Boundary Pixel Padding with Bi-Directional Motion Vectors
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Solution Overview
Problem
Existing video coding techniques face inefficiencies in handling bi-directional inter-predicted blocks that extend beyond picture boundaries, leading to inaccurate padding values and increased bitrate due to residual data.
Innovation Solution
Utilize bi-directional motion information to calculate accurate padding values for blocks adjacent to picture boundaries, forming intermediate padding blocks using multiple motion vectors to reduce residual data and bitrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional padding techniques are used for blocks at picture boundaries, then the encoding process is simple, but the padding values are inaccurate leading to increased residual data and bitrate
Solution Approach 1:
The patent performs preliminary motion compensation to generate intermediate padding blocks before final padding value assignment. By pre-calculating motion-compensated pixel values at picture boundaries using motion vectors from bi-directional inter-prediction, the system prepares accurate reference data in advance, eliminating the need for complex post-processing and improving padding accuracy without proportionally increasing overall encoding complexity
Solution Approach 2:
The patent introduces intermediate padding blocks as a mediator between motion vector calculation and final padding assignment. These intermediate blocks serve as a bridge that holds motion-compensated pixel values, allowing the system to decouple the motion estimation process from the final padding application, thereby improving accuracy while managing complexity through staged processing
2Measurement precision
If bi-directional motion vectors are used to calculate padding values, then padding accuracy improves, but computational complexity increases
Solution Approach 1:
The patent segments the padding calculation process into distinct stages: generating intermediate padding blocks using first motion vectors, generating second intermediate padding blocks using second motion vectors, and finally combining them to produce final padding values. This segmentation allows the computational workload to be distributed and optimized at each stage, reducing peak computational power requirements while maintaining high accuracy through the use of multiple motion vectors
3Loss of information
If accurate padding values are generated using bi-directional prediction, then residual data is reduced, but the encoding/decoding process becomes more complex
Solution Approach 1:
The patent implements self-service by having the decoding process reuse the same intermediate padding blocks that were generated during encoding. The decoder performs identical motion compensation operations using the transmitted motion vectors to regenerate the same intermediate blocks, ensuring consistency without requiring additional communication overhead or complex synchronization mechanisms, thereby reducing residual data while managing decoding complexity
Data Source
AI summary
A device for decoding video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: determine that a boundary block of a picture of the video data is bi-directional inter-predicted using a first motion vector and a second motion vector, the boundary block having an edge that touches an edge of the picture; decode the picture, including decoding the boundary block; form a first intermediate padding block using the first motion vector; form a second intermediate padding block using the second motion vector; form a padding block using the first intermediate padding block and the second intermediate padding block; and assign padding values of the padding block to a padding region of the picture neighboring the boundary block on an opposite side of the edge of the picture.