Hierarchical Audio Error Concealment Using Low-Delay Windows
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Solution Overview
Problem
Current hierarchical decoding systems face challenges in maintaining signal quality during low-delay transmission, as they cannot effectively utilize information from valid frames to generate missing samples for erased frames without introducing additional time delay, leading to reduced quality of decoded audio signals.
Innovation Solution
A method and device for concealing transmission errors in digital signals, which implement a hierarchical decoding system using low-delay windows, dividing the process into two time intervals for generating missing samples: the first set using previous frame information and the second set using valid frame information, with a transition step to ensure continuity and reduce computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If information from valid frames is used to generate missing samples for erased frames, then the quality of decoded audio signals is improved, but additional time delay is introduced
Solution Approach 1:
The patent segments the generation of missing samples into two distinct time intervals: a first time interval where a first set of missing samples is generated using previous frame information, and a second time interval where a second set of missing samples is generated using valid frame information. This segmentation allows the system to utilize improved quality techniques while managing time delay through structured processing phases.
Solution Approach 2:
The patent performs preliminary action by generating the first set of missing samples in advance during the first time interval before the valid frame information is fully processed. This preliminary generation ensures that some replacement samples are available immediately, reducing overall delay while still allowing for subsequent refinement using valid frame information.
2Loss of time
If a hierarchical decoding system uses low-delay windows, then transmission delay is reduced, but the ability to utilize valid frame information for error concealment is limited
Solution Approach 1:
The patent implements dynamic adaptation by adjusting the error concealment strategy based on the available time intervals and valid frame information. The system dynamically switches between using previous frame information (when time is constrained) and valid frame information (when more time is available), optimizing the balance between low delay and reliable error concealment.
Solution Approach 2:
The system performs preliminary error concealment actions using previous frame information in the first time interval, establishing a baseline reconstruction that maintains low delay. This preliminary action ensures that error concealment is already in progress before valid frame information becomes available, maximizing the utility of low-delay windows.
3Manufacturing precision
If missing samples are generated using valid frame information, then signal quality is improved, but computational load increases
Solution Approach 1:
The patent segments the computationally intensive sample generation process into two phases: a first phase using simpler previous frame information and a second phase using more complex valid frame information. This segmentation distributes computational load across different time intervals, preventing peak overload while still achieving high signal quality through the second phase refinement.
Solution Approach 2:
The patent applies partial action by generating only a second set of missing samples (rather than all samples) using the computationally intensive valid frame information. This partial application of the complex algorithm reduces overall computational load while still improving signal quality for the most critical portions of the erased frame.
Data Source
AI summary
A method is provided for concealing a transmission error in a digital signal chopped into a plurality of successive frames associated with different time intervals in which, on reception, the signal may comprise erased frames and valid frames, the valid frames comprising information relating to the concealment of frame loss. The method is implemented during a hierarchical decoding using a core decoding and a transform-based decoding using windows introducing a time delay of less than a frame with respect to the core decoding. The method includes concealing a first set of missing samples for the erased frame, implemented in a first time interval; a step of concealing a second set of missing samples utilizing information of said valid frame and implemented in a second time interval; and a step of transition between the first and the second set of missing samples to obtain at least part of the missing frame.