[freezy]

Table audio needs a shared processing stage for EQ, dynamics and room effects. This adds an opt-in native stereo PCM renderer with seven semantic buses, followed by live stereo DSP. Existing configurations keep standard playback. Supported voices share one carrier without duplicate playback; custom mixer routes and unsupported or over-budget clips retain their existing route with diagnostics.

Each bus and the stereo output have eight EQ bands and a stereo-linked soft-knee compressor. A shared Signalsmith reverb return accepts independent post-processing bus sends; ROM defaults to no reverb. A final stereo-linked sample-peak limiter uses a fixed 1 ms lookahead with matching dry delay. Parameters are normalized off the audio thread, graph updates and retirement use bounded queues, and rendering performs no allocation, locks or file access. Pause, mute, unload and device reset clear or restore state safely, including saved master gain before first playback.

The renderer owns clip cursors, loops, pitch, panning and gain ramps. Optional bank bus IDs survive .vpe packaging, including unknown IDs and legacy defaults. ROM takeover requires an exclusive playback lease and explicit integration gain metadata; raw PCM remains available to other subscribers. Player-owned processing preferences are excluded from tables. Signalsmith sources are pinned, two local fixes are documented, and runtime resources include MIT/Boost notices.

An additive optional recorded-clip preview API auditions three bounded flipper strokes through the selected bus and DSP while game voices remain paused. Clip and bus are published atomically; stop and sample-rate changes cancel it safely. Legacy ABI and preview calls remain compatible. The companion Player bundles the recording and exposes clear effect sections, per-table scope, retained private drafts and an explicit Apply footer.

Validation:

• Core and Player compilation passed using Unity reference assemblies, including the exact proposed commits with unrelated working edits excluded.
• Windows x64/x86 and Linux native routing, PCM and DSP suites passed, including stereo linking, limiter ceilings, reverb reset, handoff, zero callback allocations and recorded-preview pause/resampling/stereo/stop/duration/rate-change cases.
• Eight Unity processing-settings tests passed during the DSP implementation; 37 final standalone production-package UI/runtime checks passed, including the real atomic Player store, Apply rollback/retry, retained scope drafts, cabinet scrolling and bidirectional native EQ curves.
• Standalone stereo/live-effects/pause/mute/reset/teardown checks passed. T2 retains 41 banks and 214 readable clips; table assignments and packaged audio banks are unchanged.
• Fable 5.1 and Astra 6 reviewed before commit. Their navigation, painter-lifetime and curve findings were corrected and verified; no actionable findings remain.

Companion Player PR #11 provides controls, presets and table overrides; PinMAME PR #48 supplies integration gain metadata. Native binaries are generated by CI rather than committed. Physical SSF, adaptive ROM drift and non-Windows playback qualification remain future work. Processing remains opt-in stereo.

Low-latency output and plugin audio

Three further commits measure and cut the mixer's output latency, then route plugin audio through it.

• audio: play the central PCM mixer through a native WASAPI stream. Unity's output path added its four-block ring plus FMOD's device buffer, about 40 to 50 ms on top of what Windows needs. The graph now renders on its own event-driven WASAPI shared stream (MMCSS thread, one engine period plus 3 ms queued, follows default-device changes, widens its margin per underrun once settled), with Unity's carrier as fallback.
• audio: add exclusive WASAPI and ASIO output modes for the central mixer. Exclusive WASAPI negotiates the device's own format. ASIO lives in a separate GPLv3 library (VisualPinball.Native~/Asio) that links the Steinberg ASIO SDK; one owner thread drives the driver, reset requests and rate changes reinitialize it, and the driver's control panel can be opened with or without a table.
• audio: route plugin audio through the central mixer. Seven more live inputs (PcmAudioStream), SoundPlayback.Play(source, bus) for plugin clips (listener-relative pan, Unity-style rolloff, mono copy for 3D voices), and GamelogicAudioPump for emulators that pulled their queue in a Unity filter. Buffered inputs have a jitter buffer sized from both sides' blocks and are steered against clock drift. The ROM stream previously drifted late without bound (141 ms queued on ASIO); it now holds about 22 ms.

Measured from a flipper key to the audio interface's own output (its loopback input, recorded through ASIO): Unity output 174 ms, native shared WASAPI 132 ms, exclusive 133 ms, ASIO at 64 frames 14 ms. ASIO4ALL on the same interface stayed at 115 to 122 ms, since it goes through the device's Windows driver. Plugin audio through ASIO: a stream push reaches the device in about 14 ms, a plugin clip in 8 ms.

Native routing and PCM suites (3,051 checks, including live WASAPI output, stream reuse, drift and burst cases) pass on Windows x64. Code review rounds found and fixed: a carrier/device handover race, ASIO reinitialization on reset and rate change, pause on fallback, stream slot reuse and producer races, VLC timing, and video channel layouts. VpeAsio.dll is not built by CI yet; without it the Player's ASIO choice falls back to normal output.

Companion PRs: Player #11 (output settings), Kiki, P-ROC and PinUP (plugin audio routing), and the B2S backglass.

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The latest changes appear safe to merge and address all three numbered previous findings.

Summary

Adds opt-in stereo PCM playback with semantic buses, shared effects, native Windows output options, and plugin audio inputs. Standard playback remains available.

• Supported table sounds can play through a shared stereo mixer and device output.
• Each sound bus and the stereo mix can use live effects.
• ROM and plugin audio can join the shared mixer as live PCM.
• Audio developers can build an isolated probe for routing PCM channels.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  Clips[Supported clips] --> Buses[Seven sound buses]
  Inputs[ROM and plugin PCM] --> Buses
  Buses --> Effects[Bus and output effects]
  Effects --> Output{Output route}
  Output --> ASIO[ASIO]
  Output --> WASAPI[WASAPI]
  Output --> Unity[Unity carrier]
  Fallback[Unsupported clips and pause-menu sounds] --> Reference[Unity playback]

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_{Reviews (7) · Last reviewed commit: "audio: keep the mixer's clock running th..." · Reviewed by Greptile}