Lightroom Classic: JPEG Mini standalone is multicore but as a LR plugin, it's constrained to one core

The JPEG Mini plugin manufacturer, Beamr Imaging Ltd, did respond that their hands are tied by the LR software. It's up to Adobe to allow this plugin to access multiple threads. It's insane the difference in export time between EXPORT+PLUGIN vs EXPORT then pull into desktop JPEG mini app. 50% time reduction. 

See if you can get Beamr Imaging to post directly here with their views on how this affects their plugin. 

I observed the same issue, investigated and contact them as well.
I got the same response - "it is impossible because of lightroom".

I think they are wrong and it an problem with their plugin implementation and not LightRoom.

From my analysis is seems that the problem is probably because they are using the suggested loop code from LR manual for "processRenderedPhotos()" which is processing one picture at the time.
The pluging call JPGEGminiTool one jpeg at the time and wait for it to complete before moving to the next one:
The call command is somethng like: "JPEGminiTool -action process -path E:\Lightroom Export\SM5D7315.jpg -result AppData\Local\Temp\LR-3"

That is why it use one CPU at the time (one CPU per picutre and one picture at the time)

I ask if they have a way to call JPEGminiPro.exe with a list of files to process.
They said no !
If they had such way (and they probably should) you can save tones of time by doing the following :
Dump the list of exported files to a text file then call JPEGminiTool or JPEGminiPro to process all the files and it would use multi-core.
For example:
Use  "Jeffrey’s “Run Any Command” Lightroom Export Plugin"
with the command:
"JPEGminiPro.exe -files {MANIFEST}"

But they don't provide a way to call JPEGminiPro with command prompt option to send the files.

There might be a way to automatic the process of open JPEGminiPro and drag the files from the "{MANIFEST}" to JPEGminiPro but I never done that before so I didn't manage to do it yet.

From my analysis, it seems that the problem is probably because they are using the suggested loop code from LR manual for "processRenderedPhotos()" which is processing one picture at the time.
The plugin call JPGEGminiTool one jpeg at the time and wait for it to complete before moving to the next one:
The call command is something like: "JPEGminiTool -action process -path E:\Lightroom Export\SM5D7315.jpg -result AppData\Local\Temp\LR-3"

If JPEGmini would have a command line option to get a list of files to process that won't be the case.
You could use "Jeffrey’s “Run Any Command” Lightroom Export Plugin"
with a command like: "JPEGminiPro.exe -files {MANIFEST}"
and the process of all the files would be done multi-process just like dragging multi-files to JPEGmini.


It is solve-able by doing different implementation - don't do one picture at the time if your tool knows to run in multi-core.
Collect the names of all the processed jpegs, export the list once everything else done and do one call to your tool with all the jpegs which would run multi-core.


BTW I made the experiment with I9 9900K and 220 RAW files and the times are:
LR + JPEGmini Plugin: Total export time: 15 minutes and 59 seconds
LR + JPEGminiPro : Total time: 4 minutes and 51 seconds. (LR: 3 minutes and 36 seconds. + JPEGminiPro: 1 minute and 15 seconds. )

I agree with your analysis. Have you communicated this to JPEGmini support?

I first contact them asking if they are aware of the slowness in LR plugin compare to the JPEGminiPro tool and the answer was they are aware of it and said “Adobe is 1 core processing making the process slower”.

When I asked the support if JPEGminiPro support command line to pass multiple files the answer was NO.

When I suggested the change in the LR plugin I didn’t get a response.

 

BTW I found this AppleScript that might help automate the process without the JPEGmini support:
https://github.com/JamieMason/ImageOptim-CLI/blob/master/osascript/run-jpegmini.applescript

The plugin's source code is uncompiled. It would be straightforward for a plugin developer to modify it to run n concurrent instances of the program JPEGminiTool, rather than 1 at a time. A few of my plugins use similar concurrency.