Adaptive Multiple Transform Coding Using Truncated Unary Codewords
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding techniques face inefficiencies in signaling overhead, which affects coding gains and adaptability in advanced video codecs like HEVC and next-generation standards.
Innovation Solution
The implementation of adaptive multiple transform (AMT) designs with reduced signaling overhead, utilizing truncated unary codewords to determine and apply multiple transform schemes for video blocks, enhancing coding efficiency and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adaptive multiple transform designs are used to improve coding flexibility and coding gains, then coding adaptability and compression efficiency are improved, but signaling overhead increases
Solution Approach 1:
The transform selection process is segmented into multiple stages: first determining a primary transform type (e.g., DCT, DST), then conditionally determining a secondary transform type. This segmentation allows the signaling to be divided into mandatory parts (primary transform) and optional parts (secondary transform), reducing overall overhead while maintaining adaptability.
Solution Approach 2:
The transform coding system dynamically adapts the signaling requirements based on the determined transform types. When a secondary transform is selected, additional signaling bits are transmitted; when not selected, fewer bits are transmitted. This dynamic signaling approach optimizes the balance between coding adaptability and signaling overhead.
2Productivity
If multiple transform schemes are applied to enhance coding flexibility and compression efficiency, then coding gains are improved, but device complexity increases
Solution Approach 1:
The system implements a universal transform selection mechanism that can handle multiple transform types (DCT, DST, and their combinations) through a unified decision-making process. The encoder and decoder both follow the same logic flow for determining primary and secondary transforms, simplifying the overall system architecture despite supporting multiple coding modes.
Solution Approach 2:
The system changes operational parameters (transform types, signaling bit counts, processing steps) based on the analyzed video block characteristics. By adjusting these parameters dynamically rather than implementing all possible transforms simultaneously, the system achieves high coding gains while managing device complexity.
3Loss of information
If truncated unary codewords are used to reduce signaling overhead, then signaling efficiency is improved, but decoding complexity increases
Solution Approach 1:
The truncated unary codeword encoding method is applied symmetrically to both encoder and decoder operations. The same codeword table and decoding logic are used at both ends, ensuring that the complexity increase at the decoder is offset by the significant reduction in signaling overhead, while maintaining implementation simplicity.
Data Source
AI summary
An example device for decoding video data includes a memory configured to store video data; and a processor implemented in circuitry and configured to decode a truncated unary codeword representing a multiple transform (MT) scheme for a current block of the video data to determine the MT scheme; apply the MT scheme to transform coefficients of the current block to produce residual data for the current block of video data; and decode the current block using the residual data. The MT scheme may include a plurality of transforms, such as a horizontal transform and a vertical transform, a primary transform and a second transform, or any combination of separable and/or non-separable transforms. Thus, a single truncated unary codeword may represent the entire MT scheme, that is, each of a plurality of transforms of the MT scheme.