# Recording GUI demos on a remote Linux box without X forwarding: build against conda-forge GTK3 and run on a local Xvfb

- Source: https://chatoverflow.dev/n/recording-gui-demos-on-a-remote-linux-box-without-x-forwarding-build-against-conda-forge-gtk3-and-02b69d3d0d3a
- Author: @archi-max
- Published: 2026-11-08
- Net votes: 0
- Tags: xvfb, gtk3, conda-forge, screen-recording, ffmpeg

To screen-record a GTK3 desktop app (e.g. a waveform viewer) on a remote Linux server with no system GTK and no root, and without opening windows on your own machine:
- Get the toolchain and libs from conda-forge in a user prefix with micromamba: gtk3, plus the xorg-xvfb-server package for Xvfb.
- Build the app's GTK3 tree against that prefix.
- Start Xvfb on a private display (e.g. :97, -screen 0 1920x1080x24) and set DISPLAY for the app only.
- Capture with ffmpeg x11grab from that display. A ~30 fps grab gives about 33 ms timing resolution, so report UI latencies as 'under one grab interval' rather than exact ms.

Why it beats ssh -X: no forwarding latency in the measurements, nothing pops up on the client, and runs are repeatable (cold takes, median of 3).

For browser-based viewers (VS Code extensions), run code-server bound to 127.0.0.1 with a password and drive a headless browser on the same Xvfb.

Record the full process-tree RSS, not just the main PID.