Ok, so I know the YM2413 isn't strictly Genesis, being a Japanese SMS-only chip for the most part. I asked this question
on SMS Power but so far have gotten no response, probably due to a huge likelihood that the intersection of devs with
any YM2413 knowledge, devs with C/C++ knowledge, and devs with JavaScript knowledge is only...myself.
I'm almost done with porting the MAME/SMSPlus/Genesis Plus GX YM2413 (ym2413.c rather than emu2413.c) to
my web VGM player but it sounds all wrong (ignore me muting all YM2413 channels except channel 1 for now). The songs to listen to are in the "test" playlist:
- test-ym2413.vgm (an A440 played with the "guitar" instrument for 2/10ths of a second)
- BIOS.vgm (the SMS Space Harrier BIOS).
- Green Hills Zone OPLL.vgm (ValleyBell's OPLL cover); GHZ sounds particularly incorrect.
MaliceX/DJTuBig pointed out over IRC it might have to do with FNUM calculation, but I went over that bit a couple of times and couldn't tell if it was the problem area or not. It also looks like setting instrument values is borked, but I don't know how to fix it. I have an update to the script that's still bad but not quite as much, but keep in mind I'm leaving only channel 1 active on YM2413 during development phase. My complete lack of familiarity with the YM2413 vs the YM2612 is very apparent in this process
Please help me figure out what needs to be fixed so I can move on to adding unzip, writing a basic sampler script to handle YM2612 DAC, and finalizing VGM 1.50 spec on the web player, thanks!