Installing dependencies
AI Subtitle Studio doesn't bundle every tool it uses into the app itself — instead it downloads and manages a small set of well-known open-source tools on demand. You install and update them from Settings → Dependencies.
The six tools
| FFmpeg | Video/audio conversion, stream extraction and encoding. Required for scanning videos and extracting subtitles. |
|---|---|
| FFprobe | Probes video files for streams, duration and metadata. Installed together with FFmpeg — there's no separate install button. |
| Whisper.cpp | The AI speech-recognition engine used for transcription. Installing this gets you the engine; you separately download model sizes in Transcription Models. |
| FFsubsync | Synchronizes subtitles with audio using speech alignment. Powers the Auto-Sync feature in the editor. |
| Subtitle Edit (OCR) | Windows-only external tool used by an optional OCR shortcut right after extraction — shows as "Not Available on macOS" on Mac. It is not required for OCR in general: converting image-based subtitles (Blu-ray SUP, DVD SUB/IDX) to text is handled separately by the Convert screen's own bundled OCR engine, which works on both Windows and macOS with no external tool. |
| mkvextract | Extracts subtitle tracks from Matroska (MKV) files reliably. Part of the MKVToolNix suite. Optional — doesn't block the app from being "Ready." |
Installing and updating
Each tool has its own card showing its install status (a green "Installed" or grey "Not Installed" badge) and version. For an uninstalled tool, click Download & Install. Once installed, the same button becomes Update, alongside two more icon buttons:
- A folder icon to reveal where the tool is installed on disk.
- A trash icon to remove it — click once to arm a confirmation (turns red with a warning icon for 3 seconds), click again to actually delete.
Downloads show a live progress bar with a percentage and status message (e.g. "Downloading…", "Extracting…").
Whisper.cpp has a version picker
Before installing Whisper.cpp, a Version dropdown lets you pick a build variant appropriate for your hardware (for example, a Metal build on Apple Silicon, or a CUDA build on Windows with an NVIDIA GPU). Once installed, the card shows a small CUDA/Metal/CPU tag next to the version so you can see which one is active. If no variants are available for your platform (e.g. some Intel Macs), the dropdown explains that instead.
What happens if something is missing
If a core dependency (FFmpeg, Whisper.cpp, or FFsubsync) isn't installed, you'll see an amber "Setup Required" banner at the top of the Dependencies screen listing exactly what's missing, and similar banners appear on the Dashboard and Edit Subtitles screens when you try to use a feature that needs them. The footer status bar at the bottom of the Dependencies screen also summarizes this as "Ready" (green) or "Missing: X, Y" (amber).
Where files are stored
An info box at the bottom of the Dependencies screen shows the exact Storage Location path where all downloaded tools live on your machine — useful if you ever need to inspect, back up, or manually clean up the installation.