MediaSource.readyState

这是一个实验中的功能
此功能某些浏览器尚在开发中，请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订，所以在未来版本的浏览器中该功能的语法和行为可能随之改变。

readyState是 MediaSource 接口的一个只读属性。它返回一个集合表明当前MediaSource的状态。它有三种可能的返回值：

  • closed: 当前源并未附着到一个media元素上。
  • open: 当前源已附着到一个media元素并准备好接收 SourceBuffer 对象。
  • ended: 当前源已附着到一个media元素，但流已被MediaSource.endOfStream()结束。

语法

var myReadyState = mediaSource.readyState;

值

A DOMString.

例子

The following snippet is from a simple example written by Nick Desaulniers (view the full demo live, or download the source for further investigation.)

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

Specification Status Comment
Media Source Extensions
readyState		 Recommendation Initial definition.

浏览器兼容性表格

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!
Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 23 (Yes) 25.0 (25.0)[1]
42.0 (42.0)		 11[2] 15 8
Feature Android Edge Firefox Mobile (Gecko) Firefox OS (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support 4.4.4 (Yes)

未实现

 未实现 11 30 未实现

[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

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