List All Available Audio Devices

List all available audio devices

If you want something like a actionSheet and need to switch between audio devices seamlessly. Use this code.

Code

import Foundation
import AVFoundation
import UIKit

@objc class AudioDeviceHandler: NSObject {
    
    @objc static let shared = AudioDeviceHandler()
    
    /// Present audio device selection alert
    /// - Parameters:
    ///   - presenterViewController: viewController where the alert need to present
    ///   - sourceView: alertController source view in case of iPad
    @objc func presentAudioOutput(_ presenterViewController : UIViewController, _ sourceView: UIView) {
        let speakerTitle = "Speaker"
        let headphoneTitle = "Headphones"
        let deviceTitle = (UIDevice.current.userInterfaceIdiom == .pad) ? "iPad" : "iPhone"
        let cancelTitle = "Cancel"
        
        var deviceAction = UIAlertAction()
        var headphonesExist = false
        let optionMenu = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
        
        guard let availableInputs = AVAudioSession.sharedInstance().availableInputs else {
            print("No inputs available ")
            return
        }
        
        for audioPort in availableInputs {
            switch audioPort.portType {
            case .bluetoothA2DP, .bluetoothHFP, .bluetoothLE :
                let bluetoothAction = UIAlertAction(title: audioPort.portName, style: .default) { _ in
                    self.setPreferredInput(port: audioPort)
                }
                
                if isCurrentOutput(portType: audioPort.portType) {
                    bluetoothAction.setValue(true, forKey: "checked")
                }
                
                optionMenu.addAction(bluetoothAction)
                
            case .builtInMic, .builtInReceiver:
                
                deviceAction = UIAlertAction(title: deviceTitle, style: .default, handler: { _ in
                    self.setToDevice(port: audioPort)
                })
                
            case .headphones, .headsetMic:
                headphonesExist = true
                
                let headphoneAction = UIAlertAction(title: headphoneTitle, style: .default) { _ in
                    self.setPreferredInput(port: audioPort)
                }
                
                if isCurrentOutput(portType: .headphones) || isCurrentOutput(portType: .headsetMic) {
                    headphoneAction.setValue(true, forKey: "checked")
                }
                
                optionMenu.addAction(headphoneAction)
                
            case .carAudio:
                let carAction = UIAlertAction(title: audioPort.portName, style: .default) { _ in
                    self.setPreferredInput(port: audioPort)
                }
                
                if isCurrentOutput(portType: audioPort.portType) {
                    carAction.setValue(true, forKey: "checked")
                }
                optionMenu.addAction(carAction)
                
            default:
                break
            }
        }
        
        // device actions only required if no headphone available
        if !headphonesExist {
            if (isCurrentOutput(portType: .builtInReceiver) ||
                isCurrentOutput(portType: .builtInMic)) {
                deviceAction.setValue(true, forKey: "checked")
            }
            optionMenu.addAction(deviceAction)
        }
        
        // configure speaker action
        let speakerAction = UIAlertAction(title: speakerTitle, style: .default) { _ in
            self.setOutputToSpeaker()
        }
        if isCurrentOutput(portType: .builtInSpeaker) {
            speakerAction.setValue(true, forKey: "checked")
        }
        optionMenu.addAction(speakerAction)
        
        // configure cancel action
        let cancelAction = UIAlertAction(title: cancelTitle, style: .cancel)
        optionMenu.addAction(cancelAction)
        
        optionMenu.modalPresentationStyle = .popover
        if let presenter = optionMenu.popoverPresentationController {
            presenter.sourceView = sourceView
            presenter.sourceRect = sourceView.bounds
        }
        
        presenterViewController.present(optionMenu, animated: true, completion: nil)
        
        // auto dismiss after 5 seconds
        DispatchQueue.main.asyncAfter(deadline: .now() + 5.0) {
            optionMenu.dismiss(animated: true, completion: nil)
        }
    }
    
    @objc func setOutputToSpeaker() {
        do {
            try AVAudioSession.sharedInstance().overrideOutputAudioPort(AVAudioSession.PortOverride.speaker)
        } catch let error as NSError {
            print("audioSession error turning on speaker: \(error.localizedDescription)")
        }
    }
    
    fileprivate func setPreferredInput(port: AVAudioSessionPortDescription) {
        do {
            try AVAudioSession.sharedInstance().setPreferredInput(port)
        } catch let error as NSError {
            print("audioSession error change to input: \(port.portName) with error: \(error.localizedDescription)")
        }
    }
    
    fileprivate func setToDevice(port: AVAudioSessionPortDescription) {
        do {
            // remove speaker if needed
            try AVAudioSession.sharedInstance().overrideOutputAudioPort(AVAudioSession.PortOverride.none)
            // set new input
            try AVAudioSession.sharedInstance().setPreferredInput(port)
        } catch let error as NSError {
            print("audioSession error change to input: \(AVAudioSession.PortOverride.none.rawValue) with error: \(error.localizedDescription)")
        }
    }
    
    @objc func isCurrentOutput(portType: AVAudioSession.Port) -> Bool {
        AVAudioSession.sharedInstance().currentRoute.outputs.contains(where: { $0.portType == portType })
    }
    
}

How to use

class ViewController: UIViewController {

    @IBOutlet weak var audioButton: UIButton!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBAction func selectAudio(_ sender: Any) {
        // present audio device selection action sheet
        AudioDeviceHandler.shared.presentAudioOutput(self, audioButton)
    }
    
}

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Result

Qt: Get the list of available audio devices in Linux

Apparently the only way to do this is to fire the aplay/arecord process from Qt, get the result output from the process and parse the output string to find card names and corresponding IDs. As this approach is too dependent on the output string format of those processes, I didn't use it.

Instead, I chose the PulseAudio server to fetch available devices on my system. I also used it for audio I/O as it provides much better control than Qt's multimedia API.

How to list available audio i/o devices in Bash

I guess the best you can do is typing system_profiler SPAudioDataType, then you can format the output with sed/grep/awk. It's what I do when I want to list USB devices in osx, for example.

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