BackgroundAudio is an Arduino library that lets sketches play MP3s, AACs, and WAVs on the Raspberry Pi Pico, Pico 2, and ESP32 with a very simple application level interface. Data is written to the playback object when available from the main application, and interrupts (IRQs) are used to generate data for I2S, PWMAudio, or Bluetooth A2DP in the background. The application only needs to provide data faster than it is decompressed. There is a source buffer that's managed by the playback routine, letting apps "fire and forget" for playback.