From a flat list to a styled document
SRT is just numbered cues. ASS is a document with a header, a style table and an events list. This tool builds that
structure for you: a minimal [Script Info], one [V4+ Styles] entry called
Default, and an [Events] section containing your lines as Dialogue: events.
input.srt
1
00:00:04,180 --> 00:00:07,920
<i>Who's there?</i>
output.ass — [Events]
Dialogue: 0,0:00:04.18,0:00:07.92,Default,,0,0,0,,{\i1}Who's there?{\i0}Millisecond timing is written in ASS centiseconds, the cue text moves into the last field, and inline tags become ASS overrides. The result opens cleanly in Aegisub, VLC, MPV and any ASS-aware player.
When you need ASS
Convert to ASS when you’re about to do something SRT can’t express: reposition a caption to avoid covering on-screen text, colour a second speaker, set a specific font for a release, typeset a sign, or build karaoke. ASS is also the working format for Aegisub, so this is the usual on-ramp from a plain transcript to a styled subtitle.
What’s preserved
- Timing — converted to centiseconds (ASS’s native resolution); ordering kept.
- Text and line breaks — preserved; newlines become ASS
\\N. - Inline formatting —
<i>/<b>/<u>become override toggles; other tags are dropped with a notice. - A sane default style — readable white-on-outline that you can restyle later.
- Encoding — non-UTF-8 input is detected and decoded before conversion.
Limits
None meaningful. The tool can’t invent styling you didn’t have — it gives you a clean, valid ASS file to build on. Everything runs locally, instantly, with no upload.