During September 2025, Hajin Chung focused on stabilizing hardware-accelerated video decoding in the FFmpeg/FFmpeg repository by addressing a memory management issue in the QSV initialization flow. He implemented a targeted fix in C, resolving a reference-count leak in avcodec/qsvdec by ensuring the temporary hardware frame context is properly released after use. This change reduced memory growth and the risk of leaks during long-running transcoding jobs, directly improving reliability for QSV-enabled workflows. His work demonstrated a strong grasp of C programming, memory management, and video processing, contributing to more stable and maintainable code in the hardware decoding path.