QComboBox.addItems() accepts any iterable, and there's no reason to use map plus a list comprehension to operate on the same data. - input_formats will currently be lowercase, output_formats is uppercase. Without documenting this inconsistent internal API, don't rely on it. - While all builtin output plugins should have unicode_literals compatible file_type attributes, at least this assumption might break for custom plugins, so continue mapping to unicode_type. Well, at least we can reduce the number of allocated lists.
calibre

calibre is an e-book manager. It can view, convert, edit and catalog e-books in all of the major e-book formats. It can also talk to e-book reader devices. It can go out to the internet and fetch metadata for your books. It can download newspapers and convert them into e-books for convenient reading. It is cross platform, running on Linux, Windows and macOS.
For more information, see the calibre About page
Screenshots
Usage
See the User Manual
Development
Setting up a development environment for calibre
A tarball of the source code for the current calibre release.
Bugs
Bug reports and feature requests should be made in the calibre bug tracker at launchpad. GitHub is only used for code hosting and pull requests.
Support calibre
calibre is a result of the efforts of many volunteers from all over the world. If you find it useful, please consider contributing to support its development. Donate to support calibre development.