Rice Parameter Derivation for Wavefront Parallel Video Decoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video coding technologies face inefficiencies due to conflicts between history-based Rice parameter derivation and parallel processing, leading to unstable or inefficient video coding, particularly in video coding standards like VVC, which can hinder the use of parallel processing and increase computational complexity.
Innovation Solution
Implement history-based Rice parameter derivation by limiting the dependency between coding tree units (CTUs) within the same CTU row and aligning it with parallel processing dependencies, using techniques such as re-initializing history counters for each CTU row and implementing storage-synchronization processes to avoid conflicts, thereby enabling efficient parallel processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If history-based Rice parameter derivation is used to improve coding efficiency, then coding gain is improved, but parallel processing capability deteriorates due to dependencies between CTUs
Solution Approach 1:
The patent divides the video data into multiple CTU rows and processes each row independently with its own history counter. This segmentation allows parallel processing of different CTU rows while maintaining history-based Rice parameter derivation within each row, thus resolving the contradiction between coding efficiency and parallel processing capability.
Solution Approach 2:
The patent applies history-based Rice parameter derivation locally within each CTU row rather than globally across the entire video data. By initializing history counters separately for each CTU row, the patent maintains the coding gain benefits locally while enabling parallel processing across different rows, thus resolving the technical contradiction.
2Speed
If parallel processing is implemented to reduce processing time, then processing speed is improved, but coding stability deteriorates due to conflicts in history counter management
Solution Approach 1:
The patent segments the history counter state into multiple independent counters, one for each CTU row. This allows parallel processing of different CTU rows without conflicts in history counter management, maintaining coding stability while improving processing speed through parallelization.
Solution Approach 2:
The patent initializes history counters for each CTU row before parallel processing begins. This preliminary action ensures that each parallel processing thread starts with a clean, independent state, preventing conflicts and maintaining coding stability during parallel execution.
3Productivity
If history counter is maintained across all CTUs to maintain coding gain, then coding efficiency is improved, but computational complexity increases due to dependency management
Solution Approach 1:
The patent segments the history counter into multiple independent counters for different CTU rows. This reduces the complexity of dependency management compared to a single global history counter, while still maintaining coding gain within each row. The segmentation simplifies the state management required for parallel processing.
Data Source
AI summary
In some embodiments, a video decoder decodes a video from a bitstream of the video using a history-based Rice parameter derivation along with the wavefront parallel processing (WPP). The video decoder accesses a binary string representing a partition of the video and processes each coding tree unit (CTU) in the partition to generate decoded coefficient values in the CTU. The process includes prior to decoding the CTU, determining whether WPP is enabled and the CTU is the first CTU of a current CTU row in the partition, and if so, setting a history counter to an initial value. The process further includes decoding the CTU by calculating the Rice parameters for transform units (TUs) in the CTU based on the value of the history counter and decoding the binary string corresponding to the TUs in the CTU into coefficient values of the TUs based on the calculated Rice parameters.