Audio acoustic echo cancellation for video conferencing

摘要

A new audio echo cancellation (AEC) approach is disclosed. To facilitate echo cancellation, the method adjusts for errors (called drift) in sampling rates for both capturing audio and playing audio. This ensures that the AEC module receives both the signals at precisely the same sampling frequency. Furthermore, the far-end signal and near-end mixed signal are time aligned to ensure that the alignment is suitable for application of AEC techniques. An additional enhancement to reduce errors utilizes a concept of native frequency. A by-product of drift compensation allows for excellent buffer control for capture/playback and buffer overflow/underflow errors from drift errors are eliminated.

主权项

1. A method for audio acoustic echo cancellation in an audio conference with multiple participants, the audio conference implemented over a network, the method implemented at a participant's audio conference device connected to the network, the participant's audio conference device having a speaker and a microphone, the method comprising:
receiving a far-end audio signal effectively sampled at a nominal frequency fnom for the audio conference, the far-end audio signal originating from another audio conference device; playing back the far-end audio signal through the speaker; capturing a mixed signal through the microphone, the mixed signal containing an echo of the played back far-end audio signal, the mixed signal captured at a capture frequency fM; estimating a mismatch between the capture frequency fM and the nominal frequency fnom; adjusting the mixed signal to an effective sampling rate of fnom to compensate for the estimated mismatch; and applying audio acoustic echo cancellation to the far-end audio signal effectively sampled at fnom and the mixed signal effectively sampled at fnom.