Different FPS??

[Walter Soyka]

[anna holck] “And also when you interpret you 50 FPS to 25. Can you further adjust the slowtion speed? And how? And i’m assuming that that won’t make it loose quality either?”

The reason that there is no quality loss for slowing down “overcranked” (high frame rate) footage to the lower frame rate of your project is that you are still only using the original footage.

If you shoot 1 second at 50 frames per second, you have 50 frames. If you play then play those 50 frames back at a rate of 25 frames per second, it will take 2 seconds to play what you recorded in 1 second. That’s the math behind overcranked slow motion.

If you want to slow the footage down further, say to 10 frames per second, you have to deal with the fact that your deliverable is still 25 frames per second. This is where “quality loss” comes in. In order to fit 10 into 25, you need to make up some frames. You’ll either have to repeat frames (which will look stuttery), blend existing frames together (which will look soft), or synthesize new frames (which may introduce artifacts).

Twixtor (or Ae’s built-in Pixel Motion frame blending mode or Timewarp effect) use a technique called “optical flow” to estimate the motion in between two real frames to imagine what a frame might look if it had been captured in between them. It can work, but it’s not magic, and it may make your footage look “gloopy.”

One other note on quality loss: for things like resizing and retiming, you can see any quality loss right away. What you see is what you get.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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