Can’t record screen on Plasma when using Flatpak or Snap

sblantipodi · May 6, 2026, 8:49am

Hi, I hope someone can help me.
The same snap/flatpak that runs on Ubuntu 25 does not run on Ubuntu 26.

the app is a screen recorder one that uses GStreamer + pipewire X11 + dbus portal

Do you see anything obvious that could prevent it from working on Ubuntu 26?

snapcraft/snap/snapcraft.yaml

c47d5f0e1

name: fireflyluciferin
title: Firefly Luciferin
base: core24
version: '2.17.21'
summary: Ambient lighting software
description: |
  Ambient Lighting or Bias Light is a technology that enhances your viewing experience by projecting colored lights onto the wall behind
  your TV/Monitor, matching the colors on the screen. This creates a more immersive and engaging atmosphere, making your favorite shows,
  movies, and games feel even more captivating.

website: https://github.com/sblantipodi/firefly_luciferin
contact: https://github.com/sblantipodi/firefly_luciferin/issues
issues: https://github.com/sblantipodi/firefly_luciferin/issues
source-code: https://github.com/sblantipodi/firefly_luciferin
icon: fireflyluciferin.png
license: GPL-3.0

grade: stable
confinement: strict
platforms:

This file has been truncated. show original

The issue happens with KDE 6.4.4 — it works fine on GNOME.
It seems that GStreamer is not able to capture the screen on KDE, while it works on GNOME.

I’m using GStreamer and PipeWire to capture the screen, and I need to open a portal on D-Bus to do it.
However, this worked correctly on Ubuntu 24–25 on both GNOME and KDE.
On Ubuntu 26 it works on GNOME but not on KDE.

If I run the app natively outside of snap/flatpak, it also works fine on KDE on Ubuntu 26.

This is the app

ogra · May 6, 2026, 10:25am

There is a link on that page where you can report issues to the packager:

github.com/sblantipodi/firefly_luciferin/issues

sblantipodi · May 6, 2026, 12:54pm

I’m the packager
and I would like to fix the issue in my package but I don’t know what to fix because as I said the behaviour is weird.

On Ubuntu 25 everything works well.

On Ubuntu 26

it works on Gnome (no problem at all on gnome)
it works on KDE if not using SNAP, it doesn’t work on KDE if using SNAP.

The screen capture began but I don’t receive the captured image, it’s like if something is lost between the dbus portal and pipewire…

ogra · May 6, 2026, 3:29pm

LOL, sorry I didn’t notice that you are the packager (I might have had you asked in forum.snapcraft.io, I rarely see snap packaging questions around here)

There is a debug setting for the kde portal, I’d try setting:

QT_LOGGING_RULES=‘xdg-desktop*.debug=true’

…in your session and see if something shows up in the journal…

sblantipodi · May 6, 2026, 7:34pm

thanks for the answer ogra, at the end I found the issue.

Kwin changed the maximum buffer size from 1 to 16

to 1 to 4.

https://invent.kde.org/plasma/kwin/-/merge_requests/5502

adjusting the buffer size on my gstreamer pipeline fixed my issue.

system · May 7, 2026, 1:34pm

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