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Audio

expo-av allows you to implement audio playback and recording in your app.
Note that audio automatically stops if headphones / bluetooth audio devices are disconnected.
Try the playlist example app (source code is on GitHub) to see an example usage of the media playback API, and the recording example app (source code is on GitHub) to see an example usage of the recording API.

Platform Compatibility

Android DeviceAndroid EmulatoriOS DeviceiOS SimulatorWeb
Status-success-iconStatus-success-iconStatus-success-iconStatus-success-iconStatus-success-icon

Installation

Terminal
→ expo install expo-av

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

import * as React from 'react';
import { Text, View, StyleSheet, Button } from 'react-native';
import { Audio } from 'expo-av';

export default function App() {
  const [sound, setSound] = React.useState();

  async function playSound() {
    console.log('Loading Sound');
    const { sound } = await Audio.Sound.createAsync(
       require('./assets/Hello.mp3')
    );
    setSound(sound);

    console.log('Playing Sound');
    await sound.playAsync(); }

  React.useEffect(() => {
    return sound
      ? () => {
          console.log('Unloading Sound');
          sound.unloadAsync(); }
      : undefined;
  }, [sound]);

  return (
    <View style={styles.container}>
      <Button title="Play Sound" onPress={playSound} />
    </View>
  );
}

%%placeholder-start%%const styles = StyleSheet.create({ ... }); %%placeholder-end%%const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    backgroundColor: '#ecf0f1',
    padding: 10,
  },
});

import * as React from 'react';
import { Text, View, StyleSheet, Button } from 'react-native';
import { Audio } from 'expo-av';

export default function App() {
  const [recording, setRecording] = React.useState();

  async function startRecording() {
    try {
      console.log('Requesting permissions..');
      await Audio.requestPermissionsAsync();
      await Audio.setAudioModeAsync({
        allowsRecordingIOS: true,
        playsInSilentModeIOS: true,
      }); 
      console.log('Starting recording..');
      const { recording } = await Audio.Recording.createAsync(
         Audio.RecordingOptionsPresets.HIGH_QUALITY
      );
      setRecording(recording);
      console.log('Recording started');
    } catch (err) {
      console.error('Failed to start recording', err);
    }
  }

  async function stopRecording() {
    console.log('Stopping recording..');
    setRecording(undefined);
    await recording.stopAndUnloadAsync();
    const uri = recording.getURI(); 
    console.log('Recording stopped and stored at', uri);
  }

  return (
    <View style={styles.container}>
      <Button
        title={recording ? 'Stop Recording' : 'Start Recording'}
        onPress={recording ? stopRecording : startRecording}
      />
    </View>
  );
}

%%placeholder-start%%const styles = StyleSheet.create({ ... }); %%placeholder-end%%const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    backgroundColor: '#ecf0f1',
    padding: 10,
  },
});

On iOS, audio playback and recording in background is only available in standalone apps, and it requires some extra configuration. On iOS, each background feature requires a special key in UIBackgroundModes array in your Info.plist file. In standalone apps this array is empty by default, so in order to use background features you will need to add appropriate keys to your app.json configuration.
See an example of app.json that enables audio playback in background:
{
  "expo": {
    ...
    "ios": {
      ...
      "infoPlist": {
        ...
        "UIBackgroundModes": [
          "audio"
        ]
      }
    }
  }
}

  • A MediaRecorder issue on Chrome produces WebM files missing the duration metadata. See the open Chromium issue
  • MediaRecorder encoding options and other configurations are inconsistent across browsers, utilising a Polyfill such as kbumsik/opus-media-recorder or ai/audio-recorder-polyfill in your application will improve your experience. Any options passed to prepareToRecordAsync will be passed directly to the MediaRecorder API and as such the polyfill.
  • Web browsers require sites to be served securely in order for them to listen to a mic. See MediaDevices#getUserMedia Security for more details.

import { Audio } from 'expo-av';

Type: Record<string, RecordingOptions>

Constant which contains definitions of the two preset examples of RecordingOptions, as implemented in the Audio SDK.

HIGH_QUALITY

RecordingOptionsPresets.HIGH_QUALITY = {
  isMeteringEnabled: true,
  android: {
    extension: '.m4a',
    outputFormat: AndroidOutputFormat.MPEG_4,
    audioEncoder: AndroidAudioEncoder.AAC,
    sampleRate: 44100,
    numberOfChannels: 2,
    bitRate: 128000,
  },
  ios: {
    extension: '.m4a',
    outputFormat: IOSOutputFormat.MPEG4AAC,
    audioQuality: IOSAudioQuality.MAX,
    sampleRate: 44100,
    numberOfChannels: 2,
    bitRate: 128000,
    linearPCMBitDepth: 16,
    linearPCMIsBigEndian: false,
    linearPCMIsFloat: false,
  },
  web: {
    mimeType: 'audio/webm',
    bitsPerSecond: 128000,
  },
};

LOW_QUALITY

RecordingOptionsPresets.LOW_QUALITY = {
  isMeteringEnabled: true,
  android: {
    extension: '.3gp',
    outputFormat: AndroidOutputFormat.THREE_GPP,
    audioEncoder: AndroidAudioEncoder.AMR_NB,
    sampleRate: 44100,
    numberOfChannels: 2,
    bitRate: 128000,
  },
  ios: {
    extension: '.caf',
    audioQuality: IOSAudioQuality.MIN,
    sampleRate: 44100,
    numberOfChannels: 2,
    bitRate: 128000,
    linearPCMBitDepth: 16,
    linearPCMIsBigEndian: false,
    linearPCMIsFloat: false,
  },
  web: {
    mimeType: 'audio/webm',
    bitsPerSecond: 128000,
  },
};

NameTypeDescription
options
(optional)
PermissionHookOptions<object>-

Check or request permissions to record audio. This uses both requestPermissionAsync and getPermissionsAsync to interact with the permissions.

Example

const [status, requestPermission] = Audio.usePermissions();
  • Undo-icon[null | PermissionResponse, RequestPermissionMethod<PermissionResponse>, GetPermissionMethod<PermissionResponse>]

This class represents an audio recording. After creating an instance of this class, prepareToRecordAsync must be called in order to record audio. Once recording is finished, call stopAndUnloadAsync. Note that only one recorder is allowed to exist in the state between prepareToRecordAsync and stopAndUnloadAsync at any given time.

Note that your experience must request audio recording permissions in order for recording to function. See the Permissions module for more details.

Additionally, audio recording is not supported in the iOS Simulator.

Example

const recording = new Audio.Recording();
try {
  await recording.prepareToRecordAsync(Audio.RecordingOptionsPresets.HIGH_QUALITY);
  await recording.startAsync();
  // You are now recording!
} catch (error) {
  // An error occurred!
}

A newly constructed instance of Audio.Recording.

NameTypeDescription
options
(optional)
RecordingOptionsOptions for the recording, including sample rate, bitrate, channels, format, encoder, and extension. If no options are passed to, the recorder will be created with options Audio.RecordingOptionsPresets.LOW_QUALITY. See below for details on RecordingOptions.
Default: RecordingOptionsPresets.LOW_QUALITY
onRecordingStatusUpdate
(optional)
null | (status: RecordingStatus) => voidA function taking a single parameter status (a dictionary, described in getStatusAsync).
Default: null
progressUpdateIntervalMillis
(optional)
null | numberThe interval between calls of onRecordingStatusUpdate. This value defaults to 500 milliseconds.
Default: null

Creates and starts a recording using the given options, with optional onRecordingStatusUpdate and progressUpdateIntervalMillis.

const { recording, status } = await Audio.Recording.createAsync(
  options,
  onRecordingStatusUpdate,
  progressUpdateIntervalMillis
);

// Which is equivalent to the following:
const recording = new Audio.Recording();
await recording.prepareToRecordAsync(options);
recording.setOnRecordingStatusUpdate(onRecordingStatusUpdate);
await recording.startAsync();

Example

try {
  const { recording: recordingObject, status } = await Audio.Recording.createAsync(
    Audio.RecordingOptionsPresets.HIGH_QUALITY
  );
  // You are now recording!
} catch (error) {
  // An error occurred!
}

A Promise that is rejected if creation failed, or fulfilled with the following dictionary if creation succeeded.

Warning-icon
Deprecated. Use createNewLoadedSoundAsync() instead.

NameTypeDescription
initialStatus
(optional)
AVPlaybackStatusToSet-
onPlaybackStatusUpdate
(optional)
null | (status: AVPlaybackStatus) => void-

NameTypeDescription
initialStatus
(optional)
AVPlaybackStatusToSetThe initial intended PlaybackStatusToSet of the sound, whose values will override the default initial playback status. This value defaults to {} if no parameter is passed. See the AV documentation for details on PlaybackStatusToSet and the default initial playback status.
Default: {}
onPlaybackStatusUpdate
(optional)
null | (status: AVPlaybackStatus) => voidA function taking a single parameter PlaybackStatus. This value defaults to null if no parameter is passed. See the AV documentation for details on the functionality provided by onPlaybackStatusUpdate
Default: null

Creates and loads a new Sound object to play back the Recording. Note that this will only succeed once the Recording is done recording and stopAndUnloadAsync() has been called.

A Promise that is rejected if creation failed, or fulfilled with the SoundObject.

Returns a list of available recording inputs. This method can only be called if the Recording has been prepared.

A Promise that is fulfilled with an array of RecordingInput objects.

Returns the currently-selected recording input. This method can only be called if the Recording has been prepared.

A Promise that is fulfilled with a RecordingInput object.

Gets the status of the Recording.

A Promise that is resolved with the RecordingStatus object.

Gets the local URI of the Recording. Note that this will only succeed once the Recording is prepared to record. On web, this will not return the URI until the recording is finished.

  • Undo-iconnull | string

A string with the local URI of the Recording, or null if the Recording is not prepared to record (or, on Web, if the recording has not finished).

Pauses recording. This method can only be called if the Recording has been prepared.

Info-icon
This is only available on Android API version 24 and later.

A Promise that is fulfilled when recording has paused, or rejects if recording could not be paused. If the Android API version is less than 24, the Promise will reject. The promise is resolved with the RecordingStatus of the recording.

NameTypeDescription
options
(optional)
RecordingOptionsRecordingOptions for the recording, including sample rate, bitrate, channels, format, encoder, and extension. If no options are passed to prepareToRecordAsync(), the recorder will be created with options Audio.RecordingOptionsPresets.LOW_QUALITY.
Default: RecordingOptionsPresets.LOW_QUALITY

Loads the recorder into memory and prepares it for recording. This must be called before calling startAsync(). This method can only be called if the Recording instance has never yet been prepared.

A Promise that is fulfilled when the recorder is loaded and prepared, or rejects if this failed. If another Recording exists in your experience that is currently prepared to record, the Promise will reject. If the RecordingOptions provided are invalid, the Promise will also reject. The promise is resolved with the RecordingStatus of the recording.

NameTypeDescription
inputUidstringThe uid of a RecordingInput.

Sets the current recording input.

A Promise that is resolved if successful or rejected if not.

NameTypeDescription
onRecordingStatusUpdatenull | (status: RecordingStatus) => voidA function taking a single parameter RecordingStatus.

Sets a function to be called regularly with the RecordingStatus of the Recording.

onRecordingStatusUpdate will be called when another call to the API for this recording completes (such as prepareToRecordAsync(), startAsync(), getStatusAsync(), or stopAndUnloadAsync()), and will also be called at regular intervals while the recording can record. Call setProgressUpdateInterval() to modify the interval with which onRecordingStatusUpdate is called while the recording can record.

  • Undo-iconvoid

NameTypeDescription
progressUpdateIntervalMillisnumberThe new interval between calls of onRecordingStatusUpdate.

Sets the interval with which onRecordingStatusUpdate is called while the recording can record. See setOnRecordingStatusUpdate for details. This value defaults to 500 milliseconds.

  • Undo-iconvoid

Begins recording. This method can only be called if the Recording has been prepared.

A Promise that is fulfilled when recording has begun, or rejects if recording could not be started. The promise is resolved with the RecordingStatus of the recording.

Stops the recording and deallocates the recorder from memory. This reverts the Recording instance to an unprepared state, and another Recording instance must be created in order to record again. This method can only be called if the Recording has been prepared.

Info-icon
On Android this method may fail with E_AUDIO_NODATA when called too soon after startAsync and no audio data has been recorded yet. In that case the recorded file will be invalid and should be discarded.

A Promise that is fulfilled when recording has stopped, or rejects if recording could not be stopped. The promise is resolved with the RecordingStatus of the recording.

Type: Class implements Playback

This class represents a sound corresponding to an Asset or URL.

Example

const sound = new Audio.Sound();
try {
  await sound.loadAsync(require('./assets/sounds/hello.mp3'));
  await sound.playAsync();
  // Your sound is playing!

  // Don't forget to unload the sound from memory
  // when you are done using the Sound object
  await sound.unloadAsync();
} catch (error) {
  // An error occurred!
}
Info-icon
Method not described below and the rest of the API for Audio.Sound is the same as the imperative playback API for Video. See the AV documentation for further information.

A newly constructed instance of Audio.Sound.

Warning-icon
Deprecated. Use Sound.createAsync() instead

NameTypeDescription
sourceAVPlaybackSource-
initialStatus
(optional)
AVPlaybackStatusToSet-
onPlaybackStatusUpdate
(optional)
null | (status: AVPlaybackStatus) => void-
downloadFirst
(optional)
boolean-

NameTypeDescription
sourceAVPlaybackSourceThe source of the sound. See the AV documentation for details on the possible source values.
initialStatus
(optional)
AVPlaybackStatusToSetThe initial intended PlaybackStatusToSet of the sound, whose values will override the default initial playback status. This value defaults to {} if no parameter is passed. See the AV documentation for details on PlaybackStatusToSet and the default initial playback status.
Default: {}
onPlaybackStatusUpdate
(optional)
null | (status: AVPlaybackStatus) => voidA function taking a single parameter PlaybackStatus. This value defaults to null if no parameter is passed. See the AV documentation for details on the functionality provided by onPlaybackStatusUpdate
Default: null
downloadFirst
(optional)
booleanIf set to true, the system will attempt to download the resource to the device before loading. This value defaults to true. Note that at the moment, this will only work for sources of the form require('path/to/file') or Asset objects.
Default: true

Creates and loads a sound from source.

const { sound } = await Audio.Sound.createAsync(
  source,
  initialStatus,
  onPlaybackStatusUpdate,
  downloadFirst
);

// Which is equivalent to the following:
const sound = new Audio.Sound();
sound.setOnPlaybackStatusUpdate(onPlaybackStatusUpdate);
await sound.loadAsync(source, initialStatus, downloadFirst);

Example

try {
  const { sound: soundObject, status } = await Audio.Sound.createAsync(
    require('./assets/sounds/hello.mp3'),
    { shouldPlay: true }
  );
  // Your sound is playing!
} catch (error) {
  // An error occurred!
}

A Promise that is rejected if creation failed, or fulfilled with the SoundObject if creation succeeded.

NameTypeDescription
callbackAudioSampleCallbackA function taking the AudioSampleCallback as parameter.

Sets a function to be called during playback, receiving the audio sample as parameter.

  • Undo-iconvoid
Only for:
Apple-iconiOS

NameTypeDescription
onMetadataUpdate(metadata: AVMetadata) => voidA function taking a single object of type AVMetadata as a parameter.

Sets a function to be called whenever the metadata of the sound object changes, if one is set.

  • Undo-iconvoid

NameTypeDescription
onPlaybackStatusUpdatenull | (status: AVPlaybackStatus) => void-
  • Undo-iconvoid

Checks user's permissions for audio recording.

A promise that resolves to an object of type PermissionResponse.

Asks the user to grant permissions for audio recording.

A promise that resolves to an object of type PermissionResponse.

NameTypeDescription
partialModePartial<AudioMode>-

We provide this API to customize the audio experience on iOS and Android.

A Promise that will reject if the audio mode could not be enabled for the device.

NameTypeDescription
valuebooleantrue enables Audio, and false disables it.

Audio is enabled by default, but if you want to write your own Audio API in a bare workflow app, you might want to disable the Audio API.

A Promise that will reject if audio playback could not be enabled for the device.

An object obtained by getPermissionsAsync and requestPermissionsAsync functions.

NameTypeDescription
canAskAgainbooleanIndicates if user can be asked again for specific permission. If not, one should be directed to the Settings app in order to enable/disable the permission.
expiresPermissionExpirationDetermines time when the permission expires.
grantedbooleanA convenience boolean that indicates if the permission is granted.
statusPermissionStatusDetermines the status of the permission.

NameTypeDescription
framesnumber[]All samples for this specific Audio Channel in PCM Buffer format (-1 to 1).

NameTypeDescription
allowsRecordingIOS
(optional)
booleanA boolean selecting if recording is enabled on iOS.
Info-icon
When this flag is set to true, playback may be routed to the phone receiver instead of to the speaker.
Default: false
interruptionModeAndroidInterruptionModeAndroidAn enum selecting how your experience's audio should interact with the audio from other apps on Android.
interruptionModeIOSInterruptionModeIOSAn enum selecting how your experience's audio should interact with the audio from other apps on iOS.
playThroughEarpieceAndroid
(optional)
booleanA boolean selecting if the audio is routed to earpiece on Android.
Default: false
playsInSilentModeIOS
(optional)
booleanA boolean selecting if your experience's audio should play in silent mode on iOS.
Default: false
shouldDuckAndroid
(optional)
booleanA boolean selecting if your experience's audio should automatically be lowered in volume ("duck") if audio from another app interrupts your experience. If false, audio from other apps will pause your audio.
Default: true
staysActiveInBackground
(optional)
booleanA boolean selecting if the audio session (playback or recording) should stay active even when the app goes into background.
Info-icon
This is not available in Expo Go for iOS, it will only work in standalone apps. To enable it for standalone apps, follow the instructions below to add UIBackgroundModes to your app configuration.
Default: false

Object passed to the onAudioSampleReceived function. Represents a single sample from an audio source. The sample contains all frames (PCM Buffer values) for each channel of the audio, so if the audio is stereo (interleaved), there will be two channels, one for left and one for right audio.

NameTypeDescription
channelsAudioChannel[]An array representing the data from each channel in PCM Buffer format. Array elements are objects in the following format: { frames: number[] }, where each frame is a number in PCM Buffer format (-1 to 1 range).
timestampnumberA number representing the timestamp of the current sample in seconds, relative to the audio track's timeline.
Info-icon
Known issue: When using the ExoPlayer Android implementation, the timestamp is always -1.

Acceptable values are: PermissionHookBehavior, Options.

NameTypeDescription
namestring-
typestring-
uidstring-

NameTypeDescription
recordingRecordingThe newly created and started Recording object.
statusRecordingStatusThe RecordingStatus of the Recording object. See the AV documentation for further information.

The recording extension, sample rate, bitrate, channels, format, encoder, etc. which can be customized by passing options to prepareToRecordAsync().

We provide the following preset options for convenience, as used in the example above. See below for the definitions of these presets.

  • Audio.RecordingOptionsPresets.HIGH_QUALITY
  • Audio.RecordingOptionsPresets.LOW_QUALITY

We also provide the ability to define your own custom recording options, but we recommend you use the presets, as not all combinations of options will allow you to successfully prepareToRecordAsync(). You will have to test your custom options on iOS and Android to make sure it's working. In the future, we will enumerate all possible valid combinations, but at this time, our goal is to make the basic use-case easy (with presets) and the advanced use-case possible (by exposing all the functionality available on all supported platforms).

NameTypeDescription
androidRecordingOptionsAndroidRecording options for the Android platform.
iosRecordingOptionsIOSRecording options for the iOS platform.
isMeteringEnabled
(optional)
booleanA boolean that determines whether audio level information will be part of the status object under the "metering" key.
keepAudioActiveHint
(optional)
booleanA boolean that hints to keep the audio active after prepareToRecordAsync completes. Setting this value can improve the speed at which the recording starts. Only set this value to true when you call startAsync immediately after prepareToRecordAsync. This value is automatically set when using Audio.recording.createAsync().
webRecordingOptionsWebRecording options for the Web platform.

NameTypeDescription
audioEncoderAndroidAudioEncoder | numberThe desired audio encoder. See the AndroidAudioEncoder enum for all valid values.
bitRate
(optional)
numberThe desired bit rate.Note that prepareToRecordAsync() may perform additional checks on the parameter to make sure whether the specified bit rate is applicable, and sometimes the passed bitRate will be clipped internally to ensure the audio recording can proceed smoothly based on the capabilities of the platform.
Example
128000
extensionstringThe desired file extension. Example valid values are .3gp and .m4a. For more information, see the Android docs for supported output formats.
maxFileSize
(optional)
numberThe desired maximum file size in bytes, after which the recording will stop (but stopAndUnloadAsync() must still be called after this point).
Example
65536
numberOfChannels
(optional)
numberThe desired number of channels.Note that prepareToRecordAsync() may perform additional checks on the parameter to make sure whether the specified number of audio channels are applicable.
Example
1, 2
outputFormatAndroidOutputFormat | numberThe desired file format. See the AndroidOutputFormat enum for all valid values.
sampleRate
(optional)
numberThe desired sample rate.Note that the sampling rate depends on the format for the audio recording, as well as the capabilities of the platform. For instance, the sampling rate supported by AAC audio coding standard ranges from 8 to 96 kHz, the sampling rate supported by AMRNB is 8kHz, and the sampling rate supported by AMRWB is 16kHz. Please consult with the related audio coding standard for the supported audio sampling rate.
Example
44100

NameTypeDescription
audioQualityIOSAudioQuality | numberThe desired audio quality. See the IOSAudioQuality enum for all valid values.
bitDepthHint
(optional)
numberThe desired bit depth hint.
Example
16
bitRatenumberThe desired bit rate.
Example
128000
bitRateStrategy
(optional)
numberThe desired bit rate strategy. See the next section for an enumeration of all valid values of bitRateStrategy.
extensionstringThe desired file extension.
Example
'.caf'
linearPCMBitDepth
(optional)
numberThe desired PCM bit depth.
Example
16
linearPCMIsBigEndian
(optional)
booleanA boolean describing if the PCM data should be formatted in big endian.
linearPCMIsFloat
(optional)
booleanA boolean describing if the PCM data should be encoded in floating point or integral values.
numberOfChannelsnumberThe desired number of channels.
Example
1, 2
outputFormat
(optional)
string | IOSOutputFormat | numberThe desired file format. See the IOSOutputFormat enum for all valid values.
sampleRatenumberThe desired sample rate.
Example
44100

NameTypeDescription
bitsPerSecond
(optional)
number-
mimeType
(optional)
string-

NameTypeDescription
canRecordbooleanA boolean describing if the Recording can initiate the recording.
durationMillisnumberThe current duration of the recorded audio or the final duration is the recording has been stopped.
isDoneRecordingbooleanA boolean describing if the Recording has been stopped.
isRecordingbooleanA boolean describing if the Recording is currently recording.
mediaServicesDidReset
(optional)
booleanOnly for:
Apple-iconiOS

A boolean indicating whether media services were reset during recording. This may occur if the active input ceases to be available during recording.For example: airpods are the active input and they run out of batteries during recording.
metering
(optional)
numberA number that's the most recent reading of the loudness in dB. The value ranges from –160 dBFS, indicating minimum power, to 0 dBFS, indicating maximum power. Present or not based on Recording options. See RecordingOptions for more information.
uri
(optional)
string | null-

NameTypeDescription
soundSoundThe newly created and loaded Sound object.
statusAVPlaybackStatusThe PlaybackStatus of the Sound object. See the AV documentation for further information.

AndroidAudioEncoder.DEFAULT = 0
AndroidAudioEncoder.AMR_NB = 1
AndroidAudioEncoder.AMR_WB = 2
AndroidAudioEncoder.AAC = 3
AndroidAudioEncoder.HE_AAC = 4
AndroidAudioEncoder.AAC_ELD = 5

AndroidOutputFormat.DEFAULT = 0
AndroidOutputFormat.THREE_GPP = 1
AndroidOutputFormat.MPEG_4 = 2
AndroidOutputFormat.AMR_NB = 3
AndroidOutputFormat.AMR_WB = 4
AndroidOutputFormat.AAC_ADIF = 5
AndroidOutputFormat.AAC_ADTS = 6
AndroidOutputFormat.RTP_AVP = 7
AndroidOutputFormat.MPEG2TS = 8
AndroidOutputFormat.WEBM = 9

InterruptionModeAndroid.DoNotMix = 1

If this option is set, your experience's audio interrupts audio from other apps.

InterruptionModeAndroid.DuckOthers = 2

This is the default option. If this option is set, your experience's audio lowers the volume ("ducks") of audio from other apps while your audio plays.

InterruptionModeIOS.MixWithOthers = 0

This is the default option. If this option is set, your experience's audio is mixed with audio playing in background apps.

InterruptionModeIOS.DoNotMix = 1

If this option is set, your experience's audio interrupts audio from other apps.

InterruptionModeIOS.DuckOthers = 2

If this option is set, your experience's audio lowers the volume ("ducks") of audio from other apps while your audio plays.

IOSAudioQuality.MIN = 0
IOSAudioQuality.LOW = 32
IOSAudioQuality.MEDIUM = 64
IOSAudioQuality.HIGH = 96
IOSAudioQuality.MAX = 127

IOSBitRateStrategy.CONSTANT = 0
IOSBitRateStrategy.LONG_TERM_AVERAGE = 1
IOSBitRateStrategy.VARIABLE_CONSTRAINED = 2
IOSBitRateStrategy.VARIABLE = 3

Info-icon
Note Not all of the iOS formats included in this list of constants are currently supported by iOS, in spite of appearing in the Apple source code. For an accurate list of formats supported by iOS, see Core Audio Codecs and iPhone Audio File Formats.
IOSOutputFormat.60958AC3 = "cac3"
IOSOutputFormat.AC3 = "ac-3"
IOSOutputFormat.AES3 = "aes3"
IOSOutputFormat.ALAW = "alaw"
IOSOutputFormat.AMR = "samr"
IOSOutputFormat.AMR_WB = "sawb"
IOSOutputFormat.APPLEIMA4 = "ima4"
IOSOutputFormat.APPLELOSSLESS = "alac"
IOSOutputFormat.AUDIBLE = "AUDB"
IOSOutputFormat.DVIINTELIMA = 1836253201
IOSOutputFormat.ENHANCEDAC3 = "ec-3"
IOSOutputFormat.ILBC = "ilbc"
IOSOutputFormat.LINEARPCM = "lpcm"
IOSOutputFormat.MACE3 = "MAC3"
IOSOutputFormat.MACE6 = "MAC6"
IOSOutputFormat.MICROSOFTGSM = 1836253233
IOSOutputFormat.MPEG4AAC = "aac "
IOSOutputFormat.MPEG4AAC_ELD = "aace"
IOSOutputFormat.MPEG4AAC_ELD_SBR = "aacf"
IOSOutputFormat.MPEG4AAC_ELD_V2 = "aacg"
IOSOutputFormat.MPEG4AAC_HE = "aach"
IOSOutputFormat.MPEG4AAC_HE_V2 = "aacp"
IOSOutputFormat.MPEG4AAC_LD = "aacl"
IOSOutputFormat.MPEG4AAC_SPATIAL = "aacs"
IOSOutputFormat.MPEG4CELP = "celp"
IOSOutputFormat.MPEG4HVXC = "hvxc"
IOSOutputFormat.MPEG4TWINVQ = "twvq"
IOSOutputFormat.MPEGLAYER1 = ".mp1"
IOSOutputFormat.MPEGLAYER2 = ".mp2"
IOSOutputFormat.MPEGLAYER3 = ".mp3"
IOSOutputFormat.QDESIGN = "QDMC"
IOSOutputFormat.QDESIGN2 = "QDM2"
IOSOutputFormat.QUALCOMM = "Qclp"
IOSOutputFormat.ULAW = "ulaw"

PermissionStatus.DENIED = "denied"

User has denied the permission.

PermissionStatus.GRANTED = "granted"

User has granted the permission.

PermissionStatus.UNDETERMINED = "undetermined"

User hasn't granted or denied the permission yet.

PitchCorrectionQuality.High
PitchCorrectionQuality.Low
PitchCorrectionQuality.Medium

The rest of the API on the Sound.Audio is the same as the API for Video component ref - see the AV documentation for further information.