A clip that won't play is usually a container problem: a broken index or moov atom, a missing header, or an interrupted download or transfer. mov.repair first remuxes the streams to rebuild the container and timestamps — fast and lossless — and re-encodes only if the streams themselves are damaged, handing back a clean, playable .mov. Free, online, no watermark.
Why MOV files get corrupted
MOV files break when a recording or transfer is interrupted before the file is finalised, when the index/moov is missing or misplaced, or when a few packets are damaged. Remuxing rebuilds the container around the good streams; re-encoding rescues the rest.
What repair can and can't recover
Repair works well for interrupted downloads, broken headers or indexes, and files that open in one program but not another. A file missing its moov/index or cut off mid-stream may only partly recover; the tool rebuilds what's present rather than pretend the rest is there.
The missing moov atom
QuickTime .mov files keep an index (the moov atom) that some cameras write last. If a recording stops early it can be missing or misplaced, so the file won't play. Remuxing rebuilds the container and timestamps around the recorded video.