity of substance
If direct mode is used to derive motion vector from median of adjacent blocks, then code amount is reduced, but motion vector calculation freedom is limited
Solution Approach 1:
The patent introduces dynamic selection of motion reference blocks based on content characteristics, replacing the static direct mode approach. The system dynamically chooses from multiple motion reference blocks (including spatial and temporal neighbors) according to prediction accuracy, providing adaptability while maintaining efficient coding through selective reference block usage.
3Adaptability or versatility
If one already-encoded block is selected to allocate motion vector, then motion vector calculation freedom is enhanced, but code amount increases due to selection information
Solution Approach 1:
The patent applies partial action by selecting only the most relevant motion reference block(s) from the available candidates based on prediction accuracy, rather than considering all possible blocks. This partial selection approach achieves sufficient motion vector calculation freedom while avoiding the code overhead of transmitting selection information for all candidate blocks.
Data Source
AI summary
According to one embodiment, an image encoding method includes selecting a motion reference block from an already-encoded pixel block. The method includes selecting an available block including different motion information from the motion reference block, and selecting a selection block from the available block. The method includes generating a predicted image of the encoding target block using motion information of the selection block. The method includes encoding a prediction error between the predicted image and an original image. The method includes encoding selection information identifying the selection block by referring to a code table decided according to a number of the available block.