During this period, work focused on improving subtitle timing accuracy in the mpv-player/mpv repository. The developer addressed a critical bug by replacing llrint() with floor() for all timestamp conversions, which eliminated floating-point rounding errors that previously caused subtitles to appear early on boundary frames. This solution involved careful handling of floating-point precision, using the method floor(pts * 1000 + 1e-6) to ensure consistent subtitle display timing across platforms. The change was delivered as a single, well-scoped commit, demonstrating attention to regression risk and user-visible correctness. Core skills applied included C programming, software debugging, and video processing.