picture moevement with HDTV

"Jan B" wrote in message
...

OP's original description of the problem was:
"Some programs I watch have this weird effect that when a subject
moves, parts of it seem to move at different times. For instance, a
face may move slightly out of synch with the persons hair ...
snip

Then someone introduced macro blocking into discussion:

Its called macro blocking - its caused by there not being enough
bandwidth being allocated by the station, and or, to much
compression
of the HD signal.
...
OTA broadcasters have the option of broadcasting 5 SD channels(480i),
or one HD channel (1080i). When they try to do an HD plus any sub
channels in SD they run out of bandwidth.
...
snip

Just for the record, I don't see the annoying issue described by the
original poster in any of the HD broadcasts I watch. For the record,
I'm in the Chicago market and only watch OTA. ...

I do not see it on many of the major network HD programing, and yes
mostly nice pictures to. The local PBS is very bad, and they are only
doing 2 sub channels. ....
snip

My understanding of what is called macro blocking is when the squares
(8x8 or 16x16 pixels?) starts to get visible.

The original problem sounds to me something that I have seen on SD
sets on TV:s using too much image processing, where filterring in the
time domain (maybe for intentional motion compensated upsampling)
introduces a lag in certain picture objects.

These objects are much larger than the macro blocks used in the MPEG
algorithm.

I've seen it only once or twice on my Philips using PixelPlus with
DNM, but that has been while upsamling SD material. (I only recently
got one HD channel, so not much statistics from that and DNM is off in
HD mode.)

What I noticed was also a person's hair that for a short while moved
seperated from the face. (No head banging was involved

Are all of you discussing this type of lag or are you talking about
macro blocking where part of (or whole) picture breaks up in squares?

/Jan

I think that's what there discussing not the macro blocking. I saw it last
night on HBO non HD and what I noticed when they zoomed in on someone's face
the more prominent features would move a bit differently than the rest of
the face so eyebrows and lips were at one speed and the face was at another.
I never noticed it until the close-ups. I never have seen this on the HD
channels or DVD's either. So either the cable company is compressing for non
HD channels and then the box is trying to upconvert to fill the void and it
picks out what it thinks is important? My guess anyway.

Rich

Rich schrieb:

I think that's what there discussing not the macro blocking. I saw it last
night on HBO non HD and what I noticed when they zoomed in on someone's face
the more prominent features would move a bit differently than the rest of
the face so eyebrows and lips were at one speed and the face was at another.
I never noticed it until the close-ups. I never have seen this on the HD
channels or DVD's either. So either the cable company is compressing for non
HD channels and then the box is trying to upconvert to fill the void and it
picks out what it thinks is important? My guess anyway.

Rich


Hello,

maybe this is an MPEG4/AVC effect because this new CODEC is
used in professional networks now, and the "object coding"
takes whole objects like faces rather then macro blocks as
is the case with MPEG2.

just my 2 cent

Klaus

"FDR" wrote in message
...
Some programs I watch have this weird effect that when a subject
moves, parts of it seem to move at different times. For instance, a
face may move slightly out of synch with the persons hair, or lips
or whatever. It doesn't happen woth movies or most programming.
The one that it happens with that comes to mind is on PBS. What
causes that?

That's mpeg compression artifacting.
http://en.wikipedia.org/wiki/Compression_artifact

On Fri, 01 Sep 2006 19:11:17 +0000, AZV14 wrote:

OTA broadcasters have the option of broadcasting 5 SD channels(480i),
or one HD channel (1080i). When they try to do an HD plus any sub
channels in SD they run out of bandwidth.

None of the stations here have trouble broadcasting 1 HD plus 1 SD
subchannels. So that's just more FUD.

HD looks great, as long as its fish slowly swimming in a tank, or a
static image. Rapid motion requires frequent image updates, and when not
enough bandwidth is available you get this annoying (well at least to me
it is), 'breakup" of the picture. Thats not a problem with SD, plenty of
bandwidth available for those channels.

And more FUD.

Some network sports use 720P to avoid the breakup problem, but then the
HD truests complain that the pictures isnt sharp enough.

Fox used to be 720p here, but recently went to 1080i. And the dvisual
difference between 720p and 1080i isn't even noticable to most eyes.

HD has nothing to do with the switch to Digital TV broadcasting BTW. The
digital mandate is for them to switch to digital transmision of SD
signals. The ability to send 5 channels in the place of one being the
economic attraction for the broadcasters - not the HD.

Not if they want to stay in business. The OTA public, like myself will not
stand for it. IOW's, if they switch to SD, they'll lose market share which
will cost them in advertising fees which drives the whole indutry. None of
what you say makeds any sense. It's all just more fud, probably started by
cable/sat companies to fool people into the false asimpyion that you get
a better quality picture over cable/sat, when in fact, it's just the
opposite. OTA is a much better picture than you get with cable or sat. All
one has to do is look at the bitrate from each to determine that. If
you're getting motion blurr, it's probably because you're watching
cab;e/sat where they cut the bitrate down to conserve bandwidth.

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On Fri, 01 Sep 2006 13:48:21 -0700, dmaster wrote:

Just for the record, I don't see the annoying issue described by the
original poster in any of the HD broadcasts I watch. For the record,
I'm in the Chicago market and only watch OTA. And I really like the
switch to digital television, and I really *love* HD OTA. }

And I think you'll hear the same from everyone everywhere that uses OTA
digital. Sounds like a few cable whores are just trying to stir the pot
with a lot of fud. Also no problems here in the DFW area where they've
been broacasting HD for ~6 years.:-)

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On Fri, 01 Sep 2006 22:58:05 +0000, AZV14 wrote:

I do not see it on many of the major network HD programing, and yes
mostly nice pictures to. The local PBS is very bad, and they are only
doing 2 sub channels. The PBS station to the south of me (150 miles
away,,digital DX rocks,,,!!!), only broadcasts 5 sub channels and no
HD at all. At least half of the other digital OTA stations in my area,
and we are a big test market, broadcast only SD sub channels - no HD
at all.

Really. Where is that and what is your zipcode?

My point isnt that technology is bad, my point is that once these
stations go all digital, they are also going to go all 5 sub channels.
Its economics, not pretty pictures, that will doom HD.

Well, I think you're full of crap. And the move in my area has been to HD,
not away from it.

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"Thumper" wrote in message
...
On Fri, 01 Sep 2006 19:11:17 GMT, wrote:

Happy to,,,

SD is Standard Definitition - essentially 480i just like you get from
a DVD.

OTA broadcasters have the option of broadcasting 5 SD channels(480i),
or one HD channel (1080i). When they try to do an HD plus any sub
channels in SD they run out of bandwidth.

HD looks great, as long as its fish slowly swimming in a tank, or a
static image. Rapid motion requires frequent image updates, and when
not enough bandwidth is available you get this annoying (well at least
to me it is), 'breakup" of the picture. Thats not a problem with SD,
plenty of bandwidth available for those channels.

Some network sports use 720P to avoid the breakup problem, but then
the HD truests complain that the pictures isnt sharp enough.

HD has nothing to do with the switch to Digital TV broadcasting BTW.
The digital mandate is for them to switch to digital transmision of SD
signals. The ability to send 5 channels in the place of one being the
economic attraction for the broadcasters - not the HD.



I don't get any "annoying breakup" of my HD picture from Comcast


We don't get any "annoying breakup" of our HD pictures on Comcast, Directv,
Dish, or over the air. Yes, we have all four.

We're happy users since December, 1999.

Thats wishfull thinking on your part,,,,,

and if you can not remain civil, and post facts, not obscenities, then
please stay off the newsgroups.


Wes Newell wrote:

On Fri, 01 Sep 2006 22:58:05 +0000, AZV14 wrote:

I do not see it on many of the major network HD programing, and yes
mostly nice pictures to. The local PBS is very bad, and they are only
doing 2 sub channels. The PBS station to the south of me (150 miles
away,,digital DX rocks,,,!!!), only broadcasts 5 sub channels and no
HD at all. At least half of the other digital OTA stations in my area,
and we are a big test market, broadcast only SD sub channels - no HD
at all.

Really. Where is that and what is your zipcode?

My point isnt that technology is bad, my point is that once these
stations go all digital, they are also going to go all 5 sub channels.
Its economics, not pretty pictures, that will doom HD.

Well, I think you're full of crap. And the move in my area has been to HD,
not away from it.

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On Sat, 02 Sep 2006 18:09:14 +0000, AZV14 wrote:

Thats wishfull thinking on your part,,,,,

At least I thought. You're just spurting crap out like it's fact when it
isn't.

and if you can not remain civil, and post facts, not obscenities, then
please stay off the newsgroups.

You've got to be kidding me. If the word crap offends you, I suggest you
stay out oif the news groups, And quit top posting. That's more offensive
than calling me a low down MF.

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I think you need to cut back on the booze when posting on the net,,,

I never called you anything of the sort,,,,

And if you don't believe it,,check the postings,,,

Now its your turn to apologize to me,,,

The facts are,,not the "crap" as you would post,,,

Present Digital Broadcasts are nothing more than prototype shake down
phases,,,hardly anyone is watching them.

Here in Phx, one of the countries biggest test markets, only 3
stations are still broadcasting commercial HD. UPN never has, WPN is
going away, and PBS plays endless fish tank loops, or the ocasional
travel show (or does the same in Wide Screen,,,which is not HD), and
all the other local stations are using all 5 subs for SD.

When analog goes away, so will HD OTA,,,,the commercial stations are
going to have to do that to survive. Ma and Pa kettle watching TV in
thier kitchen on the 13 inch TV could care less about HD,,and thats
the market, and thats the facts,,,,,

Wes Newell wrote:

On Sat, 02 Sep 2006 18:09:14 +0000, AZV14 wrote:

Thats wishfull thinking on your part,,,,,

At least I thought. You're just spurting crap out like it's fact when it
isn't.

and if you can not remain civil, and post facts, not obscenities, then
please stay off the newsgroups.

You've got to be kidding me. If the word crap offends you, I suggest you
stay out oif the news groups, And quit top posting. That's more offensive
than calling me a low down MF.

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