Write to XMP CreationDate from CreateDate

[IHateMetadata]

Hey all, I've been stuck on this for a few hours now as a exiftool rookie 

I have a GoPro which has written mp4 files with the CreateDate specified in local time (not UTC). I want to somehow provide some XMP sidecar metadata to my videos so that applications understand the correct time these videos were taken.

Relevant output for my videos:

$ exiftool -a -time:all 01.MP4
Create Date                     : 2021:01:04 10:06:53
Modify Date                     : 2021:01:04 10:06:53
Track Create Date               : 2021:01:04 10:06:53
Track Modify Date               : 2021:01:04 10:06:53

One application I use supports reading `CreationDate` as a priority, so I would like to write an XMP sidecar which includes `CreationDate` and my timezone. Here's what I have so far:

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$ exiftool -ext mp4 -api QuickTimeUTC -XMP:CreateDate -XMP:CreationDate -dateFormat "%Y-%m-%dT%H:%M:%S.000+13:00" -w xmp -X .
This command isn't quite working, and I'm wondering if anyone knows how I could get it to work. I know that

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exiftool -ext mp4 -api QuickTimeUTC -CreateDate -dateFormat "%Y-%m-%dT%H:%M:%S.000+13:00" -w xmp -X .will produce an `01.xmp` file with the contents of

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<?xml version='1.0' encoding='UTF-8'?>
<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'>

<rdf:Description rdf:about='./01.MP4'
  xmlns:et='http://ns.exiftool.org/1.0/' et:toolkit='Image::ExifTool 12.77'
  xmlns:QuickTime='http://ns.exiftool.org/QuickTime/QuickTime/1.0/'>
 <QuickTime:CreateDate>2021-01-04T23:06:53.000+13:00</QuickTime:CreateDate>
</rdf:Description>
</rdf:RDF>which is *pretty* close, however I need the tag to be named "QuickTime:CreationDate" rather than "CreateDate".

Any ideas?! Or am I going in the wrong direction here, and there is a nicer way to produce date+time+timezone information for my videos in XMP sidecar?

[IHateMetadata]

I notice from the PDF tag docs that I should probably specify that it is actually `pdf:CreationDate` that I need written, not under `QuickTime`.

I tried to use my commands and fiddle around to get a new `pdf:CreationDate` written, but I couldn't get anywhere

[IHateMetadataLess]

I didn't realize that the forum times logins out after 1h, and lost my password to my new account, so I'm sorry but I had to make another account.

With a bit of exploring on forums, the man page, and various pages, I managed to get exactly what I needed! I use the below command:

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exiftool -ext mp4 -dateFormat "%Y-%m-%dT%H:%M:%S.000+13:00" "-CreationDate#<CreateDate" -o %d%f.xmp .

very satisfying to finally get a working command! Looks like I was incorrectly using `-X` and I needed to force exiftool to reformat my dates with the `#` in order to use my `-dateFormat` specified.

Thanks for an awesome tool!

[StarGeek]

Edit: See Phil's answer below

I'm trying to understand why you are forcing the date to be in a non-standard format.  By default, exiftool will write the date correctly for XMP files, which would use colons, not dashes, e.g. 2021:01:04T23:06:53.000+13:00.  Non-standard XMP might be read incorrectly.

[Jean-Pierre]

There is an EXIF metadata standard for dates which had defined YYYY:mm:ddTHH:MM:SS
and a newer ISO-8601 international standard which asks to display dates as  YYYY-MM-DD  (in order to better distinguish them from time strings  hh:mm:ss ).

I would very much appreciate an easy way in exiftool (like a format option "-iso8601 [T|_]") to display date-time strings in this ISO-8601 format with dashes in the date part and an optional date|time separator.

see Wikipedia on ISO8601:
"Separating date and time parts with other characters such as space is not allowed in ISO 8601, but allowed in its profile RFC 3339.[37]"
   This says:
"5.6. ... NOTE: ISO 8601 defines date and time separated by "T". Applications using this syntax may choose, for the sake of readability, to specify a full-date and full-time separated by (say) a space character."

In my interpretation that means that examples then preferably should look like this (for a machine-readable time instant):
   2023-08-20T18:39:57+02:00   using -iso8601 T   (in case of a known time zone)
equivalent to UTC time
   2023-08-20T16:39:57Z        using -iso8601 T   (in case that the known time zone is UTC)
or (in separate date and time groups for human readers when it is obvious, that it's about local time):
   2023-08-20 18:39:57         using -iso8601
   or
   2023-08-20_18:39:57         using -iso8601 _

[Phil Harvey]

When writing XMP:CreationDate, ExifTool automatically formats the stored value properly according to ISO8601.  You don't need the -d option.

- Phil

[StarGeek]

I would very much appreciate an easy way in exiftool (like a format option "-iso8601 [T|_]") to display date-time strings in this ISO-8601 format with dashes in the date part and an optional date|time separator.

See the -d (-dateFormat) option.

You can set this as a default option in your .ExifTool_config file in the %Image::ExifTool::UserDefined::Options section (see example.config file)

Example:

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# Specify default ExifTool option values
# (see the Options function documentation for available options)
%Image::ExifTool::UserDefined::Options = (
    DateFormat => "%Y-%m-%d %H:%M:%S",
);
It can still be overridden with with a different format with the -d (-dateFormat) option on the command line.

[StarGeek]

When writing XMP:CreationDate, ExifTool automatically formats the stored value properly according to ISO8601.  You don't need the -d option.

My mistake.  I never really took a look at the raw XMP for date/time values.

[Jean-Pierre]

Thanks to StarGeek  "You can set this as a default option in your .ExifTool_config file"  for the hint with the exiftool config file; I was not aware of this option.
Defining the personal standard format in this file is a good way to do it.
And I understand that you do not need anything else from the (quite long) example config file, I just used the 5 lines which you posted.


However, I had already tried the formatting options with -d(-dateFormat) and was frustrated that  "This option ... ignores timezone information if present." I wanted to display Date/Time-information including time zones in ISO8601 format! And I wanted to use the same command for photos and videos - so appending OffsetTimeOriginal is not an option - that command fails for videos !

Finally I found a hint to the %z and %Z (formatting???) options somewhere in this forum, but they behave strangely (examples below created with a MP4-video; Exiftool 12.5.8 on Windows 10), and I could not find any exact documentation on these.

1) Standard format:
LocalTime: $MWG:DateTimeOriginal; CreateDate(UTC): $CreateDate
produces
LocalTime: 2023:07:28 16:10:16+02:00; CreateDate(UTC): 2023:07:28 14:10:22Z

Desired ISO8601 output format:
I hoped to be able to create the ISO8601 format with just the dashes in the date part of the standard output:
LocalTime: 2023-07-28 16:10:16+02:00; CreateDate(UTC): 2023:07:28 14:10:22Z


2) Time Zone with %z format:
LocalTime: $MWG:DateTimeOriginal; CreateDate(UTC): $CreateDate -d[n&l]%Y-%m-%d %H:%M:%S%0f %z
produces
LocalTime: 2023-07-28 16:10:16 +0200; CreateDate(UTC): 2023-07-28 14:10:22 +0000

3) Time Zone with %Z format:
LocalTime: $MWG:DateTimeOriginal; CreateDate(UTC): $CreateDate -d[n&l]%Y-%m-%d %H:%M:%S%0f %Z
produces
LocalTime: 2023-07-28 16:10:16 W. Europe Summer Time; CreateDate(UTC): 2023-07-28 14:10:22 W. Europe Summer Time
 

Questions:
a) Is it possible to keep the TimeZone format (with ":" between hours and minutes, and "Z" for UTC) of the standard output (that would be exactly the ISO8601 way)?
b) The %z seems to be a format option and is pretty close to the desired format; can it be modified to contain the ":" (and maybe "Z")?
c) Why is the %Z option producing the same "W. Europe Summer Time" (i.e. +01:00, and the same as Central Europe Time, which is my actual time zone) although DTO is +02:00 and the same for CreateDate, although this is definitely in UTC ? It does not change at all, no matter what value the time zone has. So it is probably no formatting option (with text display of the time zone), but just indicating the actual time zone to which my computer is actually set ? Where do I find documentation on these options?


Jean-Pierre

[StarGeek]

Finally I found a hint to the %z and %Z (formatting???) options somewhere in this forum, but they behave strangely (examples below created with a MP4-video; Exiftool 12.5.8 on Windows 10), and I could not find any exact documentation on these.

See Common Date Format Codes. Most of these codes are part of the OS's strftime function, though some, like %z/%Z are created by exiftool.

A couple of these codes are not supported by Windows, though I can't remember which at the moment.

a) Is it possible to keep the TimeZone format (with ":" between hours and minutes, and "Z" for UTC) of the standard output (that would be exactly the ISO8601 way)?

It depends on what you are doing. Listing the data directly on the command line (e.g. exiftool -DateTimeOriginal file.jpg) will use the format set by -d globally.

But I notice you are using the dollar sign to prefix tag names, which suggests that you are using -p for output or copying the data to other tags.  In that case you can set the date format individually by use DateFmt helper function. For example (quotes here are Windows CMD, swap them for Mac/Linux)
"${CreateDate;DateFmt('%Y-%m-%d %H:%M:%S')}"

b) The %z seems to be a format option and is pretty close to the desired format; can it be modified to contain the ":" (and maybe "Z")?

Hmmm... It doesn't appear so.  If Phil doesn't see it here, you might ask for it in the Feature Request subforum.

c) Why is the %Z option producing the same "W. Europe Summer Time" (i.e. +01:00, and the same as Central Europe Time

Note #3 on the Common Format Codes table linked above

The %Z format code ignores any time zone specified in the date/time value, and returns the system time-zone name for the given date/time interpreted as a local system time.

[StarGeek]

Since I missed this

I notice from the PDF tag docs that I should probably specify that it is actually `pdf:CreationDate` that I need written, not under `QuickTime`.

I tried to use my commands and fiddle around to get a new `pdf:CreationDate` written, but I couldn't get anywhere

PDF Tags are the old standard for PDFs and can only appear in PDFs.  They cannot appear in any other file type.  The XMP-pdf tags are the newer standard and I think are what Adobe is focusing on, though I don't deal with PDFs enough to be sure.  These can be used in any file type that allows XMP data.

[Jean-Pierre]

b) The %z seems to be a format option and is pretty close to the desired format; can it be modified to contain the ":" (and maybe "Z")?

Hmmm... It doesn't appear so.

It looks like that using the standard exiftool date/time format and twice replacing the ':' with '-' using the substitute command s/// does the job. The ' '-delimiter between date and time is definitively supported by the ISO 8601 formatting rules; it is even used as an example on the ISO8601 heading page:

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LocalTime: ${MWG:DateTimeOriginal;s/:/-/;$_;s/:/-/}; CreateDate(UTC): ${CreateDate;s/:/-/;$_;s/:/-/} LocalTime: 2023-07-28 16:10:16+02:00; CreateDate(UTC): 2023-07-28 14:10:22Z

And here is the version with underscore delimiter

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LocalTime: ${MWG:DateTimeOriginal;s/:/-/;$_;s/:/-/;$_;s/ /_/}; CreateDate(UTC): ${CreateDate;s/:/-/;$_;s/:/-/;$_;s/ /_/} LocalTime: 2023-07-28_16:10:16+02:00; CreateDate(UTC): 2023-07-28_14:10:22Z

and the machine-readable 'T' delimiter from pure ISO8601

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LocalTime: ${MWG:DateTimeOriginal;s/:/-/;$_;s/:/-/;$_;s/ /T/}; CreateDate(UTC): ${CreateDate;s/:/-/;$_;s/:/-/;$_;s/ /T/} LocalTime: 2023-07-28T16:10:16+02:00; CreateDate(UTC): 2023-07-28T14:10:22Z


Beware: the 'Z' only shows up if it was explicitly written into the date&time tag; writing '+00:00' does not convert to 'Z' automatically. In order to mark CreateDate clearly as UTC time when this is the case (some older cameras had used CreateDate in local time, and their metadata is still around in my media collection), I have decided to regularly apply the command

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-CreateDate<${CreateDate}Z
I have learned a lot about Perl substitution and translation these days... Thanks for the examples I found in the forum, which led me to the right Perl tutorial pages!

Now I have only one remaining question: is there a way to define one of these in the .ExifTool_config file  or some  ISO8601 API ? (similar as proposed here)

Jean-Pierre

[StarGeek]

Nothing other than what has been mentioned here.