Add subtitles to video without uploading it

Three ways to add subtitles to a video

There are three common ways to put subtitles on a video. The right one depends on where the video will be watched.

• A subtitle file next to the video.

  A small .srt, .vtt or .ass file that the player loads with the video. The video itself doesn't change. This is what you upload to YouTube or a course platform, and what players like VLC open.

• A subtitle track inside the video.

  The subtitles travel inside the MP4 or MKV file, and the viewer turns them on or off in the player. One file can hold several languages.

• Burned-in captions.

  The text is drawn into the picture. Everyone sees it, in every app, but no one can turn it off. It's a common choice for short clips on TikTok, Reels and Shorts.

Wolfcaps does all three. Subtitle files and tracks come from Video → subtitles. Burned-in captions come from Reels & Shorts: see captions for Reels, TikTok and Shorts.

How to add subtitles to a video with Wolfcaps

1. 1Open Video → subtitles and drop your video (MP4, MKV, MOV, WebM, AVI, TS/MTS, WMV or FLV). If it's on your phone, click Send from your phone and scan the QR code.
2. 2In Transcribe this video?, choose the spoken language (English, Hebrew or Russian) and Balanced or Best. If the video already contains subtitles, Wolfcaps finds them and uses them instead.
3. 3Wait while the AI writes the subtitles on your computer. You see an estimate before it starts.
4. 4Check the lines. Click one to hear it and fix the text, or open the Full editor to adjust timing on a waveform.
5. 5Optional: click Translate… to add a second language.
6. 6Click Export… and choose Subtitle file or Video with subtitles.

For Video with subtitles, tick the languages to include and choose which one is shown when the video opens. You can also choose none, so viewers turn the subtitles on themselves. Then pick MP4 or MKV and save.

Your video and sound are copied unchanged. Nothing is re-encoded, so it's fast and there's no quality loss.

MP4 or MKV?

Both hold the same video, with the subtitles inside as tracks. The difference is where they play and how the subtitles look.

• MP4.

  Plays almost everywhere. Its subtitles show in QuickTime, on iPhone, in VLC, mpv and most TVs. Each player shows them in its own plain style.

• MKV.

  Holds any video and audio. Its subtitles show in VLC, mpv, Plex and Kodi, and they keep the subtitle style you picked. Apple's built-in apps can't open MKV.

Some videos can't go into an MP4 without re-encoding. When that happens, Wolfcaps tells you, and you choose MKV instead.

Choose how the subtitles look

In Video → subtitles you can pick a subtitle style: Netflix, YouTube, Cinema, Classic yellow or TV box, and a font. Or keep Player default and let each player use its own look.

These styles are drawn by the player, not burned into the picture, so viewers can still turn the subtitles off. They're kept in MKV videos and ASS files. MP4 videos and SRT files always show the player's own look.

Using a subtitle file instead

Sometimes a separate file is the better choice. A subtitle file is tiny, you can edit it in any text editor, and video platforms ask for one when you add subtitles to a video you upload. Many desktop players, VLC for example, load an .srt automatically when it has the same name as the video and sits in the same folder. The SRT generator page explains the formats in more detail.

What you need

• A computer with Chrome, Edge, Brave or another Chromium browser, or Safari 26 or newer on a Mac, and a GPU the browser can use (WebGPU). Firefox, iPhone and iPad aren't supported yet.
• Speech in English, Hebrew or Russian. Other spoken languages aren't supported yet, but you can translate the subtitles into 20 languages.
• A one-time model download of about 1.6 GB (2.1 GB for Hebrew Best), kept in your browser.