Directed acyclic graph based source modeling for data unit selection of streaming media over QoS networks

Regardless of the network loss process, a central problem in rate-distortion optimized video streaming is the modeling of the resulting distortion associated with the loss of different subsets of data units. When the dependency among data units is modeled by a directed acyclic graph, previous work has modeled the distortion contribution of a data unit based on only two events: whether or not the data unit and all its dependent data units are available. The restriction to only two events allows the use of a single scalar to represent the distortion contribution of a data unit, and at the same time limits its accuracy. We consider the general case when a data unit can assume different distortion contributions when different subsets of its dependent data units are available. Rate-distortion optimized streaming using the general model is performed to demonstrate the possible gains.