Import back video into iPhone after adjusting time & location in Photos app on macOs

While travelling, I like to exchange photos/videos via WhatsApp with other people. Doing it usualy at night, or a few days later, the time of the received item needs to be adjusted in order to have a clean time related photo album on the iPhone.

I use the Photos app on my mac in order to change the time & location, export the new item in my desktop and then send it back to the iPhone via AirDrop (at this time I actually get 2 items : the old one with the "wrong" time and the new one with the "correct" time).

The issue is that it doesn't apply to video, the new timeline is the one of the exportation (i.e a moment ago). But everything is fine with the photos...

Note that the new video time do change correctly on the Photos app when adjusting it.

Is the process to export back video into the iPhone is different than the process to export back photo ?

I use Mojave 10.14.6 with Photos 4.0 & iOs 12.4.1

I can't give you a simple answer, but perhaps I can point you in the right direction.

What you are doing when you change the time/date on your photos is changing its metadata. Metadata is text contained within the file that is read by programs such as the Mac OS Finder when you use Get Info, photo programs, etc... Some programs allow you to edit the metadata, such the Image-->Adjust Date and Time... menu item within the Mac OS Photo app.

More generally, media file metadata can be changed using programs called metadata editors. For example, exiftool is a command-line metadata editor that is available on Windows, Mac, etc... TagScanner is a WYSIWYG metadata editor on Windows.

Both of the above are quite powerful, but also have a learning curve to use them. I'm guessing you'll want a simple editor for Mac OS, but I can't recommend one since I've been happily using the above for my needs. I briefly looked into the availability of metadata editors for the iPhone and found a couple (e.g., Photo Investigator, MetaPho) that claim to do what you want, but cannot be tested for free (they cost $3-$4).

One other thing: there are usually multiple types of date-timestamps for each file, so another thing you may need to discover is which is important for your needs. For example, using the Terminal command exiftool file.mp4 I see 9 timestamps for a recent movie I was sent via WhatsApp:

File Name                       : file.mp4
File Modification Date/Time     : 2019:09:11 10:24:45+02:00
File Access Date/Time           : 2019:09:11 10:24:44+02:00
File Inode Change Date/Time     : 2019:09:11 10:24:58+02:00
...
Create Date                     : 2019:08:18 13:04:29
Modify Date                     : 2019:08:18 13:04:30
...
Track Create Date               : 2019:08:18 13:04:29
Track Modify Date               : 2019:08:18 13:04:30
...
Media Create Date               : 2019:08:18 13:04:29
Media Modify Date               : 2019:08:18 13:04:30

(to focus on the timestamps, I've omitted most of the exiftool metadata listing)

So, thanks to @Tony M, I used ExifTool in order to change the metada of my video file with the line : exiftool -quicktime:createdate="YYYY:MM:DD HH:MM:SS" path/my_file_name.file_ext