Optional dependencies are:
- libraw, libtiff, libjpeg, libpng, libheif for RAW, TIFF, JPEG, PNG and HEIF 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 recommended to install the latest version.
- ffmpeg (or libav), providing libavformat, libavutil (>= 55.20), libavcodec, libswscale and libswresample for mp4 sequence export
- libcurl for new Siril release checking online.
- gnuplot for photometry graph creation (not required at compilation time)