Re: [openMSX-devel] LADSPA/SCC

[Maarten t. H. <ma...@tr...>]

On Sunday 06 July 2003 22:45, Joost Yervante Damad wrote:

> I'm currently working on LADSPA plugins based on the audio devices of
> openMSX.

Cool!

Would this be usable to create replayers for MSX formats later?

> Currently I have SCC working (single channel, since polyphony is done by
> the LADSPA-host). In order to test it in a
> more fun way then the simple Sine I coded, I'm looking for someone/where
> who made a collection of SCC samples with a name. If I can't find such a
> thing, I'll patch openMSX to dump SCC samples for me :)

I never looked into them, but I would expect SCC music editors such as SCC 
Musixx and SCC Blaster to include a instrument library. Or at least the 
ability to rip instruments from existing songs.

But since dumping from openMSX is easy, why not do that as well? You could 
write a console command for it. On real MSX, you can reset the MSX and then 
look inside the instrument memory areas to rip the instruments. I had a quick 
peek in the code, but openMSX doesn't seem to support this yet. Don't use a 
monitor program by the way, since reading one of the higher addresses in that 
256-byte area will trigger the wave form rotate/distortion feature. I always 
used good old BASIC.

You could also take a hex editor and look in some Konami ROM files. The wave 
forms are typically in a table one after another. They can be spotted if you 
have an eye for patterns.

In later games Konami seems to have a standard format for their "music page": 
at the 0x2000 (8K) boundary at which the page starts, there are three JPs in 
a row (C3 ll hh), with addresses in [0x6000..0x8000). If my memory is 
correct, there is a start song/effect, stop and the interrupt routine (not 
sure which order). In that same page you can find the instrument data.

Some tables I found:
Nemesis 2: 0x0000:8080
Nemesis 3: 0x0001:5B44
King's Valley 2 MSX2: 0x0000:92A0
Quarth: 0x0000:98DC

The page starting at offset 0x0000:8000 seems to be popular, for the 128K ROMs 
at least. And usually the instrument table is directly after a pointer table, 
which are easy to recognise because most of them are sorted, meaning a lot of 
equal high bytes in a row.

Bye,
		Maarten