Drop in the file that will not play and it tells you exactly how many frames survived. One file is all it needs. It is free, it works on any computer, and nothing is uploaded.
Not sure this is your failure? The three things “corrupted” usually means, and how to tell them apart.
Most recordings do not need a second clip at all — why, and how to tell whether yours does.
Your file never leaves this page. Only the first and last megabyte are read, because that is where the markers that decide the answer live, so a 60 GB card dump is no slower than a short clip. There is no upload, no account and no sign‑in, and the page works with the network switched off once it has loaded.
The good case, and by far the most common one. A recording is written to the card as
it happens, but the index that tells a player where every frame lives is written last,
when you press stop. A flat battery, a pulled card or a crash means the footage is all
there and the index never got written. Players report
moov atom not found and refuse to open the file. The frames can be found
again and the index rebuilt.
Whatever is wrong, it is not the missing‑index failure, so rebuilding the index would not help. The likely causes are a partially overwritten recording, a card that is failing, or a codec your player does not support. Try VLC before assuming the worst: it opens a great deal that other players refuse.
The file is too small to contain a recording. The camera created it and never wrote the video into it. Nothing can be rebuilt from an empty container, and the only remaining route is card‑level recovery software that scans for orphaned data. Stop using that card immediately if you go that way.
Whatever the answer, stop writing to the card. Every new recording risks landing on top of the one you are trying to get back. Copy the whole card to a drive first and work from the copy.
Most recordings state their own codec settings inside the video, so one file is all this needs. They are read that way here, in the H.264 and the HEVC modes alike, GoPro included.
An iPhone is read a third way and also needs nothing else. About ten seconds into a take, iOS writes a complete index into the middle of the recording so that a phone dropped mid‑shot still has one. If your take ran longer than that, the count below is the phone's own, frame for frame, with the sound counted too.
For the rest the settings have to come from a working recording made by the same camera in the same mode. The page says so when that happens rather than guessing. Any clip will do, it does not need to be related to your footage, and a few seconds recorded now is plenty.
Cinesalve rebuilds the index and gives you a playable recording. Every frame lands at the byte offset and size the camera originally wrote — measured that way against footage from GoPro HERO5 through HERO8, Karma, Fusion, MAX, a DJI Mavic 3 Pro, an iPhone 11, a Canon EOS 5D Mark II and Apple's own muxer.
It is a Mac app, it runs entirely on your machine with no account and no upload, and it is $69 once: every Mac you own, for good, no subscription.
The GoPro models in the table state their own codec configuration inside the video, in both the H.264 and the HEVC modes the range records, so the app recovers them from the damaged file alone. Recordings that do not carry it ask for any clip from the same camera that plays, and read it from there.
Describe the camera and what happened to cinesalve@proton.me (or the contact form) and you will get a straight answer, including when the answer is that the footage is gone. Files from cameras this has not met yet are genuinely wanted.