The read-only sdpMLineIndex property on the RTCIceCandidate interface is a zero-based index of the m-line describing the media associated with the candidate.

This value is specified when creating the RTCIceCandidate by setting the corresponding sdpMLineIndex value in the RTCIceCandidateInit object when creating a new candidate with new RTCIceCandidate().

If you instead call RTCIceCandidate() with a string parameter containing the candidate m-line text, the value of sdpMLineIndex is extracted from the m-line.


var sdpMLineIndex = RTCIceCandidate.sdpMLineIndex;


A number containing a 0-based index into the set of m-lines providing media descriptions, indicating which media source is associated with the candidate, or null if no such association is available.

Note: Attempting to add a candidate (using addIceCandidate()) that has a value of null for either sdpMid or sdpMLineIndex will throw a TypeError exception.




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

Browser compatibility

ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
sdpMLineIndexChrome Full support 23Edge Full support 15Firefox Full support 22IE No support NoOpera Full support 15Safari Full support YesWebView Android Full support YesChrome Android Full support 25Firefox Android Full support YesOpera Android Full support 14Safari iOS Full support YesSamsung Internet Android Full support 1.5


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