need help: how to re-create / repair AVI header?

[qba]

Dear forum-users,

Few months ago I copied from DV camcorder to HDD my film from my last trip. I planned to work on it, edit and record onto DVD. Bad luck, but during instability of my system, my file with this film started to show that its length is 0kb instead of 18GB). In some recovery programs it shows that file on disk still occupy 18GB but they can not recover it. I've already sent this hard disk to Ontrack - company that professionally recover files from disks in even worse conditions but they says that the avi file lost its header and because of this it is unrecoverable.

I found a Ph.D. in internet, which told me that I can fix it manually but of course there is need of knowing AVI header format.

Does anyone know program which can recreate or repair AVI header? Or can help with manually do this?

best regards
XyZoN

[ultimatebilly]

I would try to play the file with mplayer, maybe with the -idx switch, which generates a new index for the avi-file, because mplayer is able to play almost everything you throw at it.
You can get mplayer here (you have to use it with the command prompt): http://www.aziendeassociate.it/cd.asp?dir=/mplayer
But windows reports the file to be of 0KB in size, right?
Then I don't think you will be able to play it back...
I would think that the size would be reported correctly, even with a missing header, but I don't know.
I would also try to open the file in VirtualDub, which is also able to write a new header.
But to me it rather sounds like it is a file-system issue, you won't be able to solve that with media-players or converters.

[Sirber]

VirtualDub can do it.

[stephanV]

Losing a header should not make a file unrecoverable and it certainly shouldn't show up as 0 kb because of it. Basically i think you're screwed. The easiest way would be to copy-paste a header of a similar file with a hexeditor in front of this one.

EDIT: VirtualDUb CANNOT fix headers, it can only reconstruct an index. Opening an AVI-file without a header and having no knowledge of its content is impossible.

[qba]

VirtualDub said: "can't open, the file is empty"
mplayer unfortunatelly can't find sdl.dll to run.

ultimatebilly: it is not file system issue, Ontrack checked this in low level and says that the header of avi is missing.

stephanV: isn't file size stored in a file header? And if I tried to copy paste header of another file how to recognize which part of code is header?

[stephanV]

i was talking about the AVIheader, not a file-header (if such a thing even exists). empty file error means the file is 0 bytes. theres not a lot a program can do with that little data :)

sorry, nothing you can do.

[qba]

That file indicate 0 bytes BUT some recovery programs show that size on the disc is 18GB. That means the header is overwritted and there is lack of some information but other data exist. (it is similiary to operation of delete file - only some informations changed - phisical data still exist but is not marked as "can not be overwritten")

[stephanV]

well, you cant fix it with a video editing tool... you need some file system tool for this. this has nothing to to do with giving a file an AVI-header.

[qba]

Are You sure? Does ahead avi header exist file header? Does avi header contain information about file or only about avi structure? Almost every kind lack of information can be added manually if You know where and how do it.
Where I can find something more about avi structure? Maybe copy/paste from another similary file can work for this?

[stephanV]

dude, your file system says this is a file with 0 bytes. If you open it in a hex-editor you get nothing. paste a avi-header in it nad youll have a file with only a AVI-header, nothing more. the aviheader only contains stuff like frame rate, frame size and amount of frames and things like that. its not magically gonna turn into a 18GB file after pasting it in.

basically, what those people told you was crap.

[Sirber]

So this is a file system issue. Could you please rewrite the subject of this post?

When it's about file system corruption, you have 80% chances your file is lost. The more you wait, the more it's unrecoverable. Even if you succeed to recover a file, you have chances it's corrupted and unplayable.

[qba]

This is on separate, non system disc which is non-used since that. Not used to write on it. I hope that chances are not going down, beside this to overwrite and waste 18GB even Win need a time.

Thank You for all your ideas and help. Now i'm going to file structure forum. I guess (and hope) that I come back here with only damaged avi header;)

One more question. What are the chances to repair corrupted avi (I mean it will be already 18GB one)?

[Sirber]

Lots of chances you have not just the headers corrupted, but the frames too. Corruption doesn't seek for headers ;) For 18GB, you've got almost no chances to get the file uncorrupted.

[stephanV]

well since its DV, a corruption in a frame shouldnt be too destructive. the real question is how many frames are corrupted. :)

[qba]

There is no problem if I loose even 1GB (its only 4.5 minuts out of 90;)) but if this file will be scratched at few places does it will be still recoverable?

[Sirber]

Depends on what you want, for me, if the file is not 100% there it's a total loss. Better have it fully, or not.

[hpn]

DV footage is easy to recover even if most of the file is lost (overwritten with zeros or other data). You know that when you rewind or forward a tape in your DV camcorder, you can instanty play it from any random point with frame-accurate seekability. You don't need the camcorder to go to the end or the begging of the tape to read headers or indexes, do you? It's not like the MPEG-4 files (XviD, etc) where you need headers and indexes in order to play a file correctly). So just install your corrupted HD and a second HD (make it your bootable one) where you'll copy the recovered file to (both disks on the same PC), then install any file unerazing tool (on the second HD!) and uneraze the lost file to your second HD (or what's left of the file). Now you have a 18GB file again, probably corrupted at places, but you could try to play it. If it doesn't play just add a few seconds of any other DV file before the correpted file, by simply combining both files (you could use google to find some free tool for it) and try to play it. If it plays, you could upload it back to your camera (first load an emply DV cassette :) ) via your Fire Wire interface in case your DV camcorder supports digital input (most do). Then you should be able to play the whole movie on your TV (only missing the scenes from the currepted parts of the file), and download the same footage back to your HD as a perfectly valid DV stream.

[qba]

The problem is that I've tried ca. 10-15 recovery softwares and no one can be able to recover it:( Maybe I'm not precize - most of them culd and recovered this file with... 0 bytes long. Only one - Active @ Undelete show me that on the HDD this file still occupied 18GB. But even this software couldn't recover it. Some strange thing that i found that file marked with atributes "AI". "A" is obvious but what does "I" mean (or AI it is Artifical Intelligence?;))

[Sirber]

Incomplete? ;)