synfig is a vector based 2D animation package. It is designed to be
capable of producing feature-film quality animation. It eliminates the
need for tweening, preventing the need to hand-draw each frame. synfig
features spatial and temporal resolution independence (sharp and smooth
at any resolution or framerate), high dynamic range images, and a
flexible plugin system.

This package contains the renderer used to convert synfig .sif files to
raster images, videos and other formats. Layer types include geometric,
gradient, filter, distortion, transformation, fractal and others. Output
targets include JPEG, PNG, GIF, BMP, PPM, DV, OpenEXR, ffmpeg (MPEG1),
libavcodec (AVI), imagemagick (MIFF), yuv420p and others.

WWW: http://www.synfig.com/