Screen and window sharing over webrtc

Desktop
1

I’m on Fedora 31 with GNOME 3.34 (Wayland), using Jitsi in Firefox. I need to show the other participants what is on my screen and it works but there are a couple of caveats. I am planning on filing proper issues if needed but first I need to understand when/if I’m doing things wrong and what to eventually file issues against.

Window vs. whole screen

“Before” (hard to say when… 3.32 maybe? Earlier?) when I pressed the “share screen” in Jitsi, the Firefox authorisation popover used to offer me a list of available windows but now I only have the whole screen as on option.

I’m guessing this is due to the introduction of pipewire which doesn’t know how to share a specific window yet, or something atop pipewire that doesn’t know how to request it yet. Is that so? Is there an open issue I can subscribe to to follow development on that front?

Update (see comment 3): this is now implemented as of xdg-desktop-portal-gtk 1.5.0 which will be in Fedora 32.

Flow

  1. I click on the Jitsi screen sharing button, the Firefox authorisation popover pops over.
  2. I select the whole screen item in the combo, a GTK dialog opens (xdg-desktop-portal-gtk as I understand it)
  3. I select the screen I want to share and click the blue button (GTK dialog), dialog closes and the firefox popover now shows a thumbnail of that screen
  4. I click the blue button (Firefox popover), webcam image is still showing in Jitsi and the GTK dialog opens again.
  5. I select the screen I want to share and click the blue button (GTK dialog), a still image of my screen replaced my webcam image in Jitsi and the GTK dialog opens again.
  6. I select the screen I want to share and click the blue button (GTK dialog), my desktop in finally shown in Jitsi.

The whole situation is quite confusing. Why do I have to go through that GTK dialog three times? Should I file a bug against xdg-desktop-portal-gtk?

Screen selection

I have two identical monitors. In the GTK dialog I’m given a choice between two identical names with no means to know which is which.

image

Can we have overlay numbers like when arranging screens in the Settings panel? Should I file an issue against xdg-desktop-portal-gtk for that? Is that even technically possible?

Update (see comment 3): designs exist but are yet to be implemented.

Empty string choice

In the Firefox popover combo, I actually have a choice between whole screen or another item with no text. This item seems to behave exactly like whole screen. Is that a Firefox bug or is something sending wrong information to Firefox?

No full desktop

My desktop spans two monitors but I have to choose between one of them. Just as I would like to be able to share a single window, I would also have the option to share the whole desktop. What would such a feature request need to be filed against?

2

I think window sharing is supported by mutter these days (not sure about F31). So I would say it is more likely a case of Firefox not implementing that part yet.

Should be possible in principle, though I suspect more involved. In particular, one will need to actually display the numbers in the same way that gnome-control-center does (which is a separate dbus call to the shell to request it). So, implementation could be a bit odd and may require changes in mutter and gnome-shell.

Well, on wayland the only thing it could do would be that it uses the screenshot DBus API. So I suspect that is the old or fallback code in case you are on wayland but don’t have the pipewire based screensharing API (and portal).

3

I found a bit more information:

4

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.