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MJPEG AVI file corrupted - how to repair?

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Paul Randall
MJPEG AVI file corrupted - how to repair?
on Nov 3, 2014 at 12:48:27 am

Hi all,
I have a situation where during a live recording via Media Express the PC lost power so I was left with a non completed AVI Motion-JPEG file (1080i50 - 290GB file size). I can see and copy the file but cannot play it. Can anybody please tell me what utility or tool should I use to fix the file?

I have tried so far:
VLC: Does not even think there is a problem it and just won't play it so I cannot use the fix avi feature.
VirtualDubMod: Also does the same, opens the file but cannot play it or resave it.
Remo Repair Avi: As the file size is 290GB the program cannot fix it.

What happened:

The UPS tripped out due to a large voltage spike on the main power lines outside the building causing the video switcher (and all recorders to power off). It happened during a live recording at a venue (so recapture is impossible) and to make things worse all the ISO recording from the cameras were also lost/damaged so a real disaster. We also lost various lighting and sound equipment with the voltage spike during the show including the projectors which when black and locked up.

Thanks Paul


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James Brooks
Re: MJPEG AVI file corrupted - how to repair?
on Nov 3, 2014 at 2:12:02 am

Hi Paul

It is possible to write a program to search out the MJPG frames and save them off to another container, but I don't know of an 'off the shelf tool' that will do that.

Cheers, James



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Chad Pearson
Re: MJPEG AVI file corrupted - how to repair?
on Nov 3, 2014 at 8:15:00 pm

I vaguely remember using a program called VirtualDub that could parse through a video file and extract out the good frames. It's also a good transcoder software too.


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Paul Randall
Re: MJPEG AVI file corrupted - how to repair?
on Nov 3, 2014 at 10:08:44 pm

I did try VirtualDubMod but it did not work. I did a "Create sparse AVI" file then did a "Expand sparse AVI" file but the Expand sparse AVI was about 15GB smaller but still did not play. I am not sure if what I did was correct so any advise on using the program is appreciated

FYI when I try and play the file from Media Express the display says "Media Offline"


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Paul Randall
Re: MJPEG AVI file corrupted - how to repair?
on Nov 3, 2014 at 10:09:34 pm

Have you got any ideas on where I can find such a program?


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Russ Froze
Re: MJPEG AVI file corrupted - how to repair?
on Nov 13, 2014 at 10:20:12 am

Hello,
Have you tried Avidemux? Or what does Davinci Resolve have to say about it?
http://avidemux.sourceforge.net/
Let me know if this resolves your problem or not. For I am keenly interested for but for the grace of God, there go I.
Russ Froze


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Paul Randall
Re: MJPEG AVI file corrupted - how to repair?
on Nov 13, 2014 at 8:47:57 pm

Avidemux says "Attempt to open video.avi failed!"

DaVinci Resolve lite 11.1.1 - I have not used this software before. I tried to add some different MP4 and AVI video files to the media bin but it would not take them. I am not sure if I am doing this correctly - any suggestions?


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Russ Froze
Re: MJPEG AVI file corrupted - how to repair?
on Nov 13, 2014 at 11:29:23 pm

Yea Da Vinci is a real pain to set up and for some reason my instal has quit working. I doubt it would open the file anyway but it is a close cousin of Media Express so I thought maybe. Anyway try this
http://sourceforge.net/projects/divfixpp/files/DivFix%2B%2B/v0.34/

Warning do not click on anything after you click on the DivFix++_v0.34-Win64.zip link. It will take you to another page instantly and confuse you into installing something else. If using Chrome wait for the download the open in download folder. After that you can handle the zip file and extract tit where you like. Do make a copy of the original file(s) and work with the copies not the original.

Let me know of success or failure.
Russ froze


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Paul Randall
Re: MJPEG AVI file corrupted - how to repair?
on Nov 14, 2014 at 8:40:09 am

OK DivFix++ gave a lot of errors like:

Processing file : Rage P2.avi
Four CC is : MJPG
Warning: Frame size is too big! Dropped
Error detected at byte: 9870
Skipped 1228240 bytes.
Warning: Frame size is too big! Dropped
Error detected at byte: 1238118
Skipped 1228170 bytes.
...

So did not work.

I did try Digital Video Repair V2.2.4 from http://www.risingreasearch.com

It did actually go right through but at the end WMP could not play it but VLC sort of did after "Fixing AVI index file" but only played about 40 min but should have been about 5 hours long. So not sure what to do now as Adobe Premiere still cannot use the "fixed" file anyway.


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Russ Froze
Re: MJPEG AVI file corrupted - how to repair?
on Nov 14, 2014 at 3:04:36 pm

Now use VLC or avisynth to render it out, choose an appropriate codec for the job. Again I know nothing about the camera or codec used so that decision will be up to you. I know there is a few hours of the file missing but for now have a look at what's there and find a codec combination the NLE can work with it.

Now back to DivFix, did you try strip index?
Russ Froze


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Paul Randall
Re: MJPEG AVI file corrupted - how to repair?
on Nov 15, 2014 at 2:39:50 am

Tried DivFix++ but got the following error:

Striping index at file: Rage P2.avi
Error: File cannot truncate at 999931730
Error occurred at striping index

VLC did export out the 44 minutes as a MP4 but as big chunks of video was missing it is not much good. The 44 minutes is a bit like a highlights video from the 5 1/2 hours - with the audio going in an out of sync.


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Russ Froze
Re: MJPEG AVI file corrupted - how to repair?
on Nov 15, 2014 at 4:32:47 am
Last Edited By Russ Froze on Nov 15, 2014 at 4:38:35 am

Yeah well that's what I feared. I don't hold out a lot of faith for retrieving a great deal more of the file. It's probably flung all over the drive with no index file indicating where things are and what belongs where. This is way beyond my field, perhaps there is a magic bullet out there but I know not where it is. If you find it let me know

The only hope is to find someone who can open it in a hex editor, but I don't know. It's a very large file and even larger when decompressed. There are data retrievals services so it depends on any lawsuits that might arise from failure to provide promised services or lack of payment coming to you. This may become a legal issue for you should anyone put forth claims against you or your company. In that case I suggest see a lawyer.

It comes down to what is it worth, data retrieval is not inexpensive and there are no guarantees of what you'll get. Chances are there will be much lost and what is retrieved may well be much like an omelette. Yes the whole egg is there but. On the other hand you might get lucky, like I said it depends on what it's worth.

Where to look for help is with the coders in the usual online places such as http://sourceforge.net/ under the Audio/ Video section but be carefull if you stray off the path and visit only with an installation that you can afford to loose. If you don't have an old beater machine, scavenge a drive from somewhere and use it to boot your system to visit that part of the net. They are sneaky after all thats what they do, they can't help it.

Now this won't help with the currents issue of the brocken file. Merely something for consideration. I have been recording on PC since firewire came out so far so good. I have lost power during a shoot but what saved my bacon is that I only shoot image sequences or use capture software that breaks files into a segments of 600mb. I have added uninterruptible power into the mix so that in the event of power fluctuation there is enough power in reserve to shut down the system.
Russ Froze


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Paul Randall
Re: MJPEG AVI file corrupted - how to repair?
on Nov 18, 2014 at 2:44:08 am

I have worked out a work around - not perfect but it only just works. What I did was use VSO Media Player1 as it was the only program I found that actually played the video. Even VLC did not even attempt the play the video. I then just re-encoded by playing it on my laptop then capturing it via my Decklink card using a HDMI to HD-SDI converter. I had no control of the playback - could not fast forward or rewind only play. I did end up capturing just over 5 hours of video so at least I have something. The video is a bit jerky in places and few areas where the video goes slow but that is better than nothing - I do have a separate audio recording so I just need to do a lot of re-syncing.

Thank you Russ for your help and offering plenty of suggestions.

regards

Paul


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