AVAudioSession DefaultToSpeaker still playing audio from receiver - swift

Question

I have an app that allows users to playback audio while recording a video. They can only record in landscape.
This is how I've set up the playback of audio during a video session:
guard allowBackgroundAudio == true else {
return
}
guard audioEnabled == true else {
return
}
do{
if #available(iOS 10.0, *) {
try AVAudioSession.sharedInstance().setCategory(.playAndRecord, mode: .default, options: [.mixWithOthers, .defaultToSpeaker])
} else {
let options: [AVAudioSession.CategoryOptions] = [.mixWithOthers, .allowBluetooth]
let category = AVAudioSession.Category.playAndRecord
let selector = NSSelectorFromString("setCategory:withOptions:error:")
AVAudioSession.sharedInstance().perform(selector, with: category, with: options)
}
try AVAudioSession.sharedInstance().setActive(true)
session.automaticallyConfiguresApplicationAudioSession = false
}
catch {
print("[SwiftyCam]: Failed to set background audio preference")
}
}
The problem is audio is still playing slightly out of the receiver which means the top mic is picking up the audio playback, drowning out the user's audio.
After reading on here that the receiver speaker still playing might be a bug (or feature) from Apple I decided to use the back mic for the selfie camera, thus splitting the audio away from the mic. I can't seem to get the selfie camera to use the back mic.
public class func setMicrophone(_ uiorient: String) {
guard let inputs = AVAudioSession.sharedInstance().availableInputs else {
return
}
for input in inputs {
print(input.dataSources ?? "??")
}
// set preferred:
let preferredPort = inputs[0]
if let dataSources = preferredPort.dataSources {
for source in dataSources {
if source.dataSourceName == uiorient {
do {
try preferredPort.setPreferredDataSource(source)
}
catch _ {
print("Cannot set \(uiorient) microphone.")
}
}
}
}
}
and then have this when we are calling the selfie camera;
AudioRecorderViewController.setMicrophone("Back")