Worked on the flowplayer/hls.js repository to deliver a feature enhancing multi-DRM handling and playback robustness in complex media environments. Focused on refactoring the EME controller using JavaScript and TypeScript, the work enabled correct selection of DRM key systems based on PSSH data, ensuring playback reliability when only specific DRM technologies like PlayReady are available. Improved logging was introduced to facilitate faster debugging of DRM mismatches, while key ID matching and session generation were tightened to reduce playback failures. This engineering effort addressed nuanced DRM interoperability challenges and established a more resilient foundation for future media playback and DRM support.