Re: getDisplayMedia() and system audio

On Wed, Sep 5, 2018 at 8:22 PM, Martin Thomson <martin.thomson@gmail.com>
wrote:

> On Thu, Sep 6, 2018 at 10:11 AM Bernard Aboba
>
> There is probably some role for consent there, but I agree that this
> should be as narrow as the selection.  To vary from that would require
> some exceptional consent, in an area that is already a minefield.
>

There is also an implementation minefield since there is no one-to-one
correlation between audio sources and windows. Audio is played by the
process and its relationship to a specific window is not always obvious.
Even if you limit audio capture to a specific process, it is not trivial to
capture it. There are no standard APIs for this. Audio capture from a
process on most of the operating systems requires some sort of hack, like
dynamic library injection. The most reliable method is to install a special
driver that creates a virtual output device which maps to a virtual input
device. Then the application needs to be configured to play into the
virtual output driver and virtual input driver can be used as WebRTC audio
source. One example of such setup are Virtual Audio Cables (
https://en.wikipedia.org/wiki/Virtual_Audio_Cable). This means that for
people who needs this now, there is a work around already available.
Implementing something nice with an interface, which is safe to obtain
consent and be used in a browser, is probably not currently possible.

Regards,
_____________
Roman Shpount