Does the output include styling or layout metadata?

No. The generated TTML contains the XML declaration, default namespace, xml:lang="en", body, div, and timed elements. It does not include head, styling, region, IMSC, ITV, or EBU-TT-D metadata.

How are multiline cues handled?

Physical cue line breaks become elements inside each TTML element.

Does the converter escape XML special characters?

Ampersands and angle brackets are escaped in text nodes so the generated document can be parsed as XML.

How does this differ from SRT to TTML conversion?

Both converters produce the same basic TTML structure. The VTT parser accepts WebVTT timing and ignores VTT-specific identifiers and settings, while the SRT parser works from numbered SRT blocks.

Can I edit the TTML file after conversion?

Yes. TTML is XML and can be edited in a text or XML editor. Validate the edited document before using it in a delivery workflow.

Is the VTT to TTML converter free?

Yes. It is free, requires no sign-up, adds no watermark, and accepts subtitle files up to 50 MB. Conversion runs locally in your browser.

Processing stays in your browser and the file is not uploaded to AllSubConverter. Browser storage, extensions, and enterprise device policies are controlled separately.

What language metadata is included?

The generated root element uses xml:lang="en". The converter does not detect source language or generate additional language metadata.

Can I batch convert multiple VTT files to TTML?

Yes. Drop several valid VTT files on this page and they open in the workspace Batch tool with TTML preselected. The batch supports up to 200 files.

VTT to TTML Subtitle Converter

Turn timestamped WebVTT cues into a basic TTML XML document.

Drag & drop your VTT file here

or click to browse

Supports .vtt files up to 50 MB

Core Engine Architecture

About VTT to TTML

This browser-based converter reads timestamped WebVTT cue blocks and writes a basic UTF-8 TTML document. Cue start and end times become second-based begin and end attributes, physical line breaks become elements, and XML special characters are escaped. VTT cue identifiers, settings, regions, comments, and styling are not mapped to TTML presentation metadata.

Payload & Syntax Inspector

VTT to TTML Code Syntax & Structure Inspection

Side-by-side code inspection illustrating header definitions, timestamp syntax, and cue payload formatting

Millisecond Sync

input.vtt

VTT SOURCE

WEBVTT
 
00:00:01.000 --> 00:00:04.000
Hello, world!
 
00:00:04.500 --> 00:00:08.000
This is a subtitle file.
 
00:00:08.500 --> 00:00:12.000
Converted locally!

output.ttml

TTML RESULT

<?xml version="1.0" encoding="UTF-8"?>
<tt xml:lang="en" xmlns="http://www.w3.org/ns/ttml">
  <body>
    <div>
      <p begin="1.000s" end="4.000s">Hello, world!</p>
      <p begin="4.500s" end="8.000s">This is a subtitle file.</p>
      <p begin="8.500s" end="12.000s">Converted locally!</p>
    </div>
  </body>
</tt>

Specification Sheet

VTT vs TTML Technical Specifications

Standard Compliant

Input Format

VTT

VTT (WebVTT) is a text subtitle format for web video. A VTT file starts with a WEBVTT header and uses HH:MM:SS.mmm --> HH:MM:SS.mmm cue timing. It can also contain cue identifiers, cue settings, inline tags, NOTE blocks, regions, and style metadata.

Output Format

TTML

TTML (Timed Text Markup Language) is a W3C XML subtitle format. This converter generates a basic UTF-8 document with a default TTML namespace, xml:lang="en", body and div elements, and one element per cue with second-based begin and end attributes.

Format Differences

VTT starts with a WEBVTT header; this TTML output starts with an XML declaration and <tt> root.

VTT uses HH:MM:SS.mmm cue timing; this output uses second-based begin and end attributes.

VTT cue settings and regions are discarded rather than mapped to TTML layout metadata.

VTT inline tags are escaped as literal text rather than becoming TTML spans.

VTT comments and identifiers are not carried over.

The output contains a basic TTML body without styling or profile metadata.

Conversion Troubleshooting & Gotchas

Practical solutions for player compatibility, character encoding, and timing synchronization

4 Common Gotchas

GOTCHA #1

Subtitle timing drifts or appears out of sync on media players

Video files frequently differ in framerate (e.g., 23.976 fps vs 25 fps). If the timing drifts steadily, use our Subtitle Sync tool to adjust the global offset or framerate stretch.

GOTCHA #2

Characters appear as garbled symbols or question marks (Mojibake)

Legacy files saved in Windows-1252, Shift-JIS, or GBK may render incorrectly. Our exporter standardizes output to clean UTF-8. Use our Subtitle Encoding Converter if the source file is corrupted.

GOTCHA #3

Overlapping captions when multiple speakers talk simultaneously

Different formats handle overlapping dialogue differently. If your target player cannot render stacked cues cleanly, open the file in our Subtitle Editor to adjust individual cue timings.

GOTCHA #4

Video editing software (Premiere, DaVinci, Final Cut) rejects the file

Professional NLE software enforces strict syntax rules. Our converter eliminates malformed line breaks and non-standard tags, producing clean, standardized files.

Features

Reads timestamped WebVTT cue blocks directly in your browser

Writes a basic UTF-8 TTML XML document

Converts timing to second-based begin and end attributes

Converts cue line breaks to elements

Escapes ampersands and angle brackets in text nodes

Processes files up to 50 MB without uploading them

Why Convert?

TTML stores cues as structured XML rather than WebVTT text blocks.

Some streaming, broadcast, and localization tools accept TTML input.

A basic TTML draft can be extended with profile metadata in an XML editor.

XML tools can validate and transform the timed text.

Converting locally avoids uploading program material or caption text.

Keeping VTT and TTML copies supports different delivery environments.

Scenarios

Common Use Cases

Basic TTML Draft

Create a basic TTML document from web subtitles before checking it against a target profile or workflow.

XML Interchange

Move timestamped VTT cues into a tool that accepts TTML XML input.

Text Editing

Use XML-aware tools to inspect or edit cue timing and text.

Local Conversion

Convert subtitles without uploading them to a separate conversion service.

Web and TTML Copies

Keep a VTT version for web playback while producing a basic TTML copy for another workflow.

Format Ecosystem

Related Formats

SRT

A simpler timestamped subtitle format that is widely supported by media players.

VTT

The readable web-video input format used by this converter.

ASS

A styled subtitle format for players and workflows that need detailed presentation controls.

How It Works

1
Select or drop a .vtt file; its contents stay on your device.
2
The parser finds timestamped cue blocks and reads their text.
3
Cue identifiers, settings, regions, comments, and CSS blocks are discarded.
4
Start and end milliseconds become values such as begin="1.500s".
5
Line breaks become elements and XML special characters are escaped.
6
Each cue is written as a element inside the TTML body.

moreTools.fromFormat

VTT LRC VTT SRT VTT TXT VTT ASS VTT SCC VTT STL VTT SMI

moreTools.toFormat

SRT TTML ASS TTML LRC TTML SBV TTML SSA TTML SCC TTML STL TTML SMI TTML

More Subtitle Tools

Subtitle Format Cleaner

Remove formatting, tags and noise

Subtitle Editor

Edit subtitle content and timings

Subtitle Sync & Timing Calibration

Adjust timing with millisecond precision

Subtitle Merger

Combine multiple subtitle files

AI Subtitle Translator

Translate to 19 built-in target languages

Frequently Asked Questions

No. VTT cue settings, regions, CSS, and inline styling tags are not mapped to TTML styling or layout attributes. Tags inside cue text are escaped and remain literal text.

Voice tags are not converted to TTML spans. Their angle brackets are escaped, so the source markup appears as literal text in the generated element.

No. The generated TTML contains the XML declaration, default namespace, xml:lang="en", body, div, and timed elements. It does not include head, styling, region, IMSC, ITV, or EBU-TT-D metadata.

Each cue start and end is written as a three-decimal second value, such as begin="1.500s" and end="4.000s".

No. NOTE blocks do not contain displayable cue text for this converter and are ignored.

Not by itself. Platform profiles often require additional namespaces, metadata, styling constraints, and validation. Use this basic TTML as a starting point only and check the recipient specification.

Ready to convert your subtitles?

Drop your VTT file here and convert to TTML instantly.

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Related Resources

What is VTT?What is TTML?VTT vs TTML ASS vs TTML SRT vs TTML SRT vs VTT