Twixtor?

[Korhan20]

I know this has been discussed here before..... but I wanted a some more specific details about what to do. To achieve smooth slow motion, you can shoot at 60i, and change fields to frames and slow the footage down but you lose vertical resolution that way. My final output will be 24p.

1: Is the vertical resolution loss worth getting that slow motion footage? Will it be extremely noticeable?

2: How do these other programs work? (Twixtor and Motion Perfect) There is a huge price difference between them. Is Twixtor worth the extra money? If I have the option of using Twixtor ? should I do it? Or should I just use that bob deinterlacer and slow it down my self? Will there be a considerable difference in the quality of the slow motion footage?

[Phil Rhodes]

Hi,

 

> 1: Is the vertical resolution loss worth getting that slow motion footage? Will it

> be extremely noticeable?

 

Try it. I never have, but I imagine it'll be pretty obvious. If you're shooting the rest of your movie at 24p native and not delacing it, I'd imagine you'd want to avoid the technique if you can. On the other hand, MotionPerfect rarely is perfect, so I'd try both. 60fps is pretty damn slow, after all.

 

> 2: How do these other programs work?

 

It uses similar technology to the way temporal compression works in video compression schemes like MPEG. The computer grabs a chunk of the image - a square, or perhaps some area based on an edge-detect matrix, and then hunts around the same area of the frame for an image that looks a bit like it in nearby frames. It then calculates the motion vector (how far it's moved, and in what direction), performs a morph between the two chunks of image, and puts the result at some midway point on the motion vector. There's obviously a lot of subtlety to this, such as how carefully and how far you search for matching image, how you try to match image, how you do the morph and create the morph targets, etc, etc - which affect the quality of the result.

 

> There is a huge price difference between them.

 

Isn't there just. It's an imperfect process; you're basically paying for less imperfection. Twixtor also has more controllability - it lets you hilight areas of the frame which aren't working so well and suggest alternative interpolation techniques. Things like counter-motion - where one object moves against the other and is transparent, such as a bike wheel's spokes - tend to confuse them, as the motion in the frame approaches the temporal resolution of the recording medium and many things look alike.

 

> Is Twixtor worth the extra money?

 

I hear very good reviews of it; see if you can get a demo version.

 

Try the bob delace; see if you're happy with it.

 

Phil

[Thomas Worth]

1: Is the vertical resolution loss worth getting that slow motion footage? Will it be extremely noticeable?

<{POST_SNAPBACK}>

I, personally, prefer the look of deinterlacing and slowing down the footage. B) My problem with Twixtor and MotionPerfect is that they introduce weird motion artifacts as they go on their "hunt" for matching pixels. I don't like it at all.

 

There are very good deinterlacing tools available. FieldsKit, from Revision FX, analyzes the fields and deinterlaces based on how much change there is from frame to frame. I would use that along with slowing down the footage to 23.976p in After Effects.

 

Remember, it's a tradeoff. You can either live with the decreased vertical resolution, or live with the weird motion artifacts produced with either Twixtor or MotionPerfect. Personally, I would rather live with the "decreased" resolution, even though good deinterlacing tools make it less obvious.

 

If you want an example of BOTH Twixtor AND MotionPerfect, click the link below. The left half of the frame is Twixtor, and the right is MotionPerfect:

 

http://rarevision.com/articles/varispeed_test.php