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Google Meet & Virtual Audio Pipeline

The Google Meet integration enables the assistant to participate in scheduled virtual conferences, transcribe multi-party discussions, and provide real-time meeting synthesis.

1. Headless Virtual Display & Audio Topology

graph TD
    subgraph ContainerEnvironment [Podman Quadlet Container: Unprivileged User]
        Xvfb[Xvfb :99 Headless Virtual Display]
        PipeWire[PipeWire Audio Daemon]
        WirePlumber[WirePlumber Session Manager]

        Sink[Virtual Audio Sink: virtual-sink]
        Source[Virtual Audio Source: virtual-mic]

        Chromium[Headless Browser: Meet Client]
        Core[Assistant Audio Engine]

        Chromium -->|Speaker Output| Sink
        Source -->|Microphone Input| Chromium

        Sink -->|PCM Frame Capture| Core
        Core -->|TTS Audio Injection| Source
    end

    subgraph ExternalCloud [Google Cloud Services]
        STT[Google Speech-to-Text API]
        TTS[Google Text-to-Speech API]
    end

    Core -->|Encrypted Streaming gRPC| STT
    TTS -->|Synthesized Audio Stream| Core
  1. Virtual Display & Audio Loopback: The container operates a headless X11 server (Xvfb) and a local PipeWire audio daemon. Virtual audio nodes (virtual-sink and virtual-mic) decouple the browser from physical hardware.
  2. Headless Browser Execution: A sandboxed Chromium browser connects to the designated Google Meet meeting URL.
  3. Real-Time Speech Processing: PipeWire captures incoming audio frames from the virtual sink and streams them over encrypted gRPC channels to the Google Speech-to-Text API for transcription.

2. Privacy & Anti-Eavesdropping Invariants

  • Explicit Invitation Trigger: The assistant never joins meetings autonomously without an explicit calendar invitation or direct invitation link dispatched by an authorized meeting participant.
  • Dormant Default State: When no scheduled conference is active, audio daemons and browser processes are completely stopped. The system does not maintain passive listening streams.
  • Zero Audio Storage: Raw audio frames are processed in-flight in volatile memory and discarded immediately following transcription. No raw audio files (.wav, .mp3) are written to disk.
  • Participant Transparency: The assistant enters the conference with a clearly identifiable display name and visual avatar, notifying participants of automated note-taking.

3. Threat Model & Mitigations

Threat VectorAttack PathSecurity Mitigation
Browser Sandbox EscapeMalicious WebRTC or JavaScript payload delivered through Google Meet.Chromium sandbox enabled with strict seccomp filters. Container operates under rootless user (UID 1000) with restricted namespace capabilities.
Ambient Audio LeakageLeaking private conversation before or after meeting.Lifecycle hooks terminate browser and PipeWire processes immediately upon meeting conclusion or when participant count drops to 1.
Unauthorized Meeting InfiltrationBot joining private or restricted meetings.Meetings are validated against allowed corporate domains. Uninvited connection attempts are rejected.
Cloud Credential AbuseContainer IAM identity misused for data access.Ambient service account holds only roles/speech.client. It cannot read mailboxes, chat history, or Cloud Storage buckets.