Transcribe audio and video files locally on your Mac (with SRT/VTT subtitles)
OpenWhisp can transcribe audio and video files on a Mac completely offline: add an MP3, MP4, M4A, WAV, or WEBM and it runs your on-device engine, showing a live per-file queue. Long files are chunked automatically, and finished transcripts export to plain text, SubRip (.srt), or WebVTT (.vtt) with timestamps. Set a watch folder and dropped media transcribes itself.
Live dictation is only half of speech-to-text. The other half is the pile of recordings you already have: a meeting recording, a lecture, a podcast episode, a screen-capture video you need captions for. Most tools that transcribe those files upload them to a server. OpenWhisp does it entirely on your Mac.
Drop in a file, get a transcript
- Open Settings › File Transcription and add one or more media files — MP3, MP4, M4A, WAV, WEBM, and more.
- OpenWhisp decodes each to 16 kHz audio and runs it through your on-device engine, one file at a time.
- A live queue shows each file’s progress: Queued → Loading model → Transcribing → Done. Long files are chunked automatically.
- Export a finished transcript as plain text, .srt, or .vtt — the subtitle formats carry chunk-level timestamps.
Subtitles, generated on device
The SubRip (.srt) and WebVTT (.vtt) exports make this a genuine local captioning tool. Feed it a video’s audio and you get a timestamped subtitle file you can drop straight into a video editor or a web player — without sending the footage to anyone. For sensitive recordings (interviews, internal meetings, anything under NDA), that’s the difference between “can’t use a transcription service” and “done in the background.”
Set it and forget it: watch folders
You can point OpenWhisp at a watch folder: any media dropped into it transcribes itself automatically (it waits for a file to finish copying before starting). Route your recorder’s output folder there and transcripts appear without you lifting a finger.
Why local matters here
Cloud transcription services charge per minute and require you to upload the file — a non-starter for long or confidential recordings. Because OpenWhisp runs Whisper-class models on your own hardware, batch transcription is free, works offline, and keeps every file on your machine. It’s the same engine behind live dictation, pointed at files instead of your microphone.
Frequently asked questions
- Can I transcribe a video or audio file on a Mac without uploading it?
- Yes. OpenWhisp transcribes MP3, MP4, M4A, WAV, WEBM and other media files entirely on-device — the file never leaves your Mac. Add files in Settings › File Transcription and export the result as text, SRT, or VTT.
- Can OpenWhisp generate subtitles (SRT/VTT)?
- Yes. Finished transcripts export to SubRip (.srt) and WebVTT (.vtt) with chunk-level timestamps, so you can caption a video locally.
- Can it transcribe a folder of files automatically?
- Yes. Set up a watch folder and any media dropped into it is transcribed automatically once the file finishes copying.
Try OpenWhisp
Free, open source, and 100% on-device dictation for Apple Silicon Macs.