Web/API/MediaTrackSupportedConstraints/frameRate
The MediaTrackSupportedConstraints
dictionary's frameRate
property is a read-only Boolean value which is present (and set to true
) in the object returned by MediaDevices.getSupportedConstraints()
if and only if the user agent supports the frameRate
constraint. If the constraint isn't supported, it's not included in the list, so this value will never be false
.
The frameRate
constraint can be used to establish acceptable upper and lower bounds on the video frame rate for a new video track, or to specify an exact frame rate that must be provided for the request to succeed. Checking the value of this property lets you determine if the user agent allows constraining the video track configuration by frame rate. See the example to see how this can be used.
Syntax
frameRateConstraintSupported = supportedConstraintsDictionary.frameRate;
Value
This property is present in the dictionary if the user agent supports the frameRate
constraint. If the property isn't present, the user agent doesn't allow specifying limits on the frame rate for video tracks.
If this property is present, its value is always true
.
Example
This simple example looks to see if your browser supports constraining the frame rate when requesting video tracks.
JavaScript
let result = document.getElementById("result");
if (navigator.mediaDevices.getSupportedConstraints().frameRate) {
result.innerHTML = "Supported!";
} else {
result.innerHTML = "Not supported!";
}
HTML
<div id="result">
</div>
CSS
#result {
font: 14px "Arial", sans-serif;
}
Result
The output, showing if your browser supports the frameRate
constraint, is:
While this example is trivial, you can replace the simple output of "Supported" vs. "Not supported" with code to provide alternative methods for presenting the audiovisual information you want to share with the user or otherwise work with.
Specifications
Specification | Status | Comment |
---|---|---|
Media Capture and StreamsThe definition of 'frameRate' in that specification. | Candidate Recommendation | Initial specification. |
Browser compatibility
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.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
frameRate
|
Chrome
Full support 52 |
Edge
Full support ≤79 |
Firefox
Full support 42 |
IE
No support No |
Opera
Full support Yes |
Safari
? |
WebView Android
Full support 52 |
Chrome Android
Full support 52 |
Firefox Android
Full support 42 |
Opera Android
Full support Yes |
Safari iOS
? |
Samsung Internet Android
Full support 6.0 |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
See also
- Media Capture and Streams API
MediaDevices.getSupportedConstraints()
MediaTrackSupportedConstraints
MediaStreamTrack
MediaTrackSupportedConstraints.frameRate by Mozilla Contributors is licensed under CC-BY-SA 2.5.