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# Voice, Video & Calls System
Source files:
- Server: `routes/livekit.ts`, `ws/handler.ts`, `ws/events.ts`
- Client: `hooks/useLiveKit.ts`, `stores/voiceStore.ts`, `utils/voice.ts`, `utils/voiceActions.ts`, `utils/screenShare.ts`
- Shared: `packages/shared/src/constants.ts` (bitrate matrix, resolutions)
- Audio: `audio/AudioManager.ts`, `audio/SpeakingDetector.ts`
---
## Voice Channel Join Flow
1. Client sends `voice_join { channelId }` via WS
2. Server checks CONNECT permission, enforces one-room-per-user
3. Server loads voice restrictions from DB (space mute/deafen)
4. Server broadcasts `voice_state_update { action: 'join' }` to space
5. Client calls `POST /api/livekit/token { channelId }` → gets JWT + LiveKit URL
6. Client connects to LiveKit room with token
**Token grants (space channels):**
- SPEAK → can publish MICROPHONE + CAMERA
- STREAM → can publish SCREEN_SHARE + SCREEN_SHARE_AUDIO
- Missing permission → grant excludes those sources
**Token grants (DM calls):** Always full (canSpeak=true, canStream=true)
**Identity format:** `{userId}:{username}`, TTL: 1 hour, Room: `{channelId}` or `dm-{dmChannelId}`
**Multi-tab:** Each user has one `voiceWs` binding. New tab → old socket gets `voice_disconnected { reason: 'displaced' }`
---
## DM Call State Machine
States: `ringing``active` → destroyed
| Event | Action | State |
|-------|--------|-------|
| `dm_call_start` | Room created, caller bound, 60s timeout starts | ringing |
| `dm_call_incoming` | Broadcast to DM members (excludes caller) | ringing |
| `dm_call_accept` | First accept: ringing→active. Late joins welcome (group DM) | active |
| `dm_call_reject` | Room destroyed, caller unbound | — |
| `dm_call_end` | All participants unbound, room destroyed | — |
| Timeout (60s) | Auto-cleanup if still ringing, broadcast `dm_call_ended` | — |
**Edge cases:**
- Starting new call cancels any other ringing calls by same caller
- Socket close during ringing → auto-cleanup
- Participants drop to 0 in active state → room destroyed
---
## Federated DM Calls
DM calls work across federated instances. The caller's instance hosts the LiveKit room; remote clients connect to it directly. Call signaling is relayed to ALL active federation peers via synchronous HTTP POST (not the outbox worker). This ensures calls ring on every instance where a participant is connected, even if the DM is local-only on the caller's instance.
### Universal Relay
All `dm_call_*` signaling events (`start`, `accept`, `reject`, `end`) are relayed to every active federation peer in parallel via `Promise.all`. Each `sendCallRelay` call has a 10-second timeout. This is a synchronous HTTP POST to the peer's federation endpoint — it bypasses the outbox worker entirely because call signaling is latency-sensitive and must not be queued.
### Dual-Path Processing
When a peer instance receives a call relay, it uses one of two delivery paths:
| Path | Condition | Delivery |
|------|-----------|----------|
| **A** | DM exists on the receiving instance | Look up `dm_members` for the local `dmChannelId` and deliver to connected members |
| **B** | DM does not exist on the receiving instance | Match participants by `homeUserId + homeInstance` identity against connected WebSocket users |
Path B enables calls to ring for federated users even when no local DM channel has been created yet (e.g., first contact via a federated call).
### FederatedCallEntry
The in-memory call state (`FederatedCallEntry`) is keyed by `federatedId` (not `dmChannelId`):
- `dmChannelId` is **nullable** — null for Path B scenarios where no local DM channel exists
- `ringedUserIds` tracks all users who were notified of the incoming call, used for end-call cleanup
- `callerId`, `callerHomeUserId`, `callerHomeInstance` identify the caller across instances
### Late-Bind dmChannelId
When `findOrCreateDmChannel` creates a local DM channel during an active federated call (e.g., the first message arrives while a call is ringing), it binds the `dmChannelId` on the existing `FederatedCallEntry`. This transitions the call from Path B to Path A delivery without interrupting the call.
### Token Generation & Room Identity
**Token generation:** `generateFederatedCallToken(federatedId, homeUserId, displayName)` in `routes/livekit.ts` issues 5-minute tokens scoped to the `federatedId` room (not the local `dmChannelId`). Grants full DM permissions (mic, camera, screen share, subscribe, data channel).
**LiveKit URL:** The relay sends `config.livekit.url` (e.g., `wss://nova.ddns.net/livekit`). Must be `wss://`, not `https://` — the LiveKit SDK requires a WebSocket URL.
**Token endpoint:** `POST /api/livekit/token` uses `federatedId` as the room name when the DM channel has a `federatedId` set, ensuring both instances join the same LiveKit room.
**Identity format:**
- Federated calls: `${homeUserId}:${displayName}` — stable across all instances
- Local calls: `${userId}:${username}` — unchanged
**Client identity resolution:** For federated calls, the client splits the LiveKit participant identity on `:` and matches `homeUserId` against the DM member list (which stores `homeUserId` for all members). This resolves the correct display name and avatar regardless of which instance the participant is on.
### Client-Side Call Routing
**`callOrigin`:** Set to the WS origin that delivered the `dm_call_incoming` event (the home instance), NOT the call host URL. Accept/reject/end route through this WS. The home instance's server finds the `FederatedCallEntry` and relays to the host via S2S HTTP. This is reliable regardless of whether the client has a multi-instance WS to the host.
**`handleAccept`:** Sets `activeDmCall` and clears `incomingCall` directly in the click handler — does not wait for the server's `dm_call_accepted` response (races with `connectFn`'s async AudioContext resume).
**Passive ready handler:** On page refresh/restart, the ready payload includes active calls but the client does NOT auto-connect to LiveKit. Users must re-accept. This prevents identity slot wars when the same user has multiple sessions.
### SoundController Federation Awareness
The `SoundController` uses `isSelf(id)` which checks against BOTH `currentUser.id` (local snowflake) and `currentUser.homeUserId` (federated home ID). In federated calls, `updateParticipants` resolves identity to the local snowflake when `activeDmCall` is set, but reverts to raw `homeUserId` when it's cleared during disconnect. Both formats must be recognized as "self" to prevent phantom join/leave sounds.
**Disconnect teardown:** `roomRef` is set to `null` before calling `destroyRoom()`. This prevents `ParticipantDisconnected` events (fired during teardown) from triggering `updateParticipants`, which would cause `user_leave` sounds for departing participants alongside the disconnect sound.
---
## Voice Moderation
Three independent muting mechanisms:
### 1. User Self-Mute/Deafen
- Client toggles in `voiceStore`
- Broadcasts via `voice_status` WS event
- If also space-muted, remains effectively muted
### 2. Space Mute/Deafen (moderator, persisted)
- Requires MUTE_MEMBERS / DEAFEN_MEMBERS permission
- Stored in `voice_restrictions` table (survives reconnect)
- In-memory: `spaceMutedUsers` / `spaceDeafenedUsers` sets (`"spaceId:userId"` keys)
- On voice_join: restrictions loaded from DB into memory
- Broadcasts `voice_space_muted` / `voice_space_deafened` to all space members
### 3. Permission Mute (automatic, ephemeral)
- Triggered when user loses SPEAK permission (role update)
- `checkVoicePermissions(spaceId)` re-evaluates all users in space voice
- NOT persisted — derived from role permissions on demand
- Broadcasts `voice_permission_muted`
**Effective state:** `effectiveMuted = isMuted || spaceMuted || permissionMuted`
### Move & Disconnect
- `voice_move`: Requires MOVE_MEMBERS. Same space only. Preserves voice status.
- `voice_disconnect`: Requires DISCONNECT_MEMBERS. Full teardown.
---
## Screen Sharing
### Resolution & Framerate Options
```
Standard resolutions: 540, 720, 1080, 1440, 2160 (+ 'native')
Standard framerates: 30, 45, 60, 75, 90, 120
Width map: 540→960, 720→1280, 1080→1920, 1440→2560, 2160→3840
```
### VP9 Bitrate Matrix (kbps)
```
30 45 60 75 90 120
540: 1500 2000 2500 2800 3200 4000
720: 3000 3500 4000 4500 5000 6000
1080: 6000 7000 8000 9000 10000 12000
1440: 10000 12000 14000 16000 18000 22000
2160: 20000 24000 28000 32000 38000 45000
```
### Config Object
```typescript
ScreenShareConfig {
height: number | 'native', // Resolution or capture at display res
fps: number, // 30-120
mode: 'gaming' | 'text', // Affects bitrate & content hint
customBitrateKbps: number | null, // Admin override (if allowed)
shareAudio: boolean // System audio (disabled in Electron)
}
```
### Build Pipeline (`buildScreenShareOptions()`)
1. Resolve bitrate from matrix (custom > override > default > native estimate)
2. Clamp to instance limits (minBitrateKbps, maxBitrateKbps)
3. Compute min bitrate = 25% of max
4. Codec: VP9 (default) or H.264 (hardware overdrive)
5. VP8 simulcast backup at reduced framerate/bitrate
6. Content hint: `'detail'` (text) or `'motion'` (gaming)
### Native Mode
- Captures at display's full resolution
- Snaps to nearest known tier for bitrate lookup
- Scales proportionally: `baseKbps * (capturedPixels / knownPixels) * (fps / knownFps)`
### Hardware Overdrive
- Forces H.264 hardware encoder via SDP profile override
- Applied 2s after stream starts (after WebRTC negotiation), re-applied at 5s
- 4s: detects if using software fallback, warns user
### Instance-Level Limits (admin-configured)
- `allowedResolutions`, `allowedFramerates` (CSV in instance_settings)
- `maxResolution`, `maxFramerate`, `maxBitrateKbps`, `minBitrateKbps`
- `allowCustomBitrate` toggle
- `bitrateMatrixOverrides` (JSON sparse overrides)
---
## Audio Processing
| Feature | Default | User Control | Notes |
|---------|---------|-------------|-------|
| Echo Cancellation | on | yes | Stays on during screen share (Chrome AEC handles it) |
| Noise Suppression | overridden | — | Managed by RNNoise state |
| Auto Gain Control | on | yes | |
| RNNoise (ML) | on | yes | When enabled: browser NS forced off |
**Audio constraints applied to mic track:**
```typescript
{
echoCancellation: userSetting, // stays on during screen share
noiseSuppression: rnnoiseEnabled ? false : userSetting,
autoGainControl: userSetting,
}
```
**Screen share audio (when enabled):**
```typescript
{
restrictOwnAudio: true, // Chrome 141+: exclude own tab audio
echoCancellation: false,
noiseSuppression: false,
autoGainControl: false,
channelCount: 2 // Stereo
}
```
**Persistence:** `voiceStore` with Zustand localStorage. Keys: `echoCancellation`, `autoGainControl`, `rnnoiseEnabled`, `screenShareConfig`.
**Camera preset:** 1280x720, 2Mbps, 30fps, H.264