title: Dropping video frames
body: <p>my question is pretty simple, I think. And it's more about math than coding. 
  I receive 15 frames per second from web-cam. But I have to drop some of these. For example, if client is requesting 8 fps - I do drop each second frame and it's ok. But how should I drop if 12 fps or 6 fps are requested?</p>
  
  <p>I think there's some common algo for values distribution. Thanks a lot!</p>