Neighboring Motion Prediction for Low-Bit Video Decoding
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Solution Overview
Problem
Existing image encoding and decoding methods struggle to efficiently encode and decode motion information with a small number of bits, particularly in codecs like H.264 AVC and HEVC, due to the limitations in predicting motion vectors and residual blocks.
Innovation Solution
The method involves encoding and decoding current motion information by utilizing neighboring motion information, where change information is used to alter the prediction direction of neighboring blocks, and differential motion vectors are applied to scale motion vectors, allowing selection of reference pictures from specific lists based on distance and direction, thereby optimizing bit usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion vectors are predicted using conventional methods in H.264 AVC and HEVC, then prediction accuracy can be maintained, but the number of bits required to encode motion information increases
Solution Approach 1:
The patent changes the parameter representation by encoding the difference between motion vectors instead of encoding full motion vectors. This parameter transformation reduces the bit requirement while maintaining prediction accuracy, as the difference between adjacent block motion vectors is typically smaller than the absolute values.
Solution Approach 2:
The patent performs preliminary encoding of motion vectors for adjacent blocks before encoding the current block's motion vector. This allows the decoder to reconstruct neighboring motion information first, which is then used to predict the current block's motion vector, reducing the bits needed for the current block.
2Measurement precision
If more motion information is encoded to improve prediction accuracy, then reconstruction quality improves, but compression efficiency decreases
Solution Approach 1:
The patent copies motion information from adjacent blocks to predict the current block's motion vector. Instead of encoding redundant full motion vectors, it utilizes the copied neighboring motion information, achieving good reconstruction quality with fewer bits and thus improving compression efficiency.
3Device complexity
If conventional motion vector prediction is used, then decoding complexity remains manageable, but bit usage for motion information is excessive
Solution Approach 1:
The patent implements a self-service mechanism where the decoder uses already-decoded neighboring block motion vectors to predict the current block's motion vector. This self-referential approach reduces bit usage without significantly increasing decoding complexity, as the required neighboring information is already available in the decoding buffer.
Data Source
AI summary
A method, performed by a decoding apparatus, of decoding motion information, including: obtaining change information indicating whether to change motion information of a neighboring block of a current block; based on the change information indicating to change the motion information, determining a prediction direction of the current block by changing a prediction direction of the neighboring block; based on the prediction direction of the neighboring block being a first uni-direction and the prediction direction of the current block being a second uni-direction or a bi-direction, selecting a reference picture of the second uni-direction of the current block from a second reference picture list; obtaining a motion vector of the second uni-direction of the current block; and reconstructing the current block using a reference block indicated by the motion vector of the second uni-direction of the current block.