Analysis of server logs from multimedia servers, a FTP server, and a web server suggest that irrespective of the content type and protocol used to retrieve it, the small percentage of files that account for the most load on the server exhibit a very dynamic popularity behavior. This observation has implications for content dissemination techniques like caching, server replication, content distribution networks, and multicast. This paper focuses on the impact of multimedia popularity on multicast scheduling. Guided by the file dynamics patterns observed in the server logs, we generate synthetic multimedia server logs with varying number of server accesses and evaluate existing multicast scheduling schemes in terms of client latency and reneging of requests. Since existing scheduling schemes do not adapt gracefully to changing access conditions, we develop MWT, a new multicast scheduling scheme. MWT is fair to all multimedia files and reduces reneging, leading to better utilization of server resources during heavy access conditions.