Bug#127228: ITP: jhead - EXIF header extractor for digital camera images
Package: wnpp
Severity: wishlist
Package name : jhead
Upstream Author: Matthias Wandel
URL: http://www.sentex.net/~mwandel/jhead/
License: Public Domain
This blurb cut/pasted from the above URL:
The files coming out of a pretty much all Digital cameras are in the
Exif flavour of Jpeg files. Exif files are for the most part Jpeg files,
but start with a different header block, and contain additional data
sections with camera settings, as well as a preview thumbnail picture as
part of the Exif header. Most editing / viewing software just skips past
the Exif header and ignores it outright, so you normally don't notice
its even there.
Because I am interested in photography, I am always curious just exactly
what settings my fully automatic digital camera actually did end up
using. There's a few programs out there that can parse some of these
headers, but I couldn'd find one that I could compile to an executable,
and none that actually figured out what the camera settings were from
the various confusing ways in which the fields can be expressed. Parsing
the data of interest out of an Exif header is not straightforward. There
is a large number of ways that simple data such as shutter speed or
aperture setting can be expressed in inside of an Exif header. It can be
an integer of various forms, or a fraction or floating point, which must
subsequently be raised to a power to get the true value. Then it can be
stored big-endian or little endian, and there are different fields for
expressing the same values! It sounds like complete eveolutionary
anarchy, but I think its just a comitee designed spec. With all its
complexity, interestingly enough, plain text ASCII would both be smaller
in size and easier to parse! So I wrote this command line driven program
to parse through the little file system in the Exif headers and extract
the stuff I really care about
--
- Dave Baker : dave@dsb3.com : dave@devbrain.com : http://dsb3.com/ -
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