DigiKam 7.9.0 reads ctime instead of mtime, if file contains no metadata

[Maik Qualmann]

The behavior hasn't actually changed, even between 7.1.0 and 7.9.0. The ctime 
is the correct time for the creation date if no date metadata exists. We 
wouldn't change this behavior either. Only in the event that the ctime is not 
valid, i.e. not a correct calendar date, we would use the mtime. If the mtime 
is also not valid, the current date would be used as the creation date.
In current digiKam versions (8.2.0) the mtime is not changed when copying and 
file operations.
You can change the mtime with the TimeAdjust tool without writing metadata.

Maik

Am Freitag, 10. November 2023, 18:58:00 CET schrieb Peter Albrecht:
> Hello list,
> 
> I updated digiKam from 7.1.0-2 (Debian 11) to 7.9.0-1+b2 (Debian 12) and now
> I experience a difference about timestamps read from files.
> Importing a picture (or audio file or video file), which does not contain a
> timestamp in EXIF, to digiKam...
> ... old digiKam 7.1.0 did take the files "modification timestamp" (mtime).
> ... new digiKam 7.9.0 now takes the files "change timestamp" (ctime).
> 
> Why is this a problem for me?
> I have some file in which I do not want to embed metadata like timestamps.
> To keep the information "when was this picture taken / video recorded", I
> write this information to the files modification time (mtime). It is not
> the best solution, but if you handle the file with care (e.g. using "cp
> -a"), you can manage to preserve this information.
> You can't use change time (ctime) for this purpose, since it changes
> everytime you move or rename the file. And there is no easy way like
> "touch" to change the ctime.
> So if digiKam reads the timestamp from a files "ctime", my information "when
> was this picture taken" will not be imported to the digikam database.
> 
> Do you have any idea, why this behaviour changed? Is there a way to
> configure digiKam, using the "mtime" again? Should I file a bug for this?
> 
> Thank you for reading,
> 
> Peter Albrecht
> 
> +++ My Settings:
> 
> [x]: means "checked / enabled"
> [ ]: means "not checked / disabled"
> 
> Settings > Metadata > Behaviour
>   [x] Timestamps
>    ...
>   [ ] Update file modification timestamp when files are modified
>   [x] Rescan files when files are modified
>   [ ] Clean up the metadata from the database when rescan files
> 
> Settings > Metadata > Sidecars
>   [ ] Read from sidecar files
>   [ ] Write to sidecar files
> 
> Settings > Metadata > Baloo
>   [ ] Store metadata from digiKam in Baloo
>   [ ] Read metadta from Baloo
> 
> Settings > Miscellaneous > Behaviour
>   [x] Scan for new items at startup
>      [ ] Fast scan
> 
> 
> +++ Help > Components information
> 
> digikam version 7.9.0
> Libraries:
> XMP SDK: 5.6.0
> Qt WebEngine version: 5.15.11
> Qt: 5.15.8
> Marble: 22.12.1
> Libx265: 3.5+1-f0c1022b6
> LibTIFF: 4.5.0
> LibRaw: 0.21.0
> LibPNG: 1.6.39
> LibPGF: 7.21.07
> LibOpenCV: 4.6.0
> LibLCMS: 2140
> LibJPEG: 62
> LibHEIF: 1.13.0
> LibGphoto2: 2.5.30
> LibCImg: 130
> LensFun: 0.3.3-0
> KF5: 5.101.0
> ImageMagick codecs: 6.9.11
> Exiv2: 0.27.6
> ExifTool: 12.57
> Eigen: 3.4.0
> DNG SDK: 1.5.1
> 
> Features:
> VKontakte support: No
> Rajce support: Yes
> Parallelized demosaicing: Yes
> Panorama support: Yes
> Memory available: 31.3 GiB
> Media player support: No
> LibLqr support: Yes
> LibJasper support: No
> HTML Gallery support: Yes
> HEIF writing support: Yes
> HEIF reading support: Yes
> Exiv2 supports XMP metadata: Yes
> Exiv2 supports Base Media: Yes
> Database backend: QSQLITE
> DBus support: Yes
> Calendar support: Yes
> CPU cores: 12
> Baloo support: Yes
> AddressBook support: Yes