Add subtitles to a video with AI
Without uploading it anywhere. You see it on your own frame before deciding, and the video comes out with no watermark.
Updated: October 2026 · 6 min read
To add subtitles to a video with AI without uploading it anywhere: install AppGrabbit, open Download › Subtitles with AI, drop the video or paste its link and click Get subtitles (1 credit). You pick the style on a real frame of your video, free, and Make the video leaves them burned in, with no watermark. Everything runs on your PC. 1 credit · burning: Pro
Three ways to add subtitles, and which one fits
There are three roads. Typing them by hand in an editor: exact, but an hour per ten minutes of video. A website with AI: fast, but you upload the video, accept the watermark or pay, and the timing usually goes per sentence. An app on your PC: the engine transcribes right there with the timing of every word, you see the result on your own frame before deciding, and the video comes out clean. This guide is the third road.
How AppGrabbit does it
From a link, the app downloads the full video; from a file, it reads it where it is. It pulls the audio out with FFmpeg and transcribes it with Whisper on your PC asking for the timing of every word. It builds the subtitles in two lines of up to 42 characters, cut on silences and at the end of each sentence, and shows you a real frame with them on it: Classic at the bottom in white with an outline, Box on a black box, Center large with the spoken word in yellow. If you like it, it burns them with FFmpeg and libass using the Poppins font that ships inside the app; the MP4 comes out at the original size.
How long it takes and how tight the sync is
- Transcribing — with an NVIDIA card, about 30 seconds per 10 minutes; CPU only, about 2 minutes per 10.
- Burning — a 51-second portrait video takes about 9 seconds.
- Sync — measured on the final video, a subtitle appears about 150 milliseconds before the voice; the burn adds not a single frame.
- Wrong words — about 5 to 8 in 100, mostly names: you see them in the preview before paying.
AppGrabbit against the other ways
| AppGrabbit | By hand in an editor | Websites with AI | CapCut | |
|---|---|---|---|---|
| Time for 10 minutes of video | A minute or so | An hour | Minutes, plus uploading | Minutes |
| Your video never leaves your PC | ✓ Never | ✓ Never | ✗ Goes to their servers | ~ Depends on the version |
| Watermark | ✓ Never | ✓ No | ✗ On free | ~ On free, by feature |
| Timing of every word | ✓ Yes | ~ If you set it | ~ Sometimes | ✓ Yes, on Pro |
| Cost | Get subtitles: 1 credit (5 free a month) · preview: free · Make the video: Pro $8.99/mo or 7-day pass $3.99 | Your time | Free minutes, then a subscription | Auto captions on Pro, about USD 20 a month |
Step by step
- 1Install AppGrabbit for Windows — Download the free installer (everything included). Windows will say it protected your PC because the installer is not code-signed: click More info, then Run anyway.
- 2Open Download › Subtitles with AI — Paste the video link (YouTube, TikTok, Instagram, Facebook, X, Twitch) or drop your file (mp4, mkv, mov, webm). From the Library, any video has “Subtitles with AI” in its ⋯ menu.
- 3Click “Get subtitles” (1 credit) — The first time, the app gets the AI engine ready on your PC (a one-time download) and carries on by itself. Out come the .srt, the .vtt and the .txt in the Subtitles folder, timed word by word.
- 4Pick the style on a real frame (free) — Classic (two lines at the bottom), Box (on a black box) or Center (three or four large words, the spoken one in yellow). “Previous / next moment” shows another sentence.
- 5Click “Make the video” (Pro or the 7-day pass) — The subtitles are burned into the video, at its size and with no watermark. The MP4 is named after your video plus “_subtitulos” and lands in the Library.
Frequently asked questions
Getting the subtitles (.srt, .vtt and .txt) costs 1 credit; Free comes with 5 a month. Previewing them on your video, in the three styles, is free. Burning them in (“Make the video”) is for Pro (USD 8.99 a month) or the 7-day pass (USD 3.99, no renewal). There is never a watermark, not even on Free.
Yes: drop it in (mp4, mov, mkv, webm). If it is on TikTok, Instagram or YouTube, paste the link and the app downloads the full video to subtitle it.
Classic for landscape videos and classes; Box if the background moves a lot; Center for Reels, TikTok and Shorts, with the spoken word in yellow.
It is re-encoded in H.264 at the same size with AAC audio; on a phone or social video you will not notice.
The .srt and .vtt are text: fix them in Notepad and use them on YouTube or in your editor. The video the app makes uses what the engine transcribed; a wrong word (about 5 to 8 in 100, mostly names) shows in the preview before you pay.
The spoken one; the engine detects it and you can pin it before starting. It does not translate: a video in another language is a different job.
The app tells you and gives the credit back. A music-only video gets no made-up text.
Nothing. The video stays on your PC: the AI engine (Whisper, whisper.cpp) runs on your computer, on your NVIDIA card if you have one or on the CPU if not, and FFmpeg burns the subtitles right there.
Related guides
Add subtitles to your video, on your PC
Windows 10/11 · Get subtitles: 1 credit, 5 free a month · Make the video: Pro or 7-day pass