How to extract subtitles from an MP4 or MOV file — free

MP4s store subtitles differently from MKVs, and most subtitle tools quietly ignore them. If you want to extract subtitles from an MP4 (or a QuickTime MOV), here’s how to get an editable file out in your browser, free.

How MP4 subtitles work: tx3g / mov_text

The MP4 container carries subtitles as tx3g tracks — you’ll also see the name mov_text, which is what ffmpeg calls the same thing. It’s a text format: each cue is stored as timed text inside the file, like SRT with a different wrapper. That’s good news — text tracks need no OCR, so extraction is instant and free.

Extract in your browser, in three steps

1. Drop your .mp4 or .mov on the PGSExtract upload page. The container is detected automatically and parsed locally — the video never leaves your machine.
2. Pick the subtitle track. Every tx3g track is listed with its language.
3. Choose a format and download. The track comes back as .srt by default, or converted to .vtt, .ass or .ssa if that’s what you need.

No account, no credits, nothing uploaded.

When your MP4 has no extractable track

Two cases look like subtitles but aren’t tx3g:

• CEA-608/708 closed captions — broadcast-style captions woven into the video stream itself rather than stored as a subtitle track. These can’t be demuxed as text; the app tells you when a file only carries captions of this kind.
• Burned-in subtitles — text rendered permanently into the picture. No tool can extract these as a track; recovering them means OCR over the video frames, which is a different problem entirely.

What about MKVs and discs?

MKVs work the same way for text tracks — see how to extract subtitles from an MKV. Disc rips with image-based tracks (Blu-ray PGS, DVD VOBSUB, broadcast DVB) need OCR instead: start with image-based vs text-based subtitles explained.

Extract your MP4 subtitles free — no account needed.