Video Decoder Access Unit Delimiter Parameter Segmentation
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Solution Overview
Problem
In low-delay video coding environments, the use of Adaptive Loop Filter (ALF) is hindered because the Adaptation Parameter Set (APS) with filter parameters must be sent before the first slice of the picture, causing delays and making it difficult for decoders to determine if all necessary parameter sets are available for decoding.
Innovation Solution
A video decoder is configured to derive necessary parameters from the access unit, allowing it to start decoding before receiving all video coding units of a picture by reading in-loop filter control information from parameter sets within the access unit, reducing decoding delay and enabling efficient parameter set identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the APS with filter parameters is sent before the first slice of the picture, then the ALF can be applied to improve video quality, but the decoding delay increases and the decoder cannot start decoding early
Solution Approach 1:
The patent divides the parameter set delivery into two parts: necessary parameters are included in the access unit delimiter (AUD) for immediate use, while complete or updated parameters follow later in the bitstream. This segmentation allows the decoder to start processing early with essential parameters while receiving full parameter sets subsequently.
Solution Approach 2:
The patent places essential ALF parameters in the access unit delimiter (AUD) before the video coding units, enabling the decoder to perform preliminary filtering operations immediately upon receiving the AUD without waiting for the complete parameter sets that would normally follow later in the bitstream.
2Reliability
If the decoder waits to receive all parameter sets before decoding, then all necessary parameters are available for accurate decoding, but the decoding speed decreases
Solution Approach 1:
The patent segments parameter set delivery by placing essential parameters in the access unit delimiter (AUD) and complete/updated parameters in subsequent Adaptation Parameter Sets. This allows the decoder to proceed with decoding using essential parameters from the AUD while receiving complete parameter sets without blocking the decoding process.
Solution Approach 2:
The access unit delimiter (AUD) acts as an intermediary that carries essential ALF parameters to the decoder before the complete parameter sets are available. This intermediary structure enables the decoder to obtain necessary filtering parameters immediately without waiting for the full parameter set transmission.
3Ease of operation
If the APS is sent early before slices, then filter parameters are available for ALF application, but the encoder cannot start sending processed parts early in low-delay environments
Solution Approach 1:
The patent segments the parameter transmission by placing essential ALF parameters in the access unit delimiter (AUD) that precedes the video coding units, while complete or updated parameters are transmitted in subsequent Adaptation Parameter Sets. This allows the encoder to send immediately usable parameters early without waiting for complete parameter set generation.
Solution Approach 2:
The encoder performs preliminary action by placing essential ALF parameters in the access unit delimiter (AUD) before encoding complete pictures, enabling the decoder to apply filtering operations early in the decoding process without requiring the encoder to complete full picture encoding first.
Data Source
AI summary
A video decoding configured to read one or more video coding layer network abstraction layer units, VCL NAL units, within an access unit, AU, in a video data stream; generate a reconstructed version of a decoded picture from the one or more VCL NAL units; read an adaptive loop filter adaptive parameter set, ALF APS, the ALF APS being a suffix adaptive parameter set network abstraction layer unit type, APS NAL unit type, and the suffix APS NAL unit type indicating that the ALF APS follows the one or more VCL NAL units within the AU; and perform adaptive loop filtering on the reconstructed version of the decoded picture in a manner depending on one or more coefficients comprised by the ALF APS.