ASS to TTML Subtitle Converter
Transform Advanced SubStation Alpha subtitles into TTML format instantly and privately in your browser.
Drag & drop your ASS file here
or click to browse
Supports .ass files up to 50 MB
Free Online ASS to TTML Converter
Our ASS to TTML converter reads Advanced SubStation Alpha input and produces Timed Text Markup Language output entirely in your browser. Source ASS timing (H:MM:SS.cc centiseconds) is converted to TTML timing (seconds (1.500s) or clock values). Styling and markup that the target format cannot represent are normalized or stripped, leaving valid, ready-to-use output. The conversion runs client-side, so your subtitle files are never uploaded to a server.
ASS to TTML Code Syntax & Structure Inspection
Side-by-side code inspection illustrating header definitions, timestamp syntax, and cue payload formatting
ASS vs TTML Technical Specifications
ASS
ASS (Advanced SubStation Alpha v4+) is an extended subtitle format used heavily in anime distribution. It features a [Script Info] header, a [V4+ Styles] section defining fonts, colors, outlines, and shadows, and an [Events] section of Dialogue lines carrying inline override tags such as {\pos}, {\blur}, and {\fad}. Timing uses centisecond precision (H:MM:SS.cc). ASS supports positioning, vector drawing, and karaoke effects.
TTML
TTML (Timed Text Markup Language) is an XML-based subtitle format standardized by the W3C and used by Netflix, Apple TV, and broadcast delivery. TTML stores captions in <p> elements with begin/end timing expressed as seconds (1.500s) or clock values, supports rich styling and regions, and is the basis of the IMSC and ITT profiles.
Format Differences
Conversion Troubleshooting & Gotchas
Practical solutions for player compatibility, character encoding, and timing synchronization
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.
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.
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.
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
Why Convert?
Common Use Cases
Streaming Delivery
Produce TTML subtitles for Netflix, Apple TV, and broadcast delivery workflows; validate the recipient specification before submission.
Professional Interchange
Use TTML as the rich, validatable interchange format for professional timed-text pipelines.
IMSC / ITT Profiles
Generate TTML that serves as the basis for IMSC and iTunes Timed Text delivery.
Related Formats
SRT (SubRip)
The universal plain-text alternative: convert to SRT for maximum device compatibility.
VTT (WebVTT)
The web alternative: convert to VTT if your target is HTML5 video or YouTube.
SCC (Scenarist Closed Captioning)
The North American broadcast alternative: convert to SCC for CEA-608 caption delivery.
How It Works
- 1
Upload your .ass file by dragging it in or browsing.
- 2
The parser reads the Advanced SubStation Alpha structure and extracts each cue's start, end, and text.
- 3
Source ASS timing (H:MM:SS.cc centiseconds) is converted to TTML timing (seconds (1.500s) or clock values).
- 4
Styling and markup are normalized for TTML, and cues are formatted to the TTML specification.
- 5
The output .ttml file is generated and ready to download.
More Subtitle Tools
Frequently Asked Questions
It reads an Advanced SubStation Alpha file, parses each cue's timing and text, normalizes the structure for Timed Text Markup Language, and writes a valid .ttml file. Source ASS timing (H:MM:SS.cc centiseconds) is converted to TTML timing (seconds (1.500s) or clock values).
Absolutely. Every conversion runs client-side in your browser. No subtitle data, file contents, or metadata is ever transmitted to a server.
ASS and TTML both support styling, but their styling models differ. Styling that cannot be mapped is normalized or dropped, while dialogue text and timing are always preserved.
Yes, completely free with no sign-up, no watermarks, and files up to 50 MB each. All processing happens in your browser, so your files are never uploaded to a server.
Source ASS timing (H:MM:SS.cc centiseconds) is converted to TTML timing (seconds (1.500s) or clock values).
Yes. The converter is fully responsive and works in any modern mobile browser on iOS and Android.
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