EAX 1.0 - Stereo music playback converts to mono

[Doze-D]

I've been fiddling with this pack with Martian Gothic Unification, as that game has EAX 1.0 support. Natively the game uses QSound QMDX.DLL to handle the conversation with hardware, but when I use any of these OpenAL/DSOAL packs to enable the EAX, game detects the EAX and it plays the mono audio files correctly. However, the music is stored in stereo in the game files, and should be played purely as stereo. But, the DSOAL/EAX seems to convert those stereo tracks to mono and pan them to the middle.

I did deeper research about QSound and accidentally stumbled upon their QMixer SDK header file, which might be useful over here with this project, since a lot of games did use QSound stuff in them back in the day.

https://www.mediafire.com/file/pggbojevs0cekt0/qmixer.h/file

[kcat]

Are you able to create DSOAL log files with the game? You can use this batch cmd file by dragging and dropping the executable onto it, and it should produce DSOAL and OpenAL Soft log files. There aren't many reasons DSOAL would try to downmix a stereo buffer, it would only happen when there are a confusing combination properties in an older DSound version that aren't clear what should happen. If this game is running into that, I can check what it's trying to do with the log and try to adjust the related logic.

[Doze-D]

Thanks, here's the logs, I included the one that the game always writes even if there's no errors, so you can see the pipeline how it proceeds with this

alsoft_error.txt
dsoal_error.txt
ERROR.LOG

[kcat]

Nothing in those logs stand out, unfortunately. It sets stereo for the primary buffer output, then creates a secondary buffer for stereo but never uses it, and everything else is made and played as mono. So whatever the reason it's playing as mono, it's QSound or the game itself explicitly saying to do it.

[Doze-D]

Okay, thanks for the info, I'll keep digging through those. So far it seems mysterious that where does the game convert the stereo music track into mono when EAX is enabled.

[mirh]

Wait, are you saying that only when you enable EAX there is this downgrade, or does it always just happen whenever you use dsoal?

[Doze-D]

Wait, are you saying that only when you enable EAX there is this downgrade, or does it always just happen whenever you use dsoal?

I haven't tried this in any other game so far, but I've done all the possible troubleshooting to rule out any hardware related things.

[mirh]

I didn't mention any hardware changes.
Assuming that out of the box the music plays stereo, I'm trying to understand if just using dsoal monofies the soundtrack or if it's EAX activation (either in-game or in alsoftrc) that causes it.

[Doze-D]

I didn't mention any hardware changes. Assuming that out of the box the music plays stereo, I'm trying to understand if just using dsoal monofies the soundtrack or if it's EAX activation (either in-game or in alsoftrc) that causes it.

Well my research so far seems to point out into the QMDX.DLL, hopefully it's a bug in the code. Either way, I gotta debug the game to get deep into the sound pipeline to find that specific place where it does that when EAX is detected and used.

[mirh]

... so you are saying that IF dsoal is used BUT eax is NOT enabled, this problem doesn't happen?

[Doze-D]

... so you are saying that IF dsoal is used BUT eax is NOT enabled, this problem doesn't happen?

No, the game launches with QMDX always, and the QMDX checks whether EAX is available or not. When dropping DSOAL into the game folder, EAX is detected always automatically, and the game uses that for the audio.

[mirh]

Ok, then what I'm asking is to disable EAX and see what happens.

[Doze-D]

Ok, then what I'm asking is to disable EAX and see what happens.

Then the game plays the music in stereo just like it should be. I did some digging to figure out the pipeline with this game. Exe communicates with QMDX, and QMDX decides what sound API to use. If EAX is not detected, it outputs stereo in WaveOut. But if EAX is detected, it reroutes the audio through DirectSound. The bug resides in the DirectSound pipeline in the QMDX.

[mirh]

If only we knew if this happened even 26 years ago on the original hardware...
https://web.archive.org/web/*/http://www.qsound.com/gamedev/qmdx-files/*
https://discmaster.textfiles.com/browse/32512/GMC%20GIOCHI%20PER%20IL%20MIO%20COMPUTER%20-%202003%20MARZO%20DVD.iso/shareware/Parsec/parsec_lan_build0197.exe/%7Bapp%7D/qmdx.dll
Here you should have qmdx 5.00 and 4.13 anyway, idk if they might make a difference (it seems strange a middleware would have *this* bug)

[Doze-D]

If only we knew if this happened even 26 years ago on the original hardware... https://web.archive.org/web/*/http://www.qsound.com/gamedev/qmdx-files/* https://discmaster.textfiles.com/browse/32512/GMC%20GIOCHI%20PER%20IL%20MIO%20COMPUTER%20-%202003%20MARZO%20DVD.iso/shareware/Parsec/parsec_lan_build0197.exe/%7Bapp%7D/qmdx.dll Here you should have qmdx 5.00 and 4.13 anyway, idk if they might make a difference (it seems strange a middleware would have this bug)

The game won't even boot with QMDX 5.0, someone managed to make it boot, but there was no sound with it. But thanks for showing these, I'll take a look.

[Doze-D]

Okay, so the issue is within the game's own executable. It completely lacks the required stereo format override when it sets up 2D channel for it. This issue is not related to DSOAL, but if it's okay, keep this discussion here for future references, could help with people with similar issues on games that use older EAX and/or QMDX.