On Tue, May 24, 2011 at 08:12:31PM -0400, Max wrote:
Was PBS one of the companies you are referring to? A colleague of mine worked as a developer on a project at PBS in the 90s that used the blanking interval for Internet transmissio - very cool stuff.
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The one that was _much_ more interesting was the one that Lauren Weinstein had a hand in. It piggy-backed a Usenet feed in the vertical blanking interval of several big "independant" TV stations -- ones that were carried by practically every cable company in the country. Distribution to the cable companies was via satellite, but the USENET feed, being _part_ of the video signal, consumed _zero_ additional bandwidth, and rode the satellite links for free.
To get the feed, all you needed was a TV tuner with 'video out', and the purpose-huilt decoder box that extracted the vertical interval data.
This service died as the independants moved to encrypted transmission, because the encryption did _not_ perserve anything in the 'blanking' timeslot. only the 'viewable' field-image was trasmitted, _as_ a full-field image. Sync, blanking, etc. was _locally_ generated on the receiving end.
An "elegant" idea, done in by changing technology. *sigh*
As USENIX director I sponsored and sheparded this project, called "Stargate". We at least got bits into the blanking interval at WTBS in Altanta. -- -=[L]=- Hand typed on my Remington portable Real data are normal in the middle and Cauchy in the tails.