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Expo Audio

GitHub

npm

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

Android

iOS

tvOS

Web

Audio from expo-av allows you to implement audio playback and recording in your app.

Audio recording APIs are not available on tvOS (Apple TV).

Note that audio automatically stops if headphones/bluetooth audio devices are disconnected.

See the playlist example app for an example on the media playback API, and the recording example app for an example of the recording API.

Installation

Terminal

- npx expo install expo-av

If you are installing this in an existing React Native app, start by installing expo in your project. Then, follow the additional instructions as mentioned by the library's README under "Installation in bare React Native projects" section.

Usage

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

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)`

Parameter	Type
options (optional)	`PermissionHookOptions<object>`

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

Returns:

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

Example

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

Classes

Only for:

Android

iOS

`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.

Returns

A newly constructed instance of Audio.Recording.

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!
}

Recording Methods

`createAsync(options, onRecordingStatusUpdate, progressUpdateIntervalMillis)`

Parameter	Type	Description
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();

Returns:

Promise<RecordingObject>

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

Example

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

Deprecated Use createNewLoadedSoundAsync() instead.

`createNewLoadedSound(initialStatus, onPlaybackStatusUpdate)`

Parameter	Type
initialStatus (optional)	`AVPlaybackStatusToSet`
onPlaybackStatusUpdate (optional)	`null \| (status: AVPlaybackStatus) => void`

Returns:

Promise<SoundObject>

`createNewLoadedSoundAsync(initialStatus, onPlaybackStatusUpdate)`

Parameter	Type	Description
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:

Promise<SoundObject>

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:

Promise<RecordingInput[]>

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:

Promise<RecordingInput>

A Promise that is fulfilled with a RecordingInput object.

`getStatusAsync()`

Gets the status of the Recording.

Returns:

Promise<RecordingStatus>

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:

Promise<RecordingStatus>

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)`

Parameter	Type	Description
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:

Promise<RecordingStatus>

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)`

Parameter	Type	Description
inputUid	`string`	The uid of a `RecordingInput`.

Sets the current recording input.

Returns:

Promise<void>

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

`setOnRecordingStatusUpdate(onRecordingStatusUpdate)`

Parameter	Type	Description
onRecordingStatusUpdate	`null \| (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)`

Parameter	Type	Description
progressUpdateIntervalMillis	`number`	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:

Promise<RecordingStatus>

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:

Promise<RecordingStatus>

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.

Returns

A newly constructed instance of Audio.Sound.

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.

Sound Methods

Deprecated Use Sound.createAsync() instead

`create(source, initialStatus, onPlaybackStatusUpdate, downloadFirst)`

Parameter	Type
source	`AVPlaybackSource`
initialStatus (optional)	`AVPlaybackStatusToSet`
onPlaybackStatusUpdate (optional)	`null \| (status: AVPlaybackStatus) => void`
downloadFirst (optional)	`boolean`

Returns:

Promise<SoundObject>

`createAsync(source, initialStatus, onPlaybackStatusUpdate, downloadFirst)`

Parameter	Type	Description
source	`AVPlaybackSource`	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 `source`s 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);

Returns:

Promise<SoundObject>

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

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!
}

`setOnAudioSampleReceived(callback)`

Parameter	Type	Description
callback	`AudioSampleCallback`	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)`

Parameter	Type	Description
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)`

Parameter	Type	Description
onPlaybackStatusUpdate	`null \| (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

Only for:

Android

iOS

`Audio.getPermissionsAsync()`

Checks user's permissions for audio recording.

Returns:

Promise<PermissionResponse>

A promise that resolves to an object of type PermissionResponse.

Only for:

Android

iOS

`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)`

Parameter	Type
partialMode	`Partial<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)`

Parameter	Type	Description
value	`boolean`	`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

Name	Type	Description
canAskAgain	`boolean`	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.
expires	`PermissionExpiration`	Determines time when the permission expires.
granted	`boolean`	A convenience boolean that indicates if the permission is granted.
status	`PermissionStatus`	Determines the status of the permission.

Types

`AudioChannel`

Name	Type	Description
frames	`number[]`	All samples for this specific Audio Channel in PCM Buffer format (-1 to 1).

`AudioMode`

Name	Type	Description
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`
interruptionModeAndroid	`InterruptionModeAndroid`	An enum selecting how your experience's audio should interact with the audio from other apps on Android.
interruptionModeIOS	`InterruptionModeIOS`	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.

Name Type Description

Name	Type	Description
channels	`AudioChannel[]`	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).
timestamp	`number`	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`.

channels

AudioChannel[]

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).

timestamp

number

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

Only for:

Android

iOS

`RecordingInput`

Name	Type	Description
name	`string`	-
type	`string`	-
uid	`string`	-

Only for:

Android

iOS

`RecordingObject`

Name	Type	Description
recording	`Recording`	The newly created and started `Recording` object.
status	`RecordingStatus`	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).

Name	Type	Description
android	`RecordingOptionsAndroid`	Recording options for the Android platform.
ios	`RecordingOptionsIOS`	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()`.
web	`RecordingOptionsWeb`	Recording options for the Web platform.

Only for:

Android

`RecordingOptionsAndroid`

Name	Type	Description
audioEncoder	`AndroidAudioEncoder \| 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 `128000`
extension	`string`	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 `65536`
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 `1`, `2`
outputFormat	`AndroidOutputFormat \| 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 44100

Only for:

iOS

`RecordingOptionsIOS`

Name	Type	Description
audioQuality	`IOSAudioQuality \| number`	The desired audio quality. See the `IOSAudioQuality` enum for all valid values.
bitDepthHint (optional)	`number`	The desired bit depth hint. Example `16`
bitRate	`number`	The desired bit rate. Example `128000`
bitRateStrategy (optional)	`number`	The desired bit rate strategy. See the next section for an enumeration of all valid values of `bitRateStrategy`.
extension	`string`	The desired file extension. Example `'.caf'`
linearPCMBitDepth (optional)	`number`	The desired PCM bit depth. Example `16`
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.
numberOfChannels	`number`	The desired number of channels. Example `1`, `2`
outputFormat (optional)	`string \| IOSOutputFormat \| number`	The desired file format. See the `IOSOutputFormat` enum for all valid values.
sampleRate	`number`	The desired sample rate. Example `44100`

`RecordingOptionsWeb`

Name	Type	Description
bitsPerSecond (optional)	`number`	-
mimeType (optional)	`string`	-

`RecordingStatus`

Name	Type	Description
canRecord	`boolean`	Only for: Android iOS A boolean describing if the `Recording` can initiate the recording.
durationMillis	`number`	Only for: Android iOS The current duration of the recorded audio or the final duration is the recording has been stopped.
isDoneRecording	`boolean`	Only for: Android iOS A boolean describing if the `Recording` has been stopped.
isRecording	`boolean`	Only for: Android iOS A boolean describing if the `Recording` is currently recording.
mediaServicesDidReset (optional)	`boolean`	Only 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`	Only for: Android iOS 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`

Name	Type	Description
sound	`Sound`	The newly created and loaded `Sound` object.
status	`AVPlaybackStatus`	The `PlaybackStatus` of the `Sound` object. See the AV documentation for further information.

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