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• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

MediaTrackSettings dictionary's deviceId 特性为 DOMString which uniquely identifies the source for the corresponding MediaStreamTrack for the origin corresponding to the browsing session. This lets you determine what value was selected to comply with your specified constraints for this property's value as described in the MediaTrackConstraints.deviceId property you provided when calling either getUserMedia() .

If needed, you can determine whether or not this constraint is supported by checking the value of MediaTrackSupportedConstraints.deviceId as returned by a call to MediaDevices.getSupportedConstraints() . However, typically this is unnecessary since browsers will simply ignore any constraints they're unfamiliar with.

因为 RTP doesn't include this information, tracks associated with a WebRTC RTCPeerConnection will never include this property.

句法

var deviceId = MediaTrackSettings.deviceId;
					

值

A DOMString whose value is an origin-unique identifier for the track's source. This ID is valid across multiple browsing sessions for the same origin and is guaranteed to be different for all other origins, so you can safely use it to request the same source be used for multiple sessions, for example.

The actual value of the string, however, is determined by the source of the track, and there is no guarantee what form it will take, although the specification does recommend it be a GUID.

Since there is a one-to-one pairing of ID with each source, all tracks with the same source will share the same ID for any given origin, so MediaStreamTrack.getCapabilities() will always return exactly one value for deviceId . That makes the device ID not useful for any changes to constraints when calling MediaStreamTrack.applyConstraints() .

An exception to the rule that device IDs are the same across browsing sessions: private browsing mode will use a different ID, and will change it each browsing session.

范例

见 Example: Constraint exerciser in Capabilities, constraints, and settings 范例。

规范

规范	状态	注释
媒体捕获和流 The definition of 'deviceId' in that specification.	候选推荐	最初的规范。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
deviceId	Chrome Yes	Edge ≤79	Firefox 69	IE ?	Opera Yes	Safari ?	WebView Android Yes	Chrome Android Yes	Firefox Android No	Opera Android Yes	Safari iOS ?	Samsung Internet Android Yes

图例

完整支持

完整支持

不支持

不支持

兼容性未知 ?

兼容性未知

另请参阅

• Media Capture and Streams API
• Capabilities, constraints, and settings
• MediaTrackSettings.groupId
• MediaTrackConstraints.deviceId
• MediaTrackSettings

元数据

• 最后修改： 2020 年 1 月 22 日

相关话题

1. Media Streams API
2. MediaTrackSettings
3. 特性

   1. aspectRatio
   2. autoGainControl
   3. channelCount
   4. cursor
   5. deviceId
   6. displaySurface
   7. echoCancellation
   8. facingMode
   9. frameRate
   10. groupId
   11. height
   12. latency
   13. noiseSuppression
   14. sampleRate
   15. sampleSize
   16. volume
   17. width
4. Related pages for Media Capture and Streams

   1. AudioStreamTrack
   2. BlobEvent
   3. CanvasCaptureMediaStream
   4. ConstrainBoolean
   5. ConstrainDOMString
   6. ConstrainDouble
   7. ConstrainLong
   8. DoubleRange
   9. HTMLCanvasElement.captureStream()
   10. LongRange
   11. MediaDevices
   12. MediaStream
   13. MediaStreamTrack
   14. MediaStreamTrackEvent
   15. MediaTrackCapabilities
   16. MediaTrackConstraints
   17. MediaTrackSupportedConstraints
   18. Navigator.mediaDevices
   19. NavigatorUserMedia
   20. NavigatorUserMediaError
   21. VideoStreamTrack
   22. navigator.mediaDevices.getUserMedia()