Coding Tree Unit Transform Skip Flag Decoding for VVC Bandwidth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding standards, such as HEVC, face challenges in efficiently encoding and decoding high-resolution and high-frame-rate video formats, particularly in real-time applications like immersive video, due to increased bandwidth demands and implementation costs, especially when processing diverse sections of frames in parallel.
Innovation Solution
The VVC standard employs a block-based codec structure with coding tree units, separate and shared coding trees for luma and chroma channels, and adaptive transform skipping mechanisms, allowing for flexible rate control and efficient decoding of coding units by determining secondary transform indices based on skip flags and transform requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If video data is encoded using high-resolution and high-frame-rate formats to improve video quality, then video quality is improved, but bandwidth requirements increase
Solution Approach 1:
The frame is divided into multiple sections that can be processed and transmitted independently. Each section can be encoded at different resolutions and frame rates according to its importance and the viewer's needs, allowing selective transmission of high-quality data where most beneficial while reducing overall bandwidth consumption.
Solution Approach 2:
Different regions of the video frame are encoded with different quality levels. Important regions (such as areas with significant motion or detail) are encoded at high resolution and frame rate, while less important regions use lower quality encoding, optimizing the balance between video quality and bandwidth usage.
2Productivity
If multiple sections of frames are processed in parallel to improve processing speed, then processing speed is improved, but implementation complexity increases
Solution Approach 1:
The video processing pipeline is divided into independent section processors that can operate in parallel. Each processor handles a specific section of the frame independently, enabling simultaneous processing of multiple sections without requiring complex inter-processor coordination, thus improving speed while managing complexity.
Solution Approach 2:
A single decoder core is designed to handle multiple sections sequentially by receiving a multiplexed bitstream containing data from all sections. This universal decoder can process any section at any time, eliminating the need for multiple dedicated decoders and reducing overall system complexity while maintaining the benefits of parallel processing through bitstream multiplexing.
3Device complexity
If a single-core decoder is used to maintain simplicity, then device complexity is reduced, but processing high-resolution video efficiently becomes difficult
Solution Approach 1:
The single-core decoder is designed as a universal processor capable of efficiently decoding any section of the frame. By receiving a multiplexed bitstream that organizes data from multiple sections in a predictable sequence, the single core can process high-resolution video efficiently through optimized sequential access patterns and buffer management, achieving performance comparable to multi-core systems without the added complexity.
Data Source
AI summary
Decoding a coding unit of a coding tree from a coding tree unit, the coding unit having a luma colour channel and at least one chroma colour channel. Decoding a luma transform skip flag for a luma transform block; decoding at least one chroma transform skip flag, each chroma transform skip flag corresponding to one of at least one chroma transform block; determining a secondary transform index by decoding a secondary transform index if at least one of the luma transform skip flag and the at least one chroma transform skip flags indicates that a transform of the transform block is not to be skipped, and determining the secondary transform index to indicate that a secondary transform is not to be applied if all of the luma transform skip flag and the at least one chroma transform skip flags indicate transforms of the respective transform blocks are to be skipped.