This repository provides the data pipeline for the Sekai dataset, a large-scale egocentric video dataset for world exploration and generation research. It contains two main toolchains: dataset_downloading (extracting YouTube URLs from CSV annotations and downloading videos via yt-dlp) and clip_extracting (a multi-step GPU-accelerated pipeline to split raw videos into annotated clips, transcode them to H.265, and remux with audio). The pipeline is designed for the Sekai-Real subset and requires NVIDIA GPUs with NVENC support, CUDA 11.8, and specific Python dependencies. The code is well-structured with clear separation of steps, logging, and multiprocessing support. While tightly coupled to the Sekai dataset and hardware requirements, the utility modules for GPU video decoding/encoding and frame sampling are reusable in other video processing projects.