In here, we are using a PIC32MX250F128B with the Cytron SK1632 board. The WS2812's one and zero bits do look like PWM pulses with a different duty cycle, and the firmware replicates those by pushing the pulses into the WS2812's input by using DMA.
The custom effects are from WS2812FX library and Adafruit NeoPixel Library:
There is a small difference between WS2812 and the PL9823 - the color arrangement for WS2812 is GRB, while for PL9823 is RGB.
Cytron's SK1632 board: https://www.cytron.io/p-sk1632