Add your TTML file
Drop one or more .ttml files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Converting a .ttml file to .ssa extracts the document's content from its office package into a portable form. Free, private, and validated — the file never leaves your browser.
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.Converting a .ttml file to .ssa extracts the document's content from its office package into a portable form. A .ttml file is a Timed Text Markup Language document: an XML vocabulary in which each <p> element carries begin and end (or dur) attributes plus the caption text. It is the W3C standard that broadcast and streaming systems use as their interchange format for captions and subtitles.
An .ssa file is a SubStation Alpha subtitle script — the v4.00 predecessor of Advanced SubStation Alpha. It uses the same [Script Info] / styles / [Events] layout and the same Dialogue timing, with a smaller style table and no v4+ extensions. For this route the practical draw is still rendered by every libass-based player decades later and simpler than the v4+ revision, so easier to parse and hand-edit — balanced against superseded by .ass, which every current authoring tool writes instead, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .ttml, far more verbose than SubRip or WebVTT for the same cues. Switching to .ssa buys you still rendered by every libass-based player decades later, which is why it is the better fit for reading subtitle scripts from late-1990s and early-2000s releases. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | Timed Text Markup Language (.ttml) | SubStation Alpha subtitles (.ssa) |
|---|---|---|
| Format type | Text-based — characters and structure, so there is no visual quality loss | Text-based — characters and structure, so there is no visual quality loss |
| How it stores data | the root <tt> element declares the TTML namespace and optional ttp: parameters such as frameRate, tickRate, and timeBase | the [V4 Styles] section uses TertiaryColour and AlphaLevel fields that the later [V4+ Styles] table replaced |
| Strongest at | delivering captions to broadcast and streaming platforms that mandate a TTML profile | reading subtitle scripts from late-1990s and early-2000s releases |
| Weak spot | far more verbose than SubRip or WebVTT for the same cues | superseded by .ass, which every current authoring tool writes instead |
| Metadata | styling, layout, and region definitions are read past rather than applied: timing and text convert, presentation does not, and no external resource is ever fetched | the v4 style table and script headers describe presentation only; timing and text survive conversion, styling does not |
Drop one or more .ttml files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Select .ssa in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if SSA is selectable, the route is real and validated.
Press Convert. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded.
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid SSA file. Outputs keep the original filename with the .ssa extension.
There is no visual quality to lose — ttml is text-oriented and ssa is text-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Yes — the .ttml file is processed inside your browser tab and never uploaded. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded. Close the tab and the file is gone from memory.
VLC, mpv, and other libass-based players handle .ssa alongside .ass, and Aegisub opens it for editing. No browser renders it. Novus Convert parses the v4 events locally through the same cue model as .ass and exports to any of the twelve timed-text targets.
It depends on the content: the [V4 Styles] section uses TertiaryColour and AlphaLevel fields that the later [V4+ Styles] table replaced. Convert one representative file first and compare before batch-processing a large set.
In .ttml, styling, layout, and region definitions are read past rather than applied: timing and text convert, presentation does not, and no external resource is ever fetched. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .ttml → .ssa → .ttml is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.