Repairs truncated videos.

Don't get your hopes up, some videos can't be repaired.

Step 1: upload the broken video

Step 2: upload a short working video

Step 3: your email (optional)

You will be notified once the video is fixed. Or untrunc fails :(

Step 4:

Cross your fingers and push this button.


Video and audio streams are divided in packets. A video player needs information about the codecs used and an index containing position and length for every packet. Camera software writes this data at the end of the recording, and if the sofware crashes or power is lost before this crucial step, the information will be missing.

Untrunc recover the information about the codecs using another short, working video taken from the same camera and with the same camera configuration. The index is rebuild guessing where each packet starts and ends.

I wrote this code after the video of my wedding got truncated when the camera died. I guessed I wasn't the only unlucky one, hence the source code is available on GitHub.

You can write me at: ponchio@gmail.com


What do you do with the videos?

The videos will be deleted after a week if untrunc managed to recover the damaged video. Failed video won't be immediately removed, I might be able to fix them manually, but will require more time. Sooner or later they might be removed as I will run out of space. You can always delete your videos.

Why do I need to upload a second video?

The truncated video lacks vital information about the codecs, I can just recover that information from a working video, provided is taken using the same camera and the same setting.

Is this free?

Yes. It will stay free. The source code has been available for 10 years, but a lot of people have troubles compiling it, and it's complicated for me to provide executables. It will be easier for me to provide a service. If you really feel like you have to contribute, a link for donating beer money is at the end of the page where you can download your fixed video.

Untrunc failed! Why?

Different cameras use different software which adopts different strategies to write the video file, and can fail in many different ways. It's complicated. Moreover some codecs are easy to locate, other are quite hard. Sometimes the truncated files are empty and really nothing can be done.

How do I get my fixed file without an email?

Once finished uploading you will be redirected to a download page with an unique URL. It might take some time (hours?) for the video to be fixed. In the meanwhile bookmark this URL. The download page will keep track of the status. If cookies are allowed, the videos will be listed at the top of untrunc.it page.