Novus Convert
Convert files
Document format

TTML converter

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.

Private for supported formats — processed in your browser

Convert supported files

Runs on your device

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.

Where TTML comes from

The W3C published Timed Text Markup Language 1.0 in 2010, drawing on earlier work in SMIL and the broadcast caption formats it was meant to replace. TTML2 followed in 2018, and a family of profiles grew around it — DFXP for distribution, SMPTE-TT and EBU-TT for broadcast, IMSC for streaming — all sharing the same core document shape.

How TTML works

  • The root <tt> element declares the TTML namespace and optional ttp: parameters such as frameRate, tickRate, and timeBase.
  • Time expressions come in five shapes: clock time, clock time with a frame field, offsets in s/ms/h/m, frame offsets, and tick offsets.
  • Styling lives in <styling> and <layout> sections referenced by cues, which separates presentation from timing.
  • Because it is XML, a TTML document can declare external entities — a parser that resolves them is an information-disclosure risk.

When to use TTML

  • Delivering captions to broadcast and streaming platforms that mandate a TTML profile
  • Interchanging subtitles between systems that disagree on everything except XML
  • Archiving captions in a specified, validatable format
  • Converting broadcast captions down to WebVTT for the open web

Strengths and limitations

Strengths

  • A real published standard with formal profiles rather than a de facto convention
  • Expresses styling, layout, and regions that plain caption formats cannot
  • Validatable with ordinary XML tooling

Limitations

  • Far more verbose than SubRip or WebVTT for the same cues
  • Profile differences mean a valid TTML file can still be rejected by a specific platform
  • No browser plays it directly; the web path is WebVTT

Compatibility

Broadcast and streaming toolchains — including the DFXP, SMPTE-TT, EBU-TT, and IMSC profiles — read and write TTML, and caption editors such as Subtitle Edit export it. Browsers do not. Novus Convert parses TTML locally with document types and external entities refused outright, resolves all five time-expression shapes, and converts to any of the twelve timed-text targets.

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.

Convert TTML to another format

Convert other formats to TTML