ffmpeg -i add-task.mov -c:v libvpx-vp9 -b:v 0 -crf 30 -pix_fmt yuv420p add-task.webm
ffmpeg -i add-task.webm -i palette.png -filter_complex "fps=15,scale=800:-1:flags=lanczos[x];[x][1:v]paletteuse=dither=bayer:bayer_scale=5:diff_mode=rectangle" add-task.gif