Install `ffmpeg` on Mac (from https://gist.github.com/clayton/6196167#gistcomment-3017801)

install_ffmpeg.sh

brew tap homebrew-ffmpeg/ffmpeg
brew install homebrew-ffmpeg/ffmpeg/ffmpeg --with-chromaprint /
--with-fdk-aac /
--with-game-music-emu /
--with-libbluray /
--with-libbs2b /
--with-libcaca /
--with-libgsm /
--with-libmodplug /
--with-librsvg /
--with-libsoxr /
--with-libssh /
--with-libvidstab /
--with-libvmaf /
--with-libxml2 /
--with-opencore-amr /
--with-openh264 /
--with-openjpeg /
--with-openssl /
--with-rtmpdump /
--with-rubberband /
--with-speex /
--with-srt /
--with-tesseract /
--with-two-lame /
--with-wavpack /
--with-webp /
--with-xvid /
--with-zeromq /
--with-zimg