1. Introduction - OpenAnime/ESL GitHub Wiki

ESL is an open-source specification for a rich, human-readable subtitle format designed for advanced text presentation. It provides a comprehensive and extensible framework for defining timed text, intricate styling, and complex motion effects, making it suitable for developers building sophisticated media players or subtitle editing tools. It serves as a versatile platform aiming to elevate the standard for subtitle expressiveness beyond traditional formats.

Expressive: Implements a wide range of features including hierarchical styling, per-cue positional and rotational adjustments, karaoke-style text reveal, and multi-property motion definitions with various easing functions. Users can easily craft visually dynamic and engaging subtitles tailored to their creative vision.

Readable & Writable: Built upon HCL (HashiCorp Configuration Language), renowned for its human-centric syntax. This ensures subtitle files are intuitive to author, debug, and version control, even for users with limited coding backgrounds, while also benefiting from existing HCL tooling and IDE support for a smoother editing experience.

Structured: Organizes subtitle data into logical blocks for metadata, reusable styles, reusable motions, and individual cues. This promotes modularity and maintainability, allowing for complex subtitle projects to be managed effectively.

Precise: Aims to provide clear definitions for properties like logical pixel-based sizing and positioning relative to a reference resolution, enabling consistent interpretation across different rendering implementations.