DVX 100b 24 progressive advanced

[Brian Babarik]

I was speaking with an editor who said that there is a Panasonic camera that shoots is a 24P mode and has a final output of 29.97. I checked the manual for the DVX and it says that the video signal recorded is 525i (NTSC) using the 60i option and in progressive mode to convert to 525i and record. I shot 24P advanced with the DVX 100b last week and the editor says the footage looks best when captured into Final Cut using the 29.97 preset. I do not believe they captured using the advanced pull-down option from Final Cut yet but am wondering - Does anyone know whether or not the DVX 100b or any other Panasonic camera converts 24P to a 29.97 signal? Do all cameras use this conversion for viewing or editing? I'm sure I'm missing something but I don't know what. Any help would be greatly appreciated. Thank you much.

[Daniel Sheehy]

24P to 29.97..? The camera is either native 50i or 60i driven. That can then be recorded as 24P with a 2:3 pulldown, or 24Padvanced with a 2:3:3:2 pulldown. In both cases, the conversion is to 24fps, rather than from.

 

So no, the DVX cameras do not convert 24 to 29.97... rather, the conversion is always from 60i or 50i to some sort of 24P, or 30P frame rate. I can't however speak for other Panasonic cameras...

 

Having said that, the output can be captured to a 29.97 timeline, but the conversion is handled by the NLE software, rather than the camera.

 

And... before too long, someone is going to jump in here and tell you that you have to go to 'My Controls' and do something to that username of yours...

A real name is requested... just giving you a heads-up. :)

[Gordon Highland]

Yes, 29.97 interlace is always what's recorded on the tape itself, and thus it can be captured this way also and edited accordingly with no additional rendering if you want. And it has that same strobey film look that comes with pulldown. The additional frames are removed during capture (if you choose, and if you're using "advanced" pulldown) to get to 24 progressive. The SDX is the same way.

[David Mullen ASC]

The camera always records 29.97 fps / 59.94 fields per second if you get the NTSC version. When in 24P mode, you are shooting at 23.976 fps actually and recording to 59.94i with a pulldown, two types possible: standard and Advanced.

 

If you get the PAL version, it always records 25 fps / 50 fields per second -- but 24P is not an option, only 25P. And there's no pulldown needed or used.

 

You do have the option of removing the pulldown in order to edit in 24P. With the Advanced pulldown, some NLE software can remove it when importing the footage. Standard pulldown requires you use the "reverse telecine" feature in the NLE software to remove.

 

If you leave the pulldown in and edit the material as 59.94i, then the pulldown cadence will be disrupted and hard to remove later. Since the Advanced pulldown is actually a cruder and more visible scheme, since it was only meant to be used for removing it easily, then the worst thing is to shoot with Advanced pulldown and then never remove it and cut it as 59.94i. Then you are more likely to see that pulldown "hiccup" in motion now and then.

 

Actually, Daniel, the DVX100 does convert 24P capture to 60i (23.976 to 59.94) for recording. It has a progressive-scan sensor, unlike some other cameras.

 

And yes, "babarik27" needs to go to My Controls and edit his or her Display Name to a real first and last name.

[Brian Babarik]

Thanks everyone. I think I've now wrapped my head around this. I also changed the screen name and apologize about not doing that sooner. Thanks again.

[Daniel Sheehy]

Actually, Daniel...

You are indeed right, I stand corrected.

 

http://www.adamwilt.com/24p/

[Phillip Evanesce]

You do have the option of removing the pulldown in order to edit in 24P. With the Advanced pulldown, some NLE software can remove it when importing the footage. Standard pulldown requires you use the "reverse telecine" feature in the NLE software to remove.

 

If you leave the pulldown in and edit the material as 59.94i, then the pulldown cadence will be disrupted and hard to remove later. Since the Advanced pulldown is actually a cruder and more visible scheme, since it was only meant to be used for removing it easily, then the worst thing is to shoot with Advanced pulldown and then never remove it and cut it as 59.94i. Then you are more likely to see that pulldown "hiccup" in motion now and then.

 

I'll try to phrase this question semi competently, but please forgive me if I screw it up. I am pretty new at this. I think I understand the difference between 24p and 24pa, sort of. And I know that Vegas 7 will do the pulldwn so that I can edit in 24p or 23.976p, so I'm not worried about that.

 

Here is my question (scenario): I want to shot 24pa to get the film look and also preserve optimal data. I am planning on rendering out for DVD, but I would also like the option of doing a film-out if the opportunity arises. I also want to intercut stock and historical footage into the timeline, some of which wasn't shot in 24p or pa. As I understand it, if I shoot in 24p, I can edit in a 29.97p timeline, which wouldn't affect the stock footage, but If I pull that non-24pa footage into the 23.976p timelime, I could get some noticeable motion artifacts. Is this true, and what is the best way to handle these scenarios?

 

I hope some of that made sense.

[David Mullen ASC]

People use the term "24P" out of habit, but it's actually 23.98P (or 23.976 actually). The only question is what sort of pulldown are you selecting to record it to NTSC (59.94i / 29.97 fps) and if you are removing the pulldown before cutting in order to be cutting original frames at 23.98P.

 

Because if you cut pulldown material at 59.94i / 29.97 fps, then your pulldown sequence/cadence will be broken-up and hard to remove after the fact in order to get back to the original progressive-scan frames.

 

As for adding archive material that is 59.94i, it's a problem -- I suppose the safest solution would be to convert it to 23.98P first before you cut it into your project.

[Michael Nash]

Here is my question (scenario): I want to shot 24pa to get the film look and also preserve optimal data. I am planning on rendering out for DVD, but I would also like the option of doing a film-out if the opportunity arises. I also want to intercut stock and historical footage into the timeline, some of which wasn't shot in 24p or pa. As I understand it, if I shoot in 24p, I can edit in a 29.97p timeline, which wouldn't affect the stock footage, but If I pull that non-24pa footage into the 23.976p timelime, I could get some noticeable motion artifacts. Is this true, and what is the best way to handle these scenarios?

 

You don't want to create a 30p (29.97p) timeline if you ever want to go back to 24fps film, it will give you the MOST motion artifacts. You'd want either 24p or 60i, depending on the source material.

 

The simplest approach is to just create a 60i timeline, shoot your new material in 24p (not "a"), burn your DVD as 60i and be done with it. If you ever really do need to do a film-out you can go back and try to sort out the pulldown and cadence for *each* shot later, to create a 24p master.

 

If you're determined to create a 24p timeline, then you'll need to convert your stock footage to 24p first. That means 60i-originated material will have to be converted to 24p, and any 60i footage from 24fps sources (film transfers or 24p video) will have to have a reverse-pulldown applied to get it back to 24p. Once everything is 24p, you can spit out both 60i and 24p sequences.

 

So if you KNOW you're going to going to edit in 24p, then you'd probably want to shoot in 24p"a" and remove the pulldown during ingest. If you're not sure, you could shoot 24p and perform a reverse-pulldown later if you have to.

[Phillip Evanesce]

If you're determined to create a 24p timeline, then you'll need to convert your stock footage to 24p first.

 

Other than better frame recovery, is there really any advantage to shooting in 24pa?

[Michael Nash]

Other than better frame recovery, is there really any advantage to shooting in 24pa?

 

AFAIK, 24pa is there soley for NLE's to be able to quickly and easily remove the camera-added pulldown to create a 24P file (if that's what you meant by "frame recovery"). It's just an option that Panasonic came up with (or whoever invented it) as an alternative to render-based pulldown removal.

 

Personally I can see the unusual cadence when displayed on 60i and find it distracting, so I avoid it unless I know the footage will be ingested as true 24P. Some people don't seem to mind it as much.

[David Mullen ASC]

http://www.adamwilt.com/24p/index.html#When_to_shoot

 

But 24p Advanced isn't intended for making the 60i video look like film; it's designed to allow the best possible recovery of the original 24 frames. You'll note that all four original frames can be recovered from self-contained 60i frames; the green frame in 60i now contains the "extra" B and C fields and can be discarded, since all the information for B is contained in the yellow frame, and all the information for C is in the magenta frame.

 

Extracting a true 24p clip from a 60i recording simply requires copying the raw data for the red, yellow, magenta, and blue frames into a new 24p file, skipping the green frame altogether. No decompression or recompression is required, and all recovered 24p frames retain first-generation quality. No clipping or other loss is incurred; you are still working with all your frames in their first-generation glory in 24p.

[Phil Rhodes]

I think the main reason they came up with it, other than a sincere and understandable desire to avoid recompression, is that DVSD is a frame-based rather than a field-based codec and only encodes fields if it sees enough HF detail vertically to make it worthwhile. This can, at least very very subtly, blur things together rather.

 

Phil