Proper timestamps for videos

Question

I am trying to combine a set of videos from different people and therefore from different smartphones into a single folder of files, so that they can be viewed together in a chronological order.

For pictures, this is easy, all pictures I encountered have the DateTimeOriginal timestamp, which works well. For videos, not so much. I used exiftool -G1 -a -s to extract the metadata.

I came to the conclusion, that QuickTime:CreateDate and QuickTime:ModifyDate are the tags I need to investigate. There are also Track1..x:CreateDate and Track1..x:ModifyDate but which all seem to inherit their date from the QuickTime values. My Samsung phone sorts videos by the QuickTime:CreateDate timestamp.

Now the issue: for the android devices, the CreateDate and ModifyDate are identical. Both timestamps reflect the time, when the video recording ended. However both android devices have the record start date in their filenames, which is not present in the metadata. The iPhone stores the record start time in CreateDate and the record end time in ModifyDate. Honestly, this seems to be the proper way to me.

The question: is there a proper way to set the timestamps in the metadata? I'd say, that the iPhone is doing it right, whereas the android devices don't. I can set the CreateDate for the android videos to the record start date by subtracting the duration of the video.

Answer 1

You can check movie times with:

exiftool -a -G1 -s -fileOrder5 FileName -api LargeFileSupport=1 -api QuickTimeUTC=1 -Time:All .

1. Usually movie's internal metadata 'QuickTime:CreateDate' sets the date and time. It should be UTC and that commands reports it using the computer's time zone location (standard time New York EST -05:00, Berlin +01:00, for example). DST for that date is also automatically set (daylight saving time New York EDT -04:00, Berlin +02:00, for example).

If present, the following internal metadata tags override previously mentioned time or time zone, and the time zone might affect sorting up to ±12 hours if it happens to be present in some movie (in macOS 14 Sonoma Photos.app, YMMV):

2. GPS location in 'Keys:GPSCoordinates' or 'UserData:GPSCoordinates' sets the time zone. Keys overrides UserData if both exist (Photos ignores this UserData tag in .mp4 and .m4v).

3. Date in 'Keys:CreationDate' or 'UserData:DateTimeOriginal' sets the time and time zone, and it overrides all other time and time zone tags above. Keys overrides UserData if both exist (Photos ignores this UserData tag in .mov). iOS (8.4)-9 and newer inserts 'Keys:CreationDate' to its movies.

For example:

[MacOS]         FileCreateDate                  : 2001:01:01 12:00:00-05:00
[System]        FileModifyDate                  : 2001:01:01 12:00:00-05:00
[QuickTime]     CreateDate                      : 2001:01:01 12:00:00-05:00
[UserData]      DateTimeOriginal                : 2001:01:01 12:00:00-05:00
[Keys]          CreationDate                    : 2001:01:01 12:00:00-05:00
[UserData]      GPSCoordinates                  : 40.74842 -73.98561 443.2
[Keys]          GPSCoordinates                  : 40.74842 -73.98561 443.2

See also:

https://discussions.apple.com/docs/DOC-250002750