LCU-Based SAO Signaling for Low-Latency Video Encoding
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Solution Overview
Problem
The existing HEVC standard's SAO parameter signaling method incurs delays and increased memory requirements due to encoding SAO parameters on a slice basis, which requires signaling LCU region partition information for each picture, leading to inefficient processing and storage demands.
Innovation Solution
The proposed solution involves signaling SAO parameters on an LCU basis, interleaving SAO information with LCU data in the encoded bit stream, and using prediction protocols to reduce the number of bits encoded, thereby eliminating the need for signaling region partitioning of a picture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If SAO parameters are signaled on a slice basis, then complete picture coverage is achieved, but processing delays and memory requirements increase
Solution Approach 1:
The patent segments SAO parameter signaling from the slice-based structure to an LCU-based structure. By dividing the picture into LCUs and signaling SAO parameters individually for each LCU, the patent enables incremental processing as each LCU is decoded, eliminating the need to wait for complete slice processing and reducing memory requirements for storing pending SAO parameters.
Solution Approach 2:
The patent applies preliminary action by signaling SAO parameters for each LCU immediately when that LCU is decoded, rather than waiting for slice-level processing. This allows the SAO filtering to be performed as soon as the necessary data is available, reducing processing delays and enabling immediate filtering operations without accumulating data in memory.
2Productivity
If SAO parameters are signaled on a slice basis, then region partition information is provided, but bit stream complexity and processing overhead increase
Solution Approach 1:
The patent extracts SAO parameter signaling from the slice-based structure and integrates it directly with LCU data in the bit stream. By taking out the SAO parameter signaling from the slice-level hierarchy and placing it at the LCU level, the patent simplifies the processing flow and reduces the complexity of managing region partition information separately.
Solution Approach 2:
The patent merges SAO parameter signaling with LCU data signaling in the bit stream. By combining these elements at the LCU level rather than maintaining separate slice-level and LCU-level structures, the patent reduces processing overhead and simplifies the bit stream structure, improving overall processing efficiency.
3Productivity
If SAO parameters are signaled for each LCU, then processing efficiency improves, but bit stream length increases
Solution Approach 1:
The patent applies parameter changes by using prediction protocols that reference previously decoded LCUs. Instead of signaling complete SAO parameter sets for every LCU, the patent changes the signaling approach to transmit only differential or predictive parameters, significantly reducing the bit stream length while maintaining processing efficiency.
Solution Approach 2:
The patent uses copying by referencing SAO parameters from previously decoded LCUs. Rather than encoding full parameter sets repeatedly, the patent copies parameter information from neighboring or previously processed LCUs and transmits only the differences or updates, reducing bit stream size while preserving processing efficiency.
Data Source
AI summary
A method for sample adaptive offset (SAO) filtering and SAO parameter signaling in a video encoder is provided that includes determining SAO parameters for largest coding units (LCUs) of a reconstructed picture, wherein the SAO parameters include an indicator of an SAO filter type and a plurality of SAO offsets, applying SAO filtering to the reconstructed picture according to the SAO parameters, and entropy encoding LCU specific SAO information for each LCU of the reconstructed picture in an encoded video bit stream, wherein the entropy encoded LCU specific SAO information for the LCUs is interleaved with entropy encoded data for the LCUs in the encoded video bit stream. Determining SAO parameters may include determining the LCU specific SAO information to be entropy encoded for each LCU according to an SAO prediction protocol.