Convert SUB to SSA Online

SUB vs SSA: Which One Should Your Subtitles Live In?

MicroDVD .sub and SubStation Alpha .ssa are both styling-capable subtitle formats, which makes this conversion look like a straight upgrade. It mostly is — SSA has a real style system, named styles, margins and a proper header — but the two express styling in completely different ways, and this converter does not translate between them. The short version: convert to SSA when you want a file that Aegisub, VLC and libass-based players will render and that you intend to style yourself; stay with a simpler target if all you need is the dialogue on screen.

Side-by-side Comparison

Property	MicroDVD (.sub)	SubStation Alpha (.ssa)
Origin	De facto format from the MicroDVD player era	SubStation Alpha, the fansubbing authoring tool
File shape	One cue per line, no header	Sectioned INI-style file: [Script Info], [V4 Styles], [Events]
Timing base	Frame numbers	Clock time, h:mm:ss.cc
Timing precision	One frame — 40 ms at 25 fps	Centiseconds, so 10 ms
Frame rate needed to read it	Yes	No
Styling model	Inline codes per cue: {y:i}, {y:b}, {c:$BBGGRR}	Named styles defined once in a header and referenced by every line
Colour notation	$BBGGRR — blue, green, red	&HAABBGGRR hex, with an alpha byte
Line break within a cue	| pipe	\N
Positioning	{P:x,y}	Alignment plus per-line margins, and override tags in the ASS variant
Renderers	Legacy DivX-era players	libass (VLC, mpv, FFmpeg), VSFilter, Aegisub
Modern successor	None — it is the end of that line	ASS, the Advanced SubStation Alpha v4+ variant

When SSA Is the Right Target

• You are opening the file in Aegisub or another subtitle editor to do real typesetting work, and you want a format with a style table waiting for you.
• You need the subtitles rendered by libass — the engine behind VLC, mpv and FFmpeg's subtitle burn-in — which reads [V4 Styles] sections as SSA and [V4+ Styles] as ASS.
• You intend to burn the subtitles into the video, where a format with explicit fonts, sizes and margins gives you predictable output instead of leaving it to a player's defaults.
• You want named styles so a single edit changes every line of dialogue at once.

When to Pick a Different Target

• You just want the subtitles to play everywhere with no fuss: SubRip is the universal choice, and SUB to SRT gets you there.
• You are attaching subtitles to an HTML5 <video> element: browsers load WebVTT through <track> and will not read SSA at all.
• You are heading for serious typesetting: ASS, the v4+ evolution of this format, adds override tags, rotation, karaoke and a richer style row. SUB to ASS targets that variant instead.
• You only want the words: SUB to TXT drops timing entirely and gives you a readable transcript.

What the SSA Output Actually Contains

Section	What this converter writes
[Script Info]	ScriptType: v4.00 and Collisions: Normal — this is SSA V4, not ASS V4+
[V4 Styles]	The standard V4 Format: row, plus a single style named DefaultVCD in Arial at size 28
Style colours	Written in the &HAABBGGRR hex notation that libass expects, rather than raw decimals
[Events]	The V4 Format: row — Marked, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue lines	One per cue, Marked=0, times as h:mm:ss.cc, all referencing the DefaultVCD style
Line breaks	A two-line cue is written with \N between the lines
Source styling	Not carried across — MicroDVD's inline codes are stripped, not converted

That last row is the honest cost of this conversion. You get a well-formed SSA file with one usable default style; any italics, colours or fonts the MicroDVD author specified are gone, and you reapply them in an editor.

How to Convert SUB to SSA

1. Load Your .sub File: Click *� Upload .sub or paste MicroDVD text into the Input (SUB) box — the counter above it confirms the content arrived. One file per conversion.
2. Check the Format Dropdowns: From format is preset to SUB and To format to SSA. Both dropdowns list all 13 supported subtitle formats, so ASS is one click away if you want the newer variant.
3. Click Convert: Press Convert →. The full SSA document appears in the output panel; the first run shows "Loading subsrt…" for a moment while the parser loads.
4. Copy or Download the SSA: Use *� Copy or ⬇ Download .ssa. The conversion runs in your browser.

The Frame Rate Problem You Inherit From MicroDVD

SSA records real times, so once you are in it the frame rate stops mattering. Getting there is the hard part: MicroDVD's {1440}{1560} values are frame indices, and turning them into 0:01:00.00 requires knowing the video's frame rate, which the file does not reliably carry. The convention is a first line reading {1}{1}23.976; FFmpeg's MicroDVD reader scans the first three lines for it and defaults to 23.976 fps otherwise.

This converter assumes 25 fps, has no frame-rate control, and does not interpret that first line — it parses as an ordinary cue and becomes a Dialogue line whose text is 23.976. Delete it from the input, or delete that Dialogue line from the output.

Preview the SSA against your video before you use it. MicroDVD timing scale is a defect we currently have open, so treat the Dialogue timecodes as something to verify; the dialogue text, cue order and \N line breaks convert reliably.

Frequently Asked Questions

Is SSA the same thing as ASS?

They are two generations of one format. SSA is SubStation Alpha V4; ASS is Advanced SubStation Alpha V4+, which adds override tags, rotation and karaoke timing. libass tells them apart by the styles section header — [V4 Styles] is treated as SSA, [V4+ Styles] as ASS. This page produces the V4 flavour, declared as ScriptType: v4.00. If you want the newer one, switch the To format dropdown to ASS.

Will my MicroDVD italics and colours become SSA styles?

No. The {y:i}, {y:b}, {y:u}, {f:name}, {s:n} and {c:$BBGGRR} codes are removed together with their braces when the file is parsed, and are not rewritten as SSA style attributes or override tags. Every converted line ends up on the single default style, and you restyle in Aegisub. The two colour notations do not line up either — MicroDVD writes $BBGGRR while SSA uses &HAABBGGRR with an alpha byte.

How precise are SSA timings compared to MicroDVD?

SSA Dialogue lines carry two decimal places — centiseconds, or 10 ms. MicroDVD's resolution is one frame, which at 25 fps is 40 ms and at 23.976 fps about 41.7 ms. So the target is finer-grained than the source, and no precision is lost in that direction; the risk in this conversion is the frame-rate assumption, not rounding.

What style does the converted file use?

A single style named DefaultVCD, set in Arial at size 28 with standard margins, and every Dialogue line references it. We checked the emitted header specifically for one thing: the style colours are written as &HAABBGGRR hex, which is the notation libass parses, rather than the raw decimal values that some SSA writers produce and that renderers reject.

Will VLC play the file this produces?

VLC renders subtitles through libass, which reads both [V4 Styles] SSA and [V4+ Styles] ASS files, so yes. As always, check the timing against the video first — and if the subtitles do not appear at all, confirm VLC is loading the track, since it matches external subtitle files by filename against the video.

Does the pipe in a MicroDVD cue become a line break?

Yes. | is MicroDVD's line separator, and it survives as a real line break, written in SSA's own notation as \N. So {100}{200}Line one|Line two becomes a Dialogue line containing Line one\NLine two, which renders as two lines.

Does my file get uploaded when I convert?

No. This is a client-side page: your browser reads the .sub locally, converts it with JavaScript running on the page, and builds the download in memory. The converter code is fetched from us once; your subtitle file never is.

The converter says no cues were parsed — what does that mean?

That nothing in the input matched {digits}{digits}text. .sub is an overloaded extension: SubViewer files use timestamps instead of frames, and a .sub with an .idx beside it is VobSub, which holds bitmap images of subtitles rather than text and needs OCR before any converter can help. Open the file in a text editor — MicroDVD is readable and full of curly braces.

Can I convert SSA back to MicroDVD later?

You can, but treat it as a one-way trip in practice. Any styling you add in Aegisub has no MicroDVD equivalent beyond the handful of inline codes, and writing frame numbers again means committing to a frame rate assumption a second time. If you need a durable archive copy, keep the SSA.