Video Encoding Early Termination Algorithm for Computational Complexity Reduction
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Solution Overview
Problem
Current video compression methods, such as HEVC, face high computational complexity in determining the best motion vector predictor and coding mode due to the evaluation of multiple rate-distortion costs for each candidate, which increases encoding and decoding time without significant improvements in coding efficiency.
Innovation Solution
Implementing an early termination algorithm that reduces the number of rate-distortion cost calculations by skipping unnecessary computations for motion vector predictor candidates, particularly when the first candidate is a zero vector or when the rate-distortion cost exceeds a certain threshold, thereby focusing on the most efficient predictors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple rate-distortion costs are evaluated for each motion vector predictor candidate to determine the best predictor, then coding efficiency is improved, but computational complexity and encoding time increase significantly
Solution Approach 1:
The patent applies partial action by evaluating rate-distortion costs for only a subset of motion vector predictor candidates rather than all candidates. The early termination algorithm stops the evaluation process when a predetermined condition is met, such as when the rate-distortion cost exceeds a threshold or when a sufficient number of candidates have been evaluated. This partial evaluation approach maintains acceptable coding efficiency while significantly reducing the computational burden of evaluating every single candidate.
Solution Approach 2:
The patent implements skipping by bypassing the rate-distortion cost evaluation for certain motion vector predictor candidates under specific conditions. When the early termination condition is triggered, the algorithm skips the remaining candidates and proceeds with encoding using the best predictor found so far. This skipping mechanism eliminates unnecessary computations while preserving the quality of the selected motion vector predictor.
2Measurement precision
If multiple rate-distortion costs are evaluated for each motion vector predictor candidate, then the best predictor can be selected accurately, but encoding time increases by approximately 5%
Solution Approach 1:
The patent applies partial action by performing rate-distortion cost evaluations only for a limited number of motion vector predictor candidates or until a predetermined condition is satisfied. The early termination algorithm monitors the evaluation process and stops when the rate-distortion cost exceeds a threshold or when a maximum number of candidates have been assessed. This approach achieves sufficient predictor selection accuracy while reducing encoding time by avoiding exhaustive evaluation of all candidates.
Solution Approach 2:
The patent implements preliminary action by establishing predetermined conditions and thresholds before the actual encoding process begins. These pre-defined criteria (such as maximum number of candidates to evaluate or threshold values for rate-distortion cost) guide the early termination decision during encoding. By having these conditions prepared in advance, the algorithm can quickly determine when to stop evaluations without complex real-time decision-making, thus reducing encoding time while maintaining selection accuracy.
3Measurement precision
If exhaustive evaluation of motion vector predictor candidates is performed, then decoding accuracy is improved, but decoding time increases by about 3%
Solution Approach 1:
The patent applies the copying principle by having the decoder replicate the same early termination logic and evaluation process that the encoder used. The decoder receives information about which candidates were evaluated and which predictor was selected, and it performs the same partial evaluation to arrive at the identical selection. This copying approach ensures decoding accuracy matches encoding accuracy while avoiding the need for the decoder to perform exhaustive evaluations, thus reducing decoding time.
Data Source
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AI summary
A method of and a device for determining encoding parameters for encoding, into a bitstream, a portion of an image of a video sequence, the image portion being encoded by motion compensation with respect to at least one reference image portion, the encoding parameters for encoding the image portion including a coding mode and a motion information predictor, wherein the coding mode is selected from among at least a first coding mode and a second coding mode and wherein the motion information predictor is selected from a set of motion information predictors which is the same for at least the first and the second coding modes, the selection of the coding mode and the motion information predictor involving comparing costs of encoding the image portion using the motion information predictors of the set in the two coding modes, the method comprising or the device comprising means for: omitting, for at least one said motion information predictor of the set, computing of such a cost for at least one of said first and second coding modes. Consequently encoding time and complexity may be reduced and encoding performance may be improved.