Ewo converting to Gif/Webp

[Thomas Buckley-Houston]

This one works for Tom:

ffmpeg \
  -i sample.mp4 \
  -vcodec libwebp \
  -filter:v fps=fps=20 \
  -lossless 1 \
  -loop 0 \
  -preset default \
  -an \
  -fps_mode auto \
  -s 800:600 converted.webp