Redirecting audio output to phone speaker and mic input to headphones

Question

Is it possible to redirect audio output to the phone speaker and still use the microphone headphone input?

If i redirect the audio route to the phone speaker instead of the headphones it also redirects the mic. This makes sense but I can't seem to just be able to just redirect the mic input? Any ideas?

Here is the code I'm using to redirect audio to the speaker:

UInt32 doChangeDefaultRoute = true;        
propertySetError = AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryDefaultToSpeaker, sizeof(doChangeDefaultRoute), &doChangeDefaultRoute);
NSAssert(propertySetError == 0, @"Failed to set audio session property: OverrideCategoryDefaultToSpeaker");
UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;
AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,sizeof (audioRouteOverride),&audioRouteOverride);

Answer 1

This is possible, but it's picky about how you set it up.

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;
AudioSessionSetProperty(kAudioSessionProperty_OverrideAudioRoute, sizeof(audioRouteOverride), &audioRouteOverride);

It's very important to use AVAudioSessionCategoryPlayAndRecord or the route will fail to go to the speaker. Once you've set the override route for the audio session, you can use an AVAudioPlayer instance and send some output to the speaker.

Hope that works for others like it did for me. The documentation on this is scattered, but the Skype app proves it's possible. Persevere, my friends! :)

Some Apple documentation here: http://developer.apple.com/library/ios/#documentation/AudioToolbox/Reference/AudioSessionServicesReference/Reference/reference.html

Do a search on the page for kAudioSessionProperty_OverrideAudioRoute