SFX/Music Volume controls both affect program mixer volume

[trigger-segfault]

Describe the issue
Changing the Music or SFX volume from the options menu only changes the Windows Mixer volume. This affects the volume of the entire program, and also defeats the point of separating Music and SFX channels. It's assumed that this issue started on newer OSes (I read the change happened some time around Vista).

Expected behaviour
Changing the Music or SFX volume should independently change only that channel of audio. Also it's terrible practice to change volume level through the windows mixer (unless it's a master volume control), so ideally that shouldn't be happening either.

Steps to reproduce

1. Run OpenLRR or LegoRR.
2. Right click on the Windows volume tray icon and select Open Volume mixer.
3. Enter a level in-game.
4. Open the options menu.
5. Change the SFX or Music volume sliders and observe them changing the mixer volume for OpenLRR/LegoRR. Also note that SFX will change music volume, and Music will raise/lower the SFX clicking sound from changing the slider.

Additional information

• Time played this session: Any
• Level: Any
• Game speed: 0%-300%
• Graphics fix: dgVoodoo 2.55.4
• Using mods: None

Steps to fix

• Isolate SFX volume
• Isolate Music volume

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Possible solutions
This will essentially require ripping out and replacing most of the DirectSound and MCI audio functionality. MCI needs to be replaced, since it just uses waveOut, and that uses the program's master volume. Meanwhile DirectSound's primary sound buffer also affects the entire program's volume.

It may be possible to load all sounds under a secondary buffer duplicated from the primary one, this way setting the volume of the secondary (shouldn't?) affect the master volume. Music would also need to be moved to DirectSound or some other API that allows volume control, this means we'd need to eliminate original disc music support from OpenLRR!!! And also decide on a music format to support, and include the associated library. Worst case is we just switch to wav format.