It came to the attention of CD-i member Retrostuff that in a CD-i manual there is one page dedicated to other entries of 'The Private Lesson Series' like Jazz and Rock Guitar, mentioning 'EZ Play Piano featuring "some great general MIDI features". CD-i and MIDI sound do not generally go along together. cdifan confirms this: "Interesting...
The Red book supports inclusion of MIDI in the subcode channels but I
have never seen it on CD-i. Would probably need some kind of adapter for
the serial port anyway." - While we've never seen EZ Play Piano, we do know a title named 'EZ Play Keyboard', which might be the same title, but we have never seen a real copy of it (this is from a private collection)
"The question is, has this been released and under what title? If it
ever turns up, we could have a look at the features. I had a look at the
"Private Lesson Series" (Reihe Privatuntericht, Serie Privelessen,
etc.) and found only the guitars (Jazz, Rock, Classical) and the rhythm
title - renamed to "Rhythm Maker"." It would be an interesting idea to
play a cd+midi on the cd-i and plug a midi sound module in it. The Green
Book mentions this about MIDI:
That means that this feature is not included in Balboa or MediaMogul either. Unless, some publisher developed a custom driver. It reads as that it's an option for OS-9, that it's a custom module they (could) supply, but it also needs addtional hardware. Perhaps they just used the serial port for using MIDI I/O. (but MIDI uses a special bitrate and the serial port needs to support that. It would be interesting to check if there's any activity in the serial port when this CD-i title (EZ Play Piano) is played. But it would need a specific driver, as Retrostuff suggests: "See http://www.icdia.co.uk/faq/cdifaq5.html#5.15 CD-MIDI is a CD-Audio disc with MIDI (Musical Instrument Digital Interface) information in the subcode channels. This allows for MIDI-devices like synthesizers to play along with the music on the CD. The applications of CD-MIDI are very rare. The audio of a CD-MIDI disc can be played on any CD-player, including CD-i players."
[Thanks, Retrostuff, cdifan, vvs]