Convert MicroDVD SUB to SRT
Some old .sub files store text with frame numbers instead of times. Pick the frame rate and get a normal SRT file.
🔒 Runs in your browser. Your files and text are not uploaded.
How to use the SUB to SRT Converter
- Open your .sub file in a text editor. If you can read lines like
{1200}{1295}Helloit is the text-based MicroDVD format and this tool can convert it. If it looks like binary gibberish, see the section below. - Drop the file onto the converter.
- Leave the frame rate on Auto to read it from the first line (
{1}{1}23.976), or choose the frame rate of your video. - Convert and download the .srt. If the timing drifts, convert the frame rate again with the FPS converter.
Two completely different “.sub” formats
The extension .sub is used for two unrelated things:
| MicroDVD / SubViewer (text) | VobSub (image) | |
|---|---|---|
| Content | Text with frame or time codes | Pictures of subtitles ripped from a DVD |
| Companion file | None | An .idx file with the same name |
| Size | Tens of kilobytes | Megabytes |
| Convert in browser? | Yes, with this page | No — needs OCR software |
If you have a .sub plus an .idx, you need an OCR tool such as Subtitle Edit or SubRip to recognise the text from the images. A browser tool cannot do that reliably.
Frame numbers and frame rates
MicroDVD stores {start_frame}{end_frame}text. To get seconds, divide the frame number by the frame rate: frame 1200 at 25 fps is 48.0 seconds, but at 23.976 fps it is 50.05 seconds. Choosing the wrong rate makes the subtitles slowly drift apart from the speech. Many files declare the frame rate in a first line like {1}{1}25.000; the converter reads it automatically.
Formatting codes
A vertical bar | in MicroDVD means a line break and becomes a real line break in SRT. Codes like {y:i} (italic) and {y:b} (bold) are turned into <i> and <b>. Colour and font codes are removed.
Troubleshooting
- Subtitles start too early or too late — try another frame rate (23.976, 24, 25).
- Accents are wrong — the file is probably in a legacy encoding; run the encoding fixer.
- Nothing converts — the file may be VobSub or another format; open it in a text editor to check.
Frequently asked questions
How do I know whether my .sub is text or VobSub?
Open it in Notepad. Readable lines with curly-brace numbers mean MicroDVD (text). Unreadable binary data, usually with an .idx file next to it, means VobSub (images).
Which frame rate should I choose?
Use the frame rate of the video the subtitles were made for. Films are usually 23.976 or 24 fps, PAL video 25 fps and NTSC video 29.97 fps.
Can this tool OCR VobSub subtitles?
No. Recognising text from pictures needs OCR software; a browser tool cannot do it reliably.
What about SubViewer .sub files with 00:00:01.00 times?
Those use real time codes. If they are detected as such, they are converted without needing a frame rate.
Will the subtitles still drift after conversion?
If the video has a different frame rate from the one chosen, yes. Use the FPS converter to correct the ratio.
Is my file uploaded?
No. It stays in your browser.