Acoustic Echo Cancellation Using Encoded Audio Reference Signals
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Solution Overview
Problem
Current lossy audio encoding schemes used in short-range wireless protocols, such as Bluetooth, introduce artifacts in decoded audio signals that interfere with echo cancellation, making it difficult for systems like keyword detection and automatic speech recognition to accurately process voice inputs.
Innovation Solution
An apparatus and method that include an encoder, decoder, and echo canceler to produce an echo-cancelled voice signal by reducing the energy of signal components based on audio content from the encoded media signal, using techniques like least-mean-squares algorithms and double-talk detection, to improve acoustic echo cancellation and reduce artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lossy audio encoding is used for wireless transmission, then bandwidth efficiency is improved, but artifacts are introduced that interfere with echo cancellation
Solution Approach 1:
The system performs preliminary action by generating an echo reference signal from the encoded media signal before echo cancellation is needed. This allows the echo canceller to have advance knowledge of the encoded audio content, enabling it to effectively subtract the echo component from the microphone signal even in the presence of lossy encoding artifacts.
Solution Approach 2:
The echo reference signal acts as an intermediary that bridges the encoded media signal and the microphone signal. By introducing this intermediate representation of the echo path output, the system can perform accurate echo cancellation without being directly affected by the artifacts in the original encoded signal.
2Object-generated harmful factors
If acoustic echo cancellation is performed on microphone signals during audio playback, then echo interference is reduced, but voice signal quality may be degraded
Solution Approach 1:
The system uses feedback by continuously monitoring the encoded media signal and using it to generate an updated echo reference signal. This feedback loop allows the echo canceller to adapt to changes in the audio playback content in real-time, maintaining high echo cancellation performance while preserving voice signal integrity.
Solution Approach 2:
The echo canceller dynamically adjusts its processing parameters based on the encoded media signal characteristics. By changing parameters such as the echo reference signal generation method and cancellation depth, the system optimizes the balance between echo removal and voice quality preservation under different playback conditions.
Data Source
AI summary
Methods, systems, computer-readable media, and apparatuses for acoustic echo cancellation during playback of encoded audio are presented. In some embodiments, a decoder is arranged to decode an encoded media signal to produce an echo reference signal, and an echo canceler is arranged to perform an acoustic echo cancellation operation, based on the echo reference signal, on an input voice signal to produce an echo-cancelled voice signal. The echo canceler may be configured to reduce, relative to an energy of a voice component of the input voice signal, an energy of a signal component of the input voice signal that is based on audio content from the encoded media signal.