Making an animated gif

2019.08.25

In my last post I wanted to lead off with a short animation of the 3D printer in action. I had a video I shot on my phone that looked nice, so I downloaded it and started looking at ffmpeg options. Eventually I stitched together a few snippets from others with some critical thinking of my own and came up with this:

#!/bin/sh

vid=vid.mp4
start_time=00:00:01
duration=3
height=320       # input height halved , can replace with pixils .
width=-2         # keeps aspect ratio . can replace with pixils .
fps=10           # frames per a second .

filters="fps=$fps,scale=$width:$height:flags=lanczos"

ffmpeg -ss $start_time                             \
       -t  $duration                               \
       -i  "$vid"                                  \
       -vf "$filters,palettegen"                   \
       -y  palette.png                             &&
ffmpeg -ss $start_time                             \
       -t  $duration                               \
       -i  "$vid"                                  \
       -i  palette.png                                \
       -lavfi "$filters [x]; [x][1:v] paletteuse=dither=bayer:bayer_scale=5:diff_mode=rectangle"  \
       -y  "$vid".gif                              &&
rm palette.png

It got the gif pretty small, but I still ran it through another web-based optimizer to get the size down more. I’m sure it’s possible to do that extra optimization here, but this is where good ideas run short on time, right?