Cross platform audio, single audio thread, full audio emulation accuracy, full implementation of the entire SB PCM, SB DSP, SB Hardware mixer, SB reset delay, OPL port read/write delays, SB variants, OPL3, OPL2, dual OPL2, Adlib Gold Music and surround effects, and rewired PC Speaker. Full software mixer UI on top.

[maximilien-noal]

Description of Changes

Fixes all PCM and music rendering issues by using the latest dosbox staging architecture for the software mixer, which runs on its own thread, and update every related class along with it (PC Speaker, Sound Blaster, OPL, ...)

It uses less threads. The audio logic is inverted: the software mixer pulls audio data from devices.

For comparison here is the old audio thread logic from the master branch:

It uses more threads, and is less efficient. It is also crash prone. EIther the emulated program crashes, or the emulator itself crashes.

Rationale behind Changes

Vastly improved audio quality, performance, architecture, hardware emulation, and hardware compatibility.

Fixes crash issues related to sound threads.

Re-architectures the entire audio logic, for better performance and emulation accuracy.

Makes Dune, Lost Eden, Krondor, and so many other games sound as they should, for the PC Speaker, SB PCM, OPL3, OPL2, Dual OPL2, and Adlib Gold OPL.

Fixes #1513 #1514 #1464

Also fixes Where in Space is Carmen Sandiego from locking up, and so many game compatibility issues.

Status

The code is now 100% ported and 100% correct.

Audio is performant and fully cross platform. Works on Windows, Linux, MacOS, x86_64, and ARM64.
No native dependencies anymore. Pure C#. The audio backend code is ported from SDL 2 source code into C#.

See: https://github.com/OpenRakis/Spice86.Audio/tree/main/src/Spice86.Audio for details

All games I could test work fine.
The code is ready for review

Suggested Testing Steps

Test General MIDI, MT-32, PC Speaker, Sound Blaster PCM, Sound Blaster OPL, Sound Blaster variants (Sb16, Sb1, Sb2, SbPro1, SbPro2), sbmixer on/off and, Adlib Gold music (with surround module!) on whatever platform you want (Linux, Mac, Windows, x86_64, ARM64)

Except for MT-32 on MacOS ARM64 (which still lacks a native dependency), all devices on all platforms should be accurate, sound at it should sound, be fast, and overall just work.

(in Release build, that is! -- A 'problem' inherited from master branch is that sometimes Debug build can slow down on large video updates - this won't affect the Nuget package since it's compiled in Release mode with all compiler optimizations)

[github-advanced-security]

CodeQL found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.