Hello
1 Why does Tools > Metadata > Edit XMP not display the XMP data that appear in the ExifTool tab?
The author has chosen to propose the edition of some of the most common XMP metadata, because there are hundreds of them ...
2 How can I edit/delete the XMP data that appear in the ExifTool tab?
If the xmp data is not accessible in one of the tabs of the "Tools > Metadata > Edit XMP" window, you will have to use some tricks, which I perhaps may be able to describe if you give an example .
... like this one, designed to delete xmp country code : (PC with Windows)
- Tools>Open with> Configure ... in left column, add exiftool.exe (located in AddOn folder of xnviewmp) . You can rename this field "deleteCC"
- in right column, with a double-click, add parameters "-xmp:CountryCode= " -k
Then , select photos, Open With, click on the command you have built to delete country code of these photos
3 Are the displayed XMP data embedded in the file?
There are two ways to associate xmp metadata with photos.
Either, for formats that support it, embedded in the image file;
Or, for files that do not support embedded xmp, by writing a companion xmp file (sidecar file) next to the photo.
(If you wish, you can force the writing of companion xmp files in any case).
It's up to you to determine if your files have been tagged "embedded" or "companion".
XnViewMP can display both methods, but it's not easy to guess which one it has read
4 Why is Tools > Metadata > Clean grayed out?
Maybe a file format for which Xnviewmp can't edit the metadata ?
For jpg files, it's not greyed ...
5 Why, with a different file (.webp), is Tools > Metadata > Edit XMP grayed out (if XMP data are shown in the ExifTool tab for this .webp file)?
Same answer, I don't remember which formats are supported yet in XnViewMP...
6 To remove all xmp metadata with a call to ExifTool, use the parameters : "-xmp:all= " -k
(The -k parameter holds the ExifTool window in order to read the report.)