Video broadcast operators target a variety of receiving devices of different resolutions and processing capabilities. In such a heterogeneous TV network, the transport resource consumption is likely to increase. In this paper we estimate the required capacity for a broadcast TV network taking into account parameters as currently proposed in standardization bodies. We target constant video quality, hence the TV channel has variable bit rate (VBR). We consider a multicast-based transport system where only the required versions of a TV channel are transported. This leads to fluctuation of the consumed transport capacity over time. In order to characterize the fluctuations of the bit rate associated with one channel, we encoded a representative set of video clips. We compare a simulcast and a scalable video coding (SVC) transport scheme in several realistic examples with different encoding modes. We explore under what conditions one or the other transport scheme is more efficient.