How to add subtitles to a video on Mac (local, no upload)
Updated 2026-06-11 · Runs locally — nothing uploaded
Adding captions usually means uploading your video to some web service — not great for interviews, internal footage, or anything private. It doesn’t have to be that way.
FFmix burns an existing SRT into your video, or transcribes the speech for you with Whisper running locally (Pro). Either way the audio and video stay on your Mac, and you can choose to hardcode the captions or just export the .srt.
Steps
- 1 Drag your video into FFmix.
- 2 Either point it at an .srt file, or auto-transcribe with local Whisper (Pro).
- 3 Confirm and click Start — the captions are burned into the video.
Advanced: the real ffmpeg command
This is exactly what FFmix runs. Copy it, tweak it, or just use the one-click preset.
ffmpeg -i input.mp4 -vf "subtitles=filename='subs.srt':force_style='FontSize=24,Alignment=2'" -c:a copy subtitled.mp4Drop a file and go — all local, nothing uploaded.
FAQ
Can FFmix generate subtitles automatically?
Yes. It runs Whisper locally to transcribe speech into an SRT (a Pro feature). Your audio is never uploaded — transcription happens entirely on your Mac.
What's the difference between burning and a separate SRT?
Burning hardcodes the captions into the picture so they always show. FFmix can also export just the .srt if you'd rather keep them as a toggleable track.
Is anything sent to a server?
No. Both transcription and burn-in run locally through the bundled engines; nothing leaves your Mac.