The read-only voiceActivityFlag property of the RTCRtpSynchronizationSource interface indicates whether or not the most recent RTP packet on the source includes voice activity. This is only present if the stream is using the voice activity detection feature; see the RTCOfferOptions flag voiceActivityDetection.


var voiceActivity = RTCRtpSynchronizationSource.voiceActivityFlag


A Boolean value which is true if voice activity is present in the most recently received RTP packet played by the associated source, or false if voice activity is not present.

This property is omitted entirely if voice activity detection is not enabled on the source, or if the RFC 6464 extension header isn't present.


Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'voiceActivityFlag' in that specification.
Candidate Recommendation Initial definition.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support No ?591 No No ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support No No ?591 No ? No

1. From version 59: this feature is behind the media.peerconnection.rtpsourcesapi.enable preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Document Tags and Contributors

Contributors to this page: fscholz, Sheppy
Last updated by: fscholz,