Hi, I have a scenario in a mobile VoIP app that requires echo cancellation but is somewhat different from what's described in the docs. Audio is received from and sent to the network at 8000Hz. Each packet contains 160 samples worth a playback of 20ms. But the hardware requires aggregation for both playback and capture. So for playback, I coalesce 4 packets in a buffer and queue them as a larger buffer for playback. On the send side, I read a large buffer (worth 4 packets) and send them out over time 20ms apart. I tried using speex_echo_playback just when a 160-sample packet arrives from the network, before coalescing and speex_echo_capture just before a packet is sent out to the network but that doesn't seem to work properly (doesn't cancel any echo). So, in this scenario above, please recommend a good place to insert speex_echo_playback and speex_echo_capture. Should I be just before the read and write to hardware? In that case, should I use a larger "frame size" of 160 samples x 4? Thanks in advance, Daniel. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/speex-dev/attachments/20110415/f499b7d0/attachment.htm