Before and after: Flow watermark removal on moving video

Three openly licensed clips, at 1080p, 720p and 1080p portrait. Each has the Gemini diamond blended in the way Flow adds it, then removed by this site’s engine. The corner is enlarged so you can judge the result while the picture moves. Download the watermarked files and run them through the tool yourself.

Try it on your own clip

Surf line, 1080p landscape

With the Gemini diamondCleaned by this tool

Bottom-right corner of the 1920×1080 frame, enlarged 2×. Breaking waves run through the corner the whole time, so the patch under the diamond changes on every frame.

Size: 1920×1080 (1080p landscape), 25 fps, 8.6 s, H.264 with audio
Files: Watermarked MP4 (5.9 MB) · Cleaned MP4 (5.6 MB)
Source: Ocean waves at Lækjavik beach, Iceland by Alexander Grebenkov, Wikimedia Commons, CC BY 3.0. Watermark added and removed for this demonstration.

Surf line, 720p landscape

With the Gemini diamondCleaned by this tool

Bottom-right corner of the 1280×720 frame, enlarged 3×. The same scene at 720p, where the diamond is 48 px instead of 72 px.

Size: 1280×720 (720p landscape), 25 fps, 8.6 s, H.264 with audio
Files: Watermarked MP4 (3.3 MB) · Cleaned MP4 (3.1 MB)
Source: Ocean waves at Lækjavik beach, Iceland by Alexander Grebenkov, Wikimedia Commons, CC BY 3.0. Watermark added and removed for this demonstration. Scaled down from the 1080p original with ffmpeg (Lanczos) before the mark was added.

Shoreline at dusk, 1080p portrait

With the Gemini diamondCleaned by this tool

Bottom-right corner of the 1080×1920 frame, enlarged 2×. A handheld shot that pans along the beach, so the wet sand under the mark changes from frame to frame.

Size: 1080×1920 (1080p portrait), 30 fps, 8 s, H.264 with audio
Files: Watermarked MP4 (9.0 MB) · Cleaned MP4 (8.3 MB)
Source: The blue sky kisses the green ocean, as I stand on the shore of little brown sand, watching evening melt into waves by Mathanprasath K, Wikimedia Commons, CC BY 4.0. Watermark added and removed for this demonstration. First 8 seconds of the original clip.

How these examples were made

Each source clip is an openly licensed video from Wikimedia Commons (credits below each example).
The Gemini diamond is blended onto every frame with the formula Flow uses for its mark (shown = white × opacity + original × (1 − opacity)), at the size, position and opacity we measured on original Flow downloads: 72 px at 1080p and 48 px at 720p, bottom-right. That watermarked file is saved as H.264 MP4 and is the one you can download.
The watermarked file is decoded again and every frame goes through the engine's processFrame function, the same code that runs in your browser on this site. Here it ran in Node.js with ffmpeg decoding and encoding the frames; on the site, your browser's WebCodecs does that part.
The comparison clips crop the bottom-right corner of both files and enlarge it, so a leftover outline would be easy to see.

The engine and our changes to it are described on the about page, with a readable copy of the frame-processing code. The still photos on the home page were made the same way.

Questions

Are these real Google Flow exports? No. They are openly licensed clips with the Flow diamond added using the profile we measured on Flow downloads. We do not publish other people’s Flow videos. To judge the tool on a real export, try one of your own clips: checking a file is free and shows whether it can be processed.

How do results on real Flow downloads compare? On the real 720p Flow downloads we tested, the corner came out clean. On a real 1080p download with a dark, flat corner, a faint outline was visible when zoomed in 2–3×, and not at normal size. Bright and textured corners hide it completely.

Can I test these files myself? Yes. Download a watermarked file, drop it into the remover, and compare the result with the cleaned file from this page. Nothing is uploaded either way.