Emby Theme Maker

An Emby Server plugin that turns Emby's Intro Detection markers into per-series theme videos (backdrops/theme.mp4) and theme music (theme.mp3) — using the server's own built-in ffmpeg. No external tools, no API key.

It's the native-plugin evolution of an earlier command-line script: same idea, but it runs inside Emby and is driven from Scheduled Tasks.

What it does

For each TV series, the plugin:

1. Reads the intro markers (IntroStart / IntroEnd) straight from Emby's item database.
2. Picks a representative episode (median intro length — robust against cold opens / specials).
3. Cuts [IntroStart → IntroEnd] from that episode with Emby's bundled ffmpeg, re-encodes with fade in/out, and writes the result into the series folder.
4. Triggers a library scan so Emby registers the new theme media.

Output depends on the Mode setting:

Mode	Writes
Video	<SeriesFolder>/backdrops/theme.mp4 (h264/aac video backdrop)
Audio	<SeriesFolder>/theme.mp3 (theme music, series root)
Both	both of the above, in one pass

Requirements

• Emby Server 4.9.x (built/tested against 4.9.5.0, Windows & Linux).
• Intro Detection already run on your shows (that's where the markers come from).
• A bare-metal / VM install where Emby can write into your series folders. (In container/NAS setups where the series folders aren't writable by the server, it can't drop the theme files.)

No API key, no external ffmpeg — the plugin uses Emby's own item database and ffmpeg.

Install

1. Download EmbyThemeMaker.dll from the latest release (or build it — see below).
2. Drop it into your Emby plugins folder and restart the server:
   • Windows: …\Emby-Server\programdata\plugins\
   • Linux (deb/rpm): /var/lib/emby/plugins/
3. Open Dashboard → Theme Maker and configure it.

Usage

Everything runs from Dashboard → Scheduled Tasks:

• Theme Maker: Preview (read-only) — logs exactly what it would generate for each series (source episode, intro span, whether a theme already exists) without writing anything. Run this first.
• Theme Maker: Generate — actually encodes the theme files, per your settings.

Add a trigger to either (daily / interval / on startup) to run it on a schedule, or run on demand. All activity is logged to the Emby log with a [ThemeMaker] prefix.

Settings (Dashboard → Theme Maker)

Setting	Meaning
Output mode	video / audio / both
Overwrite existing themes	Regenerate even when a theme already exists (off = skip existing)
Only under this folder	Restrict to series whose folder is under this path (blank = all)
Limit	Process at most N series per run (0 = no limit)
Source episode	Median (robust) or First episode
Min / Max intro length	Ignore intros outside this range (seconds)
Pad start / end	Extend the cut before/after the markers (seconds)
Preferred audio language	e.g. jpn — picks that stream if present (blank = first)
Max video height / CRF / Preset / Peak bitrate	libx264 quality controls
Audio bitrate / Fade in / Fade out	audio + fade controls
Output filenames / backdrop subfolder	where and what to write
Parallel encodes	how many ffmpeg jobs at once
Scan library after generating	trigger one Emby scan at the end so new themes register

Safe by default: it never overwrites an existing theme unless Overwrite is on, and it never deletes a song out of a curated theme-music/ folder.

Building

Requires the .NET SDK. Targets netstandard2.0, references mediabrowser.server.core (Emby's NuGet); the Emby assemblies are provided by the host and are not bundled — the output is a single self-contained EmbyThemeMaker.dll.

dotnet publish EmbyThemeMaker/EmbyThemeMaker.csproj -c Release -o out
# -> out/EmbyThemeMaker.dll

To stamp a version, pass it in (CI does this from the git tag):

dotnet publish EmbyThemeMaker/EmbyThemeMaker.csproj -c Release -o out -p:Version=1.2.3

Releases

Pushing a tag like v1.2.3 triggers the GitHub Actions workflow, which builds the DLL, stamps it with the tag version, publishes a GitHub Release with EmbyThemeMaker.dll attached, and generates a build provenance attestation for the artifact (verifiable with gh attestation verify EmbyThemeMaker.dll --repo <owner>/<repo>).

License

GPL-3.0 — see LICENSE and COPYRIGHT.

You may use, modify, and redistribute it under the GPL-3.0. As the sole copyright holder, the author also reserves the right to offer it under separate (e.g. commercial) terms — see the dual-licensing note in COPYRIGHT.