Video Coding Tool Control via Hierarchical Bitstream Flags
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Solution Overview
Problem
Current video compression techniques, such as H.264/AVC and HEVC, face inefficiencies as video size, resolution, and frame rate increase, necessitating improved encoding and decoding methods to enhance compression performance and image quality.
Innovation Solution
The proposed solution involves controlling the enablement of various coding tools through a syntax element at a high level in the bitstream, specifically using a piecewise linear model for luma component mapping and inverse mapping to optimize encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing compression techniques (H.264/AVC, HEVC) are used, then video data can be compressed and stored, but compression efficiency and image quality deteriorate as video size, resolution, and frame rate increase
Solution Approach 1:
The patent segments the bitstream into different hierarchical levels (high level and low level) and applies different coding tool control strategies at each level. The high level contains enable flags that control groups of coding tools, while the low level contains application flags for individual tools, allowing selective and efficient compression control.
Solution Approach 2:
The patent dynamically controls the application of coding tools based on content characteristics. The encoder determines whether to apply specific coding tools (like GMCS) based on the video content type, and this control information is adaptively signaled in the bitstream, allowing the system to optimize compression efficiency for different content scenarios.
2Productivity
If more coding tools are applied to improve compression performance, then encoding efficiency improves, but device complexity and processing overhead increase
Solution Approach 1:
The patent divides coding tool control into two segments: high-level enable flags that control groups of tools, and low-level application flags for individual tools. This segmentation allows the system to manage complexity by organizing control mechanisms hierarchically rather than handling each tool independently.
Solution Approach 2:
The high-level enable flags serve as universal control mechanisms that can enable or disable groups of coding tools simultaneously. This multi-functionality reduces the need for numerous individual control flags, thereby simplifying the overall control structure while maintaining flexibility.
3Ease of operation
If coding tools are controlled at low level with individual flags, then precise control is achieved, but bitstream size and processing overhead increase
Solution Approach 1:
The patent merges the control of multiple coding tools into high-level enable flags that govern groups of tools. By combining control functions, the system reduces the total number of flags needed in the bitstream, thereby reducing overhead while maintaining the ability to precisely control tool application through the hierarchical structure.
Solution Approach 2:
The high-level enable flags are set preliminarily to control the overall availability of coding tool groups. This preliminary control mechanism allows the system to avoid signaling individual low-level flags for tools that are not enabled at the high level, thereby reducing bitstream overhead before detailed tool-specific control is needed.
Data Source
AI summary
A method and device for controlling coding tools are provided. The video decoding method includes decoding, from a high level of a bitstream, an enable flag indicating whether one or more coding tools are enabled. The coding tools includes a first coding tool that encodes sample values using luma component mapping based on a piecewise linear model. The method includes acquiring a value of an application flag depending on a value of the enable flag, by setting the application flag indicating whether to apply the coding tools to a predetermined value, or by decoding the application flag from a low level of the bitstream, the application flag including a first application flag indicating whether to apply the first coding tool. The coding tools are operated when the value of the application flag is a value indicating that the coding tools are applied.