DTV Multicasting

So Why is it ok to you then to have your HD bandwidth limited by a
subchannel of stuff readily available in other places??? If there is
a storm coming, the main channel will pre-empt programming to show you
the stupid radar anyway....

dp_photography

Guys, keep the personal attacks to a minimum. However, I agree that
any subchannels degrade the main channel, as demonstrated by the
Olympic simulcast. Let's face it, 19Mbps is the bare minimum for
action and sports when using 1080i, and anything less will result in a
degraded picture and visible artifacts. Heck, I can see visible
artifacts in fast motion even when a 1080i channel is transmitting its
full bandwidth. As an aside, don't even get me started on how poor
DirecTV HD channels look with their reduced bitrates and resolution.

Jose R. Perez

How 'bout we go back to black and white TV and only
2-3 channels available in our market. Then all of you
who complain about sub-channels can have all the
bandwidth for only a couple channels.

I chimed in on this argument a while back and I'll do
it again...one of the major selling points of digital
TV was more content NOT high definition.

I guess all those who are complaining about this also
want the Internet to go back to private use so it
would be fast with no content and not users?!?

Chance Ulrich

Please... that's like saying that it would have been o.k. to for color TV to display less colors
for more channels, or for FM radio to sound like AM for more capacity. The fact is we have
a lot of channels available in our market OTA, and saying we would only have 2-3 without
subchannels is exaggerating to say the least.

You are not going to change my mind about this... so far, I have not watched any of the
subchannels we've been offered in the past because they all looked extremely poor in my
TV. It makes no difference to me to have 1 or a 100 subchannels that are sub-DVD quality,
because I will not watch any of them - they might as well not be available. If you can stand
watching poor quality signals, more power to you - I can't.

Having poor quality subchannels is bad enough, but they degrade the main channel,
particularly on 1080i signals. It's a shame that the ATSC standard was designed with such
low tolerances to reduced bitrates, but that's what we are stuck with. And yes, I am
annoyed when the picture breaks into big blocks because of reduced bitrates. Again, if you
don't notice them or are not bothered by them, more power to you, although it may be
you do not see the difference because of a smaller TV or inferior equipment. I will say that
the 720p channels seem to handle the subchannels much better - I did not see any picture
degradation when WSB had their subchannel.

Maybe we should all switch to less than 36" TVs so that we don't see the picture
degradation?

--
Jose R. Perez

Due to the fact that 720P compresses more efficiently it is far more
tolerable of a low bit rate sub channel than 1080I; that is why WSB
could get away with their sub as well as FOX. That said even 1080I can
tolerate this provided the sub channel remains at a very low bitrate but
as I recall due to various receiver designs there is a 2meg minimum
required for everyone to pick it up. I do see artifacts but do not know
if they are from the local or the national feed. That said they are
quite minimal and certainly tolerable for this viewer who simply wants
far more than what NTSC can offer me.

From what I hear on the grape vine though the future looks bleak for
quality OTA HDTV. The talk centers around an OTA cable system. As an
example for Atlanta we have about 9 DTV stations that can provide 6 sub
channels providing a potential 54 channels. We already know from
satellite that quantity wins over quality as they continue to pack in
more services further restricting bandwidth.

http://www.hdtvmagazine.com/forum/viewtopic.php?t=4175

This won