ExifTool Forum

[Originally posted by dbrb2 on 2008-02-28 13:21:33-08]

Hi,

I have a directory full of geocoded images. I need to extract info into an XML file:

http://bbarker.co.uk/photography/London_2_Paris/exif.xml

This file can then be parsed by a website to display them on a map. I initially coded this in php, looping through each image and using exif_read_data(). This worked, but I found that on many images I got a large number of errors complaining about the headers (and no exif data returned, even though other software had sccesfully read the headers) and hence many images mere missing from the XML file. See here:

http://bbarker.co.uk/photography/London_2_Paris/
 

I then found this library.
I ran some of the same problem photos through this parser (using the windows tool) and it worked fine on all of them, so I am tempted to use the php interpreter in php to use this function. Any ideas how well this might work?

Also, can anyone explain why the native php function gives the errors it does? Is it just quite buggy?

Cheers,

Ben

[Originally posted by exiftool on 2008-02-28 14:25:35-08]

I can't help you with your PHP problem, but with a bit of work ExifTool
could be used to generate an XML file in this format.  The commands
would be as follows:


where DIR is the name of a directory containing the images.

This command uses a "prt.fmt" file containing the following line:

<photo FileName='$filename' Width='$imagewidth' Height='$imageheight'
Date='$mydate' Time='$mytime' Datum='' Lat='$gpslatitude'
Lon='$gpslongitude'/>

And to separate the date and time and get the date format that you use,
I have created two user-defined tags, "MyDate" and "MyTime",
using the following
config
file:


- Phil

[Originally posted by dbrb2 on 2008-02-28 14:56:18-08]

Wow - that was both a very rapid and a very helpful reponse - I'll try it this evening and post here with the results!

Cheers,

Ben

[Originally posted by tistre on 2008-02-28 20:55:17-08]

Hi,

thanks for the great work on ExifTool!

Just a short question - a built-in option to do a full image metadata dump to XML would be great for us "non-Perlers"; any plans for adding something like this to ExifTool? Or do you know of an existing implementation?

I've had a quick look at Mediator (from http://openlab.savonia-amk.fi/mediapilotti/) which seems to be based on ExifTool, but it displays a lot less metadata than ExifTool does when invoked directly.

I'm not sure, but I think simply wrapping ExifTool output in XML tags wouldn't be sufficient since some character set magic would have to be applied? (I can imagine IPTC info in the Mac character set mixed with UTF-8 in XMP... or is there already a safe way to guarantee clean UTF-8 output of all metadata?)

Thanks again,

Tim Strehle
http://www.strehle.de/tim/

[Originally posted by exiftool on 2008-02-29 11:58:26-08]

Hi Tim,

The character set wouldn't be a problem because exiftool outputs
everything in UTF8 by default.  The problem would be deciding on
an XML format that would be most useful.  If you have any ideas
here, I would like to here them.

- Phil

[Originally posted by tistre on 2008-03-03 20:17:07-08]

Hi Phil,

thanks for the quick reply!

>  The problem would be deciding on an XML format that would be most useful.

Good question - we're currently generating (using the native PHP functions) a home-grown XML format containing all the metadata we've been able to extract. It's not beautiful, I'm not proud of it, but it's better than nothing :-) Here's an example: http://www.strehle.de/tim/metadata.xml (generated from the image http://www.strehle.de/tim/goettingen_maciptc.jpg).

Seems like Oracle invented their own Metadata Schemas - see http://download.oracle.com/docs/cd/B28359_01/appdev.111/b28414/ap_xmlschms.htm#AIVUG65000. XSD is hard to read, not sure whether it's a good XML format...

I don't know much about XMP, but I thought their aim was to be able to incorporate all other metadata formats. So it should be possible to output some XMP dialect (although I'm not a fan of RDF). Maybe inventing your own simple format that matches your internal data structures is the best way to go?

> The character set wouldn't be a problem because exiftool outputs everything in UTF8 by default.

It's great to learn that exiftool is all-UTF-8 by default. There may still be issues with character sets; my sample JPEG file contains metadata partly in UTF-8 and partly in Mac Roman (check the last name of the photographer, Swen P.) and we had to add some heuristics to detect Mac IPTC data and properly convert it to UTF-8. (Does exiftool already contain such heuristics?)

By the way - you probably have a large collection of sample image files with all sorts of metadata to test exiftool. Are they available, or do you know of any other publicly available set of files for testing metadata extraction and embedding? (All I have is the Adobe XMP SDK sample files and a couple of interesting images collected from customer sites over the years.)

Regards, Tim

[Originally posted by exiftool on 2008-03-03 21:35:58-08]

Hi Tim,

Thanks for the XML links.  I'll read them when I get a chance and think
about this some more.

OK, yes, character handling can be a problem in IPTC.  I outline how
exiftool handles the character codings in
FAQ
number 10.

Yes, I have quite a collection of meta information, but the only files I
currently make public are the samples in the t/images directory of
the full distribution, and my
JPEG
sample images (but these are straight from the camera and in general
don't contain IPTC or XMP).

- Phil

[Originally posted by tistre on 2009-02-26 08:37:57-08]

Hi Phil,

a colleague just showed me that XML output support (-X) has been added to ExifTool in October 2008.

Thanks a lot, this is a great feature that will make integration so much easier!

Kind regards,

Tim