Optional dependencies are:
- libraw, libtiff, libjpeg, libpng for RAW, TIFF, JPEG and PNG images import and export. The libraries are detected at compilation-time.
- FFMS2 for film native support as image sequences. It also allows frames to be extracted from many kinds of film, for other purposes than astronomy. Versions < 2.20 have an annoying bug. It is recommanded to install the last version.
- OpenCV for binned image resizing in the LRGB composition tool. Without it, only images the same size can be composed. It is also used to rotate images in the rotation tool (not yet in registration).