Hello trid users,
some days i must handle some Windows Metafile. These have file name
suffix WMF.
So i run trid utility on these WMF examples. Most examples (3700) are
described correctly as "Windows Metafile" by wmf.trid.xml, but with
mime type image/x-wmf. A few samples (23) are described as variant
"Windows Metafile (old Win 3.x format)" by wmf-16.trid.xml, but with
mime type image/x-wmf. One test example is described as "Unknown!"
(See appended output/trid-v-old.txt).
I verified that these are valid books by opening samples with
IrfanView and XnView graphic software.
For comparison reason i also run file command (newest version 5.44) on
such samples. Here all WMF examples are described as "Windows
metafile" (See appended output/file-5.44.txt). With -i option is shows
another mime type (See appended output/file-i-5.44.txt). The test
sample not recognized by TrID is similar to old Win 3.x format. This
start with byte sequence 01000900. The non described variant starts
with sequence 02000900. Unfortunately i myself do not found such an
example. So i do not know if this a third exotic variant or if file
command is buggy for that case.
For comparison reason i also run the file format identification
utility DROID ( See
https://sourceforge.net/projects/droid/). Here all
samples recognized by TrID are described "Windows Metafile Image" by
PUID x-fmt/119 with mime type image/wmf (See appended
output/droid-wmf.csv).
The mentioned mime type by file command and DROID is also found as
registered by IANA. There it is written that image/x-wmf is deprecated
and correct now is image/wmf. But explicitly this is only written for
variant starting with byte sequence D7CDC69A . This variant is handled
by TrID via wmf.trid.xml. So this mime type is now expressed in
updated wmf.trid.xml by line like:
<Mime>image/wmf</Mime>
With the updated trid definition now my WMF LIT examples are described
as before, but now current registered mime type is shown. (see
appended output/trid-v-new.txt). TrID definition and output are stored
in archive wmf_.zip. I hope that my updated definition can be used in
future version of triddefs.
With best wishes
Jörg Jenderek
