Format guide8 min read

DFXP subtitle format: what it is and how to convert it

DFXP is an older TTML profile used by Netflix and Flash-era video. If you have .dfxp files, here's how to convert them to SRT, VTT, or any modern format.

DFXP XML file structure shown in a code editor.
The short version

DFXP (Distribution Format Exchange Profile) is a TTML 1.0 profile from the Flash era. It's still found in broadcast archives and legacy Netflix deliverables. Here's how to work with it in 2026.

DFXP stands for Distribution Format Exchange Profile. It's a profile of TTML 1.0 — meaning a .dfxp file is just XML with the same structure as TTML. The format was used by Adobe Flash captions and Netflix's pre-IMSC ingest pipeline. In 2026, you'll encounter DFXP files when working with broadcast archives, legacy DAM systems, or older streaming deliverables.

What is a DFXP file?

A .dfxp file is XML — open it in a text editor and you'll see <tt>, <body>, <div>, and <p> elements with timing attributes. It's functionally identical to TTML. The .dfxp extension is just a naming convention from the Flash era; most TTML parsers read it without modification.

  • Extension: .dfxp (sometimes .xml)
  • Base format: TTML 1.0 (XML)
  • Origin: Adobe Flash captions, Netflix pre-2017 ingest
  • Styling: full TTML styling support (regions, styles, positioning)
  • Timing: HH:MM:SS.mmm or HH:MM:SS:FF

How to convert DFXP to SRT

Use SoCaptions' free DFXP to SRT converter. Paste the .dfxp XML contents, get a clean .srt file back. Styling and positioning are stripped (SRT doesn't support them), but timing and text are preserved exactly.

  1. 01Open the .dfxp file in any text editor.
  2. 02Copy the full XML contents.
  3. 03Paste into SoCaptions' DFXP to SRT converter.
  4. 04Download the .srt — ready for any video editor or platform.

DFXP vs TTML vs IMSC

All three are related. TTML is the W3C standard. DFXP is an older profile of TTML 1.0. IMSC is the modern streaming profile (TTML 1.1+) used by Netflix, Apple TV+, and Disney+ today. If you're delivering to a modern streaming platform, they want IMSC, not DFXP. If you're converting legacy files for editing, convert DFXP to SRT.

Why DFXP still exists

Broadcast and streaming archives ingested before IMSC took over (roughly pre-2017) store captions as DFXP. Re-encoding entire libraries is expensive, so the format persists in archives. You'll also find DFXP in legacy corporate video platforms, older LMS systems, and some government video archives.

When to convert away from DFXP

  • Editing in Premiere, DaVinci, CapCut, or any consumer editor — convert to SRT.
  • Embedding on a website with HTML5 <video> — convert to VTT.
  • Delivering to modern streaming (Netflix, Apple TV+) — convert to IMSC.
  • Archiving for long-term storage — keep the DFXP as-is; it's valid XML and future-proof.
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