So, I tried Infrared (IRremote.h) receiving on ESP32 with FastLED.
As expected, @Yves_BAZIN 's library does not support this because it requires turning off interrupts. His code will not even compile if FASTLED_ALLOW_INTERRUPTS is set to 1
The good news is that @Sam_Guyer 's code since it uses RMT, doesn’t need interrupts to be turned off.
The other good news it that the ESP32 code in IRRemote does not use RMT because I wrote it, and I didn’t have the time to figure out how to make RMT work, so it uses silly interrupts and just reads a pin. Little did I know that my laziness would save me later by allowing this to work using interrupts without RMT while RMT is being fully used to output to 8 lines of fastled at a time.
I also did a quick timing test and with @Sam_Guyer 's FastLED ESP32 driver, I still get 55fps for 4096 LEDs, which is more than enough.
Anyway, just reporting back that 8 way parallel output plus interrupt driven IRRemote works fine on ESP32
Come to think of it, I think an RMT based IR driver + @Yves_BAZIN interrupt driven 16 line parallel output, might work too, but I don’t have one I can try with, nor do I really need one for now.