MediaStreamConstraints - Web APIs 编辑

The MediaStreamConstraints dictionary is used when calling getUserMedia() to specify what kinds of tracks should be included in the returned MediaStream, and, optionally, to establish constraints for those tracks' settings.

To learn more about how constraints work, see Capabilities, constraints, and settings.

Properties

Some combination—but not necessarily all—of the following properties will exist on the object.

Track constraints

audio

Either a Boolean (which indicates whether or not an audio track is requested) or a MediaTrackConstraints object providing the constraints which must be met by the audio track included in the returned MediaStream. If constraints are specified, an audio track is inherently requested.

video

Either a Boolean (which indicates whether or not a video track is requested) or a MediaTrackConstraints object providing the constraints which must be met by the video track included in the returned MediaStream. If constraints are specified, a video track is inherently requested.

Security

peerIdentity

A DOMString identifying the peer who has sole access to the stream. If this property is specified, only the indicated peer can receive and use the stream. Streams isolated in this way can only be displayed in a media element (<audio> or <video>) where the content is protected just as if CORS cross-origin rules were in effect. When a peer identity is set, MediaStreamTracks from that peer have their isolated flag set to true.

Browser compatibility

BCD tables only load in the browser

See also

• MediaDevices.getUserMedia()
• MediaStreamTrack.getConstraints()
• MediaStreamTrack.applyConstraints()
• MediaDevices.getSupportedConstraints()
• MediaTrackSupportedConstraints
• MediaStreamTrack.getSettings()