mpg123 is an mp3 decoder/player. If you want to use it for playering, you need a guest environment with audio capability. Currently, audio capability is most easily provided by an emulator such as QEMU.
The bakeable binary will be available in
rumprun kvm -i -b ~/tosi.iso,/mp3 -g '-soundhw es1370' mpg123.bin -v -z -@ /mp3/allmp3.txt
tosi.iso contains mp3's along with a list of them)
rumprun kvm -i -I iftag,vioif,'-net user' -W iftag,inet,dhcp -g '-soundhw es1370' mpg123.bin -v 'http://10.0.0.10/test.mp3'
(tested working, but network configuration is left as an exercise to the reader.
if you want DNS, remember to provide a stub