HDF5 (Hierarchical Data Format v5)

HDF5 is a binary file format and library for storing and accessing large, structured scientific datasets efficiently. In robotics, HDF5 is the standard container for robot demonstration datasets: a single file stores synchronized camera images, joint angles, gripper states, force readings, and metadata in hierarchical groups, with chunked I/O enabling fast random access during training. The LeRobot and ALOHA ecosystems both use HDF5 natively. The alternative Zarr format offers cloud-native chunked storage with better support for concurrent writes. SVRC's data collection pipelines output HDF5 by default.