1. A computer-implemented method comprising: creating a data structure for at least one instance of a feature to be associated with one or more of a plurality of media objects in a sequence, wherein said data structure includes: a first group of one or more data fields, at least one data field of the first group of data fields storing data identifying a family of each instance of the feature and at least one other data field of the first group of data fields storing data uniquely identifying each instance of the feature; and a second group of one or more data fields, at least one data field of the second group of data fields storing a value representing a position of each instance of the feature relative to a position of an instance of at least one other feature in the family of the feature associated with the media objects in the sequence, wherein said position of each instance of the feature is dynamically determined as a function of the data identifying the family of the instance of the feature stored in the at least one data field of the first group and the data uniquely identifying the instance of the feature stored in the at least one other data field of the first group.