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MediaSource: isTypeSupported() static method

The MediaSource.isTypeSupported() static method returns a boolean value which is true if the given MIME type and (optional) codec are likely to be supported by the current user agent.

That is, if it can successfully create SourceBuffer objects for that media type. If the returned value is false, then the user agent is certain that it cannot access media of the specified format.

Syntax

js

MediaSource.isTypeSupported(type)

Parameters

type

A string specifying the MIME type of the media and (optionally) a codecs parameter containing a comma-separated list of the supported codecs.

Return value

A value of false if the media of the given type will not play.

A value of true is returned if the browser can probably play media of the specified type. This is not a guarantee, and your code must be prepared for the possibility that the media will not play correctly if at all.

All web APIs that work with media files use a "no/maybe/probably" approach (or, in this case, "no or probably") when determining if a media type can be used. This is because media files are complex, intricate constructs with far too many subtle variations to be absolutely certain of anything until you actually use the contents of the media.

Examples

The following snippet is from 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.

js

const assetURL = "frag_bunny.mp4";
// Need to be specific for Blink regarding codecs
// ./mp4info frag_bunny.mp4 | grep Codec
const mimeCodec = 'video/mp4; codecs="avc1.42E01E, mp4a.40.2"';
let mediaSource;

if ("MediaSource" in window && MediaSource.isTypeSupported(mimeCodec)) {
  mediaSource = getMediaSource();
  console.log(mediaSource.readyState); // closed
  video.src = URL.createObjectURL(mediaSource);
  mediaSource.addEventListener("sourceopen", sourceOpen);
} else {
  console.error("Unsupported MIME type or codec: ", mimeCodec);
}

function sourceOpen() {
  console.log(this.readyState); // open
  const sourceBuffer = mediaSource.addSourceBuffer(mimeCodec);
  fetchAB(assetURL, (buf) => {
    sourceBuffer.addEventListener("updateend", () => {
      mediaSource.endOfStream();
      video.play();
      console.log(mediaSource.readyState); // ended
    });
    sourceBuffer.appendBuffer(buf);
  });
}

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
isTypeSupported_static
23["codecs string can contain any subset of optional parameters (should be all or none).", "Errors if codecs string contains unexpected characters (should evaluate string up to character)."]
12["codecs string can contain any subset of optional parameters (should be all or none).", "Errors if codecs string contains unexpected characters (should evaluate string up to character)."]
42Before Firefox 101, isTypeSupported() ignored codecs parameter options for av01 codecs (treating them as av1).
11Only works on Windows 8+.
15["codecs string can contain any subset of optional parameters (should be all or none).", "Errors if codecs string contains unexpected characters (should evaluate string up to character)."]
8
4.4.3["codecs string can contain any subset of optional parameters (should be all or none).", "Errors if codecs string contains unexpected characters (should evaluate string up to character)."]
25["codecs string can contain any subset of optional parameters (should be all or none).", "Errors if codecs string contains unexpected characters (should evaluate string up to character)."]
41Before Firefox 101, isTypeSupported() ignored codecs parameter options for av01 codecs (treating them as av1).
14["codecs string can contain any subset of optional parameters (should be all or none).", "Errors if codecs string contains unexpected characters (should evaluate string up to character)."]
13Exposed in Mobile Safari on iPad but not on iPhone.
1.5["codecs string can contain any subset of optional parameters (should be all or none).", "Errors if codecs string contains unexpected characters (should evaluate string up to character)."]

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/MediaSource/isTypeSupported_static