Surprise appearance of 4-2 !

[tazman]

The whole point I was making, was not directed at the bandwidth issue, but at all the hype we get during our local news cast regarding the weather forecasts.  This is not just WTMJ, but all our locals.  WTMJ probably does it the least.  I also realize that forecasting the weather is difficult at best.  It just seems that when were expecting 1 to 2 inches of snow, all the local news media's make it out as though the Circus Parade is comming to town.  When you break it down, I guess our weather forecasters are doing their jobs the best that they can.  It's just the rest of the news team, that blows it way out of proportion.  I am old enough to remember when 4 to 6 inch or more snow falls were the norm and no one gave it a second thought.  Maybe my comment about hiring people from Canada and not from down south was a little out of line.  I appologise for that.  It's seems that the younger news crews we have now don't have any concept or perception of how our winters were just a mere 20 years ago.

If like you say, they address the bandwidth allocations correctly, then maybe it will be Ok as far as multicasting goes.

I'll give 4-2 a try and see if it is as informative as I'm hopeing it will be, without all the hype.

[John L]

But of course, Joseph screams foul on the bandwidth part. As I said before...
there is NO mandate for 16:9, high definition, over-the-air TV. Just that all over-the-air TV broadcasts go 4:3 digital by February 17, 2009. That's it.

But if he's the only one complaining and nobody else has any problems receiving NBC's  HD programming on WTMJ-TV, then maybe its an issue with his receiver?

I watched a program on WTMJ-DT last night from 8:00 pm to 9:00 pm and it was in HD and I had no problems with it.

-John L.

[kevbeck122]

I watched a program on WTMJ-DT last night from 8:00 pm to 9:00 pm and it was in HD and I had no problems with it.

When there is a lot of movement (ie: sports.. racing, etc.) you might notice more blockiness in the picture due to the decreased bandwidth on 4-1.

[murdoc]

But if he's the only one complaining and nobody else has any problems receiving NBC's  HD programming on WTMJ-TV, then maybe its an issue with his receiver?

I watched a program on WTMJ-DT last night from 8:00 pm to 9:00 pm and it was in HD and I had no problems with it.

-John L.

Joseph never said he had trouble recieving the program.  He is complaining about the bitrate loss similar to 58-1.  I have not noticed any pixalation YET (I've only watched the Office since the launch of 4-2), but I have not watched any fast-moving sports either.  Trying to watch the NFL on 58-1 it is nearly impossible to get good picture quality.  Any time there is fast-moving action, there is nothing but pixalation and macro-blocking.  1080i broadcasts NEED the full amount of bandwidth to look good.  Without it they look like complete cr@p.  A few months ago, Joseph commented on the better looking CBS picture in Boston, where they use the full bandwidth with no sub-channels.  I completely agree with him.  Thankfully with the wonderful things the internet has brought us, we DO have a choice of WHO's braodcast we watch and WHAT bitrate we watch it at.  Personally, I do not watch any of our local affiliate broadcasts, as I'd sooner pay or download in BETTER quality WITHOUT those boring commercials.

[Gilbert]

The whole point I was making, was not directed at the bandwidth issue, but at all the hype we get during our local news cast regarding the weather forecasts.  This is not just WTMJ, but all our locals.  WTMJ probably does it the least.  I also realize that forecasting the weather is difficult at best.  It just seems that when were expecting 1 to 2 inches of snow, all the local news media's make it out as though the Circus Parade is comming to town.  When you break it down, I guess our weather forecasters are doing their jobs the best that they can.  It's just the rest of the news team, that blows it way out of proportion.  I am old enough to remember when 4 to 6 inch or more snow falls were the norm and no one gave it a second thought.  Maybe my comment about hiring people from Canada and not from down south was a little out of line.  I appologise for that.  It's seems that the younger news crews we have now don't have any concept or perception of how our winters were just a mere 20 years ago.

If like you say, they address the bandwidth allocations correctly, then maybe it will be Ok as far as multicasting goes.

I'll give 4-2 a try and see if it is as informative as I'm hopeing it will be, without all the hype.

Tazman,

Nice post. I largely agree with you except on the "younger news crews". It might be because they haven't seen the snows and winters like we saw in the 1970s.
But the winters then...and now...are on the edges of what we would see in our
part of the country. I am much more inclined to believe that in this case, it is unnecessary "weather hype". However, I can also buy the argument that since people under 25 years of age or so haven't seen many major snowstorms,
it freaks them out (certainly, when I drive, I can confirm that!).

Now, others have a point about Joseph's TV. If he has an older or inferior HDTV,
he'll see more macroblocking then others. Taa-daa! Look at this month's (March 2006) Consumer Reports magazine. Wow! The quality of watching a 1080i broadcast between brands ranges from eye popping to something where Joseph would say something like this:  :mad:  :bang:  :bang:   When viewing an HDTV
broadcast, the picture depends on: 1) The quality of the image the station sends out, 2) the quality of the tuner, 3) the quality of the TV to display the image.

Just because a broadcast takes up 20 mb of bandwidth does NOT mean that if you only have 15 mb, you'll get a degraded picture. Indeed, if the video is compressed properly, you'll notice little or NO difference whatsoever. That depends on the encoders/decoders. And as I said earlier, earlier encoders have more trouble with fast/moving action.

However, I forecast that if WTMJ puts out a bad picture, Joseph will let us all know.    

Gilbert

[Joseph S]

However, I forecast that if WTMJ puts out a bad picture, Joseph will let us all know.

All you have to do is introduce movement and we get:
SNL 1 (555Kb) and
SNL 2 (448Kb)

When viewing an HDTV
broadcast, the picture depends on: 1) The quality of the image the station sends out, 2) the quality of the tuner, 3) the quality of the TV to display the image.

Macroblocking and artifacting have nothing to do with #2 or #3. Read the comments at AVS from station engineers on the Grammy broadcast. It looked crystal clear at raw, looked like crap multicast at 16Mbps, and worse than crap on CBS 58 at 15Mbps. 20Mbps is pushing the limits, but 16 and 15Mbps is going beyond what's reasonable.

Have you seen this blast from the past from CBS 1-3 while broadcasting NFL?
Dirk Nowitzki or (140Kb)
It has nothing to do with your HDTV and all to do with limited bandwidth.

[StarvingForHDTV]

Nice evidence Joseph!

Why does 36-1 display the same symptoms?  They are supposedly sending out the full bitrate.

[Joseph S]

Why does 36-1 display the same symptoms? They are supposedly sending out the full bitrate.

Because even 20Mbps sometimes isn't enough for 1080i, which is why going to 15 or 16 isn't a good idea. The better comparisons are same broadcast with different bitrates. Our Grammy broadcast had not only the blocking, but also blue and pink artifacts that even those getting 16Mbps didn't have during the intro. Our ND games had some pixelation, but not much with NBC at full bitrate. Those with a lot of pixelation on multicast ND games noted a different situation watching downloaded clips or Universal HD rebroadcasts at full bitrate.

[Joseph S]

We haven't even had the selection show, but the crapcast is already here. 58-3 is up with ads eating away yet another 1Mbps from 58-1.

[tencom]

Spatial compression also called intra compression which means data compression is applied within the video frame and a   technique to reduce the number of video levels to save data vs, temporal comression or inter frame  is  compression between successive video frames since  we use the MPEG 2
video compression standard for terrestial broadcasting in this country which is considered to be a lossy system which means that  some picture elements are lost in the compression process these losses are minimized                                                                                      by taking into account the human visual system  or not as likely to be missed by the viewer   when compression is applied some  video artiifacts are introduced some were all ready mentioned by other contributers such as pixalazation and the block effect and mosquitoing are artifacts caused by the temporal   or  interframe compression. at an insufficient data rate
 In video data reduction  to squeeze more data within   a given bandwidth  such as ch. 4.1,  4.2 controversy the more likely data compression technique of choice would be  spatiial compression  because it would  likely  be less noticed by the viewer however  one  can see     such effects such as  texturing effects or surface details being effected one example of this is green grass that looks like a green carpet instead of  natural grass when I  showed my brother HDTV video for the first time he stated that  human faces look like they were made of plastic or doll like in  appearance, and did not look natural , all because of the DCT transform that is used by spatial compression , in many instances you can tell if the video is digital or not  and the analog  will  usually look more natural.

[Mark Strube]

First off, it would help if you formed your two extremely long statements into sentences... I had quite a hard time reading that. And secondly, what does it matter? Either way it looks bad, and they shouldn't be multicasting with HD in the first place.

[Gilbert]

We haven't even had the selection show, but the crapcast is already here. 58-3 is up with ads eating away yet another 1Mbps from 58-1.

WBBM-DT in Chicago has been rumored to start that channel soon, as are
most/all CBS stations. Get used to it...24 hours of crappy promos. Now on this one, Joseph, we can agree...    :mad:  :bang:  :bang:  :bang:  :bang:

All "infomercials" and similar fare are NOT what subchannels are for! BTW, I am NOT blaming WDJT for this. CBS affiliates are being told to do this, from what I have heard.

[tazman]

Nice evidence Joseph!

Why does 36-1 display the same symptoms?  They are supposedly sending out the full bitrate.

Because that is what they get from the PBS national satellite feed.  I have noticed that in the past, and have quickly switched back and forth to see who was at fault.  I found that when there's macro blocking on 36-1, it's also on the feed.  To MPTV's credit, I have rarely seen it on their locally produced content.

[StarvingForHDTV]

Because that is what they get from the PBS national satellite feed.  I have noticed that in the past, and have quickly switched back and forth to see who was at fault.  I found that when there's macro blocking on 36-1, it's also on the feed.  To MPTV's credit, I have rarely seen it on their locally produced content.

Thanks for the information.  I will direct my question in the proper direction.  I also do not remember noticing the issue with locally produced HD content.

[Audio Gnut]

Read the comments at AVS from station engineers on the Grammy broadcast. It looked crystal clear at raw, looked like crap multicast at 16Mbps, and worse than crap on CBS 58 at 15Mbps.

Thats because when it comes down "raw", and by raw I assume you mean the satellite feed, it is at 1.4Gbps or maybe a bit higher. If someone has the correct bit rate feel free to correct me. They will not see the imperfections.

20Mbps is pushing the limits, but 16 and 15Mbps is going beyond what's reasonable.

What type of stream analyser are you using? Last I checked the ATSC standard was 19.392658Mbps + or - 50bps. Not much room for error. So if the stations are pumping out 20Mbps that could be an issue since you receiver cant handle that bit rate.

There is also something in the PSIP data called PCR. PCR=Program Clock Reference. It is basically a timing reference for your receiver. Errors in reading the PCR are called PCR jitter. Too much PCR jitter and your receiver cant process that block of information and the result is macroblocking or loss of signal errors.