A .ssf file contains the definition of a soundset. In essence, it is a list of ResRefs for sounds to play (mono .wav files), paired with StringRefs corresponding to the text of the sound. (A StringRef of 0xFFFFFFFF indicates that there is no corresponding text.) The order of entries in the list determines how each entry is used. (For example, the second entry in the list is always a battle cry; the complete order is laid out in the soundset article.) An entry may (must) have a null ResRef when there is no sound available for the event corresponding to that entry.