Bi-Directional Motion Vector Prediction for Low-Complexity Video Decoding
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Solution Overview
Problem
Existing video encoding and decoding methods for bi-directional prediction are complex and inefficient for real-time transmission of high-resolution videos, requiring multiple motion estimations and increased memory bandwidth, which is not suitable for low-latency systems.
Innovation Solution
A method and apparatus that derive a second motion vector using a first motion vector and a candidate list, determining the second motion vector based on the distance between candidate prediction motion vectors and the first motion vector, reducing the need for additional motion estimation and memory fetches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If bi-directional prediction is used to improve compression efficiency, then compression efficiency is improved, but device complexity and processing time increase due to requiring multiple motion estimations
Solution Approach 1:
The patent extracts and transmits only the first motion vector information in the bitstream, while deriving the second motion vector through calculation using the first motion vector and candidate prediction motion vectors. This extraction approach avoids transmitting redundant information and reduces the complexity of bi-directional prediction while maintaining compression efficiency.
Solution Approach 2:
The second motion vector is derived automatically through calculation using the relationship between the first motion vector and candidate prediction motion vectors, rather than requiring separate transmission or independent motion estimation. This self-service mechanism reduces processing complexity and memory bandwidth requirements.
2Reliability
If traditional bi-directional prediction is used, then prediction accuracy is maintained, but loss of time increases due to requiring multiple motion estimations and memory fetches
Solution Approach 1:
The patent performs preliminary calculation to derive the second motion vector using the first motion vector and candidate prediction motion vectors before actual decoding. This preliminary action reduces the need for additional motion estimation and memory fetches during real-time processing, thereby reducing processing time while maintaining prediction accuracy.
Solution Approach 2:
The first motion vector serves as an intermediary that enables the derivation of the second motion vector through calculation, rather than requiring independent motion estimation. This intermediary approach maintains prediction accuracy while significantly reducing processing time and computational complexity.
3Reliability
If multiple motion vectors are transmitted to improve prediction accuracy, then prediction accuracy is improved, but loss of information transmission increases due to additional bitstream data
Solution Approach 1:
The patent extracts and transmits only the essential first motion vector information in the bitstream, while the second motion vector is derived through calculation. This extraction approach maintains prediction accuracy by preserving the key motion information while minimizing redundant data transmission.
Solution Approach 2:
The patent changes the parameter representation by transmitting motion vector difference values or indices rather than complete motion vector information. This parameter transformation reduces the amount of information that needs to be transmitted while maintaining the ability to reconstruct accurate motion vectors for prediction.
Data Source
AI summary
Provided are a video decoding method and apparatus for obtaining, from a bitstream, information about a first motion vector of a current block, determining, based on the information about the first motion vector, the first motion vector, determining a candidate list including a plurality of candidate prediction motion vectors for determining a second motion vector of the current block, determining, based on a distance between each of the plurality of candidate prediction motion vectors and the first motion vector, one of the plurality of candidate prediction motion vectors as the second motion vector, and determining a motion vector of the current block by using the first motion vector and the second motion vector.