Select Back Microphone on iPhone 5

Question

Is there a way for RemoteIO unit to pick up back microphone on iPhone 5 ? I can configure AVAudioSession to choose between front microphone or bottom microphone but I can't find a way to select the back Microphone.

The AVFoundation framework for sure uses the back microphone for video recording when using the back camera, but I want a way to choose the same using CoreAudio. Is that possible ?

Hi Deepak Sharma could you please give me some idea or code to choose the front microphone or bottom microphone ? Thanks in advance — user247, Feb 27 '13 at 11:53
Hey Deepak, were you able to find the solution to this? If so would you mind sharing it? — OriginalAlchemist, Jan 30 '17 at 04:12

score 1 · Answer 1 · answered May 16 '13 at 08:15

Setting kAudioSessionProperty_Mode to kAudioSessionMode_VideoRecordingwith AudioSessionSetProperty uses the microphone nearest to the camera, which should be the back microphone. That's if you use the Audio Session Services. AVAudioSessionModeVideoRecordingif you're using AVFoundation to record. The doc says "Using this mode may result in the system providing appropriate audio signal processing." which I interpet as "we may also use the other mics for noise cancelling".

score 1 · Answer 2 · answered Oct 19 '13 at 06:42

Use AVAudioSession to get available inputs. On my iPhone 5 it looks like this.

NSLog(@"%@", [AVAudioSession sharedInstance].availableInputs);

  "<AVAudioSessionPortDescription: 0x14554400, type = MicrophoneBuiltIn; name = iPhone Microphone; UID = Built-In Microphone; selectedDataSource = Back>"

Then use one of these inputs to get availableDataSources, like this.

NSLog(@"%@", [AVAudioSession sharedInstance].availableInputs[0].dataSources);

  "<AVAudioSessionDataSourceDescription: 0x145afb00, ID = 1835216945; name = Bottom>",
  "<AVAudioSessionDataSourceDescription: 0x145b1870, ID = 1835216946; name = Front>",
  "<AVAudioSessionDataSourceDescription: 0x145b3650, ID = 1835216947; name = Back>"

Now you can set your preferred data source.

AVAudioSessionPortDescription *port = [AVAudioSession sharedInstance].availableInputs[0];
for (AVAudioSessionDataSourceDescription *source in port.dataSources) {
    if ([source.dataSourceName isEqualToString:@"Back"]) {
        [port setPreferredDataSource:source error:nil];
    }
}

Thank you. But this is supposed to only work on iOS 7 I believe. That is also okay I think. — Deepak Sharma, Nov 27 '13 at 07:14
what should be the category for using this code, for setting preferred datasource? — Shefali Soni, Sep 03 '14 at 03:15

Select Back Microphone on iPhone 5

2 Answers2