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.
TTML to ASS
Converting a .ttml file to .ass extracts the document's content from its office package into a portable form. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop TTML files here
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.About converting Timed Text Markup Language to Advanced SubStation Alpha subtitles
Converting a .ttml file to .ass 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 .ass file is an Advanced SubStation Alpha subtitle script: an INI-like document whose [Events] section holds Dialogue lines with start and end times, a named style, and text that may carry inline override tags. It is the format fansub and anime communities standardised on because it can position, colour, and animate captions rather than only time them. For this route the practical draw is the most expressive plain-text subtitle format in common use and precise positioning and per-style typography that SubRip cannot express — balanced against styling and positioning are lost the moment the file is converted to SubRip, WebVTT, or a lyric format, which is worth knowing before you commit a large batch.
Why convert TTML to ASS?
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 .ass buys you the most expressive plain-text subtitle format in common use, which is why it is the better fit for styled and positioned captions muxed into Matroska releases. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
TTML vs ASS at a glance
| Aspect | Timed Text Markup Language (.ttml) | Advanced SubStation Alpha subtitles (.ass) |
|---|---|---|
| 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 script is divided into [Script Info], [V4+ Styles], and [Events] sections, each with its own Format line naming the fields that follow |
| Strongest at | delivering captions to broadcast and streaming platforms that mandate a TTML profile | styled and positioned captions muxed into Matroska releases |
| Weak spot | far more verbose than SubRip or WebVTT for the same cues | styling and positioning are lost the moment the file is converted to SubRip, WebVTT, or a lyric format |
| 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 | script metadata and the style table describe presentation rather than the cues themselves; conversion keeps timing and text and reports styling as lost, because no caption target can carry it |
Pick ASS as the output
Select .ass in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if ASS is selectable, the route is real and validated.
Convert on your device
Press Convert. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid ASS file. Outputs keep the original filename with the .ass extension.
TTML to ASS questions, answered
Will converting TTML to ASS lose quality?
There is no visual quality to lose — ttml is text-oriented and ass 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.
Is it private to convert TTML files here?
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.
Where will the ASS file work?
VLC, mpv, MPC-HC, and anything else built on libass render .ass faithfully, and Aegisub remains the standard authoring tool. Browsers and most streaming platforms do not accept it, which is why converting to WebVTT or SubRip is the usual delivery step. Novus Convert reads the [Events] dialogue cues locally, strips override tags to plain text, and writes any of the twelve timed-text targets.
Will the ASS file be bigger or smaller than my TTML?
It depends on the content: the script is divided into [Script Info], [V4+ Styles], and [Events] sections, each with its own Format line naming the fields that follow. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my TTML file?
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.
Can I convert ASS back to TTML?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .ttml → .ass → .ttml is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.