New Moonblaster 1.4 driver

I'm confused, wasn't MB already equiped with the equal-replay option? (or is that because I had implemented it myself in the FK version? hmm... me's gonna check)

disassembled source? afaik the source is provided on the original MB disk

aaah, we're talking the BASIC replayer here. aha, totally miz'd that. but wtil, that came without the eqplaythingy? hmmm. who needs basic anyway...

signed, your asm friend.

Yeah, we're the lazy bunch eh

With the asm replayer this is not supported. At 50hertz the music is clearly slower.
Am I missing something? I can't find any support for this in the code either.
Is this only for the basic replayer maybe ?

Conditionals in the assemby file:
;
; conditionals
;
withBIN: equ 0 ;1=include .bin header
withTurboR: equ 0 ;1=include TurboR supported code
; (pre-select and timing)
withMapper: equ 0 ;1=include Mapper supported code
;withMapper: equ 1 ;1=include Mapper supported code
withHook: equ 0 ;1=strmus will set the hook
;0=you will need to call musint
withFade: equ 1 ;1=include fade-out code

The withHook doesn't solve this. The withTurboR doesn't change things either....
Any idea?

Should music be written specifically for 50hertz ? And if so, how ? I don't see the option in Moonblaster to write specifically for 50hertz.

Well I can see how you can write music for 50 hertz.
Then when you play it back in 60 hertz just skip the music playback once every 6 frames.
But you would 'hear' that, and it wouldn't sound so nice....
Doesn't seem the best sollution, but if it's the only solution I'll take it

Indeed that's the simplest way to do it. Or compose for 60 Hz and call the replayer code twice every 5th frame, depending on which frequency you want to optimise for. This is the common solution and likely what BiFi did here. It will introduce a slight shuffle but I don't think the effect is super noticeable (but your ears may have a different opinion).

For the perfect solution, use line interrupts to create a 300 Hz timer, and then invoke the replayer every 5th or 6th interrupt depending on composition frequency (recommend 60 Hz in this case). I do this in VGMPlay (see LineTimer.asm); after each line interrupt increment the split line number by 52 (60 Hz) or 51 (50 Hz), and reset to 0 when it overflows. Now you've got a great 300 Hz timer with only a small inaudible imprecision of 0.2 ms.

It's not very complicated in principle, but for use with games of course downside is that 1. it may interfere with other splits that you use, possibly complicating your line split setup a bit, and 2. music interrupt handling can occur at various moments during the frame. That's why I recommend to compose for 60 Hz so that when playing on 60Hz it is always done once per frame at the exact same moment, while on 50 Hz it occurs roughly every 262 lines (out of 313) so at different parts of the frame and sometimes twice per frame (but you likely have spare CPU time then).

To clarify this method a bit further; to get an exact 300 Hz timer you need to generate an interrupt every 52.33 lines (3579545 / 300 Hz / 228 CPU cycles per line).

At 60 Hz there are 262 lines displayed per frame, which we want to divide in 5 parts. So if we increment the 8-bit line counter by 52 until it overflows, we get 5 interrupts on lines 0, 52, 104, 156 and 208.

At 50 Hz we want to divide its 313 lines in 6 parts, for which we use a little trick by incrementing the counter by 51; then we will get 6 interrupts on lines 0, 51, 102, 153, 204 and 255 before it overflows.

Refining this a bit further, in VGMPlay I actually need a 300 Hz timer, but if your music is authored for 60 Hz you don’t actually need all of those line interrupts, but only a fifth of them. If you would want to reduce the amount, at 60 Hz you could simply use the VBLANK interrupt, and at 50 Hz set line interrupts on the following sequence of lines: 0, 255, 204, 153, 102, 51.

Note that the line numbers are not exact multiples of 52.33, and neither are the 50 / 60 Hz display frequencies actually exact divisions of 300 Hz since they’re really 50.15 Hz and 59.92 Hz. So there is a small amount of error but it’s too small to notice, and it syncs up predictably to the frames which is good for games.

I want to add a volume control in the moonblaster-driver.
This way the user can balance the volumes (psg, msx-music and msx-audio).

But after 2 days of hacking in the code I haven't been succesful. There are barely any comments in the code, so it's extremely hard to figure out what's happening.

Is there anyone who has tried something like this themselves ?

The guys of Hegega did something like that. When pressing the i button in the replayer of Carbuncle Big Band you can control the volume of all channels.