Hierarchical LMCS Flags for Loop Filter Control in Video Coding
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Solution Overview
Problem
Existing video coding standards face challenges in optimizing the use of loop filters and other processing techniques at different levels of video encoding, leading to inefficiencies in compression and decompression processes.
Innovation Solution
Implementing control flags for luma mapping with chroma scaling, adaptive loop filter, and sample adaptive offset at sequence, picture, and slice levels to dynamically enable or disable these techniques based on specific conditions, allowing for more precise control over the encoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If loop filters and processing techniques are applied at all levels (sequence, picture, slice) to improve coding efficiency, then compression performance is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent segments the video encoding structure into multiple hierarchical levels (sequence level, picture level, slice level) and introduces control flags at each level to independently enable or disable loop filters and processing techniques. This segmentation allows selective application of processing techniques to specific regions or portions of video data, improving coding efficiency where needed while avoiding unnecessary processing elsewhere, thus resolving the contradiction between compression performance and encoding complexity.
Solution Approach 2:
The patent implements dynamic control mechanisms where control flags can be set at different hierarchical levels to dynamically enable or disable processing techniques based on local video characteristics and requirements. This dynamic approach allows the encoding system to adaptively apply loop filters and other processing techniques only where beneficial, rather than uniformly across all video data, thereby improving coding efficiency without proportionally increasing overall encoding complexity.
2Adaptability or versatility
If multiple control flags are signaled at different levels to enable precise control of processing techniques, then adaptability is improved, but loss of information and processing overhead increase
Solution Approach 1:
The patent applies the local quality principle by allowing different control flag settings at different hierarchical levels (sequence, picture, slice) to enable or disable processing techniques locally rather than globally. This means that processing techniques can be selectively applied to specific pictures, slices, or regions based on their local characteristics, providing fine-grained control flexibility while avoiding the transmission of redundant control information across the entire video stream, thus balancing adaptability with bitstream efficiency.
3Manufacturing precision
If loop filters are applied more extensively to improve decompression quality, then manufacturing precision of video output is improved, but use of energy and processing time increase
Solution Approach 1:
The patent implements partial action by allowing control flags to selectively enable loop filters and processing techniques only for specific pictures, slices, or regions where they are most beneficial, rather than applying them uniformly to all video data. This partial application of processing techniques improves decompression quality in critical areas while avoiding unnecessary processing energy consumption in areas where loop filters provide minimal benefit, thus resolving the contradiction between output quality and processing energy.
Data Source
AI summary
Methods and apparatuses for video encoding, comprising: receiving a video sequence; encoding the video sequence by using control flags for luma mapping with chroma scaling (LMCS) at a sequence level, a picture level, or a slice level, wherein the sequence level, the picture level, and the slice level are levels ranking from high to low; signaling a first control flag indicating whether the LMCS is enabled at a first level; and in response to the first control flag indicating the LMCS is enabled at the first level, signaling a second control flag indicating whether LMCS is enabled at a second level, wherein: the LMCS is enabled at the second level when a value of the second control flag equals to 1; the LMCS is disabled at the second level when the value of the second control flag equals to 0; and the second level is a lower level than the first level.