Why do you need/want progressive?

[John Hewat]

I saw that the V1 had progressive and I thought "Awesome - I want it."

And then I thought, "But for what purpose?"

And I tossed up a few reasons.

1. My Z1 footage looks beautiful but I have LCD screens on my PC and will soon get a Plasma or LCD TV for the living room, and these are progressive screens, so... progressive wins.

2. I have plans to shoot a feature in a few months and could use progressive if I ever have the opportunity to go to a film out. But there's plenty of Smart De-Interlacing workflows for Z1 footage, and unless some miraclulous opportunity arises, I probably won't be going to film... so interlaced wins.

3. I got to play with a V1 and the progressive display on the monitor displayed the horrible jerkiness in movement that made me prefer interlaced.

So... someone please tell me why I need (or why I would want) a progressive camera. Or better yet, can you please tell me why YOU want progressive.

If I have some idea of its practical application then I will feel better equipped to make a decision.

Thanks,
-- John.

[Piotr Wozniacki]

Both my 42" plasma TV and the 24" 1920x1200 LCD monitor deinterlace the component HDV 1080i absolutely perfect.

[John Hewat]

Thanks Piotr,

On that note, I'm looking for a good 24" 1920x1200 LCD to get at the moment. I'm looking at the Samsung.

What's the 24" LCD you use that de-interlaces?

And you mention that it de-interlaces the Component HDV - will it de-interlace footage on my PC? And will it de-interlace footage on DVD?

[Jarrod Whaley]

Most people see progressive as "cinematic" and interlaced as "realistic." If you don't want to let vague notions of what "most people" think dictate your choice to you, then the choice is almost entirely an aesthetic one. If you like progressive, shoot progressive. If not, then shoot interlaced. It's up to you.

Are you shooting this stuff only for your own use, John? If not, then all this talk of which display you own becomes much less useful as a deciding factor, since you have no idea what display(s) your audience will be using.

[Piotr Wozniacki]

John, apart from aesthetic ("film-like" etc) differences with progessive, I find the interlaced HDV material absolutely astounding on both displays (the monitor I have is Fujitsu-Siemens P24-1W). While the component input is being properly deinterlaced when I hook up the camera to it, a raw .m2t file played back with just any mpeg software player does show the jugged edges of course. It's up to the particular player (and computer power) how well it can be de-interlaced.

Regarding the aesthetics, I don't know yet - I must admit I never saw any progressive HD video on my particular displays. But then, I've noticed that some hollywood DVDs contain progressive mpg's and others have interlaced stuff on them - I personally see no difference, my SD DVD player being "progressive scan" and also connected via components...

So frankly, unless I see the V1 25p footage live and it's absolutely different (and better to my liking) that the regular 1080/50i I've been using so far - the only real reason for me to pick the V1 rather than the FX7 will be the XLR inputs alone... Of course there're many more differences I'd fancy, but are they worth the price difference - I'm not sure (in my case, of course).

[Steve Mullen]

Originally Posted by Piotr Wozniacki

Both my 42" plasma TV and the 24" 1920x1200 LCD monitor deinterlace the component HDV 1080i absolutely perfect.

The odds are that this is not true unless you have a Hitachi, JVC, and Pioneer.

http://www.hometheatermag.com/hookmeup/1106hook/

And, if you shoot 25p, carried within interlace, I suspect it's still interlace.

24p, carried within interlace, can suffer from both cadence and interlace issues.

Only 30p and 60p (non-interlaced) can be sure of being displayed correctly with the majority of HDTVs.

[Piotr Wozniacki]

Steve, I don't do 24p (I live in a PAL country). Also, I've never put my particular displays through any analitical test device but my own eyes, and yes - they both de-interlace properly when feed through component. I can say that for sure, because any 1080i material showing no interlacing artifacts through component, when captured to a .m2t file and played back with a software player with a de-interlace option OFF, shows combs on all moving vertical edges. I don't see any difference in resolution either.

So, I must have been very lucky with both my displays, in the light of the article you're linking to. I must clarify that - while the LCD monitor is full 1920x1200 - my Panasonic 42" plasma is only 1366x763, but is compatible with 1080i and also deinterlaces well.

[Steve Mullen]

Originally Posted by Jarrod Whaley

... since you have no idea what display(s) your audience will be using.

This is real issue. The majority of HD production was/is monitored with interlace CRT monitors. At one point, all HDTVs were also interlaced CRT monitors. So those in broadcasting saw no issues with interlace. (Or, they liked the number 1080 more than 720.)

All computer folks knew this was a huge error, but the ATSC gave in and allowed interlace. Something the EBU has tried to avoid doing.

Now that all flat-panel HDTVs are essestially computer monitors, most all HD is being produced in interlaced but watched on progressive monitors. As the computer folks knew, there is no way to deinterlace motion video without the loss of vertical resolution.

Either the entire screen has a 50% cut, or the moving objects do. The latter is much better, but is so expensive to do correctly, that most HDTVs don't have the correct chips to do it.

[Piotr Wozniacki]

Originally Posted by Steve Mullen

Either the entire screen has a 50% cut, or the moving objects do. The latter is much better, but is so expensive to do correctly, that most HDTVs don't have the correct chips to do it.

Do you think I wouldn't tell a 50% cut in resolution? This would be lower than that of an SD, progressive 'factory' DVD. All my 1080i video has far more detail that any SD DVD on the displays in question!

Frankly, when buying the LCD I was very suspicious how it would display my HDV; I was very positively surprised?

I'm not saying that what you (and the article) mention is untrue, let's try and solve this 'mistery' as I bet many would benefit!

[Tom Roper]

Originally Posted by Steve Mullen

Only 30p and 60p (non-interlaced) can be sure of being displayed correctly with the majority of HDTVs.

True for 1080p displays. But until any of the HDV cams including the V1 can manage true native output without interpolation, it's quite arbitrary to obsess only over the vertical loss from discarding field lines on 1080p monitors without acknowledging the horizontal resolution loss from interpolated 960x1080 imagers and the 1440x1080i HDV format itself.

In other words, the argument of whether or not the signal is being displayed "correctly" on a 1080p monitor has been framed in terms of whether or not you lose resolution when deinterlacing the signal. But that ignores that HDV inherently does not display correctly at 1080p because the format loses resolution down to 1440 horizontal.

As an aside, 2:3 pulldown while defacto is a jumpy kludge to accommodate the 29.97 fps transmission standard. 24 fps is film-like. 2:3 is not. It thrives on you not being able to spot its irregular cadence.

In the end, 1080p24 HDV for most viewers will carry its own set compromises. As evidence of that, you have people right here in these forums using a variety of monitors viewing a variety of mixed programming, and yet no concensus.

[Stephen van Vuuren]

Originally Posted by John Hewat

So... someone please tell me why I need (or why I would want) a progressive camera. Or better yet, can you please tell me why YOU want progressive.

If I have some idea of its practical application then I will feel better equipped to make a decision.

Thanks,
-- John.

Like many people, it sounds like you are confusing frame rates with progressive vs. interlacing. Interlacing is the act of shooting alternating frames on alternating lines, thus each frame is only 50% of the image and thus is called a "field".

Interlacing is an ugly, artifacting crutch that exists only because bandwidth was very limited in the beginning days of video/TV.

To understand this issue clearly, here's a breakdown of frame rates as well as interlaced and progressive issues:

(1) 24p - This actually refers to two different qualities. One, the image is captured and recorded as single image moment in time - like a still or motion picture camera. Second, 24 of of these single image moments are captured each second. 24p is actually more correctly called 24 fps progressive.

(1a) 25p - Same but compatible with PAL systems

(2) 30p - the exact same process as 24p but at 30 fps

(3) 60i - This is the weird one (and unfortunately most video is here). Each frame (thus called a field) is captured at 50% resolution on alternating odd and even lines and stitched (interlaced together). Sometime is incorrectly referred to as "30 frames per second" by people who think since each field adds up to a frame, you have 60/2 frames = 30.

This is not what happens visually - 60 separate images moments are captured per second and 60 fields per second are displayed to the viewer (assuming no deinterlacing). So 60i is 60 frames per second but each frame is only at 50% resolution.

You can easily see this effect by pausing 60i material with high motion on a device (like an old VCR) that does not attempt to cover up the interlacing and see the horrible judder of motion split across the two fields. Truly an ugly thing.

(3b) 50i - same as above but PAL

(4) 60p - is the same as #1 & #2 but displays at 60 frames per second.

(4b) 50p - PAL version of 60p but rarely used in camera design

When people refer to the "stuttering, jerky look" of 24p video or the "realistic motion" of 60i, it's very important to understand what is actually going on.

Most video displays (and many decks, editing systems etc.) on planet earth are 60i (50i in PAL countries). Thus, video shot at different rates must be adapted for interlaced systems.

24 fps progressive needs something called "pull-down" applied to allow it to be viewed/processing on interlaced systems. For motion picture film, this process is done using telecine. 24p cameras use "reverse-pull-down" to hide their true 24 frames per second in the 60i signal and appropriate NLE software can extract the original 24 progressive frames without any loss.

But there's another big issue often ignored here and that's shutter speed. Shutter speed is a huge factor in determining the look/feel of images, both still and moving. If you shoot at 60 frames a second (60p or 60i - it does not matter and this is a very important point), the slowest shutter speed you can get is 1/60th of second (matching the frames per second).

The slower shutter speeds you see on cameras are in fact a digital effect which when you think about it makes sense as in a true 60 frames per second image capture, the longest increment of time to expose a single image is 1/60th of second and then you must move on to capturing the next image.

The shutter speed determines how much motion blur a moving image has from frame to frame. 1/60th of second does not give very much motion blur (on a still camera, it's relatively easy to hand hold a camera using a 1/60th shutter speed.

However, on a 24 fps camera, you can use a 1/48th (the standard) or even 1/24th shutter speed with gives significantly more motion blur to the look. This creates a very different aesthetic from 60 fps systems.

We won't argue here about which is "better" as the important fact is they are "different". But the combination of frames per second and shutter speed mean many different looks and feel can be achieved.

It's equally important that you cannot compare footage from 24p, 30p, 60i, 60p (and the various PAL variants), unless you know what shutter speeds, pull-down methods and deinterlacing processes are involved.

For example, many people see a 60i image shot with a 1/60th shutter and then watch a 24p images also shot with a 1/60th shutter and conclude the 24p is "too stuttery" without realizing the shutter speed is major factor in the look. Shoot some 60i video with a 1/120th or even 1/240th of shutter speed and see what happens for a quick illustration.

Also, watching 24 fps at 24 fps can be misleading. 35mm motion picture film is usually seen by most people at either 29.97 fps (on TV, DVD) or in a theater where projectors double project each frame at 1/48th of second to help with image display.

After all this (for the few that made it this far), the bottom line is that you never want an interlaced camera, you always want a progressive camera. What's important is the frames per second it shoots. You may "need" or "have to have" an interlaced camera for compatibility reasons, but there is zero visual advantage to interlaced and many ugly artifacts that result from it, the most signifigant is the up to 50% loss of resolution on moving subjects or camera motion.

24 fps images have a cinematic slightly unreal look to them because it's capturing images slower than the average eyes operate (thus the common 60 factor in TV, computer monitors and the like although people's sensitivity to this varies).

60 fps images have a very realistic look to them because it's very close to the average eyes processing rate

30 fps in between, but obviously more like 24 fps than 60 fps (thus it was called "frame movie mode" on old Canon and Panasonic cams).

25 fps is basically impossible to tell apart from 24 fps. 50 fps is very close to 60 fps but not often used yet.

I (and many others) keep hoping interlaced will die the ugly death it deserves, but backward compatibility keeps the damn thing alive. There are a few that argue it's still attractive because of efficiency but they are almost always engineer types and not image makers.

Hope this clarifies rather than confuses.

[Piotr Wozniacki]

Thanks Stephen for your elaborate. I agree that shutter speed is a very important factor to how a video actually looks to human eyes. But on the ever so much discussed subject: "is 25p better than 50i" (in PAL terms) I have one answer: none is better. They both convey the same amount of information. Only when I'm able to buy and use a camcorder that does 50p I'll know for sure this is want I want, because it actually IS better simply because it delivers twice the amount of information to my eyes, when compared with today's systems.

[Stephen van Vuuren]

Originally Posted by Piotr Wozniacki

"is 25p better than 50i" (in PAL terms) I have one answer: none is better. They both convey the same amount of information. Only when I'm able to buy and use a camcorder that does 50p I'll know for sure this is want I want, because it actually IS better simply because it delivers twice the amount of information to my eyes, when compared with today's systems.

Piotr:

25p does not convey the same information as 50i. Images captured at 25p are 25 full resolution images at 25 frames per second with shutter speeds as low as 1/25th second. Images captured at 50i are 50 images at 50% resolution at 50 frames per second with 1/50th of second shutter speed.

When the subject and camera are still, the 50i images will look similar as the interlacing will get close to progressive resolution. But when subject and/or camera is in motion, they fundamentally change.

The 25p captures each move at full resolution but only 25 times a second but with a 1/25th shutter the lowest possible.

The 50i captures each move at half resolution but 50 times a second with 1/50th shutter the lowest possible.

So, depending on camera and subject motion, progressive capture gets varying amounts of more information than interlaced, but importantly at half the frame rate. Thus it's higher resolution but less smooth motion (modified by motion blur).

But it's not the same information.

[Piotr Wozniacki]

Originally Posted by Steve Mullen

The odds are that this is not true unless you have a Hitachi, JVC, and Pioneer.

http://www.hometheatermag.com/hookmeup/1106hook/

And, if you shoot 25p, carried within interlace, I suspect it's still interlace.

24p, carried within interlace, can suffer from both cadence and interlace issues.

Only 30p and 60p (non-interlaced) can be sure of being displayed correctly with the majority of HDTVs.

Steve, I'm using Ulead Mediastudio Pro with an ATI graphics card with both DVI and component HDV outputs so configured, that I can display a 1080i clip fullscreen either via DVI-D or component. Guess what: usual combing through DVI, no artifacts through component, exactly same perceived resolution. Go figure!

[Piotr Wozniacki]

Originally Posted by Stephen van Vuuren

Piotr:

25p does not convey the same information as 50i. Images captured at 25p are 25 full resolution images at 25 frames per second with shutter speeds as low as 1/25th second. Images captured at 50i are 50 images at 50% resolution at 50 frames per second with 1/50th of second shutter speed.

I only meant that 25 full resolution frames is the same pixel number of information as 50 half-resolution frames per second.