Reframe a video, panning the crop to follow the motion
Crops into a new aspect ratio the way a camera operator would reframe a shot — the crop window pans to follow motion and detail instead of sitting locked to the centre. Runs entirely on this device. The original audio comes along unchanged if it's AAC.
Nothing is uploaded. Open your browser’s Network tab while you convert — you will see the file go nowhere.
No AI model — motion and detail, measured directly
Every output frame is drawn onto a tiny 64-pixel-wide analysis canvas, where two things are measured directly: how much each pixel changed since the frame before (motion), and how much it differs from its neighbours (edge detail). The weighted centre of that combined signal is where the crop wants to point. There's no face detector or machine-learning model doing the deciding, the same way Green Screen keys a colour rather than segmenting a subject with a model.
Why the pan doesn't jitter
A raw per-frame focus point is noisy on its own. It's smoothed with a fixed 0.35-second time constant, independent of frame rate, before the crop window is placed — that's what turns a twitchy estimate into a steady pan. The Tracking slider then blends between that smoothed point and the frame's plain centre, so a lower setting falls back toward an ordinary fixed crop if the tracking picks the wrong thing.
Why the audio sometimes doesn't survive
The video is genuinely re-encoded, because building the tracked crop means drawing new pixels — there is no wrapper trick for that. Audio doesn't need to be, so it's copied across as compressed packets exactly like the site's other video tools do, provided it's AAC. Anything else would need a decoder and an encoder this tool doesn't carry, so it's dropped rather than silently guessed at, and the plan says so before you convert anything.
Nothing is uploaded
Decoding, measuring motion, drawing the tracked crop and video encoding all happen in this page. There is no server here to send the video to, and the page's security policy blocks any connection to anywhere but this site. Here is how that is enforced.
How to auto-reframe a video
- Drop the video in. Nothing is sent anywhere — the whole file stays on this device.
- Pick a target aspect ratio and adjust Tracking until the plan and preview look right.
- Set the range, output size and frame rate, then press Convert and download.
All 39 HermitFile tools
Every one of them runs in your browser. Nothing you open is uploaded, and nothing is stored.