A method and system is provided for controlling bandwidth rate limiting and client rendering rate limiting in a video delivery network. The method provides network service providers with a means for overriding video delivery data rates selected through dynamic client bitrate adaptation, as well as video data rendering rates of the clients, to limit the impact of network congestion. A system is also specified for implementing a client and a proxy computer in accordance with the method. The system works transparently with standard HTTP-based video delivery systems and includes an HTTP proxy cache infrastructure to support bandwidth rate limiting and client rending rate limiting. The system further provides for administrative overrides of client bitrate selection and client bandwidth usage.