Multimedia applications over the Internet and Internet Protocol Television (IPTV) gain a lot of attention. IPTV has a number of service requirements such as; high bandwidth, scalability, bounds on delay, jitter and channel zapping time. IP multicast, IP Multimedia System (IMS) Protocol and peer-to-peer (P2P) approaches are proposed for implementing IPTV. However, IP multicast requires all the routers in the core network to possess multicast capability, IMS does not easily scale and P2P cannot efficiently utilize the network resources because of its completely distributed nature. To this end, we propose Cluster Based Application Layer Multicast (ALM) IPTV (CALMTV) which is a new application layer multicast protocol for live IPTV. CALMTV combines application layer multicast, scalable video coding and probing techniques to meet live IPTV requirements. We present the components and their relevant algorithms of CALMTV. The performance of CALMTV is demonstrated with ns2 simulations. Our experiment results compared with the published results of other ALM architectures, which can support IPTV, show that CALMTV improves end-to-end delay and zapping time with respect to these architectures withou significant increase of jitter.