The composite tags SubSecCreateDate, SubSecDateTimeOriginal, and SubSecModifyDate are not shiftable, but do not issue a warning, only returning Warning: No writable tags set from...
If the -v3 option is added, Composite:SubSecDateTimeOriginal is not shiftable will be displayed. Adding this to the warnings would help figuring out why the no writable tags warning is happening.
I could maybe change this to a -v warning, but I hesitate to go higher than that. I would rather not have any warnings when someone does this:
> exiftool -time:all+=1 a.jpg
1 image files updated
If ExifTool warned for this, we would have:
> exiftool -time:all+=1 a.jpg
Composite:SubSecCreateDate is not shiftable
Composite:SubSecDateTimeOriginal is not shiftable
Composite:SubSecModifyDate is not shiftable
1 image files updated
If I change this to a -v warning, we would have:
> exiftool -time:all+=1 -v a.jpg
Composite:SubSecCreateDate is not shiftable
Composite:SubSecDateTimeOriginal is not shiftable
Composite:SubSecModifyDate is not shiftable
Warning: Invalid date/time (use YYYY:mm:dd HH:MM:SS[.ss][+/-HH:MM|Z]) in XMP-xmpMM:VersionsModifyDate (PrintConvInv)
======== a.jpg
Rewriting a.jpg...
Editing tags in: APP0 APP1 APP13 CIFF ExifIFD GPS GSpherical IFD0 IPTC ItemList JFIF Keys KodakIFD MIE-Doc MIE-GPS MakerNotes Microsoft PDF PNG Photoshop PostScript QuickTime Track# UserData XMP
JPEG APP1 (182 bytes):
Rewriting IFD0
Rewriting ExifIFD
JPEG DQT (130 bytes):
JPEG SOF0:
JPEG DHT (73 bytes):
JPEG SOS
1 image files updated
Which I think is acceptable.
- Phil
Sounds good. I was having problems troubleshooting a StackExchange question where they were trying to shift SubSecDateTimeOriginal and I couldn't figure out why it wasn't working.
OK, great. I'll make the change in the next version.
- Phil