MediaSource.activeSourceBuffers

The activeSourceBuffers read-only property of the MediaSource interface returns a SourceBufferList object containing a subset of the SourceBuffer objects contained within SourceBuffers — the list of objects providing the selected video track, enabled audio tracks, and shown/hidden text tracks.

Syntax

var myActiveSourceBuffers = mediaSource.activeSourceBuffers;

Value

A SourceBufferList.

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();
      console.log(mediaSource.activeSourceBuffers);
      // will contain the source buffer that was added above,
      // as it is selected for playing in the video player
      video.play();
      //console.log(mediaSource.readyState); // ended
    });
    sourceBuffer.appendBuffer(buf);
  });
};

...

Specifications

Specification	Status	Comment
Media Source Extensions The definition of 'activeSourceBuffers' 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