720 vs. 1080 debate

[Thomas Smet]

thanks for the input guys.

I agree with Barry...

With the new Panasoinc camera it isn't really an issue anymore because we can shoot whatever we need to.

[Ken Hodson]

Ah the magic bullet. Well we will wait and see.

[Graham Hickling]

I'd take 720p60 over 1080i any day.

Being that it's 2005, interlaced footage of any sort should be led down to the barn and quietly put out of its misery.

[Thomas Smet]

I agree Graham. Two of the things I hate the most about video is interlaced frames and pixel shift. Well with NTSC I also hate non square pixels and 29.97 fps instead of 30.

Interlaced is a form of compression that tries to get more detail into a certain bandwidth. Nothing in the real world is interlaced.

[Ron Evans]

Nothing in the real world is 24p either!!!!

Ron Evans

[Ken Hodson]

I'll state the middle ground. We have two eyes that make one image. Thats sort of interlaced. But our eyes see whole frames so that would be progressive. Sort of dual field progressive?

[Graham Hickling]

I'd say our eyes are closest to two progressive cameras mounted side-by-side, outputting stereoscopic images for later viewing on our new glasses-free 3d monitors:

http://www.stereographics.com/products/synthagram/synthagram.htm

(Note that this is an LCD monitor - so there's no interlacing going on here either...)

[Giroud Francois]

purely on a marketing point of view...
producing displays (lcd/plasma .. crt are dead) is a matter of pixel.
or a matter of pixel per dollar.
So imagine some company producing a display with 1920x1080 pixel when half of them will be not used half of the time.
Seems we will likely see more 1280x720 downconverting 1080i .
it is cheaper, easier to produce and you still can stick an HD compatible logo on it.

[Ron Evans]

Actually 24fps film projected from a film projector and interlace video both fool our eyes. BOth stem from the economics of technology at the time of introduction into providing the best way to fool the eye/brain into perceiving fluid motion at the best price. The film projector normally has a three blade shutter that flickers the image so that our eyes think they are seeing 72 fps but there are only 24 unique images ( the screen doesn't flicker but it does stutter since our eyes perceive flickering if that is below about 60 images a second). Interlace video takes advantage of two forms of latency, the phosphors in the crt and the latency combination of our eyes and brain. At 60 fields a second moving parts of the image result of course in the image being a 60th second displaced in the two fields. This is where our brains come in to play and morph these together it fluid motion. ( unless of course the image is relatively fixed and there are thin lines that don't really move. Our brain thinks this is flicker!!!!) At 60 fields a second the interlace flicker is right on the limit and the crt phosphors decay slower than the next interlace field is writen, at least that is the theory!!. To display 1080i there needs to be 1080 horizontal lines since these are displayed ( for a very short time ) together, one set decaying and the other set being writen, they are not the same 540 lines displayed twice!!. 720p doesn't cut it for a 1080i or 1080p source, but a 1080i or 1080p source will happily display 720P ( with bars !!) Any attempt to fill the screen from either of these approaches will degrade the video. Witness the terrible display of normal SD video on any HD set( creating more resolution from rubbish creates a wonderful display of rubbish!!!). If you shoot 1080i get a 1080i display likewise for 720p and in my experience SD is best displayed on a good SD display. Progresssive displays still need to get above the eyes flicker rate and still use the latency of the displays during the flicker cycles. They just use different means of doing this but they ALL fool our eyes, its just how they do it that differs from CRT , LCD etc. At the moment CRT's have the edge in the combination of resolution and refresh rate but they are big and heavy. For me the the vision is progessive capture above the flicker rate ie 1080p60 or above. Untill then a love my FX1 and Sony HiScan 1080i TV

Ron Evans

[Graeme Nattress]

But 24fps on a DLP projector doesn't flicker. It looks great - as does 24p on an LCD display.

Also, to complain about NTSC uprezzed to HD on an HD display assumes that the SD NTSC has been broadcast, and quite frankly that we see a picture at all is quite amazing after all the compression it's gone through. If you were to uprez the SD master before broadcasting, to HD, then it look a world different to what it looks like with the TV uprezzing it.

Indeed, 720p more than "cuts it" for a 1080i source, and even blowing up 720p to 1080p will be invisible to most viewers.

Indeed 1080p60 will be awesome, but nobody shoots it, and hardly anything displays it. However, when things change it will be nice.

Graeme

[Prech Marton]

I have some imax hd dvd-s: speed, coral reef, etc.
The disc contains the 720p and 1080p version of the film.
But the file size is almost identical (2gb).
What does this mean?
The 720p version show less mpeg artifacts?
And the 1080 is sharper because the resolution, but show more mpeg-block?

[Peter Wiley]

http://www.highdef.org/library/index.htm might be helpful in sorting some of these issues out.

[Kevin Shaw]

Theoretical arguments aside, from a practical standpoint we would all be MUCH better off right now shooting 720p at 60 frames per second and delivering finished videos at either 720p60 or 720p30. Interlaced video is about to die quietly because the TV and computer screen manufacturers are reportedly phasing out all tube-based displays in favor of more modern digital solutions, almost all of which will be progressive-scan by nature. And a lot of even the most expensive HDTVs are only 720p native resolution anyway (or less), because that's what's affordable to produce using today's technology. Plus 720p is a lot easier to edit and play back on today's computers than 1080i, such that it is currently the most plausible format for actual delivery of HD video projects.

So we have a situation today where 720p is a practical end-to-end solution and 1080i is not, and by the time we have the technology to do 1080i well the displays will all be 720p. Personally, I think 720p is arguably a better format anyway, and it makes no sense to me that we're still talking about interlaced video when debating what format to use for the next 50-100 years or so. As someone else said, let's take that horse out to the barn and put it out of our misery.

[Ben Buie]

One thing to worry about is editing; editing compressed interlaced video is no fun over multiple generations. Interlaced video is much more subject to compression and interlacing artifacts over time than progressive video.

For me it is just one less thing to worry about. We can record, edit, and deliver everything progressive and not even think about it.

Also if you are pulling stills from your video for marketing progressive is nice.

Let's don't forget that 720p (921,600 pixels) is still nearly 3 times (2.7 times to be exact) the pixel resolution of 480p (345,600 pixels), it isn't a "small increase". For broadcast, where most people are used to 480i, the difference is even larger.

The primary reason we haven't "upgraded" to the FX1 or the Z1 yet is I refuse to go back to interlaced. I'm very interested in both the the JVC and Panny though because of their progressive modes. 1080/30p or 1080/24p would be sweet, of course we would have to upgrade our editing computers once again :)

Ben

[Barry Green]

Originally Posted by Ben Buie

Let's don't forget that 720p (921,600 pixels) is still nearly 3 times (2.7 times to be exact) the pixel resolution of 480p (345,600 pixels), it isn't a "small increase". For broadcast, where most people are used to 480i, the difference is even larger.

Nearly 3x in spatial resolution, yes, but also 2x as high in temporal resolution. You're getting almost 6x as many pixels per second pushed through a television screen with 720p as you are with NTSC. And, if I may geek out for a moment, once you factor in the kell factor, that number goes even higher, more like 7x as many discernible pixels per second. 720p's real HD, no doubt about it.