Syntax Reference

[kkilgor]

Hi there, is there a way to check on the acceptable syntax (expected, or common form) for each of the tags.
For example, does DateCreated require Data Time format with : delimtier or only date.   How about CreateDate.

When I look at my library, there is a high degree of inconsisntency between some of these tags and I am trying to fix them with editing the CSV export in Excel and import back.

Thank you in adv.
Ken

[StarGeek]

For date/time stamps, take a look at FAQ #5. 

To repeat and expand on that FAQ, normally, date/time stamps need to have all of the data of "YYYY:mm:dd HH:MM:SS".  The XMP date/time stamps can be shortened to just partial data as shown in the FAQ, or expanded with subseconds and time zone.  Exiftool will want EXIF time stamps to be written with all of "YYYY:mm:dd HH:MM:SS" numbers and will respond with a "Invalid date/time" warning if any of it is missing, though, as mentioned in FAQ 5, it can be just the raw numbers like "20151111132323", though that is a bit messy to deal with.  You can force partial timestamps into an EXIF tag with the -n option or a trailing hashtag on the tag name.  For example, -EXIF:DateTimeOriginal#=2015:11:11.  I do this fairly often, but without the full timestamp, most software will not display or sort it properly.

Otherwise, read the ExifTool Tag Names page and the appropriate sub-page for the tag you are interested in.  If there is something other than "no" in the writable column, then you can refer to the docs on the main ExifTool Tag Names page to understand what it means.

[kkilgor]

Thank you. This is very helpful but I was hoping to find something for all tags including the non-date tags.  For example, what is TimeScale tag? What values does it accepts sort of thing.  I probably can search them and hunt them down one at a time here and there but I was hoping to find a summary table or something like that for all the tags.

Again thank you so much. Your explanation was very helpful.

[StarGeek]

Thank you. This is very helpful but I was hoping to find something for all tags including the non-date tags.

As I said:

Otherwise, read the ExifTool Tag Names page and the appropriate sub-page for the tag you are interested in.  If there is something other than "no" in the writable column, then you can refer to the docs on the main ExifTool Tag Names page to understand what it means.

If exiftool can write it, it will be on one of the subpages listed there as well as the types of data that can be written to it.   Each sub-page corresponds to a group that the tag belongs to.  If you're not sure of the group, run exiftool -G -a -s FILE to get the group name (or maybe use -G1 in some cases, like if the tag shows up under Makernotes).

For example, what is TimeScale tag? What values does it accepts sort of thing.

The only reference I can find to that is under Apple tags and isn't writable by exiftool.  If that's the tag, then it's something you would have to look elsewhere for to get more information.  Remember, exiftool deals with tens of thousands of tags.  Phil has figured out how to deal with many of them, but quite a few are proprietary and the details about them are not freely available. 

[StarGeek]

This sorta nagged at me, maybe I misunderstood exactly what you were asking

For example, what is TimeScale tag? What values does it accepts sort of thing.

so I came back to post some more. 

If you're looking for definitions as to what various tags are supposed to be used for, rather than just the syntax of how exiftool can write, then there isn't going to be a single source and many tags don't have a publicly defined purpose at all.  For example, GettyImages has a whole bunch of self defined tags that they use in their stock image business.  Exiftool can read them since they're XMP tags, and with a little work, a user-defined config file can be made to write them, but as to their actual purpose, you'd have to ask GettyImages.  And you might not get an answer as they are proprietary.   The same can be said for many other companies.

But for further reading on the most commonly used and supported tags, you can take a look at the Metadata Working Group (Guidelines for Handling Image Metadata pdf) and the IPTC Photo Metadata Standard.  This references will list the most commonly supported tags and their purposes.  Anything more obscure and you're going to have to do a lot of searching and believe me, I've had to go down some deep rabbit holes to get some definitions and at times was unable to retrace my steps, the stuff was so out there.

[kkilgor]

Thank you very much for your explanation and taking the time to answer my question. I think I now have plenty to work with.  Many thanks. Cheers