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Sky -+?

(April 2008)

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BH
Bvsh Hovse
Hymagumba posted:
jason posted:
No particular reason why that shouldn't work, but they'd need to tie it to their own ISP, or download the file over satellite (not really feasible because of the bandwidth required for unicast traffic).


sorry I should have been more clear. My idea ran on the concept of the download being sent over satellite rather than over the net.


Ah right. Technically possible, you can data over DVB-S. But the bandwidth isn't there to do it. Let's say a typical satellite channel is encoded at around 4Mbps (I know I'm being generous in some cases there, but anyway) and you wanted to transmit highly compressed video at 1Mbps instead.

Well you could either transmit 8 videos in twice the time it takes to play them, 4 videos in real time, or one video at 4 times playback speed in that space used to transmit that channel. Then scale the figures up to work out how many simultanious requests you want to be able to handle and how long you want people to wait. Once a few hundred people start using the service you'll realise that you need to shut down most of the channels on the EPG in order to provide a decent service level.
:-(
A former member
Bvsh Hovse has eloquently explained why the satellite approach isn't feasible so I'll leave there.

The only way a satellite approach will scale is by broadcasting the traffic, as they are doing now with Anytime in effect.

You only have a few hundred channels now -- a downloaded film would use up an entire transponder for several minutes, and times that by only a few hundred users and the whole thing breaks down.

It is for this reason that VoD over the net doesn't scale either. Not unless you are planning on charging for the service, and sending data over your own network.

Satellite is a broadcast medium by definition -- not unicast. So is cable fundamentally.

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