📰 Your Site Name

Subgen: Self-Hosting an Automated Subtitle Generator

2026-02-16
#homelab#proxmox#docker#self-hosting

Subgen: Self-Hosting an Automated Subtitle Generator

Adding subtitles to your personal media library is a practical way to improve accessibility and searchability. For homelab enthusiasts running Jellyfin, Plex, or Emby, integrating subtitle generation without relying on third-party services can keep your setup private and under control. Subgen is a self-hosted tool that automates subtitle creation using OpenAI’s Whisper model, and it integrates with popular media servers and management tools like Tautulli and Bazarr.

Why Subtitle Automation Matters in a Homelab

Manual subtitle searching and syncing can be tedious, especially if your media library grows beyond a few dozen files. While many media servers support fetching subtitles from online databases, these sources may not always have accurate or timely subtitles for less common content or personal recordings. Running an automated subtitle generator locally means you control the process, avoid privacy concerns, and can generate subtitles for any media, including home videos.

For sysadmins and homelabbers, this aligns well with the goal of minimizing external dependencies. It also offers an opportunity to experiment with AI models like Whisper in a practical, low-risk environment.

How Subgen Works and How to Set It Up

Subgen uses the Whisper speech-to-text engine to transcribe audio tracks from your media files and generate subtitle files (SRT format). It supports integration with:

  • Jellyfin
  • Plex
  • Emby
  • Tautulli (for monitoring playback and triggering subtitle generation)
  • Bazarr (for managing subtitle downloads and sync)

Basic Architecture

  1. Media Server: Your existing Jellyfin, Plex, or Emby instance serves media.
  2. Subgen Service: Runs on your homelab server or a container, monitoring media folders or receiving API calls.
  3. Integration Layer: Subgen hooks into media server events or Tautulli notifications to trigger subtitle generation.
  4. Storage: Subtitles are saved alongside media files or in a designated folder for your media server to pick up.

Setup Steps

  • Deploy Subgen as a Docker container or directly on a Linux host.
  • Configure API keys or tokens for your media server and Tautulli if used.
  • Point Subgen to your media directories or configure it to listen for playback events.
  • Adjust Whisper model parameters if needed (e.g., language, model size).
  • Test with a sample media file to verify subtitle generation and syncing.

I remember the first time I set this up, the biggest hurdle was tuning the audio extraction parameters to avoid poor transcription quality on older recordings.

Trade-offs and Limitations

  • Resource Usage: Whisper models can be CPU and memory intensive. On modest homelab hardware, expect longer processing times or consider running smaller Whisper models to balance speed and accuracy.
  • Accuracy: While Whisper is robust, transcription accuracy depends on audio quality, language, and background noise. Manual corrections may still be necessary.
  • Integration Complexity: Setting up event-driven triggers with Tautulli or Bazarr requires some scripting or API familiarity.
  • Storage Overhead: Subtitles add extra files to your media folders, which may require periodic cleanup or organization.

Subgen is not a replacement for professionally created subtitles but offers a good balance for personal media libraries where convenience and privacy are priorities.

Actionable Next Steps

  • Identify which media server(s) you want to integrate with Subgen.
  • Prepare a test environment with sample media files and verify audio quality.
  • Deploy Subgen on a container or VM with access to your media storage.
  • Configure integration with Tautulli or Bazarr if you want automated triggers.
  • Monitor CPU and memory usage during transcription to adjust Whisper model settings.
  • Set up a routine to review and correct subtitles as needed.

Subgen is a practical example of how AI tools can be integrated into homelabs to automate routine tasks. I ran a flat LAN for years before finally segmenting storage and backups, and tools like this make me rethink how much automation I want to add next.

Sources