[Digikam-users] How does digiKam do raw conversions for the slide shows ?

Milan Knížek knizek.confy at volny.cz
Wed Dec 23 18:03:27 GMT 2009

Linuxguy123 píše v St 23. 12. 2009 v 10:25 -0700:
> > Yes, it use JPEG preview. Fast and usefull...
> Are you serious/ sure this is the case ?  I always thought the preview
> jpegs were thumbnails.  I displayed the slideshow images on a 52" LCD TV
> at 1920x1080.  There was no way they were thumbnails.

JPEG preview may not be the same as JPEG thumbnail in general meaning.

E.g. Canon EOS 5D MII stores a small resolution JPEG, full resolution
JPEG and raw data in the CR2 files. The full resolution JPEG is kind of
equal to the JPEG that camera produces (if raw is not used), but
possibly with lower JPEG quality settings.


$ exiv2 -pp image.cr2
Preview 1: image/jpeg, 160x120 pixels, 11197 bytes
Preview 2: image/jpeg, 5616x3744 pixels, 1127852 bytes

to find out and

$ exiv2 -ep1,2 image.cr2

to actually extract the first and the second preview JPEG at the same
time. (This is not conversion from RAW!)

Exiftool may do the same job, read the man page...


Milan Knizek
knizek (dot) confy (at) volny (dot) cz
http://www.milan-knizek.net - About linux and photography (Czech
language only)

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