SyncMySubsConvert SUB to ASS
Convert a .sub subtitle to Advanced SubStation Alpha .ass for editing in tools like Aegisub. The .sub extension covers both MicroDVD and SubViewer, and this tool detects which you have. MicroDVD stores frame numbers, so you can set the frame rate to get the timing right. It runs in your browser; nothing is uploaded.
This is a frame-based MicroDVD file, so its timing depends on the video's frame rate. If the file declares its own rate that is used; otherwise pick the rate that matches your video.
SUB in, editable ASS out
The .sub extension is shared by MicroDVD (frame-based, markers like {25}{50}) and SubViewer (time-based). This tool reads whichever it is, converting MicroDVD frames to real time using the frame rate you set.
The output is a minimal, valid ASS script with a clean default style, each line written as a dialogue event with its timing and text. Open it in a subtitle editor to restyle, reposition, or tweak. Set the frame rate for MicroDVD files so the timing matches your video; SubViewer files need no rate.
FAQ
How does it tell the two SUB formats apart?
By the content. Curly-brace frame markers like {25}{50} mean MicroDVD; a header with HH:MM:SS timing lines means SubViewer. It picks the right reader automatically.
What styling does the ASS file get?
A single clean default style you can change in an editor. The SUB formats don't carry the rich styling ASS supports, so the tool gives you a neutral, editable starting point.
Is my file uploaded?
No. Everything runs in your browser. Your file never leaves your device and no server is involved.