Posted by on 1 Feb, 2010 in Tutorials | 0 comments

Converting 25p into 50p

I was thrilled to find that a piece of software that I already owned performs beautiful conversions from 25p to 50p or standard frame rate to super slow-motion with virtually no shuddering. Using Adobe After Effects CS3 or higher gives you the option of pixel motion frame blending when re-timing a clip.

I had received a 25p render of a 3D animation flythrough. It looked fantastic, but it was 25fps, so when the camera was doing rapid sideways movement there was the shuddering that made it look terrible. Using After Effects I was able to convert the 25p into 50p that was seamless, saving the client bucket loads on getting the animation re-rendered into 50p.

Traditionally slow-motion conversions were only achieved through taking one frame and taking the next frame, placing a transitional frame between the two that was a combination of both frames one and two – aka dissolving.

Frame 1 Transitional Frame Frame 3

There are software packages now that do one step better than simply dissolving between frames. After Effects CS3 CREATES frames to go between image one and two where it looks as to where the motion is in frame 1, where it is in frame 2, then creates an in-between frame where the motion has been analyzed and the subject moved into the space between.

Frame 1 Transitional Frame Frame 3

The result is a seamless transition between the frames and perfectly smooth motion. This feature can be used both for converting from 25Fps to 50Fps, or for taking a clip that has been shot at normal speed and slowing it down to a half or even a quarter of it’s normal speed.

If you don’t own After Effects CS3, I can convert up to a 30 second clip for you (giving you a 1 minute slow-motion clip) for $50 AUD which will save you the expense of parting with $1,500 for After Effects. Please contact me via email and I’ll let you know what to do from there.

Below I’ve included two video tutorials on how to do this using After Effects.

25P to 50P or 25i using After Effects from Philip Johns on Vimeo.

Frame blended slow motion conversions with After Effects from Philip Johns on Vimeo.

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