Limitations with MSX-Music

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By Giangiacomo Zaffini 2

Master (206)

Аватар пользователя Giangiacomo Zaffini 2

26-12-2019, 11:33

I recorded (-12dB peak circa) two out of three latest roms, out of television, an old SamSung LED LCD.

I used Panasonic FS-A1ST MSX turboR with MegaFlashROM SCC+ +SD, and Evistr digital voice recorder. No editing, clicks, noises and stuff, everything is there.

joou-fm3.wav

so3-fm3.wav

By DarkSchneider

Paladin (929)

Аватар пользователя DarkSchneider

26-12-2019, 13:37

sd_snatcher wrote:

I'm not sure about the sound limitations on the MSX-Music (OPLL).

From what I understand, you can only select one hardware sound or software variations of it for a full set of voices.
Is that it ?

But what about the drums then ?

As you asked for limitations of the MSX-Music and not only the YM2413, I believe you want to know about the entire standard.

Apart from the YM2413, there's the BIOS also. The MSX-Music BIOS a badly done hack off the MSX-Audio BIOS. So badly done that it can't even be considered a BIOS, since it does not implement the standard BIOS calls, implementing only the MSX-Basic functions and a small set of almost useless CALLs. It's mainly used as a detection pattern for the cartridge, since the YM2413 only was write-only.

Not so bad. It includes detection, initialization, built-in player (bad that ML player is only for BASIC), and writing registers not using direct ports (that is supposedly not allowed by the standard).

Quote:

Commercial business software should use the FM­BIOS when accessing the OPLL. Direct useof the I/O ports will not guarantee compatibility.

If want to use direct ports, probably the correcy way would be to look them into WRTOPL(4110H) function. Not sure why simply is not used the VDP.DR/VDP.DW MSX BIOS method, putting the ports used at somewhere as direct data numbers. Simple, clear and versatile.

By Grauw

Ascended (9071)

Аватар пользователя Grauw

27-12-2019, 01:37

Giangiacomo Zaffini 2 wrote:

I recorded (-12dB peak circa) two out of three latest roms, out of television, an old SamSung LED LCD.

I used Panasonic FS-A1ST MSX turboR with MegaFlashROM SCC+ +SD, and Evistr digital voice recorder. No editing, clicks, noises and stuff, everything is there.

joou-fm3.wav

so3-fm3.wav

Sounds a bit more muffled than on my TurboR GT, I guess thanks to the audiofix to the LPF circuit :).

Also yeah I get the same weird cut and loop after 2 minutes 15. That’s exactly at the 2 MB mark. I think there’s a bug with the MegaFlashROM SCC+ SD where it only supports ASCII16 ROMs up to 2 MB, despite the mapper supporting up to 4 MB and the MFR having 8 MB of FlashROM…

(That’s why I ordered a Carnivore2 the other day :).)

Manuel wrote:

Can you also make some videos of these examples playing on real hardware?

I will, but since watching a blank screen is a bit boring for a video I decided to add a little visualisation. Please stand by while I wrap that up, and also find a song which isn’t likely to cause me a copyright strike on Youtube like Shiina Ringo’s Kabukicho no Joou song probably will.

By DarkSchneider

Paladin (929)

Аватар пользователя DarkSchneider

27-12-2019, 12:55

Grauw wrote:
Manuel wrote:

Can you also make some videos of these examples playing on real hardware?

I will, but since watching a blank screen is a bit boring for a video I decided to add a little visualisation. Please stand by while I wrap that up, and also find a song which isn’t likely to cause me a copyright strike on Youtube like Shiina Ringo’s Kabukicho no Joou song probably will.

This one is there since 2012:
https://youtu.be/VxCJXbtG-VE
Or any other in the album:
https://www.youtube.com/playlist?list=PLirSddeMOYZ6H7yXWK8302AX4MNDhXORQ
Also you could use Vimeo, where usually don't drop videos.

By Grauw

Ascended (9071)

Аватар пользователя Grauw

30-12-2019, 22:43

Here’s a video for your enjoyment, captured straight from my MSX turboR (with audiofix):

http://www.grauw.nl/etc/msx/FMPCMPlayer.mp4

Also on Youtube, but with the second song removed since it got blocked for copyrighted music.

By Manuel

Ascended (16639)

Аватар пользователя Manuel

30-12-2019, 22:21

Great! By the way, is this the same trick that was used in PSG Sampler to play samples on YM2413?

By Grauw

Ascended (9071)

Аватар пользователя Grauw

30-12-2019, 22:55

Since you mentioned earlier that PSG Sampler uses the same method as those demos on Clubguide Magazine 3, then they too use the test register but that’s where the similarity ends. By setting certain values they managed to achieve a noisy 4-bit PCM that’s not very precise. My method gets near 8-bit PCM by precise control with the knowledge of the OPLL’s internals we have nowadays.

I did use those demos as a starting point for my method though.

By sdsnatcher73

Paladin (949)

Аватар пользователя sdsnatcher73

31-12-2019, 07:12

Cool stuff Grauw!

On a side note, what card/device do you use to capture the MSX audio and video?

By alexito

Hero (623)

Аватар пользователя alexito

31-12-2019, 08:40

Good job. Grauw. Very good achievement now we can create better demos or games. This technique on Turbo R can give us until two PCM channels if H-INT and the TIMER is used. I'm right?

By Giangiacomo Zaffini 2

Master (206)

Аватар пользователя Giangiacomo Zaffini 2

31-12-2019, 11:01

I think this is amazing. These techniques make MSX2+ closer to turboR feature-wise and some PCM is super useful for trackers and sounds FX.

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