[digiKam-users] --> Normal Tags and FaceTags

[marcpalaus at hotmail.com]

Hi Alex,

for what I have seen, face tags and normal tags are deeply intertwined 
in digikam. I already had some issues with this topic in the past (see 
https://bugs.kde.org/show_bug.cgi?id=392007 ).

Basically, a face tag is a set of coordinates (to draw a rectangle) with 
an associated name that is saved in the XMP metadata. And a normal tag 
or keyword can be written in the IPTC or XMP metadata (but in different 
fields). Normal tags can form a hierarchy, if the software supports it, 
although I don't think there is a single standard (I think digikam uses 
lighroom, microsoft photos, acdsee and mediapro "standards" so as to be 
as compatible as possible) but face tags cannot store a hierarchy, so 
they will always be a flat list.

However, when scanning metadata, if digikam finds the same name in a 
normal tag and a face tag, tries to position that face tag into the tree 
where the normal tag is (by default, under "People"). That way you can 
have hierarchical face tags.

In your case, for some reason, the face tags might have not been saved 
correctly to your files. The names you see on People/* are probably just 
regular tags, not face tags.

Can you check using an external tool that your pictures indeed have the 
faces saved in them? Using http://exif.regex.info/exif.cgi or the 
command exiv2. Or just going to the Metadata/XMP panel in digikam and 
see if you see any mentions to rectangles or face regions in there.

I hope I helped.

PS: if, for some reason, you still have a copy of the old database, you 
could use it, re-write the metadata in the files (or sidecars), and then 
the newer version of digikam should be able to see these changes.

El 24/6/20 a les 2:14, Alex Antão ha escrit:
> Hi all.
>
> Could somebody explain how exactly Digikam treats Tags and FaceTags ?
> I mean, how does it recognises when a Tag is a Normal Tag and when it 
> is a FaceTag ?
>
> That's because I came from an upgrade from Digikam 6, I had a lot of 
> FaveTags already setup, and I write all into the file.
> Sometime, already on Digikam 7, I think, it seems it lost the 
> database, because when I opened it, it was empty and DK started 
> scanning the Library...
>
> From there, My FaceTags seemed to get vanished. I still have tons of 
> photos with the Tags marked as People/Alex (for example), but it seems 
> to be a normal Tag. If I go to the People Tab, I am not there.
>
> So, I recognised myself on some photos and my name started showing 
> there, but all my tons of photos that are tagged with my name are not 
> being shown on People Tab.
>
> If I go to Tag Manager, I can see ALL Tags, there's a Tag of any 
> people recognised before. If I Drag them to the People Subtree, DK 
> says it already has a Tag with that name and asks me to Merge. If I 
> merge, the process says it is syncing the Face Database, but after 
> that only new new recognised photos are kept. Every other looses it's 
> Tag.
>
> Why that ?? I'd like to understand to see if I do not loose all 
> recognised photo I have...
>
> Thanks....
>
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