[Digikam-devel] First proposal for IPTC interface

[Renchi Raju]

On Mon, 25 Jul 2005, Heiner Lamprecht wrote:
> On Monday 25 July 2005 18:44, Renchi Raju wrote:
>>
>> has there been any change in the issues which i raised my concern
>> about:
>> * internationalization support
> Well, this is quite easy to solve.  I already discussed with Andreas
> to add gettext support.

that's good to know. if i understand you correctly, the process hasn't 
started yet. this might take some time as the translators have to be found 
as well

>> * wide spread availability.

i was talking about the availability of exiv2. as far as i know, none of 
the major distributions package exiv2 currently and adding a dependency 
which requires user to fetch sources and compile would be a big no-no.

>> * iptc becoming an obsolete format with a transition to xmp.
>
> ;-)  XMP is not wide spread, too.  It might become a future
> standard, but how many applications make use of it today?

none on the linux side, but quite a few in the windows world and the 
number is increasing steadily. otoh, the number of applications supporting 
iptc on the linux side is rather few as well.

>> additionally iptc is available only for JPEG and TIFF file
>> formats and not for PNG, which is widely used by many of the
>> users.
>
> ACK
>
>> the other issue is IPTC not supporting hierarchical tags
>> (as you pointed out) which prevents it becoming the primary image
>> metadata format.
>
> But in opposite to EXIF it supports different types of meta data,
> like location, ...
> In addition, I want to store all metadata within the imagefile and
> don't want to use any external file.  Having the db file is okay as
> an index for faster searching and filtering.  But in the end, the
> primary has to be the image.  I don't like the idea to be bound to
> any specific application.

i don't disagree with you. in fact the proposal that i made earlier was to 
use XMP as the primary image metadata container. it supports all of what 
iptc can do and then some. in addition it has support for PNG files, which 
is critical for us.

the plan was to extend libkexif to support IPTC, XMP in addition to EXIF. 
the EXIF/IPTC was to be treated as read-only formats (from where the 
metadata is read in). but new data written out to files is to be done in 
the XMP part of the image. there is at least one  other kde developer who 
is also interested in this type of library. the iptc read support is not 
difficult and i have a partial implementation of a library which does 
that. XMP again is not difficult, if we use qt's dom infrastructure.

just to summarize:
the different components of the libkexif library will be:
EXIF (use libexif)
IPTC (native implentation)
XMP  (native implementation or Adobe's opensource SDK)

renchi