Palette Mode Video Coding Pixel Scan Order Inference
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Solution Overview
Problem
Traditional video coding techniques are inefficient for compressing computer-generated screen content, which has discrete-tone and high contrast characteristics, as they assume continuous-tone and smooth images.
Innovation Solution
The implementation of palette-based video coding techniques, where a video coder represents video data using a palette of colors, encoding pixel indices rather than actual pixel values, allowing for efficient compression of screen content by determining and signaling appropriate scanning orders and palette sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional video coding techniques are used, then continuous-tone and smooth images can be processed, but compression efficiency for discrete-tone screen content deteriorates
Solution Approach 1:
The patent changes the fundamental parameters of video coding by introducing palette-based representation instead of direct pixel value encoding. It uses discrete palette indices to represent colors rather than continuous-tone pixel values, and applies specific scan orders (raster, diagonal, etc.) optimized for screen content characteristics. This parameter transformation enables efficient compression of discrete-tone screen content while maintaining compatibility with existing video coding frameworks.
2Productivity
If palette-based video coding is implemented, then compression efficiency for screen content improves, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining palettes of colors that will be used in screen content regions. These palettes are constructed before encoding based on analysis of the screen content characteristics, and the scan orders are predetermined based on the discrete-tone nature of the content. This preliminary preparation reduces the complexity during actual encoding by avoiding real-time complex computations.
Solution Approach 2:
The patent applies local quality by using different coding approaches for different regions of the video content. Palette-based coding is selectively applied to screen content regions where it provides benefits, while traditional coding methods can be used for other regions. The scan order and palette construction are locally optimized for each screen content region's specific characteristics.
3Measurement precision
If block-level syntax elements are transmitted for every palette mode encoded block, then decoding accuracy improves, but bitrate increases
Solution Approach 1:
The patent extracts and removes redundant block-level syntax elements from the bitstream. Instead of transmitting scan order information for every palette mode encoded block, the invention infers the scan order from the block's position and characteristics. Only essential information is transmitted, while redundant information is derived at the decoder side, significantly reducing bitrate while maintaining decoding accuracy.
Solution Approach 2:
The patent applies self-service by enabling the decoder to autonomously determine scan order information without requiring explicit transmission. The decoder uses the block's position in the picture and the inferred pixel scan order to correctly decode palette mode encoded blocks. This self-determination mechanism eliminates the need for additional syntax elements, reducing bitrate while preserving decoding accuracy.
Data Source
AI summary
In an example, a method of processing video data may include inferring a pixel scan order for a first palette mode encoded block of video data without receiving a block-level syntax element having a value representative of the pixel scan order for the first palette mode encoded block. The method may include decoding the first palette mode encoded block of video data using the inferred pixel scan order. The method may include receiving a block-level syntax element having a value representative of a pixel scan order for a second palette mode encoded block of video data. The method may include determining the pixel scan order for the second palette mode encoded block of video data based on the received block-level syntax element. The method may include decoding the second palette mode encoded block of video data using the determined pixel scan order.