The AudioConfiguration dictionary of the Media Capabilities API defines the audio file being tested when calling MediaCapabilities.encodingInfo() or MediaCapabilities.decodingInfo() to query whether a specific audio configuration is supported, smooth, and/or power efficient.


The AudioConfiguration dictionary is made up of four audio properties, including:

  • contentType: A valid audio MIME type, For information on possible values and what they mean, see the web audio codec guide.
  • channels: the number of channels used by the audio track.
  • bitrate: The number of bits used to encode one second of the audio file.
  •  samplerate: The number of audio samples making up one second of the audio file.


//Create media configuration to be tested
const mediaConfig = {
    type : 'file', // 'record', 'transmission', or 'media-source'
    audio : {
        contentType : "audio/ogg", // valid content type
        channels : 2,     // audio channels used by the track
        bitrate : 132700, // number of bits used to encode 1s of audio
        samplerate : 5200 // number of audio samples making up that 1s.

// check support and performance
navigator.mediaCapabilities.decodingInfo(mediaConfig).then(result => {
    console.log('This configuration is ' +
        (result.supported ? '' : 'not ') + 'supported, ' +
        (result.smooth ? '' : 'not ') + 'smooth, and ' +
        (result.powerEfficient ? '' : 'not ') + 'power efficient.'


Specification Status Comment
Media Capabilities
The definition of 'AudioConfiguration' in that specification.
Draft Initial definition

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See also