I usually buy ebooks through Humble Bundle, download all formats and then import them into calibre. For 2 of 3 formats the metadata will be extracted without pr

I usually buy ebooks through Humble Bundle, download all formats and then import them into calibre. For 2 of 3 formats the metadata will be extracted without problems. Only one is usually lacking. I think it's mobi or epub, but never bother to pin it down because I just combine then in one entry anyway, and then the metadata will be merged together. Calibre has usually no problem with extracting metadata from files, independant from the source.