Chroma Quantization Adjustment for Balanced Video Coding Gain
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Solution Overview
Problem
Existing video encoding and decoding technologies face challenges in achieving optimal compression efficiency, particularly in balancing the coding gain between luma and chroma components, leading to inefficiencies in bit-rate allocation and visual quality.
Innovation Solution
Adopting a method to adjust chroma quantization parameters based on encoding performance levels, using different sets of chroma quantization parameters for motion-predicted and non-motion-predicted images, and signaling these parameters in the bitstream to achieve balanced coding efficiency between luma and chroma components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chroma quantization parameters are adjusted based on encoding performance levels, then coding efficiency is improved and bit-rate is reduced, but device complexity increases due to multiple parameter sets and selection logic
Solution Approach 1:
The patent adjusts chroma quantization parameters (QPCb, QPCr) based on encoding performance levels and motion prediction status. Different parameter sets are selected depending on whether the image is motion-predicted or not, allowing optimization of coding efficiency while managing complexity through conditional parameter selection rather than universal complexity increases
Solution Approach 2:
The patent applies different chroma quantization parameter sets to different regions or conditions: one set for motion-predicted images and another for non-motion-predicted images. This localized approach optimizes compression for each specific case without requiring the system to handle all possible scenarios with maximum complexity
2Productivity
If different sets of chroma quantization parameters are used for motion-predicted and non-motion-predicted images, then coding gain is optimized, but ease of operation deteriorates due to parameter selection complexity
Solution Approach 1:
The patent dynamically selects chroma quantization parameters based on the motion prediction status of the image. The system adapts its operation mode (different parameter sets) according to the input characteristics, automatically adjusting to optimize coding gain without requiring manual intervention or complex user decisions about which parameters to use
3Productivity
If bit-rate is reallocated to prioritize luma components, then overall bit-rate is reduced while maintaining visual quality, but chroma component quality may deteriorate
Solution Approach 1:
The patent applies different quantization strategies to different color components (luma and chroma) and different image types (motion-predicted vs. non-motion-predicted). By locally optimizing parameters for each component and condition, the system reduces overall bit-rate while maintaining acceptable chroma quality through selective parameter adjustment rather than uniform compression
Solution Approach 2:
The patent changes chroma quantization parameters based on encoding performance levels and motion prediction status. This dynamic parameter adjustment allows the system to allocate bits more efficiently across different components and conditions, reducing total bit-rate while maintaining visual quality through intelligent parameter selection
Data Source
AI summary
A video coding system uses a value of a chroma quantization parameter table to quantize or de-quantize chroma values of a block of the video, the chroma quantization parameter table being directly coded in a set of parameters at the picture level or at the sequence level of the coded video stream. A corresponding encoding method, encoding device, decoding method, decoding device, and non-transitory readable medium are proposed.