[Digikam-users] Image Metadata extraction : implementation progress...

[Gilles Caulier]

Hi all digiKam users/team,

Like you have seen last week, I have started a new implementation of metadata 
viewer using libExiv2 instead the current Exif viewer using libkexif.

A fresh screenshot can be seen here :

http://digikam3rdparty.free.fr/Screenshots/digikam0.9.0-alpha6.png

After any days of indeep testing, the implementation is more mature. Like you 
can see in this screenshot, we have :

- A standard Exif metatada viewer.
- An Exif  Maker Notes viewer 
- An IPTC metadata viewer.
- Support of CRW metadata (thanks exiv2)
- Support of Raw profiles embedded (Exif/IPTC) in PNG files built by 
ImageMagick during JPEG -> PNG conversion.
- Each sidebar tab can be filtered to "Simple" (user friendly: the more 
important for photograph) and to "Full" (all metadata).
- All metadata groups are more visible than old Exif viewer.

The implementation is based on 2 parts :

-> One metadata extractor witch detect the file type and use a dedicaced 
loader to construct Exiv2 metadata container. Actually JPEG, PNG and CRW 
files are supported. I have planed to do TIFF/DNG files and any others RAW 
files like NEF (Paco if you is interresed (:=)))) and MRW. The implementation 
is similar to Digikam::DImg container (about loader)...

-> A large collection of widgets to display metadata in sidebar.

I will provide a patch against svn in a near future...

Plan outside 0.9.0 issue :

- add a button to copy metadata info in clipboard.
- add a button to print metadata.
- make Iptc viewer like Iptc Editor about file supported in writting mode 
using Exiv2.
- add Xmp support (I hope that Xmp will be supported to Exiv2 in the future)
- add a metada setup filter like in KPhotoAlbum.

Current Exiv2 problems (correct me if i'm wrong (:=))) :

- The tags descriptions exist in Exiv2 but I can access it easily in my 
implementation...
- The exiv2 lib isn't yet i18n using gettext (like libexif). I suppose that 
point is pending.

Important notice to digiKam developpers : the better way to support more file 
formats in digiKam about metadata extraction (like new RAW files) is to 
contrib on Exiv2 project. I will only make any read only metadata loader in 
digiKam (like for TIFF file). This code could be used later in exiv2 if 
necessary...

Thanks for your comments.

Gilles Caulier.