SAO Bitstream Coding for Parallel HEVC Video Processing
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Solution Overview
Problem
The existing moving picture coding and decoding methods using Sample Adaptive Offset (SAO) in the HEVC standard face inefficiencies in processing due to insufficient parallel processing capability and redundant bit length, leading to increased coding and decoding burdens.
Innovation Solution
A moving picture coding method that employs context adaptive binary arithmetic coding for first SAO information with variable probability values and continuous bypass arithmetic coding for second and third SAO information using fixed probability values, allowing for increased parallel processing efficiency by placing coded second and third information after the first information in the bit stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If context adaptive binary arithmetic coding with variable probability values is used for all SAO information, then coding efficiency is improved, but processing efficiency deteriorates due to sequential processing requirements
Solution Approach 1:
The patent segments SAO information into two categories: first SAO information (sao_type_idx, sao_offset) coded with context adaptive binary arithmetic coding for coding efficiency, and second SAO information (sao_band_position, sao_offset_sign) coded with bypass arithmetic coding for parallel processing capability. This segmentation allows different coding methods to be applied to different data types based on their characteristics and processing requirements.
Solution Approach 2:
The patent applies different coding qualities to different parts of the SAO information structure. Context adaptive binary arithmetic coding with variable probability values is applied locally to first SAO information where coding efficiency is critical, while bypass arithmetic coding with fixed probability values is applied locally to second SAO information where processing speed and parallelization are prioritized.
2Measurement precision
If multiple types of SAO information are coded with high precision arithmetic coding, then coding accuracy is improved, but bit stream length increases
Solution Approach 1:
The patent changes the coding parameters for different SAO information types. For first SAO information, it uses context adaptive binary arithmetic coding with variable probability values adapted to local characteristics. For second SAO information, it uses bypass arithmetic coding with fixed probability values (typically 0.5), which reduces the number of bits required while maintaining sufficient precision for the specific data characteristics.
3Measurement precision
If complex arithmetic coding processes are applied to all SAO data, then decoding accuracy is improved, but decoding complexity increases
Solution Approach 1:
The patent segments the decoding process into two parallel paths: one for first SAO information using context adaptive binary arithmetic decoding with variable probability updates, and another for second SAO information using simple bypass arithmetic decoding with fixed probability values. This segmentation reduces the overall decoding complexity by applying simplified processing where high precision is not critical.
Solution Approach 2:
The patent applies different decoding quality levels to different SAO information types. High-precision context adaptive decoding is applied locally to first SAO information where accuracy is critical for image quality, while simplified fixed-probability decoding is applied locally to second SAO information where the computational overhead outweighs the precision benefits.
Data Source
AI summary
A moving picture coding method includes: performing context adaptive binary arithmetic coding in which a variable probability value is used, on first information among multiple types of sample adaptive offset (SAO) information used for SAO that is a process of assigning an offset value to a pixel value of a pixel included in an image generated by coding the input image; and continuously performing bypass arithmetic coding in which a fixed probability value is used, on second information and third information among the multiple types of the SAO information, wherein the coded second and third information are placed after the coded first information in the bit stream.