BCIM Index Map Coding Using Reused HEVC Syntax Structures
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Solution Overview
Problem
The current design of base color index map (BCIM) mode in the HEVC standard and its implementation in reference software face complications due to the introduction of many new syntax elements and the use of tools not included in the standard, leading to inefficient encoding and decoding processes.
Innovation Solution
Innovations in BCIM mode include reusing syntax structures for transform coefficients, optimizing index map mapping and prediction strategies, and handling exception values to simplify implementation and improve coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If new syntax elements and structures are introduced for base color mapping and index map in BCIM mode, then the functionality and capability of BCIM mode are enhanced, but the implementation complexity and device complexity increase significantly
Solution Approach 1:
The patent applies universality by enabling the existing coefficient coding syntax structure to serve dual purposes: it can encode both transform coefficients in conventional modes and index map data in BCIM mode. This eliminates the need for separate syntax structures for BCIM mode, thereby reducing implementation complexity while maintaining enhanced functionality.
Solution Approach 2:
The patent merges the encoding of index map data with the existing transform coefficient coding framework. By combining these previously separate functions into a unified syntax structure, the patent reduces the number of separate syntax elements and structures needed, directly addressing the implementation complexity issue while preserving BCIM mode capabilities.
2Productivity
If tools not included in the HEVC standard are used for encoding and decoding base color mapping and index map, then the coding efficiency of BCIM mode can be improved, but the ease of manufacture and standard compliance become problematic
Solution Approach 1:
The patent makes the coefficient coding syntax structure universal by enabling it to handle both transform coefficients and index map data. This allows the standard-compliant tool to achieve improved coding efficiency for BCIM mode without requiring proprietary or non-standard tools, thus resolving the contradiction between coding efficiency and standard compliance.
Solution Approach 2:
The patent effectively copies the proven coefficient coding methodology and applies it to the index map data in BCIM mode. This copying of an existing, standard-compliant tool to a new application domain achieves coding efficiency improvements while maintaining full standard compliance, avoiding the need for custom non-standard tools.
3Device complexity
If the coefficient coding syntax structure is reused for index map data in BCIM mode, then the device complexity is reduced and implementation is simplified, but the measurement precision and coding accuracy may be affected
Solution Approach 1:
The patent applies local quality by allowing the coefficient coding syntax structure to be adapted locally for index map data while maintaining its original functionality for transform coefficients. The syntax structure is configured appropriately for each data type it handles, ensuring coding accuracy is preserved for index map data despite using a shared syntax framework.
Solution Approach 2:
The patent utilizes parameter changes within the coefficient coding syntax structure to accommodate index map data encoding. By adjusting parameters such as coefficient significance flags, run-length encoding parameters, and context models to suit index map characteristics, the patent maintains coding accuracy while benefiting from the simplified unified syntax structure.
Data Source
AI summary
Innovations in the use of base color index map (“BCIM”) mode during encoding and/or decoding simplify implementation by reducing the number of modifications made to support BCIM mode and/or improve coding efficiency of BCIM mode. For example, some of the innovations involve reuse of a syntax structure that is adapted for transform coefficients to instead signal data for elements of an index map in BCIM mode. Other innovations relate to mapping of index values in BCIM mode or prediction of elements of an index map in BCIM mode. Still other innovations relate to handling of exception values in BCIM mode.