MP4 mediacreatedate before 1970/UTC?

[egekhter]

I have an application that embeds dates into movies digitized from film.

When I try this command:
exiftool -time:all="1945:10:23 00:00:00"  *.mp4

These properties are not set correctly, and it appears a lot of applications will set the date from the mediacreatedate property

Code Select Expand


Media Create Date               : 1975:09:17 17:31:44
Media Modify Date               : 1975:09:17 17:31:44
Track Create Date               : 1975:09:17 17:31:44
Track Modify Date               : 1975:09:17 17:31:44

Any options for not using UTC dates on these properties?

[Phil Harvey]

The QuickTime date/time tags are a real mess.  Some software stores them correctly as UTC, but some software uses local time.  Worse, date/time values are stored as integers, sometimes with a zero time of 1904, and sometimes 1970.

So dates before 1970 are problematic anyway.

But the other complication is that ExifTool uses the standard C library to convert date/time values, and it doesn't handle date/times before 1970.

So at the moment, I don't see a good solution to your problem.  Even if I patched ExifTool to write the value properly, reading it back in a consistent manner would be problematic.

- Phil