[FEATURE] SNDH plugin for Atari ST muzik with psgplay.

[cederom]

Hello world :-)

Quite late but I just found out the SNDH Archive [1] with all muzik from Atari ST :-) PSGplay [2] is the open-source player that I just compiled on my FreeBSD box and plays them nice. It can be compiled as library too and probably a plugin for OCP :-)

[1] https://sndh.atari.org/
[2] https://github.com/frno7/psgplay

[mywave82]

Tiny bit related to ym files, which are just register-dumps sampled after the VSYNC interrupts.

[mywave82]

Implemented via caeb344.

[cederom]

WOOHA!! CONGRATZ AND BIG THANK YOU!!! =) <3

[cederom]

Just a confirmation that builds and works fine on FreeBSD from git master :-)

Please let me know when it jumps into a release I will update the FreeBSD's OCP port :-)

[cederom]

The sound is a bit overloaded though.. maybe @frno7 can help? =)

[frno7]

The sound is a bit overloaded though.. maybe @frno7 can help? =)

Does OCP (somehow) sound different from the psgplay command?

[cederom]

Thank you @frno7 :-) It seems that standalone psgplay and OCP bundled version sound the same. But if you compare sound quality with other OCP input formats at first glance it seems that volume is too high thus overload distortions. However lowering the OCP output volume does not help. Maybe some sort of internal maximum volume in psgplay is possible?

This can be observed in some louder tunes (i.e. Dubmood) while some calm tunes (i.e. Tao) play mostly okay or the problems seem the same. Spectrum analyzer helps in visual representation here.

You can build git master and try yourself. There is a MODLAND archive built-in to the OCP so you can just fetch the list and have access to a tons of various music from various platforms. SNDH is added to the list. You can compare that with AdLib, YM, or Video Game Music / Sega Megadrive :-)

In order to run OCP that was built with ./configure --prefix=$HOME/.local I had to add export LD_PRELOAD="/usr/local/lib/libiconv.so:$HOME/.local/lib/ocp/libocp.so" before launch from $HOME/.local/bin/ocp :-)

[frno7]

Would you be able to indicate specific tunes that are problematic? Dubmood and Tao have made quite a few!

For example, would you say that the tune Tao/Do_Things/do_things_Intro.sndh by Tao is overloaded?

[mywave82]

Did a quick test on a couple of files (including Tao - do things Intro.sndh mentioned) with the diskwriter in OCP, and fileoutput from psgplay. I believe they are identical.

@cederom Do you have a problematic file?

[cederom]

Thank you @mywave82. I have uploaded some modules and wav renders here https://www.tomek.cedro.info/files/tmp/ocp-sndh-20260328/.

Some tunes from SNDH compared to other formats seems to sound kinda harsh, overloaded, not soft to the ear. Both in ocp and psgplay, but in ocp you can switch o other formats easily and see the difference. I don't know if this is just the tune/format/platform specific?

[frno7]

Dubmood/Galax.sndh, Dubmood/Hybridworms_Funky_Stars.sndh and Tao/Songs_That_Make_You_Go_Mmh/Commando_Hiscore_digi.sndh sound pretty much as expected to me!

@cederom, if you really want something ‘overloaded’ and properly crunchy, try Mad_Max/Demos/So_Watt/S_O_S.sndh, especially between 01:16 and 01:40. Pump up the volume. :-)

In fact, S_O_S.sndh had a bug report (frno7/psgplay#18) that its bass was ‘too poor’. After fixing that, and adding the empiric mixing tables, default now, it was reportedly fixed (frno7/psgplay#18 (comment)). How does that tune sound to you?

Note: The --psg-mix=linear option will decrunch the sound a bit, but actually sound significantly more gentle than real Atari ST hardware. As a matter of taste, though, you might prefer it, to the wild stuff?

[mywave82]

Remaining before release of new version is option to select between linear and emperic mixer.

These part of the bug report probably should be moved to psgplay.

One though without looking intobyour mixing option. The real hardware, how fast is it able to push voltage changes/transients? There are always fall/rise time, but is it within the audiable range or not.

[frno7]

Remaining before release of new version is option to select between linear and emperic mixer.

Call psgplay_digital_to_stereo_cb() with either psgplay_digital_to_stereo_empiric (default) or psgplay_digital_to_stereo_linear as argument.

Other mixing enhancements are available too, for example stereo mixing, which is especially nice with headphones.

One though without looking intobyour mixing option. The real hardware, how fast is it able to push voltage changes/transients? There are always fall/rise time, but is it within the audiable range or not.

The PSG channel outputs are clocked at about 250 kHz, so well beyond any human hearing range. Real Atari ST hardware has something resembling a current steering resistor ladder network with not-so-good-quality components, hence the nonlinear empiric mixer model. And then buzzing from ground loop noise of low-quality power supplies etc. (which is not modeled by PSG play).

Note, though, that some tunes with sampling effects assume and are tuned for the nonlinear (empiric) mixer of real hardware.