CaptionStack
Private by design

TTML CONVERTER

TTML files.
Any format.

Convert .ttml captions to SRT, VTT, TTML, and more — or convert anything to .ttml. Free, private, and in your browser.

SRTVTTSBVLRCTTMLJSONCSVTXT
1

Choose your caption file

We’ll detect the format automatically. Drop several files to convert them all at once.

Don’t have a file handy?
2

Choose an output format

Select what you need on the other side.

100% privateYour files never leave this device.
8 formatsBuilt for the caption formats you use.
No limitsConvert as often as you need.

About TTML (.ttml) files

Timed Text Markup Language is a W3C XML format for captions and subtitles. It underpins broadcast standards such as EBU-TT and IMSC and is required by many streaming platforms and accessibility regulations. Each <p> element carries begin and end (or dur) attributes and the caption text.

Where .ttml is used

  • Netflix, Amazon, and other streaming deliveries (IMSC/TTML)
  • Broadcast workflows (EBU-TT, SMPTE-TT)
  • Media asset management systems

What a .ttml file looks like

<tt xmlns="http://www.w3.org/ns/ttml">
  <body><div>
    <p begin="00:00:01.000" end="00:00:04.200">Caption files, meet your new converter.</p>
  </div></body>
</tt>

What converts and what doesn’t

Text, timing, and xml:id identifiers are converted. Styles, regions, and layout metadata are not preserved, and inline <span> formatting is flattened to plain text with <br/> becoming line breaks.

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All caption formats