Amazing that I haven’t come across this MML player before: http://mmltalks.appspot.com/
I used to program songs in MML on the MSX (the Music Macro cartridge YRM-104 also makes use of this syntax).
The MML Player is based on Flash’ SiON engine which actually is able to emulate all the CX5M’s soundchips: https://sites.google.com/site/sioncenter/example

just sayin’….