How to select bottom microphone for IOS video app? - ios

Question

I found this sample code online: https://developer.apple.com/library/content/samplecode/AVCam/Introduction/Intro.html
I am trying to change the input microphone from the default microphone to the bottom microphone on an iPhone. Does anyone have any experience going about this in Swift? The only examples I've found were in Obj-C and caused errors when I implemented them. I'm using apple's AVCam sample app for reference, the audio part is included below.
// Add audio input.
do {
let audioDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeAudio)
let audioDeviceInput = try AVCaptureDeviceInput(device: audioDevice)
if session.canAddInput(audioDeviceInput) {
session.addInput(audioDeviceInput)
}
else {
print("Could not add audio device input to the session")
}
}
catch {
print("Could not create audio device input: \(error)")
}

Answer 1

You should try settings the category of the session using:
session.setCategory(AVAudioSessionCategoryPlayAndRecord, withOptions: AVAudioSessionCategoryOptions.DefaultToSpeaker, error: nil)
this should make use the bottom microphone by default

Answer 2

If you only need audio you should use AVAudioSession - https://developer.apple.com/reference/avfoundation/avaudiosession
Not tested Sample code you could play around with:
import AVFoundation
.
.
private var session: AVAudioSession!
private var input: AVAudioSessionPortDescription!
.
.
.
session = AVAudioSession.sharedInstance()
do {
try session.setCategory(AVAudioSessionCategoryRecord)
// Fetch Built in Mic
if let availableInputs = session.availableInputs {
for inputSource in availableInputs {
if inputSource.portType == AVAudioSessionPortBuiltInMic {
input = inputSource
break
}
}
// Set preferred data source by location
if let dataSources = input.dataSources {
for dataSource in dataSources {
if dataSource.location == AVAudioSessionLocationLower {
input.setPreferredDataSource(dataSource)
break
}
}
}
session.setPreferredInput(input)
.
.
} catch {
....
}