[Tom Brooks]

Is there a down side to the PNG suggestion?

[Tom Brooks]

I’m suggesting 24P for the purpose that the original post stipulated and nothing else–a progressive DVD player with a progressive display.

Forget about interlaced. Why? Because the available playback medium in this case is progressive. With properly encoded 24P material, the player will assemble the fields into frames and then repeat frames in a 3-2 pattern to accurately display 24P.

Now, nobody who has posted here seems to know whether standard def DVD can display 30P progressively. I suppose it can if you have a system of encoding the video with the flags necessary to tell the player to detect 2-2 pulldown and repeat each frame twice in its progressive output. I believe a few movies have been realeased in this form. But can Final Cut Studio accomplish this? If not, your DVD player and display will be playing 60i and, whether you want to believe it or not, there will be artifacts.

[Tom Brooks]

Stephan,
You should be able to shoot in 30P and capture and edit in regular DV NTSC with no rendering. If you change the sequence setting to Field Dominance – None, I don’t think it changes that.

If you are still experimenting with what looks good to your taste, I have to say you should at least try 24P. 24PA is the best shooting mode for this if you are to end up with a 24P DVD. Your original post stated that your playback would be progressive DVD to a progressive monitor. Many of the guys suggesting 30P must have ignored that because you will not get a true progressive DVD with 30P.

Only a 24P workflow is directly aimed at a 24P DVD final product. Try the workflow with 24PA and see what you think.
-Tom

[Tom Brooks]

Shane,
I view the analog component from a Kona LHe on a SD Sony PVM monitor and sometimes on a Panasonic plasma. At the moment I don’t have the right interfaces to view on both at the same time. I’m not saying there’s any stutter or strange motion. Motion smoothness is just what you would expect–it’s regular, consistent, and not as smooth as 60i or 60P.

What I have been suspicious of is a softening of the edges of moving subjects.

It’s the theory of it that I’ve been interested in pointing out and getting reactions on. Everyone but me seems to think that when you play 30P in NTSC you are looking at purely progressive frames. That just isn’t true. You’re looking at interlaced fields at all times and the two fields are not always recorded at the same point in time.

It’s like watching 24P DVD on a non-progressive display, only the split frames are happening at a faster rate and you can’t see them on pause. With 30P it’s a constant, very rapid (59.94Hz) alternating of whole frames and split frames. Another way to look at 60i is that it is ALL split frames. 30P is only HALF split frames.

I made a mistake in one of my earlier posts too. I said that the two fields in the 30P split frames were recorded a sixtieth of a second apart. Actually, they’re recorded a 30th apart.

Try an experiment. Make a simple moving white box in 30P and one in 60i. Play them to an interlaced monitor. Which one looks sharper? To me, the 60i looks sharper. When played on the plasma, the 30P looks sharper.

Granted, the visual effect of all this is way more important than the theory. I’ve been asking the same question as the original post for some time–is 30P a good thing? For me, the jury is out. That said, I’ve shot 30P before and I’ll give it another look based on your support. Thanks a bunch for your interest and I hope I haven’t wasted your time. I’m afraid my Cow addiction is getting the better of me!
-Tom

[Tom Brooks]

Interesting tip that I’m sure a lot of 30P experimenters might miss at first.

[Tom Brooks]

[Dave LaRonde] ”
Well, if you can see the interlacing at 29.97 WITHOUT figuring out a way to pause on the wrong field, then more power to you.”

Whether I can see it or not, especially in PAUSE, isn’t completely the point. That’s the great thing about 30P. Paused, it looks great. But when the video is moving, I stand by the contention that, in 30P NTSC playback, there are fields with motion recorded a sixtieth of a second apart which are interlaced together. If they’re there, you can see them, albeit in a very subtle way. You don’t get all the benefit of 30P when you play it in NTSC. You get 2/3 of the benefit.

A wealth of stuff to think about and at least a couple real-world tips to take home from the herd. Hope my devil’s advocacy didn’t hijack the original post too much.

[Tom Brooks]

Dave,
That’s why I said please enlighten me. Working in the field you do I have no doubt you know a lot more about the makeup of the TV image than I do. I guess what I’m getting at, or trying to, is that there’s no free lunch with 30P. Believe me, I’m seriously trying to grasp this. If I find a way to SHOW this concept I’ll be sure to let you in on it. Meanwhile, we can all have fun working in the multitude of formats on the market at the moment.
-Tom

[Tom Brooks]

[JeremyG] ”
That doesn’t make sense, Tom. You’d have to have 60p to achieve what you are saying.

30p is still 60i, just that each field in any given frame is identical.”

Yes, that’s completely true and I get that, but I still see Barry Green’s point that 60i is going to interlace every field with the next field and therefore, fields with different motion will be interlaced.

[Tom Brooks]

The way I understand it, you have to think in terms of 60i, not 30. Where do those 60i fields come from? Field-1 comes from frame A, Field-2 comes from frame A, Field-3 comes from frame-B. That’s where the interlace look comes in. The problem is that the 60i display is interlacing each field with the next. So those last two fields, taken from different frames will be interlaced. And they look it because they have different motion recorded in them.

[Tom Brooks]

[Russell Lasson] “If you shoot at 30P then you have one complete frame every 1/30th of a second.”

But when the 30P is shown in NTSC, every 60th of a second, you’ll see a field from one 30P frame combined with a field from the next 30P frame. This is one of those things that makes me crazy. In practice, the 30P still looks good, but why bother for NTSC? It looks great in Windows Media. No need to deinterlace.