MediaTrackConstraints
The MediaTrackConstraints
dictionary is used to describe a set of capabilities and the value or values each can take on. A constraints dictionary is passed into applyConstraints()
to allow a script to establish a set of ideal values and/or preferred ranges of values for the track, and the most recently-requested set of custom constraints can be retrieved by calling getConstraints()
.
To learn more about how constraints work, see "Capabilities and constraints" in Media Capture and Streams API (Media Streams).
Properties
Some combination—but not necessarily all—of the following properties will exist on the object.
width
- A Boolean value whose value is
true
if thewidth
constraint is supported in the current environment. height
- A Boolean value whose value is
true
if theheight
constraint is supported in the current environment. aspectRatio
- A Boolean value whose value is
true
if theaspectRatio
constraint is supported in the current environment. frameRate
- A Boolean value whose value is
true
if theframeRate
constraint is supported in the current environment. facingMode
- A Boolean value whose value is
true
if thefacingMode
constraint is supported in the current environment. volume
- A Boolean value whose value is
true
if thevolume
constraint is supported in the current environment. sampleRate
- A Boolean value whose value is
true
if thesampleRate
constraint is supported in the current environment. sampleSize
- A Boolean value whose value is
true
if thesampleSize
constraint is supported in the current environment. echoCancellation
- A Boolean value whose value is
true
if theechoCancellation
constraint is supported in the current environment. latency
- A Boolean value whose value is
true
if thelatency
constraint is supported in the current environment. channelCount
- A Boolean value whose value is
true
if thechannelCount
constraint is supported in the current environment. deviceId
- A Boolean value whose value is
true
if thedeviceId
constraint is supported in the current environment. groupId
- A Boolean value whose value is
true
if thegroupId
constraint is supported in the current environment.
See also
MediaDevices.getUserMedia()
MediaStreamTrack.getConstraints()
MediaStreamTrack.applyConstraints()
MediaStreamTrack.getSettings()
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/mediatrackconstraints