Advanced formatting into non-existing tag MWG: tag?

[ne17]

version 12.40 on windows command line
The code at the bottom works in all cases to fill the MWG:Description tag from the Photoshop Headline tag if it is used, or one of the City + Location / State / Country tags - choosing the lowest one filled.

However if I start with -MWG:Description<${MWG:Description;

     If the MWG:Description tags do not already exist they are created (XMP-dc:Description & Exif-IFD0:ImageDescription - but empty without having the text copied from Headline or location tags.

     If I run the command again (ie the MWG:Description tags exist) - the text is copied as I expect.

I struggle with the -tagsfromfile and advance formatting documentation to work out whether this is expected (or is just a quirk of using MWG:Description) - and I have a workaround, but thought I'd post this to help others / see if there is a better way of doing what I want.

Code Select Expand


exiftool "-MWG:Description<${Filename; { my $mydesc=$self->GetValue('MWG:Description');
                                                               my $myhead=$self->GetValue('XMP-Photoshop:Headline');
                                                               my $mycountry=$self->GetValue('MWG:Country');                                                                                             
                                                               my $mystate=$self->GetValue('MWG:State');
                                                               my $mycity=$self->GetValue('MWG:City');
                                                               my $mylocn=$self->GetValue('MWG:Location');
                                                               if( length($myhead)) { $_ = $myhead; }
                                                               elsif( length( $mycity)) {$_ = $mycity;
                                                                                         if( length( $mylocn )) {$_ = $_ .' '. $mylocn; } }                                                                                 
                                                               elsif( length( $mylocn)) {$_ = $mylocn; }
                                                               elsif( length( $mystate)) {$_ = $mystate; }
                                                               elsif( length( $mycountry)) {$_ = $mycountry; }
                                                               else {$_ = undef; } 
                                         } 
                           }" -fast2 -use mwg -ext DNG -charset filename=utf8 -charset exif=utf8 -progress -m .


[StarGeek]

Remove the -m (-ignoreMinorErrors) option.  From the docs
     Note that this causes missing values in -tagsFromFile, -p and -if strings to be set to an empty string rather than an undefined value

[Phil Harvey]

Wow, such a complex example, it took me a while to figure out what you were trying to do.  But I think your problem is simple:  The advanced formatting doesn't have any affect on a non-existent tag, even if the -m option is used.  This is correct.  It is like this because I never anticipated people would want this, and it would require specialized code to achieve.

- Phil

[ne17]

Phil,
Many thanks for confirming my observation is a (non-) feature rather than a bug and confirming it isn't because of the MWG:

I confess I'd missed that part of documentation of -m - but had tried both with and without -m.  As I couldn't see anything stopping me using ${filename which must exist, rather than any other tag which might not, I thought it worth posting this.

I've been using exiftool for probably 10 years (through geosetter mostly and exiftoolgui) building commands with -if ....   -execute pairs but they becuase of multiple read / write passes thought the file they take a while to run.
After finding the ability to write Perl within a command last weekend I thought If .. Then .. Else would elimate the multiple passes and had to test it  - and to me this is easier to understand than the -if conditions i had used before. 
If I find a use for Perl's Switch within my workflow i'll post that too.

Nigel

[Phil Harvey]

Hi Nigel,

This is a very extreme use of the advanced formatting feature, and it isn't really meant for something like this.  For really complicated logic like this you should look into creating a user-defined Composite tag in your own config file.

- Phil

[ne17]

Phil,

Thanks for the words of caution - I confess I've looked at config files a couple of times but was scared by them - now I've got 3 functions I need working using advanced formatting I'll stick with them until they break, but will also investigate config files again (this time with a bit more background knowledge)

Also I've circumvented the glitch I had writing to a non-existent tag with the -m option set (which I need because of lots of bad maker notes warnings)