Recovers "human-only" text that is hidden in the motion of a noise video.

Input clip (play it)	Decoded

Pause the clip on any single frame and it is just static:

The text is not hidden in brightness, it is hidden in motion. A field of black-and-white noise scrolls behind the frame. Inside the letters it scrolls up, everywhere else it scrolls down. Every individual frame is the same uniform noise, so a screenshot shows nothing. Only when the video plays does the opposing motion draw the letters out.

So this is not an AI-proof font. It is a screenshot-proof one. Anything that sees more than a single frame, including this decoder, reads it straight through.

For each pair of consecutive frames it correlates them shifted up and down by a few pixels. Upward motion counts positive, downward negative. One frame pair is almost pure chance, but summing over the whole clip and pooling over small blocks makes the sign reliable: positive blocks are the text, negative blocks are the background. Threshold the sign and you have the mask.

That is the whole method, about 30 lines in ghostbuster/decoder.py.

pip install -r requirements.txt

from ghostbuster.decoder import decode_ghost_video

mask = decode_ghost_video("clip.mp4", velocity=2, num_frames=60)
# mask: binary image (0/255), white where text was detected

Web app (upload a clip in the browser):

python app.py          # http://127.0.0.1:8000

Regenerate the demo assets and a sample assets/demo.mp4 to try:

python scripts/make_demo.py

Run the tests:

pytest

• velocity - pixels per frame the text and background move in opposite directions, usually 1 to 3. If a clip does not resolve, sweep this.
• num_frames - frames to read. More frames give a cleaner result. 30 to 120 is a good range.
• block_size - spatial pooling window, default 12.

• Heavy video compression smears the noise and hurts recovery. Test on the original clip, not a re-encoded download.
• If velocity is large relative to the noise grain you can hit temporal aliasing and the sign flips. Downscale or read fewer frames if that happens.