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"DjVuLibre: Open Source DjVu library and viewer"
DjVuLibre DjView (or simply DjVuLibre) is an application used to open and manipulate DjVu files. The DjVu file format is an increasingly common one, typically used as an alternative to PDF because its compression technologies result in smaller file sizes. DjVu documents, however, cannot be opened on PDF readers: the same goes for DjVu images. A dedicated DjVu viewer is needed, and that is where DjVuLibre comes in.
DjVuLibre can be used as a standalone viewer, although it also functions as a plugin for web browsers (much like Adobe’s own PDF Reader software) so that DjVu files online can be displayed on a browser window. DjVuLibre actually comes with decoders as well that can be used to convert DjVu documents into other file formats if needed. It also comes with an image compressor, as well as a number of other tools that let users put together their own DjVu documents. There is also a portable version of the program named DjView4, which can be used as a standalone viewer with multiple navigation, document search, and page view settings. Both are open source and available for no cost.