This is possibly an odd case, but I would certainly appreciate any help.

I prepare an ARGFILE, in utf-8, with XMP tags like -xmp-dc:title=. Exiftool writes the data correctly to jpegs.

I then (1) change the tags to the corresponding IPTC ones, e.g. -xmp-dc:title= to -iptc:ObjectName=, and (2) use iconv to convert the ARGFILE encoding from utf-8 to iso-8859-7 (Greek), as most programs do not read utf-8 IPTC. The resulting file is read correctly by text editors.

However, when exiftool tries to write the data to jpegs it returns "Warning: Malformed UTF-8 character(s)". The cause seems to be the Greek characters.

Both exiftool and iconv are well established, so perhaps I do something out of place. But if not, is there a way exiftool can accept the iconv output? Or is there another standard encoding conversion tool that exiftool is happy with?

Many thanks in advance,
pdi

Yes, ExifTool now translates coded characters for IPTC. See FAQ #10 for details.

You can use the -L option when writing IPTC if you want to disable translation of special characters.

- Phil

This works because 1) ExifTool assumes IPTC in the file is coded in Latin1 unless the recorded CodedCharacterSet is "ESC % G" (UTF8), and 2) the -L option specifies the external character set as Latin1.

When the recorded character set is the same as the external character set, no translation is performed.

I hope this makes a bit more sense now. :)

- Phil

I understood your confusion, but I guess you didn't understand my explanation.

It is really fairly simple. You give ExifTool a string of bytes and tell it what character encoding was used. As long as ExifTool thinks that the internal and external character sets are the same, then no translation is performed and the bytes are passed through unchanged. (This is the behaviour of older ExifTool versions for IPTC information.)

As long as ExifTool is not translating the text, it is totally irrelevant what character set is actually used since the bytes are passed through unchanged. So as long as ExifTool believes there is no need to translate the text, you are free to use whatever character set you like.

I can see how this could be confusing.

If possible, it is best to use UTF8 to avoid this confusion.

- Phil

I'm glad it makes a bit more sense now.

When writing information, ExifTool uses the value of CodedCharacterSet to determine how to encode the text. If CodedCharacterSet is being written at the same time as text, the new character set is used. If no CodedCharacterSet exists and none is written, then Latin1 is assumed.

The special character handling in IPTC is a real mess. The way ExifTool originally handled it (by never translating) was simplest, but it seems that other applications most commonly assume Latin1 characters (contrary to the actual IPTC specification) so ExifTool was displaying special characters written by these applications incorrectly. This is the reason for the change.

If enough people have problems with this, I am open to changing it back again.

It is a pity that not many applications support UTF8 in IPTC, because this is the best solution. The original IPTC specification used ISO 2022, which is a real can of worms and hence isn't well supported either, but UTF8 support was added as a revision to the IPTC specification (I believe), and is a much better solution.

- Phil