Video `Create Date` with GPS inferred timezone about exiftool-vendored.js

[mceachen]

Currently backfillTimezones is conservative: it doesn't set the time zone for ExifDateTime instances that already "have a zone".

Unfortunately, there isn't a discriminator for those ExifDateTime instances that are UTC because of #defaultToUTC, or because their raw value actually included a zone offset.

Edit: I just added the discriminator, so we can make this change safely now.

[mceachen]

OK, I think this warrants a major release, as the output will be different for people using backfillTimezones.

[mceachen]

Thanks for this research. Is this video metadata directly from a smartphone, or was it edited?

If you could attach all date and time fields coming from exiftool for that file, or just attach the file itself, that might be helpful for me to replicate your table.

(Fwiw, I would have expected defaultVideosToUTC: false, backfillTimezones: true to do what you wanted)

[jrasm91]

It's directly from the phone. In general, I don't think any of the videos from my pixel phones have timezone information in them.

Here's the file: File1.zip

Here's *Date* properties:

jrasm91@jrasm91-ubuntu:Videos$ exiftool -*Date* File1.mp4 
File Modification Date/Time     : 2022:10:26 19:56:17-04:00
File Access Date/Time           : 2023:09:13 13:22:13-04:00
File Inode Change Date/Time     : 2023:09:13 13:21:46-04:00
Create Date                     : 2021:09:06 17:44:16
Modify Date                     : 2021:09:06 17:44:16
Track Create Date               : 2021:09:06 17:44:16
Track Modify Date               : 2021:09:06 17:44:16
Media Create Date               : 2021:09:06 17:44:16
Media Modify Date               : 2021:09:06 17:44:16

Full exif dump

ExifTool Version Number         : 12.40
File Name                       : File1.mp4
Directory                       : .
File Size                       : 4.7 MiB
File Modification Date/Time     : 2022:10:26 19:56:17-04:00
File Access Date/Time           : 2023:09:13 13:22:13-04:00
File Inode Change Date/Time     : 2023:09:13 13:21:46-04:00
File Permissions                : -rwxr-xr-x
File Type                       : MP4
File Type Extension             : mp4
MIME Type                       : video/mp4
Major Brand                     : MP4 v2 [ISO 14496-14]
Minor Version                   : 0.0.0
Compatible Brands               : isom, mp42
Media Data Size                 : 4940337
Media Data Offset               : 40
Movie Header Version            : 0
Create Date                     : 2021:09:06 17:44:16
Modify Date                     : 2021:09:06 17:44:16
Time Scale                      : 10000
Duration                        : 2.97 s
Preferred Rate                  : 1
Preferred Volume                : 100.00%
Preview Time                    : 0 s
Preview Duration                : 0 s
Poster Time                     : 0 s
Selection Time                  : 0
Audio Format                    : mp4a
Audio Channels                  : 2
Audio Bits Per Sample           : 16
Audio Sample Rate               : 48000
Matrix Structure                : 0 1 0 -1 0 0 0 0 1
Media Header Version            : 0
Media Create Date               : 2021:09:06 17:44:16
Media Modify Date               : 2021:09:06 17:44:16
Media Time Scale                : 90000
Media Duration                  : 0 s
Handler Type                    : NRT Metadata
Handler Description             : MetaHandle
Meta Format                     : mett
Image Size                      : 1024x768
Megapixels                      : 0.786
Avg Bitrate                     : 13.3 Mbps
GPS Latitude                    : 33 deg 21' 11.16" N
GPS Longitude                   : 111 deg 51' 46.08" W
Rotation                        : 90
GPS Position                    : 33 deg 21' 11.16" N, 111 deg 51' 46.08" W

[mceachen]

OK, I just checked the relevant code again, and these settings should indeed work.

Here's the validation spec:

22fe149

[mceachen]

Ah -- I misread your expectations: you want both the timezone to default to UTC, and the timestamps to be shoved to Phoenix. Gotcha.

Poking the code with a stick now.

[jrasm91]

Yeah, it's the combination of "don't mess up the timestamp because it is a video" and "please convert it from UTC to X using GPS"

[mceachen]

Pushed. I'll release as soon as GHA validates the tests pass. Details here:

https://github.com/photostructure/exiftool-vendored.js/blob/main/CHANGELOG.md#v2300

fbabbce

[mceachen]

released v23.0.0 🎉

[jrasm91]

Perfect! Thank you for working on this an the fast turn around time. I just wanted to confirm that I've tested against v23 and everything is working as expected. 🙏