Screen Recorder

Screen Recorder

Record the screen using ffmpeg with start/stop controls.

Requirements

• ffmpeg (pre-installed on most Linux distros)
• X11 or Wayland display server
• Optional: wf-recorder for Wayland, PulseAudio/PipeWire for audio

Instructions

Detect display server

echo $XDG_SESSION_TYPE  # "x11" or "wayland"

Full screen recording

# X11
ffmpeg -f x11grab -framerate 30 -i :0.0 -c:v libx264 -preset ultrafast -crf 23 output.mp4

# X11 with audio (PulseAudio)
ffmpeg -f x11grab -framerate 30 -i :0.0 -f pulse -i default -c:v libx264 -preset ultrafast -crf 23 -c:a aac output.mp4

# Wayland
wf-recorder -f output.mp4
wf-recorder -a -f output.mp4  # with audio

Region recording (X11)

# Get screen resolution first
xdpyinfo 2>/dev/null | grep dimensions || xrandr | grep '*'

# Record 1280x720 region at offset 100,200
ffmpeg -f x11grab -framerate 30 -video_size 1280x720 -i :0.0+100,200 -c:v libx264 -preset ultrafast output.mp4

Stop recording

pkill -INT ffmpeg      # Graceful stop (finalizes file)
pkill -INT wf-recorder
# ⚠️ Do NOT use pkill -9 — this corrupts the output file

Post-processing

# Compress
ffmpeg -i input.mp4 -c:v libx264 -crf 28 -preset slow -c:a aac compressed.mp4

# Convert to GIF (for sharing)
ffmpeg -i input.mp4 -vf "fps=10,scale=640:-1:flags=lanczos" -gifflags +transdiff output.gif

# Trim (start at 10s, duration 30s)
ffmpeg -i input.mp4 -ss 10 -t 30 -c copy trimmed.mp4

Edge Cases

• No display: Headless servers have no screen to record. Use virtual framebuffer (Xvfb) if needed.
• Multiple monitors: Specify geometry with -video_size and offset. Use xrandr to find monitor layout.
• Permission denied (Wayland): Some compositors restrict screen capture. Check compositor settings.
• Large files: Use -preset ultrafast during recording for low CPU, then compress afterward.
• Recording already running: Check with pgrep ffmpeg before starting a new one.

Security

• Screen recordings may capture sensitive information (passwords, tokens, private messages).
• Warn user before starting. Save to a private directory with restricted permissions.
• Delete recordings when no longer needed.