I was searching for some image metadata handling library with following requirements:
- support EXIF, IPTC and XMP
- support fast reading of metadata tags (e.g. for batch loading of image thumbnails with annotations)
- support writing metadata tags
- support both standard and RAW image formats
I found several candidates, but each has some flaw:
- WIC - metadata support is on per-codec basis, not possible to extract XMP or EXIF metadata from PNGs and other formats; RAW codecs may not support metadata consistently
- Exiv2 - the C# wrapper is quite old and there are problems on 64bit platforms
- FreeImage - image has to be loaded in order to read metadata
- Exiftool - excellent, but written in Perl and only the command-line app can be used from .NET - loading info for many images can be very slow
- XmpUtils - unable to extract EXIF tags from other than JPEG files (tried on PNGs)
I am working on photo-management application which needs to have excellent image metadata support...