Motion Vector Coding for Multi-Hypothesis Video Prediction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multiple hypothesis inter prediction in video coding requires significant side information transmission, which increases overhead and may not fully realize the distortion benefits, especially in low bitrate applications, limiting its potential.
Innovation Solution
The method involves predicting and coding motion vectors by representing differences between actual and predicted motion vectors, reducing the need to transmit all motion vectors explicitly, and using these residuals to reconstruct motion vectors at the decoding end, thereby minimizing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple hypothesis inter prediction is used to improve prediction quality, then distortion is reduced, but side information overhead increases
Solution Approach 1:
The patent merges the coding of motion vectors for multiple hypotheses by predicting one motion vector from another and only coding the residual difference. This combines what would otherwise be separate independent coding operations into a single integrated process, reducing total overhead while maintaining prediction quality
Solution Approach 2:
The patent changes the parameter representation from coding absolute motion vectors to coding motion vector differences (residuals). This parameter transformation exploits the correlation between hypotheses to reduce the number of bits required, directly addressing the overhead problem while preserving the distortion benefits
2Measurement precision
If multiple hypothesis inter prediction is used to reduce distortion, then prediction accuracy improves, but bitrate increases
Solution Approach 1:
The patent transforms the representation parameters from absolute motion vectors to differential motion vector residuals. This parameter change exploits statistical correlations to achieve more efficient entropy coding, reducing bitrate while maintaining the multiple hypothesis prediction accuracy benefits
3Ease of operation
If independent coding of side information for each predictor is used, then coding simplicity is maintained, but potential of multiple hypothesis inter prediction is limited
Solution Approach 1:
The patent merges previously independent coding operations into a unified differential coding process. While the operation becomes slightly more complex (requiring prediction and residual calculation), the overall coding efficiency improves significantly through reduced bitrate, resolving the contradiction between simplicity and efficiency
Data Source
AI summary
The present disclosure describes techniques for efficient coding of motion vectors developed for multi-hypothesis coding applications. According to these techniques, when coding hypotheses are developed, each having a motion vector identifying a source of prediction for a current pixel block, a motion vector for a first one of the coding hypotheses may be predicted from the motion vector of a second coding hypothesis. The first motion vector may be represented by coding a motion vector residual, which represents a difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis, and outputting the coded residual to a channel. In another embodiment, a motion vector residual may be generated for a motion vector of a first coding hypothesis, and the first motion vector and the motion vector residual may be used to predict a second motion vector and a predicted motion vector residual. The second hypothesis's motion vector may be coded as a difference between the motion vector, the predicted second motion vector, and the predicted motion vector residual. In a further embodiment, a single motion vector residual may be output for the motion vectors of two coding hypotheses representing a difference between the motion vector of one of the hypotheses and a predicted motion vector for that hypothesis.