datetimeoriginal from filename

[keysnapper]

Hi,
I have scans which are renamed like
1940 Text.jpg
1949-03 Text.jpg
1955-04-04 Text.jpg
1955-05-05 Text2.jpg
Only the last file gets an EXIF entry with

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exiftool '-DateTimeOriginal<Filename' DIR because the ninth number is used as hour
all other pics get an XMP entry.
Is there an oneliner to rule them all?

I use Linux Mint.

[StarGeek]

The EXIF:DateTimeOriginal tag requires a time as well as a date.  This is further complicated by the fact that you may not have a month or day.

Normally, the lack of a time is filled with the earliest time for that day, which would be Midnight, 00:00:00.

Will any of these files have a time component in the name? That might complicate things even more

There might be a better way, but this is what I have at the moment, assuming there isn't a time component in the filename and using 01-01 as default month-day
exiftool '-DateTimeOriginal<${Basename;m/(\d{4})(?:-(\d\d))?(?:-(\d\d))?/;$_=$1.($2//"01").($3//"01")} 00:00:00' /path/to/files/

This regex will capture the year and then conditionally capture the month and day if they exist.  Then using defined or operator //, it will assign either the captured value if it exists or default to 01 (see this page).

Example using Windows quoting (reverse of Linux quoting)

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C:\>exiftool -P -overwrite_original -all= Y:\!temp\bbb\b
    1 directories scanned
    4 image files updated

C:\>exiftool -P -overwrite_original "-DateTimeOriginal<${Basename;m/(\d{4})(?:-(\d\d))?(?:-(\d\d))?/;$_=$1.($2//'01').($3//'01')} 00:00:00" Y:\!temp\bbb\b
    1 directories scanned
    4 image files updated

C:\>exiftool -G1 -a -s -DateTimeOriginal Y:\!temp\bbb\b
======== Y:/!temp/bbb/b/1940 Text.jpg
[ExifIFD]       DateTimeOriginal                : 1940:01:01 00:00:00
======== Y:/!temp/bbb/b/1949-03 Text.jpg
[ExifIFD]       DateTimeOriginal                : 1949:03:01 00:00:00
======== Y:/!temp/bbb/b/1955-04-04 Text.jpg
[ExifIFD]       DateTimeOriginal                : 1955:04:04 00:00:00
======== Y:/!temp/bbb/b/1955-04-04 Text2.jpg
[ExifIFD]       DateTimeOriginal                : 1955:04:04 00:00:00
    1 directories scanned
    4 image files read
At least I think that's what I'm doing there.  I was digging deep in order to remember this trick.

Phil, can you verify I'm not messing this up?

[Phil Harvey]

Hi StarGeek,

That's cool.  I've never used the "//" (logical defined-or) operator.  Looking into this, it was added in Perl 5.10.0.

Looks good.

- Phil

[StarGeek]

I could have sworn I picked it up here, but maybe not.

Impossible to search on because off the // in https//:

[keysnapper]

Thank you, Stargeek.
Your 1liner worked.

But because I don't understand perl and regex, I looked for an alternative.

The issue is that DateTimeOriginal is a date-time field and needs a special format.
Using DateFmt does not help.
Eureka! I found out that string fields accept DateFmt if the filename does not start with letters. SEMInfo is for electron microscopy, so never used by me.
Now I could copy human noob readable examples from the forum and the FAQ to clean up the metadata and set the DateTimeOriginal. I couldn't get it to work as 1 Liner so I had to break it up to 2 lines.


Line1
    ---no backup-------------------|---------------------------------repair jpg ------------------------------|----------------------formatted Date to SEMInfo----------------------------------|---not only jpg---

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-overwrite_original   -exif:all= -tagsfromfile @ -all:all -unsafe     '-SEMInfo<${filename;DateFmt("%Y:%m:%d %H:%M:%S")}'     -ext '*'
Line2
    --no backup-----------------|-------------------move date to where it belongs----------|--delete SEMInfo--| --for filenames starting with a letter--

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-overwrite_original   '-exif:DateTimeOriginal<SEMInfo'          -SEMInfo=       '-DateTimeOriginal<Filename'
These commands are for jExiftoolGUI. For use in the terminal insert

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exiftool   -r before and

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<path to dir> after each line.

[StarGeek]

The issue is that DateTimeOriginal is a date-time field and needs a special format.

The tag itself needs to be formatted correctly, but exiftool is extremely flexible on this.  From FAQ #5

Having said this, ExifTool is very flexible about the actual format of input date/time values when writing, and will attempt to reformat any values into the standard format unless the -n option is used. Any separators may be used (or in fact, none at all). The first 4 consecutive digits found in the value are interpreted as the year, then next 2 digits are the month, and so on. [The year must be 4 digits. Other fields are expected to be 2 digits, but a single digit is allowed if the subsequent character is a non-digit.] For EXIF date/time values, all 6 date/time fields must exist ("YYYYmmddHHMMSS"), but XMP date/time values require only the year ("YYYY").

So as long as you have 14 numbers in YearMonthDayHourMinuteSecond order, exiftool will ignore any other characters, including ones inbetween the numbers, and use it as the date/time.  I often get lazy and just grab the numbers in my commands without bothering to format them.

The usual problem is when there are extra numbers such as a copy number or a leading number.  Those have to be removed in some way and that is a fairly common post here.

[StarGeek]

But because I don't understand perl and regex, I looked for an alternative.

And that is also fine.  It's better that you understand what's going on so you can deal with it at a later date without coming here and waiting for a response.

Using a uncommon tag to hold a value temporarily is perfectly fine.