MediaSource.duration

The duration property of the MediaSource interface gets and sets the duration of the current media being presented.

Syntax

mediaSource.duration = 5.5; // 5.5 seconds

var myDuration = mediaSource.duration;

Value

A double. A value in seconds is expected.

Errors

The following errors may be thrown when setting a new value for this property.

Error	Explanation
InvalidAccessError	An attempt was made to set a duration value that was negative, or NaN.
InvalidStateError	MediaSource.readyState is not equal to open, or one or more of the SourceBuffer objects in MediaSource.sourceBuffers are being updated (i.e. their SourceBuffer.updating property is true.)

Example

The following snippet is based on a simple example written by Nick Desaulniers (view the full demo live, or download the source for further investigation.)

function sourceOpen (_) {
  //console.log(this.readyState); // open
  var mediaSource = this;
  var sourceBuffer = mediaSource.addSourceBuffer(mimeCodec);
  fetchAB(assetURL, function (buf) {
    sourceBuffer.addEventListener('updateend', function (_) {
      mediaSource.endOfStream();
      mediaSource.duration = 120;
      video.play();
      //console.log(mediaSource.readyState); // ended
    });
    sourceBuffer.appendBuffer(buf);
  });
};

...

Specifications

Specification	Status	Comment
Media Source Extensions The definition of 'duration' in that specification.	Candidate Recommendation	Initial definition.

Browser compatibility

[1] Available after switching the about:config preference media.mediasource.enabled to true. In addition, support was limited to a whitelist of sites, for example YouTube, Netflix, and other popular streaming sites. The whitelist was removed and Media Source Extensions was enabled by default in 42+ for all sites.

[2] Only works on Windows 8+.

See also

• SourceBuffer
• SourceBufferList