Forcing iPhone Microphone as Audio Input

Question

I am developing an iOS application (targetted specifically for iPhone, at the moment) that requires the application to record audio only from iPhone internal microph

Answer 1

Since apple changed the audio system again starting from 7.0 I'm going to post the update-ed code over here:

#pragma mark Route change listener
// *********************************************************************************************************
// *********** Route change listener ***********************************************************************
// *********************************************************************************************************
-(void)routeChanged:(NSNotification*)notification {

    NSLog(@"]-----------------[ Audio Route Change ]--------------------[");

    AVAudioSession *session = [AVAudioSession sharedInstance];

    //AVAudioSessionRouteDescription* prevRoute = [[notification userInfo] objectForKey:AVAudioSessionRouteChangePreviousRouteKey];

    // Reason
    NSInteger reason = [[[notification userInfo] objectForKey:AVAudioSessionRouteChangeReasonKey] integerValue];
    switch (reason) {
        case AVAudioSessionRouteChangeReasonNoSuitableRouteForCategory:
            NSLog(@"] Audio Route: The route changed because no suitable route is now available for the specified category.");
            break;
        case AVAudioSessionRouteChangeReasonWakeFromSleep:
            NSLog(@"] Audio Route: The route changed when the device woke up from sleep.");
            break;
        case AVAudioSessionRouteChangeReasonOverride:
            NSLog(@"] Audio Route: The output route was overridden by the app.");
            break;
        case AVAudioSessionRouteChangeReasonCategoryChange:
            NSLog(@"] Audio Route: The category of the session object changed.");
            break;
        case AVAudioSessionRouteChangeReasonOldDeviceUnavailable:
            NSLog(@"] Audio Route: The previous audio output path is no longer available.");
            break;
        case AVAudioSessionRouteChangeReasonNewDeviceAvailable:
            NSLog(@"] Audio Route: A preferred new audio output path is now available.");
            break;
        case AVAudioSessionRouteChangeReasonUnknown:
            NSLog(@"] Audio Route: The reason for the change is unknown.");
            break;
        default:
            NSLog(@"] Audio Route: The reason for the change is very unknown.");
            break;
    }

    // Output
    AVAudioSessionPortDescription *output = [[session.currentRoute.outputs count]?session.currentRoute.outputs:nil objectAtIndex:0];
    if ([output.portType isEqualToString:AVAudioSessionPortLineOut]) {
        NSLog(@"] Audio Route: Output Port: LineOut");
    }
    else if ([output.portType isEqualToString:AVAudioSessionPortHeadphones]) {
        NSLog(@"] Audio Route: Output Port: Headphones");
    }
    else if ([output.portType isEqualToString:AVAudioSessionPortBluetoothA2DP]) {
        NSLog(@"] Audio Route: Output Port: BluetoothA2DP");
    }
    else if ([output.portType isEqualToString:AVAudioSessionPortBuiltInReceiver]) {
        NSLog(@"] Audio Route: Output Port: BuiltInReceiver");
    }
    else if ([output.portType isEqualToString:AVAudioSessionPortBuiltInSpeaker]) {
        NSLog(@"] Audio Route: Output Port: BuiltInSpeaker");
    }
    else if ([output.portType isEqualToString:AVAudioSessionPortHDMI]) {
        NSLog(@"] Audio Route: Output Port: HDMI");
    }
    else if ([output.portType isEqualToString:AVAudioSessionPortAirPlay]) {
        NSLog(@"] Audio Route: Output Port: AirPlay");
    }
    else if ([output.portType isEqualToString:AVAudioSessionPortBluetoothLE]) {
        NSLog(@"] Audio Route: Output Port: BluetoothLE");
    }
    else {
        NSLog(@"] Audio Route: Output Port: Unknown: %@",output.portType);
    }

    // Input
    AVAudioSessionPortDescription *input = [[session.currentRoute.inputs count] ? session.currentRoute.inputs:nil objectAtIndex:0];

    if ([input.portType isEqualToString:AVAudioSessionPortLineIn]) {
        NSLog(@"] Audio Route: Input Port: LineIn");
    }
    else if ([input.portType isEqualToString:AVAudioSessionPortBuiltInMic]) {
        NSLog(@"] Audio Route: Input Port: BuiltInMic");
    }
    else if ([input.portType isEqualToString:AVAudioSessionPortHeadsetMic]) {
        NSLog(@"] Audio Route: Input Port: HeadsetMic");
    }
    else if ([input.portType isEqualToString:AVAudioSessionPortBluetoothHFP]) {
        NSLog(@"] Audio Route: Input Port: BluetoothHFP");
    }
    else if ([input.portType isEqualToString:AVAudioSessionPortUSBAudio]) {
        NSLog(@"] Audio Route: Input Port: USBAudio");
    }
    else if ([input.portType isEqualToString:AVAudioSessionPortCarAudio]) {
        NSLog(@"] Audio Route: Input Port: CarAudio");
    }
    else {
        NSLog(@"] Audio Input Port: Unknown: %@",input.portType);
    }

    NSLog(@"]--------------------------[  ]-----------------------------[");

}

Remember to add observer since the audio session's delegate is deprecated too:

[[NSNotificationCenter defaultCenter] addObserver: self
                                                 selector: @selector(audioInterruption:)
                                                     name: AVAudioSessionInterruptionNotification
                                                   object: nil];

PS: you dont need to reset the category here (as in 6.0)