Inserting "Category" to an image

[StarGeek]

from your link to "Microsoft Category Tags" I verified, that different than in this list, there ARE tags that can be written.
I tried "Comment" and "Title", both sucessfully.

You have not looked at the data with the -G1 and -a options as Phil mentioned here

When you write to Category, Comment, and Title in an MP4 with exiftool, you are writing to the Quicktime ItemList:Category.  If you Right Click -> Properties menu -> Details tab and write to the Tags entry in Windows and then look at the output with the above options, you'll see that the Microsoft:Category has been written to.

As I said, Windows reads the Quicktime:Comment tag, and re-checking my notes, the Quicktime:Title tag (which I missed in the list above).

Eventually I noticed that different than the values in "Comment" and "Title" (simple strings), "Category" has a multiple string type (separated by comma or semicolon), maybe that's the reason.

The reason is there are multiple tags with the same name in different groups.  Here's some example output showing the Category tag as part of three different groups

Code Select Expand

C:\>exiftool -G0:1 -a -s -category Y:\!temp\Test1.mp4
[QuickTime:Microsoft] Category                  : Windows Tags
[QuickTime:ItemList] Category                   : Itemlist Category
[XMP:XMP-photoshop] Category                    : Exiftool Written Category

It can be even worse with some of the Quicktime tags as the same tag name can appear in different sub-groups.  For example, the Quicktime Author tag

Code Select Expand

C:\>exiftool -G0:1 -a -s -Author Y:\!temp\Test1.mp4
[QuickTime:ItemList] Author                     : Itemlist Author
[QuickTime:UserData] Author                     : UserDate Author
[QuickTime:Keys] Author                         : Keys Author

[vibaulliETF]

625/5000
Thank you StarGeek for reminding me of the -a -G1 option.
I even found out that after deleting the title tag in Windows, the previous value was displayed as the [XMP-dc] Title.
After I deleted it "exiftool -Title = a1.mp4" it got deleted correctly.
These cross-relationships between the different tag groups are a bit confusing for me;)
Now I can put my customized program into action, which first reads the exif meta tags, then deletes everything I don't want, and only then starts to fill the "Comment" and "Title" tags with the correct values.

thanks again

Ulli