Lightroom classic determine date/time of MP4 file

Question

I'm writing to try and figure ou how Lightroom classic determines the date/time of an MP4 file. I've been able to get LR to consistently handle date/time for MP4, but what LR displays isn't what I am expecting.

First, I'm running on Windows 11. I run a utility on my MP4 files which sets the values of "Date created", "Date modified", and "Date accessed" as shown in the following screenshot. In this screenshot, you see that all of the videos are set to be during the 5:00pm hour. However, as you can also see in the screenshot below, "Date" and "Media created" are set to be during the 4:00pm hour. I'm not sure how these date/time values are set, I think it's a quark of the utility I'm using to change the date/time.

When I import these MP4 files into LR, LR somehow determines the "Date Time Digitized" metadata value...does anyone know how LR does this??

Overall, when I import an MP4 into LR, LR always is consistenly 5 or 6 hours AHEAD of the date/time specified in Windows. If LR is using a value from "Date created", "Date modified", and "Date accessed" (as shown in the screenshot above) then LR is 5 hours ahead. If LR is using a value from "Date" or "Media created" (as shown in the screenshot above), then LR is 6 hours ahead. Since I am in the Chicago CST timezone, 6 hours ahead makes some sense to me because that would be London (possibibly UTC) time.

Anyway, does anyone know how LR determines the date/time of an MP4? If so, is there any strategy for LR to display date/time for MP4 files consistently with Windows?

johnrellis · Answer

Some testing with MP4s indicates that LR uses the first of these fields that's non-blank for its notion of capture date:

XMP:DateCreated

EXIF:DateTimeOriginal

QuickTime:CreateDate

"Overall, when I import an MP4 into LR, LR always is consistently 5 or 6 hours AHEAD of the date/time specified in Windows."

Due to a poorly written Apple Quicktime spec (incorporated into the MP4 spec), cameras with Internet or GPS connections typically obey the spec and record the capture date/time in UTC; whereas cameras without Internet or GPS connections typically record the catpure date/time in "local" time (whatever the camera's clock is set to).

See here for the gory details and how LR could handle this mess better:

https://community.adobe.com/t5/lightroom-classic-ideas/p-handle-video-capture-times-for-cameras-obeying-the-quicktime-mp4-standard/idi-p/14007948

The easiest way to correct capture time issues is to use Metadata > Edit Capture Time to shift the capture times of a batch of videos and/or photos by a specified offset.

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