The Library of Congress updates their Recommended Formats Statement regularly. This is a helpful quick reference for selecting a format that is stable when there is an opportunity to choose. If converting data from a proprietary format to an open file format results in some data loss, consider saving both. For less established or proprietary formats, consider recording the type, version, and software used to generate and play the file—this can be included in the metadata or documentation.
These guidelines may also be considered during file format selection:
13. Acquire the highest quality version of media to use for preservation
34. For EPUBs, opt for core media types, as defined by the EPUB specification