Modify EXIF data and time for Sony mp4 files

[hamishr]

For my Sony a6500, arw files have the correct Create Date and Date subject created but mp4 files store the Greenwich Mean Time, which means that in my case (South Africa), the time is 2 hours earlier than it should be. When I last searched the internet, I could not find a solution to this problem, so I have been left with the task of updating the time of my mp4 files, which means e.g. converting

2019:11:18 07:46:45 to
2019:11:18 09:46:45+02:00

I am able to do this successfully by manually editing the metadata, but have been unsuccessful in using the Modify EXIF date and time utility. It goes through the process of Updating but the Create Date and Date subject created remain the same and only the Modified Date is updated. The log file generates the following messages:

11.20 07:55:41+87016 [52EC] 01  W> ETWARN:Warning: No writable tags set from E:\hgr\_temp\a6500\2019-11-18\C0013.MP4
  'v:\develop\imatch5\src\imengine\ptetwrapper.cpp(3437)'
11.20 07:55:45+ 3515 [2BAC] 01  W> ETWARN:Warning: [minor] The ExtractEmbedded option may find more tags in the movie data - E:\hgr\_temp\a6500\2019-11-18\C0013.MP4
  'v:\develop\imatch5\src\imengine\ptetwrapper.cpp(2170)'

How can I get Modify EXIF date and  time working correctly?

[Mario]

Movie files are really special and EXIF metadata was never designed to be used with movie files.
Why Sony uses this 30 year old metadata format instead of the more modern and versatile XMP escapes me. Only Sony can know that.

From your post I understand that ExifTool is unable to update the EXIF date and time in your files?
Tip: Open the Output Panel to see the instructions the Modify Date and Time dialog sends to ExifTool, and also the response from ExifTool when it tries to modify the file. This may be helpful to diagnose this further.

Without actually having one of your movie files for testing and probably the help of Phil from ExifTool, I cannot do more.

Note that IMatch 2020 contains a replacement for the old "Modify EXIF..." command. The new feature directly updates the XMP in the database and can not only shift date and time but also set it, set and shift the time zone etc. After updating the XMP timestamps in the database, the next write-back will also update existing EXIF data in the file. If ExifTool can update the EXIF in the file.

[hamishr]

Thank-you for your reply. I  think I will wait for the 2020 version and see how things go and in the meantime modify date and time for these video files manually. I am summoning up the courage to learn exiftool so that I can really understand what is going on.

[Mario]

Usually all you need to do is to set the XMP created/digitized timestamps in the "Default" metadata panel layout.
When IMatch writes back, it synchronizes the data with exiting XMP, EXIF and legacy IPTC metadata in your files. If this fails for some reason, IMatch should still keep the XMP timestamps in the database unmodified.

I cannot analyze this further without an actual video file.
Maybe you can create a 1 second video and attach it? Should be pretty small and still contain all the correct / problematic metadata.