title: Clear /dev/fb0 last video frame after using gst-launch using command line or Qt API
body: <p>I'm using gst-launch to start streaming a camera in the /dev/fb0 framebuffer in an embedded linux system. I don't have access to <code>ioctl.h</code> or <code>fb.h</code> to do a memset manually.</p>
  
  <p>The command is something like this:</p>
  
  <blockquote>
    <p>gst-launch-1.0 imxg2dcompositor name=camera background-color=0x000000
    sink_0::xpos=200 sink_0::ypos=90 sink_0::width=450 sink_0::height=350
    ! video/x-raw,width=800,height=480 ! imxg2dvideosink
    framebuffer=/dev/fb0 use-vsync=true imxv4l2videosrc device=/dev/video0
    input=4 ! camera.sink_0 -e</p>
  </blockquote>
  
  <p>I start this command using a QProcess object from the Qt Framework (5.6) and when I invoke the "kill", "close" or "terminate" methods I always end up with the screen showing the last image taken from the camera and I would like to have the screen clear. Is it there a way to clear the <code>/dev/fb0</code> using gst-launch command?</p>