Author Topic: Exiftool Integration  (Read 212 times)

Offline EtMRS

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Exiftool Integration
« on: September 18, 2021, 09:38:46 AM »
Can exiftool be implemented inside Photo Mechanic ?
Why we need this tool ?
We invest in Photo Mechanic Plus because we need a place where all the knowledge about a picture is stored and we chose Photo Mechanic Plus (PMp).
Migration of the knowledge is not easy because :
- some metadata exists both in Exif, IPTC, XMP...
- some metadata are implemented inside the file, like makers data, others in a sidecar file (xmp or xml)
- Exif, IPTC, XMP evolves with time
- implementation of Exif, IPTC, XMP... is software dependent.
We do this migration using exiftool, a power command line tool to import/export/edit... metadata. And so, we can write rules to move metadata to be PMp compatible and new IPTC/XMP compatible.
We have 86k pictures as original and 40k pictures as derivatives. Exiftool does the job very well.

But sometimes, we discovers a particular case that was not resolved by the migration rules.
And PMp can't help. Example: Credit exists in Exif, IPTC and XMP. Which one to use? In the RAW file, credit metadata comes from camera in Exif. But 12 years later, and because of evolution, this metadata is outdated. And so, it's inconsistency between Credit from Exif and XMP.
And we can't solve it in PMp.
On the other hand, there are metadata you don't see in PMp. Or with other name (like the camera maker Exif metadata). How can we have a FULL overview of the metadata available ?

How to implement ?
Exiftool can work on a single file or in batch. Hereunder, we assume we work on a single file. If user selects more than 1 file, they are executed one by one.
Three types of job :
- metadata editing : Exiftool uses argument file (*.args) to define operation, one by one, like Write XMP-Credit in Exif-Credit, write ''(Empty)" in exif-copyright.... So, when users selects this feature, he must select a recipe (argument file) too.
- Export metadata : Two case : export a list of all metadata for selected file in text file format (*.txt). User need to specify implemented or sidecars metadata.
         Export Embedded metadata  --> XMP Sidecar or XML sidecar
- Import metadata : Sidecar metadata --> Embedded metadata.

XMP sidecars are very important as a metadata transport between pictures : example : you want that a TIFF derivative to be synchro with the RAW ? Easy and fast: copy the XMP sidecar from the RAW near the TIFF and ask Exiftool to import in TIFF.   
And XMP sidecars are very important too for metadata transfer between applications....

In summary, implementation of Exiftool in PMp can solve, easily and fast, particular issue with Metadata Management that PMp can't do.
« Last Edit: September 20, 2021, 01:08:31 PM by Kirk Baker »