I can't record using AVAudioEngine - ios

Question

AVAudioSession.sharedInstance().setCategory(.playAndRecord, mode: .default)
I can record using the above code.
However, during playback, only the speakers at the top of the iPhone produce sound.
So I would like to add defaultToSpeaker to options.
However, adding it does not record.
Is there a solution?
Please help me.
Here is the code I wrote.
final class RecordEngine {
private var engine: AVAudioEngine!
private var mixer: AVAudioMixerNode!
private var player: AVAudioPlayerNode!
private var outputFile: AVAudioFile!
let session = AVAudioSession.sharedInstance()
init() {
prepareAVAudioSession()
prepareNodes()
prepare()
}
func start() {
try! engine.start()
}
func stop() {
engine.pause()
engine.reset()
}
private func prepareAVAudioSession() {
do {
// try session.setCategory(.playAndRecord, mode: .default, options: [.allowBluetooth, .allowBluetoothA2DP])
try session.setCategory(.playAndRecord, mode: .default, options: .defaultToSpeaker)
try session.setActive(true)
} catch {
}
}
private func prepareNodes() {
engine = AVAudioEngine()
mixer = AVAudioMixerNode()
player = AVAudioPlayerNode()
engine.attach(mixer)
engine.attach(player)
}
private func prepare() {
let input = engine.inputNode
let mainMixer = engine.mainMixerNode
let format = input.outputFormat(forBus: 0)
engine.connect(player, to: mainMixer, format: format)
engine.connect(input, to: mixer, format: format)
engine.prepare()
}
func startRecord() {
start()
let format = mixer.outputFormat(forBus: 0)
let outputFileURL = URL(string: NSTemporaryDirectory() + "temp.caf")!
do {
outputFile = try AVAudioFile(forWriting: outputFileURL, settings: format.settings)
} catch {
print(error)
}
mixer.installTap(onBus: 0, bufferSize: 1024, format: format) { [weak self] buffer, when in
do {
try self?.outputFile.write(from: buffer)
print(buffer)
} catch {
print(error)
}
}
}
func stopRecord() {
mixer.removeTap(onBus: 0)
print(outputFile)
stop()
}
func startPlaying() {
start()
player.scheduleFile(outputFile, at: nil) {
print("complete")
}
player.play()
}
func pausePlaying() {
player.pause()
}
}

Answer 1

The problem isn't defaultToSpeaker but rather the mixer setup. You've got a mixer (that you install a tap on) with no output and also mainMixerNode.
Do you need both mixers? If so, you could connect mixer to mainMixer:
engine.connect(mixer, to: mainMixer, format: format)
or remove mixer and use mainMixer everywhere, or some 3rd option that doesn't produce feedback.