ws2812 flicker at random times about esp8266_artnetnode_v2 HOT 2 OPEN

Have you considered using the I2S hardware to drive WS2812 in the background instead of bitbanging it?
Have a look at https://github.com/TheSeven/esp8266firmware/tree/master/src/device/ws2811 for an example.
Some of that code was written by me (feel free to use that), but the I2S interface setup etc. was cherrypicked from random places all over the internet - not sure where exactly the idea originates from. It's been floating around for a while.
Once I get around to getting this project set up on physical hardware (sorry, I'm quite busy lately as well), I might have a go at implanting that into this project.

from esp8266_artnetnode_v2.

I needed multiple stripes per esp so I2S wasn't an option.

The reason for the flickering is an added 6µs by the wifi IRQ. However this wont be disabled by calling RSIL as it is managed by the NMI.
Therefore you also have to mask the non-maskable interrupt to get consistent timing.
Luckily some wise guys found out how: https://www.esp8266.com/viewtopic.php?f=9&t=3979&start=20
After some trial and error i got it to work, it a'int pretty yet but flicker free at last.
https://gist.github.com/scamiv/b931b307afaead5a0f43e6eb2bc57e08

Edit: This is a hack, not a fix. The proper way would probably be to actually use the nmi to shedule our packets.

from esp8266_artnetnode_v2.