Overcranking / Slow motion techniques with the XH A1

[Christopher Warwick]

When I came to decide on which camera to buy, the fact I couldn't overcrank the A1 was at the top of my 'cons' list. It almost tipped me over to buy the EX1 instead. I'm sure Canon have lost custom due to this. Anyone know why Canon didn't bother including this function?

Anyway, I was wondering what experienced A1 owners do to achieve slo mo effects. I wouldn't have thought shooting at 24 fps and using software such as Twixtor could achieve effective results (although I haven't used the software myself, so I can't say for sure).

I'm really impressed with results like this Letus Extreme Nature Short - Misty Brook - HDTV on Vimeo on the EX1. Could the same quality be achievable on the XH A1 do you think?

Perhaps software like Twixtor can achieve fine results in slow moving footage, but fast action might pose a problem.

Chris

[Joe Busch]

Any camera shooting 60i can make 60p esq slow motion with Vegas quite easily.

http://www.youtube.com/watch?v=cU-gIXRcBR8&fmt=22 Youtube Hd or...
http://lousyhero.com/videos/epicprev2hd.wmv 1080p... HD

Simple example, all that was shot with a little HDR-FX7 which is only capable of 1080i60... :D

That video does make me want a letus though... hah...

[Bruce S. Yarock]

Do you need to shoot in 60 for good slow motion on the A1? What if you shoot in 24 and jack up the shutter speed?
Bruce Yarock
Yarock Video and Photo

[Christopher Warwick]

Originally Posted by Bruce S. Yarock

Do you need to shoot in 60 for good slow motion on the A1? What if you shoot in 24 and jack up the shutter speed?
Bruce Yarock
Yarock Video and Photo

I haven't bought my Letus adapter yet, but they say fast shutter speed on the extreme/elite is a big no no. It's why I'm holding off investing in it until I can see what is achievable for the elite vs the ultimate (in terms of fast shutter speed).

If I was really intending on using slo mo in my final cut, I think I'd rather rent the ultimate than splash out 3K more for a couple of shots. Shame there's such a cash difference between the two.

Chris

[Bill Pryor]

Increasing shutter speed has nothing to do with frame rate.
Sony's EX series are probably the best thing in low priced camcorders for limited slomo. There's also the HVX200a--it will go up to 60fps too, but then you're into P2 cards.

[Richard Hunter]

The best way I have found to get really good slow motion is by using virtualdub with an avisynth script to do the deinterlacing. Here's the method, sounds worse than it really is, so give it a try on a short sample clip. You will need to download virtualdub and avisynth, both of which are free.

First, shoot your video in 60i at 1/120s shutter or 50i at 1/100s.

Capture a clip and call it HIGHSPEED.avi (or any name you want, just make sure it matches the script below).

Create a text file with windows notepad, and enter this avisynth script:

AVISource("HIGHSPEED.avi")
complementparity
separatefields

Save the text file as 60i.avs in the same folder as HIGHSPEED.avi (same folder is important).

Run virtualdub and import the file 60i.avs file. Virtualdub will use the avisynth script to convert every field into a frame, but at this point all the frames will be half height because there is no new data created.

Apply a "resize" video filter in virtualdub, to bring the framesize back to 1440x1080.

Set the output framerate to 60fps (or 50fps if you are in PAL-land).

Set the output compression to your preferred format (I use Canopus HQ to preserve the quality) and render the file.

This will give you a 60P clip that can be slowed down to 30P or 24P in an NLE with no motion artifacts.

If you want even better deinterlacing, you can download the leakkerneldeint avisynth filter from the link below, and use the alternative script shown. I haven't actually used this method though, because the results from the one above are already so much better than doing the slo-mo directly in Vegas or Edius.

Richard




http://avisynth.org/warpenterprises/...l_20050118.zip

AviSource("myvideo.avi")
LeakKernelBob(1) # (0=BFF, 1=TFF)
AssumeFPS(29.97)#(gives 50% speed)

[Christopher Warwick]

Originally Posted by Richard Hunter

The best way I have found to get really good slow motion is by using virtualdub with an avisynth script to do the deinterlacing. Here's the method, sounds worse than it really is, so give it a try on a short sample clip. You will need to download virtualdub and avisynth, both of which are free. ... ...

Richard, that's an excellent tip, thanks I will try that out. I don't suppose you know if Twixtor does a similar process or if the method you mention is 'cleaner'. Looks like I'll need to find the time over Christmas to do some experimenting.

[Richard Hunter]

Originally Posted by Christopher Warwick

Richard, that's an excellent tip, thanks I will try that out. I don't suppose you know if Twixtor does a similar process or if the method you mention is 'cleaner'. Looks like I'll need to find the time over Christmas to do some experimenting.

Twixtor is different, it uses smarter algorithms for deinterlacing to preserve vertical resolution and at the same time minimise motion artifacts from combining fileds into frames. The result is sharper pictures that still show some blending effects due to motion.

I think you can get a demo version of Twixtor to try out, and of course vilrtualdub and avisynth are free. Keep you busy during the holidays!

Richard

[Pavel Tomanec]

Originally Posted by Richard Hunter

Twixtor is different, it uses smarter algorithms for deinterlacing to preserve vertical resolution and at the same time minimise motion artifacts from combining fileds into frames. The result is sharper pictures that still show some blending effects due to motion.

I think you can get a demo version of Twixtor to try out, and of course vilrtualdub and avisynth are free. Keep you busy during the holidays!

Richard

Hello,

I wonder would you please advice on some reliable settings for Twixtor Pro 4.5, super slow motion for example or normal slow mo, if you have it handy?

Many thanks.

[Christopher Warwick]

Pavel,

Since starting this thread, I've actually purchased the Letus adapter now and also bought Twixtor Pro 4.5, so using it a lot. In fact I'm due to publish my first experimental work shortly.

When I first installed it, I went through the tutorials and found those very useful, particularly if you're trying to accomplish something complicated.

However, with general use, I found the simplest settings to be the best order of the day. My Twixtor is for After Affects CS4, which I use in combination with Premiere Pro CS4. I don't know what your set up is...

But anyhow, the best workflow I've found is to work the edit in Premiere as normal, then, whatever portion you want to use slow motion, use the razor tool in Premiere to slice the clip on the track where you want the slow motion effect.

Next, right click on that clipped segment, choose 'replace clip with After Affects Composition' and the razor-clipped footage pops open in After Affects.

So now you have a short clip you want to slo mo in Twixtor. Because of the way AA works, you'll need to make the composition longer (multiply the current composition length by 3 if you're slowing it up by 33% for example).

At this point, remember that you can't simply apply the Twixtor effect directly to the clip because you can't 'invent' extra footage onto the clip end. The trick is to introduce and create a new solid layer object to the composition and make it the new composition length.
How to do this: Layer -> New -> Solid...

Now all we need to do is have the solid inherit the original clip as its source. So you apply the twixtor pro 4.5 effect to the solid object, not the clip.

The display will have now turned grey (as the solid layer is over the original clip by default), but if you go into the settings of the Twixtor Pro 4.5 affect assigned to the solid, make the following simple changes:
SOURCE CONTROL = You should choose the original clipped footage you just imported from Premiere. The display will now return to your original footage as it's inheriting it.
SPEED % = In this case, 33.3%, but set it to whatever speed you want it.

That's all you need to do, if you ALT-TAB over to Premiere, it is instantly updated (no need to render in AA). However what you do need to do, is extend the razor-clipped footage out two thirds more (because more footage has been created).

By the way, apply the Premiere effects after doing this procedure, not before.
Render the workspace and voila, you have the perfect slo mo footage, all ready to go in Premiere. Remember to save the AA project too as Premiere will need the settings from it next time you open it.

Hope that helps,

Chris

[Christopher Warwick]

Here is a sample experimental video I've done to show what's possible slo motion. The water movement in this piece has been cut down to 25%, so Twixtor had to make up lots of images in between... It has a nice effect if mixed with noise reduction software like neat video.

Summer Tapestry on Vimeo

Twixtor Slo motion = 25% applied to bubbly still water shot (no noise reduction here though)
However, in addition to this, I added the Neat Video noise reduction to the shot where he leans over and dips his arm in the water. It creates an interesting shot I think.

Chris

[Alex Savarie]

In FCP ive found if you are shooting at 60i you can just stack two clips and de interlace both of them. In the De interlace filter select show upper(odd) for one and show lower(even) for the other. I have gotten a skier down to around half speed to look smooth with just that technique

[Pavel Tomanec]

Thank you Christopher. Very usefull info. Will experiment with it and will post my findings in weeks. I cut in FCP 6 and After Effects CS4.

Regards,
Pavel