Patent ID: 7783772

Claim:
One or more computer readable storage media having stored thereon a plurality of instructions for generating a session description message that describes properties of a multimedia presentation to be streamed to a client device, the plurality of instructions, when executed by one or more processors, causing the one or more processors to: access an ASF file header of the multimedia presentation; identify a subset of a plurality of objects of the ASF file header; generate, for each object in the subset of the plurality of objects, a different one of a plurality of extensions for the session description message that are separate from the ASF file header, the plurality of extensions including: a caching information extension that specifies information about caching of the multimedia presentation, the information identifying whether the multimedia presentation can be cached, a length the multimedia presentation is considered fresh, when cached copies of media streams of the multimedia presentation are considered stale, whether to use a stale cached copy of a media stream, and whether to determine if a newer version of the media stream is available when the media stream is stale; an encapsulation extension that specifies codec initialization parameters for one or more of a plurality of different codecs; and a bandwidth sharing extension that is separate from the ASF file header and that specifies media streams of the multimedia presentation that share bandwidth such that a maximum bandwidth of the specified media streams is less than a sum of maximum bandwidths of each of the specified media streams; and for each object in the subset of the plurality of objects: retrieve one or more parameters from the object, and use the retrieved parameters as the parameters for one of the plurality of extensions.