What is a OPF file
The OPF file extension short for the Open Packaging Format. This is a standard type of file and is part of the EPUB e-book process. The OPF file stores a lot of information about the specific e-book. This includes information like the ID # of the book, language, creator and the title of the e-book. The OPF files are stored in the format of XML and they are part of the EPUB archive for the e-book. In order for the OPF file to function, it also needs a separate NCX XML file. This separate file contains the Table of Contents for the e-book.
The specific purpose of an OPF file is to hold information that is related to an e-book. This includes basic information about the title, language and creator of the e-book and it is kept in an XML format. In more technical terms, there are four different elements that are a part of each OPF file. These include: the guide, spine, metadata and manifest. The Metadata element contains all of the essential metadata. The Manifest element shows all of the individual files that are part of the larger package. The Spine element is responsible for keeping the linear reading order. The Guide element is optional and includes the structural components of the e-book.
Here's a small, but not exhaustive list of programs that can open OPF documents:
- Adobe Digital Editions (Windows & MAC)
- Adobe InDesign CC (Windows & MAC)
- Calibre (Windows, MAC & Linux)
- KDE Okular (Windows, MAC & Linux)
- Geometer Plus FBReader (Windows, MAC & Linux)