Lightroom to DigiKam: reading xmp files

[Simon Frei]

On 07/01/18 14:49, Remco Viëtor wrote:
>
> But, why do you have sidecar files in the first place?
Because users want them, that's why it is configurable. Reason range
from possible file corruption to easier backup (the latter is huge if
you use incremental but not deduplicating backup programs) and probably
there is more.
> I cannot conclude /from that document/ that the scheme "<basename>.XMP" is the 
> *official* standard way of naming sidecar files (I don't have access to the ISO 
> standard documents).
The ISO standards excludes these issues:
    The composition of a resource and the precise association of an XMP
packet with a resource is beyond the scope of this International
Standard. Where feasible, an XMP packet should be physically associated
with the resource that it describes.
Adobe publishes an extension standard that mandates "basename.xmp" but
as they are a player in this temselves this is basically just saying
"our solution is right".

Read only support for basename.xmp should be fairly easy to do. Write
support is hard as you either need to resolve conflicts (as metadata in
db is per file, xmp will be per "basename") or implement this scheme
where one xmp file has data for many pictures (haven't seen any spec yet
standardizing this). This should either be done right (who has time and
interest? I'd guess nobody) or just read only.