Play audio on an ESP32 or an Arduino
Base64 has nothing to do with audio. It is merely a way of encapsulating binary data into ASCII text so that it can safely be included in text-based structures like JSON, or transmitted over a text-based communication channel.
There is no library to &quot;play&quot; base64 simply because base64 is not something you play.
First you decode the base64 text into raw 8-bit binary. It's then that data that you play through whatever library is most suitable for your hardware.
For example on the ESP32 you have the function base64_decode() available. You can read up on how to use it in this tutorial.