Can I find out partially destroyed video from hard disk?

[mike23]

When I save a video file on my hard disk then this video file is physically stored in multiple (thousands) of hard disk sectors. For simplicity lets say on sectors #200000 ..... #210000

Now lets assume I delete this file
a) by just deleting the FAT/NTFS file table entry
and
b) sectors #200000 ... #205000 are overwritten
by other files or by one of the true delete tools.

So at that moment still 50000 sectors with the original video file source exists.

Can users still find out the content of this video file?
Ok, obviously the first half (.e.g the first 20 minutes) are really destroyed. But what about the second 20 minutes of the video file:

Can they by recreated (without having acces to the first part)?

Does it matter what kind of video format it was:

*.avi
*.mp4
*.mkv

Mike

[StainlessS]

File recovery, TestDisk and PhotoRec:- http://www.cgsecurity.org/wiki/TestDisk
EDIT: For above, read all docs, it is not idiot proof, but can make an image of a disk and you can try to recover using
the image only. (NO GUI). EDIT: Secondary drive required for writing recovered files.
EDIT: Massive list of file formats recovered by Photorec (not just photos):-http://www.cgsecurity.org/wiki/File_Formats_Recovered_By_PhotoRec


DoD secure file deletion:- https://www.google.com/?gfe_rd=cr&ei=tAFqVuTzKdLS8AfknKK4BQ&gws_rd=ssl,cr&fg=1#q=dod+secure+file+delete


EDIT: I assume your goal is to securely delete something. Wiping FAT directory entry is not terribly secure (fairly easily recovered),
dont know how difficult it would be to recover NTFS, but (I think), would probably not be a big deal either.
EDIT: So far as I remember, deleting a file on FAT only blanks the first character of the name (making name invisible and seem empty),
and also marks the clusters in the FAT as free, but the entry in the directory that gives the number of the first cluster is not wiped from
the directory entry (so you know where the deleted file starts, and if non fragmented then is recoverable [file length also not deleted in directory])

Blanking first half of the file would make it more difficult, but perhaps forensic recovery software could recover file to
some degree (depends upon container and codecs involved).
EDIT: DVD Mpeg2 could probably be recovered, has a special flag which tells where to start decoding from (every now and then in
stream, cannot occur elsewhere in stream to avoid mistakes). Also, flag assists in corruption recovery in un-reliable streams due
to eg marmalade on a DVD disk.

[Ghitulescu]

Nicely ask NSA, they surely have kept an image of your HDD.

[laserfan]

...Can users still find out the content of this video file?
Ok, obviously the first half (.e.g the first 20 minutes) are really destroyed. But what about the second 20 minutes of the video file:

Can they by recreated (without having acces to the first part)?
The most like answer is "yes, depending on who is trying and how committed they are to recovering it".

If you are looking for a secure erase tool, try PrivaZer.