[b50123e] OPL note cutoffs and other issues

[Csonicgo]

An unfortunate terrible reduction of quality of the OPL synth has taken place between the last version of zdoom, and the latest GZDoom. Notes that would be sustained just get cut off, some notes get cut off prematurely - even though I'm emulating 8 chips, I still get cutoffs with one voice and it's not even that complex in the first place.

https://www.doomworld.com/idgames/themes/xmas/doomxmas Play the doomxmus.wad in this zip, D_RUNNIN and D_STALKS, in gzdoom, and then play them in the last dev build of zdoom. It's like night and day. I would record it, but zdoom won't run on my Pi 3 at the moment. This also happens on my x64 and x32 linux boxes.

https://github.com/sneakernets/DMXOPL/releases/tag/v1.3 These issues arose as I was placing the final touches on this GENMIDI patch.

[wildweasel]

I'm noticing this as well, with D_STALKS in Back to Saturn X Episode 2, the "soundtrack" instrument in the background cuts off, leaving the song rather empty.

[Graf Zahl]

How does it sound in Chocolate Doom? I had to ditch the entire channel eviction logic and replace it due to the licensing issues. And this part was quite different in CD.

[Rachael]

I wonder if the issue may be with the parsing code, itself, because it is not just the OPL that suffers from what I have noticed.

Even with Fluidsynth it doesn't sound right, and for sure it sounds wrong on the Windows SW Synth backend, too - and, oddly enough, in the same places.

[Graf Zahl]

If it's audible on all MIDI synths I wonder if it's not an error in the actual music. I think if there was an error in the MUS player someone would have noticed already with some of Doom's own music.

[wildweasel]

I've confirmed BTSXE2's D_STALKS sounds fine in Chocolate Doom, for what that's worth.

[Rachael]

It seems like my particular issue is related to the actual sound card drivers, unfortunately. I rerouted the sound output to my USB-adapted headset, and it sounds much better there. The internal Realtek sound adapter I have is a piece of shit, anyway. I'll probably just use a permanent USB soundcard, instead. I'd hate to do that, but it at least fixes my midi issues.

[wildweasel]

Are comparison recordings still needed? I can see about taking some later today.

[Rachael]

They would be helpful.

[wildweasel]

Okay, here goes, here are some Picosong links that should play directly from your browser (or download if you so wish). Each of these recordings is trimmed to roughly the section of the song that exhibits the issue; the song once again is D_STALKS from btsx2_e2a/btsx_e2b.wad.

Firstly, the "control": Chocolate Doom version 2.2.1. Music is set up to "OPL (Adlib/SB)" in OPL3 mode. This is the song playing correctly, to my ears.

Secondly, GZDoom 3.0.1 using the "Sound System" device. On my system, the device in question is simply called "High Definition Audio Device"; it is the onboard audio from a Gigabyte motherboard. The driver is the default one Microsoft installed via Windows 10. The song plays correctly here as well, indicating it is not a problem with GZDoom's MUS/MIDI handler.

On to the "broken" ones: This one's GZDoom 3.0.1 on the OPL emulator, on its default settings: MAME OPL2 core with 2 chips and Full Stereo Panning enabled. The strings instrument that gives the song an atmospheric bass backing fades out and never comes back.

I had wondered if this was the fault of the OPL core I was using, so I took another recording with the DOSBox OPL3 core and the same settings: 2 chips and full panning enabled. Again, the string bass fades out and never comes back.

[Graf Zahl]

What about older ZDooms? The least I need to know is if this is an issue of removing the MUSLIB code or something in the MIDI player.

[wildweasel]

What about older ZDooms? The least I need to know is if this is an issue of removing the MUSLIB code or something in the MIDI player.

Since I still had ZDoom 2.8.1 on hand to test with, I recorded a sample with that as well: http://picosong.com/7eKA/ - OPL emulator, MAME OPL2, 2 chips, full stereo panning enabled. The string bass doesn't drop out.

[Graf Zahl]

Did you test with 3.0.1 or with the latest master? I fixed some bug on May 8th, not that this is related to that one.

[wildweasel]

Did you test with 3.0.1 or with the latest master? I fixed some bug on May 8th, not that this is related to that one.

My copy of GZDoom identifies itself as "G3.0.1"; the title bar reads "GZDOOM g3.0.1 64-bit (2017-05-01 22:44:58 +0200)". I'll test really quick on a dev build.

[not-edit] With GZDoom g3.2pre-4-gc300103 64-bit (2017-06-01 00:26:25 +200), on OPL emulator set to MAME OPL2, 2 chips, full stereo panning, the bug still persists, and the string bass fades out. Recording a sample would be redundant.

[Graf Zahl]

Ok, so it seems this is related to the MUSLIB removal. Would be nice to have a song that only used one channel, but that'd require someone with some skills to edit the song.