FFmpeg Has a Mandelbrot Generator Built In

Most people use FFmpeg to convert video files. Few know it ships with a virtual device system called lavfi that generates video from pure math — no input file, no external tools, nothing to install. It’s already on your system.

Check Your FFmpeg Install

ffmpeg -version

If FFmpeg is installed, lavfi is included. That’s all you need.

Generate a Mandelbrot and Save It

ffmpeg -f lavfi -i "mandelbrot=size=640x360:rate=24:maxiter=100" -t 30 -c:v libx264 -crf 23 mandelbrot.mp4

What each parameter does:

• size=640x360 — resolution, keep it low for fast renders
• rate=24 — 24fps
• maxiter=100 — iteration depth per pixel, this is your biggest performance lever
• -t 30 — 30 seconds of output then stop
• -crf 23 — standard x264 quality

Watch the fps counter in the terminal. On a CPU-only machine maxiter=100 keeps it moving. Drop to 50 if it’s still slow. Raise to 500+ for more fractal detail at the cost of render time.

maxiter is the iteration ceiling per pixel — how hard it tries to determine whether a point escapes to infinity. At low zoom levels it barely matters. As the animation zooms deeper into the fractal boundary, low maxiter causes the edges to go flat and blocky. If you’re rendering a zoom sequence, raise it proportionally.

Play It Directly — No File Written

ffplay -f lavfi "mandelbrot=size=640x360:rate=24:maxiter=100"

ffplay is FFmpeg’s built-in player. Live output, no mp4, no VLC needed. Kill with q.

Add Color Rotation

ffmpeg -f lavfi -i "mandelbrot=size=640x360:rate=24:maxiter=100" \
  -vf "hue=h=t*20" -t 30 -c:v libx264 -crf 23 mandelbrot_color.mp4

hue=h=t*20 rotates the color spectrum over time as a filtergraph applied on top of the raw lavfi output. t is elapsed time in seconds.

Zoom Into the Boundary

The default animation zooms toward a fixed point. You can control where it zooms and how fast:

ffplay -f lavfi "mandelbrot=size=640x360:rate=24:maxiter=500:start_x=-0.7435:start_y=0.1314:start_scale=3.0:end_scale=0.001"

start_x and start_y set the target coordinate in the complex plane. start_scale and end_scale control zoom range — smaller end_scale means deeper zoom. The boundary region around -0.7435, 0.1314 is a classic target: high detail, long zoom runway.

The Bigger Point

FFmpeg’s lavfi system includes other sources worth exploring:

ffmpeg -f lavfi -i testsrc2 -t 10 test.mp4        # test pattern
ffmpeg -f lavfi -i "sine=frequency=440" -t 5 tone.wav  # pure sine wave

The tools that do the actual work have been on your system the whole time. The GUIs were just hiding them.

Tested on Debian, CrunchBang++. FFmpeg 6.x. CPU-only, no GPU required.