Optical Flow Time Remapping: Premiere Pro
Optical Flow time remapping enables Premiere Pro users to achieve smooth speed and framerate changes by interpolating missing frames.
Read an excerpt here and follow the link to the full article.
What kind of media can I use it with?
Optical Flow can be applied to any video clip inside a Premiere Pro sequence. However, similar to Morph Cut, Optical Flow technology has some inherent limitations, which you will want to be aware of before applying it to your media. Optical Flow needs to calculate the motion of every pixel for each frame. It does not actually know the difference between the pixels that make up your subject and the pixels that are part of your background or other objects. So you may see some visual warping if visual elements that are the same color conflict with each other, or if parts of an object get occluded from one frame to the next. For example, if your subject goes in front of a pole, the algorithm may get confused and you may see some visual artifacts there.
To minimize such outcomes, you might try some of the following things:
- Shoot with the highest framerate possible to give Optical Flow more real source frames to work with. Also, a shorter shutter speed means less motion blur, resulting in smoother interpolation.
- Be aware that the more you slow your subject down (say, to 20% or less) the more frames Premiere Pro will have to interpolate. The best results often come at 50% speed or higher, because the interpolation rate in that case is 1:1 or less.
Posted by Kim Sternisha