[Nanog] ATT VP: Internet to hit capacity by 2010

Alex Thurlow alex at blastro.com
Mon Apr 21 16:26:22 CDT 2008


Chris Adams wrote:
> Once upon a time, Steve Gibbard <scg at gibbard.org> said:
>> iTunes video, which looks perfectly acceptable on my old NTSC TV, is .75 
>> gigabytes per viewable hour.  I think HDTV is somewhere around 8 megabits 
>> per second (if I'm remembering correctly; I may be wrong about that), 
>> which would translate to one megabyte per second, or 3.6 gigabytes per 
>> hour.
> 
> You're a little low.  ATSC (the over-the-air digital broadcast format)
> is 19 megabits per second or 8.55 gigabytes per hour.  My TiVo probably
> records 12-20 hours per day (I don't watch all that of course), often
> using two tuners (so up to 38 megabits per second).  That's not all HD
> today of course, but the percentage that is HD is going up.
> 
> 1.1 terabytes of ATSC-level HD would be a little over 4 hours a day.  If
> you have a family with multiple TVs, that's easy to hit.
> 
> That also assumes that we get 40-60 megabit connections (2-3 ATSC format
> channels) that can sustain that level of traffic to the household with
> widespread deployment in 2 years and that the "average" household hooks
> it up to their TVs.
> 

I'm going to have to say that that's much higher than we're actually 
going to see.  You have to remember that there's not a ton of 
compression going on in that.  We're looking to start pushing HD video 
online, and our intial tests show that 1.5Mbps is plenty to push HD 
resolutions of video online.  We won't necessarily be doing 60 fps or 
full quality audio, but "HD" doesn't actually define exactly what it's 
going to be.

Look at the HD offerings online today and I think you'll find that 
they're mostly 1-1.5 Mbps.  TV will stay much higher quality than that, 
but if people are watching from their PCs, I think you'll see much more 
compression going on, given that the hardware processing it has a lot 
more horsepower.


-- 
Alex Thurlow
Technical Director
Blastro Networks





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