CGB MP3 players

Discussion of programming and development for the original Game Boy and Game Boy Color.
Post Reply
pikachu64
Posts: 6
Joined: Tue Feb 06, 2018 5:32 pm
Location: Upstate NY, USA

CGB MP3 players

Post by pikachu64 »

So i've been looking into driving high quality audio with the Gameboy Color. I did some searching and stumbled upon the SongPro™ MP3 player for CGB. I was surprised that such a thing exists as I did not expect CGB to be capable of audio output approaching 44.1kHz * 16-bit * 2. The SongPro is akin to the official Nintendo PLAY-YAN for Gameboy Advance/SP and PLAY-YAN Micro for Game Boy Micro, also known as Nintendo MP3 Player.

Unlike the Play-Yan, the SongPro seems virtually impossible to get a hold of. Here are some articles I found on it:

https://www.ign.com/articles/2001/01/10 ... -the-beats
https://www.retrothing.com/2006/04/songpro_mp3_pla.html (Includes picture)
https://www.myce.com/news/Songpro-makes ... ayer-4095/

Without getting a hold of the cartridge or seeing footage it's impossible to say what its capabilities really are. Does anyone have one or have any thoughts on how it's implemented?
tepples
Posts: 22705
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Re: CGB MP3 players

Post by tepples »

All the decoding is done on the cartridge.
nocash
Posts: 1405
Joined: Fri Feb 24, 2012 12:09 pm
Contact:

Re: CGB MP3 players

Post by nocash »

I think so, too. The gameboy hardware is probably mostly used as "power supply" for the mp3 player, and apparently also for button input and screen output. It doesn't look so useful, the main motivation might be that "it is for the gameboy", if that is a priority when buying things.
For the audio, the cartridge slot has an external audio input, but it's mono, and I don't know if GBA is supporting that, too. Anyways, it might work for passing audio to the internal speaker. And I would expect that the cartridge has its own headphone socket for external stereo audio output.
pikachu64
Posts: 6
Joined: Tue Feb 06, 2018 5:32 pm
Location: Upstate NY, USA

Re: CGB MP3 players

Post by pikachu64 »

Thanks for the replies. I read the following on GB/C sound hardware:

- http://gbdev.gg8.se/wiki/articles/Gameb ... d_hardware
- https://problemkaputt.de/pandocs.htm

Are there any different resources that talk specifically about driving stereo audio (headphone jack output)? I'm interested in seeing what can be produced with the standard 4 (2 x 4?) channels and also Vin, without any microprocessor on-cartridge.
tepples
Posts: 22705
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Re: CGB MP3 players

Post by tepples »

By turning on all DACs and bit-banging the volume register, you can achieve 3-bit-per-channel stereo audio output. But you need some way to generate those 3 bits at an acceptable speed on a 2.1 MHz CPU with no multiply. It's not like GBA where you have 16.8 MHz and a fast multiply with which to decompress cosine transform or linear predictive codecs.
retro-collectables
Posts: 1
Joined: Tue Dec 01, 2020 5:38 am

Re: CGB MP3 players

Post by retro-collectables »

Hey, I have two Songpros. I am keeping one and selling the other, brand new, original boxed, and sealed. If interested check it out on my Etsy page.
https://www.etsy.com/listing/913889811/ ... ve_1&frs=1
Post Reply