VideoTrack
interface represents a single video track from a
<video>
元素。
The most common use for accessing a
VideoTrack
object is to toggle its
selected
property in order to make it the active video track for its
<video>
元素。
selected
true
for one track while another track is active will make that other track inactive.
id
只读
DOMString
which uniquely identifies the track within the media. This ID can be used to locate a specific track within a video track list by calling
VideoTrackList.getTrackById()
. The ID can also be used as the fragment part of the URL if the media supports seeking by media fragment per the
Media Fragments URI specification
.
kind
只读
DOMString
specifying the category into which the track falls. For example, the main video track would have a
kind
of
"main"
.
label
只读
DOMString
providing a human-readable label for the track. For example, a track whose
kind
is
"sign"
might have a
label
of
"A sign-language interpretation"
. This string is empty if no label is provided.
语言
只读
DOMString
specifying the video track's primary language, or an empty string if unknown. The language is specified as a BCP 47 (
RFC 5646
) language code, such as
"en-US"
or
"pt-BR"
.
sourceBuffer
只读
SourceBuffer
that created the track. Returns null if the track was not created by a
SourceBuffer
或
SourceBuffer
has been removed from the
MediaSource.sourceBuffers
attribute of its parent media source.
To get a
VideoTrack
for a given media element, use the element's
videoTracks
property, which returns a
VideoTrackList
object from which you can get the individual tracks contained in the media:
var el = document.querySelector("video");
var tracks = el.videoTracks;
You can then access the media's individual tracks using either array syntax or functions such as
forEach()
.
This first example gets the first video track on the media:
var firstTrack = tracks[0];
The next example scans through all of the media's video tracks, activating the first video track that is in the user's preferred language (taken from a variable
userLanguage
).
for (var i = 0; i < tracks.length; i++) {
if (tracks[i].language === userLanguage) {
tracks[i].selected = true;
break;
}
});
语言
is in standard (
RFC 5646
) format. For US English, this would be
"en-US"
,例如。
| 规范 | 状态 | 注释 |
|---|---|---|
|
HTML 实时标准
The definition of 'VideoTrack' in that specification. |
实时标准 |
| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
VideoTrack
|
Chrome
45
Disabled
|
Edge
79
Disabled
|
Firefox 33 | IE 10 |
Opera
32
Disabled
|
Safari 6.1 | WebView Android 45 |
Chrome Android
45
Disabled
|
Firefox Android 33 |
Opera Android
32
Disabled
|
Safari iOS 7 | Samsung Internet Android No |
id
|
Chrome
45
Disabled
|
Edge
79
Disabled
|
Firefox 33 | IE 10 |
Opera
32
Disabled
|
Safari 6.1 | WebView Android 45 |
Chrome Android
45
Disabled
|
Firefox Android 33 |
Opera Android
32
Disabled
|
Safari iOS 7 | Samsung Internet Android No |
kind
|
Chrome
45
Disabled
|
Edge
79
Disabled
|
Firefox 33 | IE 10 |
Opera
32
Disabled
|
Safari 6.1 | WebView Android 45 |
Chrome Android
45
Disabled
|
Firefox Android 33 |
Opera Android
32
Disabled
|
Safari iOS 7 | Samsung Internet Android No |
label
|
Chrome
45
Disabled
|
Edge
79
Disabled
|
Firefox 33 | IE 10 |
Opera
32
Disabled
|
Safari 6.1 | WebView Android 45 |
Chrome Android
45
Disabled
|
Firefox Android 33 |
Opera Android
32
Disabled
|
Safari iOS 7 | Samsung Internet Android No |
语言
|
Chrome
45
Disabled
|
Edge
79
Disabled
|
Firefox 33 | IE 10 |
Opera
32
Disabled
|
Safari 6.1 | WebView Android 45 |
Chrome Android
45
Disabled
|
Firefox Android 33 |
Opera Android
32
Disabled
|
Safari iOS 7 | Samsung Internet Android No |
selected
|
Chrome
45
Disabled
|
Edge
79
Disabled
|
Firefox 33 | IE 10 |
Opera
32
Disabled
|
Safari 6.1 | WebView Android 45 |
Chrome Android
45
Disabled
|
Firefox Android 33 |
Opera Android
32
Disabled
|
Safari iOS 7 | Samsung Internet Android No |
sourceBuffer
|
Chrome
45
Disabled
|
Edge
79
Disabled
|
Firefox No | IE 10 |
Opera
32
Disabled
|
Safari 6.1 | WebView Android 45 |
Chrome Android
45
Disabled
|
Firefox Android No |
Opera Android
32
Disabled
|
Safari iOS 7 | Samsung Internet Android No |
完整支持
不支持
用户必须明确启用此特征。
VideoTrack
BeforeUnloadEvent
DOMStringMap
ErrorEvent
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HashChangeEvent
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