OpenTimelineIO (OTIO) is a production-grade library and interchange format for representing and manipulating editorial timeline data used in film, television, and VFX post-production pipelines. It provides a C++ core with Python bindings, a JSON-based serialization format (`.otio`), a plugin system for adapters (AAF, EDL, FCP XML, etc.), media linkers, hook scripts, and custom schemas. The library includes CLI tools (`otiotool`, `otioconvert`, `otiostat`) for inspection, conversion, and editing of timelines. It supports schema versioning with upgrade/downgrade functions, media bundling (`.otioz`/`.otiod`), and editing algorithms (trim, slice, overwrite, etc.). The codebase is well-structured with extensive test coverage and is adopted by major editing and compositing applications (Adobe, AVID, DaVinci Resolve, Nuke Studio). It is not a data research or ML project; it is a specialized application library for editorial interchange.