[magick-users] Using identify for unique IDs

[Adam Goldberg]

how does this process multi-frame images or movies?  does it iterate
over every pixel in every frame?    maybe there is a more efficient
way to generate unique ids that will not change when exif data is
modified?

thanks again for your help,
adam




On Mon, May 5, 2008 at 1:31 AM,
<duc.sequere.aut.de.via.decede at imagemagick.org> wrote:
> > but it still takes a really long time
>
>  The signature is computed by iterating over every pixel in
>  the image.  ImageMagick Studio distributes the Wizard Toolkit
>  (http://wizards-toolkit.org/script/digest.php) which includes a digest
>  program that efficiently returns a signature as RDF:
>
>   <?xml version="1.0"?>
>   <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>            xmlns:digest="http://www.wizards-toolkit.org/digest/1.0/">
>     <rdf:Description rdf:about="image.png">
>       <digest:modify-date>2008-04-25T20:19:02-04:00</digest:modify-date>
>       <digest:create-date>2008-04-25T20:19:02-04:00</digest:create-date>
>       <digest:timestamp>2008-04-26T12:25:47-05:00</digest:timestamp>
>       <digest:hash>SHA256</digest:hash>
>       <digest:digest>78709afc0de69f51085675329dc44c8b475258c1e7fd29acea078347e641a020</digest:digest>
>     </rdf:Description>
>   </rdf:RDF>
>
>  However, as you suggested, it will return a different signature if the EXIF
>  data is changed.
>