Bug 466295 - Digikam displays XMP metadata for all video files, even those without XMP metadata in the file.
Summary: Digikam displays XMP metadata for all video files, even those without XMP met...
Status: RESOLVED INTENTIONAL
Alias: None
Product: digikam
Classification: Applications
Component: Metadata-Xmp (other bugs)
Version First Reported In: 8.0.0
Platform: Manjaro Linux
: NOR normal
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-02-23 09:40 UTC by mahikeulbody
Modified: 2023-05-03 08:24 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In: 8.1.0
Sentry Crash Report:


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Description mahikeulbody 2023-02-23 09:40:00 UTC
SUMMARY
Digikam displays xmp metadata for all video files, even those without xmp metadata in the file.

STEPS TO REPRODUCE
1.  Select a video with no XMP metadata embedded into the file (checked with exiftool -xmp:all file)
2. Display the XMP metadata panel

OBSERVED RESULT
XMP metadata is displayed (probably a computed view of the EXIF metadata in "XMP language").

EXPECTED RESULT
The same behavior as for photos : to display only XMP metadata present into the file (there is currently no XMP metadata displayed for photo without XMP metadata into the file).
Comment 1 Maik Qualmann 2023-02-23 10:47:32 UTC
This is currently the intention. For the information obtained from FFmpeg, e.g. bit rate, etc., there are only corresponding tags in the XMP namespace. We want to provide this information. ExifTool uses the "Composite" subgroup for this. There is no metadata standard for video, read about it in the ExifTool forum. ExifTool only writes one standard out of many possible ones. But there are many places in a video where metadata can be found. Some embed them in a thumbnail image e.g.

Maik
Comment 2 mahikeulbody 2023-02-23 12:20:43 UTC
Ok, thank you for this explanation. I understand the intention but I regret that the chosen solution (visualization of this information in the XMP panel) is not consistent with what happens for the photos where only the information present in the file is displayed.

Btw, if I write a Title (or a Caption), Digikam write it into the video file which is fine, but it takes the opportunity to write also some others metadata from the ones shown in the XMP panel, which is questionable ; and not all others XMP metadata, only a sub-part, which is also questionable ; I would expect all of them or none (except the one created by the user, Title in my example).
Comment 3 caulier.gilles 2023-05-03 08:24:35 UTC
@mahikeulbody 

>Ok, thank you for this explanation. I understand the intention but I regret that the chosen solution (visualization of this information in the XMP >panel) is not consistent with what happens for the photos where only the information present in the file is displayed.

The video file format support is partial in Exiv2 and ExifTool, this is why ffmpeg is used to capture important information from file to populate the database. These information are available in metadata sidebar as to be homogeneous.  

>Btw, if I write a Title (or a Caption), Digikam write it into the video file which is fine, but it takes the opportunity to write also some others >metadata from the ones shown in the XMP panel, which is questionable ; and not all others XMP metadata, only a sub-part, which is also >questionable ; I would expect all of them or none (except the one created by the user, Title in my example).

Again video file format metadata support is not perfect in the metadata engines. So if you enable the XMP sidecar support, you will able to do what you want with video metadata. See the online documentation for details :

https://docs.digikam.org/fr/setup_application/metadata_settings.html#sidecars-settings

Gilles Caulier