Output Layer Set Indexing in Video Decoding
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Solution Overview
Problem
Current video coding standards, such as MV-HEVC and SHVC, face challenges in identifying the correct layers to be output during decoding, leading to inefficiencies in decoding processes and potential instability in session initialization due to mismatched output layer sets and target layers.
Innovation Solution
The proposed solution involves deriving an index to a specific target output layer set and using it to define the set of target output layers during decoding, along with duplicating output operation points in transport layer specifications for session negotiation, allowing for efficient extraction of sub-bitstreams based on temporal and spatial scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current video coding standards (MV-HEVC, SHVC) are used for multi-layer decoding, then spatial and temporal scalability are achieved, but identification of correct output layers becomes inefficient and unstable
Solution Approach 1:
The patent introduces an intermediary data structure called 'output layer set' that acts as a mediator between the coded video data and the decoding process. This output layer set contains explicit identification information about which layers should be output, resolving the ambiguity in current standards. The intermediary structure stabilizes session initialization by providing clear, unambiguous layer identification without increasing decoder complexity.
Solution Approach 2:
The patent segments the layer identification process into distinct components: the output layer set definition, the target layer identification, and the decoding output control. By separating these functions, the patent makes the layer identification process more manageable and reliable, allowing the system to clearly distinguish between layers that should be decoded and layers that should be output.
2Productivity
If all layers are decoded and output in multi-layer video coding, then complete video information is preserved, but data consumption and processing overhead increase
Solution Approach 1:
The patent extracts only the necessary layers for output from the complete multi-layer bitstream. By using the output layer set to identify which layers should be output, the system can skip processing and outputting unnecessary layers, thereby improving decoding efficiency and reducing data consumption while preserving all necessary video information.
Solution Approach 2:
The patent applies partial action by decoding all layers (to maintain scalability and reference functionality) but outputting only the specified subset of layers. This approach maintains the benefits of full decoding for reference purposes while reducing the actual output data volume to only what is needed, optimizing the balance between processing completeness and output efficiency.
3Measurement precision
If target output layer set is explicitly defined in bitstream, then output layer identification accuracy improves, but bitstream size and signaling overhead increase
Solution Approach 1:
The patent changes the parameter representation by using an index to reference pre-defined output layer sets rather than explicitly signaling each layer configuration. This parameter change maintains accurate layer identification while reducing signaling overhead, as the index refers to previously established layer set definitions in the bitstream.
Solution Approach 2:
The patent performs preliminary action by pre-defining output layer sets with their specific layer configurations before the actual decoding process. These pre-defined sets are stored in the bitstream with indices, allowing efficient reference during decoding without repeating full layer specifications, thus improving identification accuracy while minimizing signaling overhead.
Data Source
AI summary
A method, apparatus, and manufacture for processing video data. A list of output layer sets in a video bitstream is received, and an index to at least one target output layer set in the list of output layer sets is received. Next, target output layers in the at least one target output layer set is determined based on the index. At least the target output layers from the video bitstream are decoded. Then, the decoded target output layers are output without outputting layers that are not targeted for output.