Xiatao contributed to the FFmpeg/FFmpeg repository by addressing a decoding issue in the HEVC wasm path, focusing on low-level programming and performance optimization using C. He identified and corrected a macro typo in the inverse discrete cosine transform (IDCT) logic, restoring accurate HEVC decoding for WebAssembly builds. This targeted bug fix aligned the wasm implementation with the native path, improving decoding reliability and reducing visual artifacts in video playback. By delivering a minimal, review-friendly patch, Xiatao enhanced the stability of HEVC streams across platforms, supporting consistent user experiences and reducing potential support issues related to video encoding and decoding.