How to add subtitles to a video
Captions written from the speech and burned into the picture, without a watermark or a length cap. Here is how, and a tool that does both steps on your own device.
Soft subtitles vs burned-in captions
A subtitle file (SRT or VTT) is a separate track a player can turn on or off, the way Netflix or YouTube captions work. Burned-in (or "hardcoded" and "open") captions are drawn directly into the video frames, so they show on any player, including Instagram, TikTok and a video sent as a plain file, with no viewer setting to toggle. Social platforms need the burned-in kind because their own players do not read an attached SRT reliably.
Editing apps and their free-tier catches
CapCut, Premiere Pro and DaVinci Resolve can all auto-caption and burn in subtitles. CapCut's free tier is the most accessible on a phone, but exporting without its watermark, and some caption styles, sit behind CapCut Pro. Premiere and Resolve have no watermark but need buying or learning a full editor for what is otherwise a single, short task.
Web-based auto-caption tools
Kapwing, VEED and similar web tools auto-caption from the speech and are quick to use, but most cap free exports at a short length (often under a minute), add a watermark, or both, with the unlocked version behind a monthly subscription.
Captioning without a watermark or length cap
Stayput's add subtitles to video tool writes the captions itself, using the same on-device Whisper model as the transcribe tool, or burns in an SRT or VTT file you already have, and draws them into the video with a choice of three caption styles. It runs entirely in the browser tab, so there is no length cap beyond what your device can hold in memory, no watermark, and no upload of the video.
Questions
What is the difference between subtitles and captions burned in?
Subtitles are a separate file a player can switch on or off. Burned-in captions are part of the video image itself, so they show up everywhere, which is what most social platforms need.
Can I add subtitles to a video for free with no watermark?
Yes, with a tool that processes the video in your browser rather than a server, since nothing is uploaded and no watermark is added.
Do auto-captions need an internet connection?
A browser-based tool works offline after it has downloaded its speech model and engine once; a cloud-based captioning site needs a connection for every video.
Can I burn in subtitles I already wrote as an SRT file?
Yes. Stayput's add subtitles tool accepts an existing SRT or VTT file and burns those exact captions into the video instead of generating new ones from the speech.