User Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.80 Safari/537.36 Steps to reproduce: I would want to record my full-browser screen using MediaStream API, On passing the stream to the API , I pass as the CanvasCaptureMediaStream oblect, which firefox couldn't record that object. I get the CanvasCaptureMediaStream object with the following syntax, canvas.captureStream().

Can you please provide a test page or url where this issue can be reproduced?

<script> var elementToShare = document.body; document.getElementById('stop').disabled = false; var options = { mimeType: 'video/webm' }; var recorder = new CanvasRecorder(elementToShare); document.getElementById('start').onclick = function() { recorder.record(); }; document.getElementById('stop').onclick = function() { recorder.stop(function(blob) { console.log(blob); var url = URL.createObjectURL(blob); var video = document.createElement('video'); video.src = url; video.setAttribute('style', 'height: 100%; position: absolute; top:0;'); document.body.appendChild(video); video.controls = true; video.play(); }); }; </script> This is the script code that attached to a document with start and stop button. For this you have to attach RecordRTC.js and Screenshot.js which I have attached with this bug. On executing after setup it throws an error "The UA cannot provide the codec or recording option that has been requested. error { target: MediaRecorder, isTrusted: true, name: "GenericError", currentTarget: MediaRecorder, eventPhase: 2, bubbles: false, cancelable: false, defaultPrevented: false, timeStamp: 1624.1685901254423, originalTarget: MediaRecorder, explicitOriginalTarget: MediaRecorder }" and also while retaining the blob url it throws a warning as "Media resource blob:http://localhost/365d88e6-6c5d-4955-9f45-03a8cce461cd could not be decoded." and inside the video attribute it shows the error as "Video can't be played because the file is corrupt" The discussion with the author of RecordRTC is in the below link https://disqus.com/home/discussion/recordrtc/class_canvasrecorder/#comment-2354729296 And from that discussion the conclusion is "Firefox isn't capable to record CanvasCaptureMediaStream object through MediaRecoder API". The CanvasCaptureMediaStream Object is obtained using canvas.captureStream()

Refer Comment2 for this usage

Comment on attachment 8686685 [details] RecordRTC.js Refer Comment2 for this usage

(In reply to Sebastian H. [:aryx][:archaeopteryx] from comment #1) > Can you please provide a test page or url where this issue can be reproduced? Refer Comment2

It's not clear to me if this is a canvas bug or a webrtc bug. Maire what does this look like to you?

What version of Firefox? pehrsons modified MediaRecorder recently to allow it to record canvas streams (differing buffertypes). See Bug 1182426. This is on 44 and 45 (Developer Edition/Aurora and Nightly).

This is definitely a Media Recorder issue, and as Randell says in Comment 9, this is likely fixed in later versions of Firefox. If the reporter could verify the fix, that would be much appreciated.

In Firefox browser , MediaRecorder API doesm't record CanvasCaptureMediaStream. This is my issue. My aim is to record the browser screen.

It works on Firefox Developer Edition v44.0a2 and doesn't work on Firefox v42.0. Any idea when the firefox will get update to support the CanvasCaptureMediaStream Object Recording as that of Firefox Developer Edition v44.0a2. Will the change in Firefox Developer Edition moved to Firefox future releases?

Yes, 44 will go to release in around 9 or 10 weeks. Thanks for testing the fix!