MediaTrackSettings.latency - Web APIs 编辑

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.

Syntax

var latency = MediaTrackSettings.latency;

Value

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

Example

See Example: Constraint exerciser in Capabilities, constraints, and settings for an example.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

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