Motion Estimation Apparatus Using Segmented Full-Pel and Refinement Stages
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Solution Overview
Problem
H.264/MPEG-4 AVC video encoders face challenges in real-time applications due to the complexity of the motion estimation process, which can become a bottleneck and result in delays and inefficiencies, especially when calculating difference motion vectors requires knowledge of true motion vectors from neighboring blocks.
Innovation Solution
The motion estimation process is optimized by dividing it into full-pel motion estimation and refinement motion estimation, with full-pel motion estimation operating independently of the main coding loop and using approximated predicted motion vectors to quickly provide candidate motion vectors, allowing refinement to determine final motion vectors with greater computational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full motion estimation is performed within the main coding loop using true motion vectors from neighboring blocks, then measurement precision of motion vectors is improved, but device complexity and processing time increase significantly
Solution Approach 1:
The motion estimation process is divided into two independent stages: a first stage that generates initial motion vector candidates using simplified calculations, and a second stage that refines these candidates. This segmentation allows the complex precision measurement to be applied only to selected candidates rather than all possible motion vectors, reducing overall computational complexity while maintaining accuracy.
Solution Approach 2:
The system performs preliminary motion estimation using approximated motion vectors from previously decoded blocks before entering the main coding loop. This preliminary action generates candidate motion vectors that can be quickly evaluated, eliminating the need to perform full complex calculations for all candidates and reducing the computational burden on the main coding loop.
2Measurement precision
If motion estimation waits for feedback from the main coding loop, then motion vector precision is improved, but processing speed decreases
Solution Approach 1:
The system performs preliminary motion estimation using approximated motion vectors from previously decoded blocks before entering the main coding loop. This preliminary action generates candidate motion vectors that can be quickly evaluated, eliminating the need to perform full complex calculations for all candidates and reducing the computational burden on the main coding loop.
Solution Approach 2:
The motion estimation system uses motion vectors from previously decoded neighboring blocks to generate predictions for current blocks without requiring feedback loops. This self-service approach allows parallel processing and eliminates waiting time, significantly improving processing speed while maintaining acceptable accuracy through the use of historical motion information.
3Manufacturing precision
If difference motion vector calculation uses true motion vectors from neighboring blocks, then encoding precision is improved, but productivity decreases due to computational burden
Solution Approach 1:
The encoding process is segmented into candidate generation and refinement stages. In the candidate generation stage, simplified calculations produce initial motion vector candidates. In the refinement stage, more precise calculations are applied only to selected candidates, maintaining encoding precision while improving overall productivity by avoiding unnecessary complex calculations.
Solution Approach 2:
The system changes the precision parameter dynamically: using lower precision approximated motion vectors for initial candidate generation and higher precision true motion vectors for final encoding decisions. This parameter change allows the system to balance encoding precision and productivity by applying high precision only where necessary.
Data Source
AI summary
The present invention discloses a system and method for performing motion estimation associated with an encoder, e.g., a H.264/MPEG-4 AVC compliant encoder. For example, the method selects a motion vector centering for a current block in a search area of at least one reference picture. The method calculates a matching cost for each of a plurality of candidate motion vectors derived from the search area, and outputs at least one of the plurality of candidate motion vectors based on the matching cost associated with each of the plurality of candidate motion vectors to a main coding loop.