CODEWITHSUNDEEP
google-chromegoogle-chrome-extension
mike.schlanser
mike.schlanser

Reputation: 121

chrome.tabCapture.capture returned stream is undefined

I've got some js code in a chrome background extension of the following : 

function handleCapture(stream) {
    console.log('content captured');
    console.log("backround.js stream: ", stream);
    alert(stream);
    // localStream = stream; // used by RTCPeerConnection addStream();
    // initialize(); // start signalling and peer connection process
}

function captureCurrentTab() {
    console.log('reqeusted current tab');
    chrome.tabs.getSelected(null, function(tab) {
        console.log('got current tab');
        var selectedTabId = tab.id;
        chrome.tabCapture.capture({
            audio : false,
            video : true
        }, handleCapture);
    });
}

However, when this is ran, the "handleCapture" variable "stream" that is passed in is always undefined? Is this to be expected or is there something that I am missing here?

Also, I've confirmed that my manifest.json contains the capture permission and I am using chrome canary Version 31.0.1607.1 canary Aura.

Thanks, Mike

Upvotes: 5

Views: 5214

Answers (2)

Jamesgt
Jamesgt

Reputation: 605

You should probably provide some constraints to make it work. See: http://developer.chrome.com/extensions/tabCapture.html#type-MediaStreamConstraint

The capture param you provided is a MediaTrackConstraint, see: http://dev.w3.org/2011/webrtc/editor/getusermedia.html#mediastreamconstraints

that is also a simple JS object, where you should set some mandatory options, see: http://dev.w3.org/2011/webrtc/editor/getusermedia.html#idl-def-MediaTrackConstraints

So the following should help, if you set all the needed settings in mandatory object:

chrome.tabCapture.capture({
    audio : false,
    video : true,
    videoConstraints: {
        mandatory: {
            width: { min: 640 },
            height: { min: 480 }
        }
    }
}, handleCapture);

Upvotes: 2

bbaldino
bbaldino

Reputation: 404

I had this same issue when I was trying to drive a tabCapture purely from a background script, I found this on the tabCapture reference page:

Captures the visible area of the currently active tab. This method can only be used on the currently active page after the extension has been invoked, similar to the way that activeTab works. Note that Chrome internal pages cannot be captured.

My understanding is that this means you need to drive it from a browserAction for your extension, like so:

chrome.browserAction.onClicked.addListener(function(request) {
    chrome.tabs.getSelected(null, function(tab) {
        chrome.tabCapture.capture({audio: true, video: true}, callback);
    });
});

That's what worked for me.

Upvotes: 2

Related Questions