Our VoipApplication uses the CVoipDownlink/UplinkStream API. If uplink and downlink are started simultaniously (EmptyBuffer delivers the recorded microfon audio and FillBuffer is filled by the recieved audio), there is some kind of noise or echo cancelling on the uplink stream.

A recorded white noise by the microfon has audio leaks between 0 and ~300ms and between ~350ms and 1s. Thereafter are no more leaks detected.

If I don't fill the downlink stream, there is no problem at all.

I tried this experiment on different phones, N8, C7, C701, E6, on Symbian and Belle, all over the same effect. Could this be a problem of a lack of ressources or needs the audio module some startup time to get ready?

This is a major problem if caller and callee starts speaking to the same time. The first words will become lost.

Is this a known issue of this API?

Best regards,