Extract subtitles from MKV and MP4 videos
Downloaded films, recorded TV and phone exports often carry their subtitles inside the video file as separate tracks you can switch on and off. This free tool lets you extract subtitles from a video — MKV, MP4, MOV, M4V or WebM — and save each track as an ordinary SRT, WebVTT or ASS file you can edit, translate, upload to YouTube or play next to the video on a TV.
It lists every embedded subtitle track with its language, title and default or forced flag, reads the cues straight from the container and writes them out with millisecond timing. The video is read in small pieces on your own device, so even a 4 GB film is never uploaded anywhere.
How to use the Extract Subtitles from Video
- Drop your video onto the box, or click it to choose a file from your computer or phone.
- Check the list of subtitle tracks. Text tracks are ticked; image-based tracks are shown with an explanation.
- Choose “Save as”: keep the original format, or convert to SRT, VTT or ASS in the same step.
- Press “Extract subtitles” and watch the progress bar — you can cancel at any time.
- Download each file, or “Download all” to get several tracks in one ZIP. A preview shows the first cues.
Extract Subtitles from Video features
Every text format in MKV and MP4
Reads SubRip (S_TEXT/UTF8), ASS/SSA, WebVTT in MKV and WebM, MP4 mov_text (3GPP timed text), WebVTT-in-MP4 and simple TTML tracks.
Keeps ASS styling
In “Original format” an ASS track is rebuilt with its script header, styles and every Dialogue line, so fonts, colours and positions survive.
Language-aware file names
Files are named like movie.eng.srt or movie.eng.forced.srt, the pattern Plex, Jellyfin, Kodi and VLC use to pick up subtitles automatically.
Compressed tracks handled
Older mkvmerge versions zlib-compress subtitle tracks; these are decompressed in the browser before conversion.
Honest about image subtitles
Blu-ray PGS, DVD VobSub and DVB subtitles are detected and explained instead of producing empty files.
Private and fast
Only the bytes that hold subtitles are read, by Galaxy of Tools’ own MP4 and Matroska parser; MP4 cues are fetched one by one using the sample table. File details come from Mediabunny (MPL-2.0) and ZIPs are built with JSZip (MIT).
Which subtitle tracks can be extracted?
| Format inside the video | Where you find it | Result |
|---|---|---|
| SubRip text (S_TEXT/UTF8) | MKV from mkvmerge, HandBrake, downloads | Exact SRT, VTT or ASS |
| ASS / SSA (S_TEXT/ASS) | Anime and fan-subtitled MKV files | ASS with styles, or plain SRT/VTT |
| WebVTT | WebM, MKV, some MP4 (wvtt) | VTT with cue settings, or SRT/ASS |
| mov_text / tx3g | MP4 and MOV from HandBrake, FFmpeg, iTunes | SRT, VTT or ASS (italic and bold kept) |
| Blu-ray PGS, DVD VobSub, DVB | Blu-ray and DVD rips, TV recordings | Not possible without OCR (images of text) |
Why some subtitles cannot be extracted
Image-based subtitles are stored as small transparent pictures, one per line of dialogue. There is no text inside them to copy, so getting an SRT file means running optical character recognition on every picture and correcting the mistakes by hand — a job for a desktop subtitle editor. This tool tells you when a track is image-based rather than silently giving you an empty file.
Subtitles that appear on screen but are not listed at all are either burned in — part of the picture itself, like those made with Burn Subtitles — or come from a separate file, or are CEA-608/708 closed captions carried inside the H.264 video stream, which are not separate tracks.
What to do with the extracted file
- Fix spelling or timing in any text editor — SRT is plain text with numbered cues.
- Convert between formats with the Subtitle Converter, or turn SRT into WebVTT for an HTML5 player with SRT to VTT.
- Translate the text and put it back as a new selectable track with Add Subtitles to Video.
- Upload the SRT to YouTube, Vimeo or a learning platform as captions.
Extract Subtitles from Video FAQ
How do I extract subtitles from an MKV file?
Drop the MKV here, keep the English (or other) track ticked, choose SRT and press “Extract subtitles”. The SRT file downloads straight away. Several tracks come as a ZIP.
Can I extract subtitles from an MP4 video?
Yes, when the MP4 or MOV contains a real subtitle track — usually mov_text (tx3g) written by HandBrake, FFmpeg or Apple tools, or WebVTT. If no track is listed, the subtitles are burned into the picture or were never in the file.
Why is my subtitle track marked as an image?
Blu-ray (PGS), DVD (VobSub) and DVB subtitles are pictures of text. Converting them to SRT needs OCR, which this browser tool does not do.
Is the timing exact?
Yes. Cue start and end times are read from the container with millisecond precision. Converting to ASS rounds to hundredths of a second, which is how that format stores time.
Is it safe to use with private videos?
Yes. The file is read by JavaScript in your browser in small pieces and is never uploaded; the page works offline once it has loaded.
Does it work on large films?
Yes. MKV files are scanned cluster by cluster and MP4 subtitle samples are read individually, so multi-gigabyte files work without loading the whole video into memory.