Video Chroma Quantization for Misaligned Blocks Using Predictive QP
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video coding standards, such as ITU-T H.265 and JEM, face challenges in efficiently determining quantization parameters for chroma coding blocks that are misaligned with luma coding blocks, leading to suboptimal video compression and decoding efficiency.
Innovation Solution
The method involves determining quantization parameters for chroma coding blocks independently of luma components by using a predictive quantization parameter derived from luma quantization parameters and adding a delta quantization parameter, allowing for the generation of level values based on these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If quantization parameters are determined using existing video coding standards (ITU-T H.265, JEM) for misaligned chroma blocks, then video compression is performed, but coding efficiency and decoding performance are suboptimal
Solution Approach 1:
The patent changes the quantization parameter determination method by introducing a predictive QP derived from luma QP and a delta QP specific to chroma blocks. This parameter transformation allows independent optimization of chroma quantization without being constrained by existing standard limitations, thereby improving coding efficiency while maintaining parameter accuracy.
Solution Approach 2:
The patent segments the quantization parameter determination into two independent parts: a predictive QP component derived from luma QP and a delta QP component specific to chroma blocks. This segmentation allows each component to be optimized independently, resolving the contradiction between overall coding efficiency and specific quantization accuracy for misaligned chroma blocks.
2Adaptability or versatility
If chroma and luma coding blocks are aligned in existing standards, then processing is simplified, but misaligned chroma blocks cannot be optimized independently
Solution Approach 1:
The patent introduces an intermediary predictive QP that bridges luma and chroma quantization parameters. This intermediary allows independent optimization of chroma blocks while maintaining a systematic relationship with luma, avoiding the need for direct alignment and reducing the complexity of independent chroma processing.
Solution Approach 2:
The patent performs preliminary determination of the predictive QP from luma parameters before adding the chroma-specific delta QP. This preliminary action simplifies the overall process by pre-computing the baseline quantization parameter, allowing the complex chroma-specific adjustments to be made as a separate, optimized step.
3Manufacturing precision
If a single quantization parameter is used for both luma and chroma, then processing is simplified, but optimization for specific chroma blocks is lost
Solution Approach 1:
The patent applies local quality by introducing a chroma-specific delta QP that can vary for different chroma blocks, while the predictive QP provides a shared baseline. This allows precise optimization for each chroma block's local characteristics without requiring completely independent quantization parameters for every block, thus balancing precision with parameter quantity.
Data Source
AI summary
A method of encoding video data by a device is provided. Transform coefficient values associated with a chroma coding block are received. The chroma coding block is one of chroma coding blocks resulting from partitioning a chroma coding tree block and misaligned with a luma coding tree block corresponding to the chroma coding tree block and partitioned into luma coding blocks which are organized into quantization groups such that luma quantization parameters are determined for the luma coding tree block. One of the luma quantization parameters that is mapped to the chroma coding block is identified. A predictive quantization parameter is derived by using a value derived from the identified luma quantization parameter. A chroma quantization parameter is determined by adding a delta quantization parameter associated with each of the chroma coding blocks to the predictive quantization parameter. Level values are generated based on the determined chroma quantization parameter.