Some pixels strips like APA102 have a clock line, WS2812B (neopixels) don’t, and need exact timing.

• Some pixels strips like APA102 have a clock line, WS2812B (neopixels) don’t, and need exact timing.
• Either you do precise bit banging with interrupts
• Or some chips allow you to do DMA with a coprocessor while the main CPU is free to do other work
• Teensy can use its versatile serial port driver to do DMA https://www.pjrc.com/non-blocking-ws2812-led-library/
• ESP8266 can use DMA by abusing its I2S driver https://github.com/JoDaNl/esp8266_ws2812_i2s/
• ESP32 has an 8 channel RMT driver to do general IO like IR or Neopixels
• With DMA output, doing IR with interrupts is a non issue.
• https://github.com/marcmerlin/Neopixel-IR is a multi-driver example

Extra points: Neopixel DMA