Does Anyone know the "Rules" for Slow-Mo-ing a 25p PAL footage?!?Plz help! [+twixtor]

E

eladbari

Member
Does Anyone know the "Rules" for Slow-Mo-ing a 25p PAL footage?!?Plz help! [+twixtor]

Hey Guys :]
i need your kind help, fast, as im shooting pretty soon! [p.s-tried the search...]
Ill make it short.

I wanna make a video clip, all made out of slow-mo shots.
I have the Barry Green book, but it only give directions to NTSC users, But not to PAL users.
What i wanna know is:

1.what do i need to set the camera on, while shooting with the DVX100A? [50i? 25p? , any shutter speed setting? etc.]
2.what manipulation do i have to do in post for the material? [slow it by 50%? more? less?], so its as smooth as possible?

keep in mind, i want the final "product" to have the progressive [25p] look!

ive heared about twixtor.
If i use it, then how it will effect question number 1+2?
does anyone have a link to a [video] tutorial for this specific plug-in?

Thank you SO MUCH, Guys !!! :]

elad.
 
You definately want to shoot 50i for any slow motion shots. I don't know twixtor. But in after effects (probably the same principle) If you slow 50i down by 50% it becomes 25P with a slight loss of resolution. If you slow it any more say 25% then the program needs to put intermediate frames in so you still have 25fps and not 12.5 fps. Do a search for slow motion on this website, there are tons of tutorials.
 
thanx for the comment, Kdawg! :]
I gotta say, ive tried doing that....taking a 50i footage, and slowing it down by 50%, but it all came out not so smooth. [plus i think i had some interlacing lines issue or something]. Although i think ive slowmoed that test-footage using Premiere, and not while in After-Effects.
are u sure that slowing by 50% makes a footage turn from interlaced [50i] to progressive [=25p] automatically? seems kinda weird.

tried to find some tutorials, but they all refer to 24p NTSC, and not 25p.... :\
 
Hmm well with 60i editing it in 30 fps timeline, it comes out smooth (30 half fields). It would seem that 50i and 25P would divide up in the same manner. However, here is what After Effects 6.5 does with frame blending fields on 30P footage. This was shot 30P and slowed to 50%. Download the file to see in full quality.
 
a little step...

a little step...

thanx for the replies guys :]
Kdawg...your link for the video sample doesnt work [moive is missing\gives me errors from fileplanet while downloading]. :\

Milleto, thanx for the link! that site looks really nice...ill dig into it! But the sample link only gives me a "feeling" of what to do..and not specific directions, since i dont mess round with 24\30 timeline...but 25...
it seems like most of the community is filled with NTSC users, and i totally understand it. i just hope it was a little more balanced..
although i believe there are more "issues" with NTSC and PAL while editing... [thats the sense i get :]




been messing round with Twixtor. its not an easy plugin to mess with...
but ive managed to slow down this clip that was shot @25p...by 50% ..and it came out kinda nice. pretty smooth. but i noticed that the edges are going crazy when i move the camera a little bit. theres noise coming there...
it seems that the picture is slightly smoother...not as sharp as the original..and i hope its not gonna be an issue, while switching to Slowmo shots...[=wont be noticable].
still...this seems like a "last minute" fix around...but im not satisfied with it.. i would really like to get to know this plugin better [the official tutorials of twixtor arent that great in my opinion]. or maybe there are other good methods for slowmo out there?
though i believe that Twixtor saves my ass, as what im really afraid of, is that i will lose my 25p [progressive] look, while taping in 50i [interlaced]. slowing down an interlaced shot, wont give me the same "look" and "feel" of a progressive shot. plus, id have to switch from 25p to 50i while shooting?! and know at advanced-what slo mo shots i wanna have? ...thats kinda weird... [though maybe my "workflow" understanding is the problem here :]
 
What I have found out to be the smoothest slow-mo with pal dvx, is to shoot 50i with shutter speed 1/120. And then you import the footage in After effects first and use "time-stretch"(under Layers menu) and type in 200%. Make sure that all motion blur and frame blending is turned OFF before rendering out the clip. THis should give a nice 50% slowmo.
Here's the guide I use(Though it reffers to ntsc): http://rarevision.com/v1/articles/slow_motion.php

And here's a sample of mine were I used that technic:
http://www.rimeligok.no/anders/Espen/Espen.mov

Good luck :)
 
Hey there Smettli!
I LOVED your movie sample! The slowmo, the DOF, the feel of it....everything! :] [just the crossfades werent in place imho].

a few questions:
1.What camera u used there? HVX200?
2.When u know you wanna shoot slowmo-do u shoot all the material @ 50i? or u switch between it to 25p?
3.how do you still get that progressive "feel" to your video? ive tried slowing down 50i footage, and it didnt keep the progressive "look" & "feel".
[u think its the shutter speed thing?].

Gotta say, i CANT believe that was PAL footage!
It looked like NTSC...and why do i say that? because i sadly believe that the 1 frame difference between 24p to 25p - does a LOT. and so when i shoot stuff, it never comes close to the "look" and "feel" of videos i see that were shot in the U.S [its less "stuttering"].
this is so weird...yet....u know...film is 24p...and not 25p...so... :\
 
Smettli is right on the money but here's another way you can do it...
Shoot your footage 50i on the DVX but change the shutter speed. Smettli said 1/120 which works nicely although it should really be 1/100 but the DVX-100 first version doesn't have this shutter speed in the presets.
(NTSC = 60i 1/120) (PAL = 50i 1/100)
Capture/dump your DV footage as you would normally do onto your computer ready for editing.
Now what you want to do is create a PAL workspace like you would normally do for DV but use the setting 25P or "Frames Per Second" = 25 & "Field Order" = Progressive.
Import or open your footage into this 25P workspace and drop it onto the timeline. In the "Clip" or "Properties" section change the "Speed" to 50% and make sure you also select the processing option to "Deinterlace Under 100%" (this option may be worded differently in each program or may not exist), so basically deinterlace the output.
When you play your clip in the timeline you will have nice smooth slow motion. The only real thing to keep in mind is that your footage is now technically half the vertical resolution but a lot of the time it's not visible unless your playback screen is very large. I use Canopus Edius 4 and have found it very easy to work with and produces good results.
You can see a short "DVX Slow Motion Demo" I made on youtube using the above specs but in this clip the speed is actually 1/4 of original or 25% speed. If you look into the working principles of this process it's really only designed to work at 50% of the original recorded speed and no other but as you can see it is still very effecting even down to 25%
Hope this info is of some value to you :)

My Youtube Slo-Mo DVX Demo = http://www.youtube.com/watch?v=nSdC6L9OHio
PS. Remember that youtube video is not that great so the picture quality is degraded compared to the original
 
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I shoot with a dvx PAL, and I plan to shoot slomo when I shoot at 50i with 1/120.
Even though the correct shutter number should be 1/100, I find that to become to motion blurry(seen it done with the canon xh a1), so 1/120 shutter is perfect for me.
After you shoot 50i, 1/120 shutter, it's important that you bring the footage into after effects, and before adding the clip to the composition you right-click the clip and choose "interpret media -> main.." where you check the "conform framerate to 25fps" and make sure "fields" are set to "lower field first" and check the box "Preserve fine edges" within the "interpret media window-menu. Then you add the clip to the composition and use the time-stretch(200%) under "layers"-menu, and not just slow it down in premiere. The reason for that is that aAter effects de-interlaces the footage creating to frames of each interlaced frames, and that is why the resolution also gets lower in each frame after the process.
But it's really easy and fast to do, and works like a charm everytime :)
 
I must try out Smettli's way to make slo mo as it is a different process to what I said. Actually, it's probably going to be somewhat different for every program but it may be worth one day trying the various NLE progs to see what result you like the best...
When you finish your video it would be sweet if you could post a link so we can check it out... Good luck :)
 
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