Free, instant, and entirely in your browser — your subtitle file is never uploaded.
MicroDVD counts frames, not seconds — this has to match the video.
ASS is a typesetting language that happens to carry subtitles. Named styles, exact positioning, rotation, fades, karaoke timing and vector drawing all live in the file, split across a [Script Info], a styles and an [Events] section.
SBV is YouTube's own caption format, and about as simple as SRT with one line less: no sequence number, and the two timestamps separated by a comma rather than an arrow.
An ASS file exists because someone typeset it, and YouTube has no way to show that work. Positioned signs, styled speakers, anything drawn over the picture — none of it crosses, and unlike a desktop player YouTube will not even let you supply a styled file as an alternative. What you are really doing here is extracting the dialogue track from a piece of typesetting so the video can carry captions on a platform that only does captions. Keep the ASS: it is the version with the craft in it.
You want SBV because you are uploading to YouTube and want the format its own editor writes. It is worth knowing this is rarely necessary — YouTube accepts SRT quite happily — so choose SBV when a workflow or a tool specifically asks for it, not as a default.
This is a downgrade in capability, and worth doing on purpose. The source format is a typesetting language: named styles, exact positions, fades, karaoke timing, even vector drawings. The target has none of that — it has text and two timestamps. So the words and the timing come across intact, and everything that decided how they looked on screen is dropped. Signs translated in place, on-screen labels positioned over the original, coloured speaker attribution: all of it becomes ordinary subtitle lines. That is the trade for a file almost every player and platform will accept without argument.
No. The conversion runs in your browser using JavaScript — your ASS file is read from disk, converted in memory and handed back as a download. Nothing is transmitted, so there is nothing for us to store or delete. You can disconnect from the internet after this page loads and the conversion still works.
An ASS file exists because someone typeset it, and YouTube has no way to show that work. Positioned signs, styled speakers, anything drawn over the picture — none of it crosses, and unlike a desktop player YouTube will not even let you supply a styled file as an alternative. What you are really doing here is extracting the dialogue track from a piece of typesetting so the video can carry captions on a platform that only does captions. Keep the ASS: it is the version with the craft in it.
The page checks before it converts. Subtitle formats are identified by what is inside the file rather than by the extension — which matters, because .sub alone is used by three unrelated formats. If you hand this page something that is not ASS, it says so and points you at the all-format converter instead of producing a broken file.