Mastering means the creation of a set of bytes which are to be transferred to media. This set of bytes is called "image". Mastering may happen simultaneously with media writing or it may happen separately into a buffer file on hard disk.
One class of images are ISO 9660 filesystems for which libburnia provides its mastering software libisofs. These filesystems are usable read-only with all contemporary operating systems. Our program xorriso offers a command line interface for creating and manipulating images on optical media or in disk filesystem objects.
Other classes of images may be archive formats like afio or star which
have an own knowledge about their end-of-archive (tar has not), or various
filesystems which are specific to particular operating systems.
libburnia offers no mastering software for these but is willing
to bring them onto media by libburn, cdrskin,
or xorriso.