Crate tauri_plugin_system_audio 

Dual audio capture for Tauri 2 — microphone + system audio (WASAPI loopback) with WebRTC AEC3 echo cancellation.

Extracted from the production desktop app of SubcueAI.

  ┌─────────────┐    ┌─────────────┐    ┌───────────┐
  │ mic capture │───▶│  resampler  │───▶│   APM     │──▶ FrameEvent::Pcm (mic)
  └─────────────┘    │  to 16k f32 │    │ near-end  │
                     └─────────────┘    └───────────┘
  ┌─────────────┐    ┌─────────────┐    ┌───────────┐
  │ loopback*   │───▶│  resampler  │───▶│   APM     │──▶ FrameEvent::Pcm (loopback)
  └─────────────┘    │  to 16k f32 │    │ reverse   │
     *Windows only    └─────────────┘    └───────────┘

Mic and loopback are emitted as independent 16 kHz mono PCM streams (no additive mix), so the JS side can route each to its own consumer — e.g. two STT sockets tagged “local speaker” vs “remote party”. A mixer::Mixer utility is included if you want a single combined stream instead.

On Windows the loopback (system output) feed doubles as the far-end reference for WebRTC AEC3, so speaker bleed is cancelled from the mic before your app ever sees it. On macOS the plugin runs mic-only: Apple’s voice-processing I/O (VPIO) already does AEC at the OS level, and system-audio capture requires ScreenCaptureKit, which is out of scope here.

Modules

apm

mixer

resampler

Structs

AudioSession

CaptureOptions

What to capture and how to process it. All flags are orthogonal; defaults give you the full pipeline (mic + loopback + APM).

Enums

Error

FrameEvent

Events emitted to the JS side over the Tauri Channel.

PcmSource

Which physical source a PCM frame came from. Mic and loopback frames arrive interleaved on the same channel; consumers split on this tag — e.g. mic → “local speaker” STT, loopback → “remote party” STT.

Functions

init

Initializes the plugin. Registers start / stop / permission_status commands and, on Windows, resolves a bundled webrtc-apm.dll through Tauri’s resource resolver (works for tauri dev and tauri build alike).

Type Aliases

SharedSession