ABC O&O stations running two 720p sub-channels

In article ,
wrote:

Nor am I. Perhaps your authoritative definition of HD will
enlighten us all?
You would agree that less than 10 mbps MPEG2 a/v conforms to
DVD, yes?
Thus my logic: if it fits on DVD, plays on DVD, it must be a
DVD. Is there any dispute about DVD quality vs. HD quality?

I am not saying you are wrong that the quality of the picture
will suffer at a reduced bitrate. Obviously it will. I just
don't know that we should redefine what hd is.

Chip

http://en.wikipedia.org/wiki/High-definition_television

Quote:

"The optimum format for a broadcast depends upon the type of
videographic recording medium used and the image's characteristics. The
field and frame rate should match the source and the resolution. A very
high resolution source may require more bandwidth than available in
order to be transmitted without loss of fidelity. The lossy compression
that is used in all digital HDTV storage and transmission systems will
distort the received picture, when compared to the uncompressed source."

So: Take away available bandwidth, and you take away the ability of the
system to deliver peak image quality when required. Instead, you force
more and more lossy compression, which means forcing more and more
distortion. The lower the available bandwidth, the more distortion you
cause both in amplitude and in frequency of need.


Also taken from that article:

"In practice, the best possible HD quality is not usually achieved. The
main problem is that many operators do not follow HDTV specifications
fully. They may use lower bitrates or smaller resolution to pack more
channels within the limited bandwidth, reducing video quality." The
reference to that links to an article on DirecTV, but it looks like the
OTA broadcasters are taking their cues from cable and satellite
companies, no? Cut the bitrate, get more channels in there.

At some point, it's not HD. If it fits within the DVD spec, we either
define it as not HD (current situation) or re-define DVD as being HD
quality.

Me, I don't like taking the label and slapping it onto something of
lower quality, and then pretending it's still the same thing.

Elmo P. Shagnasty wrote:

Nope. They're still calling them HD, but HDTV as specified originally
is going away.

A minimum Mbps was never specified. If you have a source that says
otherwise, please share it.

And that's becoming accepted, according to you.

How is something "becoming accepted" if it doesn't exist?

Elmo P. Shagnasty wrote:

I find it very amusing that a couple of years ago, when I predicted that
the bandwidth would be allocated for more subchannels and that picture
quality would take a back seat to that, that it wouldn't be about an HD
picture at all, I was called....drum roll, please....a troll.

You never made this prediction. Give us a valid message ID.

Now that it's coming to pass and I point that out, here you go again.

Now that *what* is coming to pass? Some ABC O&O stations reducing the
bit rate of their HD channel?

In article ,
Wes Newell wrote:

HD as originally defined is a picture with at least 720p. There's no
requirement for a bitrate.

Wow, so you'd accept *any* bitrate as being HD, as long as it met the
720p or 1080i spec?

Wow.

CLicker wrote:

I am not aware of bitrate being used to define hd.
If you have that information, please post it.

Chip

Nor am I. Perhaps your authoritative definition of HD will
enlighten us all?
You would agree that less than 10 mbps MPEG2 a/v conforms to
DVD, yes?
Thus my logic: if it fits on DVD, plays on DVD, it must be a
DVD. Is there any dispute about DVD quality vs. HD quality?

Hard to make that statement since DVDs are only 480, not 720 or 1080. And
don't be confused: While the 650nm laser on DVD players can read at a
maximum of 10.5 Mbps, actual DVD video is but a portion of this. The
average rate for video and audio is less than 4.7 Mbps, not 10 Mbps.

Elmo P. Shagnasty wrote:

You may not have, but our little friend Elmo has tried.
He claims that having two hd streams on one channel
isn't hd.

YOU'RE the one who's saying it IS.

And yet it's being pointed out to you that what's being delivered could
actually have come from a DVD!

Is DVD now HD? Are you making that definition??

DVD audio/video averages less than 4.7 Mbps. What channels advertised
as HD are as low as 4.7 Mbps?

You may make up whatever definitions you like for anything you like, if
it makes you feel better.

It won't mean it's true, or that you can communicate with anyone else in
the world, but you may do what you like.

Looks to me as if *you* are the one making things up such as your statement:
"They're still calling them HD, but HDTV as specified originally is going
away." To what original HDTV specification are you referring?

Ron Chapman wrote:

At some point, it's not HD. If it fits within the DVD spec, we either
define it as not HD (current situation) or re-define DVD as being HD
quality.

As stated, DVD audio/video averages less than 4.7 Mbps. AFAIK, no channel
claiming to be HD even approaches that level.

Me, I don't like taking the label and slapping it onto something of
lower quality, and then pretending it's still the same thing.

So, where do we draw the line? 12 Mbps HDTV is compressed, yet NBC
uses that rate in Prime Time. PBS's, ABC's, and Fox's 14-15 Mbps is
compressed. Even CBS's 18-18.5 Mbps is compressed. Yet I bet NBC gets
no more complaints than does CBS. So *where* would you draw the line?

wrote in message
...
"CLicker" wrote:

Neither of us has defined what it is, nor referred to any
authoritative definition! How can we be redefining that?

You may not have, but our little friend Elmo has tried.
He claims that having two hd streams on one channel
isn't hd. I am only asking for proof that reducing the
bitrate low enough to have two channels means that by
definition they are not hd. That's all.

Chip

If the bit rate were reduced further, say 5 streams per channel,
would it still be HDTV if nothing else is changed?

It would be unreasonable for DVD, HDTV, or Blu-Ray to specify a
minimum bit rate, as all of these support variable bit rates.
The physical medium, disc and spin rate or 8vsb, dictates the
upper bit rates. Thus, some other factor needs to draw the line
between VHS, SD, and HD. Clearly it's not frame size nor bit
rate. But it can't be as objective as merely what it looks
like, can it?

Is there no threshold for HDTV beside aesthetics?

CLicker wrote:

It seems simple enough. Two streams in an OTA broadcast channel
will average less than 10 mbps. Thus, the average a/v would be
high quality, widescreen DVD, certainly not HD (unless of course
h.264 were employed rather than MPEG2).

How do you figure, since DVD audio/video averages a maximum of 4.69 Mbps?

On Fri, 01 May 2009 14:50:40 -0400, Elmo P. Shagnasty wrote:

In article ,
Wes Newell wrote:

HD as originally defined is a picture with at least 720p. There's no
requirement for a bitrate.

Wow, so you'd accept *any* bitrate as being HD, as long as it met the
720p or 1080i spec?

Wow.

Wow what, that's correct. As long as the display has 720 scan lines, it's
HD by definition. The bit rate means nothing in that regard. With modern
and yet to be developed codecs, you can have a lower bit rate without
loss of picture quality.

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