| # SPEC-DRIVERS — backend interface specs |
|
|
| Every layer is a driver with a common interface, chosen per run. A driver |
| never prints; it raises typed errors and the CLI maps them to exit codes. |
|
|
| ## Error contract |
|
|
| | Exception | Exit | Meaning | |
| |---|---|---| |
| | `ValidationError` | 2 | bad input (URL, missing image, unknown driver) | |
| | `DriverError` | 3 | transport failure (HTTP, WebSocket, track error) | |
| | `SessionError` | 4 | session refused/failed/closed by remote | |
| | `CapabilityShortfall` | 6 | driver deps/config missing on this host; carries `capability` + `remediation` | |
|
|
| ## PresenceDriver |
|
|
| ```python |
| class PresenceDriver: |
| name: str # registry key: "browser" | "livekit" | "sip" |
| audio: bool # owns a mic track? |
| video: bool # owns a camera track? |
| |
| join(meet_url, platform, bot_name, image, voice, |
| system_prompt, meeting_password) -> session_id |
| status(session_id) -> "joining" | "ready" | "error" | "closed" |
| video_connected(session_id) -> bool |
| bot_connected(session_id) -> bool |
| leave(session_id) -> None |
| ``` |
|
|
| Contract rules: |
|
|
| 1. `join` returns a driver-global session id stable across CLI invocations |
| (leave is a separate process). |
| 2. Sessions must survive the joining process — state lives in a driver |
| registry on disk (`.freestream/sessions/<id>/driver.json`), not in memory. |
| 3. `join` must emit event-log entries (`driver.join_attempted`, |
| `session.created`, `session.status`, …) when a log is attached. |
| 4. Missing host capabilities are `CapabilityShortfall`, never crashes. |
| 5. Sessions must survive process teardown — state lives in a driver |
| registry on disk (`.freestream/sessions/<id>/driver.json`), not in memory. |
|
|
| ## livekit driver (MVP target) |
|
|
| - Joins a LiveKit room via `livekit-rtc` with a local track: mic-in fed by |
| the persona TTS output, camera-in fed by the avatar frame sink. |
| - ASR subscribes to remote audio tracks; faster-whisper consumes them. |
| - Lowest jitter of the free drivers; requires the meeting to run on |
| LiveKit/Jitsi (self-hosted or open instance). |
| - Config: `LIVEKIT_URL`, `LIVEKIT_TOKEN` (room-local token minted by |
| `freestream` for bot-name). |
|
|
| ## browser driver (post-MVP) |
|
|
| - Playwright/Chromium joins as a guest; virtual camera (v4l2loopback on |
| Linux, BlackHole + AVFoundation on macOS) supplies avatar frames; virtual |
| mic supplies TTS audio. |
| - Needs per-platform **join packs**: URL validation, guest-button selectors, |
| permission-grant selectors, pre-admit waiting-room handling. Selector |
| drift is the maintenance hotspot; packs are versioned and pinned per |
| platform build (see docs/PLATFORMS.md). |
| - Commercial platforms (Meet/Zoom) are ToS gray zones — shipped last. |
|
|
| ## sip driver (audio-only) |
|
|
| - Dials a conferencing bridge via SIP; near-zero cost, no video. |
| - Fidelity rung caps at AUDIO_REACTIVE_WAVE (no camera track). |
| - Config: `FREESTREAM_SIP_URI`, trunk credentials. |
|
|
| ## Persona drivers |
|
|
| - `VoiceBackend`: `piper` (default, CPU real-time) → `xtts-local` (cloning). |
| `clone()` returns the Pika-compatible dict and writes `life/voice_id.txt` |
| + `life/voice_config.json`. Clones are local files, never uploaded. |
| - `AvatarBackend`: selected by `select_rung()` from the fidelity ladder |
| (FULL_PORTRAIT 4 → STATIC_CARD 1). Rung degrades downward at runtime if |
| measured FPS < target for 5s; every downgrade is an event-log entry. |
|
|
| ## Cognition |
|
|
| - MCP server (`freestream/mcp_server.py`): stdio JSON-RPC by default, |
| HTTP when `FREESTREAM_MCP_HTTP=host:port`. Tools: `session.observe`, |
| `session.speak`, `session.listen`, `session.leave`. The agent is the |
| participant; FREESTREAM owns presence and persona only. |
