This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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


mediaSource.duration = 5.5; // 5.5 seconds

var myDuration = mediaSource.duration;


A double. A value in seconds is expected.


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

Exception 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.)


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.duration = 120;;
      //console.log(mediaSource.readyState); // ended



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

Browser compatibility

BCD tables only load in the browser

See also