MediaTrackSettings: latency property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2017.

The MediaTrackSettings dictionary's latency property is a double-precision floating-point number indicating the estimated latency (specified in seconds) of the MediaStreamTrack as currently configured. This lets you determine what value was selected to comply with your specified constraints for this property's value as described in the MediaTrackConstraints.latency property you provided when calling either getUserMedia() or MediaStreamTrack.applyConstraints().

This is, of course, an approximation, since latency can vary for many reasons including CPU, transmission, and storage overhead.

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

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

Value

A double-precision floating-point number indicating the estimated latency, in seconds, of the audio track as currently configured.

Examples

See the Constraint exerciser example.

Specifications

Specification
Media Capture and Streams
# dom-mediatrackconstraintset-latency

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
latency constraint

Legend

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Full support
Full support

See also