Speex echo cancellation configuration

Question

I am making an Android-to-Android VoIP (loudspeaker) app using its AudioRecord and AudioTrack class, along with Speex via NDK to do echo cancellation. I was able to successf

Answer 1

Are you properly aligning the far-end signal (what you call recv) and near end signal (what you call record)? There is always some playback/record latency which needs to be accounted for. This generally requires buffering of the far-end signal in a ring buffer for some specified period of time. On PCs this is usually about 50 - 120ms. On Android I suspect it's much higher. Probably in the range of 150 - 400ms. I would recommend using a 100ms taillength with speex and adjusting the size of your far-end buffer until the AEC converges. These changes should allow the AEC to converge, independently of the inclusion of the preprocessor, which is not required here.