Make a movie from a set of PNG images, using ffmpeg

makemovie.sh

framerate=60
i=0
padtowidth=6
for plot in plot-??????.png; do
  ln -s $plot `printf "frame-%0*d.png \n" $padtowidth $i`;
  let i=i+1
done

ffmpeg -framerate $framerate \
       -i frame-%06d.png \
       -c:v libx264 \
       -r $framerate \
       -pix_fmt yuv420p \
       -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" \
       movie.mp4

rm frame-*.png