Convert SRT to ASS/SSA
Turn a plain SRT into a valid Advanced SubStation Alpha file you can style in Aegisub. Runs in your browser — nothing is uploaded.
This is the conversion that goes uphill. SRT holds dialogue and timing and nothing else; ASS holds fonts, colours, positioning, karaoke and effects. Going from ASS down to SRT means discarding things, and every converter can do it. Going the other way means the styling has to come from somewhere, and the honest answer is that it cannot come from the source file, because the source file never had any. Subtitle Doctor writes a correct, minimal ASS file instead: proper [Script Info], one Default style sized for 1080p, and every line of your dialogue as a Dialogue event with the timing converted from milliseconds to ASS centiseconds. It opens cleanly in Aegisub, VLC and mpv, and it is the right starting point for styling work — because you are going to restyle it anyway.
Worth knowing
- Nothing about your dialogue is invented, but the style is: you get one Default style (Arial 54, white with an outline, bottom-centre, PlayRes 1920x1080) because a valid ASS file cannot exist without at least one style defined.
- Italic, bold and underline tags survive the trip: <i>text</i> becomes {\i1}text{\i0}, which is the same effect written in the other format’s syntax rather than new styling.
- Literal curly braces in your dialogue are removed, because braces delimit override blocks in ASS — a stray "{" would silently swallow the rest of the line in every player.
- A hard line break inside a cue becomes \N, the ASS hard-break marker, rather than a real newline, which would end the Dialogue event early and corrupt the file.
- Commas in dialogue are safe. Text is the final field on a Dialogue line, so everything after the last structural comma is treated as text no matter how many commas it contains.
- If you feed an ASS file back in, Subtitle Doctor returns your original bytes untouched rather than regenerating it — regeneration would throw away exactly the styling you came here to keep.
FAQ
Will this give my subtitles the styling of a fansub release?
No, and no tool can. Fansub styling is authored by hand in Aegisub — fonts, colours, positions and effects chosen shot by shot. An SRT contains none of that information, so there is nothing for a converter to recover. What you get is a clean, valid file with one readable default style, ready for you to restyle.
Why would I convert to ASS at all?
Because ASS is the working format for subtitle styling. If you want to reposition a line that covers on-screen text, set a font, colour a speaker, or add karaoke timing, you need a format that can express those things. Converting first gives you a file Aegisub can open and edit properly.
What is the difference between .ass and .ssa?
SSA is the older v4 format and ASS is v4+, which added the styling capabilities most players and editors now assume. Subtitle Doctor writes v4+ with the ScriptType marker set accordingly. Tools that read SSA will generally read ASS as well, so ASS is the safer choice unless something specifically demands the older format.