A method and apparatus for the dynamic adjustments of video streams sent from a server to a client is provided. Using both short term and long term thinning mechanisms, the server reduces its data transfer rate when bandwidth is reduced and increases its data transfer rate when bandwidth is available. In the short term mechanism, the server will dynamically adjust the transmission rate of the video or the quality of the video based on parameters returned by the client. These parameters include currently-buffered data-size, buffered-data duration, and packet loss rate. In the long term mechanism, the server will adjust the current maximum quality level allowed depending upon the round trip times of data packets transmitted. This invention decreases client rebuffering and packet loss and increases the efficiency of available bandwidth.