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Old April 11th, 2008, 10:14 PM   #31
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LOL, I was wondering when someone was going to link to that thread!
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Old April 12th, 2008, 08:59 PM   #32
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Originally Posted by Ken Ross View Post
Not even close. 60i will be around for a very very long time.
But it looks like we are getting more and better options, don't we?

Couldn't it be, that we are still having so much 60i around, because it has been around for such a long time? Given infrastructure, comparable to a person's habit? So, even if there are were options around, the more economical prevailed (for the moment)?
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Old April 12th, 2008, 11:52 PM   #33
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Sean, check the link I provided in the HV30 thread. Apparently, this is straight from the horse's mouth. IMO, 1080/60I (actually, any interlaced format) should never have been approved by the ATSC committee; nor should it have been included in the BDA spec. Clearly, there were factors at work in these decisions that were not in the best interests of consumers or the advancement of technology. Oh well, it is what it is.
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Old April 13th, 2008, 08:17 AM   #34
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Sorry duplicate post...deleted.
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Old April 13th, 2008, 08:18 AM   #35
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Originally Posted by Aaron Courtney View Post
IMO, 1080/60I (actually, any interlaced format) should never have been approved by the ATSC committee; nor should it have been included in the BDA spec. Clearly, there were factors at work in these decisions that were not in the best interests of consumers or the advancement of technology. Oh well, it is what it is.
It's called 'bandwidth' or lack thereof. Broadcasters barely have enough bandwidth for high quality, high bitrate 1920X1080 @60i, so it's not reasonble to think they would have had anything close to what would have been necessary for 60p at the same resolution.

Look at how Directv, Dish, Fios etc. are struggling to add more HD @60i. So that was, I'm sure, a prime motivating factor.

For me personally, when it comes to acquisition, I do not like 24p or 30p due to poor motion handling relative to 60i. When my cam has this feature, I totally ignore it.
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Old April 14th, 2008, 02:50 PM   #36
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It's called 'bandwidth' or lack thereof. Broadcasters barely have enough bandwidth for high quality, high bitrate 1920X1080 @60i, so it's not reasonble to think they would have had anything close to what would have been necessary for 60p at the same resolution.


The problem is that on modern progressive displays, 60i doesn't give the same motion advantage as it used to on CRTs, because it must be delinterlaced to 30P, and it doesn't save any bandwidth over 30P

Because of this, I personally think 60i should eventually go away as CRTs go away. It is now a solution to a problem that doesn't really exist anymore. It should be replaced by 30P for normal usage, and for fast motion, by *true* 1080/60P, where 60 *full* frames per second are recorded, and can be displayed on a 60Hz monitor without reducing it to 30P via deinterlacing. Yes, it will take more bandwidth to do that, but on progressive displays, it's the only way to get 60Hz motion. While bandwidth is still a limited resource for broadcasting, with Blu Ray disks and camcorders, there isn't such an issue, although it would require a really fast processor.
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Old April 14th, 2008, 04:03 PM   #37
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The problem is that on modern progressive displays, 60i doesn't give the same motion advantage as it used to on CRTs, because it must be delinterlaced to 30P...
But given that most consumer-grade HDTVs have a 1080i input (presumably designed to take a 60 field per second input), what exactly do they do with that signal? For example, if the HDTV simply displayed each field twice for alternating odd/even lines, wouldn't that yield a visual result similar to an interlaced CRT?

In any case, I have edited 60i material which looks fine when played from a PS3 to a 1080p LCD, so whatever's being done to accomplish that is working. I like the smooth motion of 60i for the projects I do and see problems with some 30p and 24p footage from digital video cameras, so for general-purpose use 60i seems to have a place yet in the modern world.
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Old April 14th, 2008, 04:47 PM   #38
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Originally Posted by Dave Rosky View Post
The problem is that on modern progressive displays, 60i doesn't give the same motion advantage as it used to on CRTs, because it must be delinterlaced to 30P, and it doesn't save any bandwidth over 30P

Because of this, I personally think 60i should eventually go away as CRTs go away. It is now a solution to a problem that doesn't really exist anymore. It should be replaced by 30P for normal usage, and for fast motion, by *true* 1080/60P, where 60 *full* frames per second are recorded, and can be displayed on a 60Hz monitor without reducing it to 30P via deinterlacing. Yes, it will take more bandwidth to do that, but on progressive displays, it's the only way to get 60Hz motion. While bandwidth is still a limited resource for broadcasting, with Blu Ray disks and camcorders, there isn't such an issue, although it would require a really fast processor.
I don't think the public would tolerate 30p video Dave. The stutter is just too much of an issue...it sure is for me. It's why I don't bother with it.

I just don't see much of an issue with 60i at all on a high quality fixed pixel display. Now if you're talking about 60p, that's a different story. But good luck seeing that for a long long time in broadcast.
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Old April 14th, 2008, 05:23 PM   #39
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I'll go ahead and add some more fuel to this fire. I am in complete agreement with Dave. Interlacing, as a format, was established to overcome some technical hurdles that no longer exist if you really get down to it. I don't think there's anyone who really believes interlacing is superior to progressive shooting - hey, go out and take half of a still photo, wait 1/60 sec and then take the second half, and then try your best to combine them while smearing the interframe movement to get rid of all the motion artifacts. This is exactly what is happening with today's progressive displays. Obviously, this is not how interlaced televisions of yesteryear functioned - although, as the MIT expert noted in that link I provided, interlacing never really worked as advertised even with interlaced displays.

For everyone who complains about 30P video, I highly doubt you have actually watched 30P under the ideal conditions - BD player ignores 60i flags, realizes it's dealing with no interframe motion (progressive), so it weaves the two fields together to recreate the original progressively acquired frame, frame doubles to hit 60Hz, and then outputs to 1080p/60 display.

To my knowledge, there's only ONE BD player on the market - Sammy BDP1200 - that will do this correctly, although it has a host of other problems not related to video processing, so it's not a popular model among videophiles.

I have no idea what would happen if someone broadcast a 1080/30P signal and your 60Hz PDP/LCD tried to tune it in. But, it's in the ATSC spec, although I suppose that doesn't guarantee perfect compatibility.
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Old April 14th, 2008, 05:36 PM   #40
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But given that most consumer-grade HDTVs have a 1080i input (presumably designed to take a 60 field per second input), what exactly do they do with that signal? For example, if the HDTV simply displayed each field twice for alternating odd/even lines, wouldn't that yield a visual result similar to an interlaced CRT?
I don't believe progressive displays work that way because they can't display fields, only frames. So the display receives the first field, stores it in its buffer, receives the second field comprising frame 1, de-interlaces the two fields, in an attempt to progressively display the original frame (won't ever work if the frame came from interlaced video, can work if frame came from progressive video), then, I presume, it flashes frame 1 twice to match 30 fps to 60 Hz refresh rate.

So it's a "fake" 60fps, just like 3:3 pulldown on a Pioneer Kuro (72 Hz) is a "fake" 72fps from 24fps film material. In the case of the 60i video, you're simply repeating the same frame twice. I would bet that if people who complain about 30P video would watch frame doubled 30P on a 1080/60P, not one "motion" complaint would be raised. Conversely, if everyone had to watch 60i at 30fps on progressive displays (exactly what is happening with 30P video improperly decoded by BD+progressive display chain), there would be an uproar.
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Old April 14th, 2008, 05:43 PM   #41
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Conversely, if everyone had to watch 60i at 30fps on progressive displays...there would be an uproar.
But I'm doing exactly this and it looks fine to me, so the de-interlacing must be working reasonably well. Conversely, I regularly see footage on the news now with obvious motion-judder issues, so I wonder what's going on there...?
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Old April 14th, 2008, 05:54 PM   #42
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For everyone who complains about 30P video, I highly doubt you have actually watched 30P under the ideal conditions - BD player ignores 60i flags, realizes it's dealing with no interframe motion (progressive), so it weaves the two fields together to recreate the original progressively acquired frame, frame doubles to hit 60Hz, and then outputs to 1080p/60 display.

To my knowledge, there's only ONE BD player on the market - Sammy BDP1200 - that will do this correctly, although it has a host of other problems not related to video processing, so it's not a popular model among videophiles.
If true, then perhaps that's the problem. Good luck with only the Sammy 1200 being able to do that. I wouldn't touch the Samsungs with a 10' pole, but that's me. But I sure as heck haven't seen smooth motion handling with 30p from a consumer camcorder hooked up directly to the display. Additionally, I don't like the idea of having to hassle with software to improve things I get right away with 60i. Each to his own I guess.

I also wonder at times if people have seen high quality 60i broadcasts on a high quality 1080p plasma. On my 1080p 60" Pioneer Elite Kuro, motion is beautiful and interlaced artifacts are minimum and most times simply absent. This is a far cry from the interlaced artifacts we used to get under our old NTSC system. In fact, I much prefer 60i and its higher resolution to 720p broadcasts. Yes, I'll take 60p over all of them, but we're a long way from there.
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Old April 14th, 2008, 05:54 PM   #43
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Kevin, yes, the de-interlacing of the progressive displays is "good enough" - no doubt, it's probably as good as it could ever get if you buy the best video processing tech today. BUT, it will never be "perfect", as in shooting progressively for display on progressive televisions. Now, you're talking native language to the display - no complicated conversions required, which result in nominal to significant reductions in original resolution.

It's like buying an E85 vehicle or whatever they're called and instead of using that fuel, installing some sort of converter to allow you to keep filling up with reg. gasoline which screws up your fuel economy. It doesn't make any sense, LOL!
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Old April 14th, 2008, 06:03 PM   #44
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This is a far cry from the interlaced artifacts we used to get under our old NTSC system.
I am going to have to disagree with you here, Ken. IMO, there were no artifacts present because we were watching interlaced footage on interlaced televisions! There was no de-interlacing. Everything was speaking the same language.

I am in the fortunate position to own both an interlaced HDTV and a couple progressive HDTV's (PDP & LCD). If I watch SD DVD's (480i material) on the progressive sets, I can spot interlaced artifacts - easy to see the jaggies on the edges of circular objects as the camera is panning across them. If I watch that same DVD on the Sony interlaced CRT, presto, jaggies are gone! Sure, the image is "softer" but I'd rather have that than distracting artifacts.
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Old April 14th, 2008, 06:26 PM   #45
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I don't believe progressive displays work that way because they can't display fields, only frames. So the display receives the first field, stores it in its buffer, receives the second field comprising frame 1, de-interlaces the two fields, in an attempt to progressively display the original frame (won't ever work if the frame came from interlaced video, can work if frame came from progressive video), then, I presume, it flashes frame 1 twice to match 30 fps to 60 Hz refresh rate.

So it's a "fake" 60fps, just like 3:3 pulldown on a Pioneer Kuro (72 Hz) is a "fake" 72fps from 24fps film material. In the case of the 60i video, you're simply repeating the same frame twice. I would bet that if people who complain about 30P video would watch frame doubled 30P on a 1080/60P, not one "motion" complaint would be raised. Conversely, if everyone had to watch 60i at 30fps on progressive displays (exactly what is happening with 30P video improperly decoded by BD+progressive display chain), there would be an uproar.
I think this post really hits the nail on the head. What many people don't realize, and what I didn't realize either until after a lot of internet searching, is that modern, non-CRT TV's are strictly progressive and don't display separate fields separately in time. They buffer the fields and then deinterlace them. When you watch 60i on an LCD TV, you are actually watching 30P in 2:2 pulldown because the TV has deinterlaced your 60i and then plays the deinterlaced frames twice in a row. As far as I have seen, all non-CRT TV's work that way, at least all common ones. Because the two fields are not displayed separately, you would loose the effect of 60 fps motion even though the display's refresh rate is 60Hz.

I don't yet have an LCD or plasma TV (I am in the market for one), but the above fact makes me wonder why a lot of people say that 30P video looks bad. It must indeed look bad, or people wouldn't say that; but the only thing I can think of is that possibly a lot of TVs somehow don't handle a true 30P signal proplerly and that causes display problems, because other than some sort of problem like that, 30P and delinterlaced 60i should look quite similar.

Historically, interlace was introduced mainly to solve the trade-off between flicker and phosphor persistence in CRT tubes. Phosphors can be made short or long persistence. Long persistence phosphors don't flicker at low refresh rates, but they tend to smear motion. OTOH, a phosphor with a persistence short enough to display 30 fps without smearing would have too much flicker in bright ambient light. So, the compromise trade-off was to interlace the video to increase the effective display rate to 60 Hz, eliminating flickering without taking any extra bandwidth than 30 fps. Now that displays store frames and fields in RAM, this persistence issue goes away, even for plasma TVs (which still use phosphors, but in a different manner than CRTs).
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