SAO Merge Mode Quantization Correction for Video Encoding
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Solution Overview
Problem
In video encoding, the application of SAO merge mode is limited when adjacent CTUs have different quantization values, leading to inadequate suppression of mosquito distortion and increased encoding information volume.
Innovation Solution
A video encoding apparatus that corrects SAO parameters based on quantization values for both the CTU to be encoded and its adjacent reference CTU, allowing the SAO merge mode to be applied even when quantization values differ, thereby improving encoding efficiency and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the SAO merge mode is applied to CTUs with different quantization values, then the encoding information volume is reduced and encoding efficiency is improved, but the mosquito distortion suppression becomes inadequate and image quality deteriorates
Solution Approach 1:
The patent corrects SAO filter parameters (offset values and classification types) based on the quantization value differences between reference CTUs and current CTUs. By adjusting these parameters according to quantization value ratios, the system maintains effective mosquito distortion suppression even when applying merge mode across CTUs with different quantization values, thus resolving the contradiction between encoding efficiency and image quality.
2Object-affected harmful factors
If the SAO parameters are individually set for each CTU, then the mosquito distortion is suppressed effectively, but the encoding information volume increases
Solution Approach 1:
The patent employs the SAO merge mode where current CTUs inherit SAO parameters from adjacent reference CTUs instead of encoding them independently. This merging approach significantly reduces the encoding information volume for SAO parameters while maintaining effective mosquito distortion suppression through the parameter correction mechanism that adapts inherited parameters to local quantization characteristics.
3Productivity
If the quantization value is adjusted for fixed bit rate control, then the bit rate is controlled effectively, but the appropriate SAO parameters vary across CTUs requiring more encoding information
Solution Approach 1:
The patent dynamically adjusts SAO filter parameters based on quantization value differences between reference and current CTUs. When quantization values vary across CTUs for bit rate control, the system corrects inherited SAO parameters by applying quantization value ratios, ensuring appropriate filtering for each CTU's local characteristics without requiring full independent parameter encoding, thus maintaining both bit rate control and parameter efficiency.
Data Source
AI summary
A video encoding apparatus corrects filter coefficients of an in-loop filter applied to an encoded reference block adjacent to a block to be encoded, based on a quantization value applied to the reference block and a quantization value applied to the block to be encoded when a mode of an in-loop filter applied to the block to be encoded is same as a mode of the in-loop filter applied to the reference block, uses the corrected filter coefficients to apply the in-loop filter to a locally-decoded block that is obtained by encoding the block to be encoded once and decoding the encoded block to be encoded, and adds, to encoded data of the block to be encoded, information indicating that the block to be encoded refers to the reference block for the in-loop filter.