CineGobs Keyer is a freeware.
What is it for?
With CineGobs keyer you can key out backgrounds and export the video including transparency to your other software.
Easy to use.
Color difference keyer with 4 different algorithms.
Detail matte to add extra details.
Chroma keyer. Hue, Shadow and Highlight mattes.
Mattes can be blurred and shrunk/eroded
Rotoscoping. Create garbage mattes and additive mattes with interpolated keyframes.
Spill suppression with different algorithms.
Imports AVI video, AviSynth files & image sequences (PNG/JPG and BMP) of any size.
Deinterlacing: Blend, Discard upper & Discard lower
Exports AVI files or image sequences with alpha, premultiplied with alpha or alpha only.
Multi threaded for a more responsive user interface.