OTA vs BHN HD

[FTBoomerIII]

A friend of mine was ragging on me, he says that OTA HD is "TRUE HD" and that the same program on OTA and BHN are of different resolutions. Is this true?

To my way of thinking, 1080i is "True HD" is OTA 1080i?

Is BHN giving us the same resolution as OTA (ABC 720p, Fox 480p CBS ??? Discovery HD ??? HBOHD ???).

Which makes me wonder, what resolution are CBS, DHD, PBSHD and HBOHD broadcasting?

[FTBoomerIII]

Come on, someone must know the quick and simple answer to at leat some of these questions? Jaymer?

[bubblehd647]

I'd be interested in knowing if BHN is passing the compressed data stream directly from the broadcasters. Or are they are uncompressing it, then using a higher compression to feed their customers? I know there is a lot of discussion on other forums about how cable and DBS are handling the higher BW requirements of HDTV.

[bdraw]

BHN passes exactly the same Picture as OTA.
I have 2 OTA tunners, and BHN, and I see NO difference at all.

In april when BHN will give me a STB with firewire out, I can check this on a technical side as well as a visualy.

When I capture out of my firewire on my TV to my computer, The program give me all the details of the mpeg transport stream. I can tell the MB/s and the Resolution.

I do have ocasional drop outs on BHN. I replaced my Coax coming from my wall to my STB, and it helped but I still need to call a tech to come out and check my signal.

[CANDY76MAN]

I can't see any difference between ota and bhn hd either.....I have done a b comparisons several times for different channels using my rca dtc100 and bhn's pace hd box.....slight color difference but that was because of the color settings on the two different inputs on my tv, nothing to do with the signal itself.

[FTBoomerIII]

Thanks guys. bdraw, I look forward to the firewire measurments.

[bdraw]

Thanks guys. bdraw, I look forward to the firewire measurments.

I look forward to be able to record HD cable. With any luck by then BHN will carry the rest of the channels that I can pick up OTA.

I will finally be able to watch all the great HD content out there without having to sacrifice one show for another.

[passedpawn]

The compression used to limit the digital stream to something manageable has a GREAT deal to do with the quality of the show, and is likely to be the major factor in the picture quality (when comparing 720p vs 108oi, cable vs. OTA vs. satellite).

The networks compress the initial stream down from a couple of Gbps to 45Mbps (I think the camera might do this, but I'm not sure). This is the feed that the local network affiliates get. Then, it gets compressed again to 19Mbps to be sent to your home. It might be further compressed to make room for multiplexed channels.

I believe these various levels of lossy compression have a significant, and unmeasureable, effect on the detail of the picture. Since the local broadcaster (OTA, cable, and satellite) has the ability to apply their own compression to the picture, this is likely the cause of any difference we see.

The "facts" above are just my poor memory of what I have read before. I believe they are relatively accurate, tho.

[FTBoomerIII]

So, passed, are you saying that the OTA could be different if the cable companies apply another level of compression?

How can we confirm this? Greg, you around? Can you find out if this is true?

[bdraw]

This may be true. If it is we will know when they add the firewire output.
I might be able to test this using the QAM tuner built into my TV.

I will tell you that my software picks up ~19.3mb/s when recording all channels OTA except ABC, and PBS. I Haven't tried fox.
ABC it detects about 16.3mb/s and PBS various depending on which sub channel you are on. The SD is about 2mb/s and 3-5 is about 13 if my memroy serves me. I never record PBS, I just did it once as a test.

In theory I should be able to attempt to record using my QAM tuner although for some reason when I have tried this in the past, it has resulted in unwatachable video during playback. But the capture satistics should be acurate regardless.

I would put my money on BHN not doing any compression But we will see.

[passedpawn]

So, passed, are you saying that the OTA could be different if the cable companies apply another level of compression?

Yes. Or, the different broadcasters get the same signal but choose to compress it more than the next guy. Furthermore, I believe that it is necessary (or common) to de-compress it first, before you compress it again!. Ouch.

In fact, one network affiliate may look better than another with the same program: MNF might look better OTA HD in Tampa that OTA HD in Orlando. Just because of the local compression. They start with the same pic.

To add to this, the compression is quite complicated, and there is the requirement for human intervention to tweak the compression parameters. Good compression hardware & software, and possibly intelligent operators, will result in a better picture than bad. For example, the compression used on DVDs is not a push-button operation; DVD pros work with the compression software to get the best picture quality for each scene.

How can we confirm this? Greg, you around? Can you find out if this is true?
There is a person at AVS Forum (trbarry) who was working on a software utility that compared the "detail" of two images. He was doing this to compare the real resolution of two images. I don't know where this ended up, but he was impassioned with it at one time.

[bdraw]

I will tell you that my software picks up ~19.3mb/s when recording all channels OTA except ABC, and PBS. I Haven't tried fox.
ABC it detects about 16.3mb/s and PBS various depending on which sub channel you are on. The SD is about 2mb/s and 3-5 is about 13 if my memroy serves me. I never record PBS, I just did it once as a test.


I recorded Fox today OTA, the bitrate was 14.38MB/s the resolution was 704x480.

I recorded about 2 minutes of the game. It will be interesting to see if shows have the same resolutiong and bitrate. Also I thought that our fox affiliate upconverted to 720p. Not during this game atleast.

[Zimmy]

My STB Samsung TS-160 OTA ABC-HD and CBS-HD blows away my BHN versions of those channels.

It could be a bad cable connection because HBO-HD looks much better at my parents house then mine.

[passedpawn]

My STB Samsung TS-160 OTA ABC-HD and CBS-HD blows away my BHN versions of those channels.

It could be a bad cable connection because HBO-HD looks much better at my parents house then mine.
I believe the digital cable is similar to digital OTA in that it is digital and, thus, immune to color shifts and that sort of effect. I think the digital cable should degrade in macroblocks, which would be very noticeable.

What is the difference in quality that you see? I don't doubt that the OTA picture looks better than cable... I'm curious about cable-vs-cable. Are your parents in the Tampa area?

[Zimmy]

The color looks much better and there is less aliasing.
It could be because I have the Samsung hooked up to the DVI and cable via component.

[bdraw]

The color looks much better and there is less aliasing.
It could be because I have the Samsung hooked up to the DVI and cable via component.

Also most TV's have different video settings for each input.
So if you tweeked one you have to tweek them all.

[passedpawn]

The color looks much better and there is less aliasing.
It could be because I have the Samsung hooked up to the DVI and cable via component.
In this case, the cable box is doing the digital-to-analog (D/A) conversion for cable, and the TV is doing the D/A conversion for OTA. It is possible that the TV is much better at this. It is also possible that the analog signals on the component cables are being affected on the trip to the TV.

Geez, I'm jealous. I wish I had a DVI input on my TV. That is the ideal situation, where the signal remains digital until the last possible link in the video stream.

Bdraw has a good point... maybe by playing with the color and hue settings of your TV you can get the different inputs to match.

[JBtampa]

Stereophile's Guide to Home Theatre has a blip in the current issue on this subject. I don't have it in front of me right now, but they said something that implies cable operaters are allowed to "groom" or some such word to allow less data on high-def signals. They don't like the practice and imply a cable signal just lacks abilities as compared to broadcast.

[bdraw]

Stereophile's Guide to Home Theatre has a blip in the current issue on this subject. I don't have it in front of me right now, but they said something that implies cable operaters are allowed to "groom" or some such word to allow less data on high-def signals. They don't like the practice and imply a cable signal just lacks abilities as compared to broadcast.

I have read similiar articles.
But it varies from cable co to cable co.

I don't belive that BHN does this.
I think we get the same stream.
We won't know for sure till April, when they will give us STB's withe Firewire.
Then we can record the same show from both OTA and BHN.
Once we have the file recorded on the computer we can compare them and see if they have the same Bitrate.

[passedpawn]

Stereophile's Guide to Home Theatre has a blip in the current issue on this subject. I don't have it in front of me right now, but they said something that implies cable operaters are allowed to "groom" or some such word to allow less data on high-def signals. They don't like the practice and imply a cable signal just lacks abilities as compared to broadcast.

I have read similiar articles.
But it varies from cable co to cable co.

I don't belive that BHN does this.
I think we get the same stream.
We won't know for sure till April, when they will give us STB's withe Firewire.
Then we can record the same show from both OTA and BHN.
Once we have the file recorded on the computer we can compare them and see if they have the same Bitrate.
What box will this be? My wife really wants to start getting the HBO sitcoms so I may be getting a box at some point.

[bdraw]

What box will this be? My wife really wants to start getting the HBO sitcoms so I may be getting a box at some point.

It will probably be a Pace HD550 w/ firewire.

If you look at Pace's website you will see that it is available with firewire.

The cable companies have agreed to make Firewire enabled STB's available apon request as of April 1st 2004.
Also they did specify that they would work as well! ;)

By the end of 2005 all new cable STB's will have it.

[StevenA]

I was at the Tampa Home Show this past weekend talked with a salesman at a booth where they were selling a package deal (RCA 50-inch DLP set with DirectTV and an optional OTA antenna). The salesman told me that BHN broadcasts all of their HDTV signals at 720p resolution. If I wanted to get 1080i I would have to go with satellite or OTA. I'm not sure how reliable this information is, however, considering that it came from someone who was trying to make a sale.

I don't currently have HDTV, but I'm planning to get into it in the near future. Doing as much research and learning as I can for now.

[bdraw]

I was at the Tampa Home Show this past weekend talked with a salesman at a booth where they were selling a package deal (RCA 50-inch DLP set with DirectTV and an optional OTA antenna). The salesman told me that BHN broadcasts all of their HDTV signals at 720p resolution. If I wanted to get 1080i I would have to go with satellite or OTA. I'm not sure how reliable this information is, however, considering that it came from someone who was trying to make a sale.

I don't currently have HDTV, but I'm planning to get into it in the near future. Doing as much research and learning as I can for now.

That is a Lie.

Anyone can take their Pace box and set it to pass through to verify that this information is not true.

Not to mention it doesn't matter anyway.

No one has the right equipment to do a true comparison of 720p vs 1080i.

Anyone that says either one is any better than the other is speaking of hearsay, and not of fact.

Untill there is a day when someone has a TV that can natively display 720 and 1080 it is almost impossible to say which is best.

[CANDY76MAN]

just theoreticly speaking I would think that 720p would look slightly more solid but not quite as sharp while 1080i is the opposite....I want 1080p :twisted:

[passedpawn]

just theoreticly speaking I would think that 720p would look slightly more solid but not quite as sharp while 1080i is the opposite....I want 1080p :twisted:

This discussion has gone on and on and on and on at AVS. The consensus (and common sense conclusion) is that that 720p is better for video with fast camera movement, like sports, and 1080i is better for more static images. That said, the consensus is that there isn't enough action in any sport (perhaps excepting NASCAR) to make 720p look better. The detail is just not there.

Note: those with 720p native displays (i.e., many plasma owners) will vehemently disagree with the statements above. Maybe they are correct for their display.

[passedpawn]

No one has the right equipment to do a true comparison of 720p vs 1080i.

Anyone that says either one is any better than the other is speaking of hearsay, and not of fact.

Untill there is a day when someone has a TV that can natively display 720 and 1080 it is almost impossible to say which is best.

I would think that many have this setup. If the STB can output Firewire, then most PCs could archive it, and play it back. With a standard LCD panel, the two images (720p vs. 1080i) would be easily compared. Especially if the video card could drive two displays at the same time.

I don't have any experience with the HTPC stuff, but the dots seem to be connectable. Anyone out there confirm my hypothesis.

[bdraw]

I would think that many have this setup. If the STB can output Firewire, then most PCs could archive it, and play it back. With a standard LCD panel, the two images (720p vs. 1080i) would be easily compared. Especially if the video card could drive two displays at the same time.

I don't have any experience with the HTPC stuff, but the dots seem to be connectable. Anyone out there confirm my hypothesis.

All LCD's that are currently availible are native 1280x720. They scale everything internally to 720p.
So if you feed it a 1080i signal it just scales it to 720p.
There are some LCD's that are supposed to do 1080p in the future, but you run into the oposite problem, everything will be scaled to 1080p.

Also there is no content that is avalible in both 720p and 1080i format.

To do a true comparison you would have to have both clips filmed at the same time under the same circumstances.

I don't ever see this happening, at least anytime soon.

[passedpawn]

I would think that many have this setup. If the STB can output Firewire, then most PCs could archive it, and play it back. With a standard LCD panel, the two images (720p vs. 1080i) would be easily compared. Especially if the video card could drive two displays at the same time.

I don't have any experience with the HTPC stuff, but the dots seem to be connectable. Anyone out there confirm my hypothesis.

All LCD's that are currently availible are native 1280x720. They scale everything internally to 720p.
So if you feed it a 1080i signal it just scales it to 720p.
There are some LCD's that are supposed to do 1080p in the future, but you run into the oposite problem, everything will be scaled to 1080p.

Also there is no content that is avalible in both 720p and 1080i format.

To do a true comparison you would have to have both clips filmed at the same time under the same circumstances.

I don't ever see this happening, at least anytime soon.

What, you mean everyone doesn't have one of these (http://www.apple.com/displays/acd23/). 1920x1200. Oh, Santa....

[passedpawn]

What, you mean everyone doesn't have one of these (http://www.apple.com/displays/acd23/). 1920x1200. Oh, Santa....

BTW, I saw one of these at CompUSA, last wkend, in Clearwater. Remarkable.

[CANDY76MAN]

why are you guys stuck on lcd? a decent regular crt computer monitor can easily do both resolutions if you have a fast enough cpu and videocard....you can go here http://www.microsoft.com/windows/windowsmedia/content_provider/film/ContentShowcase.aspx and get the same clips in 720p and 1080p...they don't have any 1080i clips unfortunatly and I'm not sure where you would get them.

don't forget to set your monitor res to 1920x1440 when viewing them...especially the 1080p ones.

the bottom of that link links to another movie besides t2 that comes with a second disk with a wm9 hd version of the movie.

[bubblehd647]

LOL!

720p vs. 1080i

The "Taste great! Less filling!" battle of the HDTV community. :D

[bdraw]

why are you guys stuck on lcd? a decent regular crt computer monitor can easily do both resolutions if you have a fast enough cpu and videocard....you can go here http://www.microsoft.com/windows/windowsmedia/content_provider/film/ContentShowcase.aspx and get the same clips in 720p and 1080p...they don't have any 1080i clips unfortunatly and I'm not sure where you would get them.

don't forget to set your monitor res to 1920x1440 when viewing them...especially the 1080p ones.

the bottom of that link links to another movie besides t2 that comes with a second disk with a wm9 hd version of the movie.

Ok there is no 55" CRT that I know of.

It also depends on what you are testing.

What is better source material?
What is a better display?

As we all know you can display 720p at 1080i or visa versa.

Also there is no 1080i just 1080p on that site.
So any comparison wouldn't be between 1080i, I think everyone would agree that 1080p is better than 720p.

[bdraw]

LOL!

720p vs. 1080i

The "Taste great! Less filling!" battle of the HDTV community. :D

Actually I am not argueing for either.

I am simply stating that no one knowes which is best, because there is no consumer test environment to compare.

[gmclaughlin]

Sorry, I just noticed this thread was here -- I've only been reading the BHN talk section.

First, the home show guy is (looking for a polite term here...) wrong. BHN passes the signal to the settop in the format it's presented to us. Then, depending on what box you have, the output resolution is determined. If you have a S/A 3100HD, everything coming out the component outputs is 1080i. If you have a Pace 550HD, then you have the choice to specify output resolution at 1080i, 720p, 480p, or 480i, or just let whatever resolution the broadcaster adopted pass through.

Regarding the Stereophile Guild to Home Theater article, it's full of misleading assertions. First, every cable company, and indeed, almost every cable operation in the country is different -- you can't paint them all with the same brush. Heck, I think the differences in BHN in Central Florida vs. Tampa alone would prove my point.

Secondly, does BHN remove bits from the HD stream -- yes. Because the 8VSB modulation scheme is intended for OTA broadcasts, its designed to deliver an intact signal despite the "challenging" environmental conditions the signal must traverse. QAM modulation, conversely, is designed to travel in the protected path a Hybrid Fiber Coax cable plant provides. Therefore, the robust error correction data the 8vsb signal sends along with the video/audio is unnecessary, and even more so, unused at the receiving end. The short version is that we don't need to send a full 19.4mbs to deliver the exact same signal -- the bits that are the signal come through untouched.

We've been accused of compressing signals time and time again. All I can say is that it isn't true. We don't own any compression equipment. Heck the other day I was trying to get some locally produced video encoded to put it on our iControl platform, and I had to send the tape to inDemand to get them to pitch it back via satellite.

I finally convinced the Orlando High Definition Society folks that we don't compress by giving them a tour of our headend. We can't do it, because we don't have the equipment to do so. Period.

The final thing the Stereophile guide complained about was a device that performs "rateshaping". While there are companies trying to sell these to us, we haven't bought any.

Finally, while I can't comment on our retransmission agreements with broadcasters specifically, I will say that nearly all retransmission agreements contractually forbid the cable operator from altering the primary video signal.

Oh, and I don't like subchannels either.

Hope this clarifies things.

[FTBoomerIII]

Sure does Greg. Thanks for clearing this up.