Layered Audio Bit Stream Seeking with Partial Decoding
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Solution Overview
Problem
Existing methods for seeking in layered audio bit streams with different access points struggle to balance seeking accuracy, audio reproduction quality, playback latency, and processing power load, particularly in layered formats where higher layers have fewer entry points than the base layer.
Innovation Solution
The method involves starting partial decoding of the enhancement layer from an entry point prior to the desired base layer entry point, followed by re-synchronization of the enhancement layer data, and then decoding both layers from the next base layer entry point, allowing for full-quality audio output while managing latency and processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If seeking is performed in enhancement layer from prior entry point followed by re-synchronization, then seeking accuracy is improved, but processing power load increases
Solution Approach 1:
The method performs partial decoding of the enhancement layer from an entry point prior to the desired base layer entry point before re-synchronization. This preliminary action prepares the enhancement layer data in advance, enabling more accurate seeking while managing processing load through controlled partial processing rather than full decoding
Solution Approach 2:
The patent applies partial decoding to the enhancement layer - decoding only the necessary portion from the prior entry point up to the re-synchronization point, rather than full decoding of the entire enhancement layer. This partial action achieves sufficient seeking accuracy while limiting the processing power load to only what is necessary for the seeking operation
2Measurement precision
If partial decoding of enhancement layer is performed prior to desired entry point, then seeking precision is improved, but playback latency increases
Solution Approach 1:
The enhancement layer is partially decoded in advance from a prior entry point before the desired playback position. This preliminary decoding action prepares the data ahead of time, improving seeking precision while the subsequent re-synchronization step ensures that only the necessary time delay is incurred, minimizing overall playback latency
3Manufacturing precision
If re-synchronization of enhancement layer is performed, then audio quality is improved, but processing complexity increases
Solution Approach 1:
The decoding process is segmented into distinct phases: partial decoding of the enhancement layer from a prior entry point, re-synchronization at the desired base layer entry point, and then full decoding. This segmentation allows the system to manage complexity by handling only necessary portions at each stage rather than processing everything simultaneously
Solution Approach 2:
Instead of fully decoding and re-synchronizing the entire enhancement layer, the patent performs partial decoding only up to the re-synchronization point. This partial action achieves the necessary audio quality improvement while significantly reducing processing complexity compared to complete re-decoding
4Quantity of substance
If enhancement layer has fewer entry points than base layer, then data rate is reduced, but seeking capability deteriorates
Solution Approach 1:
The method uses the limited enhancement layer entry points efficiently by performing partial decoding from the prior entry point to the desired position. This preliminary action compensates for the fewer entry points, enabling seeking capability to function effectively even with reduced data rate and fewer enhancement layer access points
Solution Approach 2:
The base layer entry points serve as intermediaries that bridge the gap between the fewer enhancement layer entry points and the desired seeking positions. By combining base layer entry point information with partial enhancement layer decoding, the system achieves effective seeking capability despite the enhancement layer having fewer direct entry points
Data Source
AI summary
A two-layer hierarchical audio bit stream can have a frame-based structure for the base layer bit stream and can be decoded independently from a higher layer and the decoding can start following every sync header. In the extension layer bit stream the frame structure may not be reflected on bit stream level. To facilitate seek operations with such highly compressed extension-layer data, the header of the extension layer bit stream comprises an FAT table with seek target positions. Because there are fewer entry points in the enhancement layer than sync headers in the base layer, a re-synchronization and some base layer frames are required to start decoding of the enhancement layer and to generate the full audio quality. Three seeking ways of seeking are described, of which each one offers a different compromise between seeking accuracy, re-synchronization latency and audio quality.