These are some links to high definition multicasts.  These are 20-25 Mbps streams, and require multicast to work.  To see if your connection is multicast-enabled, use the multicast tester at Multicast Technologies.  

To use links below:
  1. Install VideoLAN (before you start the download, look for the University of Wisconsin-Madison mirror for fastest download).
  2. Click on a link below.  The first time you do this, your computer will not know how to display files with the extension VLC, and will ask you.  Browse to the VLC application, and choose it.
  3. Unicast versus IP multicast
    1. With unicast, one stream leaves the server for each viewer.  Unicast connections work on-campus and off-campus, over DSL and cablemodems.
    2. With multicast, one stream leaves the server no matter how many viewers.  Multicast connections only work on the campus and at other universities or institutions with advanced networks.  DSL and cablemodems do not support multicast.
      1. Multicast only works on wired connections. 
      2. Multicast DOES NOT WORK 
        1. on WiFi or wireless connections.
        2. on UW campus wireless.
        3. on DSL service.
        4. on cablemodem service.
        5. using WiscVPN.
  4. Global versus local scoping
    1. Multicast addresses starting with 239 are locally-scoped...That means that they stop at the UW-Madison campus border router and can not be seen elsewhere on the Internet.
    2. Multicast addresses starting with 233 are globally-scoped...That means that they can travel past our border router and across the Internet.
  5. Progressive scan, Interlacing and Deinterlacing
    Interlacing is used to compress data.  Half of the lines are sent at a time, first the odd lines, then the even lines, and these interlace with each other.  When displaying video on an LCD computer display, the lines are displayed in a progressive (non-interlaced) way.  When motion occurs with interlaced video, some items on some lines appear in different locations, giving them jagged edges.   De-interlacing is a mechanism to reduce the visibility of these jagged edges.  VideoLAN has several settings for Deinterlace, which can be found under the Video menu.
Dave Devereaux-Weber
dave@doit.wisc.edu
15-July-2009