Audio of the tab disappear while capturing tab using TabCapture API - google-chrome-extension

Question

I am testing a Tab Capture API to record audio of web page that contains a text to speech flash object. while recording a web page the playback audio disappear but sounds OK in the recorded file.
I am using the following MediaStream constraint to record video and audio.
var MediaStreamConstraint = {
audio: true,
video: true,
videoConstraints: {
mandatory: {
chromeMediaSource: 'tab',
minWidth: 640,
maxWidth: 640,
minHeight: 420,
maxHeight: 420
}
}
};
am i missing something in the stream constraint or there is some other solution to the problem?

Answer 1

As others have said, playing the audio from the captured MediaStream in the callback works:
chrome.tabCapture.capture(MediaStreamConstraint, gotStream);
function gotStream(stream) {
window.audio = document.createElement("audio");
window.audio.src = window.URL.createObjectURL(stream);
window.audio.play()
}

Answer 2

Keep in mind to grant permissions in manifest file
"permissions": [
"tabCapture",
"activeTab",
...
],
The background.js should be something like this:
var recorder = new MRecordRTC();
function handleCapture(stream) {
recorder.addStream(stream);
recorder.mediaType = { video: true, audio: true };
recorder.startRecording();
}
var MediaStreamConstraint = {
audio: true,
video: true,
videoConstraints: {
mandatory: {
chromeMediaSource: 'tab',
minWidth: 640,
maxWidth: 640,
minHeight: 420,
maxHeight: 420
}
}
};
function captureCurrentTab() {
chrome.tabCapture.capture(MediaStreamConstraint, handleCapture);
}
function stopCapturing() {
// stops the recording and save audio and video
}
If these are not the case, could you please attach more related codes since the codes you attached look good with me.

Answer 3

In your background script's handleCapture function, try this to continue playback:
var audio = new Audio(window.URL.createObjectURL(stream));
audio.play();

Answer 4

only add the next lines
window.audio = document.createElement("audio");
window.audio.src = window.URL.createObjectURL(stream);
window.audio.play()