SHOOTING FOR TWIXTOR
A common question here is what are the best camera settings so we get the best Twixtor results.
Many cameras offer aside control for the shutter speed, options for FPS, resolution, compression
rate, progressive or interlaced modes.
A general rule of thumb would be the more frames per second you have the better. That would be
720P 60 FPS is recommended over 1080P 24 FPS for example, or even 1080 60i over 1080 30P.
Also the shortest possible shutter speed resulting in the less possible motion blur streaks in the
image will help Twixtor as well. Of course the “thruthness” of all this is relative to does these
settings produce without Twixtor a good image quality. Fast exposure in not as well lighten areas
can create annoying video noise, or some cameras might compress too much the image at higher
frame rates…
You might notice some people that shoot on a skateboard their friend jumping off a cliff on a
trick bike… So sports in general (fast action) are the type of footage that in general benefit from
more FPS. It is so because if you have 2X more frames to start Twixtor only has to look within a
window twice as small to match to create the in-between. More frames per second also make it
more robust for objects closer to the camera… A fundamental reason is basically the less pixels
travelled between two frames. The worst case for Twixtor being someone running sideways close
to camera.
Some camera manuals will tell you to shoot with longer shutter speed and we just say the less
motion blur the better for the motion analysis. Some people actually use our RSMB regular
(ReelSmart Motion Blur) after the fact to create a more filmic look.
So, if your options are 720 60P and 1080 30P – go 720 60P if you want to do slowmo… That is,
resizing 1.5X is safer then inbetweening 2X more frames. For someone else who has 1080 60i
and 1080 24P, for twixtor 1080 60i will usually be better (usually = unless some guy wears a
checkboard shirt).. Of course there is a limit to that logic, if your DSLR can do 300 FPS at
320×240 pixels and you need to export a 1080P project, well OK the slow-mo will be perfect but
there will be major spatial resolution issues.
Source: Twixtor for FCPX manual
