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Plugin Development and .lrprev files

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Bentron2000

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Hi All,

I am building a plugin that would like to take advantage of the biggest preview available in the lightroom cache.
I have played with a few different tools that read previews from these files - and the largest most of them can pull out is 'level_5'.
A manual inspection of a .lrprev file would seem to indicate that there is additional preview data at 'level_6' and 'level_7' in there.

Has anyone had any luck accessing these larger previews?

Ideally I'm seeking some means by which I can parse out these previews as separate files/streams for use in my plugin. i.e. details of the internal structure of these files.

- Feel free to offer wisdom in whichever language you like to work in - I've inspected partial solutions in C/C++, Python and Lua. e.g.
- Perhaps the larger versions are not in JPEG/JFIF format and that's why they don't parse out as easily?
- I'd prefer to work only with the .lrprev files rather than have to access the sqlite db - it would seem superfluous considering the UUID can be retrieved from the SDK and the .lrdata is structured using a tree built from the first 4 characters of it.

Any help appreciated!

Thanks!

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The program I wrote recently for another member is NOT a plugin, but pulls the largest available from the file.

It was a very quick and dirty program just for a special purpose so don't expect a lot of documentation: GitHub - Linwood-F/DumpJPGs

I can't recall how many levels they build, but once you pull them out you should be able to see how they are labeled, obviously the 1:1 is going to be the largest (at least I assume so).

I'm assuming you know that previews come and go, there may be none, they may be there and not be current, etc.

The previews do NOT have orientation and similar info, the SQLite DB provides that, and the catalog ties back to the original file names. The previews have no real names, no metadata at all, just image data.
 
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