How to Make TTML Subtitle Files

Timed Text Markup Language (TTML) powers subtitles and captions across broadcast, OTT, and regulatory workflows that demand structured XML. QuickLRC streamlines TTML creation with an intuitive maker for manual editing and an AI generator for fast turnaround projects. Follow this guide to stay compliant with TTML1/IMSC profiles while working efficiently.

Understand the TTML Essentials

TTML is XML-based, so every document relies on namespaces, structural elements, and precise timing attributes. Keep these building blocks in mind:

<tt> root defines namespaces, frame rate, and document metadata.
<head> holds layout, style, and metadata definitions.
<body> / <div> / <p> organize caption regions and timed paragraphs.
Timing attributes like begin, end, or dur use HH:MM:SS.mmm or frame offsets.
Styles can reference regions, fonts, colors, and alignment through XML attributes.

<?xml version="1.0" encoding="UTF-8"?>
<tt xml:lang="en" xmlns="http://www.w3.org/ns/ttml">
  <head>
    <layout>
      <region xml:id="bottom" tts:displayAlign="after" tts:textAlign="center" xmlns:tts="http://www.w3.org/ns/ttml#styling" />
    </layout>
  </head>
  <body region="bottom">
    <div>
      <p begin="00:00:01.200" end="00:00:04.500">Welcome to our video tutorial</p>
      <p begin="00:00:05.000" end="00:00:08.300">TTML keeps subtitles perfectly in sync</p>
      <p begin="00:00:09.100" end="00:00:12.800">Stay consistent with regions and include spacing</p>
    </div>
  </body>
</tt>

Manual Workflow with TTML Maker

Choose the TTML Maker when delivery specs call for precise region placement, accessibility metadata, or conformance with Dolby, Netflix, or broadcast guidelines.

1. Gather Specs and Assets

Collect platform style guides (regions, fonts, safe areas) and regulatory requirements.
Prepare transcripts with speaker changes and accessibility notes (e.g., [MUSIC], [APPLAUSE]).
Identify language codes and localization needs before you begin.

2. Configure Layout and Styles

In /manual-sync, define regions, default styles, and safe margins. Map each transcript segment to the correct region for multi-position deliveries.

3. Time and Tag Paragraphs

Set begin/end times with the playback scrubber, then enrich captions with speaker IDs or description tags using TTML attributes. Maintain 1–2 frame padding between consecutive cues.

QuickLRC writes precise ISO timestamps, reducing XML validation errors downstream.

4. Export and Validate

Export the `.ttml` file and validate against OTT/broadcast schemas. Test playback in reference players like AWS MediaConvert preview or DASH.js.

Open TTML Maker Review the full TTML specification

AI Workflow with TTML Generator

Use the TTML Generator to create compliant XML faster, then tailor styles and metadata to match delivery specs.

Upload media: Go to /auto-sync, select the media file, and choose the correct language.
AI caption draft: QuickLRC generates TTML paragraphs with precise timing and default styling.
Edit text and timing: Fix terminology, adjust timings, and set paragraph IDs without touching raw XML.
Apply styles/regions: Map cues to regions or custom style IDs to comply with platform requirements.
Export and verify: Download the `.ttml`, then validate with the TTML Validator or industry QA tools.

Try the TTML Generator

Manual vs. AI: Pick the Right Workflow

TTML Maker (Manual)

Best for high-stakes deliveries with strict layout, metadata, or accessibility requirements.
Full control over regions, style inheritance, and XML attributes.
Requires careful QA but ensures compliance with IMSC and broadcaster specs.

TTML Generator (AI)

Ideal for rapid drafts, multi-language localization, or when transcripts are unavailable.
Automatically handles timing and paragraph structure—just adjust styling and metadata.
Accelerates production while keeping exports XML-valid.

Quality Checks Before Publishing

Slot these QA steps into your delivery workflow to catch TTML issues early:

XML validation: Ensure the document is well-formed and references required namespaces.
Region safety: Verify captions stay within title-safe areas and follow platform alignment rules.
Timing accuracy: Check for overlaps, excessive dwell times, or missing frame padding.
Accessibility tags: Include speaker identifiers and sound effect descriptions where required.

Ready for Your Next Subtitle Project?

Hands-on Control

Author XML in TTML Maker

Fast Turnarounds

Generate TTML with AI