Karaoke Captions is a free, browser-based tool for adding animated, word-by-word captions to video. It is made and run by MD. Mezbibur Rahman Khan, an independent maker, as a sole proprietor based in Bangladesh. Because transcription runs on your own device rather than on paid servers, the free version can afford to have no watermark and no minute cap.
Why it exists
Captions that light up word by word are the standard look of short-form video, and making them meant choosing between two bad options. Free tools hand you a plain subtitle file and leave the styling to you. The polished apps animate every word, but only after your video is uploaded to their servers, and their free plans stamp a watermark on the result or stop after a few videos.
Browsers can now run a capable speech model on an ordinary laptop or phone, which removes the reason for that trade-off. If the device does the transcription, there's nothing to upload, no server bill per minute, and no reason to ration the free plan. Karaoke Captions is built on that idea.
How it's built
- On-device speech recognition: OpenAI's open-source Whisper model, run in the browser with Transformers.js, on the GPU via WebGPU where available. How the private, on-device pipeline works.
- Word-level timing: every word carries its own timestamp, so captions can highlight each word the moment it's spoken.
- One renderer: the editor preview, the style gallery and the exported MP4 are drawn by the same code, so what you see is what you export.
- Browser-native export: MP4 files are encoded with WebCodecs on your device; SRT and VTT subtitle files are generated from the same transcript.
Principles
- The free version stays useful. Unlimited videos, MP4 export and no watermark. Pro adds extra animated styles and conveniences; it never takes free features away.
- Your video is yours. It isn't uploaded, stored or used to train anything.
- Honest comparisons. The comparison pages say what competing apps do better, list the date their prices were checked, and are re-checked regularly.
Contact
Questions, bugs and feature requests go to support@karaokecaptions.com. More on the contact page.