The description of epub format expansion
The epub file is a digital electronic book stored via the EPUB algorithm, an open XML-based mechanism for digital publications and books. It provides an ordinary format specified for digital publications and intended to the consumers and publishers. EPUB-files can be opened with supporting hardware devices, such as the Sony Reader and PocketBook, and software programs.
The EPUB extension is related to three open-based standards, which are all supported by the International Digital Publishing Forum (IDPF):
- The Open Container Format (OCF), that makes a single package out of all the the ebook files into a compressed view;
- The Open Packaging Format (OPF), that makes a description of the whole ebook structure;
- The Open Publication Structure (OPS), which makes a definition of the content markup.
A lot of commercial books contain digital rights management (DRM) protection. Those file objects can only be revealed on gadgets that have been authorized for the ebook viewing.