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Twixtor slow motion problem

Dec 18, 2011 4:57 AM

Hello, I was using twixtor to modify some footage I have and make it slow motion but for some reasons everytime I turn the speed down the footage is blurred and it has some kind bad frame timing. I modified the frames from the composition to be exactly like the ones from my footage so there shouldn't be any problem.

 

twix.jpg

 
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  • Currently Being Moderated
    Dec 18, 2011 5:15 AM   in reply to grandill

    You're looking in all the wrong places... Check your footage interpretation rather than messing with the comp framerate and Twix' settings. And when you do, keep in mind that 24 fps is not the same as 23.97 fps or any of that, including fake reverse pulldown, fields and all that other stuff that figures in. Also set your interpolation settings in Twix to motion estimation or motion weighted blend. This gives much better results in most cases.

     

    Mylenium

     
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    Dec 18, 2011 4:35 PM   in reply to grandill

    Here the important question:  how MUCH are you making Twixtor slow the clip down?

     

    2 times, or 50% speed?  No sweat.

    5 times, or 20% speed?  That's getting dicey.

    10 times, or 10% Speed?  Fuggetaboutit.

     

    Twixtor's good, but it can't work miracles.

     
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    Dec 18, 2011 2:57 PM   in reply to grandill

    Twixtor works great for many kinds of shots. If you're going to do slow motion and you are stuck with standard video (HD or SD) you should shoot interlaced at as high a frame rate as you can. Some cameras have the ability to shoot 60P, that's even better. Once you get past the 60p mark you are into the specialty gear and the sky is the limit there. Some guys have even invented a fancy camera array that shoots trillions of frames a second. Fast enough to see a particle of light.

     

    That said, if I had some 1080i footage I'd separate fields, double the comp's frame rate, render to a 10 bit production codec, then drop that 59.97fps footage in a new comp and fire up twixtor. Providing there is the right kind of motion in the frames, Twixtor will do an amazing job of slowing down the footage. Try the same thing with 24P footage and you've got nothing but headaches.

     
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    Dec 19, 2011 4:55 AM   in reply to grandill

    Have you gone through the tutorials on the ReVision site? If you're getting all kinds of weird results you've got something fouled up in the settings. How much of a speed reduction are you trying to do? Stretching 1 second to 10 is going to be tricky, but stretching 1 second to 5 should be doable unless there's an astounding lack of detail in your shot.

     

    I'd love to see the shot you're trying to slow down.

     
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    Dec 19, 2011 9:20 AM   in reply to Rick Gerard

    D90? A Caonon DSLR? Have you unpacked the MPG4 to frame-based codec first?

     

    bogiesan

     
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    Dec 19, 2011 10:32 AM   in reply to grandill

    How much do you want to slow this clip down?

     
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    Dec 19, 2011 10:58 AM   in reply to grandill

    What is the source's codec?

    You can be a noobie only for so long around here. Then you are forced by peer pressure to dive into the mechanics of what is a huge, deep, and ultra complex application. If you are trying to apply Twixtor to a i-frame codec like what normally comes out of a DSLT, H.264, every frame must be parinfully reconstructed from the keyframes. This takes about ten time as long as trying to aply Twixtor to a conventionally uncompressed codec.

     
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    Dec 19, 2011 1:31 PM   in reply to grandill

    "Stock footage" is not helpful. That's like saying it's a Quicktime file. What codec is it? Exactly.

    Once we know that, we have path. Until then, we're guessing and that's a waste of time.

     
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    Dec 19, 2011 2:26 PM   in reply to grandill

    Oh, my. I have no idea what gspot is or what it does. Just stick with the tools you have in AE.

     

    And, just so you don't tell us it's an AVI, know that AVI is not a codec, it's just a wrapper, like Quicktime.

     

    In an earlier post you claimed to be using footage from something called a d90. Are you or are you not?

     

    > I can't believe there's no way to make some quality slow motion with a d90.<

     

    Message was edited by: bogiesan

     
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    Dec 19, 2011 2:43 PM   in reply to grandill

    grandill wrote:

    I can't believe there's no way to make some quality slow motion with a d90.

     

    A NIKON D-90?  Sorry, but you picked the wrong camera, bud.

     

    According to my information, that thing shoots 720p 24 and nothing else, which is the worst frame rate you could get for slo-mo work.  25p would be the next-worst.  There's only so much you can do to slow that stuff down before the image quality starts going down the toilet. 

     

    You would have stood a fighting chance at fairly good-looking slo-mo with with a Canon 7D, which at least can shoot 720p60.  Just conforming video from it to 24p makes it 2.5 times slower.  Combined with Twixtor taking it the speed down by a factor of 4, and you'd have video 10 times slower than normal.

     

    But a 7D has its weaknesses, too: that stinky long-gop h.264 codec, for one.  You'd have to convert the footage to a lossless codec before using it in AE.

     
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    Dec 19, 2011 3:04 PM   in reply to grandill

    I just got a good look at your screen grab, and you're headed for trouble. 

     

    You've set the speed in Twixtor to 3%!  Three percent of normal speed, which would be 100%!  That is more than THIRTY-THREE TIMES slower than normal!

     

    And you're wondering why Twixtor doesn't come thorough like a champ?  You're lucky to have any kind of image at all!

     

    You want something that slow?  Go rent a camera that's designed to shoot slo-mo.  You're asking for the impossible.

     
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    Dec 19, 2011 9:59 PM   in reply to grandill
     
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    Dec 20, 2011 8:09 AM   in reply to Taverino

    I took a look at the footage and it looks like the frame rate is wrong. It's hard to tell because you put up an FLV file and didn't post the original footage. The FLV does not contain all of the frames and the frame rate doesn't match the movie because there are a bunch of repeated frames.

     

    Here are a few thoughts.

    1. You shot with a DSLR so there are some rolling shutter problems that must be fixed to keep the car from distorting. There are plug-ins for that. Fix the rolling shutter problems (jello cam) first.
    2. You may have interlacing issues and 3:2 pulldown issues. Make sure that every frame of the movie is properly interpreted. You can do this by dragging the original clip into the new comp icon, then doubling the frame rate of the composition, then interpreting the footage as interlaced. If the footage is interlaced you'll see a different frame every time you advance one frame. If you see 2 or 3 different frames, then 2 duplicate frames, the footage has 3:2 pulldown. You must remove it. If, after you set footage interpretation to separate fields you only see pairs of frames, then the footage is truly progressive.
    3. Once you have the footage properly interpreted make sure that the interpretation is exactly copied to the appropriate fields in Twixtor and experiment with all the settings, isolate the background, and you should get acceptable results.

    None of these suggestions will work if your footage is misinterpreted. If you want to post the original footage to You Send It or Dropbox I'll gladly take a look when I can.

     
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    Dec 29, 2011 7:38 AM   in reply to grandill

    I just saw a great video comparing twixtor and adobe premier pro's applications for slowmo:

     

    http://eduardoangel.com/2011/12/27/how-much-is-slow-mo-worth-twixtor-v s-adobe-premiere-pro-cs5/

     

    A lot of people are still experiencing problems with twixtor, but once it is rendered it looks pretty damn good!  Is anyone using other slowmo applications that might not be as expensive as twixtor?

     
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    Dec 29, 2011 7:54 AM   in reply to macuser88

    macuser88 wrote:

    Is anyone using other slowmo applications that might not be as expensive as twixtor?

     

    There might be, but I doubt it.  The Magic Bullet slo-mo plugin also works well, but it's also in the same price range.

     

    I started using AE with version 3.1.  Magic Bullet and Twixtor were common then, and people are still recommending them; hence my doubt.

     
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    Dec 29, 2011 8:22 AM   in reply to Dave LaRonde

    We've had great luck simply using the optical flow built into FCP and Motion.

    The best way to get good slow motion is to shoot it using appropriate technologies like a camera that will shoot at least 90 frames per second. Difficult to convince an inexperienced producer but usually cheaper in the long run to rent or buy a suitable camera than to mess with pixel-mapping applications for days in post.These decisions must be made during the preplanning phase to make sure the footage from a rented camera will incorporate into the rest of the project's images. All pixel flow evaluation and interframe creation software requires excellent source footage and those specifications are rarely considered during shooting because the software is purchased after the primary shoting has been wrapped.

     
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    Jan 6, 2012 6:21 AM   in reply to bogiesan

    http://eduardoangel.com/2011/12/27/how-much-is-slow-mo-worth-twixtor-v s-adobe-premiere-pro-cs5/

     

    It seems that the slow motion editing in FCP is just ok.  It is not as smooth as Twixtor in my opinion.  In the link above, you can see how FCP's slow mo looks a bit choppy.  Is it because the photographer was not shooting at 90 fps.  It is shot with a Canon EOS 7D and I believe the highest that will go is 30 fps.  What are some cameras that will shoot higher than this?

     
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    Jan 6, 2012 8:04 AM   in reply to macuser88

    Go to the Abel Cine web site at look at the Phantom Camera.

     
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    Jan 7, 2012 8:17 AM   in reply to Dave LaRonde

    Thanks David...I have seen the Phantom in action before.  Simply Incredible!

     
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