WebGL audio recording

Hello Unity connoisseurs!
I am trying to provide recording functionality (save gameplay as video file) for my WebGL game.
I can easily record video stream (via javascript plugin) as
let canvasStream = canvas.captureStream();
But I fail to record audio :frowning:
I can go with
stream = await navigator.mediaDevices.getUserMedia(constraints);
But I donā€™t like this method. It creates popup, interrupting the game. Iā€™d like it to go smoothly, without interruption.
I see the WEBAudio object created on the page with WEBAudio.audioInstances, WEBAudio.audioContext, etc. But I failed to get audio stream from there.
No errors logged and no audio in my recording. Just video.
Appreciate your help.
PS: sorry, this is the only place where I managed to create the post. Anywhere else I was getting ā€œBeginner tag can not be used. Remove itā€.
Remove how? From where???