Free online DFXP to VTT converter

HTML5 video players and platforms that use the <track> element commonly require WebVTT caption files rather than DFXP or TTML. Conversion rewrites XML timed-text cues into a .vtt file that can be uploaded, edited, and tested in browser-based playback.

DFXP and TTML

DFXP (Distribution Format Exchange Profile) is a legacy timed-text format name associated with TTML (Timed Text Markup Language). In practice, files labeled .dfxp, .ttml, or sometimes .xml may contain TTML-based captions, but a generic XML file is not necessarily a subtitle file.

DFXP/TTML stores timed text in XML elements, commonly with cues such as <p begin="00:00:12.000" end="00:00:15.000">. Broadcasters, streaming workflows, caption vendors, and subtitle-authoring systems use TTML-based formats because they can define timing, language metadata, regions, styling, and text spans.

WebVTT format

WebVTT is a plain-text caption format saved as .vtt. A valid file starts with WEBVTT, followed by cues containing a timing line and text:

WEBVTT

00:00:12.000 --> 00:00:15.000
Caption text

WebVTT is the format supported by browser video tracks, for example <track kind="subtitles" src="captions.vtt" srclang="en">. Its text structure is easier to inspect and edit than XML, and it supports basic cue settings, limited inline markup, and CSS styling through browser-specific WebVTT support.

Convert the file

Upload the DFXP or TTML caption file to the converter on 101convert.com, select VTT as the output format, start the conversion, and download the resulting .vtt file. No software installation is required.

For local conversion and manual correction, Subtitle Edit can open many TTML/DFXP files and save WebVTT output. Use File → Open to load the source, review the cue list and timing, then choose File → Save as and select WebVTT (*.vtt).

Do not change only the filename extension. Renaming captions.dfxp to captions.vtt leaves the XML content unchanged; a converter must parse the timed-text document and write WebVTT cue syntax.

Check the converted captions

Open the output in a text editor and verify that the first line is WEBVTT and that cue timestamps use a period before milliseconds, such as 00:01:02.500. Test the file in the exact target player or upload system.

Text and cue timing usually convert directly, but DFXP/TTML features do not have a complete WebVTT equivalent. Regions, pixel-based positioning, fonts, colors, background images, transforms, complex nested spans, and profile-specific metadata can be simplified or discarded. WebVTT cue placement and browser CSS cannot reliably reproduce every TTML layout.

Inspect line breaks, overlapping cues, speaker labels, right-to-left text, and captions near the start and end of the video. Files using frame-based timing, tick rates, or a declared frame rate require correct interpretation by the converter; compare several cues against the video to detect offset or timing drift. Image-based subtitles and non-text TTML extensions may require separate handling rather than a text-only conversion.