The traffic generated by multimedia applications presents a high degree of burstiness that can be hardly described by a static set of traffic parameters. The following paper presents a dynamic QoS negotiation scheme applied to a video streaming application. In applications that uses RSVP, the dynamic and efficient usage of the resources can be reached with the introduction of the renegotiable variable bit rate (RVBR) service, which is based on the renegotiation of the traffic specification. In this paper we describe and discuss the RVBR service and how it applies to resource reservation for Internet traffic with RSVP. For that we propose an architecture design that we evaluate by accomplishing a prototype implementation, whose performance are measured with real MPEG2 video traces. The results we obtained indicate that renegotiation is an efficient mechanism to accommodate traffic fluctuations over the burst time-scale, and that RVBR service can be easily implemented, to this aim, in real applications, using available technology.