Bi-prediction Motion Vector Predictor Calculation
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Solution Overview
Problem
In high efficiency video coding (HEVC), the determination of motion vector predictors for bi-prediction mode involves increased computational complexity and overhead due to the need for two separate searches and index transmission for each motion vector, which hampers efficient parallel processing and coding performance.
Innovation Solution
A method where a first motion vector predictor is determined for a unit of video content, and a second motion vector predictor is calculated based on the first motion vector or its predictor, reducing the need for additional candidate set searches and index transmission by using temporal distance or picture order count scaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two separate MVP candidate sets are formed and searched for bi-prediction mode, then motion vector prediction accuracy is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent merges the two separate MVP candidate set searches into a single unified search process. Instead of independently searching for MVP0 from candidate list 0 and MVP1 from candidate list 1, the method performs one joint search that considers both reference lists simultaneously, reducing computational complexity while maintaining prediction accuracy.
Solution Approach 2:
The patent performs preliminary determination of MVP0 from the first candidate set before finalizing MVP1. By establishing MVP0 first and using it as a reference point, the subsequent determination of MVP1 becomes more efficient, as the search space can be optimized based on the already-determined MVP0, thereby reducing overall computational burden.
2Measurement precision
If two MVP indices are transmitted in the bitstream for bi-prediction mode, then motion vector prediction accuracy is improved, but bitstream overhead increases
Solution Approach 1:
The patent merges the transmission of two separate MVP indices into a single unified index transmission mechanism. The single index points to a position in the combined candidate list that encodes both MVP0 and MVP1 information, thereby reducing bitstream overhead while preserving the ability to accurately predict both motion vectors for bi-prediction mode.
3Measurement precision
If two separate searches are performed for MVP candidates, then motion vector prediction accuracy is improved, but parallel processing capability is reduced
Solution Approach 1:
The patent merges the two sequential search operations into a single parallelizable search process. The unified candidate list and single index determination allow multiple threads or processing units to work simultaneously on different aspects of the search (e.g., evaluating different candidate positions, computing cost functions for multiple candidates), thereby enabling parallel processing while maintaining prediction accuracy.
Data Source
AI summary
In one embodiment, a method receives a unit of video content. The unit of video content is coded in a bi-prediction mode. A motion vector predictor candidate set is determined for a first motion vector for the unit. The method then determines a first motion vector predictor from the motion vector prediction candidate set for the first motion vector and calculates a second motion vector predictor for a second motion vector for the unit of video content. The second motion vector predictor is calculated based on the first motion vector or the first motion vector predictor.