No discernable difference between 1080i and 1080p?

[dkennedy]

Still no discernable difference between 1080i and 1080p?

November 13, 2006

By Darren Murph, HD Beat Magazine

Although HomeTheaterMag has already told us that there's no (discernable) difference between 1080i and 1080p, it's quite understandable to still be skeptical when television manufacturers are screaming otherwise and touting 1080p as the new "must have" feature.

In the latest battle between the two outputs, eagle-eyed testers at CNET compared the 1080p output from the Blu-ray version of the hot-selling M:I III film on five different displays.

With monitors sporting resolutions ranging from 1,024 x 768 to 1,366 x 768 to 1,920 x 1,080, the conclusions were unsurprisingly similar to various other studies.

Essentially, reviewers stated that in a vast majority of the scenes, the "level of detail was virtually identical" across the higher resolution sets, and that even the (relatively) low resolution Philips 42PF9631D plasma showed imagery "difficult to discern" from more elite monitors.

Overall, testers felt that native 1080p rendered "slightly more detail in near background images in scenes with long depths of field," but was otherwise not really "necessary," and recommended that prospective buyers save their cash for the time being rather than buying in (literally) to the 1080p hype right now.

[dkennedy]

The case against 1080p

November 8, 2006

By David Carnoy , Executive Editor CNet Reviews

I've written a couple of columns about 1080p in the last couple of years (in March and October of 2005, to be precise), but now that the term is being bandied about quite freely in the consumer press with the arrival of next-generation DVD, it seems only appropriate to revisit the topic as more folks consider spending that 20 percent premium or so to step up a 1080p HDTV this holiday season. In case you haven't heard, 1080p displays, with their 1,920x1,080-pixel native resolutions, are theoretically capable of delivering the smoothest, sharpest picture.

In the past, I've given a more complete rundown of the pros and cons of 1080p, what it is, and how it fits into the grander scheme of HD resolutions. Senior Editor David Katzmaier's "HDTV resolutions explained" is also an excellent resource for getting a handle on the whole 1080p vs. 1080i vs. 720p debate.


But for this column, I'm going to go real-world on you and step into our A/V lab, where Mr. Katzmaier and I have set up five flat-panel HDTVs with native resolutions ranging from 1,024x768 (the Philips 42PF9631D 42-inch plasma) to 1,366x768 (the Panasonic TH-50PH9UK 50-inch plasma) to 1,920x1,080 (the Westinghouse LVM-47w1 47-inch LCD, the Sharp LC-46D62U 46-inch LCD, and the JVC LT-40FN97 40-inch LCD). We've hooked up the Samsung BD-P1000 Blu-ray player running the latest firmware and are using a Gefen HDMI Distribution Amplifier to pump out images to all five TVs at the same time. Then we pop in Mission: Impossible III, one of the best-looking Blu-ray movies we've seen to date. Our mission: see what differences we can discern in the picture quality at various resolutions.

Test No. 1: Movie is output at 1080p
We used a Blu-ray player because, unlike the first-generation HD-DVD players, it's capable of outputting 1080p video natively. This doesn't mean that it's necessarily superior to an HD-DVD player, but we required 1080p output for this test. (The Sony PlayStation 3 offers native 1080p output, as does the Xbox 360--but because the latter's 1080p output is limited to component or VGA cables rather than HDMI, the list of compatible TVs is far smaller.) It's important to note that, while two of the 1080p TVs we used in our test--the Sharp and the Westinghouse--accepted a 1080p signal, a lot of 1080p TVs, such as the JVC as well as most HDTVs with lower resolution, do not. (More details on that apparent paradox here.)

Comments: On both of the TVs that were capable of accepting a 1080p source, the picture looked really good. We noticed differences in the sets' color and blacks, but the level of detail is virtually identical on both sets.

Test No. 2: Movie is output at 1080i
OK, this where the fun starts--let the comparisons rip. We skip from chapter to chapter, looking for shots in which we might be able to discern differences. In scenes with close-ups of Tom Cruise--and there are a lot of them--or Philip Seymour Hoffman (the villain), it's very hard to notice a difference in detail, even when you compare the relatively low-resolution Philips 42-inch plasma (1,024x768) to the 47-inch 1080p Westinghouse (1,920x1,080), which are sitting side by side. But in chapter 5, we hit on a decent piece of test material. Tom Cruise walks into a stylish home, and there, just behind him, is a wall made of what look like small, wooden bricks. Lo and behold, if you concentrate just on that wall and scan back and forth from TV to TV, replaying the scene dozens of times, you'll notice a slight difference between the Philips and the Westinghouse; the brick pattern as displayed on the Westinghouse has a cleaner look. The difference is harder to discern when you compare the Westinghouse to the 50-inch Pioneer.

Comments: The differences in picture sharpness are minor and hard to discern. The main benefit of 1,920x1,080 native resolution in this test is slightly more detail in near background images in scenes with long depths of field. Also, although a direct comparison was difficult because we had to switch back and forth between 1080p and 1080i output on the Samsung player, we couldn't discern any difference between those two resolutions on the Westinghouse.

Note: The Sharp had problems with the Blu-ray player's 1080i output. For some reason, it seemed to soften the vertical resolution, so we couldn't make a valid comparison. It did not have this problem with 1080i from a Toshiba HD-A1 HD-DVD player, however. It's also worth noting that we have conducted similar side-by-side tests using the HD-DVD player and experienced similar results.

Conclusions
While this isn't the most scientific test, both Katzmaier and I agreed that, after scanning through Mission: Impossible III for an hour, it would be very difficult--practically impossible--for the average consumer to tell the difference between a high-definition image displayed on a 1080p-capable TV and one with lower native resolution at the screen sizes mentioned above. At larger screen sizes, the differences might become somewhat more apparent, especially if you sit close to the screen.

Reviewers like Katzmaier, who look at dozens of TVs over the course of the year, can see some very minor differences in picture sharpness when you step up to 1080p. How 1080i vs. 1080p plays out with video games--three PS3 launch titles offer native 1080p support--is less clear, but in the little time I've spent with the PS3, the differences seem very subtle and are ultimately tied into how good graphically the game looks to begin with. For instance, I saw Activision's Marvel: Ultimate Alliance on a 1080p Sony display, and the game looked decent, but it's not graphically stunning to begin with, so it wasn't completely amazing. By comparison, Resistance: Fall of Man looked great--even though the resolution is "only" 720p native, the PS3 exclusive makes far better use of the system's graphical horsepower than the Marvel game, which was simultaneously developed for all home consoles.

Ultimately, we agree with the Imaging Science Foundation (ISF), a group that consults for home-theater manufacturers and trains professional video calibrators, when it says that the most important aspect of picture quality is contrast ratio, the second-most important is color saturation, and the third is color accuracy. Though resolution may be the most talked-about spec these days, it comes in fourth on the ISF list, and after you sit watching five TVs lined up side by side, you understand why. The fact is a relatively pristine high-def source such as Mission: Impossible III looks sharp on just about any HDTV, and your eye, when looking for differences, is drawn first to things like depth of detail in shadowy material (black levels) and the color of the actors' skin tone and how natural it looks.

So when buying a TV, the last thing you probably want to do is agonize over its native resolution. If you don't mind spending the extra dough for 1080p, go for it. But if it's stretching your budget, then take a pass, knowing it's not all that it's cracked up to be.

Can you see the difference between 1080i and 1080p?

[rfeirstein]

A valid test would require a native 1080p/60 source [none exist outside of a video lab at this time]. You would need to feed this to a set that actually accepts and displays a 1080p/60 display. But other that a lab grade tube display I don't know of any. All 1080p/60 microdisplays, projection or otherwise, are not truly progressive but a form of fill the frame flash display, something quite different then created at the source in the studeo.

You would then need an "identical" 1080i/60 source material [good luck finding the same source material produced in both formats]. This would need to be displayed on a ideal interlaced display. I only know of direct view tube displays sold by Sony at about $20,000 a pop that display all the horizontal resolution offered by that format.

Other then this you are really viewing different displays and lots of chip sets converting one scan rate/resolution into another. So many fudge factors it is impossible to judge what is causing what.

We do know that in the complex broadcast/dish/DVD/cable chain, lots of compression and format conversion takes place and that progressed formats are easier to compress and convert giving a practical advantage to 720p even if displayed as 1080i or 1080p/flashed on your home screen. What you are actually seeing is the difference between the cable box/Blue ray box 720p or 1080i or 480i or 480p converters or the converters in you current HDTV set. Most new 1080p sets do a good job and next years increased scan rate displays will likely do even a better job, especially with 24 fps sourced film material.

Richard.