Shaka Player is a production-grade, client-side JavaScript library for adaptive media streaming in web browsers. It implements the full DASH and HLS manifest parsing pipelines, DRM integration via Encrypted Media Extensions, and a comprehensive plugin system for ad insertion, text display, transmuxing, and device-specific quirks. The architecture is modular with clear separation of concerns: a core Player class orchestrates manifest parsers, streaming engines, ABR algorithms, and UI controls. Key capabilities include offline storage (IndexedDB), CMCD/CMSD metrics reporting, closed captions (CEA-608/708, WebVTT, TTML), and experimental MoQT streaming support. The codebase is heavily tested with over 1,000 unit and integration tests and runs in CI against real browsers and devices (Tizen, Chromecast, Xbox). It is not a data research project; it is a reusable software library designed for embedding in web applications.