Patent ID: 7644445

Claim:
A computer-storage medium having computer-useable instructions embodied thereon for executing a method of accessing levels within a codestream comprising a plurality of scalable access types, comprising: identifying a first desired level of access among a set of first levels of a fully-ordered access type, in which each lower-ranked first level is always included within each higher-ranked first level; identifying a second desired level of access among a second set of second levels of a partially-ordered access type, in which each lower-ranked second level is not always included within each higher-ranked second level; securing authorization to access the codestream at a desired level combination comprising the first desired level and the second desired level; receiving an access node set comprising a partially-ordered set of access nodes representing a product of a fully-ordered node set representing the fully-ordered access type and a partially ordered node set representing the partially-ordered access type; receiving a single key allowing access to the codestream at the desired level combination; and using the access node set and the single key to access at least one lower combination comprising at least one of a lower-ranked first level and a lower-ranked second level.