Screen sharing quality issue on Wayland + NVIDIA (2560×1440)

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Hi,

I’m having a problem with outgoing screen sharing on Jami Desktop under Linux.
I’m trying to use Jami as a Discord replacement while playing with small group of friends (like 2-4).

System:

  • CachyOS

  • KDE Plasma / Wayland

  • NVIDIA RTX 2080 Ti

  • Jami Flatpak 20260917.0

  • PipeWire 1.6.8

  • xdg-desktop-portal 1.22.1

  • xdg-desktop-portal-kde 6.7.5

My desktop resolution is 2560×1440, and I would like to keep it that way.

Screen capture itself appears to work correctly. PipeWire reports a 2560×1440 BGRA stream, and Jami receives the screen at the expected resolution.

However, the outgoing video seen by the other participant is heavily corrupted/pixelated, while incoming video streams from the other participant are perfectly fine.

I investigated the encoding side and noticed that Jami is using libx264 for the outgoing H.264 stream:

[libx264 @ ...] frame MB size (160x90) > level limit (8192)
[libx264 @ ...] MB rate (864000) > level limit (245760)

There are also VBV underflow messages.

The interesting part is that the Flatpak environment has NVIDIA NVENC support available. From inside the Jami Flatpak, FFmpeg reports:

h264_nvenc
hevc_nvenc

and I can successfully encode a 2560×1440@60 test source with h264_nvenc. nvidia-smi dmon also confirms that the NVIDIA encoder engine is actually being used.

Jami’s configuration already contains:

decodingAccelerated: true
encodingAccelerated: true

I also tried adding h264_nvenc to encoder.json, but Jami continued to use libx264.

So my question is:

Is H.264 hardware encoding with NVIDIA NVENC supported by Jami’s current Linux video pipeline, or is H.264 intentionally hard-coded to use libx264?

If hardware H.264 encoding is supported, is there a configuration option or codec negotiation setting that I’m missing?

If not, is there a recommended way to make Jami downscale the screen-share stream (e.g. 2560×1440 desktop → 1920×1080 stream) while keeping the desktop itself at 2560×1440?

I’d be happy to provide full Jami logs, PipeWire node information, or any other diagnostic information that would be useful.

Thanks!

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