Salvaging a Corrupted Quicktime File

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For some reason we’ve been snake bit during our last two attempts to use the AJA KiPro on location as a record device.   We’ve had corrupted Quicktime files on very long records.   On the previous project we were able to repair the file easily using Disk Repair but for yesterday’s shoot, the 40GB Apple ProRes LT file (42 minutes) simply would not come back.   Kept telling us that Quicktime, Premiere Pro, Prelude, and everything else I tried “could not recognize the format of the file.”   That generally happens when the file does not finish the recording correctly adding the necessary data for the applications to read the file.

Yesterday we were using the KiPro as our primary audio recording device for two of the four wireless mics.   We’ve done this in the past and it works quite well.    Of course the file that was damaged was THE most important file we needed with the primary 42 minutes of our shoot.   Without that audio, we would have to rely on the boom for all primary audio and we really didn’t want to do that.

So I turned to Twitter to ask for help salvaging at the very least the audio files and got two very good recommendations.  One was able to salvage the video and one both the video and Audio so I wanted to share.

Salvaged the entire file:  HD Video Repair Utility   This tool uses a reference file from the same camera to compare the corrupted file to.   So first you Choose the corrupted file and the Choose a Reference file.   Then you hit Scan and it does its magic.

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I think it’s the reference file idea that really allows this thing to work.   I did the free trial first because the KiPro and ProRes is not specifically mentioned on the page.   The free trial limits you to just half of your media running time. So in my case it salvaged a 27 minute file and I could see that everything was there exactly as it should be.  Video and 2 channels of audio.  Purchase is $29 Euro to repair 5 files.  As of right now that was just over $37 US.   HUGE sigh of relief for me for sure.   5 hours lost this morning in edit time is more than made up with the salvaging of this file.

Note on the tool, I did receive a warning on my Mac telling me that the software “might not be safe to run” because it was not from an “approved Apple developer.”   I clicked through anyway and I’m really glad I did.

UPDATE CAVEAT: The file WAS repaired but for whatever reason, we encountered audio sync drift.   So if I had required the entire 1 hour clip to be in perfect audio sync start to finish, that would have required me going into ProTools or other audio mixing program to re-time the audio.  But for my needs, I was simply cutting quick clips out of the scene.

Salvaged the Video: Digital Rebellion Pro Maintenance Tools  In this case the “Media Salvage Tool” was not able to help me get everything back because it doesn’t currently support the multi channel audio from the KiPro but when you purchase this, you get a whole toolkit full of maintenance and repair tools so it’s a good “swiss army knife” to have in your toolbox to help solve a a lot of common issues.

Thanks everyone for your suggestions and I hope this info is helpful to you all when you get into the same situation.

2 replies
  1. Sodo says:

    I used the Grau GmbH video repair program on some corrupted output from my Canon 5D Mark II. The file was actually corrupted within the camera. I fed the program the corrupted file and a good, reference file to base to fix off of. I was very psyched to see that the program fixed the read issue. But as you state, the a/v sync was off in the output file. I fixed the sync by experimenting with FFMPEG’s itsoffset, like so: ffmpeg -i INPUTFILE -itsoffset 0.75 -i INPUTFILE -map 0:0 -map 1:1 -acodec copy -vcodec copy OUTPUTFILE After doing this, the file was workable enough to use. Thanks very much for the help finding this great little program. Kudos to the Grau GmbH guys.


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