How are VTT regions handled?

VTT REGION blocks define areas for cue display. The converter maps VTT regions to TTML elements in the section of the document head, preserving the positioning intent from the original VTT file.

Are timestamps accurate after conversion?

Yes. VTT already uses dot-separated timestamps (00:01:30.500), which align directly with TTML time expressions. The converter wraps them in begin/end attributes with no precision loss.

Can I convert VTT to TTML for Apple TV?

Yes. Apple TV uses ITV, a TTML-derived format. The TTML output is compatible with Apple TV delivery requirements, though you should verify against Apple's ITV profile specification.

Is the VTT to TTML converter free?

Yes, completely free with no sign-up, no watermarks, and no file size limits. All processing happens in your browser.

What happens to multi-line VTT cues?

Multi-line cues in VTT (separated by newlines within a single cue) are converted to TTML elements with tags between lines. This preserves the visual line break structure in valid XML.

Does the converter escape XML special characters?

Yes. Characters like ampersand, angle brackets, and quotes in the subtitle text are escaped to XML entities (&, <, >, ") automatically, ensuring the output is valid parseable XML.

How does this differ from SRT to TTML conversion?

VTT has richer features than SRT (cue settings, voice tags, NOTE comments, regions) that require additional handling during conversion. The SRT-to-TTML path is simpler since SRT is plain text. Both produce the same TTML output format, but the VTT path preserves more styling and metadata.

Can I edit the TTML file after conversion?

Yes. TTML files are XML documents. You can edit them in any text editor, XML editor, or professional subtitle tool like Subtitle Edit, OOONA, or EZTitles that supports TTML.

Absolutely. All conversion happens client-side in your browser. No subtitle data, file contents, or metadata is ever sent to a server.

What file extension does the output use?

The output uses .ttml by default. For Netflix delivery, you may rename it to .itt. For broadcast EBU-TT-D delivery, .xml is sometimes used. The file content is the same regardless of extension.

Does the converter handle VTT inline styling tags?

VTT supports inline tags like , , , and within cue text. These are mapped to TTML span elements with appropriate tts: styling attributes in the output.

Can I batch convert multiple VTT files to TTML?

This page processes one file at a time. For batch conversion, use the Workspace feature to load multiple VTT files and process them through the pipeline sequentially.

What about VTT chapter cues?

VTT files can contain chapter information (using the CHAPTER keyword). These are treated as regular cues during conversion and wrapped in TTML elements. If you need chapter metadata preserved separately, export chapters independently.

VTT to TTML Converter

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VTT

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!

TTML

<?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>

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About VTT to TTML

This converter transforms WebVTT (.vtt) subtitle files into TTML (Timed Text Markup Language) format. WebVTT is the modern web standard for HTML5 video, but streaming platforms like Netflix, Apple TV, and Amazon Prime Video require the XML-based TTML format for professional delivery. This converter bridges that gap, handling VTT-specific features like cue settings, NOTE comments, voice tags, and the WEBVTT header during conversion.

Input Format

VTT

VTT (WebVTT) is the W3C standard for HTML5 video captions with dot-separated timestamps (00:01:30.500), cue identifiers, NOTE comment blocks, voice tags (<v Speaker>), inline cue settings (position, align, line, size), and a mandatory WEBVTT header. It is used by YouTube, Netflix web, Vimeo, and all modern browsers.

Output Format

TTML

TTML (Timed Text Markup Language) is a W3C XML-based subtitle format used by Netflix (IMSC), Apple TV (ITV), Amazon Prime Video, and broadcast systems (EBU-TT-D). TTML provides structured XML with namespace declarations, inline styling, positioning, language metadata, and complex multi-region layouts for professional delivery.

Features

Converts VTT dot-separated timestamps to TTML begin/end XML attributes

Strips WEBVTT header, NOTE blocks, and cue identifiers during processing

Maps VTT inline cue settings (align, position, line) to TTML tts: styling attributes

Preserves VTT voice tag speaker labels as span elements in the output

Generates complete TTML XML with namespaces, head, styling, and body sections

Converts VTT text newlines to tags for valid XML line breaks

Escapes XML special characters automatically for valid output

Client-side processing - no uploads, no server, complete privacy

Why Convert?

Netflix requires IMSC (a TTML profile) for subtitle delivery and will not accept VTT through its content partner portal, even though Netflix web player can display VTT.

Apple TV and iTunes use TTML-derived ITV format, not VTT, for all subtitle assets in their ecosystem.

Broadcast EBU-TT-D delivery requires XML-based subtitle files, and VTT is not accepted by EBU-compliant broadcast systems.

Amazon Prime Video content partners must deliver TTML, not VTT, for subtitle assets through the Amazon Video Direct portal.

Professional localization and captioning workflows require TTML's structured XML, metadata capabilities, and styling precision that VTT cannot match.

TTML supports forced narrative flags and SDH (Subtitles for Deaf and Hard of Hearing) metadata that VTT does not encode, needed for accessibility compliance.

VTT's styling capabilities are limited compared to TTML's tts: styling attributes, which support complex positioning, regions, and multi-line alignment for professional captioning.

Format Differences

VTT timestamps use dots (00:01:30.500). TTML uses XML attributes begin="00:01:30.500" end="00:01:35.000" with the same dot format but wrapped in XML attribute syntax.

VTT starts with a mandatory WEBVTT header line. TTML starts with an XML declaration and <tt> root element with namespace declarations.

VTT uses NOTE blocks for developer comments and cue identifiers for referencing. TTML has no equivalent; comments and identifiers are stripped during conversion.

VTT supports voice tags (<v Speaker Name>) for speaker labeling. TTML uses elements for the same purpose.

VTT cue settings are inline on the timestamp line (align:left, line:50%). TTML uses tts: attributes on individual elements or defined in the <styling> section.

VTT regions are defined with REGION blocks. TTML uses <region> elements in the <layout> section of the document head.

Common Use Cases

Netflix Web-to-Platform Upgrade

Netflix's web player uses VTT, but its content partner portal requires IMSC/TTML for delivery. Convert VTT subtitles to TTML when submitting content to Netflix for streaming.

Apple TV Delivery from Web Source

If your subtitles are authored in WebVTT for web distribution, convert to TTML before delivering to Apple TV and iTunes, which require ITV format.

Broadcast EBU-TT-D Conversion

European broadcast systems require EBU-TT-D (a TTML profile). Convert web-standard VTT subtitles to TTML as the foundation for EBU-compliant broadcast delivery.

Professional Captioning Handoff

Captioning vendors and localization studios require TTML for professional workflows. Convert your VTT subtitles to TTML when handing off to professional captioning or localization teams.

Accessibility-Compliant Delivery

TTML supports SDH metadata and forced narrative flags that VTT cannot encode. Convert to TTML when delivering accessibility-compliant subtitles for streaming platforms.

Related Formats

SRT

SubRip - the simpler plain-text alternative to VTT. Convert SRT to TTML when you do not need VTT's web-specific features.

VTT

WebVTT - the input format for this converter. The modern W3C standard for HTML5 video subtitles.

ASS

Advanced SubStation Alpha - a feature-rich subtitle format for anime and karaoke. Convert ASS to TTML for streaming platform delivery.

Frequently Asked Questions

Why convert VTT to TTML when both are W3C standards?

VTT is the W3C standard for web video playback, while TTML is the W3C standard for subtitle authoring and interchange. Streaming platforms like Netflix, Apple TV, and Amazon require TTML for professional delivery even though their web players can display VTT. TTML provides the XML structure, styling precision, and metadata that professional delivery workflows require.

What happens to VTT NOTE blocks?

VTT NOTE blocks are developer comments (notes about timing, speaker changes, or production notes) and are stripped during conversion. TTML has no direct equivalent to VTT NOTE blocks, so they are removed from the output.

Is the WEBVTT header preserved?

No. The WEBVTT header (the mandatory first line of every VTT file) is removed during conversion. TTML documents start with an XML declaration and <tt> root element instead.

Does the converter handle VTT cue settings?

Yes. VTT inline cue settings like align, position, line, and size are mapped to TTML tts: styling attributes. For example, VTT's 'align:left' becomes tts:textAlign="left" on the element in the TTML output.

How are VTT voice tags converted?

VTT voice tags (<v Speaker Name>) are used to label dialogue by speaker. The converter preserves the speaker label by wrapping the text in a element within the TTML , so speaker information is maintained.

Does the converter produce Netflix-compatible TTML?

Yes. The output TTML follows the standard TTML 1.0 structure with proper namespaces. For Netflix IMSC compliance, verify against their latest delivery specification for any additional profile-specific requirements.

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Related Resources

What is VTT?What is TTML?