Atomic Skull wrote on 2024-03-22, 06:27:Well yes you'd want a steaming DAC for that. But as far as games programming is concerned if OPN had been the basis of PC sound […]
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Tiido wrote on 2024-03-19, 22:44:
The main issue with these ADPCM samples is that they come out of an external memory, which you cannot easily update. Easily here means to play back a WAV file or some other type of data stream. There is no DMA mechanism or anything and the keyhole interface to update that sample memory through the chip is very slow so it will take a lot of CPU power just to send the data stream, and even more to compress it to Yamaha specific ADPCM format in case of wanting to play multiple samples simultaneously such as what a game like Doom might do.
Well yes you'd want a steaming DAC for that. But as far as games programming is concerned if OPN had been the basis of PC sound cards instead of OPL then the way PC games approached sound would have been different anyway. OPN was widely used in Japanese PCs for example and they used it quite successfully. In that case game sound drivers would upload samples to the OPN's external memory ahead of time and the games would be designed around this. And 128k or 256k isn't as small as it sounds when you consider that ADPCM is 4 bits per sample. I'm not talking about a world where OPN and OPL coexisted I'm talking about a world where the Adlib went extinct alongside the Creative Game Blaster and IBM Music Feature Card and OPN based sound cards ruled MSDOS PC games. A YM2203 based card would have been much less expensive than the Adlib and might have been able to succeed based on the much lower cost (and assuming game developers supported it so marketing would have been important as well.) Adlib was imo way too focused on PC music and OPL on MSDOS succeeded mostly because it was the default.
Lack of a streaming DAC sounds like a deal breaker to us but for the majority of PC gamers back in the way it was a niche feature. Most people weren't into tracker music or anything like that they just wanted a card that would make music for their PC games.
But if you really did want a streaming DAC the best way would probably be to replace the OPNs companion DAC with something that could combine the audio stream from the OPN with a DMAed steaming audio sample. If youy could convince Yamaha there was money in it they might even have be willing to design something for that. If not there are other ways you could have added the stream from the OPN and the streaming DAC together before sending it to the companion DAC.
I am intimately familiar with most Yamaha FM chips, in terms of making music with them, writing software to utilize them, using them in my own custom hardware and also emulating them. I am very well aware how the chips can be used in every conceivable way pretty much (but I am most familiar with OPN family). It would have certainly been interesting to see a 4op chip be standard in PC world but I don't think YM2203 or 2608 would have been it, particularly the latter with its external memory requirements and much less 2610(B) which needs two kinds even (although later NeoGeo games used a chip that could join the two sound buses into one so single memory could be used for both types), not in the time when memory was still very expensive. The few sound channels were definitely gonna be a limiting factor as far as 2203 goes, it would not be able to compete with OPL2 or OPL2+CMS... I would say you really want the 6 channel chips and if there was gonna be one it was gonna be 2612/3438 instead of 2608 or 2610, but even then I don't see almost any non-japanese composer make good use of it.
You can see this on Mega Drive/Genesis games, most of the actually good sounding games were all japanese ones and vast majority of the western made games had pretty poor music although not always poor compositions. There were a few composers who really could make the chip sing like Matt Furniss but in general it seems that people didn't know how to actually use these chips or perhaps even cared... Even OPL2/3 can be made to produce excellent sound, stuff that OPN or OPM would really struggle to do due to less channels but that's not really what was done when these chips were still relevant either so I am really not sure if a different chip would have made any real difference in what we got musicwise anyway... Potential certainly would change but all that potential seems to always get utilized after the fact, this guy's OPL3 stuff is basically undoable on OPN/M family for example : https://www.modules.pl/index.php?id=modules&aid=1691
I very much meant streaming, a DMA based method will be necessary for that for sure so you could sort of end up with SB deluxe, depending on what kind of FM chip was there 🤣. Samples were the thing that really mattered it seems, and sooner or later the limited memory of 2608 etc. would have been a bottleneck, which you were not going to having with a stream device. That is probably one reason why PC sound cards remained quite boring compared to stuff you saw in some of the other computers etc and perhaps why all those other computers ended up dying out in the end, as sad as it may be...
As far as OPL4 goes, I think it came to the scene too late and probably was too expensive too. It also could not use DRAM (although there's reference to OPL4D chip that could but I have never seen one in the wild and no documentation of it seems to exist either), only SRAM or ROM and that makes it immediately unviable by the time it came around. Yamaha SW20PC card has a 128KB SRAM on it, but you cannot do a whole lot with that little memory, not in context of sound effects and especially when they had no compression at all. If it was around in like 1990 then perhaps it could have made some difference but not in 1995 where games already were using many hundreds of KB for sound data. You also cannot actually update the sound memory on the card without turning off all sound generation, the sound rendering needs to be disabled before the RAM/ROM bus becomes available so it is basically not possible to update samples on the fly, definitely not when music has to play at the same time...
The MSX Moonsound expansion seems to have cost 399 or 499NLG in 1995, I wonder much money was that...