Video to Subtitles Converter
Create subtitles for a video file, entirely on your own device.
File
Result
Your converted file will appear here.
About the Video to Subtitles converter
Captions make a video searchable, accessible and watchable with the sound off — which is how most social video is actually consumed. Producing them usually means paying per minute or handing your footage to a transcription service.
This converter reads the audio track out of your video and recognises the speech locally. Unreleased footage stays on your machine, which is the part most services cannot offer.
Only the audio is read
The video stream is ignored entirely — nothing is decoded, re-encoded or uploaded. That is why a large file starts processing immediately rather than after a long upload.
Any container your browser can play works: MP4 and MOV with AAC audio, WebM with Opus or Vorbis, and usually MKV.
What to expect from the accuracy
Clear single-speaker audio — a lecture, a podcast, a voice memo — transcribes well, and the base model is noticeably better than tiny at proper nouns and technical terms.
Accuracy falls with background noise, strong accents, crosstalk and music. The model does not label speakers, so an interview comes out as continuous text rather than a dialogue.
Treat the output as a strong first draft. For anything published or legally significant, read it against the audio before you rely on it.
Using the subtitles
Save as WebVTT to attach a track to an HTML5 video with `<track src="captions.vtt" kind="subtitles">`. Save as SRT for video editors, social platforms and desktop players.
If the result is slightly out of step with the picture, the Subtitle Sync tool will shift every cue by a fixed offset.
How it works, and where the model comes from
Your browser decodes the audio, resamples it to the 16 kHz mono that Whisper expects, and hands it to the model running in a background worker. Nothing is uploaded, so no server ever holds your recording.
The model itself is a few dozen megabytes and is downloaded the first time you use the tool, then kept in your browser's cache. Later visits start immediately and work with no network connection at all.
Where WebGPU is available — Chrome, Edge and recent Safari — recognition runs on the graphics card and is typically faster than real time. Elsewhere it falls back to the CPU, which works but is several times slower.
Frequently asked questions
Is my recording uploaded anywhere?
No. The model runs inside your browser tab, so the audio never leaves your device. The only network request is the one-time model download, and self-hosted model files mean even that does not reveal what you are transcribing.
How long a file can I transcribe?
Long files work — the audio is processed in 30-second windows with overlap — but it takes real time on your own hardware. An hour of audio is comfortable with WebGPU and slow without it. Leave the tab open while it runs.
Do I have to download the model every time?
No. It is stored in your browser's cache after the first use, so later visits start straight away and work offline. Clearing your browser's site data removes it, and it downloads again next time.
Can I burn the subtitles into the video?
Not here. This produces a subtitle file to attach alongside the video. Burning them in means re-encoding the video, which is a much heavier job.