gboolean frame_stepping (GstEngine * engine, gboolean foward)
{
  GstFormat fmt = GST_FORMAT_BUFFERS;
  gint64 pos;
  gboolean ok;
  g_print ("frame_steeping\n");

  if (!foward)
  {
    fmt = GST_FORMAT_TIME;
    ok = gst_element_query_position (engine->player, &fmt, &pos);
    ok = gst_element_seek (engine->player, -1.0, fmt, GST_SEEK_FLAG_FLUSH,
        GST_SEEK_TYPE_SET, pos, GST_SEEK_TYPE_NONE, pos);
    fmt = GST_FORMAT_BUFFERS;
    // g_print ("position: %ld\n", pos);
  }

  gst_element_send_event (engine->player,
      gst_event_new_step (fmt, 1, 1.0, TRUE, FALSE));

  if (!foward)
  {
    fmt = GST_FORMAT_TIME;
    ok = gst_element_query_position (engine->player, &fmt, &pos);
    ok = gst_element_seek (engine->player, 1.0, fmt, GST_SEEK_FLAG_FLUSH,
        GST_SEEK_TYPE_SET, pos, GST_SEEK_TYPE_NONE, pos);
    fmt = GST_FORMAT_BUFFERS;
    // g_print ("position: %ld\n", pos);
  }

  return FALSE;
}