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Expo Audio iconExpo Audio

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A library that provides an API to implement audio playback and recording in apps.


Audio from 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

Installation

Terminal
npx expo install expo-av

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

Usage

Playing sounds

Playing sounds
import { useEffect, useState } from 'react';
import { View, StyleSheet, Button } from 'react-native';
import { Audio } from 'expo-av';

export default function App() {
  const [sound, setSound] = 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();
  }

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

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

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

Recording sounds

Recording sounds
import { useState } from 'react';
import { View, StyleSheet, Button } from 'react-native';
import { Audio } from 'expo-av';

export default function App() {
  const [recording, setRecording] = useState();
  const [permissionResponse, requestPermission] = Audio.usePermissions();

  async function startRecording() {
    try {
      if (permissionResponse.status !== 'granted') {
        console.log('Requesting permission..');
        await requestPermission();
      }
      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();
    await Audio.setAudioModeAsync(
      {
        allowsRecordingIOS: false,
      }
    );
    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>
  );
}

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

Playing or recording audio in background 
iOS

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 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"
        ]
      }
    }
  }
}

Notes on web usage

  • 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, utilizing 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 for them to listen to a mic. See MediaDevices getUserMedia() security for more details.

API

import { Audio } from 'expo-av';

Constants

Audio.RecordingOptionsPresets

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,
  },
};

Hooks

usePermissions(options)

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 [permissionResponse, requestPermission] = Audio.usePermissions();

Returns

  • [null | PermissionResponse, RequestPermissionMethod<PermissionResponse>, GetPermissionMethod<PermissionResponse>]

Classes

Recording

Warning: Experimental for web.

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!
}

Returns

A newly constructed instance of Audio.Recording.

Recording Methods

createAsync(options, onRecordingStatusUpdate, progressUpdateIntervalMillis)

NameTypeDescription
options
(optional)
RecordingOptions

Options 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) => void

A function taking a single parameter status (a dictionary, described in getStatusAsync).

Default: null
progressUpdateIntervalMillis
(optional)
null | number

The 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!
}

Returns

  • Promise<RecordingObject>

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

Deprecated. Use createNewLoadedSoundAsync() instead.

createNewLoadedSound(initialStatus, onPlaybackStatusUpdate)

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

Returns


createNewLoadedSoundAsync(initialStatus, onPlaybackStatusUpdate)

NameTypeDescription
initialStatus
(optional)
AVPlaybackStatusToSet

The 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) => void

A 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.

Returns


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

getAvailableInputs()

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

Returns


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

getCurrentInput()

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

Returns


A Promise that is fulfilled with a RecordingInput object.

getStatusAsync()

Gets the status of the Recording.

Returns


A Promise that is resolved with the RecordingStatus object.

getURI()

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.

Returns

  • null | 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).

pauseAsync()

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

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

Returns


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.

prepareToRecordAsync(options)

NameTypeDescription
options
(optional)
RecordingOptions

RecordingOptions 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.

Returns


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.

setInput(inputUid)

NameTypeDescription
inputUidstring

The uid of a RecordingInput.


Sets the current recording input.

Returns


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

setOnRecordingStatusUpdate(onRecordingStatusUpdate)

NameTypeDescription
onRecordingStatusUpdatenull | (status: RecordingStatus) => void

A 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.

Returns

  • void

setProgressUpdateInterval(progressUpdateIntervalMillis)

NameTypeDescription
progressUpdateIntervalMillisnumber

The 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.

Returns

  • void

startAsync()

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

Returns


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.

stopAndUnloadAsync()

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.

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.

Returns


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.

Sound

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!
}

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.

Returns

A newly constructed instance of Audio.Sound.

Sound Methods

Deprecated. Use Sound.createAsync() instead

create(source, initialStatus, onPlaybackStatusUpdate, downloadFirst)

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

Returns

  • Promise<SoundObject>

createAsync(source, initialStatus, onPlaybackStatusUpdate, downloadFirst)

NameTypeDescription
sourceAVPlaybackSource

The source of the sound. See the AV documentation for details on the possible source values.

initialStatus
(optional)
AVPlaybackStatusToSet

The 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) => void

A 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)
boolean

If 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!
}

Returns


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

setOnAudioSampleReceived(callback)

NameTypeDescription
callbackAudioSampleCallback

A function taking the AudioSampleCallback as parameter.


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

Returns

  • void

Only for:
iOS

setOnMetadataUpdate(onMetadataUpdate)

NameTypeDescription
onMetadataUpdate(metadata: AVMetadata) => void

A 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.

Returns

  • void

setOnPlaybackStatusUpdate(onPlaybackStatusUpdate)

NameTypeDescription
onPlaybackStatusUpdatenull | (status: AVPlaybackStatus) => void

A function taking a single parameter AVPlaybackStatus.


Sets a function to be called regularly with the AVPlaybackStatus of the playback object.

onPlaybackStatusUpdate will be called whenever a call to the API for this playback object completes (such as setStatusAsync(), getStatusAsync(), or unloadAsync()), nd will also be called at regular intervals while the media is in the loaded state.

Set progressUpdateIntervalMillis via setStatusAsync() or setProgressUpdateIntervalAsync() to modify the interval with which onPlaybackStatusUpdate is called while loaded.

Returns

  • void

Methods

Audio.getPermissionsAsync()

Checks user's permissions for audio recording.

Returns

  • Promise<PermissionResponse>

A promise that resolves to an object of type PermissionResponse.

Audio.requestPermissionsAsync()

Asks the user to grant permissions for audio recording.

Returns

  • Promise<PermissionResponse>

A promise that resolves to an object of type PermissionResponse.

Audio.setAudioModeAsync(partialMode)

NameTypeDescription
partialModePartial<AudioMode>-

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

Returns

  • Promise<void>

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

Audio.setIsEnabledAsync(value)

NameTypeDescription
valueboolean

true 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.

Returns

  • Promise<void>

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

Interfaces

PermissionResponse

An object obtained by permissions get and request functions.

PermissionResponse Properties

NameTypeDescription
canAskAgainboolean

Indicates 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.

expiresPermissionExpiration

Determines time when the permission expires.

grantedboolean

A convenience boolean that indicates if the permission is granted.

statusPermissionStatus

Determines the status of the permission.


Types

AudioChannel

NameTypeDescription
framesnumber[]

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

AudioMode

NameTypeDescription
allowsRecordingIOS
(optional)
boolean

A boolean selecting if recording is enabled on iOS.

When this flag is set to true, playback may be routed to the phone earpiece instead of to the speaker. Set it back to false after stopping recording to reenable playback through the speaker.

Default: false
interruptionModeAndroidInterruptionModeAndroid

An enum selecting how your experience's audio should interact with the audio from other apps on Android.

interruptionModeIOSInterruptionModeIOS

An enum selecting how your experience's audio should interact with the audio from other apps on iOS.

playThroughEarpieceAndroid
(optional)
boolean

A boolean selecting if the audio is routed to earpiece on Android.

Default: false
playsInSilentModeIOS
(optional)
boolean

A boolean selecting if your experience's audio should play in silent mode on iOS.

Default: false
shouldDuckAndroid
(optional)
boolean

A 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)
boolean

A boolean selecting if the audio session (playback or recording) should stay active even when the app goes into background.

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

AudioSample

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).

timestampnumber

A number representing the timestamp of the current sample in seconds, relative to the audio track's timeline.

Known issue: When using the ExoPlayer Android implementation, the timestamp is always -1.

PermissionHookOptions

Literal Type: multiple types

Acceptable values are: PermissionHookBehavior | Options

RecordingInput

NameTypeDescription
namestring-
typestring-
uidstring-

RecordingObject

NameTypeDescription
recordingRecording

The newly created and started Recording object.

statusRecordingStatus

The RecordingStatus of the Recording object. See the AV documentation for further information.

RecordingOptions

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
androidRecordingOptionsAndroid

Recording options for the Android platform.

iosRecordingOptionsIOS

Recording options for the iOS platform.

isMeteringEnabled
(optional)
boolean

A boolean that determines whether audio level information will be part of the status object under the "metering" key.

keepAudioActiveHint
(optional)
boolean

A 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().

webRecordingOptionsWeb

Recording options for the Web platform.

RecordingOptionsAndroid

NameTypeDescription
audioEncoderAndroidAudioEncoder | number

The desired audio encoder. See the AndroidAudioEncoder enum for all valid values.

bitRate
(optional)
number

The 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
extensionstring

The desired file extension. Example valid values are .3gp and .m4a. For more information, see the Android docs for supported output formats.

maxFileSize
(optional)
number

The desired maximum file size in bytes, after which the recording will stop (but stopAndUnloadAsync() must still be called after this point).

Example
numberOfChannels
(optional)
number

The 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
outputFormatAndroidOutputFormat | number

The desired file format. See the AndroidOutputFormat enum for all valid values.

sampleRate
(optional)
number

The 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

RecordingOptionsIOS

NameTypeDescription
audioQualityIOSAudioQuality | number

The desired audio quality. See the IOSAudioQuality enum for all valid values.

bitDepthHint
(optional)
number

The desired bit depth hint.

Example
bitRatenumber

The desired bit rate.

Example
bitRateStrategy
(optional)
number

The desired bit rate strategy. See the next section for an enumeration of all valid values of bitRateStrategy.

extensionstring

The desired file extension.

Example
linearPCMBitDepth
(optional)
number

The desired PCM bit depth.

Example
linearPCMIsBigEndian
(optional)
boolean

A boolean describing if the PCM data should be formatted in big endian.

linearPCMIsFloat
(optional)
boolean

A boolean describing if the PCM data should be encoded in floating point or integral values.

numberOfChannelsnumber

The desired number of channels.

Example
outputFormat
(optional)
string | IOSOutputFormat | number

The desired file format. See the IOSOutputFormat enum for all valid values.

sampleRatenumber

The desired sample rate.

Example

RecordingOptionsWeb

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

RecordingStatus

NameTypeDescription
canRecordboolean

A boolean describing if the Recording can initiate the recording.

durationMillisnumber

The current duration of the recorded audio or the final duration is the recording has been stopped.

isDoneRecordingboolean

A boolean describing if the Recording has been stopped.

isRecordingboolean

A boolean describing if the Recording is currently recording.

mediaServicesDidReset
(optional)
booleanOnly for:
iOS

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)
number

A 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-

SoundObject

NameTypeDescription
soundSound

The newly created and loaded Sound object.

statusAVPlaybackStatus

The PlaybackStatus of the Sound object. See the AV documentation for further information.

Enums

AndroidAudioEncoder

AndroidAudioEncoder Values

DEFAULT

AndroidAudioEncoder.DEFAULT = 0

AMR_NB

AndroidAudioEncoder.AMR_NB = 1

AMR_WB

AndroidAudioEncoder.AMR_WB = 2

AAC

AndroidAudioEncoder.AAC = 3

HE_AAC

AndroidAudioEncoder.HE_AAC = 4

AAC_ELD

AndroidAudioEncoder.AAC_ELD = 5

AndroidOutputFormat

AndroidOutputFormat Values

DEFAULT

AndroidOutputFormat.DEFAULT = 0

THREE_GPP

AndroidOutputFormat.THREE_GPP = 1

MPEG_4

AndroidOutputFormat.MPEG_4 = 2

AMR_NB

AndroidOutputFormat.AMR_NB = 3

AMR_WB

AndroidOutputFormat.AMR_WB = 4

AAC_ADIF

AndroidOutputFormat.AAC_ADIF = 5

AAC_ADTS

AndroidOutputFormat.AAC_ADTS = 6

RTP_AVP

AndroidOutputFormat.RTP_AVP = 7

MPEG2TS

AndroidOutputFormat.MPEG2TS = 8

WEBM

AndroidOutputFormat.WEBM = 9

InterruptionModeAndroid

InterruptionModeAndroid Values

DoNotMix

InterruptionModeAndroid.DoNotMix = 1

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

DuckOthers

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

InterruptionModeIOS Values

MixWithOthers

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.

DoNotMix

InterruptionModeIOS.DoNotMix = 1

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

DuckOthers

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

IOSAudioQuality Values

MIN

IOSAudioQuality.MIN = 0

LOW

IOSAudioQuality.LOW = 32

MEDIUM

IOSAudioQuality.MEDIUM = 64

HIGH

IOSAudioQuality.HIGH = 96

MAX

IOSAudioQuality.MAX = 127

IOSBitRateStrategy

IOSBitRateStrategy Values

CONSTANT

IOSBitRateStrategy.CONSTANT = 0

LONG_TERM_AVERAGE

IOSBitRateStrategy.LONG_TERM_AVERAGE = 1

VARIABLE_CONSTRAINED

IOSBitRateStrategy.VARIABLE_CONSTRAINED = 2

VARIABLE

IOSBitRateStrategy.VARIABLE = 3

IOSOutputFormat

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 Values

MPEGLAYER1

IOSOutputFormat.MPEGLAYER1 = ".mp1"

MPEGLAYER2

IOSOutputFormat.MPEGLAYER2 = ".mp2"

MPEGLAYER3

IOSOutputFormat.MPEGLAYER3 = ".mp3"

MPEG4AAC

IOSOutputFormat.MPEG4AAC = "aac "

MPEG4AAC_ELD

IOSOutputFormat.MPEG4AAC_ELD = "aace"

MPEG4AAC_ELD_SBR

IOSOutputFormat.MPEG4AAC_ELD_SBR = "aacf"

MPEG4AAC_ELD_V2

IOSOutputFormat.MPEG4AAC_ELD_V2 = "aacg"

MPEG4AAC_HE

IOSOutputFormat.MPEG4AAC_HE = "aach"

MPEG4AAC_LD

IOSOutputFormat.MPEG4AAC_LD = "aacl"

MPEG4AAC_HE_V2

IOSOutputFormat.MPEG4AAC_HE_V2 = "aacp"

MPEG4AAC_SPATIAL

IOSOutputFormat.MPEG4AAC_SPATIAL = "aacs"

AC3

IOSOutputFormat.AC3 = "ac-3"

AES3

IOSOutputFormat.AES3 = "aes3"

APPLELOSSLESS

IOSOutputFormat.APPLELOSSLESS = "alac"

ALAW

IOSOutputFormat.ALAW = "alaw"

AUDIBLE

IOSOutputFormat.AUDIBLE = "AUDB"

60958AC3

IOSOutputFormat.60958AC3 = "cac3"

MPEG4CELP

IOSOutputFormat.MPEG4CELP = "celp"

ENHANCEDAC3

IOSOutputFormat.ENHANCEDAC3 = "ec-3"

MPEG4HVXC

IOSOutputFormat.MPEG4HVXC = "hvxc"

ILBC

IOSOutputFormat.ILBC = "ilbc"

APPLEIMA4

IOSOutputFormat.APPLEIMA4 = "ima4"

LINEARPCM

IOSOutputFormat.LINEARPCM = "lpcm"

MACE3

IOSOutputFormat.MACE3 = "MAC3"

MACE6

IOSOutputFormat.MACE6 = "MAC6"

AMR

IOSOutputFormat.AMR = "samr"

AMR_WB

IOSOutputFormat.AMR_WB = "sawb"

DVIINTELIMA

IOSOutputFormat.DVIINTELIMA = 1836253201

MICROSOFTGSM

IOSOutputFormat.MICROSOFTGSM = 1836253233

QUALCOMM

IOSOutputFormat.QUALCOMM = "Qclp"

QDESIGN2

IOSOutputFormat.QDESIGN2 = "QDM2"

QDESIGN

IOSOutputFormat.QDESIGN = "QDMC"

MPEG4TWINVQ

IOSOutputFormat.MPEG4TWINVQ = "twvq"

ULAW

IOSOutputFormat.ULAW = "ulaw"

PermissionStatus

PermissionStatus Values

DENIED

PermissionStatus.DENIED = "denied"

User has denied the permission.

GRANTED

PermissionStatus.GRANTED = "granted"

User has granted the permission.

UNDETERMINED

PermissionStatus.UNDETERMINED = "undetermined"

User hasn't granted or denied the permission yet.

PitchCorrectionQuality

Check official Apple documentation for more information.

PitchCorrectionQuality Values

High

PitchCorrectionQuality.High = number

Equivalent to AVAudioTimePitchAlgorithmSpectral.

Low

PitchCorrectionQuality.Low = number

Equivalent to AVAudioTimePitchAlgorithmLowQualityZeroLatency.

Medium

PitchCorrectionQuality.Medium = number

Equivalent to AVAudioTimePitchAlgorithmTimeDomain.

Unified API

The rest of the API on the Sound.Audio is the same as the API for Video component ref. See the AV documentation for more information.