User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:29.0) Gecko/20100101 Firefox/29.0 (Beta/Release) Build ID: 20140506152807 Steps to reproduce: Call mozGetUserMediadevices(); with parameters - contraints, successCallback and errorCallback. Actual results: The successcallback or errorcallback for mozGetUserMediaDevices is not called until getUserMedia() has been called once before. Expected results: Irrespective of whether one has used getUserMedia before or not, function mozgetUserMEdiaDevices should call either successCallback or errorCallback. Please specify if it's defined to work upon getUserMedia call.

mozGetUserMediadevices() is internal - see Bug 793446, comment 3 - and is part of the implementation of getUserMedia(). I don't believe it is meant to function independently. Not to be confused with getMediaDevices() http://dev.w3.org/2011/webrtc/editor/getusermedia.html#navigatorusermedia which doesn't exist yet. We could perhaps repurpose this bug for this, if we don't have one already (I couldn't find it).

(In reply to Jan-Ivar Bruaroey [:jib] from comment #1) > mozGetUserMediadevices() is internal - see Bug 793446, comment 3 - and is > part of the implementation of getUserMedia(). I don't believe it is meant to > function independently. Some more context here: - Mayank's code is running in chrome, not web-content. - The bug he is working on is bug 975542, and he's trying to disable a button in the UI if there's no camera connected to the computer. Is there any way to do this currently?

Does this help?

Comment on attachment 8424849 [details] [diff] [review] Best guess fix Review of attachment 8424849 [details] [diff] [review]: ----------------------------------------------------------------- mozGetUserMediaDevices still seem to be dependent on gUM. I tried using it without gUM still the results are same as described in previous comments. Maybe as Jan-Ivar said it isn't meant to function independently.

Comment on attachment 8424849 [details] [diff] [review] Best guess fix Thanks for looking into this, the patch doesn't help unfortunately. Here are detailed steps to reproduce to help debugging: 1. Set devtools.chrome.enabled to true in about:config 2. Tools -> Web Developer -> Browser Console 3. Tools -> Web Developer -> Scratchpad 4. In the Scratchpad's menu, Evnrionment -> Browser 5. Paste this in the scratchpad: navigator.mozGetUserMedia({audio: true}, function () {window.console.log("GUM success!");}, function () {window.console.log("GUM Error!");}); navigator.mozGetUserMediaDevices( { video: false, audio: true }, devices => { window.console.log("Number of audio devices: " + devices.length); }, error => { window.console.log("Error!");} ); 6. Select the gUMD call, press Command+R and observe that nothing is logged in the Browser Console. 7. Select the gUM call, press Command+R. "GUM success!" should be logged to the Browser Console. 8. Select the gUMD call again, press Command+R and see that it now logs "Number of audio devices: <some number>"

The desired behavior should be covered by navigator.mediaDevices.enumerateDevices().