24p questions

[Josh Martin]

Hey guys,
I'm looking at getting the xl2. I also want to purchase a Direct To Edit capture device so that I can start editing right away with out having to spend time capturing my footage. This is the question. If I'm using and DTE capture device, will it capture the 24fps or does the xl2 only record the 24p to tape first, and then outputs it when played back from the tape. If the xl2 will only output the 60p through firewire, then it would be useless to have a DTE device because it would only capture 60p instead of 24p. Is this right? Help me out here guys. I hope this makes some sense.
Josh M.

[Rob Lohman]

60p does not exist in consumer camera's with the exception of
one HDV camera I believe.

Anyway, as with the DVX100 the XL2 does *NOT* record 24p
(to disk, firewire, whatever). Yes, it scans the CCD's at 24p, but
it does a 3:2 (or 2:3:3:2) pulldown to turn that into 30p before
it goes out. So any standard DTE will function and record this
30p signal which you would also get when capturing.

In your NLE you select the 24p template and it will remove the
pulldown to get your true 24p back. Keep in mind that 2:3:3:2
pulldown is beter suited for editing.

[A. J. deLange]

The camera must convert to DV format which is 60i (in NTSC) and that is what will go out over the Firewire be it from playback or direct. In 2:3:3:2 if the field sequence is A1A2 B1B2 B2C1 C1C2 D1D2 (note that A1 and A2 represent odd and even lines from the same exposure) then it's clear that the NLE, can recover the 24P (or 23.976 actually) by simply throwing away the B2C1 frame and so I'm guessing that's how it works. ??

[Barry Green]

That is how it works. With 2:3:3:2 pulldown, for every group of four 24P frames, the tape records four full frames and one disposable "split frame". When using an NLE that understands 2:3:3:2 pulldown, the NLE can simply discard the split frame, and be able to display/work with the original raw 24P frames.

[Raymond Schlogel]

" Keep in mind that 2:3:3:2 pulldown is beter suited for editing. "

From what I read in the manual, 2:3 is what you should use if the end result is for television and 2:3:3:2 is if you plan on transfering to film. Could you expand on why 2:3:3:2 would be better for editing ? And what would be the difference if you shot on 2:3:3:2 but were going to display it on a television.

Sorry, confused.

- Ray

[Rob Lohman]

The difference for display on a TV is in the way motion looks,
please take a look at the two diagrams on the following page:

http://www.adamwilt.com/24p/#24pRecording
(Under "How is 24p recorded? What's the difference between 24p and 24p Advanced?")

The first image displays 2:3 pulldown where the second one
displays 2:3:3:2 pulldown. The top row represents the capture
as it is coming of the CCD's. The middle represents the frames
as they are laid to tape (or send over firewire) and the last row
shows the re-assembled frames.

The middle row is the most important:

2:3 => AA, BB, BC, CD, DD
2:3:3:2 => AA, BB, BC, CC, DD

As you can see frames 3 & 4 is where the difference in every
5 (original it was 4 in 24p) frame sequence is located.

Now if your NLE needs to do an inverse pulldown to reconstruct
the original 24p it can simply drop the third frame in every
sequence in the case of 2:3:3:2. That is the frame "BC" in this
example. As you can see removing this frame will result in the
original 24p sequence of AA, BB, CC, DD

Now with a 2:3 pulldown it cannot do this since it needs both
frames 3 & 4 to reconstruct the C frame. So it takes a C field
from frame 3 (BC) and frame 4 (CD), then drops frames 3 & 4
and inserts the newly created frame. As you can imagine this
requires more processing power to do (especially at 30/24 fps).

The reason they claim 2:3 is better for tv broadcast is that you
smooth the fields out a bit better. Whether it will be that
noticable in the real-world I don't know (not in NTSC country
here, so no 2:3/2:3:3:2 pulldown in our camera's).

So you can edit both (lossless), but one should be a bit faster
to work with. How much faster I don't know. Some testing of
both methods might be in order if you go the broadcast route.

If you are just making a webmovie or a shoot for a potential
film blowup then it is better to go with 2:3:3:2 since you can
just drop one frame and be done with it.

[David Lee Miller]

I shot 24p (not advanced) 16X9 footage on the XL2 & am having real problems.

First I can't get FCP to see the camera on my G5...I did get it to work on somebody elses G5, but not mine. What could be the problem here?

Then I put the tape in my GL-1, and I got FCP to see it. Is that cool? Can I use the GL1 to capture and not lose anything, i.e. still be 24p 16X9?

Next, with the captured footage that was shot on the XL2, but captured using a GL1 I just couldn't find settings that worked (assuming it's cool to use the GL1)...

I get streaking. I get footage that needs to be rendered. I get footage that looks stretched. I just can't get it right!

I'm freaking...I'm making a feature that mixes media, footage from all kinds of cameras (which is why I didn't go for 24p "advanced" just normal 24p). I wanted my main camera to be native 16X9 24p and super hot, mixing with footage from all kinds of cameras including Digital 8s.

So, assuming I can even get my computer to see my XL2, and I can get the footage in there...then what? What happens when I bring in GL1 footage, & 8mm footage?

[James Millne]

The footage shot using your XL2 and captured using your GL1 will be the same assuming the heads on the GL1 are clean and undamaged. I'm not sure what you mean by "streaking" but I am hazzarding a guess that its the banding that usually occurs because of dirty heads. I am assuming that the problem lies in the GL1 heads as i presume the XL2 you have is relatively new.

Once your footage is captured I believe the problem lies with how you have your timeline setup. Make sure you have your timeline set up at the right framerate of 24p as well as the right pixel aspect ratio. I suspect you have pixel aspect ratio set wrong and that's why it appears stretched.

I have never used FCP so am not able to help you with where to look specifically in that application but i'd imagine the setting will be in some sort of preferences/properties menu.

Hope that helps.

[Douglas Robbins]

Many of the issues you're discussing have been worked out on a thread on lafcpug. Check it out http://www.lafcpug.org/phorum/read.php?f=1&i=70752&t=70548

Short answers I will note here.

1. If your G5 cant "see" your XL2, but another G5 could, clearly you have some set up or settings issue. Check cables, try new firewire, try different firewire ports, check capture settings, try NTSC Basic, if all else fails.

2. Yes assuming the heads are in similar allinment the GL2 should work fine.

3. Unclear what "streaking" is. This could very well be the results of dirty heads on the XL2. Check out your owners manual and see if the dirty head photo looks like the streaking you are describing. There are some reports of brand new XL2's coming from the factory needing their heads cleaned before the camera can be used for the first time. If you recorded with dirty heads, there's no saving the footage. Clean the heads with a dry head cleaner like Canon's DVM CL or Panasonic DVM CL. Do not use any other brands. It's also possible the GL2 is the one with dirty heads. Check it out.

4. You say your footage looks "stretched" but you probably mean it looks "squeezed." This is because you need to capture with the anamorphic setting turned on. You're still going to have to set FCP to handle 24p in he 3:2 pulldown. See Steve Zinn's awsome webpage for more details. http://www.mandarinpictures.com/stephenzinn/

5. Mixing 24p 16:9 footage with your GL2's 4:3 60i footage will look clunky. Also you will have some difficulty editing the footage all on the same timeline. Timeline will either be in 29.97 or it will be in 24.97.

There are workarounds, however, such as turning your GL2 footage into 24p using software like Nattress (http://www.nattress.com/index.htm). Then you can edit all footage on the 24p (really 23.97) timeline. But be careful, Natress conversion only works correctly if you've shot your GL2 footage in 60 fps to begin with.

As to getting good quality 16:9 out of your GL2, you will have to purchase an anamorphic lens from Century Optics. http://www.centuryoptics.com/products/dv/16x9/16x9_37mm.htm

Of course you don't have to shoot your XL2 footage in 24p 16:9. If you shot in 4:3 60i, you would have an easier time matching the GL2 footage.

Douglas

[David Lee Miller]

thanks for the suggestions...I'll try them out...

I hope the heads weren't dirty on the XL2, it looks good in the viewfinder/LCD when we replay on the camera.

[Curtis Gwinn]

Please forgive me if this question makes no sense, but I wanted to see if anyone could help.

I just got my XL2, and out of the box, when I shoot in 24fps there's an image lag in the view-finder. In other words, if I pan, or move quickly, the image in the viewfinder drags for a split second.

Is there a way to correct this, or does it not show up that way when you burn your footage to disc?

Thanks.

-C

[Chris Hurd]

I think it was Barry Green who said that everything all those DVX100 users had to learn about properly using 24p, will have to be learned all over again by XL2 users.

24p is an amazing feature but you'll need to revise your shooting habits in order to accomodate its limitations. The smoother and slower your camera movements are, the better they'll look when shooting in 24p.

[Barry Green]

Yeah, I'm not sure of the exact effect you're experiencing, but it may just be that you're not used to the slower frame rate? In 24p the screen's getting updated only 40% as often as it does in normal video. But even so, you shouldn't be able to actually detect a lag, I mean, 24 times a second is still pretty darn quick...

[Douglas Robbins]

I suspect this is not a 24p issue. This might be image stabilazation at work. Try turning image stabilization off and see if the lag is still there. Let us know.

Douglas

[Chris Hurd]

Good point, Douglas -- that's always a factor too.

Make sure that OIS is turned off whenever shooting from a tripod.