With the accelerating spread of MPEG-4 AVC and second-generation DVB modulation for both SD and HDTV distribution to the home (DTH) in many markets, is backhaul of sports and news contributions back to the studio advancing at the same rate? It depends on the market, as the rollout of HD is the real driver for change. In terms of satellite backhaul, up until the last two years, the rate of adoption of MPEG-4 AVC and DVB-S2 has been at a much slower pace in the contribution market. This was in part because there was not a great enough incentive initially to upgrade to MPEG-4 AVC encoders and DVB-S2 modulators. A significant difference in backhaul operations compared with DTH distribution is the use of constant bit rate (CBR) coding rather than variable bit rate (VBR) coding. VBR is used for DTH transmission where there are a bundle of services within a multiplex. Statistical multiplexing optimizes bandwidth usage per channel as the data demand can vary on a frame-by-frame basis for any channel in the stream. It therefore makes the most cost-efficient use of data bandwidth on a service-by-service basis.