Palette Mode Video Coding Reducing Line Index Dynamic Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing palette mode coding techniques suffer from redundancies in copy-previous mode due to prohibited copying from certain lines, leading to reduced dynamic range and inefficient coding efficiency, especially when dealing with screen content which has different characteristics than natural content.
Innovation Solution
The method involves coding a current pixel in copy-previous mode by identifying candidate values for the previous line index and reducing them based on the number of escape pixels, and coding a current pixel in copy-above mode by using a run length value when a neighboring pixel is available, thereby improving coding efficiency by removing redundancies and adapting to screen content characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If copy-previous mode is used with full candidate values for previous line index, then coding flexibility is maintained, but coding efficiency deteriorates due to redundancies and larger dynamic range
Solution Approach 1:
The patent changes the parameter of candidate values for previous line index by reducing the dynamic range based on escape pixel positions. Instead of using the full range of possible line indices, the encoder reduces the candidate values by identifying escape pixels and adjusting the range accordingly, thereby improving coding efficiency while maintaining necessary flexibility
Solution Approach 2:
The patent introduces dynamic adjustment of the candidate value range for previous line index based on the actual content of the video data. The range is dynamically reduced by identifying escape pixels and adjusting the candidate values accordingly, allowing the system to adapt to different content characteristics and improve compression efficiency
2Productivity
If traditional coding tools are used for natural content, then natural content compression is optimized, but screen content compression efficiency deteriorates due to different characteristics
Solution Approach 1:
The patent applies local quality by introducing content-specific coding strategies. For screen content, the patent uses palette mode with copy-previous and copy-above modes that are particularly effective for sharp edges and graphic content. The coding approach is locally adapted to the content type, using different strategies for different regions and content characteristics
Solution Approach 2:
The patent changes coding parameters based on content type detection. When screen content is detected, the system activates palette mode with reduced dynamic range for previous line index. The parameters are dynamically adjusted based on content characteristics, allowing optimal compression for different content types
3Productivity
If copy-above mode is used without considering neighboring pixel availability, then coding simplicity is maintained, but coding efficiency deteriorates due to redundant information
Solution Approach 1:
The patent applies preliminary action by checking the availability of neighboring pixels before attempting to use copy-above mode. The encoder first determines whether the current pixel is in the first line of the current block and whether neighboring pixels are available, and only then decides whether to use copy-above mode with run length encoding. This preliminary check prevents redundant encoding operations
Solution Approach 2:
The patent introduces dynamic decision-making in the copy-above mode. The system dynamically determines whether to use copy-above mode based on the availability of neighboring pixels and the position of the current pixel. The coding process adapts to the local context, using copy-above mode only when beneficial and avoiding it when neighboring pixels are unavailable
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Methods incorporating extensions to copy-above mode for palette mode coding are disclosed. In one aspect, the method includes coding a current pixel of a current block of video data in copy-previous mode via coding a previous line index. The coding of the current pixel in copy-previous mode further including identifying a number of candidate values for the previous line index, identifying a number of escape pixels in a column of pixels above the current pixel in the current block, and reducing a number of candidate values of the previous line index by the number of identified escape pixels.