The MediaSource.isTypeSupported()
static method returns a boolean value which is true
if the given MIME type is likely to be supported by the current user agent.
That is, if it can successfully create SourceBuffer
objects for that MIME type. If the returned value is false
, then the user agent is certain that it cannot access media of the specified format.
isTypeSupported(mimeType)
A boolean value which is true
if the browser feels that it can probably play media of the specified type. This is not a guarantee, however, and your code must be prepared for the possibility that the media will not play correctly if at all. A value of false
is a guarantee that media of the given type will not play, however.
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.
The following snippet is from an example written by Nick Desaulniers (view the full demo live, or download the source for further investigation.)
var assetURL = 'frag_bunny.mp4';
var mimeCodec = 'video/mp4; codecs="avc1.42E01E, mp4a.40.2"';
if ('MediaSource' in window && MediaSource.isTypeSupported(mimeCodec)) {
var mediaSource = new MediaSource;
video.src = URL.createObjectURL(mediaSource);
mediaSource.addEventListener('sourceopen', sourceOpen);
} else {
console.error('Unsupported MIME type or codec: ', mimeCodec);
}
function sourceOpen (_) {
var mediaSource = this;
var sourceBuffer = mediaSource.addSourceBuffer(mimeCodec);
fetchAB(assetURL, function (buf) {
sourceBuffer.addEventListener('updateend', function (_) {
mediaSource.endOfStream();
video.play();
});
sourceBuffer.appendBuffer(buf);
});
};