An Anonymous Coward writes:
MP3 decoding was already free and got recently included in Fedora. But now, encoding is also free according to Fraunhofer Institute for Integrated Circuits IIS: "On April 23, 2017, Technicolor's mp3 licensing program for certain mp3 related patents and software of Technicolor and Fraunhofer IIS has been terminated." The Wikipedia MP3 article confirms that.
So, do you still use an MP3 library or have you switched to another format or means of listening to music such as (spying built-in) streaming services?
So what does all this have to do with whether it's viable to encode your music library with something other than MP3?
Your position was that the majority of compressed audio is decoded using a CPU with an MMU. I concur. However, if maximum quality is desired and the number of audio channels is large (5.1 surround, 7.1 surround, 22.2 surround) then the use of CPUs without MMU becomes increasingly cost effective.