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I have used twixtor myself for a few projects but I have never had terrific success with it. One of the best filmmakers I know who uses Twixtor really well is my friend Salomon Ligthelm, whom I met when he lived in Dubai back in January last year. He put up a new video a couple of days ago, Gravity, and he was kind enough to write this guest blog post on how to get the best out of it.

Twixtor will not give you as good results as a dedicated high speed camera of course. They do that job incredibly well. You need to light a lot to make them work but as you will read below you need to do the same with twixtor to get the high shutter speeds needed. But for those whose budget means renting a Phantom Flex or something similar is out of the question Salomon guides you through the best ways to make the most out this powerful, but tricky plug-in. 

 

Gravity – Director’s Cut from Salomon on Vimeo.

Let me quickly explain how Twixtor works: It takes your footage [generally your transcoded 50fps, or 60fps footage and “guesses/interpolates” your missing/in-between frames

I guess with every project the approach is somewhat different. When Twixtor becomes a part of my workflow I need to become increasingly more aware of the way I am shooting so that I have workable footage in post.

I wanted to shoot something different to all the other Twixtor stuff I’ve been seeing – which have all been shot outside. I wanted to try shooting super slomo using the Canon 7D and Twixtor in interiors.

Here are a few key things to consider when working with Twixtor:

Shooting Workflow:

1. Shoot at a fast shutter: anything 1/2000 – 1/4000s. [so your lighting needs to be good]

2. Shoot against a plain/solid colored background – sky/wall etc etc.

3. Shoot at the highest point of action. The law of nature is that what must goes up, must come down. Its the movement at the top of an arc/trajectory that works best for Twixtor because that’s when things generally move the slowest, more frames of the relevant action for Twixtor to work with.

4. When you shoot really close/tight, slow the action down manually ie – move slower and fake slow motion [all the tight sequences in 'Gravity' was done this way and then slowed down a little more with the tools]. Its easier to get good results with Twixtor when the action is shot from a distance, because of the fact that the action will happen across more frames – ie – Imagine moving your arms up and down – a distance 50 centimeters right in front of the camera – the camera will only catch SOME of that action as your arms pass by the front of the lens, for maybe 1-3 frames. However if you move away from the camera and shoot say 10-15 meters away from the lens, you would catch the ENTIRE action across say 7-10 frames – giving Twixtor more information to work with

5. Shoot at 50 or 60fps. When you shoot high-speed you give Twixtor more info to work with – it is a shame that you have to forgo resolution

6. Shoot as much as you can – try to get the action from different angles – reshoot stuff if wasn’t working, or if your settings weren’t correct. SHOOT MUCH!

Post Workflow:

1. Use Twixtor in After Effects – for some reason Twixtor works best in After Effects – for me at least. Probably because After Effects’ ability to manipulate time is so effective.

So here’s what I do in a typical scenario.

– Edit the entire piece in an NLE [Non-linear Editor - like Final Cut] and then I’d

leave sections in the timeline open, or maybe reference clips that I want to

work with eventually in After Effects using Twixtor – you can’t do too much in

FCP at this stage because we’re going to be playing with time-changes – which

can screw up things if you don’t work carefully]

– Move the whole piece over to After Effects via an XML script called Popcorn

Island FCPtoAE. You need to export an XML from FCP by going to File >

Export > XML [ for FORMAT click Apple XML Interchange Format, Version 5]

– Open AE and go to scripts – look for FCPtoAE and then pull up the exported

XML

– Now click on the clip you want to use Twixtor on:  from the MENU go to LAYER

> TIME > ENABLE TIME REMAPPING. This allows you to extend a clip our for

longer – because when you start slowing stuff down, the clip needs to become

longer, which you can now easily do by enabling time remapping – just pull out

the edges using the drag function on the clip

2. Check that your Twixtor settings match your footage ie – Make sure your frame rate is correct when you set up Twixtor’s settings. If its not correct then Twixtor will stutter across your footage

– I typically shoot and edit in 23.976fps because I like the film aesthetic.

– I generally find that manipulating the image to a slower speed – say anything

between 2-5% yields better results than trying to get something workable at

30%. I don’t know why that is, but I reckon it has something to do with the fact

that with many more frames created it uses those created frames to reference

from in order to create more ‘interpolated/guessed’ frames.

3. Consider using an aspect matte to hide warping. I often use an aspect ratio of 2.4:1 in my work as a lot of my warping happens at the edges of my shots, thus a matte will hide the really bad sections. One instance of this was a shot in the short of mine called [Fo'tis'ma], where my good friend Franzwa is taking off from a ledge [Its the tight - slightly angled down shot at 34s]. The warping on his hand was REALLY bad – especially because the shot was rather tight and he was coming down at such a pace. It was because of that shot not working at 16:9 that I decided to make the whole piece 2.4:1 [IMAGE 1 & 2]

4. Avoid warping by editing well. Many times Twixtor works for only a few frames – if that’s the case I’ll only use it for a few frames and will cut to the next image – to avoid things looking crappy [obviously this must be done tastefully]. Don’t hang on too long on a shot that was good to start with but warped into mush at the end – EDIT WELL.

I trust this helps some of you out.

For more info on other parts of the creative process [color, editing, sound design] check out my blog www.salomonligthelm.blogspot.com

 

 

 

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Comments

  1. Thats a cool vid, My friend Danny and I attempted to twixtor fire and water for a challenge, as its difficult to predict, I don’t think its been done in the same video before – so its worth a look: http://www.vimeo.com/21919856 – I also posted up a tutorial here: http://vimeo.com/23151793

  2. paul wood says:

    Philip, thanks for posting this. I am currently in the process of learning twixtor, so this is great information. nice one. And thanks to Salomon too or course.

  3. clint says:

    This is a great guest blog post, the video is great too.
    I love when you post tutorial stuff up here it is awesome to see something done but even more awesome to see how.
    Thank yous all around.

  4. clint says:

    I would also love to hear about the color grading you did on this project and the other one those are also very very nice.

  5. Petter Misje says:

    I’m gonna learn how to use Twixtor! :-)
    On a different note – I have some footage shot indoors in the wrong shutter speed. The result; wavy lines moving across the picture.
    Does anybody know if there is a fix for this???

    1. Are they rolling bands? If so, here is one video tutorial on how to make it less noticeable. http://vimeo.com/13717050

      1. Petter Misje says:

        Gonna check this out straight away – thank you so much!

  6. Looks great. With slo-mo in mind, not sure whether to buy the Canon XF105 or the Sony NX70.
    The Canon can’t do slow-mo like the Sony and 200 fps looks pretty good even without Twixtor.
    http://vimeo.com/26495111

  7. I’ve had luck using the “Time Warp” feature in After Effects in place of Twixtor. I don’t have the cash for Twixtor, and Time Warp is already part of AE. It delivers decent results, as well! Check it out:

  8. Quim Bel says:

    All of your post are helpful, but this one it’s really helpful to me! I’ve been playing around with optical flow and Twixtor a lot with different results. I’ll try this tips for sure next time!

  9. Dowie says:

    Salomon you are a guru. If anyone has Apple Motion, you can use Optical Flow to get the same results as Twixtor. Check this super slow longboard sliding vid out.. http://www.vimeo.com/13359521 it’s all done with Optical Flow.

  10. conrad says:

    thank you both for that post, was very helpful. and salomon’s vids are great

  11. derek hillier says:

    I agree the new Motion or FCPX has the optical flow that shake had very cheap and easier way to do it, at AE hates you making clips longer so you have to do a bit of a work around

  12. I like you Philip never got the best results. I am so glad you posted this It helps out a lot. Thank you.

  13. mike says:

    Hi, I used twixtor with FCP and I think it worked just fine, you really need solid background as it was said before, fast shutter of course helps as well. Check this out: http://vimeo.com/21024158

  14. Bernard says:

    Amazing film and a great write up. I hope to be able to test twixtor myself one day… Just need to get more lights…

  15. Art Bell says:

    This is so interesting. We go back and forth between Twixtor and Optical image flow in Motion a lot and i have learned similar – and a few different things – coming from DSLR in my case.
    Love the ‘highest point of action’ thought thats brilliant – as the slo mo just increases the tension already here. Thanks.

    1.Most importantly as Salomon infers ‘jello happens’. To minimize it – high contrast, simple backgrounds and get close.

    2. In our tests i have found no algorithmic difference between the two – jello in one – jello in the other – its how you shot not the math that is doing you in.

    3. for the 7D – any shutter over 800 seems to degrade the quality of the image. Don’t ask me why but there just seems to be less info there. If its a good hi con, close shot – let the math do the work – take it to 1% as above – it will hold.

    4. We found the roundtripping in FCP and Motion to be easier ( less tech) so thats where we have ended up.

    We have our workflow here http://vimeo.com/22811341 if you want to see the Apple centric step by step workflow.

    Thanks, LOVE slo mo’s!

  16. Drazen says:

    love this video and I cant wait to apply some of this twixtor wisdom to one of my next projects

  17. Rob Kaczmark says:

    Wow, this is a great tutorial. Thx so much Phillip :)

    1. Philip Bloom says:

      thanks Salomon. Not me!

  18. Kym Fielke says:

    This incredible BASE jumping piece has gone viral in the past several days – good Twixtoring and colour grading of GoPro-only footage: http://vimeo.com/29017795

  19. Matt Popay says:

    Salomons work is incredible.
    I’ve already played around with Twixtor ( http://www.vimeo.com/17811423 ) but can never get the same results.
    Will be following these tips to the letter!

  20. Lance says:

    Can someone please explain to me why one needs to have Twixtor for super slo-mo as a plug in to Adobe After Effects when said effect already exists in Adobe After Effects?

    Macdonald’s video proves the point to me. After Effects alone is pretty good and I can see just as many artifacts in AE as I do in Twixtor vids.

    Also – if I MUST get Twixtor (and I’m not yet convinced) do I need to have AE or will it work as a plug-in for CS5.5 alone?

    Twixtor’s website is not very helpful for these questions.

  21. Bernhard B. says:

    Philip,

    I’m struggling to get decent lighting indoors when using such shutter speeds, may I ask what you used?

    I’m trying to capture some scenes shot at night time with no outloor light pouring in, so it’s all some 500W lights filling the room. Even though I have to compensate by boosting the ISO a lot the images are still too dark at say anything faster than 1/800 :(

    1. Philip Bloom says:

      Am afraid for shutter speeds that high you need big strong lights. 1kw and upwards!

      1. Bernhard B. says:

        Figured you’d say that, ah well, obvious I guess ;)
        Cheers!

  22. paris says:

    Philip,

    “Shoot at a fast shutter: anything 1/2000 – 1/4000s”
    how about GoPro?
    I’ve been shooting a lot of videos by using 60D/550D/GoPro & im trying to use Twixtor..its work but my video still have a “smart blur/melt blur”(i dont know how to called it,sorry)…Can you help me how to clean the “smart blur/melt blur” after using Twixtor..

    Thank you
    Sorry for my english….

  23. So, guys, if i use 5DmkII with native full HD + 24 fps, if i use good settings for shutter speed (1/1000 – 1/4000) and ISO…can i reach good results using Twixtor or not? Because till this moment i only had weird results with many many big blending ghosts…it looks like kinda morphing)) but not a slowmo)
    thanx

  24. zenith7 says:

    Great article,thanks! I am shooting a hair commercial, and with low budget I cannot afford the phantom or any other camera to shoot proper slomo.

    Shooting beauty hair shots (ala Pantene, twists,turns,drops of cascading hair – yeah right!) on Varicam at 60fps for 25 fps PAL, and then wanting to use Twixtor to try and get 120fps. Editing on FCP with AE as you advise

    I read your worklow suggestions and it really clarifies things – especially about the distance etc being key to maximise succes in terms of Twixtor interpreting frames, and was wanting to know if anyone can advise me on:

    1. Static shots better?
    2. End of lens, shallow depth of field wanted i.e BG out of focus, salon behind with variable blurred shapes etc – best to keep hair contained in frame?
    3. Lighting with 2k Tungstens and probably Kinos’ what shutter speed and angle would be best? Or what 15 amp lighjting would work best – dont have genny or 3 phase (nor budget for HMI’s!)

    A taxing list I’m sure yet I would be really grateful if anyone can give me some advice!!

    Kind Regards

    Dennis Scully