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

Marshall Eubanks tme at multicasttech.com
Tue Apr 22 07:10:00 CDT 2008


On Apr 21, 2008, at 9:35 PM, Frank Bulk - iNAME wrote:

> I've found it interesting that those who do Internet TV (re)define  
> HD in a
> way that no one would consider HD anymore except the provider. =)
>

The FCC did not appear to set a bit rate specification for HD  
Television.

The ATSC standard (A-53 part 4) specifies aspect ratios and pixel  
formats and frame rates, but not
bit rates.

So AFAICT, no redefinition is necessary. If you are doing (say) 720 x  
1280 at 30 fps, you
can call it HD, regardless of your bit rate. If you can find somewhere  
where the standard
says otherwise, I would like to know about it.


> In the news recently has been some complaints about Comcast's HD TV.
> Comcast has been (selectively) fitting 3 MPEG-2 HD streams in a 6 MHz
> carrier (38 Mbps = 12.6 Mbps) and customers aren't happy with that.   
> I'm not
> sure how the average consumer will see 1.5 Mbps for HD video as  
> sufficient
> unless it's QVGA.

Well, not with a 15+ year old standard like MPEG-2. (And, of course,  
HD is a set of
pixel formats that specifically does not include QVGA.)

I have had video professionals go "wow" at H.264 dual pass 720 p  
encodings at 2 Mbps, so it can be done. The real
question is, how often do you see artifacts ? And, how much does the  
user care ? Modern encodings
at these bit rates tend to provide very good encodings of static  
scenes. As the on-screen action increases, so
does the likelihood of artifacts, so selection of bit rate depends I  
think on user expectations and the typical content being down.
(As an aside, I see lots of artifacts on my at-home Cable HD, but I  
don't know their bandwidth allocation.)

Regards
Marshall


>
>
> Frank
>
> -----Original Message-----
> From: Alex Thurlow [mailto:alex at blastro.com]
> Sent: Monday, April 21, 2008 4:26 PM
> To: nanog at nanog.org
> Subject: Re: [Nanog] ATT VP: Internet to hit capacity by 2010
>
> <snip>
>
> 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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