H5MD is a file format specification, based upon HDF5, aimed at the efficient and portable storage of molecular data (e.g. simulation trajectories, molecular structures, ...).
The first official release of the specification will contain particle trajectories (positions, velocities, forces and species) as well as thermodynamical observables. Afterwards, extensions will be considered on the basis of discussion with users of H5MD.
H5MD is developed by Pierre de Buyl, Peter Colberg and Felix Höfling and is available under the GNU General Public License.
The draft represents the current state of the specification.
If you want to know more about or contribute to H5MD, please visit the project page of H5MD at https://savannah.nongnu.org/p/h5md/ or join the mailing list at https://lists.nongnu.org/mailman/listinfo/h5md-user.