What it does
ttconv converts subtitle and caption formats through a command-line application and library. It supports formats including SCC, EBU STL, SRT, IMSC/TTML, and WebVTT, with format-specific settings.
Run the CLI with input/output paths and optional explicit formats, then apply JSON reader/filter/writer settings. Conversion passes through a TTML/IMSC-based canonical model; EBU STL is input-only in the listed matrix. Frame-based IMSC timing needs a rational frame rate, while SCC output distinguishes drop-frame and non-drop-frame modes. The LCD filter removes most formatting, and the IMSC 1.1 filter checks major deviations rather than acting as a complete validator. The same pure-Python reader/model/filter/writer architecture is exposed as a library.
Strengths
- Exposes timing and presentation settings across several caption standards.
Watch out for
- Supported input and output format lists differ.
Best for
- Technical subtitle and broadcast-caption conversion