Use ffmpeg to create a small motion background

ffmpeg.sh

# Download ffmpeg with all the good stuff (requires homebrew)
brew install ffmpeg --with-fdk-aac --with-ffplay --with-freetype --with-frei0r --with-libass --with-libvo-aacenc --with-libvorbis --with-libvpx --with-opencore-amr --with-openjpeg --with-opus --with-rtmpdump --with-schroedinger --with-speex --with-theora --with-tools

# get video information
ffmpeg -i filename.mp4

# strip out audio
ffmpeg -i input.mp4 -vcodec copy -an output.mp4

# rescale video
# Common 16:9 video scales
# 854×480, 768x 432
# 640×360, 512×288
# 320×180, 256×144
ffmpeg -i input.mp4 -vf scale=256:144 output.mp4