Generate subtitles from movie audio

Updated 2026-07-02 - Verified with SubPlayer v0.5.17

What you need

• A Windows 10 or 11 PC. No graphics card is required - see the GPU section below.
• SubPlayer installed (the installer is about 263 MB; the one-movie trial needs no card; AI subtitles in public 0.5.17 require your Gemini API key).
• Audio processing itself is local. The subtitle workflow still requires an active licence or your Gemini API key; translation also requires internet.
• Clear dialogue helps: loud music, background noise and overlapping speakers lower the quality.

1. Open the movie

Go to File > "Open... (Ctrl+O)", or drag the file into the window. MKV, MP4, AVI and more are supported.

2. Wait for the engine to start

The status bar shows "Starting the engine (audio + AI model)" - this takes roughly 20-60 seconds. After that, progress is shown as "Subtitles: 3/12 chunks". You can start watching right away: subtitles are generated as you watch.

3. Pick the subtitle language

In the Subtitles menu you will see a "SubPlayer AI subtitles" track with the current language code. To get the text in another language, open Subtitle language - its own tab on the menu bar, next to Subtitles - and choose it there. Translation of the transcribed text needs an internet connection. If the movie is already spoken in your language, no cloud translation is needed, but licence or API-key access still applies.

4. Choose a quality mode

The Quality menu has three modes: "fast" (fastest), "balanced" (recommended) and "best" (highest quality, slower). Start with balanced. If you change the mode, the engine re-runs for the current movie.

Do I need a graphics card?

No. By default subtitles are generated on the CPU, and the app is tuned for it: it uses all cores and a fast int8 model.

If you have an NVIDIA card, open Settings > "Enable GPU acceleration (NVIDIA)...". This downloads a one-time package of about 530 MB and makes generation several times faster. AMD/Radeon and Intel graphics are not supported by the subtitle engine (faster-whisper accelerates only on NVIDIA CUDA). Movies that already have subtitles do not need a GPU at all - translating existing subtitles skips transcription.

5. Find the saved file

When the run finishes, the status bar shows "All subtitles ready and saved" and the file name. The subtitles are stored as an .srt file next to the movie, so the next time you open the same file they are already there. SubPlayer hides this file by default so it does not clutter the folder - turn on Settings > "Show .srt files next to the video" if you want to see or copy it in File Explorer. If you switch the language later, the transcription is reused from cache - only the translation runs again.

What if something goes wrong?

The text has mistakes in names or quiet scenes

Names, whispering, several people talking at once and background noise are the usual weak spots of speech recognition. Expect a few odd lines; you can correct them in any text editor.

Generation feels slow

Time depends on the CPU or GPU, the movie length and the quality mode - there is no universal number. Try the "fast" quality mode, or enable GPU acceleration if you have an NVIDIA card.

The engine reports an error

Open Help > "Open log (diagnostics)" to see what happened. "Send diagnostics to support..." is optional and may include the licence email, system details and redacted recent log lines. Review the preview before sending.

Subtitles are not generated anymore

The trial covers one movie and needs your own Gemini API key for AI subtitles in the current public build. After the trial, the movie still plays, but subtitles are not generated until you subscribe. Open the License menu and choose Activate.

Frequently asked questions

Does it work offline?

Audio processing runs locally, but the subtitle workflow still needs an active licence or your Gemini API key. Translation also needs internet.

Does my audio leave the PC?

No. The movie and its audio are processed on your computer. If you translate, only the subtitle text is sent.

How long does a movie take?

It depends on the CPU or GPU, the movie length and the quality mode - there is no universal number. Translating a movie that already has subtitles is much faster because transcription is skipped.

Are the subtitles burned into the video?

No. The video file is not modified. Subtitles are shown during playback and saved as a separate .srt file.

Can I switch the subtitle language afterwards?

Yes. Pick another language under Subtitle language - the transcription is reused from cache and only the translation runs again.

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