* Go faster stripes: don't check to see if the user presses 'q' if stdin
  returns EOF -- e.g. it is connected to /dev/null
* Make the 1MB video buffer only allocated once rather than on each frame.
  The allocation and deallocation causes significant performance loss as the
  kernel remaps the address space each time.

Originally committed as revision 629 to svn://svn.ffmpeg.org/ffmpeg/trunk
