tdesktop Make screencasting with audio work on Linux

Steps to reproduce

Try sharing video
There is no share audio button at all

Expected behaviour

A button to share audio

Actual behaviour

No ability to share audio at all. No matter X11 or Wayland

Operating system

Linux

Version of Telegram Desktop

4.8.7

Installation source

Other (unofficial) source -> From Manjaro repo

Crash ID

No response

Logs

No response

Aug 12 '23 14:08 damnkrat

@Aokromes Can you provide a link to the duplicate? I couldn't related issue before creating new one

Aug 12 '23 14:08 damnkrat

I don't think this was reported before. Although there's no contributor who can implement that so it's unlikely to appear...

Aug 13 '23 04:08 ilya-fedin

it was, i remember it reported, but hard to find xd

Aug 13 '23 04:08 Aokromes

I see there were questions about why this is not implemented (#16730, #17163) but no bug report about that. Although I'd say this should be a feature request.

Aug 13 '23 05:08 ilya-fedin

Also both are marked as closed, we need to open one of the questions, or without that, do this feature

Aug 14 '23 14:08 damnkrat

I don't see a reason to open those questions, they're answered

Aug 14 '23 20:08 ilya-fedin

I'm highly doubt the feature will be implemented, with an issue or without. But you can try to open a new feature request, hope @Aokromes won't close anymore.

Aug 14 '23 20:08 ilya-fedin

I assume Telegram is using the XDG portal for screencasting? If so then sending audio with application/system capture is currently unsupported (which is why it doesn't work in Discord or OBS either). There has been some movement on this recently, I'd recommend keeping watch on this issue (and for the Telegram devs working on Linux it might be a good idea to contribute their own two-cents there).

Nov 17 '23 08:11 ReillyBrogan

I assume Telegram is using the XDG portal for screencasting?

WebRTC.

There has been some movement on this recently, I'd recommend keeping watch on this issue (and for the Telegram devs working on Linux it might be a good idea to contribute their own two-cents there).

I'm not sure that would help. WebRTC has no "capture system audio" API and if this would become a part of the screencasting API then it would become unimplementable for tdesktop as currently the portal session is managed by WebRTC and tdesktop doesn't have access to its handles so it would be unable to speak to the portal directly and WebRTC doesn't have an API for this.

Right now it's implementable as application has full access to PipeWire/PulseAudio/ALSA. The only problem is application uses OpenAL for audio and OpenAL doesn't have API for this feature either so this feature has to be implemented with native code while tdesktop project has no one with PipeWire/PulseAudio/ALSA experience to implement any backend (not even speaking about every) for Linux. I guess OBS and Discord having the same problem: they don't have experience with Linux audio APIs and they always have much more prioritized tasks to spend time on rather than learning the zoo of Linux audio APIs.

I know there's https://github.com/maltejur/discord-screenaudio/blob/master/src/virtmic.cpp which could be used as a base but still someone has to spend time to port the implementation to tdesktop...

Nov 17 '23 09:11 ilya-fedin

some additional info about screen sharing with audio on wayland + pipewire

works by default in obs
works by default in discord-screenaudio
works by default in vesktop, audio source must be selected, no audio selected by default
here is a guide how to make it work in firefox
here is a guide how to make it work in chromium

hope we get this feature in telegram soon