[OT] jpeg corruption

["Paul Robinson" <ukcueman@xxxxxxxxxxx>]

I've not been on list for a while, and I just got married (and yes,
those two things are related!)

Anyway, at the wedding, I had somebody grabbing digital photos from people
on the day using a laptop and a card reader. One
particularly important set of 350 photos got corrupted by pulling the card
out of the reader while it was busy. I managed to pull
the files off the card using a file recovery utility, but every 16th bit of
every file has been set to zero.

I'm using a card reader different from the one that was used on the day,
and using windows or linux to do the extraction using the
card reader, I get identical results.

I'm now learning about the gory details of the jpeg file format and
compression/decompression to see if there's any way I can
recover some of it. By comparison with a previous set of photos from the
same camera, I've managed to recover the headers on almost
all the corrupted photos. It's the raw graphic stream that's the problem.

The jpeg standard allows for reset markers to be placed into the graphics
stream to help recover from corruption, but this
particular camera doesn't use these.

Does anybody know of any way or any software designed to make a best guess
as to the content of the picture in this sort of
situation? With 15/16ths of every picture there, it might be possible to do
something sensible. Thought I'd ask before I try and do
it myself.

Thanks!
Paul