Channel Change Delay in IPTV Systems

MPEG-based compression schemes and multicast- based nature of IPTV deployments result in channel change delay. Solutions to reduce this delay have been proposed in the literature and also in the commercial deployments. In this paper, we present an analysis of channel change delay in multicast-based IPTV systems. As video encoding parameters, more specifically the frequency of the intra-coded (I-) frames, have major impact over the channel change delay, we also investigate how different intra-coded frame frequency affects the channel change delay. In the second part of the paper, we evaluate the bandwidth penalty of using more frequent I- frames to reduce the channel change delay. Our results show that, maximum channel change delay can be reduced to around 830 msec with acceptable bandwidth penalties without using an explicit channel change acceleration mechanisms. When the delay requirement is stricter or the delay variation is not acceptable, an explicit channel change acceleration mechanism will be necessary.