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

Pete Bauer August 28th, 2005 06:26 AM

Hi Bill,

I'm guessing that your final product will be a DVD? If so, it really is entirely an artistic choice, since the DVD will yield an NTSC standard signal and the TV will be able to play it. People like 24p for its film-like appearance (if it is done properly, of course) AND it allows about 20% more material to fit on a DVD. Using 60i tends to give more the fast-action video look -- great for your kid's ball games, etc.

On DVD, 60i is simple...29.97 frames/second, each of two fields. In 24p, flags are added to tell the DVD player what fields to repeat to reconstruct a 60i NTSC signal with the ol' 2:3 pull-down scheme to give the film-look. This Vegas document describes the DVD workflow (which will be similar in other editing and authoring apps for any camera using Panasonic's 24pA scheme, which includes the XL2) starting on page 7:

http://mediasoftware.sonypictures.co...ctinfo/24p.pdf

It is a quick read and well worth it for anyone doing 24fps work with just about any software or DV camera.

Laurence Kingston August 29th, 2005 04:41 PM

Remember that each format has it's advantages and disadvantages:

24P: Better resolution on each frame. Not as good for fast motion, quick pans or zooms though and hand held camera shake looks jarring. Also, autofocus takes about 4 times longer to focus. Footage can't be slowed down for slow motion effect (though you can temporarily go back to 60i for shots you know are going to be slowed down). Really the best choice if you are doing movie style camera work with lights, tripods, dolly shots and good looking talent.

60i: Half the resolution on each frame, but twice as many of them. Still the best thing for run and gun work. Fast pans and zooms look smoother and handheld camera work isn't nearly as jarring. Brighter image in low light. A much more forgiving format. Not as pretty though.

Marlon Torres August 30th, 2005 11:19 PM

Mixing 60i with 24p
 
Is it to okay to mix up 60i footage with 24p footage on premiere pro? basically i want to shoot footage that will be in slow mo in 60i because it has more frames but non-slow mo footage will be 24p

Pete Bauer August 31st, 2005 12:36 AM

Kind of surprising, but from the lack of response to a very similar question the other day in the Premiere forum, there seems to be not a lot of experience with that:

http://www.dvinfo.net/conf/showthread.php?t=50068

Since your question is so similar to Marc's, let's use that existing thread to continue the discussion, and hopefully we can compile more info on this subject in the near future.

Ryan Graham August 31st, 2005 09:13 AM

I've been inserting 24p footage into 60i sequences lately, and Premiere seems to handle that fine. I used the default 60i NTSC preset for the project. It appears to add some sort pulldown to the 24p footage, so you end up having to render the 24p footage to preview it properly on an NTSC monitor. But other than that, I haven't seen any problems.

I haven't tried it the other way around, however (inserting 60i footage into a 24p sequence). I'd assume in that case that Premiere would automatically try to convert the 60i footage to 24p, dropping frames in the process. Converting 60i footage to 24p in order to do slow motion is something that would best be done by Twixtor in After Effects. I use Magic Bullet to do a film-look conversion from 60i to 24p (non slo-mo), and I know for a fact that there is nothing in Premiere that can do anything like that.

For what it's worth, I've been mixing footage in order to trim down a feature length film I'm working on. I have scenes that have been edited in Premiere and then color corrected and converted to 24p in After Effects. Unfortunately, my film is too long right now (over 2 hours) and I need to chop stuff out. And since there is no way to "refresh" a project in After Effects (i.e., when something changes in the Premiere project, it also changes in the associated After Effects project), I just have to cut down the final renders in Premiere.

So I'll stick a 24P render back into its original 60i timeline, on an upper Video track, and then trim all tracks at once when cutting out shots or sections of a scene. After that, I export the audio to Sonar via Automatic Duck's new PPro Export (a great plugin which I beta tested for, and that I probably couldn't live without now) for final audio mixing, mastering, and export to a wav file.

After all of that, I create a new 24p project, and just copy and paste the re-edited 24p tracks from the 60i sequences into the 24p timeline. I then add the mastered wav files in, line them up with the start of each scene, and then export out the whole thing to a 24p mpeg2 for DVD authoring.

It seems complicated, but it works out pretty well. I wish After Effects would pick up on changes made in imported Premiere sequences, though. That would make things much easier.

Ryan

Eric Brown August 31st, 2005 10:35 AM

Okay, found it in another thread

http://rarevision.com/articles/slow_motion.php#

Eric Brown August 31st, 2005 10:36 AM

Ooops. Sorry if I'm cross-posting, Chris.

Eric Brown August 31st, 2005 04:06 PM

Little late coming into this...I use my first gen' Optura for capture, basically a mini DV deck. My XL2 never gets hooked up to my computer as I have no need.
I've been using the same brand tapes in both, Panasonic AY-DVM63MQ, and haven't had an ounce of trouble from either camera or Final Cut Pro.

Jimmy McKenzie August 31st, 2005 08:03 PM

Hi Cory, I hope the above has helped. I don't want to hijack your thread, but my original related post went unanswered and perhaps these kind gents above might be able to assist:

http://www.dvinfo.net/conf/showthread.php?t=49848

Thanks to any who might have a chance to inspect the above.

A. J. deLange September 1st, 2005 01:01 PM

There are two issues here: crossplay and pulldown. "Crossplay" is the ability to play a tape on any machine which adheres to the same standard (in this case DV) as the machine on which it was recorded. Unfortunately I have seen several reports of inability to play back tapes recorded on XL cameras on other DV machines. If it's any solace decks, as opposed to cameras, seem to be able to tolerate more latitude.

Independent of crossplay is pulldown. This is not a problem between machines as long as crossplay is working OK. It has already been mentioned that the camera video output is 60i irrespective of the mode of recording. In 24p the camera records 24 frames in a second. Call these A, B, C, D and so on. For recording these frames are separated into interlaced fields i.e. A1, A2, B1, B2, C1, C2, D1, D2 and so on with A1 being the first field of the first frame, A2 the second field of the first frame, B1 the second field of the second frame ... These are written to tape at 60 fields (30 frames) per second thus: A1A2, B1B2, B2C1, C1C2, D1D2. Thus four out of every 5 frames contain fields from the same camera frames but the one in the middle contains fields from two camera frames. The results of this are that frames A and B which were taken 1/24th of a second apart are shown 1/30th of a second apart and B and C, also taken 1/24th of a second apart, are displayed 1/15th of a second apart with a mix of B and C shown in between. This results in a somewhat jerky playback particularly in the mixed frame if there was motion between B and C (an object and its "ghost" may be seen simultaneously). On average, though, 24 frames per second are displayed. Because of this jerkiness there is little reason to use 24p unless you need to get eventually to a 24p medium i.e. film. When you do that you need capture hardware/software that takes the first and second frames off the tape, throws away the third frame, then captures the fourth and fifth frames and repeats this pattern. Such a system captures A1A2, B1B2, C1C2,D1D2,E1E2... i.e. the frames taken by the camera. (Note: actual frame rates are 30/1.001 and 24/1.001. Also note that I don't know which fields are used in the mixed frame so I guessed B2C1 which seems reasonable but I don't know that it's not actually B1C2 or even C2B1 for that matter.)

Marlon Torres September 8th, 2005 10:39 PM

my 24p doesnt look right
 
24p is supposed to look like film right? well i shot some 24p footage today and i dont know about you but this doesnt look like 24p to me... it looks like its doubling frames or something...any suggestions?

http://www.marlontorres.com/films/24p.mov

Rob Lohman September 9th, 2005 01:35 AM

It looks okay to me. Keep in mind that 24 fps (especially progressive) footage
is inherently more "skippy". Especially compares to 30 fps interlaced. At what
shutter speed where you shooting? 1/48th is a good number to use with 24 fps.

You carefully need to think about motion in 24p. Especially pans and things
like that. Another reason to compose "elegant" moves. If you are going to
shoot high speed action it may be wise to move to 30p or 30i and then slow
that down (go to 24p)for example (better with 30i).

Ash Greyson September 9th, 2005 01:39 AM

Were you in 24P or 24PA? Looks more like 2:3:3:2 pulldown or 24PA. Either way, your footage is perfectly normal. 24P exhibits similar motion as film but in no other way makes video look like film. 24P IS AN EFFECT, it is NOT I repeat NOT a way to make your video look like film. I have this fight over and over with people and I shoot 24P quite a bit but it must be MOTIVATED like any other effect.

You can argue all day about the technical aspect but 24P video does not look to the eye the same as 24P film when both are pulled down to 60i. Most the differences come from the way the source is shot. DP's on film know the limitations of 24P and how fast they can make moves, etc. IMHO, 24P video is best for slow cinematic moves or environments were you will have a shallow DOF. It CAN help you achieve a film like look but it does not in any way shape or form make up for inferior operation or production values.



ash =o)

Richard Hunter September 9th, 2005 03:10 AM

Hi Marlon. You can play around with the shutter speed to trade off motion blur against strobing, but basically, 24p is like this. If you don't like the effect you either have to avoid this type of action and movement, as Ash mentions, or else capture more images per second i.e. shoot 30p or 60i.

Richard

Bruce S. Yarock September 9th, 2005 05:15 AM

Rob,
You mention "30p and 30i". I thought that there is only one '30" setting on the xl2.
Bruce Yarock


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