title: ffmpeg reduce memory consumption
body: <p>I'm developing an application, capturing some ip camera with RTSP protocols and send them to one server.
  everything is going well when the resolution of ip cameras is low but when they're increased the memory consumption of my program goes up suddenly.</p>
  
  <p>I've realized that ffmpeg stores a sequence of frames which we can seek to. 
  1.is there any way to reduce the len of that? </p>
  
  <p>2.is it possible to reduce the frame size when the ffmpeg reads the frames from the input(=>ip camera)? the size 400x400 is enough for my app but currently it's 2048</p>
  
  <p>3.or any other way to help me reduce memory usage</p>