video-subtitle-extractor
A video subtitle extractor pulls subtitle tracks (SRT, ASS, VTT) embedded in container formats like MKV and MP4 into standalone subtitle files, letting you edit, translate, re-time, or import them into other video tools. The ZTools Video Subtitle Extractor runs entirely in the browser via FFmpeg.wasm, supports MKV / MP4 / MOV / WebM inputs, lists every subtitle track with language metadata, lets you pick which to extract, and outputs SRT (universal) or VTT (web-friendly) files saved locally.
Use cases
Editing subtitles
Found a typo or want to fix translation. Extract the subtitle track; edit in any text editor (it's plain text); re-import into the video.
Re-timing for re-encoded video
After re-encoding a video at a different frame rate, original subtitles drift out of sync. Extract, re-time using a subtitle editor, re-embed.
Subtitle translation
Translate the subtitle file into another language (manually, or via translation API). Single text file is far easier to translate than handling video inline.
Standalone subtitle archive
Some media servers (Plex, Jellyfin) prefer standalone .srt files alongside videos. Extract once, store separately for cleaner library structure.
How it works
- Upload video — Drag-drop or pick. Tool inspects container metadata to enumerate subtitle tracks.
- Pick subtitle track — List shows index, language code (eng, spa, jpn), codec, and forced flag. Most videos have 0-3 subtitle tracks; some have 10+.
- Choose output format — SRT: universal, plain text, fully featured. VTT: web standard for HTML5 video, similar to SRT with optional styling. Pick based on destination.
- Extract — FFmpeg.wasm reads the track, demuxes the subtitle stream, writes the chosen format.
- Download — Subtitle file saves locally. Open in any text editor or import into video tools.
Examples
Input: MKV with 3 subtitle tracks (English, Spanish, Japanese)
Output: Pick English; download English.srt. Re-run for other languages.
Input: MP4 with embedded VTT subtitles
Output: Direct extraction to .vtt; no transcoding needed.
Input: MKV with ASS subtitles (anime style with positioning)
Output: Convert to SRT (loses positioning) or extract as ASS to preserve all styling.
Frequently asked questions
What if my video has no embedded subtitles?
You cannot extract what is not there. For videos without embedded subtitles, use speech-to-text on the audio or AI subtitle services to generate them.
What is the difference between SRT and VTT?
SRT: text-only, universal across players. VTT: web standard, supports CSS styling, used by HTML5 <track>. Functionally similar for most content.
How do I re-embed edited subtitles?
Use a tool like MKVToolNix (desktop) to remux the video with the new subtitle file. The browser tool extracts; remuxing requires desktop.
Why are subtitles slightly off-sync?
Frame-rate mismatch between subtitle timing and video playback. Most subtitle editors have re-time tools (shift all by N seconds, or re-time at start + end).
Is the video uploaded?
No — FFmpeg.wasm processes in-browser. Privacy by design.
Can I extract burned-in subtitles?
No — burned-in subtitles are part of the video frames, not a separate track. Extracting them requires OCR over each frame; specialised tools exist for this.
Tips
- Inspect track metadata first — language tags help when there are multiple options. Extract the right track to save time.
- SRT is the safest target format for editing; convert to VTT only when serving HTML5 video.
- For style-rich subtitles (anime, opera), preserve as ASS / SSA — converting to SRT loses styling.
- After editing, validate the timing in a subtitle editor — most editors flag overlap, gap, or out-of-bound timestamps.
- For batch extraction across many files, scripted FFmpeg on desktop is faster than per-file browser uploads.
Try it now
The full video-subtitle-extractor runs in your browser at https://ztools.zaions.com/video-subtitle-extractor — no signup, no upload, no data leaves your device.
Last updated: 2026-05-05 · Author: Ahsan Mahmood · Edit this page on GitHub