Improved version of https://unix.stackexchange.com/questions/419761/webp-animation-to-gif-animation-cli
Dependent packages: webp, imagemagick
use apt install webp imagemagick
Python version of webp2gif.sh, in memory, faster
Dependent packages: webp, imageio
use python3 -m pip install webp imageio
c++ version of webp2gif, much faster
using gif-h at https://github.com/charlietangora/gif-h
Dependent packages: libwebpdemux2 libtbb-dev
use
apt install libwebpdemux2 libtbb-dev build-essential g++
to install dependency
and
g++ webp2gif.cpp -o webp2gif -std=c++17 -lwebp -lwebpdemux -ltbb -lstdc++fs
to build