Play MIDI as MIDI SPU?

Slaimus · July 28th, 2001

Why don't SPUs play the MIDI sequences as a MIDI rather than trying to emulate the MIDI synth on the PSX?
It would have less CPU overhead, no music skipping/pausing, and eliminate complicated coding to emulate the instruments properly.
People can then use soundfonts or DLS that work best, or use the Yamaha XG-MIDI softsyn which has almost exact tone generation compared to the PSX's Yamaha sound chip.

Zster · July 28th, 2001

I've heard this mentioned before and from what I can tell there's no specified format for Midi on the PSX. Each programming team comes up with their own particular routine for coding a music player. This routine is emulated by the emulator. Like the SNES where you basically had to dump the entire contents of the music ram to save the tune. Which leads me to ask why we haven't something similar for Epsxe savestates? On the other hand even if the SPU author were able to use MIDI there would be far more of a delay before the sound than there is now. You could try program to sound card hardware directly but that's damn difficult and wouldn't be very compatible. (I dream of 8 splin interpolation in hardware)

AdmiralKirk · July 28th, 2001

If memory serves, PSX uses XG for its midi syth, only Yamaha cards support this in hardware, and the software syths are SLOW!!!!. Personaly im very impressed with what the current sound plugins can do.

takwu · July 29th, 2001

this might be irrelevent, but...
VGS sounds perfect. Heck, even bleem! sounds pretty close to perfect. Neither does that MIDI thing you're talking about. HMMMmmm...

**Lewpy** · July 29th, 2001

The PSX does not have a hardware midi engine. So, you can't just load up a MIDI file, send it to a hardware chip, and say "play that".
What it does have is a 24-voice mixing system, with 512kb of dedicated sample (and working-set) memory. In a lot of ways, this is similar to the Gravis Ultrasound cards, and the Creative AWE32. But the PSX uses ADPCM compressed samples, has ADSR envelope filtering per voice, reverb mixing per voice, and the ability to pass the output of one voice as the frequency modulator on the next voice.
So, when a PSX plays music in the SPU, it is very similar to a PC/Amiga playing back a .MOD/.S3M/.XM/.IT file, where the sample data must be downloaded for playback, plus the program is responsible for all voice management (i.e. playback).
The reproduction of this sound in the emulator is therefore highly dependent on the accuracy of the emulation of the SPU, and it's interactions with the rest of the system (i.e. interrupt generation to the CPU, etc.)

cairey · July 29th, 2001

Trackers rock!

July 28th, 2001	#1 (permalink)
Slaimus Registered User Join Date: Jun 2001 Location: Maryland Posts: 21	Play MIDI as MIDI SPU? Why don't SPUs play the MIDI sequences as a MIDI rather than trying to emulate the MIDI synth on the PSX? It would have less CPU overhead, no music skipping/pausing, and eliminate complicated coding to emulate the instruments properly. People can then use soundfonts or DLS that work best, or use the Yamaha XG-MIDI softsyn which has almost exact tone generation compared to the PSX's Yamaha sound chip. __________________ My system rigs - http://www.anandtech.com/myanandtech.html?member=33624 Currently promoting the anime: Akihabara Denno Gumi

July 28th, 2001	#3 (permalink)
AdmiralKirk Registered User Join Date: Jul 2001 Posts: 48	If memory serves, PSX uses XG for its midi syth, only Yamaha cards support this in hardware, and the software syths are SLOW!!!!. Personaly im very impressed with what the current sound plugins can do. __________________ WHAT!?!?! No soda.... Your saten arnt you....

July 29th, 2001	#6 (permalink)
cairey Registered User Join Date: May 2001 Location: England Posts: 215	Trackers rock! __________________ http://go.to/cairey - My Home Page

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July 28th, 2001	#2 (permalink)
Zster Registered User Join Date: Apr 2001 Posts: 47	I've heard this mentioned before and from what I can tell there's no specified format for Midi on the PSX. Each programming team comes up with their own particular routine for coding a music player. This routine is emulated by the emulator. Like the SNES where you basically had to dump the entire contents of the music ram to save the tune. Which leads me to ask why we haven't something similar for Epsxe savestates? On the other hand even if the SPU author were able to use MIDI there would be far more of a delay before the sound than there is now. You could try program to sound card hardware directly but that's damn difficult and wouldn't be very compatible. (I dream of 8 splin interpolation in hardware)

July 29th, 2001	#4 (permalink)
takwu previous extinction Join Date: Apr 2001 Location: BC, Canada Posts: 1,855	this might be irrelevent, but... VGS sounds perfect. Heck, even bleem! sounds pretty close to perfect. Neither does that MIDI thing you're talking about. HMMMmmm...

July 29th, 2001	#5 (permalink)
Lewpy Emu author Join Date: Apr 2001 Location: Southern England Posts: 519	The PSX does not have a hardware midi engine. So, you can't just load up a MIDI file, send it to a hardware chip, and say "play that". What it does have is a 24-voice mixing system, with 512kb of dedicated sample (and working-set) memory. In a lot of ways, this is similar to the Gravis Ultrasound cards, and the Creative AWE32. But the PSX uses ADPCM compressed samples, has ADSR envelope filtering per voice, reverb mixing per voice, and the ability to pass the output of one voice as the frequency modulator on the next voice. So, when a PSX plays music in the SPU, it is very similar to a PC/Amiga playing back a .MOD/.S3M/.XM/.IT file, where the sample data must be downloaded for playback, plus the program is responsible for all voice management (i.e. playback). The reproduction of this sound in the emulator is therefore highly dependent on the accuracy of the emulation of the SPU, and it's interactions with the rest of the system (i.e. interrupt generation to the CPU, etc.)