View Full Version : 1080p resolution question
gregftlaud
04-16-08, 01:54 PM
OK I just got a new Panny HD Plasma TV today the Viera model. It's model TH-50PZ80U. It's 1080p. I dont use the native setting on my HR20 b/c changing channels takes to long. Should I set my HR20 to 1080 or have both 720 and 1080 enabled and switch to the appropriate resolution depending on what channel I am watching? I've read before in these forums you should just set your HR20 to your TV's native resolution. If I do that will it handle 720p signals ok? I used to have a panny with a 720p resolutions and had the HR20 set to 720 of course.
Thanks for any feedback.
jodyguercio
04-16-08, 02:08 PM
OK I just got a new Panny HD Plasma TV today the Viera model. It's model TH-50PZ80U. It's 1080p. I dont use the native setting on my HR20 b/c changing channels takes to long. Should I set my HR20 to 1080 or have both 720 and 1080 enabled and switch to the appropriate resolution depending on what channel I am watching? I've read before in these forums you should just set your HR20 to your TV's native resolution. If I do that will it handle 720p signals ok? I used to have a panny with a 720p resolutions and had the HR20 set to 720 of course.
Thanks for any feedback.
Ive got the older 58" Veira model (TH-58PX60U) and I just leave the HR20 set to 1080i and I am happy with that. IMO, you should set the resolution to what you can live with.
OK I just got a new Panny HD Plasma TV today the Viera model. It's model TH-50PZ80U. It's 1080p. I dont use the native setting on my HR20 b/c changing channels takes to long. Should I set my HR20 to 1080 or have both 720 and 1080 enabled and switch to the appropriate resolution depending on what channel I am watching? I've read before in these forums you should just set your HR20 to your TV's native resolution. If I do that will it handle 720p signals ok? I used to have a panny with a 720p resolutions and had the HR20 set to 720 of course.
Thanks for any feedback.
As far as I know if you set it at the higest allowable resolution, it will dumb down to the lower usable resolution. Mine is set to 1080i. And when I cycle through the HR20 resolutions, it blows up on the low 480i setting. But it automatically dumbs down to everything else.
Your 1080p is really only usable with Bluray and HD-DVD as they do 1080p. The highest format currently being broadcast is 1080i. I suspect if you set your TV to 1080p it will take whatever resolution the HR2x and DVD, Bluray or HD DVD and game console sends to it.
gregftlaud
04-16-08, 05:17 PM
Doesnt CBS and NBC and DTV broadcast in 1080p? Or is that "i". i'm stupid. Anyways my tv is 1920x1080 so then u think I should just set it to 1080i?
Doesnt CBS and NBC and DTV broadcast in 1080p?1080i.
For HD on your display, I'd set the HR to Native on and make sure both 720p and 1080i are checked. Your display will line-double the 1080i broadcasts to get to 1080p, or multiply your 720p broadcasts by 1.5. Both should provide very clean "upconversions" to your display's native resolution.
/steve
gregftlaud
04-16-08, 05:29 PM
Ew I hate having native on b/c when u change between channels with different resolutions it takes forever. I think i'll just stick with 1080i and let my TV handle it. Thanks for your feedback guys!
Thaedron
04-16-08, 05:45 PM
1080i.
For HD on your display, I'd set the HR to Native on and make sure both 720p and 1080i are checked. Your display will line-double the 1080i broadcasts to get to 1080p, or multiply your 720p broadcasts by 1.5. Both should provide very clean "upconversions" to your display's native resolution.
/steve
I didn't think line doubling was necessary, I thought the 1080i signal was captured and both frames "re-assembled" into a 1080p image.
I didn't think line doubling was necessary, I thought the 1080i signal was captured and both frames "re-assembled" into a 1080p image.You could be 100% right! I just assumed line-doubling was going on, and when you assume... :) /steve
rudeney
04-16-08, 07:57 PM
I have a similar TV (Panasonic th-50PZ77U) that is 1080p. I also don’t like the delay when switching channels in “native” mode, so I have my HR20 set to use 1080i only. I have tried native to see if the TV does a better job of scaling than the HR20, and honestly, I cannot tell a difference. Many people claim that the TV’s circuitry does a better job of scaling, but I don’t know if that’s true or not. I have yet to see any scientific evidence one way or the other.
Also, I have a 42” Panasonic plasma that’s a 720p set. I put the two TV’s side-by-side and tried various test of resolutions and cabling and I just can’t tell a difference. The 50” 1080p has a better picture, but it’s 3 years newer and uses a 1920x1080 screen instead of the 1366x768 of the 42”. As for deciding to use 1080i vs. 720p on a 1080p capable set, remember that a while a 1080i signal does have to be de-interlace, the horizontal resolution isn’t affected, so you are getting 1920 pixels across instead of just 1280 in 720p. While there are some inherit “scientific” factors in interlaced signals no being as crisp as progressive, I honestly doubt that the typical human can see them with their eyes.
I didn't think line doubling was necessary, I thought the 1080i signal was captured and both frames "re-assembled" into a 1080p image.That's a better explanation than "line doubling", which technically doesn't happen. And yes, you are exactly correct.
While 1080p is in the family of POSSIBLE broadcast or transmission protocols, it is not now and likely never will be practical, and is not now and likely never will be used, other than for Blu-Ray DVDs.
It really helps to understand this if you make the distinction between transmission protocols and display protocols. 1080i is a common transmission protocol (and 1080p could be, it just won't be). But 1080p is indeed the dominant display protocol, while 1080i is all but extinct as a display protocol (except on a few older CRT HD displays -- try finding one of those anywhere but in a museum in a few years).
The reason has nothing to do with any potential superiority over 1080i, but with the simple fact that flat-panel displays are LIMITED TO PROGRESSIVE display modes. They rescale 720p, but they deinterlace 1080i and display it as 1080p (without the minimal advantages of true 1080p content, unless done at 24fps, which is exceptionally rare).
1080i is considered interlaced content, and has two fields per frame. Each field has 540 lines that are stretched from top to bottom of the visible raster. For each frame, all lines comprising the entire first field are sent first, directly after which all of the lines comprising the entire second field are sent.
The display captures the first field (of 540 lines) and holds it in a buffer, then captures the second field (of 540 lines), and then stitches them all back together like a Vegas blackjack dealer shuffles the two halves of a deck of cards together, in order; line 1 from field 1, line 1 from field 2, line 2 from field 1, line 2 from field 2, etc. and so displays all 1080 lines in serial fashion, or one line after another, from top to bottom in one pass, which is exactly how "progressive" display technology reinterlaces interlaced content.
A question that comes up is "what rez should I set my STB at?" There are two practical choices.
If you set the rez to "native", it will essentially pass thorough all resolutions and leave any reinterlace or rescaling tasks up to the display. This has a very-minimal advantage IF ANY, seeing as how modern rescaling and reinterlacing can be done equally well in either the set or the STB. It also has the disadvantage of slow recovery times when changing channels.
If instead you set the rez of the STB to match that of the native rez of the display, then those tasks happen in the STB, which is basically of no disadvantage. That is then probably the recommended setting.
There are two exceptions:
If your set is older than about 2005 and therefore may not reinterlace well (the technology to do it right only existed for 3 manufacturers by 2004, and for all by 2005), it might make sense to set the STB to 720p, as this will force interlacing tasks into the STB, which if a Tivo or HR2x, will do a better job. This has the slight disadvantage of potentially reducing some resolution of 1080i images, but probably not noticeably, and may be a trade-off well worth doing.
If the set has a native rez of 1366x768, the set will always rescale, and reinterlacing could be done in either the display or STB. Since you can't ever match 1080 or 720 to 768 without rescaling, double rescaling is inevitable for about half the content (unless you use the "native" setting). The good news is it probably won't hurt the PQ. In this case use the 1080 setting on the STB (assuming you want to avoid the long refresh times of "native"), unless the set also has interlace issues as described above.
cartrivision
04-16-08, 09:22 PM
I didn't think line doubling was necessary, I thought the 1080i signal was captured and both frames "re-assembled" into a 1080p image.
That's correct, except that it's two "fields" that are reassembled into one frame. A field contains every other line of the frame, and every other field contains the lines that the adjacent fields are missing.
If instead you set the rez of the STB to match that of the native rez of the display, then those tasks happen in the STB, which is basically of no disadvantage. That is then probably the recommended setting.
Are you sure about that? A 720p transmission being displayed on a 1080p display will then have to be interlaced and scaled to 1080i, transmitted, then deinterlaced to 1080p by the display.
If you left the STB at native, then 720p would be transmitted at 720p, and ONLY scaled to 1080p, without the interlacing/deinterlacing steps.
cartrivision
04-17-08, 11:52 AM
Are you sure about that? A 720p transmission being displayed on a 1080p display will then have to be interlaced and scaled to 1080i, transmitted, then deinterlaced to 1080p by the display.
If you left the STB at native, then 720p would be transmitted at 720p, and ONLY scaled to 1080p, without the interlacing/deinterlacing steps.
You are correct. That way instead of 3 transforms on the signal (720->1080->interlaced->deinterlaced) you only have 1 (720->1080), and you avoid interlacing altogether along with the artifacts that it can add.
Most people would probably never notice any interlace artifacts and almost nothing is broadcast in 720p anyway, so it's not really a big deal. I'm pretty picky about how my picture looks, and I have my HR20 set to always convert everything to 1080i because when left in native mode, I don’t like the momentary confusion on the screen as the TV figures out which resolution to switch to, and what little 720p source I happen to watch looks very good to me even with the unnecessary interlace to deinterlace conversion steps.
Bergthold
04-17-08, 01:09 PM
If the set has a native rez of 1366x768, the set will always rescale, and reinterlacing could be done in either the display or STB. Since you can't ever match 1080 or 720 to 768 without rescaling, double rescaling is inevitable for about half the content (unless you use the "native" setting). The good news is it probably won't hurt the PQ. In this case use the 1080 setting on the STB (assuming you want to avoid the long refresh times of "native"), unless the set also has interlace issues as described above.
I have a Samsung Plasma with the 1366x768 rez. So are you saying I should leave it at 720 or 1080? I can't really see any difference and have been using it in 1080 mode.
This discussion brings me to ask a simple question:
What resolution are recordings made at?
I understand the arguments from those in the native camp versus those in the single resolution camp, when viewing live tv, but if we talk about recorded playback, what resolution is being saved the box and then broadcast to the TV?
cartrivision
04-17-08, 01:51 PM
This discussion brings me to ask a simple question:
What resolution are recordings made at?
I understand the arguments from those in the native camp versus those in the single resolution camp, when viewing live tv, but if we talk about recorded playback, what resolution is being saved the box and then broadcast to the TV?
Everything is recorded in it's native resolution that DirecTV broadcasts it in. The raw digital stream is just save to the disk without changing it.
Stuart Sweet
04-17-08, 02:46 PM
That's a better explanation than "line doubling", which technically doesn't happen. And yes, you are exactly correct.
(...)
In this case use the 1080 setting on the STB (assuming you want to avoid the long refresh times of "native"), unless the set also has interlace issues as described above.
TomCat, that was an excellent post on the subject. Well put!
jodyguercio
04-17-08, 02:47 PM
I have a Samsung Plasma with the 1366x768 rez. So are you saying I should leave it at 720 or 1080? I can't really see any difference and have been using it in 1080 mode.
You answered your own question. Youve tried both resolutions and you cant see a difference so just leave it the way you are most comfortable with. ;)
Most people would probably never notice any interlace artifacts and almost nothing is broadcast in 720p anyway, so it's not really a big deal.
Except sports. :) They're almost always in 720p as the movement is just smoother. Other than that, I'd agree, the momentary confusion and delay just isn't worth the possible pq improvement. But I want my football as clean as possible.
And as far as the delay goes, the hr21 seem to have gotten MUCH better as of late. Even with resolution changes, channel changes are now down around 3-5 seconds, instead of 6-10, ugh.
cartrivision
04-17-08, 04:38 PM
Except sports. :) They're almost always in 720p as the movement is just smoother. Other than that, I'd agree, the momentary confusion and delay just isn't worth the possible pq improvement. But I want my football as clean as possible.
And as far as the delay goes, the hr21 seem to have gotten MUCH better as of late. Even with resolution changes, channel changes are now down around 3-5 seconds, instead of 6-10, ugh.
I think that ABC, ESPN, and Fox are the only major networks who broadcast in 720p. All the other major network and cable stations broadcast in 1080i, and they don't change it for sports programming.
I think that ABC, ESPN, and Fox are the only major networks who broadcast in 720p. All the other major network and cable stations broadcast in 1080i, and they don't change it for sports programming.
Exactly. And those are the channels that normally show acc college football. Sorry I didn't specify.
Ew I hate having native on b/c when u change between channels with different resolutions it takes forever. I think i'll just stick with 1080i and let my TV handle it. Thanks for your feedback guys!
I tried Native ON when I first got my HR20 in Sept of 06. The whole thing bombed on an early software version and I have not tried it again since. No need really as far as I can tell. What exactly would Native On get me?
Never mind... I read TOMCAT's excellant post!
I didn't think line doubling was necessary, I thought the 1080i signal was captured and both frames "re-assembled" into a 1080p image.
So you are saying it is different for 1080p as compared to 730p??? I thought progressive scan was drawing all 1080 lines in one sweep while interlaced was every other line. The resolution does not matter. Or better yet, I had no idea how progressive scan works!!!!!
Never mind... I read TOMCAT's excellant post!
Brian Hanasky
04-18-08, 09:46 AM
So you are saying it is different for 1080p as compared to 730p??? I thought progressive scan was drawing all 1080 lines in one sweep while interlaced was every other line. The resolution does not matter. Or better yet, I had no idea how progressive scan works!!!!!
Never mind... I read TOMCAT's excellant post!
Nice avatar!
Are you sure about that? A 720p transmission being displayed on a 1080p display will then have to be interlaced and scaled to 1080i, transmitted, then deinterlaced to 1080p by the display.
If you left the STB at native, then 720p would be transmitted at 720p, and ONLY scaled to 1080p, without the interlacing/deinterlacing steps.That is exactly true. Set the output to 1080i, and 1080i would be passed through as 1080i and reinterlaced in the display as 1080p. 720p would indeed be deinterlaced and rescaled in the STB, and reinterlaced in the display.
What I mean by "no disadvantage" is that deinterlace and reinterlace of something originally progressive and then ultimately progressive is a completely non-destructive process. There is no loss of PQ involved, no loss of resolution, and no addition of any interlace error. You can deinterlace and reinterlace an originally-progressive signal over and over all day long and it comes out the other end exactly as it went in.
Deinterlace and reinterlace are, in this specific example of 720p eventually being displayed at 1080p (disregarding the rescaling), exactly opposite processes, and chaining them together has the ultimate result identical to as if it never happened at all. Deinterlace involves storing each line in memory and clocking them out in a different order. Reinterlace does exactly the same thing in reverse. The signal itself and the temporal reference between each line, while disturbed for a bit in the middle of the process, is at the end restored precisely as it was originally. Non-destructively.
So to answer your question, yes, I am sure about that.
I have a Samsung Plasma with the 1366x768 rez. So are you saying I should leave it at 720 or 1080? I can't really see any difference and have been using it in 1080 mode.Half the answer is in the quote. The other half is in the paragraph originally above it.
If your TV is newer than 2005, use 1080i or native. If it is older, 720p might actually work a little better. If you can't see a difference, then it probably doesn't really matter. If you are on the borderline (or even if you are not) look closely at diagonal lines. If you see no difference, use 1080. If 720 looks smoother, that would be the one that I would suspect would be the best choice.
It's a tradeoff, and here's the specific: on a 768-rez set with poor interlace, you will ALWAYS see jaggy stairstepping on diagonal lines when set to 1080i, which you will not see when set to 720p. But the price is potential reduction of resolution of static images from 1080i sources, to 720p resolution. That may not be noticeable EXCEPT VERY RARELY on real raster-scan camera video for a number of reasons.
For example, a HDNet test pattern on a 768 set from a DVR set to 1080i will show a resolution of about 6.8 MHz, while the same TP set to 720 will show a resolution of about 6.0 MHz. You can definitely see it on the TP, but real video rarely if ever reaches that level of resolution. About the best example I can think of is the set on "Late Night with Conan O'Brien". Freeze a wide shot of this and change resolutions, and everything will look exactly as sharp, with one exception: there are little stars sewn into the backdrop curtain that seem just a bit more precise in 1080 than they do in 720.
Half the answer is in the quote. The other half is in the paragraph originally above it.
If your TV is newer than 2005, use 1080i or native. If it is older, 720p might actually work a little better. If you can't see a difference, then it probably doesn't really matter. If you are on the borderline (or even if you are not) look closely at diagonal lines. If you see no difference, use 1080. If 720 looks smoother, that would be the one that I would suspect would be the best choice.
It's a tradeoff, and here's the specific: on a 768-rez set with poor interlace, you will ALWAYS see jaggy stairstepping on diagonal lines when set to 1080i, which you will not see when set to 720p. But the price is potential reduction of resolution of static images from 1080i sources, to 720p resolution. That may not be noticeable EXCEPT VERY RARELY on real raster-scan camera video for a number of reasons.
For example, a HDNet test pattern on a 768 set from a DVR set to 1080i will show a resolution of about 6.8 MHz, while the same TP set to 720 will show a resolution of about 6.0 MHz. You can definitely see it on the TP, but real video rarely if ever reaches that level of resolution. About the best example I can think of is the set on "Late Night with Conan O'Brien". Freeze a wide shot of this and change resolutions, and everything will look exactly as sharp, with one exception: there are little stars sewn into the backdrop curtain that seem just a bit more precise in 1080 than they do in 720.
So I understand about 60% of what you guys are saying, but I ask you to please dumb this down for me a little here. If I make the decision that I don't like the extra time it takes for Native On and so I turn it Off, what box or boxes should be checked in the Resolution Tab? Should I check the 720p and 1080i? 1080 only? Also note that I never want to have to press the Format button, as it isn't even programmed into my universal remote. Here are my options:
_480i
_480p
_720p
_1080i
an answer to this, even I could understand. waiting for the input ? thanks
cartrivision
04-19-08, 07:02 PM
So I understand about 60% of what you guys are saying, but I ask you to please dumb this down for me a little here. If I make the decision that I don't like the extra time it takes for Native On and so I turn it Off, what box or boxes should be checked in the Resolution Tab? Should I check the 720p and 1080i? 1080 only? Also note that I never want to have to press the Format button, as it isn't even programmed into my universal remote. Here are my options:
_480i
_480p
_720p
_1080i
If you don't want native on and you don't plan to ever change resolutions manually, you can check all resolutions that your TV supports, and then use the format button to select the one output format you want to use (and always stay on).
Once you do that, all source formats will be converted to the format you chose. If you have a 720p TV, I advise selecting 720p output for everything, and if you have a 1080p TV, select 1080i. That will give you the full resolution of what your TV is capable of displaying at all times.
...If I make the decision that I don't like the extra time it takes for Native On and so I turn it Off, what box or boxes should be checked in the Resolution Tab?...While I don't have an exact answer for you here, I can make an educated guess that it won't really matter if the goal is to make the refresh time as short as possible. The ones you check are the ones then that are available from the remote button. The idea of unchecking some of them is that there may be some that are of no particular use in a particular situation, and they can be dialed out so you don't have to toggle through them. This has nothing to do with shortening the refresh time of the display, which is where the bulk of the delay comes from.
Much of the delay is in the refrersh process of the display itself, which is similar to a multisync computer monitor in how it works. When you pass the same resolution all of the time (let's say you set your STB to 1080i) the display sees that resolution all the time, and consequently does not ever have to readjust itself to handle a new format. So if you change channels, even from a 1080i station to a 720p station, the display sees 1080i continually, and does not mute the video and reconfigure for a new resolution. IOW, it does not contribute to the delay.
When you are in native mode, the display must reaquire the new resolution format when changing channels. To do that it mutes the video for a moment while that happens.
rudeney
04-19-08, 08:57 PM
If you don’t want to use native, then you should use the resolution that best matches that of your TV. If you have a 1080p set, then the pixel grid of your TV display 1920x1080. The HR2x output of 1080i will give the best picture on that set. Your TV will need to de-interlace the signal, but the HR2x will be supplying the most number of pixels and will exactly math the resolution of your TV. If you have a 720p/1080i set, then the pixel grid of our TV display is 1366x768, so 720p will likely give the best image. In reality, on a 1366x768 display, you will likely not be able to tell the difference between a 1080i and 720p signal from the HR2x.
If you don't want native on and you don't plan to ever change resolutions manually, you can check all resolutions that your TV supports, and then use the format button to select the one output format you want to use (and always stay on).
Once you do that, all source formats will be converted to the format you chose. If you have a 720p TV, I advise selecting 720p output for everything, and if you have a 1080p TV, select 1080i. That will give you the full resolution of what your TV is capable of displaying at all times.
Ahhh, so if I have native Off, and push the Format button until I get the highest resolution/format (on any channel) and then I never press Format again, I will always get the highest res/format (on all channels)? Am I understanding correctly? Thanks.
Yes you will, and yes you are.
The only caveat is that "highest" might not equate to "best", as I have posted above. If it still seems murky, you will probably be just fine matching to the native rez of your set. Or, just try them all, and see if you see a difference. If you do, use the one that works best. If you don't, well then you don't, and you also don't have anything to concern yourself about. You don't have to completely understand the science of how a piano is tuned to appreciate the music, after all.
vBulletin® v3.7.6, Copyright ©2000-2012, Jelsoft Enterprises Ltd.