What's the ffmpeg command to extract PPM files from an existing video? What's the ffmpeg command to extract PPM (or Portable Pix Map) files from an existing video? 

Like the reverse of this https://askubuntu.com/questions/971119/convert-a-sequence-of-ppm-images-to-avi-video
ffmpeg -i input.mp4 output_%04d.ppm


Output files will be named output_0001.ppm, output_0002.ppm, etc. See the image muxer documentation for more options and info.