SUB to SRT Converter — Frame Times Made Readable
Convert frame-based MicroDVD .sub files to timed SRT — pick the frame rate (23.976 default) and convert in-browser.
Quick answer: Drop a MicroDVD .sub file, pick the frame rate the video was mastered at (23.976 fps is the usual default), and download an .srt with real timestamps — frame numbers ÷ fps become seconds.
Drop a subtitle file here, or browse — it stays on your device
Output: SRT (.srt)
| Input | MicroDVD .sub — {startFrame}{endFrame}text, | for line breaks |
|---|---|
| Output | SRT with real timestamps |
| Frame rates | 23.976 (film) · 24 · 25 (PAL) · 29.97 (NTSC video) |
| Rule | time = frame ÷ fps; wrong fps = progressively drifting sync |
| Privacy | Runs in the browser; no upload |
What this tool does
The .sub extension usually means MicroDVD: a bare-bones format where each cue is written as {123}{456}text — the first number is the first frame the line shows on, the second the last, and the pipe character splits lines. Frames are not times: to convert, you divide by the frame rate the release was mastered at. Pick 23.976 for film-sourced releases, 25 for PAL broadcasts, 29.97 for NTSC video. The right frame rate converts a perfectly synced subtitle; the wrong one produces drift that grows over the film — a few seconds early at the start, minutes by the end. This page does the arithmetic in your browser and shows the resulting cue table.
Common uses
- Old movie rips shipped with MicroDVD .sub files need SRT for modern players
- A subtitle archive standardises on SRT
- Diagnosing drift: re-convert with a different frame rate to test
Why frame rate matters this much
A 90-minute film at 23.976 fps spans about 129,000 frames. Convert with 25 instead and every timestamp shrinks by about 4% — the first cue appears roughly right, but by the hour mark it is more than two minutes off. This is why MicroDVD files were always distributed with an fps note, and why this converter makes the frame rate a visible choice rather than a silent assumption.