The domain section consists of two lists with entries of different length. The lengths of entries are determined by ther content.
The domain section starts with a 64 bit integer that pecifies the number of entries for the domain list. After which follows the domain list.
This list in turn is followed by a 64 bit integer that specifies the number of elements in the value domains list (the domains for values), and then the list with the value domains.
In this, one or both lists can be empty. For an empty lists only the introductory 64-bit number will be stored, which is in that case 0 .
The domain list identifies the domains of the individual elements. If a value (e.g. a variable) is outside the domain, it is rounded to a value within the domain. Values outside these domains can thus not occur for the element.
The domains for values contain also domains, but these domains only apply to actual values in elements and not for values of contained variables. The domains for values will determine how many bits are needed to store an element that contains a value. The domains for values are useful when the values of an element do not cover the full possible range of the domain for the element. For example, if a subobject contains only points whose position vectors only contain variables and integer values between 0 and 10, the domain for values for position vectors can be set to "integerB" with 4 bits, even if the variables of position vectors taking values greater 100 .
If while saving a value is found in main-Fib-object that lies outside of the actual domain of the element, the domain is automatically expanded so that it includes the value. If the domain was inherited, in the root-element a corresponding new domain is created, which includes the value and the inherited domain.
The domains for values may be generated and optimized when storing the Fib object, to keep the space for the Fib object as small as possible. A domain for values is generated when saving, if it is likely that through its generation space will be saved.
Because many domains can belong to a Fib multimedia object, for them more attention is paid to their storage space. To make future upgrades easy, the emphasis is on flexibility.
The reason for the introduction of central (in the root-elements) domains is, that on the one hand as little space as possible for values should be used when saving the Fib object, without drastically limit the assignment possibilities for the values and on other hand that it can be determined in advance if and how the multimedia object can be displayed (e.g. if and how it should be scaled or whether the display of all values is impossible). If for example, the domain for the dimension takes only integer values between 0 and 50 (e.g. the horizontal in an image), then 6 bits is enough to store the values for the dimension. For larger images simply more bits for the values of the dimension can be used.
Each entry consists of two parts: