MediaSource.isTypeSupported()
static method returns a
布尔
value which is
true
if the given MIME type is
likely
to be supported by the current
用户代理
.
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.
var isItSupported = mediaSource.isTypeSupported(mimeType);
mimeType
codecs
parameter to provide added details about the codecs used within the file.
A
布尔
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 ，或 download the source for further investigation.)
var assetURL = 'frag_bunny.mp4';
// Need to be specific for Blink regarding codecs
// ./mp4info frag_bunny.mp4 | grep Codec
var mimeCodec = 'video/mp4; codecs="avc1.42E01E, mp4a.40.2"';
if ('MediaSource' in window && MediaSource.isTypeSupported(mimeCodec)) {
var mediaSource = new MediaSource;
//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
var mediaSource = this;
var sourceBuffer = mediaSource.addSourceBuffer(mimeCodec);
fetchAB(assetURL, function (buf) {
sourceBuffer.addEventListener('updateend', function (_) {
mediaSource.endOfStream();
video.play();
//console.log(mediaSource.readyState); // ended
});
sourceBuffer.appendBuffer(buf);
});
};
| 规范 | 状态 | 注释 |
|---|---|---|
|
媒体源扩展
The definition of 'isTypeSupported()' in that specification. |
推荐 | 初始定义。 |
| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
isTypeSupported
|
Chrome 23 | Edge 12 |
Firefox
42
|
IE 11 | Opera 15 | Safari 8 | WebView Android 4.4.3 | Chrome Android 25 | Firefox Android 41 | Opera Android 14 | Safari iOS 不支持 No | Samsung Internet Android 1.5 |
完整支持
不支持
实验。期望将来行为有所改变。
见实现注意事项。
用户必须明确启用此特征。
SourceBuffer
SourceBufferList
MediaSource