Skip to content

TTML to ASS Subtitle Converter

Extract TTML cue timing and text into an Advanced SubStation Alpha document.

Drag & drop your TTML file here

or click to browse

Supports .ttml, .itt, .xml files up to 50 MB

Core Engine Architecture

Free Online TTML to ASS Converter

This converter reads <p> cues from a TTML document and writes an ASS file with timing and text. Supported begin, end, and duration values are converted to ASS centiseconds, <br/> elements become line breaks, and common TTML inline tags are removed. The output uses a single default ASS style rather than mapping source styling.

Payload & Syntax Inspector

TTML to ASS Code Syntax & Structure Inspection

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

Millisecond Sync
input.ttml
TTML SOURCE
<?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>
output.ass
ASS RESULT
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.00,0:00:04.00,Default,,0,0,0,,Hello, world!
Dialogue: 0,0:00:04.50,0:00:08.00,Default,,0,0,0,,This is a subtitle file.
Dialogue: 0,0:00:08.50,0:00:12.00,Default,,0,0,0,,Converted locally!
Specification Sheet

TTML vs ASS Technical Specifications

Standard Compliant
Input Format

TTML

TTML

TTML (Timed Text Markup Language) is an XML subtitle format. This converter looks for <p> elements with begin and end, or begin and dur, timing attributes. It accepts second-based values such as 1.500s and clock values such as 00:00:01.500. Cues without a begin attribute are skipped.

Output Format

ASS

ASS

ASS (Advanced SubStation Alpha v4+) is a text subtitle format with script information, styles, and Dialogue events. This converter creates a complete basic ASS document with one Default style, Arial 20, and a 1920x1080 play resolution. Source styling is not mapped.

Format Differences

TTML is XML; ASS is a sectioned plain-text format.
TTML uses begin, end, and dur attributes; ASS Dialogue lines use Start and End fields.
TTML timing is converted to ASS centisecond precision.
TTML source styling is discarded; the ASS output uses one Default style.

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 TTML <p> cues with begin/end or begin/dur timing
Converts timing to ASS H:MM:SS.cc centiseconds
Turns <br/> elements into ASS line breaks
Removes common TTML inline formatting tags
Creates a complete basic ASS document with a Default style
Processes files locally in your browser

Why Convert?

ASS is a convenient editing format when you need to continue timing or restyling work.
ASS has broad support in desktop subtitle editors and renderer ecosystems.
The output uses a predictable default style rather than requiring source styling to be rebuilt.
Converting TTML text and timing can make the cue list easier to inspect and edit.
Scenarios

Common Use Cases

Subtitle Editing

Move TTML cue text and timing into ASS for additional editing in a subtitle editor.

Restyling

Use the generated Default-style ASS document as a clean starting point for custom styling.

Timing Cleanup

Inspect converted start and end times while preserving cue text and line breaks.

Format Ecosystem

Related Formats

SRT (SubRip)

Convert TTML to SRT for a simpler plain-text subtitle format.

VTT (WebVTT)

Convert TTML to VTT for a basic web-video cue format.

TTML (Timed Text Markup Language)

Keep TTML when your destination requires the original XML structure or metadata.

How It Works

  1. 1

    Select or drop a TTML file.

  2. 2

    The parser extracts each <p> element and its timing attributes.

  3. 3

    End time comes from end, or begin plus dur; otherwise a three-second fallback is used.

  4. 4

    Text entities are decoded and line breaks are normalized.

  5. 5

    Cues are written as ASS Dialogue lines using the Default style.

moreTools.fromFormat

TTML SRTTTML VTTTTML LRCTTML TXTTTML SCCTTML STLTTML SMI

moreTools.toFormat

SRT ASSVTT ASSLRC ASSSBV ASSSSA ASSSCC ASSSTL ASSSMI ASS

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. Common inline formatting tags are removed during parsing, and the ASS output uses one Default style.

ASS timing is written to centisecond precision. Fractional milliseconds beyond that precision are truncated.

No. Processing stays in your browser and the subtitle file is not uploaded.

If end is present, it is used. Otherwise dur is added to begin. If neither is present, the converter uses a three-second fallback duration.

Yes. There is no registration or watermark, and conversion happens in your browser.

They are skipped because the converter cannot determine their start time.

Ready to convert your subtitles?

Drop your TTML file here and convert to ASS instantly.

Related Articles

Convert YouTube JSON3 Subtitles to SRT, VTT, or LRC | AllSubConverter

Download YouTube captions as JSON3 and convert them to SRT, VTT, or LRC. Step-by-step guide covering yt-dlp, the JSON3 format, and free online conversion.

4 min read

Add Pinyin & Furigana to Subtitles | AllSubConverter

Learn how to add pinyin to Chinese subtitles and furigana to Japanese subtitles. AI-powered reading aids for language learners, karaoke, and study materials.

2 min read

Related Resources

What is TTML?What is ASS?ASS vs TTMLASS vs LRCASS vs SBVASS vs SCC