[Kde-imaging] Exif data

[Neil Winchurst]

Caulier Gilles wrote:
> Le Mardi 26 Septembre 2006 19:47, Neil Winchurst a écrit :
>   
>> Caulier Gilles wrote:
>>     
>>> Le Mardi 26 Septembre 2006 19:02, Neil Winchurst a écrit :
>>>       
>>>> Hi there,
>>>>
>>>> in a recent email this appeared.
>>>>
>>>>
>>>> Second points, is about metadata an pictures format : not all file
>>>> formats support metadata ! Exif (the most important format used in
>>>> photography) is supported by TIFF, JPEG, and PNG only, but not by TGA,
>>>> BMP, JPEG2000, EXR, GIMP, etc.
>>>>
>>>> Well when I change my photo files in Digikam from JPG to PNG I lose all
>>>> the exif data. If I leave the files as JPG then the exif data is kept.
>>>> So why don't my png files keep the data as mentioned above?
>>>>         
>>> witch digikam release you use ?
>>>
>>> Gilles
>>>       
>> Version 0.8.0.
>>
>>     
>
> digiKam 0.8.x use libkexif/libexif to manage metadata. These library are very 
> limited (to manage only JPEG files) and are now obsolete.
>
> In current timplementation of digiKam (0.9.0-beta2), we using Exiv2 library 
> instead. This one can drive JPEG, TIFF, PNG and RAW files formats to extract 
> EXIF, Makernotes, GPS, and IPTC metadata.
>
> Actually, Exiv2 can only write meatadat in JPEG, but for the next release, 
> PNG, and TIFF (and certainly RAW files) will be availabale in write access.
>
> I'm sure about that : i'm also a developper from Exiv2 project. I will 
> implemente the writting access to PNG files.
>
> In digiKam 0.9.0, if you convert a JPEG file to a PNG file, you will see the 
> Exif, Makernote, GPS, and IPTC metadata on the right side bar like you can 
> see in these screenshots :
>
> http://digikam3rdparty.free.fr/Screenshots/PNGsupportindigiKam1.png
> http://digikam3rdparty.free.fr/Screenshots/PNGsupportindigiKam2.png
> http://digikam3rdparty.free.fr/Screenshots/PNGsupportindigiKam3.png
> http://digikam3rdparty.free.fr/Screenshots/PNGsupportindigiKam4.png
>
> Also, in digikam camera interface, there is a new option to convert on the fly  
> all JPEG image to PNG without lost metadata during downloading.
>
> In fact, PNG support Exif, IPTC, and XMP to store metadata informations like a 
> byte array in a text chunk. This way is used by ImageMagick/GraphicsMagick 
> and Exiftools programs ! Try these command line for example :
>
> #convert foo.jpg foo.png
> #convert foo.png foo2.jpg
>
> If foo.jpg has Exif and iptc metadata, foo2.jpg will has too !
>
> Note : in the future, we have planed to add XMP support into Exiv2 library. 
> Like this all major metadata used in photography will be supported in digiKam 
> and kipi-plugins.
>
> To resume : if you wantto see you Exif data from png file, try digikam 
> 0.9.0-beta2 (http://www.digikam.org/?q=download)
>
> Gilles Caulier
>
>   
Thanks for all that. I will stay with version 0.8.0 until version 9.0 
final is ready. I will not risk the beta versions. Apart from the Exif 
problem my current version is working well. Also I have seen all the 
emails about problems with the beta version!!

Will the stable version 9.0 be ready soon?

Neil Winchurst



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