Metadata Working Group -- status?

[gakochan]

Hello fellow exiftool fans,

I was doing some experiments on what platforms/apps read what tags. The attached table shows what metadata is displayed by various platforms/programs for 3 versions of the same image, which have had their metadata written as IPTC+EXIF+XMP (IEX), IPTC+EXIF+XMP+MWG (IEXM) or MWG only (M). "–" means "nothing displayed".

I was wondering if the Metadata Working Group was still a thing? Their webpage appears to be unreachable. Its last save by the Internet Archive seems to be October 2018.

Going forward, is it sensible to use MWG tags?

Thanks for any thoughts!

Toby

[Phil Harvey]

Hi Toby,

I don't understand your table.  How do you write Title, Description and Copyright as "MWG"?  The MWG defines only the relationships between EXIF, IPTC and XMP for these tags (well, all except for "Title", which isn't mentioned in the MWG specification at all).  There are no MWG-specific definitions for these.

- Phil

[StarGeek]

By Windows 10 file manager, I'm assuming you mean the desktop Properties window.  If so, then I have to ask about your methodology, as Windows will read XMP, IPTC, and EXIF if they exist for most of their Properties.  See the Windows metadata thread.

For example, Windows "Title" property will these tags
EXIF:ImageDescription
EXIF:XPTitle
IPTC:Caption-Abstract
XMP-dc:Description
XMP-dc:Title

The obvious problem is that three of these tags fall into the "Description" category.  So Windows is mixing "Description" and "Title" into a single property. And for your "Description" column, I'm assuming you're using the "Comments" property, which reads the UserComment in both EXIF and IPTC. These arenn't used with specs like the IPTC Photo Metadata Standard or the MWG standard.

I'm ignoring the Windows XP* tags, as almost no programs outside of Windows will read them.

I was wondering if the Metadata Working Group was still a thing? Their webpage appears to be unreachable. Its last save by the Internet Archive seems to be October 2018.

In this post and this post from a few years ago, they told Phil that they still existed, but since they haven't shown any signs otherwise, I would say effectively, they don't exist.

Going forward, is it sensible to use MWG tags?

In my opinion, yes.  The MWG tags are not tags by themselves, but an easy way to write multiple related tags at the same time.  And the IPTC Photo Metadata Standard basically uses the same mappings, except for the EXIF tags.  At this point, you might as well call them the IPTC tags.

For a beginner, they are a good starting place for dealing with metadata.

And now you have me thinking about seeing if I can make an IPTC module.  Something that's more up to date.  I don't think the -use option has ever been used outside of the MWG tags.

[Phil Harvey]

In this post and this post from a few years ago, they told Phil that they still existed, but since they haven't shown any signs otherwise, I would say effectively, they don't exist.

Thanks for finding this post.  I looked but didn't find it.  I agree that effectively they don't exist.

- Phil

[gakochan]

Hi Phil

Thanks for the prompt reply, Phil. To write the MWG tags I used:

Code Select Expand

exiftool -overwrite_original met_m.jpg \
   -mwg:Description="**MY MWG DESCRIPTION**" \
   -mwg:Copyright="**MY MWG COPYRIGHT**"
The silly names (and corresponding silly names for the EXIF/XMP/IPTC tags) were so I could differentiate what showed up when opening the test image in different apps. I was very surprised that the MWG tags showed up at all, as I had understood they were not tags per se, but would have triggered exiftool writing XMP/IPTC tags!

Toby

[Phil Harvey]

The ExifTool MWG tags are a set of Composite tags that read/write the appropriate EXIF, IPTC and XMP tags.

- Phil

[gakochan]

And for your "Description" column, I'm assuming you're using the "Comments" property

No, not using that. My scripts for the tests were:

For IPTC/EXIF/XMP (iex in the table):

Code Select Expand

exiftool -overwrite_original met_iex.jpg \
  -iptc:ObjectName="**MY IPTC TITLE**" \
  -iptc:Caption-Abstract="**MY IPTC DESCRIPTION**" \
  -iptc:CopyrightNotice="**MY IPTC COPYRIGHT**"\
  -exif:ImageDescription="**MY EXIF DESCRIPTION**" \
  -exif:Copyright="**MY EXIF COPYRIGHT**" \
  -xmp:title="**MY XMP TITLE**" \
  -xmp:Description="**MY XMP DESCRIPTION**" \
  -xmp:Copyright="**MY XMP COPYRIGHT**"
For IPTC/EXIF/XMP/MWG (iexm in the table):

Code Select Expand

exiftool -overwrite_original met_iexm.jpg \
  -iptc:ObjectName="**MY IPTC TITLE**" \
  -iptc:Caption-Abstract="**MY IPTC DESCRIPTION**" \
  -iptc:CopyrightNotice="**MY IPTC COPYRIGHT**"\
  -exif:ImageDescription="**MY EXIF DESCRIPTION**" \
  -exif:Copyright="**MY EXIF COPYRIGHT**" \
  -xmp:title="**MY XMP TITLE**" \
  -xmp:Description="**MY XMP DESCRIPTION**" \
  -xmp:Copyright="**MY XMP COPYRIGHT**" \
  -mwg:Description="**MY MWG DESCRIPTION**" \
  -mwg:Copyright="**MY MWG COPYRIGHT**"
and for just MWG (M in the table):

Code Select Expand

exiftool -overwrite_original met_m.jpg \
  -mwg:Description="**MY MWG DESCRIPTION**" \
  -mwg:Copyright="**MY MWG COPYRIGHT**"
And thank you for the info about the M.W.G.

best,
Toby

[StarGeek]

I have a test file that has over 1,400 tags already set in this post.  There is also an ARGS file (see the -args (-argFormat) option) that you can use to set the data on your own images.

The way I tested things was to load up the test file and see what data is shown.  I then removed this data to see if the program would read any other tag.  Repeat until the program no longer shows data or shows a default value.

[gakochan]

I have a test file that has over 1,400 tags already set in this post.

Thank you!

best,
Toby

[gakochan]

The ExifTool MWG tags are a set of Composite tags that read/write the appropriate EXIF, IPTC and XMP tags.

Agggh! After a few weeks looking at this I think the penny may have finally dropped.  

There are no actual "MWG" tags that get written. Rather, a metadata writer, if given some MWG tag M, will use MWG rules to derive from M a set of EXIF, IPTC and XMP tags (which might not include all those tags) that do the best job of describing M.

Toby

[Phil Harvey]

I think you've finally seen the light.

[StarGeek]

There are no actual "MWG" tags that get written.

One thing we did skip over is that there actually are some MWG tags, but they are part of the XMP group, and not prefixed by MWG:.  The MWG Region tags, group XMP-mwg-rs are the de facto tags for embedding regions such as for facial recognition.  These are the only MWG tags I've seen used.

There is also the MWG Keywords structure (group XMP-mwg-kw) and the MWG Collections structure (group XMP-mwg-coll) but I have never seen them used.

[blue-j]

That's an important point, StarGeek.  Those MWG region fields are definitely still in popular use.  Not as sure about the keywords or collections things.

- J