Abstract: The present invention is a system in which packet-switched (or general purpose network) multimedia data streaming is controlled based on the capabilities of a client and the preferences of a user. A server processor, coupled to the client processor over a packet-switched network, such as the Internet, receives client processor capabilities in association with a request for service for a multimedia type data transfer. The capabilities can be obtained by an application running on the client assessing the capabilities or through prompting of the user. The client capabilities include, for example, processor speed and multimedia encoders of the client. The server can also obtain the preferences of the user of the client processor and respond based on the preferences. Preferences include, for example, the quality of service of the transfer. The capabilities and preferences can be obtained via a query from the server to the client or can be automatically sent with each request.