使用 AVAudioRecorder 录制后，AVAudioPlayer 不通过扬声器播放

Question

I'm working on an app that does audio recording and playback of recorded audio. I'm using AVAudioSession to change the category to playAndRecord as well as passing it to defaultToSpeaker .

My problem is , if I launch the app, play an earlier recording, it plays through the bottom (louder) speaker as I want it to and expected BUT if I launch the app and start recording a new memo then play it back, no matter what I do, it will always use the quieter (phone call) speaker that's next to front face camera. I need it to play from the louder speaker (actually all speakers if possible).

NOTE: I'm running iOS 14.2.1, my phone is set to silent mode (usually) though I tried other settings as well. I'm testing on an iPhone 12. Ideally, I'm not really looking for a 3rd party SDK or library solution as I want the playback to be simple and done natively.

This is how I set the audioSession in my viewModel (that's initialized from a viewController):

private func setupAudioSession() {
    do {
        let session = AVAudioSession.sharedInstance()
        try session.setCategory(.playAndRecord, options: [.defaultToSpeaker, .allowBluetooth])
        try session.setActive(true)
        session.requestRecordPermission({ [weak self] allowed in
            guard let self = self else { return }
            if allowed == false {
                self.settingsAlert?()
            }
        })
    } catch {
        debugPrint("error setting up AVAudioSession")
    }
}

This is how I do recording:

func startRecording() {
    guard let audioFileDir = getAudioFilePath(songId: songModel!.id) else { return }
    let audioURLString = audioFileDir.absoluteString + ".m4a"
    guard let audioURL = URL(string: audioURLString) else { return }
    let recordingSettings: [String: Any] = [
        AVFormatIDKey: Int(kAudioFormatLinearPCM),
        AVLinearPCMIsNonInterleaved: false,
        AVSampleRateKey: 44_100.0,
        AVNumberOfChannelsKey: isStereoSupported ? 2 : 1,
        AVLinearPCMBitDepthKey: 16
    ]
    do {
        audioRecorder = try AVAudioRecorder(url: audioURL, settings: recordingSettings)
        audioUrl = audioURL
        audioRecorder?.delegate = self
        audioRecorder?.prepareToRecord()
        audioRecorder?.record()
    } catch {
        audioRecorder = nil
        debugPrint("Problem recording audio: \(error.localizedDescription)")
    }
}

I even included some code from WWDC 2020 for stereo recording and that's what isStereoSupported does.

And this is how I do playback

do {
    if let data = songDoc?.data?.audioData {
        audioPlayer = try AVAudioPlayer(data: data)
    } else if let url = audioUrl {
        audioPlayer = try AVAudioPlayer(contentsOf: url)
    }
    audioPlayer?.delegate = self
    audioPlayer?.play()
    isPlaying = true
} catch {
    audioPlayer = nil
    debugPrint("playback error: \(error.localizedDescription)")
}

Of course I have tried adding things like:

try session.overrideOutputAudioPort(AVAudioSession.PortOverride.speaker)

as well as setting the AVAudioSession each time I play or record. I've tried bunch of other similar things to fix this issue but nothing seems to work.

Answer 1

You should set audio session mode to AVAudioSessionModeVideoRecording and set session category options to AVAudioSessionCategoryOptionDefaultToSpeaker

[session setMode:AVAudioSessionModeVideoRecording error:&e]