When writing to the UserData:LevelMeter by itself, it writes to both ID-Lvlm and ID-lvlm. If you further write to those tags by tag ID, it creates two new copies of each tag. Would this be working as intended?
This probably isn't very important, as the tag itself hasn't been mentioned here before and only appears in the output on one post.
C:\>exiftool -P -overwrite_original -all= Y:\!temp\Test4.mp4
1 image files updated
C:\>exiftool -P -overwrite_original -LevelMeter=9.9 Y:\!temp\Test4.mp4
1 image files updated
C:\>exiftool -G1:7 -a -s -u -LevelMeter Y:\!temp\Test4.mp4
[UserData:ID-Lvlm] LevelMeter : 9.9
[UserData:ID-lvlm] LevelMeter : 9.9
C:\>exiftool -P -overwrite_original -UserData:ID-Lvlm:LevelMeter=78.4 -UserData:ID-lvlm:LevelMeter=92.6 Y:\!temp\Test4.mp4
1 image files updated
C:\>exiftool -G1:7 -a -s -u -LevelMeter Y:\!temp\Test4.mp4
[UserData:ID-Lvlm] LevelMeter : 9.9
[UserData:ID-lvlm] LevelMeter : 9.9
[UserData:ID-Lvlm] LevelMeter : 78.4
[UserData:ID-lvlm] LevelMeter : 92.6
Thanks for pointing this out. I'll look into it.
Do you have any idea which one is preferred? 'Lvlm' or 'lvlm'?
- Phil
Not a clue. I only came across it while expanding the metadata test args file. The only time it's mentioned in these forums is this post (https://exiftool.org/forum/index.php?msg=61695).
I've gone through all my samples, and I only have one with 'Lvlm' and one with 'lvlm'. Both are MOV files written by very old Kodak cameras. This tag probably shouldn't be writable, but I'll leave it that way. Both tags will be written when you write LevelMeter without a family 7 group name. However, there is a bug in ExifTool that existing Unknown UserData and ItemList tags aren't removed when writing a new value. There are a few other Writable and Unknown tags that are affected by this as well. I'll fix this in version 13.10.
Thanks again for catching this.
- Phil