720p 1080i 1080p ???

[WIwinger]

I am looking for a new HDTV. I live in Waukesha. I have an old standard def tv that is failing. I recently had U-Verse installed and decided that it was time to upgrade to HD.

I have been trying to figure out which tv to purchase based on finances and type of signal. I really don't know very much about the signals except that "P" is progressive (the whole screen scans at the same time), and "I" is Interlaced ( every other line scans). I looked on Cnet and it seemed like they preferred 720P over 1080I because the whole picture scanned at the same time making action seem smoother. Is this correct, or is 1080I a better picture? What about 1080P?

I called U-Verse and the lady said that they broadcast in 1080I. What happens if you get a 720P set? Is it better to get a tv that matches the 1080I signal?

Perhaps Gregg or other guru's could give me some advice.

Thanks,
Terry

[Gregg Lengling]

Pick the TV you like and can afford. Most sets can handle either input and the STB's can be set to your native resolution.

[WIwinger]

Thanks,

If price wasn't an issue, then what? Is it then better to go with a 1080I because U-Verse uses that? Also what are STB's?

Terry

[MarkK]

These are very basic questions, which you can get answered far more quickly (and accurately) with a search of the internet, especially www.avsforum.com

However, that said, I'll give you a couple of answers. The P means progressive scan, which is what all new digital sets do automatically. These sets all possess scalers, that convert whatever format the picture is in, to the televisions native format. So get a 768P TV, and it will display a 1080i signal just fine.

[Bebop]

Get the 1080p. There is no reason to get anything less.

[Tom Snyder]

STB = Set-top Box
(STB)(also: Decoder, Receiver, Tuner) A unit similar to today's cable boxes, which is capable of receiving and decoding DTV broadcasts. A DTV 'Certified' STB can receive all (18) ATSC DTV formats, (including HDTV) and provide a displayable picture.

From Milwaukee HDTV Glossary (http://www.milwaukeehdtv.org/glossary.html)

[hormy_83]

Thanks,

If price wasn't an issue, then what? Is it then better to go with a 1080I because U-Verse uses that? Also what are STB's?

Terry

If price isn't an issue go 1080p. If price is an issue get whatever one you like the best that fits your budget - either one (720p or 1080i) will do very good.

[Mikey]

This isn't a simple question.

Screen size, viewing distance, lighting, budget, current components (hd-stb, video games, receiver), future components (blur-ray or hd-dvd), what you watch...all come into play.

AVS or audioholics are great places to start your search. Have fun with it. I had alot of fun oding my research for over a year before I had made up my mind and budgeted out the cash to pay for it in full.

This can turn into a hobbie, and once it does, it can get real expensive real quick.

Enjoy!

[TPK]

I called U-Verse and the lady said that they broadcast in 1080I. What happens if you get a 720P set? Is it better to get a tv that matches the 1080I signal?


Im curious about that....

Does this mean that u-verse is re-encoding ALL channels (including ESPN) to 1080i, even though they receive the broadcast of some channels, including ESPN in a 720p format?? (I am making the assumption here that TV services receive channels like ESPN in a 720P format, and that most TV services (like TWC) will then push out the channel in its native format)

This would mean that U-verse would be interlacing and upscaling a 720p channel into 1080i...

If this is what they are doing, then that is really quite sad....

It also means that I should probably set my u-verse box to output to 1080i instead of 720p....

I guess I would like to know specifically what u-verse said (if you can remember)... I would hate to think that this is what they are doing...

How pathetic, to take a nice clean non-interlaced TV broadcast and ruin it by interlacing it (not to mention killing it with mpeg-4 re-encoding, but thats a rant for another day)...

[WIwinger]

The 1080i comment from U-Verse was from a Customer Service Rep. I don't know if that was what she was told to say, or there is an answer that is more complicated. I suspect the latter based upon your concern. I would be interested in hearing a really good explaniation of it all.

[picopir8]

Uverse does either 1080i or 720p. You configure the box to be the resolution you want, then all channels are up/down converted to that resolution.

Even though different stations broadcast at different resolutions, and most sets accept multiple resolutions, each set has only one native resolution. So its best to set your devices to send data to your TV using that resolution so your TV does not have to to the up/down conversion. Some satellite receivers and cable boxes allow users to enable multiple resolutions and some people mistakenly enable all resolutions because their TVs support all resolutions. However that gains nothing since it just pushes the up/down conversion to your TV. Most set top boxes can do the conversion much quicker and more efficiency when it decodes/demodulizes the signal. Also forcing the devices to communicate using one resolution eliminates the resynch that takes place when changing resolutions which causes pictures to flicker.

So if you set the uverse box to 1080i, yes it upconverts* 720p signals to 1080i. Conversely, if you set the box to 720p, it converts everything to 720p. But that is actually better than taking both and pushing the up/down conversion onto your TV.

* Disclaimer: Some people insist that 720p to 1080i is downconversion since only 540 lines are drawn on each pass of a 1080i signal. However, 1080 sets are 1920 pixels across where as 720p sets are only 1620 pixels across. 720x1620=921600, 540x1920=1036800. Since 1080i has a higher pixel count, it is a higher resolution.

[StarvingForHDTV]

* Disclaimer: Some people insist that 720p to 1080i is downconversion since only 540 lines are drawn on each pass of a 1080i signal. However, 1080 sets are 1920 pixels across where as 720p sets are only 1620 pixels across. 720x1620=921600, 540x1920=1036800. Since 1080i has a higher pixel count, it is a higher resolution.

720p is 1280 pixels across, not 1620.

[TPK]

Uverse does either 1080i or 720p. You configure the box to be the resolution you want, then all channels are up/down converted to that resolution.

Even though different stations broadcast at different resolutions, and most sets accept multiple resolutions, each set has only one native resolution. So its best to set your devices to send data to your TV using that resolution so your TV does not have to to the up/down conversion. Some satellite receivers and cable boxes allow users to enable multiple resolutions and some people mistakenly enable all resolutions because their TVs support all resolutions. However that gains nothing since it just pushes the up/down conversion to your TV. Most set top boxes can do the conversion much quicker and more efficiency when it decodes/demodulizes the signal. Also forcing the devices to communicate using one resolution eliminates the resynch that takes place when changing resolutions which causes pictures to flicker.

So if you set the uverse box to 1080i, yes it upconverts* 720p signals to 1080i. Conversely, if you set the box to 720p, it converts everything to 720p. But that is actually better than taking both and pushing the up/down conversion onto your TV.

* Disclaimer: Some people insist that 720p to 1080i is downconversion since only 540 lines are drawn on each pass of a 1080i signal. However, 1080 sets are 1920 pixels across where as 720p sets are only 1620 pixels across. 720x1620=921600, 540x1920=1036800. Since 1080i has a higher pixel count, it is a higher resolution.


Actually, the way I understand it, different networks deliver their HD broadcasts either in 1080i or 720p...

I know this is true at least for local broadcast television... ABC HD (12-1) and Fox HD (6-1) trasmit their broadcasts in 720p, while NBC (4-1) and CBS (58-1) transmit thier broadcats in 1080i...

If you tune into those channels with a HDTV equipeed with a tuner, and have an 'info' button on your TV which will tell you what type of broadcast you are watching, you can see that if you are tuned to 6-1 your TV wil tell you that its 720p.. If you are tuned to 4-1 it will tell you that its 1080i...

For these local channels, I imagine all TWC does is take the digital OTA broadcast and re-transmit them in the same format they recieve it in (as they should) with re-modulation (if thats the right word) to a carrier frequency and encryption thrown in.... The box can then recieve, decrypt, and output the broadcast to your TV in its native format....

I imagine this is also true with cable networks as well... ESPN and any type of sports-centric channels will most likely transmit their broadcasts in 720p... While HBO and movie-centric channels will most likely transmit their broadcasts in 1080i..

Again, all I imagine all TWC is doing is just re-brodcasting those channels exactly as they recieve them, then your box can receive these digital channels and display them exactly as they were broadcast....

Now since I don't work for the cable company and don't really understand how they receive and re-transmit their broadcasts, I don't know this is how they do it for sure... As far as I know, they might recieve ESPN in a 1080p non-compressed format via satellite, and then re-transmit the broadcast twice in both a 1080i and 720p format, and let your box decide which one it wants to tune into... However I highly doubt this is what they are doing.. The way I described it before seems simpler and makes more sense....

So, given these assumptions about how these channels are broadcast, I highly doubt that TWC re-encodes these channels (all of them) to either 1080i or 720p... Its much easier for them just to send those channels out exactly as they receive it (which is how it should be)... The 1080i mpeg-2broadcasts remain 1080i mpeg-2, and the 720p mpeg-2 broadcasts remain 720p mpeg-2... As opposed to U-verse (and I imagine now with satellite) which takes the digital broadcasts and re-encodes them to mpeg-4, and in the case of their SD channels actually truncate off the sides of the HD digital broadcasts (I still can't get over the fact that they are doing this and not causing an uproar from both the consumers and the networks, of course I personally don't care about it that much because I don't watch SD)...

So, if this is the case, I believe you are much better off (I feel) to let your TWC box output to both 1080i and 720p, especially if you have a TV with a native resolution of 1080p...

Otherwise, if you set it just to output 1080i, then the box will take your ESPN/Fox 720p native broadcast and up-convert it to 1080 resoluton and interlace it before sending it to your television, which wont do anything for you resolution-wise and effectively cut the frame rate of the sports event you are watching in half... If you set it to output just 720p, then the box will take your NBC/HBO 1080i native broadcast and down-convert it to 720 resolution and de-interlace it before sending it to your television, which will cut the resolution of the picture down... In this case de-interlacing has to happen eventually anyhow (for most HD televisions), but I would rather trust my TV to de-interlace the broadcast than have the cable box do it...

I don't see 1080i as a down-conversion from 720p... I see it instead as a higher resolution format with half the frame-rate... Either you get a full 720x1280 picture 60 times a second, or you get a full 1080x1920 picture 30 times a second (in two half-pieces, laced every-other line)... 1080p would be a full 1080x1920 picture 60 times a second, but broadcast teleivsion will probably never obtain that kind of resolution (too much bandwidth)... That type of resolution will be obtained with HD/Blu-ray DVD players and gaming consoles...

[oz]

Check deal sites like http://www.slickdeals.net and http://www.fatwallet.com daily. There have been LOTS of HD television and monitor deals lately - mainly on flat panel LCD's. You should be able to find something within your budget.

[picopir8]

720p is 1280 pixels across, not 1620.

Oops, your right. Note to self, double check math when posting late at night...

[picopir8]

So, if this is the case, I believe you are much better off (I feel) to let your TWC box output to both 1080i and 720p, especially if you have a TV with a native resolution of 1080p...


This is the only time (having a 1080p set) when it might be adventageous to have the upconversion take place in the TV and not in the cable box. However, switching channels will change protocol that the TV an cable box use to communicate and cause the picture to freeze/flicker in the process. If you have a 1080i set or 720p set, it will still be better to have the cable box do the conversion.

[TPK]

This is the only time (having a 1080p set) when it might be adventageous to have the upconversion take place in the TV and not in the cable box. However, switching channels will change protocol that the TV an cable box use to communicate and cause the picture to freeze/flicker in the process. If you have a 1080i set or 720p set, it will still be better to have the cable box do the conversion.

Ya... I have a DLP projection with a 720 native resolution (NR)... So really it didn't matter all that much for me... The only real advantage of setting the TWC cable box to output both resolutions as opposed to just 720p I think would have been that I trust my TV to do the de-interlacing of the 1080i broadcasts a bit more than I trust the TWC cable box to do it...

de-interlacing can be (should be) handled with some processing to remove those "interlacing artifacts" that can be introduced into a picture when it stitches the two half-frames together into one.. Doing this can lead to descrepencies in the picture due to the fact that adjacent lines are actually 1/30th of a second out-of-sync with each other... The common example used to illistrate the problem is to imagine a pitcher throwing a fast baseball from the side... Without a good de-interlacer you would notice a bunch of motion blur of the baseball because half of the ball (every other line) is slightly ahead of the other half....

I'm sure that TWC/Scientific Atlanta/etc doesnt put a whole lot of effort or money into a good de-interlacer in their boxes... It probably just combines the two half frames and is done with it... TV manufacturers care a little bit more about image quality and probably invest more in a good de-interlacer that watch out for motion-blur and compensate for it....

Another issue that has to be addressed is, of course, downscaling (from a 1080 picture to a 720 picture)... A good downscaler should know how to downscale and avoid those moiere (sp?) effects and to smooth out those jagged lines, etc... Again, I would put more faith into my TV to do the downscaling than the cable box...

For these reasons, even though I had a 720 NR set, I still set the TWC box to output both resolutions, even though I had to put up with some delay when switching from a 720p channel to a 1080i channel...

Even so, the quality difference between these 2 methods (letting your cable box or your TV de-interlace and downscale) is probably neglagable to barely noticable most of the time... So in reality, in the case where the TV has a 720 NR, most folks are probably better off setting the box to a 720p output to match their television....

However if you have a TV set with 1080 NR (and most HD TVs being sold today have 1080 NR) then I think you really might be missing out if you force your box to one resolution or the other.... Either your going to give up the higher resolution of a 1080 picture, or your going to give up the higher frame rate and progressive qualtiy of a 720 picture...

Im not sure what you mean by a "1080i" set, unless you are referring to CRTs or CRT projection type sets that may still project the image in an interlaced manner with the electron gun and may not really have a specific native resolution.. Or maybe you a referring to the fact that a lot of 1080 NR sets are unable to accept a 1080p signal via its inputs...

Interlace/progressive largely describes the type of broadcast, and not really the television set itself... Marketing will sometimes advertise a TV set as "1080p", but typically this means is that the TV has a 1080 NR and will accept a 1080p signal via its inputs...

Almost all HDTVs sold today (and in the past number of years) are either direct display flat panels (like LCD/Plasma) or micro display projections (like DLP/Lcos/LCD Projection/etc..).. All of these have a true native resolution, and will display the image as a seamless whole, which means that they have to de-interlace the picture before displaying it as a whole picture... Only sets that still use "scan lines" (the soon to be dead CRT) can get away with displaying the picture in an interlaced manner (electron gun scans the odd lines, goes to the top, and then scans the even lines, etc.)...

Even if a 1080 NR set would be unable to accept a 1080p signal via HDMI or component (can component even do 1080p?), it should still accept either a 1080i signal, de-interlace, and attempt to use the higher resoluton of the display to show all/most 1080 lines of resolution and display at 30fps; or it should accept a 720p signal, attempt to upscale the image to its 1080 native resolution and display at 60fps.. It doesn't make sense for a micro-display or a direct display to interlace a 720p signal internally...

Long and short of it is, I think if you have a 1080 NR set and a TWC cable box, your are much better off and getting the highest quality picture out of your TV by enabling both resolutions in your cable box...

If you have a 720 NR set and a TWC cable box, you are just somewhat better off and getting the highest quality picture out of your TV by enabling both resolutions in your cable box...

Either way, by enabling both resolutions, you are going to have to put up with some delay in your picture as your TV has to re-sync from one resolution to the other when switching between channels of different resolutions (much like how a computer monitor as it changes resolutions)...

My personal opinion is that I would rather attempt to get the best picture qualtiy possible, even if it means putting up with the re-sync when switching channels...

In reality almost all cable networks are 1080i anyways (only the sports channels use the 720p standard), so unless Im switching to/from ESPN (or Fox or ABC) from something else, the sync delay doesnt happen most of the time anyhow... "Channel surfing" isn't an issue for me either, since Ive stopped scanning up and down the dial with channel up/down a long time ago and use the guide exclusively now (which can be unbelievably painful on these u-verse boxes)..

Anyhow, that is my opinion...