Adjust all dates/times by duration of a video

[gheppell]

Hello.

Is there a command in the exiftool command processor that will allow me to shift all dates/times by the duration of the file (MP4 videos in my case)?  

I know that I can do this for a specific tag using something like the following as an example:
-FileModifyDate<${FileModifyDate;ShiftTime('-0:0:'.$self->GetValue('Duration','ValueConv'))}

However, I would like to do this for every tag that has a date/time instead of having to do this for each specific tag.  

Any ideas?
Thank you

[Mario]

The ExifTool Command Processor uses the standard ExifTool ARG file syntax. You can use the same commands in the ECP you can use in an ARG file - one argument per line (not one option per line!). You can directly use your command.

Keep in mind that MP4 is a container, it can contain all kinds of data, from video streams to audio streams to captions etc. 
Fiddling with "all" in an MP4 file may have unwanted side-effects, so make sure you know exactly what you are doing...

There is a reason IMatch uses only the two XMP timestamps, even for video files. Don't break things.