Mine

static gboolean
cb_have_data (GstPad    *pad,
	      GstBuffer *buffer,
	      gpointer   u_data)
{
  GstBuffer *buf;
  g_print("Have data\n");
  buf = gst_buffer_copy (buffer);
  GstPadBufferAllocFunction (pad2, buf-> offset, buf->size, buf->caps, buf);
  gst_pad_remove_data_probe (pad, (guint) cb_id);
   gst_bus_add_watch (gst_pipeline_get_bus (GST_PIPELINE (imagebin)),
		     my_bus_callback, NULL);
  gst_element_set_state (imagebin, GST_STATE_PLAYING);

  return TRUE;
}