[CREATE] XMP : MakerNote

Cyrille Berger cberger at cberger.net
Thu Jun 7 15:01:47 PDT 2007


I am currently working on XMP for Krita, and Gilles Caullier has told me that 
one problem with XMP for photograph is that it can't serialize Makernote 
(small binary chunks inside exif which can be used to manufacturers to extend 
the exif specification to include more information). And searching in google 
for XMP and Makernote, you can see that quiet a lot of people are complaining 
about that.
The problem about those Makernote is the unavailability of their 
specification, some effort has been made to reverse engineered them (a 
summary of the effort is available at exiv2 website: 
http://www.exiv2.org/makernote.html), but the result is far to be exhaustive, 
so there is need to keep the old makernote data chunk with the hope, that in 
the future more information can be exctracted from it (and anyway it's needed 
to save back to exif).

So I propose, one schema for the data chunk:
uri: http://create.freedesktop.org/xmp/MakerNote/1.0
prefix: mkn

With only value:

RawData as a String with the MakerNote encoded in base64

Then as many schema as specification, with an uri of the form 

For instance, for Canon (http://www.burren.cx/david/canon.html)

With tags beeing:
ImageType as string
FirmwareVersion as string
ImageNumber as integer
OwnerName as string
CameraSerialNumber as integer
MacroMode as boolean
Quality as choice
FlashMode as choice

What do you think ?
Cyrille Berger

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