Motion Vector Coding Simplifications for Video Compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video coding systems face inefficiencies due to significant signaling overhead in motion vector signaling, particularly when high precision motion vectors are required for accurate prediction, which increases complexity and bitstream length.
Innovation Solution
The proposed solution involves constraining motion vectors to integer precision and using a simplified coding structure, where motion vectors are signaled directly instead of motion vector differences, and employing techniques like temporal interpolation prediction to align frames temporally, reducing the need for sub-pel motion compensation and complex interpolation filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high precision motion vectors are used for accurate prediction, then prediction accuracy is improved, but signaling overhead increases
Solution Approach 1:
The motion vector is segmented into two parts: a base integer vector and a fractional offset. The integer part is coded using conventional methods while the fractional part is represented with simplified precision constraints, reducing overall signaling overhead while maintaining prediction accuracy for high-motion content
Solution Approach 2:
The patent changes the precision parameter of motion vectors from sub-pixel level to integer level in certain conditions. By adjusting the motion vector precision parameter dynamically based on content characteristics, the system reduces signaling overhead while maintaining adequate prediction accuracy
2Measurement precision
If sub-pel motion compensation and complex interpolation filters are used, then prediction accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent uses simpler, computationally cheaper integer-based motion compensation instead of expensive sub-pel interpolation filters. While sub-pel methods provide marginally better accuracy, the integer-based approach achieves sufficient prediction accuracy with significantly reduced computational complexity, especially for high-motion content
Solution Approach 2:
The patent changes the motion compensation parameter from sub-pixel precision to integer precision, and disables complex interpolation filters. This parameter change reduces computational complexity while maintaining adequate prediction accuracy through alternative methods such as temporal interpolation prediction
3Measurement precision
If motion vectors are coded with high precision, then prediction accuracy is improved, but bitstream length increases
Solution Approach 1:
The patent changes the precision parameter of motion vector coding from sub-pixel to integer level, reducing the number of bits required to represent motion vectors. This parameter change directly reduces bitstream length while maintaining adequate prediction accuracy through the use of temporal interpolation prediction and other compensation methods
4Measurement precision
If complex interpolation filters are applied, then prediction accuracy is improved, but processing time increases
Solution Approach 1:
The patent replaces complex interpolation filters with simpler integer-based motion compensation methods. This substitution reduces processing time significantly while maintaining adequate prediction accuracy, particularly for high-motion content where temporal interpolation prediction is employed
Data Source
AI summary
Techniques are disclosed for improved video coding with virtual reference frames. A motion vector for prediction of a pixel block from a reference may be constrained based on the reference. In as aspect, if the reference is a temporally interpolated virtual reference frame with corresponding time close to the time of the current pixel block, the motion vector for prediction may be constrained magnitude and/or precision. In another aspect, a bitstream syntax for encoding the constrained motion vector may also be constrained. In this manner, the techniques proposed herein contribute to improved coding efficiencies.