Convert TTML to DFXP Online Free

Drag & drop your .ttml file here, or click to browse

Converts to DFXP on secure servers · first daily conversion free · no signup

Your first conversion each day is free. A $2.99 one-time Day Pass unlocks 24 hours and ends by itself.

Convert W3C TTML subtitle files to DFXP format for compatibility with legacy broadcast delivery systems and professional subtitle tools. ChangeThisFile handles the conversion server-side.

By ChangeThisFile Team · Last updated: March 2026

Quick Answer

ChangeThisFile converts TTML to DFXP on a secure server. Upload your TTML subtitle file and it is re-encoded as DFXP for legacy broadcast systems and professional subtitle tools. Files are auto-deleted after conversion. Free with no signup required.

First daily conversion free No signup required Encrypted transfer · Async jobs kept up to 24h Queued when needed Updated May 2026

TTML vs DFXP: Format Comparison

Key differences between the two formats

Feature	TTML	DFXP
Standard body	W3C Timed Text Working Group	Industry EBU/SMPTE distribution profile
Version support	TTML 1.0, TTML 2.0	TTML 1.0 subset
Namespace	W3C ttml namespace	Older TTAF exchange namespace (varies)
Modern tool support	High — current broadcast systems	Moderate — legacy systems
Feature set	Full W3C spec including TTML 2	Distribution-focused subset
Validation	W3C TTML validator	DFXP/TTAF schema
Best for	Current streaming delivery	Legacy broadcast tool compatibility

When to Convert

Common scenarios where this conversion is useful

Submitting to legacy broadcast systems requiring DFXP

Some older broadcast delivery systems and subtitle management tools still require DFXP with legacy namespace declarations. Converting modern TTML output to DFXP ensures compatibility with these systems.

Round-tripping between subtitle vendors

One subtitle vendor may deliver TTML while another tool in the workflow requires DFXP. This converter normalizes the format for interoperability between tools in a mixed professional environment.

Archiving current TTML in a legacy-compatible format

Organizations maintaining long-term subtitle archives may need DFXP copies for compatibility with older retrieval and playback systems alongside modern TTML masters.

Who Uses This Conversion

Tailored guidance for different workflows

Video Editors & Subtitlers

Convert TTML caption files to DFXP for the subtitle track your editor or delivery spec requires
Move TTML subtitles into DFXP to hand off to an editor working in a different tool

After converting to DFXP, confirm the cue timings still line up with the video

Check that line breaks and special characters survived the TTML to DFXP conversion

Content Creators & YouTubers

Convert TTML captions to DFXP to upload alongside your video on YouTube, Vimeo, or social platforms
Turn a TTML caption file into DFXP to make your video clearer and more accessible

Keep individual DFXP cues short (about one to two lines) so captions stay readable on screen

Preview the DFXP captions on the actual video to catch any timing drift before publishing

Accessibility & Localization Teams

Convert TTML subtitles to DFXP to meet the caption format an accessibility or compliance spec requires
Prepare TTML captions as DFXP to hand to translators or a localization workflow

Speaker labels and on-screen positioning only carry over if DFXP supports them, so spot-check the result

Validate the DFXP file in a caption checker to catch overlapping cues or malformed timestamps

How to Convert TTML to DFXP

1

Upload your TTML file

Drag and drop your TTML subtitle file onto the converter, or click browse to select it. The file is transferred over an encrypted connection.
2

Server-side conversion

The server parses the TTML XML, extracts cue timing and text, and re-encodes as DFXP with appropriate namespace declarations for professional delivery system compatibility.
3

Download the DFXP

Save your converted DFXP file. The server copy is automatically deleted after processing.

Automate this conversion

Convert TTML to DFXP via API

Integrate this conversion into your pipeline with 3 lines of code. Free tier: 25 conversions/month.

curl -X POST https://changethisfile.com/v1/convert \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@input.ttml" \
  -F "target=dfxp" \
  -o output.dfxp --fail

const form = new FormData();
form.append('file', fileInput.files[0]);
form.append('target', 'dfxp');

const res = await fetch('https://changethisfile.com/v1/convert', {
  method: 'POST',
  headers: { 'Authorization': 'Bearer YOUR_API_KEY' },
  body: form
});
const blob = await res.blob(); // your converted DFXP file

Replace YOUR_API_KEY with your free key — no credit card needed.

Get a free API key

Frequently Asked Questions

What is the difference between TTML and DFXP?

TTML is the W3C core specification; DFXP is an older distribution profile of TTML defined by the SMPTE/EBU for broadcast interchange. Both are XML formats; DFXP uses an older namespace convention and is limited to TTML 1.0 features.

Is this conversion lossless?

Timing and text content are fully preserved. TTML 2.0-specific features not supported in DFXP are dropped. The conversion is a namespace and schema normalization.

Which tools require DFXP instead of TTML?

Some legacy EZTitles, Cavena, and Fab Subtitler versions, as well as certain broadcast content management systems, require DFXP with older namespace declarations rather than modern W3C TTML.

Are my files deleted after conversion?

Yes. Files are transferred over HTTPS and automatically deleted from the server after the DFXP is ready for download.

Does the output use the TTAF exchange namespace?

The output DFXP uses standard W3C TTML namespace with DFXP-compatible structure. If your legacy tool requires the older TTAF namespace specifically, you may need to manually update the namespace declarations.

Is there a file size limit?

TTML files are XML text and typically compact. The 50 MB server limit is not a concern for subtitle files.

Can I convert DFXP back to TTML?

Yes. ChangeThisFile supports DFXP to TTML conversion for round-tripping between formats.

What timestamp format does DFXP use?

DFXP uses HH:MM:SS.mmm for begin and end attributes on each p element, same as TTML.

Does this work for IMSC-1 TTML?

IMSC-1 is a Netflix-specific TTML profile. The converter extracts cues from any valid TTML XML. IMSC-1 specific metadata in the tt element head is preserved in the DFXP output where compatible.

Can I validate the DFXP output?

Yes. The output is well-formed XML that passes any XML parser. For DFXP-specific validation, use the W3C TTML validator or a DFXP schema validator.

Related Conversions

Compare TTML vs DFXP

Popular Tools

Free tools to edit, optimize, and manage your files.

PDF Merge PDF Compress Image Compress Video Compress PDF Split Video to GIF Data Prettify

Read our guides on file formats and conversion

Ready to convert your file?

Convert TTML to DFXP instantly — free, no signup required.

Start Converting