Corrupt MP4 Files? Fix Them for Free with this Great Trick

After recently playing around with a time-lapse app on my Android device, I discovered that setting a long capture period resulted in a very large, corrupted file. Was it possible to repair it, and if so, how?

The Corrupted File

Sitting at 1.29 GB, the newly created file refused to play back in any of the apps on my phone. The first thing, then, was to quickly transfer it via USB to my PC. Once this was done, it was time to try the old fallback, VLC Player. This incredibly versatile app can play video files that are only partially downloaded, as well as all of the other amazing features it has, so it seemed a good bet.


Unfortunately, even the free and open source VLC Player was unable to show me what had been captured in the time-lapse video. I had to find another option.

Using a Video Repair App

Apps that fix dodgy videos are not in wide supply. They don’t come pre-installed on Windows or other operating systems, they’re (surprisingly) not included with video editing tools; in short, they’re rare. As such, we tend to discard videos that don’t work.

In the case of my time-lapse project, this wasn’t a solution. I needed to see what had been captured, and so a video repair tool was really the only option. Eventually, I found a solution that might work – Video Repair from Grau GmbH. While a premium option is available, I first decided to try the corrupted file with the demo version. This has a cut-off point, which means that only the first 50% is repaired. Given the size of the file, however, this was worth the effort — after all, I didn’t want to pay for an app that would fail to repair the video.

Repairing the Video

With the app loaded up, I needed to have both the corrupted video and a similar file, recorded with the same camera and app (and of the same subject) as a reference, also saved to my computer. Once downloaded, Video Repair must be unzipped (natively, or with a tool like 7zip), rather than installed, and the unpackaged gs.exe file run to open the app.


After selecting the language, and taking note of the 50% limit which is clearly outlined, I browsed for my corrupted video file (MP4 and MOV files are compatible with this app) in the Choose movie… box, along with the reference file in Choose reference movie…. The movie is repaired by clicking Scan.

If successful, Video Repair will provide a list of fixes it employed to make the movie watchable. But if no list of fixes is provided, Video Repair cannot fix your video.

One Fixable Video, One Expensive App

Say, for example, that you have just one corrupt video you want to repair. Video Repair would be the sensible choice now you’ve been introduced, but there’s a problem. It’s expensive. To purchase the app would set you back €29 (around $33) and this only provides FIVE repair jobs. For an unlimited license, the price is €99 ($114). Now, if you find that you regularly have videos that turn out corrupt, this might be an option; however, finding the underlining causes of your corrupt clips might be a better strategy.

So, what do you do to repair the entire video? Well, you can pay the fee and buy the full version, or you can use some totally legal trickery to get the video restored in its entirety…

Double Up and Repair

As demonstrated by YouTube user R3DLIN3S, it’s possible to trick Video Repair into repairing the entire video. The idea is simple: we make a video file that is twice as long, and still convert just 50% of it. Because we doubled the video length, the file that is converted is our entire original file.

But how do we do this?


Begin by dropping the corrupt file into a new, dedicated folder (we called ours “Corrupt File”) and copy it so that you have two identical files — understand that this may take a while for larger files. Now, you should rename them; it’s best to give them sequential names, like VID1 and VID2.


Next, open the command prompt in the Corrupt File directory (hold SHIFT > right-click > Open command window here) and enter the following:

copy/b VID1.mp4+VID2.mp4

This takes a while, but will stitch the two files together into a single MP4, in place of the first file. So in effect, VID1.mp4 is now VID1.mp4 and VID2.mp4.


You can confirm this by checking the file size of VID1.mp4 — if it is now twice as long as it was previously, you’re ready to use the repair tool, as demonstrated above.

Buy it if You Like It!

Although we’ve demonstrated how to fix a one-off corrupt MP4 file, if you like the app and believe it will work for you in the future, then we would encourage you to spend money on Video Repair. But for a one-off fix, our legal cheat should do the trick.

So, a straightforward, quick and easy way to repair a corrupt or broken MP4 file. Does it work for you? Or do you have a better alternative? Tell us in the comments!

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