At the risk of upsetting everyone by adding to my own post One of the big attractions in M/C is not having to have a server. On
Internet 2 theres a regular stream (sorry) of M/C trials using boxes like the Visionary Solutions, QVidium or Vbrick, to multi-cast direct from an appliance. These aren't too expensive, and Amino makes a range of real cute set top boxes, that are very affordable. they also work at HD levels, around 10Mbps for 1080i.
There are cute apps like DVTS. They take the DV video frames (25Mbps), wrap ip around them and biff them onto the network in either a point to point unicast, or multi-cast. We did once run it between VUW and CityLink, but it does require 40Mbps. It isn't efficient on bandwidth, but great on CPU. It will run on most laptops. So you can multi-cast off a laptop a tru-ish broadcast video signal. Its at the lowest end of broadcast standard. (altho News will play anything if its interesting) The industry is heading to HD and things aren't quite so easy. Currently an HD camera puts out 1.4Gbps SDI and is fiber connected. There are the cheap HDV cameras that use firewire and achieve video at 19Mbps. There is a version of DVTS apparently (very hard to find) that will shift the HDV frames. The problem is HDV is MPEG compressed with long GOP, so you need a decent machine to de-compress. VLC will shift HD using MPEG-2, but once again you're into compression and the CPU requirements go up. The 1080i/10Mbps figure I quoted was for 1080i heavily compressed. Currently we struggle to do it live. 720p is OK, but 1080i is just a bit too hard. We use a quad core with a HD-SDI feed at 1.4Gbps. We will try a 8-core CPU when money allows (sponsors are very welcome). (we can do MPEG, but the bandwidth is heavy and MPEG servers also pricey - hence multi-cast) For the HD TV you watch, its typically shifted using MPEG-2 either over satellite at 26Mbps, or over fiber using a Tandberg encoder at 96Mbps. (So all "big" venues need fiber.) the links are all point to point, using distribution amps at the international broadcast centers. Its all HD-SDI. The costs are staggering - A typical HD truck is $25M. A camera chain without lenses is around $300K. A typical rugby match has 17+ cameras. But considering the feeds go to NZ, Aust, SA, UK, Can, USA and EU, the audience is large and the revenues also large. And the really challenging bit is that 1080p is now available, running at 3Gbps. So watch what you do when buying that new plasma or LCD screen for Christmas. So how do we run 100K+ feeds of 3Gbps to the rugby mad homes of Wellington ? R