Will HD broadcasts affect the quality of SD video?

[rjc3895]

I know this is a strange question, and I wasn't sure how to clearly state this in the title.

Anyway, while watching NFL games on Fox using my C-Band BUD, I noticed pixel distortion during fast moving scenes (i.e. terrible towels being waved, quick pans of by the camera man, etc.) I have 90 percent quality signal, and I can't recall this being a problem last year.

My theory is that, since most games are now broadcast using HD cameras, the HD signal from the cameras must go through a "down convert" mechanism in order to broadcast the standard definition (SD) signal. This would be the reverse of those DVD 'up convert' players that take an old DVD and enhances the signal to display on an HDTV.

I know that the newer HDTV sets are using new processor technologies to improve the picture during a fast action sports scene. Is the push for HDTV going to diminish the previous picture quality of standard definition (in other words will the picture be worse than pre-HDTV days?).


Any thoughts or is the problem with my old FTA receiver?

 

[voomvoom]

If you had a 20' dish, you probably wouldn't have that problem...? I think it's because the signals are weak? Most TV Stations have much larger dishes than we do, so you should see less pixelation watching it OTA, when possible....?

 

[rjc3895]

If you had a 20' dish, you probably wouldn't have that problem...? I think it's because the signals are weak? Most TV Stations have much larger dishes than we do, so you should see less pixelation watching it OTA, when possible....?

Unfortunately, city zoning laws prohibit anything over 12 ft .

As a side note (and way off topic) my property is divided into 2 separate parcels. Zoning only permits 1 BUD no larger than 12 ft on the property. So I could put one BUD on each parcel, try Iceberg's dual C-band project leaving it stationary, and motorize the other BUD.

 

[voomvoom]

20' was/is an exaggeration, 12' would do me better, as I'm at 10'. But, 12' as opposed to 7 1/2' should be a significant improvement. Also tweaking the dish, better lnb's, and maybe a few other things could improve the signal.
But, don't get me wrong, a 20' dish is an excellent idea. Wish I could get that done.

 

[skysurfer]

IMHO, SD pics look better when sourced from a HD feed (more resolution to less resolution meaning you have more data to work with to get to SD, unlike going from SD to HD where you have to add back in information through assumption - i.e. nearby pixels and what to do to get the resolution higher).

I believe you are experiencing a case of bitrate problems as configured by the uplinker - not enough bitrate for the sports carried and thus you have issues with blurriness and artifacts, etc.

 

[Radioguy41]

I believe you are experiencing a case of bitrate problems as configured by the uplinker - not enough bitrate for the sports carried and thus you have issues with blurriness and artifacts, etc.

Hummm, sounds like Dishnet. Annnnyway, skysurfer's right. If you're on FTA there are a number of feeds for the same game. I switch all around until I find the one with the best picture. There can be quite a difference in uplink quality. If you've ever recompressed an already compressed JPG image you'll know what I mean, the image bulk size gets smaller but the quality degrades. They're recompressing an already compressed feed in order to save additional bandwidth and quality suffers dramatically.

 

[brentb636]

IMHO, SD pics look better when sourced from a HD feed (more resolution to less resolution meaning you have more data to work with to get to SD, unlike going from SD to HD where you have to add back in information through assumption - i.e. nearby pixels and what to do to get the resolution higher).

I believe you are experiencing a case of bitrate problems as configured by the uplinker - not enough bitrate for the sports carried and thus you have issues with blurriness and artifacts, etc.

I tend to agree, and I'd add that the QPSK modulation is not a good choice for HD output with fast moving images, because of the limited number of data points per quadrature ( I learned these big words from the PIT channel AZCAR classes on 97W, for satellite truck techs ) . The class uses NASCAR footage to demonstrate the same datastream , but carried by QPSK, 8PSK, 16QAM and 64QAM , and shows the effects of the high speed motion on the final picture.

 

[skysurfer]

Hummm, sounds like Dishnet.

Dishnet is like that for SD (I hate watching ESPN SD on my LCD HDTV because of the artifacting of the lines on a baseball field, football field, or basketball court).

I was referring to the signals in the mux the OP was probably watching his NFL from. The bitrates are very marginal in that mux for each service (and talking heads even look bad). Those channels would look better delivered over Dishnet!

Add in NFL sports or MLB and things get worse because the bitrate is already marginal for talking heads (news) or normal network non-sports fare.

Jack up the total mux bandwidth, allocate more bitrate to each video, and you would be in better shape (but it would cost more for the extra satellite transponder bandwidth to do that).

G25 (soon G19) Ku is another home of really bad bitrate video services if you want to investigate things further (most of the international stuff looks bad) and no amount of larger dish, better LNB, better dish peaking to get more s/n is going to help things if you are on the good side of the marginal lock boundary. The only thing that would help would be things the uplinker can control (more bitrate to the mux to allocate over the existing services, or fewer services in the mux so each remaining one can have more bitrate, get the service from a better source if the fiber or atlantic ocean sat feed has poor bitrate causing the service to be poor before reuplinking, etc).

 

[boomer_106]

I tend to agree, and I'd add that the QPSK modulation is not a good choice for HD output with fast moving images, because of the limited number of data points per quadrature ( I learned these big words from the PIT channel AZCAR classes on 97W, for satellite truck techs ) . The class uses NASCAR footage to demonstrate the same datastream , but carried by QPSK, 8PSK, 16QAM and 64QAM , and shows the effects of the high speed motion on the final picture.

When and where can one view this show? That would be pretty cool.

 

[brentb636]

check out Galaxy 25, 97W.
11779 H 3979 3/4
That's the Azcar channel, and on weekdays they run classes. The schedule is a mystery to me, but I usually tune in around 10 AM .

 

[brentb636]

The class is running right now, for instance.

 

[gillham]

The class is running right now, for instance.

Ok, it sucked me in too. Good stuff!

 

[boomer_106]

Hey thanks Brent! I tuned in a little too late it looks like but, now that I've got it, I can catch it another time. I went to the website but it looks like you have to provide login information to see the schedule

 

[brentb636]

Yep, but it seems to be running, several times a day . Shouldn't be hard to catch it. I've watched several times. It varies a little, depending on the instructor, but follows the same general scheme. I recorded a session once, on my IV200, but then I sold that box, and lost the video. There is definitely information in this class that can give us a better understanding of what is happening in our hobby/curse ( FTA satellite ) .

 

[brentb636]

AZCAR is up this morning, at 11:30 .

 

[boomer_106]

I've seen a bit of it a couple of times now. I don't have much weekday, daytime tv viewing so, I don't see it alot. I did see that they were using racing. Had a woman instructor helping a TV station switch from analog to digital, I think.

 

[skysurfer]

Had a woman instructor helping a TV station switch from analog to digital, I think.

It's their microwave live truck transmissions going from analog to digital and in a different frequency band that is being taught. This course is not related to the switch of off-air tv stations from analog to digital.

 

[brentb636]

It's their microwave live truck transmissions going from analog to digital and in a different frequency band that is being taught. This course is not related to the switch of off-air tv stations from analog to digital.

The class has a good explanation of QPSK, 8PSK, 16QAM, and 64QAM modulations, and their strengths and weaknesses. I got to watch a local sat truck guy ( WOOD-TV, Grand Rapids) set up a shot last fall . They were using microwave for it, being fairly close. If it had been further away from the station, he said they'd use AMC5 for the uplink. It'd be fun to have one of those rigs.

 

[brentb636]

I've seen a bit of it a couple of times now. I don't have much weekday, daytime tv viewing so, I don't see it alot. I did see that they were using racing. Had a woman instructor helping a TV station switch from analog to digital, I think.

Next class at 7 PM EST , 7 minutes .

 

[boomer_106]

It's their microwave live truck transmissions going from analog to digital and in a different frequency band that is being taught. This course is not related to the switch of off-air tv stations from analog to digital.

Ahh ok. I caught it after it started. I was just trying to piece it together.