(a) get the dimensions (vinfo2 file.mov)
(b) plug the dimensions into the command line

It seems that the best way to convert to GIF is to use the exact
dimensions of the original. In the below case the original was
1112x980. As straight-up GIF was about 1.5MB. Using the smaller
dimension, 0.6 of each each, blew up the file size to about 25MB. It's
best to make the original video capture smaller.


$ ffmpeg -ss 00:00:00.000 -i zigzag1.mov -pix_fmt rgb24 -r 10 -s 1666x388  -t 00:00:53.000 zigzag1.gif

$ ffmpeg -ss 00:00:00.000 -i zigzag2.mov -pix_fmt rgb24 -r 10 -s 1666x388  -t 00:00:53.000 zigzag2.gif