title: GStreamer change image size dynamically
body: <p>First of all: yes I know this has been asked before but the answer doesnt really help me as I am not that familiar with Gstreamer yet and I need some more help. I'm trying to make a pipeline with <code>videocrop</code> and change the values dynamically. The following is my code which returns the error: <code>TypeError: object of type GstVideoCrop does not have property caps</code>. So I guess it's either not possible or I'm doing it the wrong way... Thank you for your help!</p>
  <pre><code>import gi
  gi.require_version('Tcam', '0.1')
  gi.require_version('Gst', '1.0')
  from gi.repository import GObject, Gst, Tcam
  
  GObject.threads_init()
  Gst.init(())
  p = Gst.parse_launch(&quot;tcambin name=src ! video/x-raw, format=BGRx ! videocrop name=try top=0 left=300 right=150 bottom=0 ! videoconvert ! ximagesink&quot;)
  p.set_state(Gst.State.PLAYING)
  p.set_state(Gst.State.READY)
  m = p.get_by_name(&quot;try&quot;)
  caps = Gst.caps_from_string(&quot;videocrop name=try top=500 left=300 right=150 bottom=0&quot;)
  m.set_property(&quot;caps&quot;, caps)
  p.set_state(Gst.State.PLAYING)
  GObject.MainLoop.run()
  </code></pre>