[Digikam-users] Comments in png files

[Paweł Marciniak]

Thank you Gilles for replying!

Gilles Caulier wrote:
> Exiv2 do not support yet PNG metadata for writting. Patch still uncomplete
> on my computer.
> [...]
> yes, Caption, date, rating, and tags are store in digiKam database.

I see. Is there a way (it may even involve some hacking) to retrieve the
captions from db and embed them in jpeg files? Otherwise it's A LOT of
rewriting for me :( 

>> When converting manually with convert, no error is raised, but when I try
>> to
>> view the converted image in digiKam, no metadata is shown at all. 
> 
> Exif and iptc ??? Impossible (:=))). All my photo collection are in PNG
> (taken originally from JPEG or RAW), and metadata still present of course.
> 
> Witch camera you use ? Can you send me a JPEG file taken with your camera
> to test. How are you converted your JPEG files to PNG ? Using Camera
> interface during download ?

Yes, there's nothing after opening the photo in digiKam (display(1),
however, sees exif metadata in the jpeg, but not iptc). I found out that
the digiKam console says:

8<-------------------------------------
Warning: IPTC dataset Iptc.Application2.Preview has invalid size 67904;
skipped.
Cannot load metadata using Exiv2  (Failed to decode IPTC metadata)
8<-------------------------------------

It looks like ImageMagick issue, but the png may be misformated as well. The
interesting thing is that ImageMagick doesn't complain during conversion,
and upgrading it to the latest version (6.3.6-7) didn't solve the problem.
I uploaded an example (both the orginal photo and convert(1) output) to
http://pandora.cs.put.poznan.pl/~pmarciniak/digikam/ photo name
marineland-021.{jpg,png} - feel free to inspect it. All my photos were
taken with Canon S2 IS and converted to png during download.

During downloading and commenting my photo collection I was using svn
version of digiKam, recently I reverted to binary package (0.9.3-beta1),
but I guess that should not be a problem, since it is still newer than my
last svn build.

I also uploaded to the mentioned location another example, marineland-001
{jpg,png}, where the jpeg's exif metadata is shown correctly by digiKam,
but not iptc, and the console says:

8<-------------------------------------
Warning: IPTC dataset Iptc.Application2.Preview has invalid size 67818;
skipped.
Warning: IPTC dataset Iptc.0x00ce.0x0056 has invalid size 10114; skipped.
Warning: IPTC dataset Iptc.Application2.Preview has invalid size 67818;
skipped.
Warning: IPTC dataset Iptc.0x00ce.0x0056 has invalid size 10114; skipped.
8<-------------------------------------

Pawel