MediaSource: activeSourceBuffers property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Note: This feature is available in Dedicated Web Workers.

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.

Value

A SourceBufferList containing the SourceBuffer objects for each of the active tracks.

Examples

The following snippet is based on an example written by Nick Desaulniers (view the full demo live, or download the source for further investigation). The function getMediaSource(), which is not defined here, returns a MediaSource.

const mediaSource = getMediaSource();
function sourceOpen() {
 console.log(mediaSource.readyState); // open
 const sourceBuffer = mediaSource.addSourceBuffer(mimeCodec);
 fetchAB(assetURL, (buf) => {
 sourceBuffer.addEventListener("updateend", () => {
 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);
 });
}
// ...