I'm trying to create a script to regenerate full-size JPEG previews to all DNGs where it was not done upon the initial conversion. With a metadata explorer such as Perl's exiftool, I can extract the size of the previews and see whether they're full-size or not.
Now the interesting question is to replace the original DNG with the same but only the full-size JPEG preview regenerated. How can one do it with the Adobe DNG converter, preserving all the keywords and other metadata? Furthermore, how can it be done so the Lightroom will not notice anything?
Essentially, I'm trying to add another button to the Lightroom -- not just "Update DNG Preview," but "Update DNG preview where full-size is missing." Ideally, of course, we'd have "Update DNG Preview if obsolete," including obsolete as non-conforming to a given set of the desirable preview settings, such as its size.
In the very worst case, I'd have to program Mac GUI with AppleScript to find only the DNGs where the preview is not full-size via my Perl magic, then somehow select them all in the Lightroom and robo-click "Update DNG Preview and Metadata" for the selection -- but I'd really, really prefer to be able to do it from the command-line with the DNG converter itself. Possible?
Now the interesting question is to replace the original DNG with the same but only the full-size JPEG preview regenerated. How can one do it with the Adobe DNG converter, preserving all the keywords and other metadata? Furthermore, how can it be done so the Lightroom will not notice anything?
Essentially, I'm trying to add another button to the Lightroom -- not just "Update DNG Preview," but "Update DNG preview where full-size is missing." Ideally, of course, we'd have "Update DNG Preview if obsolete," including obsolete as non-conforming to a given set of the desirable preview settings, such as its size.
In the very worst case, I'd have to program Mac GUI with AppleScript to find only the DNGs where the preview is not full-size via my Perl magic, then somehow select them all in the Lightroom and robo-click "Update DNG Preview and Metadata" for the selection -- but I'd really, really prefer to be able to do it from the command-line with the DNG converter itself. Possible?