feat: allow patching video & audio devices into screen share

[ryanccn]

This is useful when loopback audio drivers or applications, such as BlackHole, are already installed.

[ryanccn]

@Vendicated I need some help here, currently using a video device errors with TypeError: Video was requested, but no video stream was provided. Testing seems to indicate that patching isn't successful? The overridden navigator.mediaDevices.getDisplayMedia never gets called.

[RinLovesYou]

Behavior on linux is rather unpredictable.

Starting a stream using camera

Initial result is this error, and no stream starting.

Afterwards, pressing the "Go Live" button will immediately start the stream using the previously selected camera. Window picker does not appear.

[LuminaSapphira]

Doesn't allow picking video patch on wayland - the modal is entirely skipped since the selection is done with the desktop portal instead of in the app.

[Vendicated]

a lot has changed about the code since and now it has global state that it applies inside a getUserMedia patch. that'll likely solve your issues of only applying once! could you please rebase based on that?

[t1stm]

sorry for my useless comment, but this will make screen-sharing games on X11 finally bearable using my small tool (edit: i am talking as an NVIDIA proprietary driver user).

if the dev of this pr cannot currently / doesn't have the time to rebase it, would it be possible for me to do it?

[ryanccn]

I rewrote the implementation from scratch based on the latest code and added back audio device patching support; video device patching is on the roadmap as well :>

[t1stm]

i have been dailying this PR for three days now and I haven't encountered any issues yet. maybe a better UI can be implemented later, but for now i think it's OK. (huge thanks for the dev since this is what i personally needed for streaming in discord)