[digiKam-users] Synchronizing metadata?

Henrik Hemrin hehemrin at hemrin.com
Thu Feb 3 13:55:28 GMT 2022


Not the answer but factual background, taken from The digiKam Handbook, page 30:

"Everyone knows about database, it is used to store data. As all other photographs management programs, digiKam too uses the database for some obvious reasons like avoiding data duplica- tion, reducing data redundancy, a quick search engine, and greater data integrity. Moreover, the cost of data entry, storage and retrieval are drastically reduced. Additionally, any user can access the data using query language.

Talking in particular about digiKam, the Albums, Album Roots, Tags, Thumbnails, Face Recog- nition Data, Image Metadata, File Paths, Settings etc. are all stored in different database files.

The digiKam actually manages more than one databases. For convenience, it is broadly categorized in three:

	• Core database for all collection properties, i.e. it hosts all albums, images and searches data.

	• Thumbnails database for compressed thumbnails i.e. to host image thumbs using wavelets compression images (PGF format).

	• Face database for storing face recognition metadata i.e. to host face histograms for faces recognition.”


> 3 feb. 2022 kl. 14:09 skrev George Koulomzin <george at koulomzin.com>:
> Thanks for your reply!
> The XMP solution would avoid issues with invalid paths  that I suspect would be a problem if one were to try to copy the actual DB, so it is attractive.
> I've also been reading up on the "remote server" approach.  I would be the best solution if performance is acceptable.  Does anyone have any experience with this? 
> It is not clear to me where the "training" information is kept, i.e. the set of parameters which help the algorithm decide this picture shows John rather than Joseph.  Clearly, sidecars would not be the place.  How would one synchronize that information?
> My environment is:
> Windows 10 OS all around.
> WiFi everywhere, with cat 6 cable to some locations
> 90,000+ image files, with a lot of "duplication" -- I keep both jpg's and raw files.
> Thanks in advance...
> On 2/2/2022 7:27 AM, Henrik Hemrin wrote:
>> George, 
>> On the second question, I would use the XMP sidecar as the key for solution. You set up so DK writes metadata to XMP side car, you bring the latest side car with you between your computers and ask DK data base to read the latest XMP side car file after you have updated it/brought to the other computer. This method of course means you cannot update the same photo on both machines at the same time. 
>> Someone else may elaborate more in detail, but one general level, I believe this can be a simple solution. 
>> I am sure it is possible make a more advanced setup, I guess that kind of effort depends on how many photos, how often etc, if a more automatic proper sync is better. But again, someone else may have that answer. 
>> Best regards
>> Henrik Hemrin
>>> 1 feb. 2022 kl. 14:25 skrev George Koulomzin <george at koulomzin.com <mailto:george at koulomzin.com>>:
>>> Hello, I a new to the list, so please forgive me if these questions have been answered.
>>> the archive is organized by month.  Is there a way of seeing thread topics by year, or longer?
>>> how can one synchronize tag metadata (e.g. faces) across two computers.  I have a desktop pc with ALL my photos and a laptop with SOME of my photos (laptop is always a subset).  I've done face recognition on the laptop (subset); can I port the resulting metadata back to the pc so as not to have to repeat all the training?
>>> Thanks in advance!
>>> -- 
>>> George Koulomzin
>>> 7 Bridge Hill Lane, 
>>> PO Box 781
>>> Bridgehampton, NY, 11932
>>> (h) 631-537-4956
>>> (c) 914-393-6179
> -- 
> George Koulomzin
> 7 Bridge Hill Lane, 
> PO Box 781
> Bridgehampton, NY, 11932
> (h) 631-537-4956
> (c) 914-393-6179

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