Palette Predictor Initializer for HEVC Self-Contained Coding Structures
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Solution Overview
Problem
The Palette coding mode in HEVC SCC faces inefficiencies due to high signaling costs and broken prediction schemes across coding structures like slices and tiles, leading to reduced coding efficiency and increased data redundancy.
Innovation Solution
Defining a palette predictor initializer at a hierarchical level above the coding structures, such as the image or sequence level, allows for shared use across independent coding structures, reducing redundant data transmission and improving encoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a palette predictor initializer is defined at the slice or tile level, then each independent coding structure can initialize its palette predictor, but the signaling cost increases due to redundant data transmission for each slice or tile
Solution Approach 1:
The palette predictor initializer is defined at a higher hierarchical level (image or sequence level) that can be shared by multiple independent coding structures (slices or tiles). This allows the same initializer to serve multiple purposes across different coding structures, reducing redundant data transmission while ensuring proper palette prediction initialization for each slice or tile.
Solution Approach 2:
Instead of providing separate palette predictor initializers for each slice or tile, the invention merges the initialization data into a single definition at a higher hierarchical level. This consolidation eliminates redundancy while maintaining the functional requirement for each independent coding structure to have its palette predictor properly initialized.
2Productivity
If palette prediction is used across coding structures, then coding efficiency improves, but the prediction scheme breaks down at slice or tile boundaries due to independent encoding requirements
Solution Approach 1:
The invention introduces a new hierarchical dimension above the slice/tile level where the palette predictor initializer is defined. This allows prediction information to flow from the higher level down to multiple independent coding structures, maintaining prediction continuity across boundaries without violating the independent encoding requirement at the slice/tile level.
Data Source
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AI summary
The invention concerns a method and a device for processing images, e.g. for encoding or decoding the images into or from a bitstream, using a palette prediction mode as defined in HEVC SCC. The images are split into hierarchical coding structures. At the decoder, the method comprises: decoding encoded data of two self-contained coding structures having the same hierarchical level, using a palette coding mode which uses, for each processed block of the two coding structures, an associated palette that comprises entries associating respective entry indexes with corresponding pixel values, wherein the palette associated with each processed pixel block is predicted from a palette predictor using prediction information from the bitstream;obtaining, from the bitstream, a palette predictor initializer associated with a coding structure hierarchically above the two self-contained coding structures; and initializing the palette predictor for each self-contained coding structure using the same obtained palette predictor initializer.