jellyplex-sync 0.2.1

Convert your media library between Jellyfin and Plex formats by creating a hard-linked mirror

Bidirectional Movie Library Sync for Plex and Jellyfin

Can't decide between Jellyfin and Plex? This tool might help. It synchronizes your movie library between Jellyfin and Plex formats in both directions — without duplicating any files. Instead, it uses hardlinks to mirror your collection efficiently, saving storage while keeping both libraries in sync.

⚠️ 0.2.0 is a major rewrite. Subcommands, new materializer options, machine-readable --json output, default-sync-everything behavior, and a renamed model field (tags → labels in the Python API). If you depend on the old shape, try the new version with --dry-run first, and pin to a 0.1.x release if anything looks off. See the CHANGELOG for the full migration notes.

Overview

The script scans the source library, parses each movie folder for metadata (title, year, optional provider ID), and reproduces the same directory structure in the target location. Rather than copying video files, it creates hard links to avoid extra storage usage. Asset folders (e.g., extras, subtitles) are also mirrored. Loose top-level files (posters, NFOs, subtitles) are synced 1:1 by default since 0.2.0. With --delete, any files or folders in the target that are no longer present in the source will be removed.

Warning: This script will overwrite the entire target directory. Do not store or edit anything manually in the target library path. The source library is treated as the only source of truth, and any unmatched content in the target folder may be deleted without warning.

Note: This tool is only useful if your media library is well-maintained and each movie resides in its own folder.

⚠️ Movies only: This script is designed exclusively for movie libraries. It does not support TV shows or miniseries. However, this is usually not a limitation in practice: for shows, Jellyfin and Plex use very similar directory structures, so you can typically point both apps to the same library without issues.

⚠️ Hardlinks require a shared filesystem: Source and target paths must live on the same filesystem. Hardlinks cannot span filesystems or physical disks. If they don't, switch to --copy. On Unraid's classic array this is a real concern — see the Unraid section for details before running this tool there.

Installation

Python package (recommended)

The easiest way to install the CLI is via uv:

uv tool install jellyplex-sync

This places jellyplex-sync on your PATH in an isolated environment. pipx install jellyplex-sync works the same way if you prefer pipx.

Docker

A prebuilt container image is published to GitHub Container Registry:

ghcr.io/sniner/jellyplex-sync:latest

If you'd rather build it yourself:

docker build -t jellyplex-sync .

Usage

The CLI is split into two subcommands:

• sync — mirror a source library into the target layout (the historical operation; this is also the default if you omit the subcommand).
• diff — read-only comparison of source and target. No filesystem changes. Useful before deleting your source after a migration.

sync

jellyplex-sync sync [OPTIONS] /path/to/source/library /path/to/target/library

The first positional is the source library, the second is the target. By default the tool auto-detects whether the source is a Jellyfin or Plex layout and converts to the other format.

Options

• --create — create the target directory if it doesn't exist.
• --delete — remove stray folders/files in the target that have no counterpart in the source. Without this, strays are reported in the summary but kept on disk.
• --dry-run — show what would happen without touching the filesystem.
• -v, --verbose — log every processed movie.
• --debug — enable debug-level logging.
• --json — emit a machine-readable JSON document on stdout (see JSON output below). Stderr is automatically quieted to WARNING unless --verbose/--debug is set, so the document pipes cleanly into jq.
• --source-format {jellyfin,plex,auto} — declare the source library format. auto (default) inspects the source layout.
• --target-format {jellyfin,plex,auto} — declare the target library format. auto (default) picks the opposite of the source. Setting both flags to the same value puts the tool into lint/normalize mode (rewrite a library in its own format, e.g. to canonicalize Plex labels).

Materializer flags (mutually exclusive — pick at most one):

• --hardlink (default) — create a hardlink at the target pointing to the source inode. Requires source and target on the same filesystem.
• --copy — copy bytes. On re-runs, skips files whose target already has the same size and mtime as the source.
• --force-copy — always copy, no skip heuristic.

Use --copy when source and target are on different filesystems (NAS to local disk, cross-pool moves, etc.). The size+mtime check makes re-runs cheap.

Examples

Mirror a Jellyfin library into a new Plex structure:

jellyplex-sync sync --create ~/Media/Jellyfin ~/Media/Plex

Migration with cleanup (target becomes a clean mirror):

jellyplex-sync sync --delete --create ~/Media/Jellyfin ~/Media/Plex

Cross-filesystem copy with safe re-runs:

jellyplex-sync sync --copy --create /mnt/nas/Movies /mnt/local/Plex

Dry-run a verbose, full sync with deletion:

jellyplex-sync sync --dry-run --verbose --delete --create ~/Media/Jellyfin ~/Media/Plex

diff

jellyplex-sync diff [OPTIONS] /path/to/source/library /path/to/target/library

Compares the two libraries without touching anything. Reports movies that exist only on one side, file-level differences inside shared movies, translation losses (Plex labels with no Jellyfin equivalent, for example), and entries the scanner ignored.

Exit codes follow the Unix diff convention:

• 0 — in sync.
• 1 — differences found.
• 2 — setup error (missing directories, indecipherable format).

Example

Verify a target is a complete mirror before deleting the source:

jellyplex-sync diff ~/Media/Jellyfin ~/Media/Plex

JSON output

Both subcommands accept --json for machine-readable output. The document goes to stdout; logs continue to go to stderr. Under --json, INFO logs are suppressed unless you pass --verbose or --debug, so the output pipes cleanly into tools like jq without filtering.

The schema (still evolving — pin a version when consuming):

• operation: "sync" or "diff".
• exit_code: the process exit code, mirrored in the document for convenience.
• source / target: {path, format} for each endpoint.
• dry_run (sync only): whether the run was a preview.
• summary (sync only): counters for movies_total, movies_processed, files_updated, files_removed, items_ignored, strays_in_target.
• ignored: list of source-side entries the scanner skipped, each {path, name, reason}.
• strays_in_target (sync only): list of names found in target that aren't in source.
• translation_losses: distinct {kind, key, value, reason} tuples for labels/attributes the target format can't express. Deduplicated — one entry per distinct loss, not per affected file.
• events (sync only): flat array of per-file actions, each {action, target, source?, context?}. Actions are link, replace, skip, remove. For remove, context is library_stray / movie_stray / asset_stray. Action names are the same in --dry-run and real runs; the top-level dry_run flag tells you which mode you were in.
• diff-specific fields: movies_only_in_source, movies_only_in_target, differing_movies, in_sync.

jq examples

Show every file that would be replaced (with full paths):

jellyplex-sync sync --json --dry-run /src /dst \
    | jq '.events[] | select(.action == "replace") | {source, target}'

Verify nothing important gets deleted before running a migration with --delete:

jellyplex-sync sync --json --dry-run --delete /src /dst \
    | jq '.events[] | select(.action == "remove")'

Action distribution:

jellyplex-sync sync --json --dry-run /src /dst \
    | jq '[.events[].action] | group_by(.) | map({action: .[0], count: length})'

Default subcommand

For backward compatibility, omitting the subcommand is treated as an implicit sync (as long as the first argument is a positional, not a flag):

jellyplex-sync ~/Media/Jellyfin ~/Media/Plex

is equivalent to

jellyplex-sync sync ~/Media/Jellyfin ~/Media/Plex

If you start with a flag, you must spell out sync explicitly.

Docker

docker run --rm -v /your/media:/mnt ghcr.io/sniner/jellyplex-sync:latest sync /mnt/source /mnt/target

To try the tool, generate a small Plex-format library with jellyplex-gen and point the sync at it:

uvx jellyplex-gen plex --seed=demo --movies=20 --out=./demo-plex
mkdir ./demo-jellyfin
docker run --rm -v .:/mnt ghcr.io/sniner/jellyplex-sync:latest \
    sync /mnt/demo-plex /mnt/demo-jellyfin

Bind-mount note: With --hardlink (default), both source and target paths must be reachable inside the container through the same bind mount, otherwise hardlinks between them cannot be created. With --copy, this constraint goes away.

Unraid (User Scripts)

The repository includes a jellyplex-sync.sh helper you can add to the Unraid User Scripts plugin. It pulls the latest container image, removes outdated ones, and runs the sync. Adjust the source and target paths at the bottom of the script to match your library locations.

⚠️ Dry-run by default: The script ships with --dry-run enabled. It will only print what it would do — nothing changes on disk until you remove that flag.

⚠️ Array layout matters: Hardlinks only work within a single filesystem. On Unraid's classic md-array, paths under /mnt/user/... are served by shfs, which can spread files across multiple disks. The result is that hardlinks created across /mnt/user/... paths can silently fall back to copies, get broken when the mover relocates files between cache and array, or fail outright. For reliable operation on Unraid, use one of these layouts:

• Same disk: Put both source and target under the same /mnt/diskX/... path so the kernel sees one filesystem.
• Cache pool: Keep both libraries on a single cache pool with no mover involvement.
• ZFS pool (recommended): ZFS-backed pools present a single filesystem and handle hardlinks cleanly.
• Different filesystems: Switch to --copy instead of the default --hardlink. Bytes get duplicated, but the layout works.

If you used the legacy single-file script from the unraid_user_scripts branch in the past, the same constraint applied there.

This helper can also be used on other NAS systems or Linux servers — schedule it via cron for unattended syncs. Docker must be installed.

Behavior

• Hardlinks (default) — Video files are linked, not copied. Both libraries reference the same physical files on disk. Switch to --copy for cross-filesystem setups.
• Asset folders — Subdirectories (e.g., other, interviews) are processed recursively with the same materialization strategy. Note: rename your Jellyfin extras folder to other, since Plex does not recognize extras.
• Loose top-level files — Sidecar files (.nfo, posters, external subtitles, plain notes) at the top of a movie folder are synced 1:1 by default since 0.2.0. Pre-0.2.0 they were silently dropped — which made the tool unsafe for migrations. Dot-files (.DS_Store, .stversions, …) stay excluded.
• Stray items — With --delete, any file or folder in the target that has no counterpart in the source is removed. Without --delete, strays are still reported in the summary and the --json output, plus a warning at the end of the run points at --delete.
• Ignored items — Entries the scanner couldn't classify (stray files at the library root, folders whose names don't parse) are reported in the summary and the --json ignored array. They are not carried over to the target — useful to verify before deleting the source.

Library layouts

Jellyfin

This is the expected folder structure in a Jellyfin movie library. The parser relies on it being consistent:

Movies
├── A Bridge Too Far (1977) [imdbid-tt0075784]
│   ├── A Bridge Too Far (1977) [imdbid-tt0075784].mkv
│   └── trailers
│       └── A Bridge Too Far.mkv
└── Das Boot (1981) [imdbid-tt0082096]
    ├── Das Boot (1981) [imdbid-tt0082096] - Director's Cut.mkv
    ├── Das Boot (1981) [imdbid-tt0082096] - Theatrical Cut.mkv
    └── other
        ├── Production Photos.mkv
        └── Making of.mkv

Each movie must reside in its own folder, with optional subfolders for extras. Different editions (e.g., Director's Cut, Theatrical Cut) must be named accordingly.

Special filename handling

Jellyfin doesn't distinguish between editions (e.g., Director's Cut) and versions (e.g., 1080p vs. 4K). To work around this, I appended labels like "DVD", "BD", or "4K" to filenames in my personal library, ensuring the highest quality appears first and is selected by default in Jellyfin. Plex, on the other hand, supports editions natively and handles different versions via naming patterns and its internal version management. These specific labels are converted into Plex versions on the way over; other suffixes are treated as editions. The detailed mapping rules (and why DVD/BD/4k beats DVD/SDR/FHD/UHD despite the naming inconsistency) live in DEV.md.

Plex

Plex follows a more structured naming convention than Jellyfin. While Jellyfin typically appends edition or variant information using a - (space-hyphen-space) pattern, Plex supports additional metadata inside curly braces for editions and square brackets for versions or other details.

Unlike Jellyfin, Plex's naming system allows you to embed extra labels such as release source ([BluRay]), quality ([4K]), or codec ([HEVC]) directly in the filename. These labels are ignored by the default Plex scanners during media recognition, but remain visible in the interface — which makes them useful for organizing your collection without affecting playback or matching.

Note: This behavior applies to Plex's default scanner. If you use custom scanners or agents, they may treat these labels differently.

I originally started with a Jellyfin-style library and converted it to be Plex-compatible. Over time, I came to prefer Plex's more expressive naming conventions and switched my personal collection to follow the Plex format. I now use Jellyfin mainly as a fallback for long-term archival and offline use.

This is the expected folder structure in Plex format (with some demo labels):

Movies
├── A Bridge Too Far (1977) {imdb-tt0075784}
│   ├── A Bridge Too Far (1977) {imdb-tt0075784}.mkv
│   └── trailers
│       └── A Bridge Too Far.mkv
└── Das Boot (1981) {imdb-tt0082096}
    ├── Das Boot (1981) {imdb-tt0082096} {edition-Director's Cut} [1080p].mkv
    ├── Das Boot (1981) {imdb-tt0082096} {edition-Theatrical Cut} [1080p][remux].mkv
    └── other
        ├── Production Photos.mkv
        └── Making of.mkv

License

This project is licensed under the BSD 3-Clause License.

Disclaimer

This is a private project written for personal use. It doesn't cover all use cases or environments. Use at your own risk. Contributions or forks are welcome if you want to adapt it to your own setup.