1183510 - Don't stop audio playback on HTMLMediaElement::CaptureStream()

Status: RESOLVED DUPLICATE of bug 1178751

(Core :: Audio/Video: Playback, defect, P5)

Description

[Andreas Pehrson [:pehrsons]]

As of today, having a MediaDecoder send audio and video to a MediaStream stops the audio playing to speakers.

HTMLMediaElement::CaptureStream shouldn't stop audio playback of the media element per its spec, http://w3c.github.io/mediacapture-fromelement/.

However, WebAudio's MediaElementAudioSourceNode should still stop audio playback of the media element per the WebAudio spec, http://webaudio.github.io/web-audio-api/#idl-def-MediaElementAudioSourceNode


A discussion on solving this started in bug 1172394, which later became invalid. Let's continue here.

Comment 1

[Andreas Pehrson [:pehrsons]]

Bringing the discussion over here.

(Maire Reavy [:mreavy] (Plz needinfo me) from comment #10)
> (In reply to Andreas Pehrson [:pehrsons] (Telenor) from comment #6)
> > I put together some cases and solution ideas in [0] Maire, do you want to
> > check it out before inviting people?
> > 
> > [0] https://etherpad.mozilla.org/capturestream-cases
> 
> Thanks, Andreas.  Your writeup is clear and concise and much appreciated.  
> 
> Paul - can you read over Andreas's writeup, in particular his proposed
> solutions and weigh in on which one you prefer.
> 
> NeedInfoing roc and jesup for their awareness and suggestions.  Thanks

(Randell Jesup [:jesup] from comment #11)
> Seems reasonable, thanks.  I'm tempted by the c++ 'polyfill' idea

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I'm not sure what the question is. I'm fine with implementing this as specced, and I don't think it will be hard to do; we just need an internal HTMLMediaElement::CaptureStream method that takes a parameter indicating whether to stop audio playback.

Comment 3

[Paul Adenot (:padenot)]

Yeah same, I generally agree that this is what we should do, and an additional enum parameter in CaptureStream sounds good to me.

Comment 4

[Ralph Giles (:rillian)]

We can't tell how urgent this is. Can you provide a usecase?