retrieve brightness from squeezelite to drive an OLED screen

(cross post from "Linux / Unix" forum as the question is also "developer" oriented)

Hi,

Short question:
I'd like to retrieve player brightness value that should be sent by LMS to squeezelite via Slimproto "grfb" command.

Is there an easy way to do it without patching squeezelite?

If I finally add an handler for grfb commands in squeezelite/master/slimproto.c what would be the best way to interface squeezelite with a third party application?

• reusing visualization shared memory
• using stdout
• a file
• something else?

Long Story:
My two squeezebox 3 went dead recently (reboots in loop, mostly when playing audio... seemingly due to DAC capacitors old age wear) and I'm building a piCorePlayer from spare parts I had lying around.
I have a headless raspberry plugged to a SMSL AD18 digital AMP.

I'd like to drive a wide OLED display to emulate the original SB3 VFD:


Maybe by using some existing program like:
https://github.com/shunte88/LMSMonitor

Maybe by doing something simpler from scratch, just to display "now playing" and alarms (I was using my SB3 as an advanced alarm clock and I miss it terribly!)

So I want to retrieve player screen brightness from the server to mimic as much as possible the original SB3 behavior, to be able to use the brightness touch on the remote control, and use it to drive the OLED screen brightness.

Any hint welcome!
Robin