voice-bridge: Discord voice <-> Lotus voice room (patched nether-voicebridge)

Production setup for the Discord voice bridge on LXC 151: config and appservice-registration templates (secrets rendered on the server), an idempotent install script (one Synapse restart on first install, creates the bot account so it can be invited), and a hardened systemd unit. voice-limit-guard: VOICE_LIMIT_EXEMPT_USERS lets the bridge's own bot listen in a call without taking a slot; relayed Discord speakers still count. Unit tests added (61 pass); verified live on the dev stack. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5
2026-10-29 12:51:56 -04:00
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commit 46d0e98424
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@@ -448,6 +448,40 @@ while the bridge or Synapse was down are bridged when it starts again.

 ---

+## Voice Bridge (nether-voicebridge, Lotus-patched)
+
+Bridges Discord voice into a Lotus voice room. People on Discord appear **inside the Matrix call**
+under their Discord names, with a speaking indicator. People in Lotus appear in the Discord channel
+as `[Matrix] <name>`, with mute mirrored to Discord.
+
+| | Text | Voice |
+|---|---|---|
+| Discord (Lotus Guild server) | #matrix-bridge | matrix-bridge |
+| Matrix (Lotus) | Discord Bridge (mautrix-discord) | Discord Voice Bridge (`!yS_ZIHL3sOKQJBt4NiIQyiHKt3cv6HrIDeq7OxDpSM0`) |
+
+- **Build:** upstream [nether-voicebridge](https://nether.codes/nether/nether-voicebridge) `cf52945`
+  plus 11 Lotus patches (reported upstream). Patches, bug log and issue drafts live in
+  `/root/code/voice-bridge-trial/`. **Don't run the unpatched release**. Without the patches the
+  bridge can't see anyone using current Element Call or Lotus Call (`livekit_alias`), and encrypted
+  voice breaks after a restart on Synapse.
+- **Accounts:** the bot is `@lotus-voice_bot`, shown in encrypted calls as "Discord Voice Bridge".
+  Discord speakers are `@lotus-voice_<discord id>`. The appservice registration is
+  `/etc/matrix-synapse/lotus-voice-registration.yaml`.
+- **Discord bots:** Lotus Voice 1–3, one per Matrix person speaking at once. Each has only Connect,
+  Speak, Use Voice Activity and Change Nickname, and none can see #matrix-bridge text.
+- **Files on LXC 151:**
+  - binary: `/opt/lotus-voice/lotus-voice-bridge`
+  - config: `/etc/lotus-voice/config.toml` (0600, holds the bot tokens)
+  - state: `/var/lib/lotus-voice`
+  - service: `lotus-voice-bridge`, logs via `journalctl -u lotus-voice-bridge`
+- **Voice limits:** `voice-limit-guard` ignores `@lotus-voice_bot` (`VOICE_LIMIT_EXEMPT_USERS`), so
+  the bot never takes a slot. Discord speakers count like anyone else. When a room is full the
+  bridge stops trying cleanly, and the Discord user just isn't heard.
+- **Install / upgrade:** on the Proxmox node hosting LXC 151, run
+  `bash voice-bridge/install.sh <binary> <secrets file with BOT1..BOT3>`. The first install
+  registers the appservice, restarts Synapse once and creates the bot account. Then invite
+  `@lotus-voice_bot:matrix.lotusguild.org` to the voice room. Upgrades just swap the binary.
+
 ## Bot profiles

 Every bot account has a proper name and an avatar in one style (white glyph on a coloured square). Image sources are in `avatars/` and `discord-bridge/bot-avatar.png`.