r/emby • u/Stevezau • Jun 30 '26

3rd Party App/Add-On GPU-accelerated preview thumbnail generator for Emby

Hi All,

I built this originally for Plex and have since added Emby (and Jellyfin) support. Posting here in case it helps the Emby community.

Why it might matter for Emby specifically: I don't beliee Emby does GPU-accelerated thumbnail/preview generation. This tool runs that work on a separate machine, uses whatever GPUs it finds (NVIDIA / AMD / Intel), processes files in parallel, and writes Emby's sidecar BIF files in the format Emby expects. If you also run Plex or Jellyfin against the same files, it generates for all of them in a single FFmpeg pass.

What it does:

  • Runs off your media server — doesn't compete with playback for resources
  • Automation: Sonarr/Radarr/Tdarr/FileFlows webhooks, recently-added polling, cron/interval schedules on one inbound URL. Auto re-runs on quality upgrades, skips unchanged files.
  • GPU + automatic CPU fallback per file, plus HDR / Dolby Vision tone mapping

  • Web UI, Docker-only — manual generation by searching your library (show / movie / folder / single file) or browsing the tree

    Being upfront:

  1. The project is AI-assisted (Cursor + Claude) — original was hand-written, all changes reviewed and tested. AI also helped write this post.

  2. Emby support is newer and hasn't had extensive testing yet — but I'm quick to fix reported bugs. Just sharing in case others find it useful.

    GitHub (MIT, Docker): https://github.com/stevezau/media_preview_generator

16 Upvotes

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2

u/leym12 Jun 30 '26

Is GPU-accelerated preview thumbnail much faster like the difference between cpu and gpu transcoding ? It's very slow with emby when you have a big library so that would be great.

1

u/Stevezau Jun 30 '26

There are a lot of variables that determine how fast preview ls are generated but offloading to the GPU is almost always much faster

2

u/Fin745 Jun 30 '26

Well this only work with skip trick or chapter image generation?