[Digikam-users] How does digikam calculate the uniqueHash ?

Marcel Wiesweg marcel.wiesweg at gmx.de
Sat Apr 10 15:53:53 BST 2010

> I then could correctly calculate the uniqueHash for jpeg images, but
> not for raw images.
> raw images are usually based on the TIFF file format. Exif data are
> afaik TIFF entries. Therefore, TIFF files do (unlike JPEG) not have a
> separate Exif section, but have Exif tags (which are in fact TIFF
> tags) interwoven with the hole file.
> How exactly is the uniqueHash calculated for these files?

We currently just rely on exiv2 to give us the data. For TIFF, I guess this 
means exiv2 will take the Exif tags, encode them in a section as it would be 
suitable for writing in a JPEG, and return this data. It's not a perfect 
solution but no other is currently available.

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