Systems and methods for providing dynamic changes to a packet flow in a communication network are described. The dynamic changes can include upgrading and downgrading quality of service (QoS), adapting the stream to a receiving device, modifying the stream to counter-act changes in an air interface, and modifying the stream to accommodate an inter-technology handover. These changes can be provided by inspecting packets at a gateway and setting up a proxy for multimedia stream packet flows. The proxy can coordinate transcoding to take place to change the stream. The gateway can also monitor conditions at the mobile node using a real time control protocol or other applicable protocols.