Hi, I want to buy a TV larger than 60 inches since my viewing distance is about 13 feet but I'm not sure if it's worth investing in 1080P TV. I watch some HD TV but mostly regular DVD and will not upgrade to a HD DVD anytime soon (at least until this on going battle settles down). But I'm wondering if DVD picture will look grainy if I get 720P TV with that large screen size. I do have an upcovertable DVD player but not sure how much this will help. Anyone has experience in watching regualr DVD from 60 inch 1080p vs 720p side by side? Thanks in advance.

How long do you plan to keep the display? Blu-ray has the support of every studio but Universal (http://www.highdefdigest.com/), which is likely to get on board next year. There's no reason to invest money in DVDs at this point, imo. However, even if you aren't ready to purchase a Blu-ray or HD-DVD player and get your disks from Netflix, you'll be ready to make the jump later if you have a 1080p TV.

Moreover, don't you watch high-definition from cable or satellite? NBC and CBS already broadcast movies and episodic content like Heroes and CSI in 1080p24, plus sports in 1080i60.

At 13' feet, you should give serious consideration to a 70" 1080p display. DVD will still look very good, high-definition from cable/satellite will look stunning, and good Blu-ray releases (http://www.highdefdigest.com/) -- when you are ready to make the jump -- will blow your mind.

If you are on a budget, look at the 71" DLP from Samsung and the 70" LCOS (D-ILA) from JVC. Members have found both under $3500. If price isn't a concern, add the Sony 70XBR2 to your list as well. If you can't accomodate the ~20" depth of current Samsung or JVC 70" displays, JVC has a new slim 65" model with a depth of 12" coming in March.

http://comcal.wboc.com/img/resvsdist.jpg

NBC and CBS already broadcast movies and episodic content like Heroes and CSI in 1080p24, plus sports in 1080i60.

1080p?? I think you meant 1080i.


Anyway, to the original poster. 1080p isn't that big a deal, no tv right now does 1080p properly anyway(can't do 1:1 conversion due to 24 not fitting evenly into 60hz which all tvs are right now). Most tvs convert 1080i to 1080p so tvs with 1080p inputs only help PS3 games look better. A tv that can display(upconvert) 1080p resolution is still nice.

13' isn't too far for a 60" hdtv by any means. I have a 62" and sit 15' away and it is BIG!! My wife would kill me if it was even 1" larger. At 15' a 70" would be way too big for me. I love a big screen, but when you get the set in your home, you will see what I mean. Unless you have a dedicated home theater room in which case the TV overpowering the room isn't a problem. I have VERY good eyesight, and if I sit any closer, all I see is more imperfection, not more detail. I see perfect detail at 15' with a 62".

I wouldn't count out blu-ray or Hd-dvd, they are coming on STRONG and I believe they will start replacing your average joes sd-dvd players in the next year or two. Once they hit the $300 and less price range(soon) anyone with an hdtv would be nuts not to upgrade, the picture is AWESOME!! The media will also come down to regular dvd prices in the next couple years also.

1080p?? I think you meant 1080i.

He probably meant that the original 1080p24 frames can be fully recaptured from 1080i30 fields, as most deinterlacers correctly implement reverse 3-2 pulldown.


Anyway, to the original poster. 1080p isn't that big a deal, no tv right now does 1080p properly anyway(can't do 1:1 conversion due to 24 not fitting evenly into 60hz which all tvs are right now).

The fact that the 24Hz frames have to be repeated with a 2:3 cadence is not a big deal. That's the way most of us have been watching DVDs for years and no one is complaining.

He probably meant that the original 1080p24 frames can be fully recaptured from 1080i30 fields, as most deinterlacers correctly implement reverse 3-2 pulldown.



The fact that the 24Hz frames have to be repeated with a 2:3 cadence is not a big deal. That's the way most of us have been watching DVDs for years and no one is complaining.
I would think the 1080p24 image is translated to 1080p30 (via telecine), and then interlaced to 1080i60, and broadcasted. The TV then deinterlaces the 1080i60 to produce 1080p30, and then doubles each frame and produces the 60 hertz video.

SO, I don't think the TV is doing any inverse telecine (to change back to a 24fps rate). The only reason you would wantto do that is if your TV supports a variable refresh rate (72hz for example) like some high end models do.

For the sake of argument, there are two interesting things to take note of here:

1) Judder is introduced when a 24fps movie is converted to a multiple of 30fps.
2) Artifacts are introduced when the video is interlaced/deinterlaced.

So, the only way to get a 100% accurate reproduction of a movie filmed in 1080p24 is to get a blu-ray player that outputs raw 1080p24, and a TV that has a 72hz refresh rate. Then there is no telecine and no interlace/deinterlace step.

I'm sure it would be very hard to notice the difference though. But it *is* there.

That's why when someone tells you "1080p doesn't matter", that is really an ambiguous statement. Like most other things in life, it is not completely cut and dry like people make it out to be. The correct statements regarding 1080p versus 1080i are:

1) A 1080p24 movie can be delivered in 1080i60 with minimal degradation, so minimal that the average person will never see a difference. But judder and deinterlacing artifacts are introduced

2) 1080p60 (true 60 frames per second) video fill look more fluid than 1080p30 (1080i60) video. Its the same argumnt ESPN uses for xmittng sports in 720p60 insetad of 1080i60. You'll see a sligth difference in games and fast motion video.

Also, fr any 1080p bashers out there, the biggest advantage of a 1080p TV that can be realized today (not the distantfuture likesome purport) is that it will display 1080 content without having to scale the image. A non 1080p TV has a native resolution of 1366x720, which is less than half the pixels of a 1080p TV. Contrary to what people say, you *can* see a difference between 1366x720 and1920x1080. For some video, the difference is slight, however, it depends upon the material. I cansee a difference between Good Morning America on ABC (720p) and Today n NBC (1080i) - the Today show is sharper.

I sometims think the dissing of 1080p was originated by Microsoft propaganda, or Xbox zealots. XBox 360 originally didn't support 1080p, and they tried to convince everyone it didn't matter. Okay, my last point is a little wacky :)

1) Judder is introduced when a 24fps movie is converted to a multiple of 30fps.
2) Artifacts are introduced when the video is interlaced/deinterlaced.

There should be no deinterlacing artifacts, because there's no motion from field to field that has to be interpolated with something that was shot on film at 24 fps. Each field is an exact half of the frame (not offset by motion that occured in 1/60th of a second like with an interlaced source), so they combine perfectly.

I would think the 1080p24 image is translated to 1080p30 (via telecine), and then interlaced to 1080i60, and broadcasted. The TV then deinterlaces the 1080i60 to produce 1080p30, and then doubles each frame and produces the 60 hertz video.

SO, I don't think the TV is doing any inverse telecine (to change back to a 24fps rate). The only reason you would wantto do that is if your TV supports a variable refresh rate (72hz for example) like some high end models do.This is not accurate. I was posting fact, not speculation. From the video processor like the VP50, you get 1080p24 output for the channels and programs I gave as examples. There is a very practical reason why it is done this way -- transmission of 1080p24 flagged as 1080i60 requires significantly less bandwidth than 1080p30 flagged as 1080i60.

There is no effective difference between the 1080i60 output on most CBS and NBC programs and the 1080i60 output from a Blu-ray or HD-DVD player, beyond the higher compression.

2) Artifacts are introduced when the video is interlaced/deinterlaced.

So, the only way to get a 100% accurate reproduction of a movie filmed in 1080p24 is to get a blu-ray player that outputs raw 1080p24, and a TV that has a 72hz refresh rate. Then there is no telecine and no interlace/deinterlace step.As eric notes above, this is not accurate. There are no artifacts added for de-interlace of film-sourced (24p) content, provided the display or video processor can lock onto the 3/2 cadence.

What you say is certainly true of 1080i60 video.

For those new to how this all works, Silicon Optix has a nice introductory video tutorial right here (http://www.hqv.com/technology/index1/cadence_detection).

2) 1080p60 (true 60 frames per second) video fill look more fluid than 1080p30 (1080i60) video. Its the same argumnt ESPN uses for xmittng sports in 720p60 insetad of 1080i60. You'll see a sligth difference in games and fast motion video.Be careful not to confuse 1080p30 with 1080i60. They are two very different things. No sports today are acquired in 1080p30. They are acquired in 1080i60. Rather than 30 frames acquired per second, each at 1/30s, 60 fields are acquired separately at different points of time (1/60s). In order to create a 60p image for display, the display's video circuitry must interpolate to create the missing information for these fields. How well the video processing in the display is able to interpolate the fields to create each 1080p frame plays a large role in the quality that ultimately makes it to your screen.

HQV has an introductory s video tutorial on that topic as well, here (http://www.hqv.com/technology/index1/deinterlacing).

1080p?? I think you meant 1080i.

Anyway, to the original poster. 1080p isn't that big a deal, no tv right now does 1080p properly anyway(can't do 1:1 conversion due to 24 not fitting evenly into 60hz which all tvs are right now).No, I meant 1080p. And many 2006 displays do 1080p "properly" -- yes, today's 60Hz displays introduce cadence-based judder, but that has absolutely nothing to do with display of full 1080p resolution. I suggest you review the link I posted above.

13' isn't too far for a 60" hdtv by any means. I have a 62" and sit 15' away and it is BIG!! My wife would kill me if it was even 1" larger. At 15' a 70" would be way too big for me. I love a big screen, but when you get the set in your home, you will see what I mean. Unless you have a dedicated home theater room in which case the TV overpowering the room isn't a problem. I have VERY good eyesight, and if I sit any closer, all I see is more imperfection, not more detail. I see perfect detail at 15' with a 62".I've got to question the credibility of this post.

As you can see from the resolution chart posted above, one is not able to resolve anywhere remotely close to 1080p resolution from a 62" screen at a seating distance of 15'. You aren't even able to resolve full 720p resolution. With 20/20 vision, you would only be able to resolve ~600p. There is plenty more detail and resolution to be seen from the same screen at a shorter viewing distance, or the a larger screen from the same distance.

Any imperfections this particular individual is seeing at closer distances are inherent to his TV and its video processing or the source.

This is not accurate. I was posting fact, not speculation. From the video processor like the VP50, you get 1080p24 output for the channels and programs I gave as examples. There is a very practical reason why it is done this way -- transmission of 1080p24 flagged as 1080i60 requires significantly less bandwidth than 1080p30 flagged as 1080i60.

There is no effective difference between the 1080i60 output on most CBS and NBC programs and the 1080i60 output from a Blu-ray or HD-DVD player, beyond the higher compression.

As eric notes above, this is not accurate. There are no artifacts added for de-interlace of film-sourced (24p) content, provided the display or video processor can lock onto the 3/2 cadence.

What you say is certainly true of 1080i60 video.

For those new to how this all works, Silicon Optix has a nice introductory video tutorial right here (http://www.hqv.com/technology/index1/cadence_detection).

Be careful not to confuse 1080p30 with 1080i60. They are two very different things. No sports today are acquired in 1080p30. They are acquired in 1080i60. Rather than 30 frames acquired per second, each at 1/30s, 60 fields are acquired separately at different points of time (1/60s). In order to create a 60p image for display, the display's video circuitry must interpolate to create the missing information for these fields. How well the video processing in the display is able to interpolate the fields to create each 1080p frame plays a large role in the quality that ultimately makes it to your screen.

HQV has an introductory s video tutorial on that topic as well, here (http://www.hqv.com/technology/index1/deinterlacing).
That's interesting. I stand corrected, and I suck :) I need to make sure I indicate that I'm speculating in my posts.

In order to get into that format, the stream is first taken through the 2:3 pulldown process to produce 30 frames per second.The first video tutorial (http://www.hqv.com/technology/index1/cadence_detection) deals with film (24p) sources. For a program like CSI on CBS,you have:

Frame1, Field1
Frame1, Field2
Frame2, Field1
Frame2, Field2
Frame2, Field1
Frame3, Field1
Frame3, Field2
Frame4, Field1
Frame4, Field2
Frame4, Field1

Repeated over and over. If the display's processing did not detect this 3/2 repeat cadence, and just handled fields in sequential pairs, the fields would be mismatched, creating artifacts.

Virtually all displays released in the past 2-3 years will correctly detect the 3/2 cadence for 480p24 content delivered in 480i60 format. That's why many find they get a better picture when they enable 480i pass-through on their set-top box. Their display does 3/2 detection for 480i sources but the STB -- when set to output at 480p or 720p -- does not.

Unfortunately, many displays are not yet able to do the same for 1080i60 signals. If you see a difference between the 1080i60 and 1080p60 output from your Blu-ray or HD-DVD player, it is because your display does not correctly detect the 3/2 cadence. As there are no STBs or DVRs with 1080p output, a display's ability to detect the film cadence is very important to the quality you get on movies and episodic content shown on CBS, NBC, HBO, Starz, etc.

Silicon Optix is about to release a HD-DVD (followed by a Blu-ray) test disk which will make it easier for consumers to confirm this capability, or lack thereof, on their displays. Anandtech previewed this test disk (http://www.anandtech.com/video/showdoc.aspx?i=2923) earlier today. Based on his tests, it looks like a HTPC is not the way to go if you care about 1080p output quality.

No, I meant 1080p

So you are saying that NBC and CBS are transmitting in 1080p?? I have never heard of this, its either 1080i or 720p from any and everything I have seen.

So you are saying that NBC and CBS are transmitting in 1080p?? I have never heard of this, its either 1080i or 720p from any and everything I have seen.Yes, it is native 1080p24 on movies and episodic content (like CSI) in a 1080i60 package, just like you get from a HD-DVD or Blu-ray player set to output 1080i. All the 1080p information is there, but your display has to detect the 3/2 cadence in order to fully reconstruct the original 1080p image.

Sports and other live broadcasts (like news and award shows) by NBC and CBS are still native 1080i60. The networks do not do any live video broadcasts in 1080p.

Thanks for the replies. This is more technical information than my humble brain can juggle but very useful neverthless. One of the questions that still remain is -- how will the 60 inch 720P TV play regular DVD at 13 feet away? Is 1080P noticeable better or I really can't tell? I have a tight budget and I don't need to future proof it as much if I'll be satisfied with what I am watching which is mostly regular dvds. And based on the viewing chart it doesn't seem that I will be fully realizing the potentials of 1080P at 13 feet away. So the bottom line is I am willing to shell out extra dough for 1080P IF the DVD (primary) and 1080i HD (secondary) picture is better with 1080P at 13 feet away. Unfortunetely, I couldn't test this at a local CC or Best Buy because no HD TVs are hooked up a regular DVD anymore... Thanks again for helping this rookie.

The first video tutorial (http://www.hqv.com/technology/index1/cadence_detection) deals with film (24p) sources. For a program like CSI on CBS,you have:

Frame1, Field1
Frame1, Field2
Frame2, Field1
Frame2, Field2
Frame2, Field1
Frame3, Field1
Frame3, Field2
Frame4, Field1
Frame4, Field2
Frame4, Field1

Repeated over and over. If the display's processing did not detect this 3/2 repeat cadence, and just handled fields in sequential pairs, the fields would be mismatched, creating artifacts.

Virtually all displays released in the past 2-3 years will correctly detect the 3/2 cadence for 480p24 content delivered in 480i60 format. That's why many find they get a better picture when they enable 480i pass-through on their set-top box. Their display does 3/2 detection for 480i sources but the STB -- when set to output at 480p or 720p -- does not.

Unfortunately, many displays are not yet able to do the same for 1080i60 signals. If you see a difference between the 1080i60 and 1080p60 output from your Blu-ray or HD-DVD player, it is because your display does not correctly detect the 3/2 cadence. As there are no STBs or DVRs with 1080p output, a display's ability to detect the film cadence is very important to the quality you get on movies and episodic content shown on CBS, NBC, HBO, Starz, etc.

Silicon Optix is about to release a HD-DVD (followed by a Blu-ray) test disk which will make it easier for consumers to confirm this capability, or lack thereof, on their displays. Anandtech previewed this test disk (http://www.anandtech.com/video/showdoc.aspx?i=2923) earlier today. Based on his tests, it looks like a HTPC is not the way to go if you care about 1080p output quality.
Wow, I've really learned a lot today. Thanks for these posts.

So, to recontruct and display 1 second of a 24fps movie transmitted at 480i60/1080i60 on a display with a 60hertz refresh, the TV has to:

1 - Identify 3:2 sequence, and reconstruct the original 48 interlaced fields
2 - Deinterlace the 48 fields
3 - Perform telecine on the 24 frames to produce 30 frames
4 - Output frame1, frame1, frame2, frame2, .. frame30, frame30

Is that correct?

This might be off the original topic of the thread, but I'm just curious about the theory behind all this. In particular, in the process of conditioning a 480p24/1080p24 movie for 480i60/1080i60 broadcast, why is the interlacing step done first and then the telecine? If the telecine was done first and then the interlacing, then the monitor wouldn't have to do reverse pulldown. It could just deinterlace the signal, recover the 30 frames per second, and then double each frame for 60hz output. Is it done this way to somehow reduce bandwidth? If you do it the latter way, you are creating a 1080p30 stream instead of 1 1080p24 stream, thus more bandwidth. Is that why?

Thanks

To answer the question in the original post based on the info I've read here, for a regular DVD it will not matter if its 720p or 1080p and depending on the viewing distance and size of the tv it may not matter for HDDVD or BluRay.

Thanks for the replies. This is more technical information than my humble brain can juggle but very useful neverthless. One of the questions that still remain is -- how will the 60 inch 720P TV play regular DVD at 13 feet away?Most important to DVD quality is the video processing in the TV and the other display performance metrics, such as contrast ratio, color decoder accuracy, etc.

Generally, when you pay extra for 1080p models you don't simply get higher resolution, but improved video processing and contrast ratio as well. That isn't always the case, but I believe it is true when comparing many 720p vs 1080p DLPs.

I'm assuming at some point, possibly next year, you will budget for a Blu-ray player, since that standard is moving quickly to replace DVD within the big-screen home. If you haven't followed the high-def disk developments, be sure to bookmark HighDefDigest.com (http://www.highdefdigest.com/).

IMO, buy a 1080p TV if you're going above 55".

If you do it the latter way, you are creating a 1080p30 stream instead of 1 1080p24 stream, thus more bandwidth. Is that why?Yes.

MPEG-2 @ 1080p24 fits nicely within the limitations of ATSC transmission, but 1080p30 really pushes the limits, which is why we don't see it used. I'm not aware of any broadcast or cable programming that uses 1080p30, outside of demos / tests.

1 - Identify 3:2 sequence, and reconstruct the original 48 interlaced fields
2 - Deinterlace the 48 fields
3 - Perform telecine on the 24 frames to produce 30 frames
4 - Output frame1, frame1, frame2, frame2, .. frame30, frame30


1) You should probably call that "extracting" or "selecting" the interlaced fields. The TV is getting 60 interlaced fields per second and can throw away the 12 redundant fields.

3 and 4) Telecine is the process of scanning film to video. I'd just call outputting 24fps @ 60fps 2:3 pulldown. It goes from 24fps->60fps, there is no intermediate step at 30fps.

Here is how I described the process in another thread, along with a link to another article with pictures that perhaps makes this easier to understand. BTW, this question gets asked all the time, and some clueless noob with no understanding of 24fps film sources always claims you can't reconstruct a progressive source from 1080i60, and they're always wrong.

Consider what happens at three points in time, 0T, 1T, and 2T, where T is 1/24th of a second. For the 24Hz progressive original:

0T: Frame 0
1T: Frame 1
2T: Frame 2

For the 60i interlaced signal
0T: Odd field of Frame 0
.4T: Even field of Frame 0
.8T: Odd field of Frame 0
1.2T: Even field of Frame 1
1.6T: Odd field of Frame 1
2T: Even field of Frame 2
etc.

You can see that for every frame, all of the information is there (both odd and even fields) for the deinterlacer to completely reassemble the original 24Hz progressive frames. Putting the frames back together correctly (odd and even fields of frame 1 together, odd and even fields of frame 2 together) rather than mixing fields from adjacent frames is what a good deinterlacer does. This is called reverse 3:2 pulldown because it reverses the 3:2 pulldown done when creating the interlaced fields.

I might have gotten odd and even reversed but it doesn't matter. For a better explanation of this with graphics, see http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm