[Speex-dev] 2 weeks lost in the AEC world

[jesus]

Hi,

my VoIP system uses speex with framesize = 160 samples(20 ms) at 8khz, 
sending and receiving paquets of 1600 samples(200 ms).

When I receive a packet, I buffered it (I have also tried with 
speex_echo_playback) before sending to the speaker.

When I capture from microphone, I fist remove DC offset (I saw in OPAL 
sources) and then I call speex_echo_cancellation for every one of the 10 
"minipackets" (I have also tried to pass the entire 1600 samples packet 
but it produces heap corruption).
I play with a DELAY(in ms) over the playback buffer, and tried a lot of  
different tail lenght.

I have not obtained any minimal result of echo cancellation.

Please, if anybody has tested AEC on a VoIP system, any suggestion will 
be wellcomed.


the code seems like this:

void ComprimeSpeex::CancelarEco(short *buffer, int tam)
{
    wxMutexLocker lock(mx_eco_state);

    if(ecosize >= tam+DELAY*8*2) // pass delay(milliseconds) to bytes
    {
        short *eco = (short*)bufeco+ecosize-tam-DELAY*8; // take from 
the last 10 frames - delay

// pass entire packet --> heap corruption
//        speex_echo_cancellation(echo_state, (short*)buffer, eco, 
(short*)salida);

// pass each 20 ms packet
        for(int i=0;i<1600;i+=160)
        {
            speex_echo_cancellation(echo_state, (short*)buffer+i, eco+i, 
(short*)salida+i);
        }

        // manage the buffer
        ecosize -= tam;
        if(ecosize > 0)
            memmove(bufeco, bufeco+tam, ecosize);
        // return the result buffer
        memcpy(buffer, salida, tam);
    }
    else
        ecosize = 0;
}