The OPF stands for Open Package Format. This file format is actually an XML file but with .opf extension. This file format is an OEB Package Format (OPF) which might contain a digital magazine or other publication that can be read with FlipViewer. It also includes metadata that describes the content and a list of pages, images, and text referenced by the publication.
Technical Details of OPF File Format
The .opf file extension can be categorized into various types of files. It can be a file formatted with the standard set by Open Packaging. The OPFs are more than eBook files as they mostly contain information about the eBook from the title to the writer as well as other meta-information about it. This is why these files can be opened using Adobe Reading software. Also, it is used for files created by the FlipAlbum program. This program is used to create digital photo albums and these OPF files refer to the photo album created using the software. These files contain configurations of the album; its structure and image file references, and can be shared with other people as well. The OPF files are also associated with FlipBook. An OPF file can be edited with any text editor (e.g. Notepad or Notepad++) because they can be formatted using the XML format.