MediaCapabilities.encodingInfo()

The MediaCapabilities.encodingInfo() method, part of the MediaCapabilities interface of the Media Capabilities API, returns a promise with the tested media configuration's capabilities information; this contains the three Boolean properties supported, smooth, and powerefficient, which describe how compatible the device is with the type of media.

Syntax

mediaCapabilities.encodingInfo(mediaEncodingConfiguration)

Parameters

mediaEncodingConfiguration

A valid MediaEncodingConfiguration dictionary containing a valid media encoding type of record or transmission and a valid media configuration: either an AudioConfiguration or VideoConfiguration dictionary.

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 encodingInfo() method is invalid, either because the type is not video or audio, the contentType is not a valid codec MIME type, or any other error in the media configuration passed to the method, including omitting any of the media encoding configuration elements.

Example

//Create media configuration to be tested
const mediaConfig = {
    type : 'record', // or 'transmission'
    video : {
        contentType : "video/webm;codecs=vp8.0", // valid content type
        width : 1920,     // width of the video
        height : 1080,    // height of the video
        bitrate : 120000, // number of bits used to encode 1s of video
        framerate : 48   // number of frames making up that 1s.
     }
};

// check support and performance
navigator.mediaCapabilities.encodingInfo(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

• MediaEncodingConfiguration
• VideoConfiguration
• AudioConfiguration
• MediaCapabilities.decodingInfo()