MediaCapabilities.decodingInfo()

The MediaCapabilities.decodingInfo() method, part of the Media Capabilities API, returns a promise with the tested media configuration's capabilities info; this contains the three Boolean properties supported, smooth, and powerefficient, which describe whether decoding the media described would be supported, smooth, and powerefficient.

Syntax

mediaCapabilities.decodingInfo(MediaDecodingConfiguration)

Parameters

MediaDecodingConfiguration

A valid MediaDecodingConfiguration dictionary containing a valid media decoding type of file or media-source and a valid media configuration: either an AudioConfiguration or a VideoConfiguration.

Return value

A Promise fulfilling with an object containing three Boolean attributes:

• supported: Given the properties defined in the MediaConfiguration, can the specified piece of media content be encoded (if MediaEncodingConfiguration is set) or decode (if MediaDecodingConfiguration is set) at all? If yes, supported is true. Otherwise, it is false.
• smooth: Given the properties defined in the MediaConfiguration, will the playback of the specified piece of media be high quality? Will it be smooth? If supported is true, and playback will be smooth, smooth is true, Otherwise, is it false.
• powerEfficient: Given the properties defined in the MediaConfiguration, will the playback of the specified piece of media be power efficient? If supported is true, and playback will be power efficient, powerEfficient is true, Otherwise, is it false.

Browsers will report a supported media configuration as smooth and powerEfficient until stats on this device have been recorded. All supported audio codecs are reported to be power efficient.

Exceptions

A TypeError is raised if the MediaConfiguration passed to the decodingInfo() method is invalid, either because the type is not video or audio, the contentType is not a valid codec MIME type, the media decoding configuration is not a valid value for the media decoding type, or any other error in the media configuration passed to the method, including omitting values required in the media decoding configuration.

Example

//Create media configuration to be tested
const mediaConfig = {
    type : 'file', // or 'media-source'
    audio : {
        contentType : "audio/ogg; codecs=vorbis", // 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.')
});

Specifications

Browser compatibility

See also

• MediaDecodingConfiguration
• VideoConfiguration
• AudioConfiguration
• MediaCapabilities.encodingInfo()