Floor Bot Analysis

Skill: Floor Bot Analysis

This skill explains how to debug and analyze the Floor Bot feature in VoxBento, which bridges the Jitsi WebRTC audio floor track to the RTSP/MediaMTX infrastructure for transcription.

Overview of Floor Bot

The floor-bot is a headless Playwright/Chromium container that joins the main Jitsi conference room (monitoring the floor channel). It captures the audio and sends it over a PulseAudio socket directly to FFmpeg. FFmpeg then pushes this audio via RTSP to MediaMTX, where the transcription worker pulls it and generates captions.

Key Components

• floor-bot container: Runs bot.py via an HTTP server. It listens on port 8080 for /start and /stop commands.
• PulseAudio Socket: /tmp/pulse-{event_slug}.sock acts as the bridge. Chromium outputs to this socket, and FFmpeg reads from it.
• MediaMTX RTSP Path: Audio is pushed to rtsp://mediamtx:8554/{event_slug}/floor.
• FastAPI Backend: Admin routes /api/rooms/{room_id}/floor-transcription/start trigger the bot to join the Jitsi room and immediately spawn the transcription worker pointing to the floor channel.

Local Development vs. Production

When deploying this architecture, understanding the network topology is critical.

1. Jitsi Internal URL (JITSI_INTERNAL_BASE)

• Local: In Docker Compose, the Jitsi service is named jitsi-web. To bypass WebRTC HTTP origin blocking for getUserMedia, the backend automatically replaces localhost or jitsi.voxbento.com with the Docker-internal HTTPS URL: https://jitsi-web. The bot explicitly uses --ignore-certificate-errors and --unsafely-treat-insecure-origin-as-secure=https://jitsi-web.
• Production: If Jitsi is deployed outside of the docker-compose network (e.g., a standalone public Jitsi cluster), the internal https://jitsi-web hostname will fail. You must set JITSI_INTERNAL_BASE to the public Jitsi URL (e.g., https://jitsi.eventyay.com) in your .env.

2. MediaMTX RTSP Base (MEDIAMTX_RTSP_BASE)

• Local: Defaults to rtsp://mediamtx:8554 (the container name inside Docker Compose).
• Production: If MediaMTX is hosted elsewhere, override this via the MEDIAMTX_RTSP_BASE environment variable. Both the floor-bot FFmpeg ingest and the backend transcription worker use this URL.

3. Floor Bot API (FLOOR_BOT_BASE)

• Local: Defaults to http://floor-bot:8080.
• Production: If deployed on a different orchestration layer (like Kubernetes), override FLOOR_BOT_BASE to point to the correct pod/service DNS.

Common Debugging Steps

1. Bot is Silent / No Audio

Check if Playwright is muting the browser. Ensure --ignore_default_args=["--mute-audio"] is being passed. Also verify if the Jitsi UI is trying to acquire mic permissions and failing: Ensure --use-fake-device-for-media-stream is used.

2. Name is "Fellow Jitster"

Jitsi expects URL parameters (like userInfo.displayName) to be valid JSON strings. Ensure the display name is properly quote-wrapped and URL encoded: urllib.parse.quote('"VoxBento FloorBot"') -> %22VoxBento%20FloorBot%22.

3. Connection Refused to Pulse Socket

Ensure PULSE_SERVER="unix:/tmp/pulse-{event_slug}.sock" is properly passed to the Playwright chromium browser using the env= dictionary.

4. FFmpeg Demuxing/DTS Loops

If FFmpeg reports loop/sync errors (Non-monotonous DTS), check the sample rate constraints in Jitsi vs Chromium vs FFmpeg.

Debugging Commands

Tail the Floor Bot Logs: docker compose logs -f floor-bot

Check PulseAudio Connections inside Floor Bot: docker compose exec floor-bot sh -c 'PULSE_SERVER="unix:/tmp/pulse-{event_slug}.sock" pactl list sink-inputs' (If the browser is outputting audio correctly, you will see 'Chromium' listed as a client).

Check FFmpeg/MediaMTX Streaming: docker compose logs -f mediamtx (Look for: [path {event_slug}/floor] stream is online)