qTox can't share screen on wayland

[genodeftest]

OS: Linux: Fedora 25
qTox version: v1.6.0-38-g5921122
Commit hash: 5921122
toxcore: dcf2aaa53005060608353b9d66b9917fd7ed18a9 (2016-09-28)
Qt: 5.7.0

Reproducible: Always (by design)

Steps to reproduce

1. Open qTox
2. open preferences, section "Audio/Video"
3. as video device select "Desktop"

Observed Behavior

Preview is black, only showing the mouse pointer

Expected Behavior

Screen sharing should work.

Additional Info

Output on cli:

BAD!
BAD!
[x11grab @ 0x1db55a0] Stream #0: not enough frames to estimate rate; consider increasing probesize
[x11grab @ 0x1dbd6c0] Stream #0: not enough frames to estimate rate; consider increasing probesize
[swscaler @ 0x1dbf420] Warning: data is not aligned! This can lead to a speedloss

This bug is expected due to the current design changes while gnome-shell is ported to wayland API. Related info:

• KDE+KWin+Wayland: https://blog.martin-graesslin.com/blog/2016/11/from-window-killing-to-screenshot/
• Fedora bug report on screencast on wayland: https://bugzilla.redhat.com/show_bug.cgi?id=1299293
• Info in fedora wiki: https://fedoraproject.org/wiki/How_to_debug_Wayland_problems#Screen_capture_is_not_available_with_usual_apps
• GNOME DBus API for screencasts: https://git.gnome.org/browse/gnome-shell/tree/data/org.gnome.Shell.Screencast.xml

[zetok]

Is there a single API/lib that can be used to target all DEs?

[genodeftest]

As far as I know, no. But I've opened an upstream bug report: https://bugs.freedesktop.org/show_bug.cgi?id=98894

[stikonas]

At the moment if I click on the QComboBox to choose video device it crashes on Plasma Wayland session, I can't even choose any device.

Does it try to call any X-specific calls?

[Diadlo]

@stikonas Kind of

[genodeftest]

For now, there is no API on Wayland for doing screencasts correctly on all DEs. So I suggest disabling the feature until at least one API is stable.
@stikonas All of the screen casting "API" is X-specific.

[stikonas]

@genodeftest screen sharing API is of course X-specific (since preventing access to the screen is one of the points of compositors) but I would expect at least list of webcams to be shown on wayland instead of crashing.

[Diadlo]

@stikonas In the issue nothing about crash. Can you post backtrace or create new issue?

[stikonas]

I think porting to PipeWire would eventually be necessary to fix this.