Adaptive Motion Vector Precision Selection in Video Encoding
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Solution Overview
Problem
Existing video codec standards face challenges in effectively selecting motion vector precision during encoding, leading to suboptimal rate-distortion performance and computational efficiency, particularly in scenarios where integer-sample and fractional-sample MV precisions are not chosen appropriately.
Innovation Solution
A video encoder determines motion vector precision by identifying the prevalence of fractional-sample MV values, performing rate-distortion analysis biased towards integer-sample precision, or collecting information to select between integer-sample and fractional-sample MV precisions, allowing for adaptive selection based on the video content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fractional-sample MV precision is used, then motion estimation accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent implements dynamic selection of MV precision (integer or fractional) based on content characteristics and encoding conditions. The encoder adaptively switches between integer-sample and fractional-sample precision modes, allowing the system to optimize between accuracy and complexity in real-time rather than using a fixed precision level throughout encoding.
Solution Approach 2:
The patent changes the precision parameter of motion vectors from fixed to variable. By introducing a precision selection mechanism that can switch between integer-sample and fractional-sample precision, the system dynamically adjusts this critical parameter based on content complexity, motion characteristics, and rate-distortion trade-offs.
2Reliability
If adaptive MV precision selection is implemented, then rate-distortion performance is improved, but encoding complexity increases
Solution Approach 1:
The patent performs preliminary analysis of content characteristics and motion patterns before finalizing MV precision selection. By pre-evaluating factors such as content type, motion complexity, and potential rate-distortion benefits, the encoder makes informed precision decisions earlier in the encoding process, reducing the need for extensive trial-and-error optimization.
Solution Approach 2:
The patent incorporates feedback mechanisms where encoding results from preliminary precision selections are evaluated, and this information feeds back into subsequent precision decisions. The system uses rate-distortion metrics and encoding performance feedback to continuously refine MV precision selection, improving overall rate-distortion performance while managing complexity through learned patterns.
3Productivity
If integer-sample MV precision is used, then computational efficiency is improved, but motion compensation accuracy deteriorates
Solution Approach 1:
The patent applies different MV precision levels to different regions or blocks within the video content based on local characteristics. High-motion or complex-content regions receive fractional-sample precision for improved accuracy, while low-motion or simple-content regions use integer-sample precision for computational efficiency. This local adaptation optimizes the balance between accuracy and efficiency.
Solution Approach 2:
The patent segments the video content into different regions with different motion characteristics and applies appropriate MV precision to each segment. By dividing the content and analyzing motion patterns in each segment separately, the system can selectively apply fractional-sample precision only where necessary, maintaining overall accuracy while improving computational efficiency through targeted application.
Data Source
AI summary
Approaches to selection of motion vector (“MV”) precision during video encoding are presented. These approaches can facilitate compression that is effective in terms of rate-distortion performance and/or computational efficiency. For example, a video encoder determines an MV precision for a unit of video from among multiple MV precisions, which include one or more fractional-sample MV precisions and integer-sample MV precision. The video encoder can identify a set of MV values having a fractional-sample MV precision, then select the MV precision for the unit based at least in part on prevalence of MV values (within the set) having a fractional part of zero. Or, the video encoder can perform rate-distortion analysis, where the rate-distortion analysis is biased towards the integer-sample MV precision. Or, the video encoder can collect information about the video and select the MV precision for the unit based at least in part on the collected information.