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WAIL32.DLL — Miles Sound System (AIL) audio driver

WAIL32.DLL (135 KB) is the audio library the game executable's sound subsystem (#220) drives. It is not FA-authored code: it is the Miles Sound System (the Audio Interface Library, AIL) by Miles Design / RAD Game Tools — WAIL32 = "Windows AIL, 32-bit". Its 130 public exports are the documented Miles AIL_* API; the ~373 internal functions are Miles' own mixer, XMIDI player, and statically-linked C runtime.

Provenance: Ghidra static analysis of WAIL32.DLL (imported into the fa-re project, auto-analysed; public names from the PE export table). Third-party middleware, documented at the boundary per the license rule — the AIL_* API surface is named; Miles internals are waived, not reverse-engineered (#247 / #253). Confidence markers follow spec-authoring.md.

Boundary treatment

Miles Sound System is licensed third-party middleware — the same category as the Microsoft redistributables (DDraw / dsound / msapi) documented at the boundary rather than reversed. Its internal mixer/sequencer implementation is not FA's IP and its public API is already documented by Miles, so this page names the exported AIL_* API (the surface the game executable links against) and waives the internals. Every one of the 503 functions is accounted for: 130 named exports, 373 waived (Miles internals + statically-linked CRT), and the 577 referenced data globals are waived as Miles-internal state.

WAIL32.DLL: the game executable's sound subsystem calls the Miles AIL public API (digital samples + XMIDI sequences); AIL dispatches to third-party Miles internals over WINMM and DirectSound.

The AIL API surface

The API splits into three groups, all reached from the game executable's sound path:

  • Digital samples — PCM/.11K playback: AIL_allocate_sample_handle → AIL_init_sample → AIL_start_sample; AIL_set_sample_volume / AIL_set_sample_pan; AIL_end_sample.
  • XMIDI sequences — music: AIL_allocate_sequence_handle → AIL_init_sequence → AIL_start_sequence / AIL_stop_sequence; AIL_set_sequence_volume, AIL_register_sequence_callback; masters AIL_set_digital_master_volume / AIL_set_XMIDI_master_volume.
  • Driver + quick API — AIL_startup / AIL_shutdown, and the one-call AIL_quick_startup / AIL_quick_load / AIL_quick_play / AIL_quick_load_and_play.

Functions

Representative exports (VAs from the symbol DB; all 130 are named there):

VA Export Role
0x200019C0 AIL_startup initialise the AIL system
0x20001CF0 AIL_shutdown tear down the AIL system
0x20002D60 AIL_allocate_sample_handle reserve a digital-sample voice
0x20003060 AIL_init_sample bind a sample voice to a format
0x200033A0 AIL_start_sample begin playback
0x200035B0 AIL_end_sample stop a sample voice
0x20003710 AIL_set_sample_volume per-voice volume
0x200037C0 AIL_set_sample_pan per-voice pan
0x20004020 AIL_digital_master_volume read the digital master volume
0x20005360 AIL_allocate_sequence_handle reserve an XMIDI sequence
0x20005500 AIL_init_sequence load an XMIDI sequence
0x20005630 AIL_start_sequence begin music playback
0x200056C0 AIL_stop_sequence halt music
0x20005910 AIL_set_sequence_volume music volume
0x200067A0 AIL_register_sequence_callback per-sequence event callback
0x20005E90 AIL_set_XMIDI_master_volume XMIDI master volume
0x20008570 AIL_quick_startup one-call init
0x200086B0 AIL_quick_shutdown one-call teardown
0x20008730 AIL_quick_load one-call sample load
0x200088D0 AIL_quick_play one-call sample play
0x20008B90 AIL_quick_load_and_play one-call load + play

the game executable ↔ AIL boundary

The game executable's sound subsystem (#220) links WAIL32.DLL and calls into this API — confirmed call sites include AIL_startup / AIL_shutdown, AIL_set_preference, AIL_lock / AIL_unlock, AIL_start_timer / AIL_stop_timer, AIL_end_sample, AIL_sequence_status, and AIL_release_sequence_handle. The pause/resume path (PollMod, see sound.md) suspends and resumes the active XMIDI sequence through AIL_stop_sequence / AIL_resume_sequence. On the far side, AIL drives WINMM (midiOut* / waveOut*) and DirectSound.

Open Questions

1. Internal mixer / XMIDI implementation

The 373 waived internals are Miles' private mixer, XMIDI interpreter, and CRT — deliberately not reversed (third-party IP; the public API above is the documented boundary). No FA understanding depends on them.

Status: resolved — boundary-documented (third-party; internals out of scope by license).