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-   -   24p questions (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/34265-24p-questions.html)

Yi Fong Yu July 14th, 2004 09:34 AM

24p questions
 
if you use both in a 2 camera shoot/setup you won't get matching qualities, correct? i know i could set both to the same 30 and it will match but if i use xl2's 24p it won't match the xl1s in post right?

Peter Moore July 14th, 2004 11:15 AM

The look will not be the same that's right. There probably will be noticeable differences. Keep in mind you'll have to convert both to 60i in order to use in the same project also and you won't be able to go back to 24p then (not easily anyway).

Desmond Sukotjo July 17th, 2004 11:34 AM

24p 30p 60i on PAL
 
I was wondering if the PAL version would be 24p 25p 50i. Is there such thing? Or this option is for NTSC only?

Thanks

Chris Hurd July 17th, 2004 01:48 PM

PAL frame rates are 25p and 50i only. The human eye can't detect any difference between 24fps and 25fps anyway. Converting 25p to 24p for film transfer is a fairly straightforward post-production process. Hope this helps,

Mark Kubat July 20th, 2004 09:46 AM

24p "strobing" in LCD/eyepiece during shooting?
 
Hi folks - the DVX100 LCD display is known to give a funny "strobing" as it compensates in realtime while shooting in 24p mode and my Canon rep who has access to an XL2 is saying that he feels the XL2 is doing the same thing - you really don't get a sense of the 24p/30p until you actually capture the footage and play out live after editing/rendering.... Shooting 24p with the eyepiece and moving around to pull focus etc. is darned irritating in the DVX100 and I have to admit that as a result, this feature would seem to be limiting given the XL2 only has 2 inch LCD/eyepiece... any thoughts?

It's difficult to use auto-focus in the DVX100A - I only have older version avail. to me - because of the processing delay in 24p? - is this also the case in the XL2?

Should maybe do more homework here but just thought it'd be easier to ask outright - is autofocus supported in XL2 while in 24p mode? Is there still a "delay?" that essentially renders autofocus in 24p as being un-useable?

The DVX100's "focus markers" at least help compensate for this a little bit...

Can anyone recount early experiences shooting in 24p with XL2?

Salazar Cragmore August 6th, 2004 09:39 AM

A recommended realtime NLE for XL2 24p footage?
 
Hello.

I am new to DV filmmaking and am looking to setup a camera and editing package based on the XL2. I am looking to shoot an indie featue in 16:9 / 24p to have the option of printing to film. The XL2 looks like it will do it's part, but I'm a little lost as to what I'll need on the editing side.

Can anyone recommend an affordable realtime NLE system (hardware and software) setup that would be appropriate for such a project?

I looked into the Matrox RT.X100 Xtreme, but it seems as if it's not 24p compatible.

I am looking for a PC based option.

Any suggestions would be appreciated.

Thanks,
Salazar

Kaku Ito August 6th, 2004 10:12 AM

Maybe Avid Xpress DV?

Brian Gauthier August 6th, 2004 10:46 AM

your best bet might be Vegas... but check it out...

Richard Alvarez August 6th, 2004 02:33 PM

If you want a true realtime hardware/software solution for the PC. Then AvidXpressDV with MOJO is your best bet. Total price of the software and Mojo will run in the neighborhood of 3 grand. (Not counting the computer system).

Avid, Vegas and Premiere all have "realtime" capabilities. Meaning their software uses various methods for giving you "realtime" previews. If you are shooting in 24 with transfer to film in mind, and don't have a lot of effects and rendering to do, then they will all pretty much give you realtime out as you edit.

Rob Lohman August 7th, 2004 04:22 AM

Make sure the NLE you choose understands 24 fps DV (2:3 or
2:3:3:2 pulldown), like Vegas does for example.

p.s. one small comment. I don't know what you are planning to
do etc, but it kinda sounds like you are going to pay a lot of
money for a (good) camera and then try to get everything else
as cheaply as possible. Again I don't know how you are
approaching this, but there is a lot more to acquire then just a
camera and an editing station. If you those two things are just
the two things you can barely afford then it might be better to
look at some other options.

John Mercer August 7th, 2004 04:47 AM

Avid Xpress Pro, Vegas (PC only) and FCP (Apple Mac only) all have the ability to capture and output 24p advanced pulldown. However Avid Xpress Pro requires Mojo for output and cannot handle 24p standard pulldown at the moment. I am not sure about Premiere. Non of them require the DVX100 (or XL2) for capture or output - the cadence is part of the software and the way it was shot - any deck will do, although obviously you can only shoot 24p on a camera like the DVX100 or XL2 when it arrives.

A word of caution: 24p advanced is specifically designed for output to film. It has a different 'pulldown' sequence than 24p standard, which is more akin in its look to normal telecined film on NTSC.

If your main intention, truly your main intention, is to go to film output then you should shoot in 24p advanced and you will need one of the above NLEs. However if film output is a remote possibility, which seems to be the case for most people - not saying this is so for you - then you would be better off using 24p standard - 24p advanced has a kind of judder that some find unacceptable on NTSC monitors.

Best regards,
John.

Barry Green August 8th, 2004 02:58 AM

If you're going to be editing on a 24P timeline, 24P Advanced has several advantages -- easier pure-frame extraction, plus it uses the full-frame DV compression option, rather than the field-by-field method used for interlaced frames. And there are reasons to shoot 24PA other than film transfer. Editing in a 24P timeline allows for easy creation of a pure 24P DVD, which lets you fit 20% more info on a disc (or, alternately, encode at a higher bitrate for better quality). Also when editing in a 24P timeline you would spend less time rotoscoping or masking or compositing, because there are 20% fewer frames to work with.

If you are going to videotape, you can shoot 24P Normal and edit it in a 60i timeline. If you intend to be editing on a 24P timeline, you should unquestionably shoot 24P Advanced mode.

Bill Pryor August 12th, 2004 08:13 PM

Are you sure that's right about Avid requiring the Mojo box for output? I didn't know the box had anything to do with 24p.

Jeff Donald August 12th, 2004 10:05 PM

I think Mojo is required for RT.

Bill Pryor August 13th, 2004 08:46 AM

We've got two Xpress Pro systems with no Mojo. I didn't see a need for it. Most all effects are real time, but you have to render those effects before going to tape. Takes up to about 4 or 5 minutes for a half hour program usually, unless there's a lot of chroma key.

John Mercer August 13th, 2004 10:52 AM

"Are you sure that's right about Avid requiring the Mojo box for output? I didn't know the box had anything to do with 24p."

I certainly remember a lot of discussion about it on the Avid forums - people being very surprised that they could capture advanced pulldown, but not output it to tape without Mojo. Maybe they've updated it - but I've not heard anything since.

Have you tried outputing a 23.976 advanced pulldown sequence to tape with your systems? I work in PAL land so I have no chance to put it to the test.

I have Xpress Pro and Mojo and I think there is certainly a need for Mojo - at least for me. It gives you 1:1 uncompressed and allows you to mix native DV with 1:1 titles, graphics and FX - so that everything remains very high quality and does not suffer degradation by using only the DV25 codec. I've noticed a big difference in quality of both DVCAM master tapes and DVD.

Real time fx for software only are on the composer monitor only - everything has to be rendered for blue dot output. Mojo gives you perfect studio monitor sync with your timeline - no firewire lag - with realtime full quality fx output - makes a huge difference for complex edits.

All in all it's one of the best pieces of kit I've bought in a long time.

Valeriu Campan September 6th, 2004 02:27 AM

XL2 PAL 24p?
 
I noticed on a side by side spec sheet (PAL & NTSC) that the XL2 PAL camera has only 50i and 25p format. The NTSC version has 60i, 30p, 24p options. Is it correct? Why not the 24p option for the PAL world?

Rainer Hoffmann September 6th, 2004 02:48 AM

Valeriu,

they don't bother with 24p because 24p and 25p are almost the same. If you shoot for TV, 25p is fine for PAL.

If you shoot for the big screen you just slow down the movie by about 4%. The difference between 24 fps and 25 fps is not noticeable. However, you have to take care about the sound in that case.

Compare the running time of a movie you saw in the cinema with the running time of the same movie on a PAL-DVD. It is approximately 4% shorter on the DVD because it was shot at 24 fps and is now replayed at 25 fps. But you won't notice the difference.


Rob Lohman September 6th, 2004 03:26 AM

Another reason is that this would have been almost impossible
to implement technically due to the restrictions of the DV format.

And as Rainer indicated you really do not need it. If you really
care about film output talk to your film house and ask if they
need 25 fps for a european release or 24 fps.

Valeriu Campan September 6th, 2004 08:29 AM

I am aware that PAL requires 25p or 50i. Also I know that for theatrical release you can "sort of" get by adjusting the length/pitch of the soundtrack, but then why others bother - Sony, Panasonic, Panavision, Kinetta, Viper... making cameras with 24p option? And for the same reason, Arri Aaton, Moviecam should also drop the dreaded/useless 24fps and go 25fps.
Maybe Canon as always is ahead of the pack and we are witnessing the birth of a new standard?

Chris Hurd September 6th, 2004 08:52 AM

This standard is not new. Panasonic did it first, with their DVX100E having 25p instead of 24p, in the PAL model.

Who could tell the difference between 25p and 24p? Nobody; not humanly possible, so it's no big deal I think.

Barry Green September 6th, 2004 10:37 AM

24P is not useless, it's perfect for NTSC televisions (which make up about 70% of the TV's in the world).

25P is perfect for PAL television.

25P and 24P can be converted to each other with very little hassle.

Remember, these cameras (DVX and XL2) are not designed for film, they're designed to make video that looks like film, that plays back on an NTSC or PAL television. 24P is perfect for NTSC playback, since it emulates the look of 24fps film transferred to NTSC video. 25P works perfectly with PAL televisions.

Valeriu Campan September 6th, 2004 04:36 PM

Still I don't understand why the PAL users have to go through "the little hassle" of making their projects 24fps compatible for theatrical release. Looks like Canon decided to do a pre-emptive strike in the war against the 30% of the non-NTSC infidels.
The 24p option in the NTSC model is there solely for the possibility of using your project for theatrical release. Still, why higher end cameras from Sony, Panasonic, Panavision, Kinetta, Viper have the other options? Is it so expensive to implement it? I see it only as a software/firmware issue. Why denying the rest of us the same smooth passage, puzzles me.

I have recently shot a feature on 50i and the producer is in the process of preparing it for film conversion.

Don Berube September 6th, 2004 04:54 PM

Valeriu Campan writes:
>>>>>>>>Looks like Canon decided to do a pre-emptive strike in the war against the 30% of the non-NTSC infidels.

Eh,,, huh?

>>>>>>>>The 24p option in the NTSC model is there solely for the possibility of using your project for theatrical release.

Not 'solely' for that. It's also provided for those who will never do a film-out but want the motion signature of 24P.

>>>>>>>>Still, why higher end cameras from Sony, Panasonic, Panavision, Kinetta, Viper have the other options? Is it so expensive to implement it?

Exactly what options are you referring to?

>>>>>>>>I see it only as a software/firmware issue.

What exactly do you see as a software/ firmware issue? It would be helpful if you were to clarify your statements.

Why denying the rest of us the same smooth passage, puzzles me.

What exactly is it that you feel you are being denied?

- don

Thomas Smet September 6th, 2004 05:53 PM

us using NTSC still have to do a process to get 24p. The camera isn't actually putting 24p onto the tape but a 30i with 3-2 pulldown. Once we capture the footage we either have to convert the 30i with pulldown to full 24p or use an editing package that does it automatically for us.

NTSC- 30i with 3:2 pulldown frames - convert those frames to 24p
PAL - 25p frames - slow down to 24p.

When movies are shot in 24p they need to be converted in different ways to NTSC and PAL. For NTSC 24p uses a 3:2 pulldown method where you end up taking fields from different frames to get a pseudo 30 interlaced frames per second. For PAL the 24p movie needs to be sped up to make it 25p. The DVX and XL2 are basically doing the opposite of that process.

As for why do $100,000.00 cameras do this and not my $5,000.00 camera just think about it for a second. Do you really want to pay an extra 10 or 20 thousand for the XL2 to have advanced chips to allow you to shoot whatever frame rate you want? It takes a lot of hardware for those highend cameras to do that hence the higher price.

You know in some ways the PAL camera is actually better because you get a little more resolution per frame and you deal with full 25p frames from the begining instead of having to apply a reverse 3:2 pulldown. With the pulldown and NTSC if we shoot 24p video it will look kind of funky on TV's. With 25p it will always look goof no matter how you shoot or what format you view it on. The only downside to 25p is having to slow down the audio by 4%. If you don't want the slight pitch change you could always time compress the audio.

Finally if you only plan on shooting movies with your XL2 why not get a NTSC model and a cheap power converter? That way you can have 24p. You could always get 25p if you really needed to also. You would just do the opposite and speed up your 24p video to get 25p to view on your TV.

Valeriu Campan September 7th, 2004 03:12 AM

<<<-- Originally posted by Thomas Smet :

As for why do $100,000.00 cameras do this and not my $5,000.00 camera just think about it for a second. Do you really want to pay an extra 10 or 20 thousand for the XL2 to have advanced chips to allow you to shoot whatever frame rate you want? It takes a lot of hardware for those highend cameras to do that hence the higher price.. -->>>

The NTSC model doesn't seem to cost extra 15-20k with those advanced chips to have that third extra option. Just machining and manufacturing a different shell for the PAL camera and a switch seemed to be more cost effective for the bean counters.

Having said that, for my next major project, a PAL XL2 has already been ordered (a dumbed down PAL model... huh...) and I feel that a second one will be on the cards for safety/backup reasons. By the way I will sell my original XL1 (PAL). Any takers out there??? Hard to believe!

Rob Lohman September 7th, 2004 06:04 AM

As I stated earlier Valeriu, the DV specifications DO NOT allow
for the format you are describing, nor does any NLE have a
template / profile for it. So it's not "just" Canon's decision.
I don't know of any PAL camera that "has" 24p.

So I assume you would want this PAL 24p for the benefit of
the higher resolution to go out to film? Will you really be going
to film?

Martin Munthe September 7th, 2004 08:11 AM

<<<-- Originally posted by Valeriu Campan : Still I don't understand why the PAL users have to go through "the little hassle" of making their projects 24fps compatible for theatrical release. -->>>

Since every post house in the PAL world is set up to handle everything at 25fps (with pitch conversion on optical prints being a standard process done in the print process or the "film out" process) it's a MAJOR hassle to shoot 24fps and expect it to be a smooth workflow. In europe almost everything is shot 25fps. That includes 16mm and 35mm. It's so much easier to handle 25/50 based projects in the postproduction process. I bet a lot of americans would LOVE to not have to go through the 2:3:3:2 pulldown everytime they make something for the big screen. It's so awkward. The best thing would to let go of the old analog 24fps standard and just shoot 25p, 30p and 50/60p. It saves time and money.

I was talking to the matchcutters and tech people at Technicolor and Manhattan Transfer, New York (they did 25fps dailies for us on a 35mm shoot) and they where so envious of the simplicity of the PAL 25fps/50i setup.

Rob Lohman September 7th, 2004 08:32 AM

Martin: I totally agree. I think Valeriu is just wanting a higher
resolution at 24 (native) fps. Probably not aware of how much
"work" the pulldown process is in the XL2 24p mode for example
(speculation).

Thomas Smet September 7th, 2004 10:11 PM

you are not understanding the process of creating 24p on these cameras. No the NTSC doesn't cost an extra 20 thousand. The point we are making is that in order to get a camera that can do 24p, 25p, 30p, 60p, and 60i you have to have some advanced chips that cost a lot. For NTSC we are fortunate that there is a process to calculate 24p from 30. The camera isn't actually shooting 24p in NTSC. It is shooting 30i that is in a slightly different field format so when we apply a 3:2 pulldown we get a pure 24p. For PAL there is a different process to get to 24p. This isn't Canon's or Panasonic's fault. Blame the people who decided to make these video standards 50 years ago. The SONY Cinealta camera has chips that can do every format because it was designed to and costs a lot more to do.

What format would you rather have Canon and Panasonic use?

Clearly 25p Pal cameras cannot use 3:2 pulldown because then you would have 20P which would not be any use to anybody. If 3:2 pulldown doesn't work then what is there to use for PAL?

You have basically two options for PAL cameras.

1. Slow it down by 4% which would not be able to be done while shooting live.

2. Have advanced chips and camera design that could basically process video live at any framerate. Very expensive.

You can see why to get 24P in PAL it would be very hard and expensive. I'm sorry that is the way it is. I wish there wasn't PAL and NTSC but there is and we have to deal with it. Lucky for us NTSC users there is a hack work around to get 24P live.

David Lach September 7th, 2004 10:27 PM

I don't understand what you're saying Thomas. You can't get a "pure" 24p out of 3:2 pulldown. 3:2 pulldown means there is frame alterations because of the way fields are (re) combined that cannot be recovered without recompression.

The Xl2 and DVX100A NTSC do sample 24 (23.976) progressive frames a second, the pulldown is added after to be able to recover the footage in true 24p. That's why you have the 2:3:3:2 pulldown. So you can just discard the extra "fake" frame created by the camera to comply with NTSC 60i. That's also why you can shoot using a 1/48th shutter speed.

So unless I'm not getting your point when you're saying "For NTSC we are fortunate that there is a process to calculate 24p from 30. The camera isn't actually shooting 24p in NTSC. It is shooting 30i that is in a slightly different field format so when we apply a 3:2 pulldown we get a pure 24p" I think this isn't accurate.

Thomas Smet September 8th, 2004 02:07 AM

my point is on tape it is 30i. You cannot get 24p onto DV tape without using a different format such as HDV. When you capture your footage it needs the pulldown unless you have a program that captures it as 24P. Yes the chips and shutter speed are at 24 or 48 fps. The raw data is captured at 24p. For NTSC it is then fairly easy to deal with. The camera can then just add a 3:2 pulldown to the 24p raw frames from the ccd and we now have 24p footage that fits inside the NTSC standard. For PAL however what are they supposed to do to get 24P onto a 25P tape? There is no easy formula to do this. The camera cannot do any timeshifts live so this is out of the question.

The fact is that it is much easier to get 24 from 30 then it is to get 24 from 25. A pulldown system cannot be used with PAL video unless you want 20 frames per second video.

30 / 1.25 = 24fps
25 / 1.25 = 20fps *

*if the same 3:2 pulldown system is used.

Rob Lohman September 8th, 2004 02:20 AM

The XL2 will indeed sample at 24p and then create 60i/30p from
that. Which is completely reversable without any loss.

In theory the easiest way to do 24p in 25p is simply duplicate
one frame every second. When editing etc. you can simply
remove this duplicate frame. This would be quite easy to
implement on both a camera and an editing application. The
only problems are:

1) there is no standard for this (so no-one supports such a system)

2) I'm not sure who would actually use such system. I doubt there would be enough of these people to warrant a new standard that camera manufacturers and NLE makers will support

David Lach September 8th, 2004 08:39 AM

<<<-- 2) I'm not sure who would actually use such system. I doubt there would be enough of these people to warrant a new standard that camera manufacturers and NLE makers will support -->>>

Nobody would use it. The fact remains, even though it can be time consuming because of the software processing involved, converting progressive PAL to NTSC is an easy process. it works with the same 3:2 pulldown principle. Film transfer is even easier. All you need to do is slow it down by 4%. The difference isn't noticeable. Tranfer houses will often do it for you with not additional fee involved.

Every day I wake up wishing we had PAL here in Canada and the US for the higher resolution and closer to film frame rate, but it isn't the case, so we need to live with it. PAL countries are fortunate enough to be able to do everything in 25p. We don't have such an option in NTSC world. Therefore it's important to have a 24p option. It is not important however for PAL camcorders and this is actually the first time I hear someone complaining there isn't a 24p option on a PAL model.

Rainer Hoffmann September 8th, 2004 09:35 AM

David,

many people over here in Europe envy you guys in Canada or the US because, so they tell us, you will be having HDTV in a few years. In Europe we hardly know what HDTV means. We will be stuck with PAL for quite some time, it seems. Then again, it means that the XL2 I'm gonna buy in the near future will not be a heap of scrap metal in a matter of 24 month.

Barry Green September 8th, 2004 10:10 AM

Quote:

The XL2 will indeed sample at 24p and then create 60i/30p from that. Which is completely reversable without any loss.
??? Not sure what you mean here by 24P creating 30P. The XL2 CCD's run at three different scanning rates: 24 frames per second, 30 frames per second, and 60 fields per second. Each of those frame rates can get recorded on the 60i tape format and be reconstructed to its original form.

Quote:

In theory the easiest way to do 24p in 25p is simply duplicate one frame every second. When editing etc. you can simply remove this duplicate frame. This would be quite easy to
implement on both a camera and an editing application.
There are a couple of different approaches to this. Sony, when developing their 24Psf method, apparently just runs the tape a little faster when recording, so they spread 48 fields ("segmented frames," as they call it) across the same tape space that 50i would take up.

In telecine conversions, sometimes they will do what you say, dupllicating a frame, although when going to PAL they will split that frame to make the duplicated frame a little smoother (i.e., one field from the previous frame and one field from the next frame).

But mostly, they do a frame-for-frame transfer, and then just adjust the runtime and the audio to compensate. So 24P gets transferred frame-for-frame to 25P, which means that the program will run about 4% shorter in PAL land, so you have to re-pitch the audio half a semitone lower to keep the same pitch.

Camcorders do exist that do what's being talked about here: 24P/25P/30P/50i/60i, but they aren't cheap... the Sony CineAlta does all those frame rates, but of course it's around $100,000.

David Lach September 8th, 2004 08:35 PM

<<<-- Originally posted by Rainer Hoffmann : David,

many people over here in Europe envy you guys in Canada or the US because, so they tell us, you will be having HDTV in a few years. In Europe we hardly know what HDTV means. -->>>

Well I'd definitelly be happier with a 25p/50i higher resolution system here in North America. I guess the grass' always greener on the other side of the fence... ;)

Rob Lohman September 9th, 2004 02:37 AM

Quote:

Quote:

The XL2 will indeed sample at 24p and then create 60i/30p from that. Which is completely reversable without any loss.
??? Not sure what you mean here by 24P creating 30P. The XL2 CCD's run at three different scanning rates: 24 frames per second, 30 frames per second, and 60 fields per second. Each of those frame rates can get recorded on the 60i tape format and be reconstructed to its original form.
What I mean is that the 24p signal coming from the CCD's is
pulldown-ed to 60i/30p before it is layed down to tape. Since
the DV spec does NOT allow for 24p to be stored as is on tape.

The NLE (when it supports it) does an inverse pulldown to get
the original 24fps from the 60i/30p footage. This is well known.

The reason I mentioned this (again) was to illustrate that they
are already working around the DV spec and supporting some-
thing like 24p in a PAL camera would require more work arounds.

Barry Green September 9th, 2004 11:21 AM

Okay, just making it clear... I've seen many threads where people claim that 24P isn't "really" 24P because it gets converted to 60i, and that's just silly, of course. The cameras DO capture 24 frames per second, and they render motion identically to how a film camera does.

The terminology you used had me confused, when you said that 30P gets created from 24P. 30P is unrelated to 24P of course, and the CCD actually runs at the 30-frame-progressive scan rate to create the 30P sequence.

Chris Hurd September 9th, 2004 12:32 PM

Thanks Barry, and let's all please remember that what happens in the camera head is a different thing than what happens in the tape transport. The 24P mode produces the temporal motion of 24 frames per second; maybe the tape transport can't tell the difference but our eyes can. Think of it in the same way as progessive vs. interlace: progressive video is recorded to tape as interlace, except the two separate fields are no longer 1/60th of a second apart (okay, 1/50th for you PAL folks). Does it LOOK like interlace? Heck no, it looks like progessive because that's what it is in the camera head. Just like 24P looks like 24P, because it is 24P, forget about how the tape transport writes it (the only real question is which method you want, 2:3 vs. 2:3:3:2).


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