--- "@context": https://schema.org "@type": TechArticle "@id": https://www.twilio.com/docs/video/ios-v5-configuring-audio-video-inputs-and-outputs#article headline: Configuring Audio, Video Input and Output devices - iOS description: Learn how to configure Audio and Video input and output devices from your Twilio Video iOS application. url: https://www.twilio.com/docs/video/ios-v5-configuring-audio-video-inputs-and-outputs inLanguage: en dateModified: 2026-06-25T22:34:50.000Z author: "@type": Organization name: Twilio Developer Education Team publisher: "@type": Organization name: Twilio --- # Configuring Audio, Video Input and Output devices - iOS Configure audio and video input and output devices from your Twilio Video iOS application to build a better end user experience. This guide covers selecting a specific video input and selecting specific audio routes. ## Selecting a specific Video Input The `CameraSource` class captures from an `AVCaptureDevice`, and provides frames to a `LocalVideoTrack`. **Add selected video source to local track** ```swift // The default initializer will succeed if the front camera is available. if let camera = CameraSource(delegate: self), let videoTrack = LocalVideoTrack(source: camera) { // VideoView is a VideoRenderer and can be added to any VideoTrack. let renderer = VideoView(frame: view.bounds) // Add renderer to the video track videoTrack.addRenderer(renderer) self.localVideoTrack = videoTrack self.camera = camera self.view.addSubview(renderer) } else { print("Couldn't create CameraSource or LocalVideoTrack") } // Select between the front and back camera. func flipCamera() { var newDevice: AVCaptureDevice? if let camera = self.camera, let captureDevice = camera.device { if captureDevice.position == .front { newDevice = CameraSource.captureDevice(position: .back) } else { newDevice = CameraSource.captureDevice(position: .front) } if let newDevice = newDevice { camera.selectCaptureDevice(newDevice) { (captureDevice, videoFormat, error) in if let error = error { print("Error selecting capture device.\ncode = \((error as NSError).code) error = \(error.localizedDescription)") } } } } } ``` **Optionally set VideoEncodingMode in ConnectOptions** VideoEncodingMode represents the modes of behavior of the `videoEncodingMode` property in `ConnectOptions`. The `videoEncodingMode` API is mutually exclusive with existing codec management APIs `EncodingParameters.maxVideoBitrate` and `preferredVideoCodecs`. The default value is unset. `auto` - In this mode, the SDK selects the video codecs and manages encodings automatically. ```swift let connectOptions = ConnectOptions(token: accessToken) { (builder) in builder.roomName = "my-room" builder.videoEncodingMode = .auto } var room = TwilioVideoSDK.connect(options: connectOptions, delegate: self) ``` ## Selecting specific Audio routes Typically, the audio input and output route is chosen by the end user in Control Center. By default TwilioVideo will manage the application's `AVAudioSession` and configure it for video conferencing use cases. If you wish to modify audio behavior, including session configuration, you can create your own [`DefaultAudioDevice`](https://twilio.github.io/twilio-video-ios/docs/latest_5.x/Classes/TVIDefaultAudioDevice.html) and provide it as an option before connecting to a Room. ```swift // Override the device before creating any Rooms or Tracks. self.audioDevice = DefaultAudioDevice() TwilioVideoSDK.audioDevice = self.audioDevice let localAudioTrack = LocalAudioTrack() let connectOptions = ConnectOptions(token: accessToken) { (builder) in builder.roomName = "my-room" if let audioTrack = localAudioTrack { builder.audioTracks = [ audioTrack ] } } var room = TwilioVideoSDK.connect(options: connectOptions, delegate: self) ``` To configure the `AVAudioSession`, `DefaultAudioDevice` executes the `kDefaultAVAudioSessionConfigurationBlock` by default. You can alter the `AVAudioSession` configuration for your application by providing a `block` to the `DefaultAudioDevice`. For example, the input and output audio routes can be overwritten by altering the `AVAudioSession` configuration in the block that you provide to `DefaultAudioDevice`. The following example demonstrates how to configure `AVAudioSession` for voice chat scenarios. This will prefer using the device's receiver and bottom microphone like a voice call in the Phone app. ```swift // Change the audio route after connecting to a Room. self.audioDevice.block = { do { DefaultAudioDevice.DefaultAVAudioSessionConfigurationBlock() let audioSession = AVAudioSession.sharedInstance() try audioSession.setMode(.voiceChat) } catch let error as NSError { print("Fail: \(error.localizedDescription)") } } self.audioDevice.block(); ``` You must use your own `AVAudioEngineDevice` audio device that uses the `kAudioUnitSubType_RemoteIO` `componentSubType` of the `AudioComponentDescription` in order to change microphone orientations. The next Objective-C example demonstrates how to select the back microphone. This might be useful if your subject is behind the phone, and being captured with the back camera. ```objc // Change this to `AVAudioSessionOrientationFront` if you wish to use the front microphone. NSString *microphone = AVAudioSessionOrientationBack; typeof(self) __weak weakSelf = self; self.audioDevice.block = ^ { kTVIDefaultAVAudioSessionConfigurationBlock(); [weakSelf setMicrophoneInUse:microphone]; }; self.audioDevice.block(); - (void)setMicrophoneInUse:(NSString *)nextDataSource { NSError *theError = nil; BOOL result = YES; AVAudioSession *session = [AVAudioSession sharedInstance]; result = [session setActive:YES error:&theError]; // Get the set of available inputs. If there are no audio accessories attached, there will be // only one available input -- the built in microphone. NSArray *inputs = [session currentRoute].inputs; // Locate the Port corresponding to the built-in microphone. AVAudioSessionPortDescription *builtInMicPort = nil; for (AVAudioSessionPortDescription *port in inputs) { if ([port.portType isEqualToString:AVAudioSessionPortBuiltInMic]) { builtInMicPort = port; break; } } if ([builtInMicPort.preferredDataSource.orientation isEqualToString:nextDataSource]) { return; } // loop over the built-in mic's data sources and attempt to locate the specified microphone AVAudioSessionDataSourceDescription *theDataSource = nil; for (AVAudioSessionDataSourceDescription *source in builtInMicPort.dataSources) { if ([source.orientation isEqual:nextDataSource]) { theDataSource = source; break; } } // end data source iteration if (theDataSource) { theError = nil; if ([theDataSource.orientation isEqualToString:AVAudioSessionOrientationBack]) { result = [theDataSource setPreferredPolarPattern:AVAudioSessionPolarPatternSubcardioid error:&theError]; if (!result) { NSLog (@"Failed to set AVAudioSessionPolarPatternSubcardioid failed"); } } else if ([theDataSource.orientation isEqualToString:AVAudioSessionOrientationFront]) { result = [theDataSource setPreferredPolarPattern:AVAudioSessionPolarPatternCardioid error:&theError]; if (!result) { NSLog (@"Failed to set AVAudioSessionPolarPatternCardioid failed"); } } // Set a preference for the front data source. theError = nil; result = [builtInMicPort setPreferredDataSource:theDataSource error:&theError]; if (!result) { // an error occurred. Handle it! NSLog(@"setPreferredDataSource failed"); } } // Make sure the built-in mic is selected for input. This will be a no-op if the built-in mic is // already the current input Port. theError = nil; result = [session setPreferredInput:builtInMicPort error:&theError]; if (!result) { // an error occurred. Handle it! NSLog(@"setPreferredInput failed"); } } ```