Not when the map was never written. ffmpeg needs it to read the file. You need a program that builds a new map from a sample clip, such as untrunc.

The file is the right size and still won't open?

Then the recording was cut off and the footage is inside. Go back to the steps above.

I have no technical background. Can I do this myself?

Yes. The program works like any other: open it, pick two files, press a button. Nothing to type. What needs attention is the size check at the start and the video check at the end.

“moov atom not found” on a video file: what it means and how to fix it

A Windows terminal running ffprobe on C2000.RSV: the lines moov atom not found and Invalid data found when processing input, in red — The message as ffprobe prints it for a recording that was cut off before the camera finished it.

In short

What happened: the file is missing a small part called moov, the “map” that tells a player how long the video is and where each frame sits. The camera writes it at the end of the recording, and if it shut off before, it was never written.
What not to do right now: don't format the card, don't keep shooting on it, and don't try to “convert” the file. A converter can't read a file with no map.
What to do: first check the file arrived complete. If it did, build it a new map with a healthy clip from the same camera and a free program. Steps below.
Don't want to deal with it? Send me the file. The check is free, and if I couldn't recover it, you get your money back. How to send it.

First: is the file complete?

The same message shows up in two opposite situations, so this is the first check.

The file came straight off the card: the recording was cut off, the footage is inside, and it can be repaired. Go to the steps below.
The file came by download, WeTransfer, Drive sync or a copy: compare its size with the original. If it's smaller, or stops at exactly a round number of megabytes, the transfer broke off and the end of the file is empty. No program builds footage that never arrived. Ask for the file again. One that came to me: a file that stopped at exactly 1,050 MB. When I checked it, 88 percent of it was empty.

What to do, step by step

Copy everything to the computer. The broken file, and while you're at it a healthy clip from the same card. From now on work only on the copies. The card stays aside.
Prepare a “sample clip”. A healthy recording from the same camera at exactly the settings the broken file was shot with: same resolution (4K, say), same frames per second (25, 50 or 100), same recording quality, and the same compression type (H.264 or HEVC; DJI and GoPro can switch between the two in their settings). Simplest: a clip you shot the same day, just before or after the broken one, without changing settings in between. The clip you copied from the card usually fits. If there isn't one, put a card in the camera, lens cap on, and record 30 seconds.
Run a free program called untrunc. It takes the map from the healthy clip and builds a new one for the broken file. Download it here (Windows. A normal program with buttons, nothing to type). On the page that opens, download untrunc_x64.zip, unzip it, and run untrunc-gui.exe (not untrunc.exe, which is the version without the window). It handles DJI, GoPro and most other brands. Pick the sample clip, pick the broken file, and run. If the file that comes out won't open, run it once more, that happens. How you know it worked: a new MP4 appears, and it opens in a player.
Check the whole file, not just the start. The length should match what you shot. Scrub to five or six points along the video, especially near the end. At each one stop, play a few seconds, and check the picture moves smoothly and the lips match the speech. If the picture jumps or the sound drifts: the sample clip doesn't match closely enough. Find a closer match and run again. Don't switch programs.

Why it happened

A video file has two parts: the footage itself, which the camera writes the whole time, and a small map called moov, which tells a player how long the file is and where each frame sits. The camera writes the map last, only when the recording ends cleanly. If it shut off before, there is footage with no map, and the player refuses to open it.

What won't help

Renaming the file or changing the extension.
Converters, players that “repair on the fly”, and ffmpeg commands like -c copy or -movflags faststart. All of them need an existing map to read the file at all. They can move a map, not build one.

Short answers

Can ffmpeg fix it? Not when the map was never written. ffmpeg needs it to read the file. You need a program that builds a new map from a sample clip, such as untrunc.
The file is the right size and still won't open? Then the recording was cut off and the footage is inside. Go back to the steps above.
I have no technical background. Can I do this myself? Yes. The program works like any other: open it, pick two files, press a button. Nothing to type. What needs attention is the size check at the start and the video check at the end.

If you're stuck

If the file is big, if the second run also came out jittery, or you just don't have the head for this right now, send me a link to the file and to a healthy clip from the same camera. I first check whether the footage is actually in the file and tell you where you stand. That check is free. If there's something to recover and you want to go ahead, you get a price for the file. You pay, and then the work starts. And if I couldn't recover it, you get your money back, all of it or part of it, depending on the result.

Prefer email? avihaiteram@gmail.com

Who I am

Avihai Teram adjusting a camera on a tripod, a softbox behind him

Avihai Teram, videographer and video editor. I shoot on a Sony FX3 and work with camera files like these every day, so I know how a camera writes them and what breaks when it shuts off mid-recording, and I have brought files like these back from Sony and DJI cameras. Send me a file that won't open: the first check is always free, and if I couldn't recover it, you get your money back. You can also find me on Instagram: @avihai.teram.

Got “moov atom not found”? The video is probably not lost