我们的志愿者还没有将这篇文章翻译为 中文 (简体)。加入我们帮助完成翻译！
The MediaStream.getTrackById() method returns a MediaStreamTrack object representing the track with the specified ID string. If there is no track with the specified ID, this method returns null.
Syntax
var track = MediaStream.getTrackById(id);
Parameters
id- A
DOMStringwhich identifies the track to be returned.
Return value
If a track is found for which MediaStreamTrack.id matches the specified id string, that MediaStreamTrack object is returned. Otherwise, the returned value is null.
Example
This example activates a commentary track on a video by ducking the audio level of the main audio track to 50%, then enabling the commentary track.
stream.getTrackById("primary-audio-track").applyConstraints({ volume: 0.5 });
stream.getTrackById("commentary-track").enabled = true;
Specifications
| Specification | Status | Comment |
|---|---|---|
| Media Capture and Streams The definition of 'getTrackById()' in that specification. |
Editor's Draft | Initial specification. |
Browser compatibility
?
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | ? | 49 (49) | No support | ? | ? |
| Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | ? | ? | 49.0 (49) | No support | ? | ? |