Faster cache file generation by extracting embedded jpgs - worthwhile?

[ubacher]

Generating cache files from RAW files via the windows codecs takes a long time.
As I understand it most RAW files have a jpg embedded and this can be extracted with
exiftool. I assume this would take a fraction of the time.

My question: Would it be worth doing this? It would probably have to be restricted to
the RAW files which are known to have good embedded jpgs. And there would be some loss
of universality. But the performance gain would be tremendous. And the effort achieving
this should not be large since there is already an interface with exiftool.

[Mario]

IMatch by default uses the embedded preview if it is larger than the minimum size specified by you under Edit > Preferences > Cache.



Press <F1> in this dialog for detailed info. Or just search the help for preview.  It's the second hit.

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[ubacher]

I checked my settings of the DNG converter and I had set the thumbnail size to MEDIUM. This will explain
why it takes so long to create the cache image. 

[Mario]

If the embedded preview in your DNG files is too small, IMatch falls back to extracting the full DNG. This takes between 1 and maybe 10 seconds, depending on which of the many DNG variants you use, the installed codec and overall system utilization. If interested, the log file tells you exactly how long it takes, if IMatch could use the preview etc.