Flexible Chroma Quantization Matrix Sizing in Video Decoding
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Solution Overview
Problem
Current video encoding and decoding methods in VVC have limited flexibility in quantization matrix (QM) encoding and decoding, leading to high computational complexity on the decoder side due to fixed QM sizes and bit overheads.
Innovation Solution
Determine the chroma format of a video frame and adjust the size of the quantization matrix based on the chroma format and luma transform block size, allowing flexible encoding and decoding of chroma QMs and reducing unnecessary decoding operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed QM sizes are used in VVC encoding and decoding, then the encoding and decoding process is simplified, but the flexibility of QM encoding and decoding is limited and computational complexity on the decoder side increases
Solution Approach 1:
The patent applies dynamics by making the QM size variable rather than fixed. The QM size is dynamically determined based on the chroma format and luma transform block size, allowing the system to adapt to different video content characteristics and reduce unnecessary decoding operations while maintaining flexibility across various encoding scenarios
Solution Approach 2:
The patent changes the parameter of QM size from a fixed value to a variable that depends on chroma format and luma TB size. By introducing conditional logic that adjusts QM size based on these parameters, the system achieves both flexibility and reduced computational complexity by only decoding QMs when their size is greater than zero
2Reliability
If QM encoding and decoding is performed for all chroma formats, then complete color information is preserved, but bit overheads increase due to unnecessary encoding of QMs with size zero
Solution Approach 1:
The patent extracts only the necessary QM encoding operations by checking whether the determined QM size is greater than zero before proceeding with decoding. This selective approach removes unnecessary encoding operations for chroma formats where QM size is zero, thereby reducing bit overheads while preserving complete color information where needed
Data Source
AI summary
A video encoding method and apparatus is provided. The method includes determining a chroma format of a video frame, determining, for a currently decoded first quantization matrix (QM), a size of the first QM according to the determined chroma format and a size of a luma transform block (TB) when the first QM is a chroma QM, and decoding the first QM when the size of the first QM is greater than zero. Thus, a size of a chroma QM is flexibly determined according to a chroma format and a size of a luma TB, rather than a fixed size predefined according to an identifier of the QM, thereby improving flexibility during encoding and decoding of the chroma QM. Apparatus and non-transitory computer-readable storage medium counterpart embodiments are also provided.