Intra Block Copy Mode for Screen Content Video Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video coding technologies face challenges in efficiently coding screen content videos due to their unique properties, which differ from natural content videos.
Innovation Solution
The proposed system enables weighted prediction to be dynamically enabled or disabled during the coding of video blocks, using intra block copy (IBC) mode and picture order counts to determine prediction modes, and employs fractional block vectors and interpolation filtering for chroma reference samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If weighted prediction is applied to video blocks, then prediction accuracy is improved, but coding complexity increases due to additional parameters and processing requirements
Solution Approach 1:
The patent dynamically enables or disables weighted prediction based on the coding mode of each video block. When IBC mode is detected (through picture order count comparison), weighted prediction is disabled to simplify processing. When inter prediction mode is used, weighted prediction is enabled to improve accuracy. This dynamic adaptation resolves the contradiction by applying complexity only where beneficial.
Solution Approach 2:
The patent changes the prediction parameters (enabling/disabling weighted prediction) based on the coding mode determined by picture order count comparison. This parameter adaptation allows the system to switch between simple IBC mode and complex weighted prediction mode depending on the specific block requirements, optimizing the balance between accuracy and complexity.
2Productivity
If IBC mode is used for video blocks, then coding efficiency is improved through intra prediction, but prediction accuracy may deteriorate when picture order counts differ
Solution Approach 1:
The patent uses picture order count comparison as a feedback mechanism to determine the appropriate prediction mode. By comparing the picture order count of the current picture with that of the reference picture, the system feedbacks whether IBC mode is appropriate or if weighted prediction should be applied instead, ensuring accurate prediction while maintaining coding efficiency.
3Measurement precision
If fractional block vectors are used for chroma reference samples, then chroma prediction accuracy is improved, but processing complexity increases due to interpolation filtering requirements
Solution Approach 1:
The patent dynamically applies interpolation filtering only when fractional block vectors are needed for chroma reference samples. This dynamic application of the interpolation filter resolves the contradiction by providing high accuracy only when required, while avoiding unnecessary processing complexity in cases where integer vectors suffice.
Data Source
AI summary
A video block of a current picture may be coded in an intra block copy (IBC) mode. Weighted prediction may be disabled for the IBC-coded screen content video block. Fractional block vectors may be used for the chroma components of the IBC-coded video block. An interpolation filter may be utilized to generate chroma prediction samples for the video block. A decoded version of the current reference picture may be added to both reference picture list L0 and reference picture list L1 that are associated with the IBC-coded video block. When constrained intra prediction is applied, reference samples that may be used to predict an intra-coded video block may be limited to those in intra-coded neighboring blocks. The range of IBC searches may be restricted by imposing a maximum absolute value for block vectors.