Audio Error Concealment Fade-Out Across Switched Coding Domains
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Solution Overview
Problem
Current audio signal encoding and decoding technologies face challenges in effectively managing signal fade-out during error concealment in switched audio coding systems, particularly in maintaining a pleasant noise characteristic and avoiding computational complexity during burst packet losses.
Innovation Solution
An apparatus and method for improved signal fade-out in switched audio coding systems, which involves tracing noise levels in the excitation domain and fading to a comfort noise level, ensuring a common noise level is targeted during burst packet losses, and using a correction factor to adjust levels between domains, thereby reducing computational complexity and maintaining a pleasant noise characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If independent noise level tracing modules are used for each coding mode, then noise level tracing accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple noise level tracing operations into a single unified tracing module that handles both ACELP and TCX coding modes. This is achieved by transforming noise level information from different domains (excitation domain for ACELP, time domain for TCX) to a common tracing domain, allowing one module to serve multiple coding modes without sacrificing tracing accuracy.
Solution Approach 2:
The patent introduces a transform unit as an intermediary that converts noise level information from various coding domains to a common tracing domain. This mediator enables the single noise level tracing module to process and compare noise levels from different coding modes accurately, resolving the contradiction between using independent modules and maintaining accuracy.
2Measurement precision
If noise level tracing is performed in multiple domains, then tracing accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent transforms noise level information from different domains (excitation domain, time domain) to a common tracing domain through transform units. This dimensional transformation allows accurate multi-domain tracing to be performed by a single module, reducing computational complexity while maintaining tracing accuracy across different coding modes.
3Reliability
If signal fade-out is performed during error concealment, then signal quality is improved, but noise characteristic pleasantness may deteriorate
Solution Approach 1:
The patent applies different fade-out strategies to different signal components based on their characteristics. Voiced segments use one fade-out approach while unvoiced segments use another, allowing the system to maintain pleasant noise characteristics in unvoiced regions while ensuring signal quality through appropriate fade-out in voiced regions during error concealment.
Data Source
AI summary
An apparatus for decoding an audio signal is provided, having a receiving interface, configured to receive a first frame having a first audio signal portion of the audio signal, and configured to receive a second frame having a second audio signal portion of the audio signal; a noise level tracing unit, wherein the noise level tracing unit is configured to determine noise level information depending on at least one of the first audio signal portion and the second audio signal portion; a first reconstruction unit for reconstructing, in a first reconstruction domain, a third audio signal portion of the audio signal depending on the noise level information; a transform unit for transforming the noise level information to a second reconstruction domain; and a second reconstruction unit for reconstructing, in the second reconstruction domain, a fourth audio signal portion of the audio signal depending on the noise level information.