OBS crashed. Find out what is still in the file.
Drop the recording in below. Your browser reads its structure and tells you which container OBS wrote, how much footage is still readable, why it will not open, and the exact command that fixes it. The file stays on your machine.
Drop the recording that will not open
MKV, MP4, MOV, TS or FLV — any size, including a 60 GB stream.
Nothing is uploaded
The check runs entirely in this tab. Your browser reads a few hundred kilobytes of headers from the start and end of the file and never sends any of it anywhere — you can watch the network tab, or turn off your Wi-Fi and run it again.
What you will get back
- Which container OBS actually wrote, and whether it writes its index as it goes or only at the end.
- How many hours and minutes of footage are still readable, measured from the timestamps inside your file — not estimated from its size.
- The exact command that turns it back into a file you can play, and what that command will and will not recover.
What a crash costs you, by recording format
The difference is not luck. It is whether the container writes its index continuously or saves it for the moment you press Stop.
| Format | A crash costs you | Why | Fix |
|---|---|---|---|
| MPEG transport stream .ts | One 188-byte packet | None at all. There is no index and no duration — the format assumes a receiver that tuned in partway and will never see the end. | ffmpeg -i broken.ts -c copy fixed.mp4 |
| Fragmented MP4 .mp4 | One fragment | Many small indexes instead of one big one. Each fragment carries a moof header describing only the frames that follow it, written continuously as the recording runs. | ffmpeg -i broken.mp4 -c copy fixed.mp4 |
| Matroska .mkv | Under a second | No single index is required. Media is written as self-contained clusters as it arrives; the seek index (Cues) and the duration are added at the end as a convenience. | ffmpeg -i broken.mkv -c copy fixed.mp4 |
| Flash Video .flv | One tag | A tag-by-tag stream with an optional metadata block at the front. The metadata is written first, so its duration is a placeholder that a crash leaves wrong. | ffmpeg -i broken.flv -c copy fixed.mp4 |
| MP4 .mp4 | The whole recording | One index (the moov box) describing every frame in the file, written in a single pass when you press Stop Recording. | untrunc -s reference.mp4 broken.mp4 |
| QuickTime MOV .mov | The whole recording | A single moov index written when recording stops. MP4 inherited this design from MOV. | untrunc -s reference.mov broken.mov |
Read the full breakdown for MPEG transport stream, Fragmented MP4, Matroska, Flash Video, MP4 and QuickTime MOV.
Your file never moves
The probe reads box and element headers with byte-range reads. A 60 GB stream costs a few hundred kilobytes to check, and none of it leaves the tab.
Commands, not marketing
Every result carries the actual command, and what it will not recover. A remux is honest about being a remux; a rebuild is honest about needing a reference file.
The real cause is the single copy
Container choice decides how much you lose. Where the bytes live decides whether losing them matters at all.
Common questions
- OBS crashed while recording. Is my video gone?
- Almost certainly not. In every container except MP4 and MOV, everything written before the crash is already complete on disk and a single remux command gives it back. In MP4 and MOV the video and audio are also still there — only the index that describes them is missing, which is why the file will not open. Check the file before you assume anything is lost, and do not record over it.
- Why will my OBS MP4 not open after a crash?
- MP4 keeps one index, called the moov box, that describes every frame in the file. OBS writes it in a single pass when you press Stop Recording. If OBS never reaches that step, the file holds hours of video that nothing can locate. ffmpeg reports this as 'moov atom not found'.
- Does this tool upload my recording?
- No. The check runs in your browser. It reads a few hundred kilobytes of headers from the start and the end of the file and never transmits any of it. You can disconnect from the network and run it again to confirm.
- How long does it take on a 60 GB file?
- The same time as on a 60 MB file. The probe seeks directly to the structures it needs instead of reading the recording, so size makes no difference.
- How do I stop this from happening again?
- Record to a container that writes as it goes — MKV or fragmented MP4 — and keep a copy somewhere other than the machine that is recording. WeaverClip does the second part: it uploads each fragmented segment while you are still recording and verifies the byte count and MD5 of every segment before anything is removed from your disk.
The fix that outlasts the container choice
A recording is safe once it exists somewhere other than the machine recording it.
WeaverClip records in short fragmented segments and uploads each one to your private vault while you are still live. Every segment is checked by byte count and MD5 before anything is removed from your disk, so a crash costs you the segment in flight and nothing behind it. Free holds 10 GB and keeps it 30 days, with no card.
More: 24-hour streams without filling your disk · Import a recording you already have · Pricing