Music Detection for Echo Cancellation and Speech Coding
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Solution Overview
Problem
Conventional speech coding systems fail to differentiate between music and background noise, leading to poor quality music encoding and incorrect echo cancellation, as they often classify music signals as background noise due to their stability characteristics.
Innovation Solution
A method using music detection to enhance echo cancellation and speech coding, which involves an adaptive filter and a nonlinear processor, where a music detector determines the presence of music signals to bypass or attenuate accordingly, preventing degradation of music quality and improving perceptual quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voice activity detectors classify signals based on stability, then background noise can be differentiated from voice signals, but music signals are incorrectly classified as background noise due to their stability
Solution Approach 1:
The patent changes the detection parameters from simple stability-based classification to a multi-parameter analysis including spectral flatness, zero-crossing rate, and frame-to-frame correlation. This allows the system to distinguish music from background noise by detecting the characteristic stability patterns unique to each signal type.
Solution Approach 2:
The patent introduces a music detection module as an intermediary between the voice activity detector and the encoding system. This intermediary analyzes signal characteristics and provides classification information to prevent music signals from being incorrectly treated as background noise, thereby resolving the classification contradiction.
2Manufacturing precision
If noise suppressor attenuates error signal to suppress background noise, then speech quality improves, but music signal quality degrades due to unnecessary attenuation
Solution Approach 1:
The patent makes the noise suppressor dynamic by enabling or disabling it based on music detection results. When music is detected, the noise suppressor is disabled to prevent degradation of music quality. When background noise is detected, the noise suppressor is enabled to improve speech quality. This dynamic adaptation resolves the contradiction between noise suppression and music preservation.
3Reliability
If nonlinear processor eliminates echo signal components, then echo cancellation performance improves, but music signal is attenuated below noise floor
Solution Approach 1:
The patent dynamically controls the nonlinear processor based on music detection. When music is present in the error signal, the nonlinear processor is disabled to prevent attenuation of music components below the noise floor. When only background noise is present, the nonlinear processor operates to eliminate echo components. This dynamic control resolves the contradiction between echo cancellation and music signal preservation.
Data Source
AI summary
A method of using music detection to enhance an operation of an echo canceller is provided, wherein the echo canceller includes an adaptive filter and a nonlinear processor. The method comprises receiving an input signal including an echo signal by the echo canceller from a near end device, filtering the input signal using the adaptive filter to eliminate linear components of the echo signal in the input signal and generate an error signal, analyzing the error signal using a music detector to determine existence of a music signal in the error signal, bypassing the nonlinear processor if the analyzing determines the music signal exists in the error signal, and eliminating nonlinear components of the echo signal from the error signal using the nonlinear processor if the analyzing determines the music signal does not exist in the error signal.