Worked on enhancing media playback robustness in the ladybirdbrowser/ladybird repository by improving error handling within the SourceBuffer lifecycle. Focused on C++ development to ensure that the buffered() method throws an InvalidStateError when a SourceBuffer is removed from its parent MediaSource, aligning error semantics with related methods. Updated the return type to WebIDL::ExceptionOr, enabling more precise error reporting and diagnostics. This work addressed a key bug, reducing the risk of user-facing crashes in dynamic MediaSource scenarios. Emphasized consistent error handling and media source management, contributing to a more reliable and maintainable codebase for media playback features.