title: How to attach metadata to each frame of a video
body: <p>I would like to be able to store metadata on each frame of a video file (a key to value map with ~10 entries per frame). </p>
  
  <p>Which video format allows me to store such data ?</p>
  
  <p>Where can I find a c++ library to do this ?</p>
  
  <p>Thank you very much for your answers.</p>