Skip to main content

getAudioData()

Part of the @remotion/media-utils package of helper functions.

Takes an audio src, loads it and returns data and metadata for the specified source.

info

Remote audio files need to support CORS.

More info

Arguments​

src​

A string pointing to an audio asset.

options?v4.0.121​

sampleRate?v4.0.121​

The sampleRate that should be passed into the AudioContext constructor. If not provided, the default value is 48000.

In versions before 4.0.121, the default value was undefined, leading to undeterministic behavior across devices rendering.

Return value​

Promise<AudioData>

An object with information about the audio data:

channelWaveforms​

Float32Array[]

An array with waveform information for each channel.

sampleRate​

number

The sample rate of the generated AudioContext. This will be the same as the sampleRate input option if passed, 48000 otherwise, and in version previous to 4.0.121, the sample rate of the device's preferred output device.

note

Previously, this documentation stated that this is the sample rate of the audio file. This is incorrect. The sample rate of the audio file is not exposed to the browser's JavaScript environment.

durationInSeconds​

number

The duration of the audio in seconds.

numberOfChannels​

number

The number of channels contained in the audio file. This corresponds to the length of the channelWaveforms array.

resultId​

string Unique identifier of this audio data fetching call. Other functions can cache expensive operations if they get called with the same resultId multiple times.

isRemote​

boolean

Whether the audio was imported locally or from a different origin.

Example​

ts
import {getAudioData} from '@remotion/media-utils';
import music from './music.mp3';
 
await getAudioData(music); /* {
  channelWaveforms: [Float32Array(4410000), Float32Array(4410000)],
  sampleRate: 44100,
  durationInSeconds: 100.0000,
  numberOfChannels: 2,
  resultId: "0.432878981",
  isRemote: false
} */
await getAudioData('https://example.com/remote-audio.aac'); /* {
  channelWaveforms: [Float32Array(4800000)],
  sampleRate: 48000,
  durationInSeconds: 100.0000,
  numberOfChannels: 1,
  resultId: "0.432324444",
  isRemote: true
} */
await getAudioData(staticFile('my-file.wav')); /* {
  channelWaveforms: [Float32Array(4800000)],
  sampleRate: 48000,
  durationInSeconds: 100.0000,
  numberOfChannels: 1,
  resultId: "0.6891332223",
  isRemote: false
} */
ts
import {getAudioData} from '@remotion/media-utils';
import music from './music.mp3';
 
await getAudioData(music); /* {
  channelWaveforms: [Float32Array(4410000), Float32Array(4410000)],
  sampleRate: 44100,
  durationInSeconds: 100.0000,
  numberOfChannels: 2,
  resultId: "0.432878981",
  isRemote: false
} */
await getAudioData('https://example.com/remote-audio.aac'); /* {
  channelWaveforms: [Float32Array(4800000)],
  sampleRate: 48000,
  durationInSeconds: 100.0000,
  numberOfChannels: 1,
  resultId: "0.432324444",
  isRemote: true
} */
await getAudioData(staticFile('my-file.wav')); /* {
  channelWaveforms: [Float32Array(4800000)],
  sampleRate: 48000,
  durationInSeconds: 100.0000,
  numberOfChannels: 1,
  resultId: "0.6891332223",
  isRemote: false
} */

Errors​

If you pass in a file that has no audio track, this function will throw an error you need to handle.

To determine if a file has an audio track, you may use the getVideoMetadata() function on the server to reject a file if it has no audio track. To do so, check if the audioCodec field is null.

Caching behavior​

This function is memoizing the results it returns.

If you pass in the same argument to src multiple times, it will return a cached version from the second time on, regardless of if the file has changed.
To clear the cache, you have to reload the page.

Alternatives​

If you need only the duration, prefer getAudioDurationInSeconds() which is faster because it doesn't need to read waveform data.

Use the useAudioData() helper hook to not have to do state management yourself and to wrap the call in delayRender().

See also​