[extropy-chat] META: Cable Speeds and delays [was: related to SecondLife]

Brian Atkins brian at posthuman.com
Tue Dec 12 17:37:07 UTC 2006

Hi Robert,

Interesting hypothesis, but I do know a little more and that isn't how it works 
currently. In the case of "regular" channels, either analog or digital, the 
signal is semi-permanently assigned a slot in Comcast's available frequencies, 
and broadcast continuously to all subscribers at once. It's just a one way fixed 
feed, and is not interacting or competing with the internet service or 
video-on-demand that run on completely separate frequencies.

The initial lag you see in tuning channels is mostly an artifact of the MPEG-2 
compression used for the digital version of the channels. You'll see the same 
delays (compared to flipping analog channels) if you've ever had satellite tv 
service which also uses MPEG-2. It takes time when "tuning" to an MPEG-2 feed to 
build up the picture. Also HDTV over-the-air uses similar encoding, and also has 
a tuning delay.

The moral of the story is: rent a DVR from Comcast, and stop watching live tv. 
Not only do you not waste a ton of time looking for something good to watch, you 
can skip all the commercials. In the next few months in addition to Comcast's 
standard DVR, they will have a Tivo service offering available on that same box, 
and also will be coming out with a new 3-tuner box so you can record 3 things at 
once if you need even more capacity.
Brian Atkins
Singularity Institute for Artificial Intelligence

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