FOX - 720p, the highest standard in High Definition, true?

[dory]

Hi, this is a two part question but I've done some research on HDTV and learned a lot but i'm still confused on a couple of things. Mainly the whole 420p, 420i, 720p, 1080i, etc, etc. I know from what i've read the P and I just stand for progressive or Interlace. And apparently 720p and 1080i are the best resolutions to view HD in. Now my first question: Fox says for games like the World Series and football that their broadcasts are in 720p, the world's finest High Definition. But from other sites i've read they say that 1080i can be superior to 720p.

Is what Fox broadcasts in 720p really better then 1080i?

My next question is are HD broadcasts EITHER 720p OR 1080i? Meaning, are they one OR the other and NOT both? The reason I ask that is because certain channels like Discovery or Nature channels look MUCH nicer and sharper then sports broadcasts so i'm wondering if those broadcasts might be 1080i while the Sports broadcasts are 720p?

I have a Comcast digital cable box and there are three options I can set, one is I believe 420p or 480p, and the other two are 720p and 1080i. The default setting is 1080i, but should I change my cable box to 720p for a broadcast like Fox's with their sports in 720p, or should I just leave my box at 1080i?

Thanks in advance for any input and/or answers to these questions.

[gshelley61]

1280x720p and 1920x1080i are the only two HD resolutions. Because 720p is a progressive scan (not interlaced) image, it is thought to be better for high action images, like sports. All 720 lines are displayed at the same time, reducing jagged edges, etc.

The 1080i signal is actually two interlaced fields with 540 lines that occur at slightly different times, thus causing a small amount of jaggies and stair stepping, especially in high motion segments. And don't let the 1920 horizontal pixel figure fool you. Due to limitations in the system that are too complex to go into here, the maximum perceived res is actually closer to 1400, even on a display capable of true 1920x1080 resolution.

Digital HD transmissions are actually MPEG2, so how well the source material is encoded and compressed for transmission has a huge effect on how good it looks.

Both standards can look excellent, either way.

The cable companies, broadcasters and satellite providers transmit in one or the other standard. Standard def material is upconverted to an HD signal, but that does not improve the picture. In the case of your cable box, set it at whatever output looks best on your HDTV. LCD and DLP displays are progressive scan, so usually 720p looks best on those. CRT based HDTV's may look better with a 1080i signal, but it depends on the specific unit.

[dory]

gshelley, thank you for the explanation and information regarding the resolutions, etc. I think i've pretty much got it. The only thing i'm still unclear of is the whole Cable broadcasting thing. So you are saying that cable companies either broadcast in 720p OR 1080i, not both, right?

If that's the case, then wouldn't it affect the way a broadcast that is the other resolution? Let's say the Fox 720p resolution for example. If Fox is broadcasting in 720p and my cable company broadcasts in 1080i, wouldn't the picture quality suffer because it's not a true 720p? I don't know if i'm making any sense but I'm just a little confused on why the companies broadcast in either one or the other when certain programming is specifically 720p OR 1080i, you know?

[gshelley61]

gshelley, thank you for the explanation and information regarding the resolutions, etc. I think i've pretty much got it. The only thing i'm still unclear of is the whole Cable broadcasting thing. So you are saying that cable companies either broadcast in 720p OR 1080i, not both, right?

If that's the case, then wouldn't it affect the way a broadcast that is the other resolution? Let's say the Fox 720p resolution for example. If Fox is broadcasting in 720p and my cable company broadcasts in 1080i, wouldn't the picture quality suffer because it's not a true 720p? I don't know if i'm making any sense but I'm just a little confused on why the companies broadcast in either one or the other when certain programming is specifically 720p OR 1080i, you know?

The upconversion/dowconversion scalers used to convert 720p to 1080i (or vice versa) are very sophisticated and work very well. It is difficult to perceive a difference or any artifacts caused by scaling.

[dory]

The upconversion/dowconversion scalers used to convert 720p to 1080i (or vice versa) are very sophisticated and work very well. It is difficult to perceive a difference or any artifacts caused by scaling.

ahh, so there's something called "upconversation/downconverssion Scalers" which convert one to the other, interesting, you sound like a pro, thanks for all the information, it is appreciated and i've learned a lot.


I guess I do have one other little question i'm figuring you could probably answer as well so i'll ask you. Why is it that certain HD channels have a much better picture then others? Comcast only offers like 8 HD channels in my area and out of those 5 of those are local channels which are almost never in HD anyway, so there's really only 3 channels which are HD and out of those three, 2 of them show programming like Discovery channel where the HD is MUCH clearer then say CBS Or Fox's sports broadcasts, is there any reason for this?

Another real amazing oddity I noticed was when I happened to flip through and see "SportsCenter." I'm not a big sports fan but I happened to notice when sportscenter was showing highlights a couple of weeks ago for all the NFL games, that some of the highlights weren't as crisp and sharp as others. What I mean is that they showed all the games and the highlights were all in HD, so for example Cleveland and Philadelphia was one set of highlights, Kansas City and Atlanta were another set. Those two looked good but not nearly as great as the Indianapolis Colts vs. the Jacksonville Jaguars highlights. I was laying down while I flipped through and saw the highlights and as they went from game to game I watched but as soon as they showed the Colts/Jaguars highlights it was so amazingly crisp and sharp I actually sat up. I couldn't believe how clear the picture was. The only thing I could logically think of was that the Colts played that game at home which is in a "DOME" where no weather or wind is a factor so I figured the feed from the cameras may of been much better then alot of those outdoor games where Wind and rain, etc. is a factor.

Does that make any sense at all? lol, I don't know I would just think HD is HD and all the programming would look as crystal clear as that Colts Jaguars game, I was really surprised though that there was so much of a difference from that game to the others. What do you think could case that?

[BJ_M]

just a clarification - 720p and 1080i are the only wildly used CONSUMER high definition standard- as you said ..

but in fact - we use several other HD formats, there are 28 standard SMPTE HD formats and another 4 or 6 being added ...

there are 6 currently ATSC HD formats.

There also is oddball HD formats used by some devices -- for example I use 1440p a lot ..

[leebo]

Digital HD transmissions are actually MPEG2, so how well the source material is encoded and compressed for transmission has a huge effect on how good it looks.

True. I was in Costco today and they had their HDTV's displaying the HD Outdoor channel. The bitrate was so low it looked worse than a typical DVD. I've seen what real HD can look like at NAB in Las Vegas. No comparison. But like it was mentioned, the Costco displays could be the result of the cable or satellite provider they use.

[gshelley61]

The upconversion/dowconversion scalers used to convert 720p to 1080i (or vice versa) are very sophisticated and work very well. It is difficult to perceive a difference or any artifacts caused by scaling.

ahh, so there's something called "upconversation/downconverssion Scalers" which convert one to the other, interesting, you sound like a pro, thanks for all the information, it is appreciated and i've learned a lot.


I guess I do have one other little question i'm figuring you could probably answer as well so i'll ask you. Why is it that certain HD channels have a much better picture then others? Comcast only offers like 8 HD channels in my area and out of those 5 of those are local channels which are almost never in HD anyway, so there's really only 3 channels which are HD and out of those three, 2 of them show programming like Discovery channel where the HD is MUCH clearer then say CBS Or Fox's sports broadcasts, is there any reason for this?

Another real amazing oddity I noticed was when I happened to flip through and see "SportsCenter." I'm not a big sports fan but I happened to notice when sportscenter was showing highlights a couple of weeks ago for all the NFL games, that some of the highlights weren't as crisp and sharp as others. What I mean is that they showed all the games and the highlights were all in HD, so for example Cleveland and Philadelphia was one set of highlights, Kansas City and Atlanta were another set. Those two looked good but not nearly as great as the Indianapolis Colts vs. the Jacksonville Jaguars highlights. I was laying down while I flipped through and saw the highlights and as they went from game to game I watched but as soon as they showed the Colts/Jaguars highlights it was so amazingly crisp and sharp I actually sat up. I couldn't believe how clear the picture was. The only thing I could logically think of was that the Colts played that game at home which is in a "DOME" where no weather or wind is a factor so I figured the feed from the cameras may of been much better then alot of those outdoor games where Wind and rain, etc. is a factor.

Does that make any sense at all? lol, I don't know I would just think HD is HD and all the programming would look as crystal clear as that Colts Jaguars game, I was really surprised though that there was so much of a difference from that game to the others. What do you think could case that?

Perhaps some of the highlights were not recorded in HD. I don't know if every game is produced in HD yet.

[dory]

Perhaps some of the highlights were not recorded in HD. I don't know if every game is produced in HD yet.

Hello, thx again for your response. Well, that's the thing, actually all those games were either Fox or CBS games that ESPN was showing highlights of and I was watching ESPNHD which was showing those highlights in "HD." I mean they looked better then analog for sure but they just weren't super crisp like the highlights of the Colts game which was played in a dome, but I'm not sure if that would affect anything. What do you think?

Just for fun I looked up and saw the Colts play this Monday night at home vs. Minnesota. So it will be interesting to see the quality of the transmission of that game vs. other Monday Night games i've happened to see and see if there's a noticeable difference from the outdoor games vs. this one.