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Local HDTV Info and Reception > Denver, CO - OTA
dhett's Avatar dhett 01:30 PM 02-08-2012
Quote:
Originally Posted by GE AVS View Post

What you are describing was most likely not a problem originating at KUSA - again, I observed no problems OTA on my recent vintage TVs (both low end and high end TVs using either powered rabbit ears or an attic antenna and in a signal challenged area). However, it is a common problem with tuner cards, DTV converter boxes and older HD TVs. Having personally observed the pixilation (macro blocking) problems with various devices through the years, it is almost always associated with one of the described above peripheral devices and older HD TVs. And it is almost always more evident on a 1080i broadcast such as KUSA's broadcast.

I noticed the problem here in Phoenix with the local broadcast. I was watching OTA on a 1080p-capable 46" Philips HDTV that I bought in Jan. 2008 - is that what you're referring to as "older"? I notice it on 1080i broadcasts but not 720p.

kucharsk's Avatar kucharsk 02:24 PM 02-08-2012
I may have missed mention of this, but I finally have a device that can tell me channel formats, and it says 3-1 is sending its RTN programming in 720p?

It also said KWGN is sending 2-1 in 720p, but I thought CW was always 1080i.

I could see 3-1 as an error on their part, but i'm wondering if 2-1 went 720p as part of the merger with long-time 720p 31-1.
kucharsk's Avatar kucharsk 02:35 PM 02-08-2012
If you want to see horrid macroblocking on KUSA a reliable source is the credits at the end of SNL.

All the people on stage combined with the credit scroll is a recipe for disaster.

Should make the Olympics fun; anyone else remember how spectacular the SLC games looked on zero subchannel KUSA back in 2002?
GE AVS's Avatar GE AVS 02:57 PM 02-08-2012
Quote:
Originally Posted by mrvideo View Post

I disagree 100%. Macroblocking is not something that is caused in playback. It is a result of lack of bits to fully describe the 16x16 block in question, at the encoding stage. In other words, it is also called bitstarving, or being bitstarved.

You cannot, under any circumstances, bitstarve playback. Sure, there can be playback issues with computers. I see it all the time with high bitrate H.264 feeds. But, never ever do the playback issues result in macroblocking.

Users with tuner cards can capture the program and I can guarantee that if the program has macroblocks, they are in the transmission. Proof of that is to view the captured file with a program that allows single frame viewing and frame captures. If macroblocking was a playback issue, due to lack of CPU power etc., there would not be an issue if one were to freezeframe the video. But, the macroblocking will not go away upon a freezeframe and said macroblocking can then be saved as a JPG or PNG, whatever image file.

I, and many others, have provided samples of bad local station encodings in various threads on AVS.

I didn't address the issue you have brought up nor did I say that it couldn't happen, that, yes, one can have bit starvation from the encoding end at a station. I have actually created bit starvation on purpose in encoding/PSIP configuration tests on-air from master control while watching the outgoing video vs. the demodulated OTA signal.

However, many a time, I have had two different brands of TVs side by side feeding from the same antenna with very different results from high motion video. And, I have seen a less expensive generic brand outperform a major brand although that is not usually the case.

I think you may have not understood my point about the transcoding from 1080i to 720p (or to 1080p). That process is inherently non-linear as interlaced video cannot be directly converted into a progressive scan due to the every other line offset of the two fields in interlaced video, which would be a temporal impossibility. Thus, the transcoding algorithm has to create a pseudo progressive scan as it rebuilds the pixel structure which is unique to each hardware manufacture. The process takes considerable processing power. Depending on processing speed of the chips (both CPU and memory) and the complexity of the algorithm, there can be processing bit starvation within that process within the device.

And note in your discussion, one cannot have a freeze frame of an image until after the decoding process at the tuner/TV has occurred. Thus, the question is, when did the macro blocking (bit starvation) occur. If I'm not seeing bit starvation off air in master control or on my TV in home, but someone else is experiencing the problem on their device/system, where is the problem occurring?

Bit starvation can occur anywhere (including at the camera) in a digital capture, processing, and delivery system.
mrvideo's Avatar mrvideo 03:47 PM 02-08-2012
Quote:
Originally Posted by dhett View Post

I notice it on 1080i broadcasts but not 720p.

1080i requires more bits than 720p. But 720p can be bitstarved as well. My local ABC affiliate has two sub-channels and reserved space for mobile and their stuff looks like sh!t.

ATSC can barely handle 1080i on a good day (no subchannels or orther crap).
mrvideo's Avatar mrvideo 06:16 PM 02-08-2012
Added note: What needs to be known is if the viewer is watching via cable, DirecTV or Dish. All three are known to recode and overcompress in order to allocate more streams per mux. Therefore OTA might not see anything, but others could when not watching via OTA.

EDIT: This posting was supposed to appear after the next one.
mrvideo's Avatar mrvideo 06:16 PM 02-08-2012
Quote:
Originally Posted by GE AVS View Post

However, many a time, I have had two different brands of TVs side by side feeding from the same antenna with very different results from high motion video. And, I have seen a less expensive generic brand outperform a major brand although that is not usually the case.

Interesting

Quote:


I think you may have not understood my point about the transcoding from 1080i to 720p (or to 1080p). That process is inherently non-linear as interlaced video cannot be directly converted into a progressive scan due to the every other line offset of the two fields in interlaced video, which would be a temporal impossibility. Thus, the transcoding algorithm has to create a pseudo progressive scan as it rebuilds the pixel structure which is unique to each hardware manufacture. The process takes considerable processing power. Depending on processing speed of the chips (both CPU and memory) and the complexity of the algorithm, there can be processing bit starvation within that process within the device.

The display device should not be working in the MPEG-2 realm if taking 1080i to 720p or 1080p for display. It should be working in raw baseband video, which can't have macroblocks. On my computer systems I use the RGB/VGA connector from the Nvidia graphics card. The program to do the displaying is VLC. It, unfortunately, still does not use the CUDA capability of the Nvidia onboard display GPU to handle video decoding. That means it is still doing it via software. When it can't handle the high bitrate H.264 video, it drops frames. It doesn't make a mish-mash of the video. It doesn't have any problems with 37 Mbps MPEG-2 video.

Quote:


And note in your discussion, one cannot have a freeze frame of an image until after the decoding process at the tuner/TV has occurred. Thus, the question is, when did the macro blocking (bit starvation) occur. If I’m not seeing bit starvation off air in master control or on my TV in home, but someone else is experiencing the problem on their device/system, where is the problem occurring?

Correct. After decoding and the freeze frame shows macroblocking, that means it was a result of the station's encoder, not with any playback or decoding on the computer. Doing a freeze frame, as a result of single frame stepping cannot result in CPU overloading while decoing, as it can take all the time it needs.

Damn good question. I'd have to be at the place of the person complaining and doing visual imspections and personal captures and frame looking.
Trip in VA's Avatar Trip in VA 07:31 PM 02-08-2012
Quote:
Originally Posted by kucharsk View Post

i'm wondering if 2-1 went 720p as part of the merger with long-time 720p 31-1.

It did.

- Trip
GE AVS's Avatar GE AVS 08:43 PM 02-08-2012
Quote:
Originally Posted by mrvideo View Post

1080i requires more bits than 720p. But 720p can be bitstarved as well. My local ABC affiliate has two sub-channels and reserved space for mobile and their stuff looks like sh!t.

ATSC can barely handle 1080i on a good day (no subchannels or orther crap).

A few months ago Denver's ABC affiliate (V7/RF7) went to four sub-channels - 1 HD & 3 SDs. Amazingly, it is working very well. I have yet to see any macro blocking on HD on my high end 120Hz OTA HDTV and only a very few instances of macro blocking on a generic 60 Hz counter top HDTV on rabbit ears.

The Cheyenne, WY CBS affiliate recently switched from 1080i with one HD & one SD to 720p with two HD (both CBS - one programmed for Cheyenne and one programmed for Northern Colorado) AND a SD carrying the CW network. When I can get a solid signal (not often), surprisingly it appears to be working OK.

The CBS O&O Denver affiliate is 1080i with one HD program sub-channel with TVGOS data. It is rock solid. To say ATSC can barely handle 1080i is not true with today's technology.
GE AVS's Avatar GE AVS 09:15 PM 02-08-2012
Quote:
Originally Posted by mrvideo View Post

Interesting



The display device should not be working in the MPEG-2 realm if taking 1080i to 720p or 1080p for display. It should be working in raw baseband video, which can't have macroblocks. On my computer systems I use the RGB/VGA connector from the Nvidia graphics card. The program to do the displaying is VLC. It, unfortunately, still does not use the CUDA capability of the Nvidia onboard display GPU to handle video decoding. That means it is still doing it via software. When it can't handle the high bitrate H.264 video, it drops frames. It doesn't make a mish-mash of the video. It doesn't have any problems with 37 Mbps MPEG-2 video.



Correct. After decoding and the freeze frame shows macroblocking, that means it was a result of the station's encoder, not with any playback or decoding on the computer. Doing a freeze frame, as a result of single frame stepping cannot result in CPU overloading while decoing, as it can take all the time it needs.

Damn good question. I'd have to be at the place of the person complaining and doing visual imspections and personal captures and frame looking.


Everything that is happening in the transcoding is happening as a digital process prior to the actual physical display process. The freeze frame "video" is read out of digital memory. The bit starvation can be happening anywhere in any of the digital processes.

And I note that as I previously mentioned, this seems to happen a lot with viewers using tuner cards. Sure enough, you are. And folks with tuner cards on computers seem to have the most problems. And I see more visual problems when I use a tuner card with my computers.

The bottom line for me based on my personal experiences and observations is that the average tuner card is just not as robust and capable as a well designed higher end HDTV, especially ones with scan rates of 120 Hz or higher which have superior processors and algorithms.

BTW, does anyone know of a tuner card or stick with higher than a 60 Hz vertical scan rate?
GE AVS's Avatar GE AVS 08:48 AM 02-09-2012
Quote:
Originally Posted by dhett View Post

I noticed the problem here in Phoenix with the local broadcast. I was watching OTA on a 1080p-capable 46" Philips HDTV that I bought in Jan. 2008 - is that what you're referring to as "older"? I notice it on 1080i broadcasts but not 720p.

Dave, it's hard to identify any particular vintage of equipment other than older equipment generally will have more problems decoding ATSC signals. Like all things CPU based, each new generation of hardware or new version of software seem to make improvement in the ability of devices to process ATSC OTA signals. And with OTA, there are many variables that can affect the MPEG-2 transmission stream and its decoding including signal strength (and its strength variability), multipath distortion causing cancellation and/or errors (e.g., flying aircraft, blowing leaves and branches, temperature inversions), general error rates of the digital data, impulse noise, and general signal-to-noise ratio of the broadcast data stream, for example. Anything lowering the performance of these parameters can further cause problems in the decoding and transcoding processes. And transcoding from 1080i into pseudo 720p or 1080p prior to final display will require even more processing power when intaking a problematic data stream and may well exceed the ability of the system to process the data, i.e., not enough bits to process the data, especially on high motion video.
TC AVS's Avatar TC AVS 06:06 PM 02-10-2012
Quote:
Originally Posted by GE AVS View Post

Everything that is happening in the transcoding is happening as a digital process prior to the actual physical display process. The freeze frame "video" is read out of digital memory. The bit starvation can be happening anywhere in any of the digital processes.


This is correct.
TC AVS's Avatar TC AVS 06:16 PM 02-10-2012
Quote:
Originally Posted by mrvideo View Post

Added note: What needs to be known is if the viewer is watching via cable, DirecTV or Dish. All three are known to recode and overcompress in order to allocate more streams per mux. Therefore OTA might not see anything, but others could when not watching via OTA.

I agree. It IS important to distinguish from whom is the signal received.

In Denver, Comcast has fiber tie-ins to 4, 6, 7, 9, and 31. Beyond that, I don't know. Comcast does sometimes take in a feed OTA to redistribute, but as a rule they rely on fiber from the various master control centers.

Dish and DirecTV rely on OTA feeds from local broadcasters.
TC AVS's Avatar TC AVS 06:33 PM 02-10-2012
Quote:
Originally Posted by TC AVS View Post

RMPBS does have a translator, fed from the KTSC-Pueblo content system, serving Coaldale and Cotopaxi. There is also a translator serving the adjoining Salida area. Canon City, unfortunately, remains unserved.

KTSC-Pueblo serves 10 of the 25 translators in the RMPBS system, and has one of the longer licensed microwave shots in the area: Fremont Peak (northwest of Canon City) to San Antonio Peak 10 miles in to NM at the southern end of San Louis Valley.

A possible point of correction: The RMPBS translator in contention is on what is labeled in Google Earth as "Methodist Mountain" bordering Salida -- or at least, the other side of the saddle of Methodist Mountain. The city of license for this translator is Salida. This translator does not look down upon Canon City.

Fremont Peak is listed in Google Earth as bordering Canon City. There is a transmission site there.

Industry RF techs have called the mountain across the saddle from Methodist Mountain "Fremont Peak". I was quoting others who may have been quoting others who quoted others, ,who quoted....

Any geography buffs out there? What's your take on the two points on Methodist Mountain, separated by a saddle?
ppasteur's Avatar ppasteur 06:25 PM 02-13-2012
Hey guys,
Just back to this..
Yes I used the wrong terms. This is ancient history now.
But yes, easily seen on the 60" LG Plasma and even more so on the PC tuner card and 27" Samsung from two feet away. Smearing, micro blocking, little jagged edges during motion, loss of resolution on the background, whatever the proper terms are, it did not make me happy. Compared to games I have seen on Fox and KMGH in the past, It sucked.

I am a veteran of the Tower Wars and an antenna 60 feet in the air to get KMGH on their coathanger antenna. And yes, I saw Super Bowls from them that looked better way back then.



I also saw content on PBS from the Republic Plaza when they ran a HI Def loop using all that HDTV had to offer...

In any case, I was watching OTA, I have D, and looked at that for a bit, but it gets no better than the source. The signal meter for KUSA on the HR24 is pegged at 100% btw. The WinTV HVR 2250 card shows 28 for the SNR and usually shows 0 to 5 correctable errors and 0 uncorrectable errors. I now have a Winegard 7696P 35 feet up on a rotor. I can see lookout mountain form here at about 13 miles. I don't have a signal problem.

As to credibility, I am not expert, just one of the guys that has been around this board for a long time and seen quality for HDTV, come and go. Judging by this game...it has gone...Regardless of whether it was the network or KUSA, I did not like what I saw. Just my thoughts.

One last thing, why should anyone have to question my credibility when , for one, I am not looking for any, and two, I am just reporting my thoughts and feelings on what I saw ???

So, I just wanted to rant. That used to be acceptable in this thread...

Phil

Quote:
Originally Posted by johnty View Post

I was watching OTA. Maybe macro blocking is the wrong word, micro blocking might be closer. I was viewing the game on my PC monitor with a tuner card and 1080x1920 resolution from about two feet. At this range, every defect is very visible. Any movement and the picture would break up severely. I first noticed this with KRMA which has had the same phenomenon at different times as they played with their bit-rate. NBC, CBS and ABC have always had better pictures than KRMA but KUSA has taken the lead in poor quality.

I was only referring to satellite bandwidth from what I've read about both Dish and Direct allocating more bandwidth to a channel when they want to give the viewer the best possible picture.

I don't keep track of the number of sub-channels the locals are broadcasting. It is apparent, though, that the 'HD' channel keeps getting further away from the 19.4 Mbps possible. Leno always looks worse than Letterman.

Mobile can now take up to 6Mbps, the weather loop adding to the loss. The numbers don't matter. Such picture break-up used to be minimal. Now it's major. As 'ppasteur' said, you'd think PQ would be important to them.

Evidently not.


Trip in VA's Avatar Trip in VA 06:11 AM 02-14-2012
Looks like KRMA is preparing to move from Mount Morrison back to Lookout Mountain.

- Trip
kucharsk's Avatar kucharsk 07:34 AM 02-14-2012
Quote:
Originally Posted by Trip in VA View Post

Looks like KRMA is preparing to move from Mount Morrison back to Lookout Mountain.

- Trip

I'd say "that would be nice" but really I haven't had any issues receiving KRMA with my antenna pointed at Lookout.
madkins's Avatar madkins 10:22 AM 02-14-2012
Quote:
Originally Posted by Trip in VA View Post

Looks like KRMA is preparing to move from Mount Morrison back to Lookout Mountain.

- Trip

A few days before they filed their construction permit application, they filed an application for an STA at Lookout. From their STA application:

Quote:


The STA operation proposed by this application is necessitated by the impending loss of KRMA-TV's licensed transmitter site due to lease considerations. RMPBN therefore is in the process of completing plans for a permanent relocation of the KRMA-TV facility. Accordingly, RMPBN is currently preparing to file a construction permit application for the necessary changes, and following FCC authorization will pursue the build-out and implementation of the KRMA-TV facility modifications. In the meantime, however, RMPBN seeks STA to operate a reduced power KRMA-TV facility from an alternate antenna site in order to maintain service to the station's community of license and surrounding area during the process of dismantling and relocating the KRMA-TV transmitting facility. A grant of STA will therefore serve the public interest by allowing RMPBN to continue KRMA-TV's noncommercial educational DTV broadcast service for local viewers until it can complete the facility change process in connection with the station's long-term relocation needs.

The STA is for 114 kW @ 182 meters above average terrain versus 750 kW @ 292 meters for the CP.

If they have to operate using the STA facilities for too long the lower power and antenna height might cause some folks some trouble, I suppose.

Looks like the STA application is for the LCG tower. The more permanent facilities would be a little farther west.
jsmar's Avatar jsmar 12:40 AM 02-15-2012
Quote:
Originally Posted by madkins View Post

Looks like the STA application is for the LCG tower. The more permanent facilities would be a little farther west.

So does anyone know if the new antenna location will be on a new tower or will it be on one of the older towers? I'm not sure what the status of the older towers are at this point. I believe all the LCG analog towers were taken down with the possible exception of KTVD's tower. Does KRMA's old tower on Lookout still exist?

EDIT: OK, I guess I should have just read the application. KRMA is returning to their old analog tower on Lookout Mountain. At one time Jefferson County wasn't going to allow them to do that, but the Federal Exemption probably lets KRMA ignore that problem.
pkeegan's Avatar pkeegan 11:36 AM 02-15-2012
It has probably been discussed at length (search wasn't very helpful) but is Fox31 planning on correcting their daytime bit starvation. Occasionally I see it at night but it is quite prevalent during the daytime at both my house and my parents.
dkreichen1968's Avatar dkreichen1968 07:25 PM 02-15-2012
Quote:
Originally Posted by pkeegan View Post

It has probably been discussed at length (search wasn't very helpful) but is Fox31 planning on correcting their daytime bit starvation. Occasionally I see it at night but it is quite prevalent during the daytime at both my house and my parents.

I haven't seen anything I would consider to be bit starvation on Fox31, and I watch quite often. What shows seem to be the problem?
pkeegan's Avatar pkeegan 11:20 AM 02-16-2012
The afternoon court shows. I have good signal strength 95% as does my parents. I'm calling it bit starvation , the picture lags the sound then tries to catch up with lots of breakup.
Don_M's Avatar Don_M 08:15 PM 02-16-2012
Quote:
Originally Posted by pkeegan View Post

... the picture lags the sound then tries to catch up with lots of breakup.

Sounds like it could be multipath interference, or perhaps incipient signal overload. Either one, or both working together, can cause reception problems like these. What make and model antennas are you and your parents using, and where are they located?

EDIT: Where are you/they in relation to Centennial Airport? If it's between you and the towers, airplanes flying through the signal paths can make a hash out of reception as well. The place is extremely busy during daylight hours, but air traffic falls off sharply after dark.
pkeegan's Avatar pkeegan 11:06 AM 02-17-2012
Parents are at Broadway & Arapahoe with a Radio Shack small indoor UHF/VHF antenna. I'm at Holly & County Line. I have a DB4 in my attic and a DB2 outside for 2 different TVs which exhibit the same issue.
Don_M's Avatar Don_M 05:52 PM 02-17-2012
Quote:
Originally Posted by pkeegan View Post

Parents are at ...

Scratch the airport, then. It was a likely culprit only if both your homes were east of it, or directly under the flight paths. You've got me stumped as to a cause, particularly in three different antenna locations like that. It's time for trial and error:

If your parents' antenna is amplified, the booster can cause signal overload, or worsen multipath. If it is, try a simple pair of un-amplified VHF/UHF rabbit ears instead. (They may not be pretty, but they almost always work better than "sleek" antennas do.)

If you've amplified either or both of the DBs at your house, try removing the amps (and power injectors, if applicable) and run the cables directly to the TVs. If not, all I can suggest is incremental adjustments to aim, height and location to see if moving the antennas helps at all.
pkeegan's Avatar pkeegan 10:16 AM 02-18-2012
Thanks for your suggestions.
None of the antennas are amped. Guess I will try readjustments when the weather gets better.
Thanks.
dkreichen1968's Avatar dkreichen1968 10:03 AM 02-20-2012
Quote:
Originally Posted by Don_M View Post

Sounds like it could be multipath interference, or perhaps incipient signal overload. Either one, or both working together, can cause reception problems like these. What make and model antennas are you and your parents using, and where are they located?

Don,

Do you think that the dB antennas could have enough gain to overload the TV tuners that close in?

I find it interesting that he is only reporting problems with KDVR, since KDVR is on RF32 with KWGN on RF34 and KCNC on RF35. I'd expect the same problem with them.
Don_M's Avatar Don_M 03:57 PM 02-20-2012
Quote:
Originally Posted by dkreichen1968 View Post

Do you think that the dB antennas could have enough gain to overload the TV tuners that close in?

Impossible to know for sure without going to this guy's and his parents' houses armed with a spectrum analyzer, of course. Two of the three antennas in question are indoors, so that's a fair amount of attenuation right there. Only the DB2 is outside. The apparent reception difference between 2.x, 4.1 and 31.x may be due to transmitting antenna locations and heights: Even though they're all on Lookout FCC data has them on three separate towers, and KDVR has the lowest HAAT of the three. The lower height, combined with the terrain around the two homes, lack of foliage, snow cover, etc., may have induced a bit of multipath interference for these viewers.
dkreichen1968's Avatar dkreichen1968 07:06 PM 02-21-2012
The reason that I thought of overload is that here in Monument I have no problem picking up the stations in question with an attic mounted reflectorless Gray-Hoverman (less gain than the DB4). Meanwhile they are basically sitting right under the towers. I'd think that either the attic mounted DB4 or the exterior DB2 would drive multiple tuners with no real problem. As far as the indoor antenna is concerned, there are all kinds of possible sources of multipath and interference.
kucharsk's Avatar kucharsk 08:16 PM 02-21-2012
Given that it happens just on syndicated programs in the afternoon, there's always the possibility that it's in the syndication feeds 31 is recording, not in the 31 signal itself.

Do you ever see it on local commercials/local promos or just during the show itself?
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