Video Coding SAO Parameter Determination via Quantization Metrics
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Solution Overview
Problem
Current High Efficiency Video Coding (HEVC) standards face complexity and resource demands in determining Sample Adaptive Offset (SAO) parameters, particularly due to the need for transmitting these parameters in the bitstream and the complexity of rate distortion criteria, which is challenging for real-time applications.
Innovation Solution
The method involves determining SAO parameters independently of the sample values of the reconstructed frame area, reducing computational complexity and the need to transmit all SAO parameters, by using prefixed or derived offsets based on quantization parameters, transform unit sizes, and bit depth, and selecting filtering types like Edge Offset filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional SAO parameter determination methods are used, then video quality is improved, but computational complexity and resource demands increase significantly
Solution Approach 1:
The patent changes the parameters used for SAO determination from complex rate distortion criteria to simpler metrics based on quantization parameters, transform unit sizes, and bit depth. This allows the decoder to determine SAO parameters with reduced computational complexity while maintaining effective video quality improvement
Solution Approach 2:
The patent extracts and transmits only essential SAO parameters (such as offset values and filtering type indicators) in the bitstream, while the decoder independently determines the remaining parameters using simplified criteria. This separation reduces the burden of transmitting all parameters and lowers overall computational complexity
2Measurement precision
If all SAO parameters are transmitted in the bitstream, then decoding accuracy is improved, but bitstream size increases
Solution Approach 1:
The patent extracts only the most essential SAO parameters (offset values and filtering type) for transmission in the bitstream, while the decoder independently determines other parameters using simplified criteria based on quantization parameters, transform unit sizes, and bit depth, thereby reducing bitstream size while maintaining decoding accuracy
Solution Approach 2:
The patent uses copying of SAO parameters from co-located blocks or previously decoded blocks when applicable, allowing the decoder to reuse parameters without transmitting them again, thus reducing bitstream size while maintaining consistent decoding quality across similar regions
3Manufacturing precision
If complex rate distortion criteria are used for SAO parameter determination, then coding optimality is improved, but real-time processing capability deteriorates
Solution Approach 1:
The patent changes the determination criteria from complex rate distortion optimization to simpler rules based on quantization parameters, transform unit sizes, and bit depth, enabling real-time processing while maintaining effective coding optimality through the decoder's independent parameter determination
Solution Approach 2:
The patent performs preliminary determination of SAO parameters at the decoder side using pre-defined simplified criteria, eliminating the need for complex real-time rate distortion calculations at the encoder, thus enabling real-time processing capability while maintaining coding optimality
Data Source
AI summary
The invention relates to video coding. A method of encoding or decoding such a video sequence according to the invention comprises: obtaining a reconstructed frame area made of an array of sample values; applying a sample adaptive offset, SAO, filtering to the reconstructed frame area based on SAO parameters; wherein at least one of the SAO parameters is determined independently of the sample values of the reconstructed frame area. Preferably, the sample-independent SAO parameters define an Edge Offset filtering.