[Digikam-devel] [Bug 262452] duplicate uniqueHash (image hash) in database, wrong thumb on images

[Elle Stone]

https://bugs.kde.org/show_bug.cgi?id=262452





--- Comment #2 from Elle Stone <l elle stone gmail com>  2011-01-08 00:03:42 ---
Hi Marcel,

Regarding, "This is a problem, known and solved (for the future). 1)
This happens usually with TIFF images without metadata."

In fact the affected images, tiffs output by UFRaw 0.16 and 0.17, have
a LOT of metadata, all the metadata that was in the raw file (.cr2).
If one were to use exiftool to add eg copyright information, keywords,
contact information, location, etc.to one's raw files (which I do, in
fact) there could be a whole lot of metadata in a raw file.

Suspecting that a wealth of metadata could be the problem, I used
exiftool to strip out all the metadata in the UFRaw-produced tiffs,
and when I added the stripped tiffs to the digikam database, the
stripped tiffs all had unique hashes and proper thumbs.

Is the future solved bug version of digikam available somewhere?

Elle Stone

On 1/7/11, Marcel Wiesweg <marcel.wiesweg at gmx.de> wrote:
> https://bugs.kde.org/show_bug.cgi?id=262452
>
>
> Marcel Wiesweg <marcel.wiesweg at gmx.de> changed:
>
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>              Status|UNCONFIRMED                 |RESOLVED
>          Resolution|                            |DUPLICATE
>
>
>
>
> --- Comment #1 from Marcel Wiesweg <marcel wiesweg gmx de>  2011-01-07
> 23:39:33 ---
> Thanks a lot for your research, indeed this is a problem, known and solved
> (for
> the future).
>
> 1) This happens usually with TIFF images without metadata. The header of
> such
> files contains several kilobytes of (pretty useless) line offsets. I have
> not
> seen a JPEG which is affected
>
> 2) Computing the hash over the whole file is a major performance problem -
> scanning would take much longer. The old hash covered 99.9% of cases, we'll
> see
> what the new algorithm brings.
>
> 3) Some other problems in context of renaming are probably unrelated
>
> *** This bug has been marked as a duplicate of bug 210353 ***
>
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