I've got an application that should record the downlink audio of a voice call. To be able to do this I've got to mute the microphone so that I only get the downlink audio and no environment noise.
The recording is done using CMdaAudioInputStream.
Mic muting was done using CPhCltCommandHandler for Symbian OS 9.1 and 9.2 (which avoided the audio from the mic to be forwarded to the uplink and to the recorder), but this does not work for OS 9.3.
I now found the CCallAudioControl class in the SDK API Plug-in CallAudioControlAPI that provides functionality to mute a call. Unfortunately this does only work partially: the uplink does not receive any audio from the mic anymore (which is OK), but the audio recorded on the device still contains the audio from the mic (which is not as expected). I've seen the same problem if I manually mute the microphone using the UI.
Selecting the audio to be recorded using CAudioInput::SetAudioInputL() of the SDK API Plug-in AudioRoutingAPI didn't work either.
Has anyone encountered the same problem and found a solution to it?
Oh, I forgot: The problem was found on N85 and N96, so it seams to be related to OS 9.3.
Help would be much appreciated!!