Does the LCD display 'progressive' footage?

A

Aejaz

Well-known member
Barry,

You have mentioned in your book that while the camera captures or sees full progressive frames in the progressive mode, it records them in the interlaced format, and that the recorded footage could be reassembled to full progressive frames by the NLE...

My Qs are:

When we replay a tape recorded in the progressive mode, thorugh the camera's inbuilt vcr, does the lcd panel actually display a progressive footage or an interlaced video (presuming lcd is capable of displaying progressive footage)?

When we replay a tape in the camera vcr and display it on a progressive tv, is the footage progressive?

When we dubb the footage onto a dvd using a commercial dvd recorder and NOT the NLE-computer-dvd recoder (i,e not the 25P timeline)....do we record a progressive dvd or an interlaced one?

thanks
 
Re: Does the LCD display 'progressive' footage?

When we replay a tape recorded in the progressive mode, thorugh the camera's inbuilt vcr, does the lcd panel actually display a progressive footage or an interlaced video
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LCD's are inherently progressive devices. However, I did some experimentation once to determine if the LCD displayed just one field or not, and the results were kind of hard to decipher, but it convinced me that the LCD is definitely displaying both fields, at 60Hz.

When we replay a tape in the camera vcr and display it on a progressive tv, is the footage progressive?
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No, because the camera is an NTSC device, and NTSC is, by design, an interlaced system. However, the footage will retain the filmlike feel of progressive footage, but you can't get a true progressive image out of the camera, it's always interlaced.

do we record a progressive dvd or an interlaced one
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It is possible to encode a DVD as progressive, and get pure progressive playback from it. Play a 24P DVD on a computer DVD player and it'll play back to the computer monitor at a 24-progressive-fps rate, no interlace artifacts will appear. I believe the same is possible when going to a progressive-scan digital television that understands component progressive output from a DVD player, but I don't have any direct evidence to support that.
 
Re: Does the LCD display 'progressive' footage?

[quote author=Barry_Green link=board=Events;num=1101318719;It is possible to encode a DVD as progressive, and get pure progressive playback from it.  Play a 24P DVD on a computer DVD player and it'll play back to the computer monitor at a 24-progressive-fps rate, no interlace artifacts will appear.  I believe the same is possible when going to a progressive-scan digital television that understands component progressive output from a DVD player, but I don't have any direct evidence to support that.[/quote]

I believe you also need to play the 24p DVD on a progressive scan DVD player on a true progressive scan TV to experience true 24P footage.
 
Re: Does the LCD display 'progressive' footage?

So can we conclude that we do not see the 'real magic' (progressive video) of this camera......untill its progressive captures are processed by the right NLE...and displayed on a progressive screen...say a computer monitor?
 
Re: Does the LCD display 'progressive' footage?

Apart from some small LCD screens (viewfinder types..) all LCD (and DLP) screens show "all the available lines" in progressive mode and are refreshed at field rate (60/50Hz), whatever the source material is . So they all contain de-interlacers and allmost in all cases powerfull rescalers too. For some applications (games..) some high-end LCD screen allow "interlaced mode" too, which in this case means line doubled field display.
Although NTSC is a TV standard which has an interlaced video stream, it doesn't mean it can't be used for progressive capture and perfect progressive displaying on LCD screens. High performance deinterlacers (3 line motion adaptive) even allow progressive display from interlaced footage in a way that only a trained eye on special (moving) testpatterns can see differences against the native progressive footage.
 
Re: Does the LCD display 'progressive' footage?

But as Barry said, there is no way to get progressive footage out of the camera....it is always interlaced. It has to go through the NLE mill to become progressive again.

So!!!! does it mean that

1. what we see in the LCD from a recorded tape is an interlaced footage, and what we see direct from the camera lens (in progressive mode) is progressive image?

2. When we capture the tape image through an NLE, it would still remain interlaced video untill it has been applied to the 24/25P timeline?
 
Re: Does the LCD display 'progressive' footage?

Sorry Aejas but Barry is not correct... The way a picture is being encoded/ transported (NTSC, PAL, isosynchronious DV stream...) has nothing to do with the way it is being captured by the CCD and displayed. The basic point is that you can capture a full frame and display it, whether it is being encode/transported as interlaced or as progressive.
On the Vegas point, I don't know. Most displays don't accept 24/25p in a non interlaced stream.
 
Re: Does the LCD display 'progressive' footage?

While Barry can himself comment, what I gathered from him is that the camera does capture full progressive frames (25/24P), but records them on the tape as interlaced (50i/60i). Hence if played back, the data on the tape 'should' remain interlaced untill it is reprocessed by the NLE into full frames, progressive footage.
 
Re: Does the LCD display 'progressive' footage?

No there is no need for an NLE. Displays can do this job at least as good as any NLE.
 
Re: Does the LCD display 'progressive' footage?

NTSC plays back fields at evenly-spaced intervals in time. For Andre's progressive idea to work, the monitor would have to buffer the fields and only update the display on odd-field increments (for 30P) or, in the case of 24P, it would have to reverse-pulldown the footage, buffer it, and then play it back at 24Hz.

That would not be an NTSC display.

Doesn't mean it couldn't happen, but it wouldn't be displaying NTSC footage. The camera outputs NTSC footage. NTSC footage knows nothing of "frames" or "progressive scan", it only knows that it gets a new field every sixtieth of a second. 30P cannot be displayed as progressive, because for every instant where you see both fields from one frame displayed simultaneously, the next instant you will see two fields from alternating frames, which will display comb artifacts on motion.

The camera can only output NTSC. That's what I was saying. If you have some form of non-NTSC display device that can somehow interpret NTSC footage, buffer fields, display at a slower refresh rate and recombine fields into frames, then yes you could watch the progressive footage straight from the camera. For all I know, those TV sets may already be on the market, but I'm not aware of them (not that I've looked either).
 
Re: Does the LCD display 'progressive' footage?

wow. I didn't know that. I knew it outputs NTSC but I didn't know that the idea of obtaining progressive images would be that hard.
so, If I shot it on 24pA, edited on FCP in 24 timeline, then output to regular DVD- but played it back in a progressive DVD player on a progressive TV, the footage still would not be true progressive right?
unless I had hardware to output true P out of the NLE to a true P DVD encoder?(such a thing?0

so what we are watching everytime we play back 24p on the dvd on our NTSC monitor is the asthetics of progressive images but not played back in true P just as we're not really watching TRUE 24p but pull-down or interlaced. 24p.
 
Re: Does the LCD display 'progressive' footage?

"NTSC plays back fields at evenly-spaced intervals in time. For Andre's progressive idea to work, the monitor would have to buffer the fields and only update the display on odd-field increments (for 30P) or, in the case of 24P, it would have to reverse-pulldown the footage, buffer it, and then play it back at 24Hz." Not my idea Barry, but this is how it works (only a bit more sophisticated than your explanation) for many year now with the display products in the company (Barco) where I used to be VP R&D for about 20 years.
 
Re: Does the LCD display 'progressive' footage?

[quote author=DvPixl link=board=Events;num=1101318719;start=0#12 date=11/25/04 at 13:45:46]wow. I didn't know that. I knew it outputs NTSC but I didn't know that the idea of obtaining progressive images would be that hard.[/quote]
It's not hard to get them, it's that you're wanting to play it back on a non-progressive device.

If I shot it on 24pA, edited on FCP in 24 timeline, then output to regular DVD- but played it back in a progressive DVD player on a progressive TV, the footage still would not be true progressive right?
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Well, what do you mean by a "regular DVD"?  Do you mean that you'd be adding 3:2 pulldown to your 24fps edit?  If so, then the DVD would output interlaced footage.  The progressive TV may know how to de-interlace that footage to reconstruct the 24P sequence however, which would still allow you to see progressive content.

But if you encoded it as a 24P DVD, then your scenario described above would result in progressive output.  You can do this easily by making a 24P DVD and playing it back on your computer monitor, you'll see 24P images played back as pure progressive images.

so what we are watching everytime we play back 24p on the dvd on our NTSC monitor is the asthetics of progressive images but not played  back in true P just as we're not really watching TRUE 24p but pull-down or interlaced. 24p.
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Yes that's correct.  An NTSC monitor is an interlaced device.  It cannot display progressive images.  It can display progressive images that have been split into NTSC-compatible fields, but it will display one field, then 1/60th of a second later it will display another field.

You can obviously display footage that has the temporal feel of progressive, which will differ from interlaced, but NTSC is interlaced, so an interlaced television will display the image as interlaced.

If you display 30P footage on an interlaced television, there will still be interlacing going on.  Do a horizontal pan across black/white objects (like a picket fence, for example) and you'll see comb artifacts all over the footage on the edges.  Display that on your computer screen (a progressive display) and you won't see any comb/interlace artifacts at all.

Now, there are some televisions that proclaim something about 3:2 pulldown removal -- I haven't used one of those, but maybe they actually change their scanning rate and do some sort of inverse telecine on footage... heck, maybe they're multiscanning monitors that can display true progressive footage, I don't know.

But getting back to the original question: the DVX outputs interlaced footage. NTSC is interlaced. If your monitor can somehow interpret that and display it as non-interlaced, non-NTSC, progressive-scan footage, then I guess you could get "true progressive" out of the camera itself. But if you're talking about an NTSC television, those are interlaced.
 
Re: Does the LCD display 'progressive' footage?

[quote author=andre link=board=Events;num=1101318719;start=0#13 date=11/25/04 at 14:29:57]Not my idea Barry, but this is how it works (only a bit more sophisticated than your explanation) for many year now with the display products in the company (Barco) where I used to be VP R&D for about 20 years.
[/quote]
Andre, I see where you're coming from, and obviously you know way more about that than I do. Yes, if one had some sort of specialized display that is actually a multiscanning monitor that can interpret footage, de-interlace it, field-buffer it, and change the scanning rate, that's very, very cool in fact...

My point was that's not technically an NTSC display device, as it would not be displaying NTSC as recorded. It might be able to interpret an NTSC stream and reconstruct it and IVTC it and display it, but that wouldn't be showing what the camera recorded. It's not showing NTSC 60 field video. And the DVX only outputs NTSC, as interlaced fields.

I'm not doubting your experience or expertise, as you can tell I'm clearly not as familiar with that level of product as you are.

But these guys are asking if they're seeing progressive on their televisions, straight from the camera, and the answer is no. They're seeing an interlaced recording of a pulldown-introduced progressive capture. That would have to be interpreted or modified somehow before they could see it as progressive.

So, in summary, if I may... if you want to watch the true "progressive magic", as Aejaz called it, you either:
1) watch it on a computer monitor from your 24P timeline, or
2) make a 24P DVD and play it on a progressive-scan DVD player hooked up to a progressive TV, or
3) watch it on a multiscanning-capable, frame-buffering display device such as a Barco projector.
 
Re: Does the LCD display 'progressive' footage?

And while there is no pull down in the PAL progressive footage, the same also stands true in case of the 25P video, right?
 
Re: Does the LCD display 'progressive' footage?

thanks Barry for the thorough answers. I would buy you coffee if I knew you personally.
 
Re: Does the LCD display 'progressive' footage?

Instead of buying him a coffee...think of buying his latest book on the dvx ;D...if u have not already.
 
Re: Does the LCD display 'progressive' footage?

The answer to basic question: "Does the LCD display 'progressive'footage" is YES ALLWAYS and for all brands of LCD/DLP monitors/tv's, whatever the original footage is, interlaced or not, NTSC or whatever, 24p, 25p, 30p, 50/60i. The time that image displaying and capture were interrelated is gone for several years now, by design for LCD/DLP, but even for higher end CRT displays.
 
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