Ondine

The step you run before Plex scans.

Plex, Jellyfin and Kodi show you a beautiful library, but only when the files are already named and filed properly. When they are not, those servers give up: the episode shows up as «Unknown», the film gets mistaken for another one, or it simply never appears. Ondine is the step you run before.

Desktop app for Windows · terminal tool for Linux, macOS and Windows

Español · English

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Forty-four seconds · plays on ondine.hdglabs.com

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Three things, and all three raise the quality of the data in your library:

• Compress, so it fits. Typically 80 to 90% smaller while keeping the picture where it should be, using hardware acceleration. Before it starts it shows you a forecast of the final size, and if you want that sharper it can measure it for real by encoding short samples. It also knows how to drop dubs and subtitles without re-encoding: a 155 MB episode falls to 134 MB in 0.6 s, with the video identical bit for bit.
• Organise, so the server recognises it. It matches every episode in a folder against a catalogue and proposes its canonical name. It understands that one episode can carry several stories inside (E1a, E1b, E1c), knows how to split it into separate files, and tells you which episodes you are missing.
• Trim, to remove what does not belong. Split a video into several, or cut a chunk out of it, without opening an editor.

It never touches the originals unless you explicitly ask it to, and even then they go to the recycle bin, never to permanent deletion. Everything happens on your machine: it sends your files nowhere.

What changed in each version: CHANGELOG.md · Where it is going: ROADMAP.md.

What it looks like

The interface is currently in Spanish. English is on the way; the screenshots below are the real app, not mock-ups.

Compress scans a whole folder and lists the tracks of every video: codec, duration, audio and subtitle languages. Then it compresses in batch, and the panel on the right forecasts the final size and the saving.

Organise compares the files in a folder against an episode catalogue and proposes a name for each one, grouped by season. Colour tells you what to trust, and nothing gets renamed until you approve it.

Trim splits a video into several or cuts a piece out. Each segment comes out as its own file, and the original is only removed if all of them succeed. When the name carries two titles, the second segment names itself.

What it can do

• Real batches. Explorer-style selection in the table: band drag, Ctrl/Shift+click, Ctrl+A. Whatever is selected gets processed. Del removes from the list without touching the file, and right click opens a menu with more options.
• Forecast and measurement. Live estimate of size and saving with a quality-versus-saving reading. The Measure with a sample button encodes three fragments and gives you the real figure, calibrating the rest of the list along the way.
• It does not get stuck. If the disk fills up it pauses instead of cancelling or hanging, and carries on by itself as soon as you free space, keeping the queue intact.
• Languages and subtitles. It detects the tracks, sets your preferred language as the default one, and drops the ones you do not want to keep.
• PowerRename-style output renaming: search and replace with regular expressions, counters, date variables and text casing, with a live preview.
• Ten-second preview with the current settings, so you can check before launching the batch.
• Organise: catalogue matching and renaming. It checks a folder of episodes against a catalogue (JSON) and proposes the canonical name for each, identifying them by title even when the filename arrives with numbering and download clutter. It marks the state of every file (clean, changed or conflicting) and applies in bulk the ones it identifies confidently; anything doubtful is left for you to decide, and it never invents. Sort the columns by clicking a header.
• Trim: split and cut. Divide a video into several segments or cut a piece out, to separate episodes stuck together or remove intros, with a timeline preview.
• Presets and preferences per tab, and automatic updates from GitHub.

Installing

Windows, desktop app

1. Download the installer from the Releases page: Ondine-Setup-X.Y.Z.exe.
2. Run it. It installs for your user only (no administrator prompt) and creates a Start menu shortcut, and optionally one on the Desktop.
3. The installer is not signed, so Windows SmartScreen may warn you: click More info → Run anyway.

FFmpeg is the only dependency, and the installer detects it automatically. If you do not have it, it offers to download and install it alongside the app. There is nothing to configure.

Linux and macOS, terminal

The graphical interface uses WPF, which only exists on Windows. For every other system there is ondine, which shares exactly the same engine. Download the package for your platform from Releases and unpack it:

tar xzf ondine-linux-x64.tar.gz     # or linux-arm64, macos-arm64, macos-x64
./ondine --help

It is a single self-contained binary: you do not need to install .NET. It ships as .tar.gz because that preserves the execute permission, which a bare file loses when downloaded.

On Windows, the terminal tool downloads directly as ondine-windows-x64.exe, uncompressed. Careful: that is the CLI, which is a different thing from the Ondine-Setup-X.Y.Z.exe installer, which is the desktop app.

It needs ffmpeg and ffprobe on the PATH (apt install ffmpeg, brew install ffmpeg).

Using it

Desktop app

1. Source: pick a folder, or individual files. With Subfolders ticked, it walks into the seasons.
2. Analyse: lists the videos with size, duration, codec and the audio and subtitle languages it detected.
3. Adjust the options (they all have a sensible default) or pick a preset.
4. Select the videos and hit Compress selection. You get live progress, with Pause and Stop available at any moment.

The main language (Spanish by default) is marked as the default audio track; the languages you do not pick are dropped to save space.

Terminal

# Compress a whole season to 720p MP4 with 128 kbps audio
ondine comprimir series/ -r --formato mp4 --alto 720 --audio 128 -o compressed/

# See what tracks each video carries
ondine analizar series/ -r

# Measure how much it will really take, without compressing the whole thing
ondine medir episode.mkv --alto 720

# Compress while renaming the output with a counter
ondine comprimir *.mkv --regex --buscar "^" --reemplazar 'S01E${padding=2;start=1} - ' --enumerar

ondine --help lists every option.

The command names and flags are in Spanish for now. They are part of the same translation pass as the interface.

Automatic updates

The app checks GitHub for a newer version on startup. If there is one, hitting Update now downloads the installer, runs it and closes the app to complete the update, which replaces the previous version in place. You can also check by hand with Check for updates.

Development

Requirements: .NET 9 SDK and Inno Setup 6 (winget install JRSoftware.InnoSetup).

# Run the app in development
dotnet run --project src/Ondine

# Run the terminal tool
dotnet run --project src/Ondine.Cli -- --help

# Build the whole installer (icon + self-contained .exe + Inno installer)
pwsh -File build.ps1
# -> installer/Output/Ondine-Setup-<version>.exe

Publishing a release

Everything builds in the cloud, with no local dependencies:

1. Add the version section to CHANGELOG.md (## [X.Y.Z] - YYYY-MM-DD).
2. Bump <Version> in both .csproj files (src/Ondine and src/Ondine.Cli).
3. git tag vX.Y.Z && git push --follow-tags.

GitHub Actions checks the CHANGELOG contract first, that the section exists, that the versions match and that the categories are valid, and only then builds the Windows installer and the terminal binaries for Linux, macOS and Windows, attaching everything to the Release. If the contract is not met, nothing gets published.

Layout

Folder	What it is
src/Ondine/	C#/WPF app. Engine.cs is the engine (FFmpeg); the rest is interface and auto-update.
src/Ondine.Cli/	Cross-platform terminal tool. It links the engine sources, it does not copy them.
installer/	Inno Setup script.
web/	The site at ondine.hdglabs.com, on Astro.
spot/	The forty-four second spot, built as HTML compositions.
make-icon.ps1	Generates the icon with GDI+.
build.ps1	Builds everything end to end.
legacy/	The original PowerShell version the project was born as.

The graphical interface is Windows only because it uses WPF, which has no runtime on Linux or macOS. The engine (Engine, Estimator, RenameRule) is portable, and that is exactly what the terminal tool reuses. Bringing the full interface to Linux and macOS would mean porting it to Avalonia.

How it works

• It detects the tracks with ffprobe and reorders the audio to put your preferred language first and mark it as default.
• It picks whichever hardware encoder is available (Intel QSV, NVIDIA NVENC, AMD AMF) or falls back to the CPU (libx265).
• It skips what is already compressed (HEVC/AV1 at a low bitrate) and files that are still downloading.
• It always writes to a temporary file and only moves it to the destination when it finishes cleanly, so an interruption never leaves a half-written video passing itself off as a good one.

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It used to be called ShrinkStudio.