static void
kms_composite_mixer_port_data_destroy (gpointer data)
{
  KmsCompositeMixerData *port_data = (KmsCompositeMixerData *) data;
  KmsCompositeMixer *self = port_data->mixer;
  GstPad *audiosink;
  gchar *padname;

  KMS_COMPOSITE_MIXER_LOCK (self);

  port_data->removing = TRUE;

  kms_base_hub_unlink_video_sink (KMS_BASE_HUB (self), port_data->id);
  kms_base_hub_unlink_audio_sink (KMS_BASE_HUB (self), port_data->id);

  if (port_data->input) {
    GstEvent *event;
    gboolean result;
    GstPad *pad;

    if (port_data->videorate == NULL) {
      KMS_COMPOSITE_MIXER_UNLOCK (self);
      return;
    }

    pad = gst_element_get_static_pad (port_data->videorate, "sink");

    if (pad == NULL) {
      KMS_COMPOSITE_MIXER_UNLOCK (self);
      return;
    }

    if (!GST_OBJECT_FLAG_IS_SET (pad, GST_PAD_FLAG_EOS)) {

      event = gst_event_new_eos ();
      result = gst_pad_send_event (pad, event);

      if (port_data->input && self->priv->n_elems > 0) {
        port_data->input = FALSE;
        self->priv->n_elems--;
        kms_composite_mixer_recalculate_sizes (self);
      }
      KMS_COMPOSITE_MIXER_UNLOCK (self);

      if (!result) {
        GST_WARNING ("EOS event did not send");
      }
    } else {
      gboolean remove = FALSE;

      /* EOS callback was triggered before we could remove the port data */
      /* so we have to remove elements to avoid memory leaks. */
      remove = port_data->eos_managed;
      KMS_COMPOSITE_MIXER_UNLOCK (self);

      if (remove) {
        /* Remove pipeline without helding the mutex */
        kms_loop_idle_add_full (self->priv->loop, G_PRIORITY_DEFAULT,
            (GSourceFunc) remove_elements_from_pipeline,
            KMS_COMPOSITE_MIXER_REF (port_data),
            (GDestroyNotify) kms_ref_struct_unref);
      }
    }
    gst_element_unlink (port_data->input_capsfilter, port_data->videoconvert);
    gst_element_unlink (port_data->videoconvert, port_data->videorate);
    g_object_unref (pad);
  } else {
    if (port_data->probe_id > 0) {
      gst_pad_remove_probe (port_data->video_mixer_pad, port_data->probe_id);
    }

    if (port_data->link_probe_id > 0) {
      gst_pad_remove_probe (port_data->videoconvert_sink_pad,
          port_data->link_probe_id);
    }
    KMS_COMPOSITE_MIXER_UNLOCK (self);

    gst_element_unlink (port_data->input_capsfilter, port_data->videoconvert);

    gst_bin_remove (GST_BIN (self), g_object_ref (port_data->input_capsfilter));
    gst_element_set_state (port_data->input_capsfilter, GST_STATE_NULL);
    g_object_unref (port_data->input_capsfilter);
    port_data->input_capsfilter = NULL;

    gst_bin_remove (GST_BIN (self), g_object_ref (port_data->videoconvert));
    gst_element_set_state (port_data->videoconvert, GST_STATE_NULL);
    g_object_unref (port_data->videoconvert);
    port_data->videoconvert = NULL;
  }

  padname = g_strdup_printf (AUDIO_SINK_PAD, port_data->id);
  audiosink = gst_element_get_static_pad (self->priv->audiomixer, padname);
  gst_element_release_request_pad (self->priv->audiomixer, audiosink);
  gst_object_unref (audiosink);
  g_free (padname);
}
static GstPadProbeReturn
link_to_videomixer (GstPad * pad, GstPadProbeInfo * info,
    KmsCompositeMixerData * data)
{
  GstPadTemplate *sink_pad_template;
  KmsCompositeMixer *mixer;

  if (GST_EVENT_TYPE (GST_PAD_PROBE_INFO_EVENT (info)) !=
      GST_EVENT_STREAM_START) {
    return GST_PAD_PROBE_PASS;
  }

  mixer = KMS_COMPOSITE_MIXER (data->mixer);
  GST_DEBUG ("stream start detected %d", data->id);
  KMS_COMPOSITE_MIXER_LOCK (mixer);

  data->link_probe_id = 0;

  sink_pad_template =
      gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (mixer->priv->
          videomixer), "sink_%u");

  if (G_UNLIKELY (sink_pad_template == NULL)) {
    GST_ERROR_OBJECT (mixer, "Error taking a new pad from videomixer");
    KMS_COMPOSITE_MIXER_UNLOCK (mixer);
    return GST_PAD_PROBE_DROP;
  }

  if (mixer->priv->videotestsrc == NULL) {
    GstElement *capsfilter;
    GstCaps *filtercaps;
    GstPad *pad;

    mixer->priv->videotestsrc = gst_element_factory_make ("videotestsrc", NULL);
    capsfilter = gst_element_factory_make ("capsfilter", NULL);

    g_object_set (mixer->priv->videotestsrc, "is-live", TRUE, "pattern",
        /*black */ 2, NULL);

    filtercaps =
        gst_caps_new_simple ("video/x-raw", "format", G_TYPE_STRING, "AYUV",
        "width", G_TYPE_INT, mixer->priv->output_width,
        "height", G_TYPE_INT, mixer->priv->output_height,
        "framerate", GST_TYPE_FRACTION, 15, 1, NULL);
    g_object_set (G_OBJECT (capsfilter), "caps", filtercaps, NULL);
    gst_caps_unref (filtercaps);

    gst_bin_add_many (GST_BIN (mixer), mixer->priv->videotestsrc,
        capsfilter, NULL);

    gst_element_link (mixer->priv->videotestsrc, capsfilter);

    /*link capsfilter -> videomixer */
    pad = gst_element_request_pad (mixer->priv->videomixer, sink_pad_template,
        NULL, NULL);

    gst_element_link_pads (capsfilter, NULL,
        mixer->priv->videomixer, GST_OBJECT_NAME (pad));
    g_object_set (pad, "xpos", 0, "ypos", 0, "alpha", 0.0, NULL);
    g_object_unref (pad);

    gst_element_sync_state_with_parent (capsfilter);
    gst_element_sync_state_with_parent (mixer->priv->videotestsrc);
  }

  data->videoscale = gst_element_factory_make ("videoscale", NULL);
  data->capsfilter = gst_element_factory_make ("capsfilter", NULL);
  data->videorate = gst_element_factory_make ("videorate", NULL);
  data->queue = gst_element_factory_make ("queue", NULL);
  data->input = TRUE;

  gst_bin_add_many (GST_BIN (mixer), data->queue, data->videorate,
      data->videoscale, data->capsfilter, NULL);

  g_object_set (data->videorate, "average-period", 200 * GST_MSECOND, NULL);
  g_object_set (data->queue, "flush-on-eos", TRUE, "max-size-buffers", 60,
      NULL);

  gst_element_link_many (data->videorate, data->queue, data->videoscale,
      data->capsfilter, NULL);

  /*link capsfilter -> videomixer */
  data->video_mixer_pad =
      gst_element_request_pad (mixer->priv->videomixer,
      sink_pad_template, NULL, NULL);
  gst_element_link_pads (data->capsfilter, NULL,
      mixer->priv->videomixer, GST_OBJECT_NAME (data->video_mixer_pad));

  gst_element_link (data->videoconvert, data->videorate);

  data->probe_id = gst_pad_add_probe (data->video_mixer_pad,
      GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM,
      (GstPadProbeCallback) cb_EOS_received,
      KMS_COMPOSITE_MIXER_REF (data), (GDestroyNotify) kms_ref_struct_unref);

  gst_element_sync_state_with_parent (data->videoscale);
  gst_element_sync_state_with_parent (data->capsfilter);
  gst_element_sync_state_with_parent (data->videorate);
  gst_element_sync_state_with_parent (data->queue);

  /*recalculate the output sizes */
  mixer->priv->n_elems++;
  kms_composite_mixer_recalculate_sizes (mixer);

  KMS_COMPOSITE_MIXER_UNLOCK (mixer);

  return GST_PAD_PROBE_REMOVE;
}
static GstPadProbeReturn
link_to_videomixer (GstPad * pad, GstPadProbeInfo * info,
    KmsCompositeMixerData * data)
{
  GstPadTemplate *sink_pad_template;
  KmsCompositeMixer *mixer;
  GstPad *tee_src;

  if (GST_EVENT_TYPE (GST_PAD_PROBE_INFO_EVENT (info)) !=
      GST_EVENT_STREAM_START) {
    return GST_PAD_PROBE_PASS;
  }

  mixer = KMS_COMPOSITE_MIXER (data->mixer);
  GST_DEBUG ("stream start detected %d", data->id);
  KMS_COMPOSITE_MIXER_LOCK (mixer);

  data->link_probe_id = 0;
  data->latency_probe_id = 0;

  sink_pad_template =
      gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (mixer->
          priv->videomixer), "sink_%u");

  if (G_UNLIKELY (sink_pad_template == NULL)) {
    GST_ERROR_OBJECT (mixer, "Error taking a new pad from videomixer");
    KMS_COMPOSITE_MIXER_UNLOCK (mixer);
    return GST_PAD_PROBE_DROP;
  }

  data->input = TRUE;

  /*link tee -> videomixer */
  data->video_mixer_pad =
      gst_element_request_pad (mixer->priv->videomixer,
      sink_pad_template, NULL, NULL);

  tee_src = gst_element_get_request_pad (data->tee, "src_%u");

  gst_element_link_pads (data->tee, GST_OBJECT_NAME (tee_src),
      mixer->priv->videomixer, GST_OBJECT_NAME (data->video_mixer_pad));
  g_object_unref (tee_src);

  data->probe_id = gst_pad_add_probe (data->video_mixer_pad,
      GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM,
      (GstPadProbeCallback) cb_EOS_received,
      KMS_COMPOSITE_MIXER_REF (data), (GDestroyNotify) kms_ref_struct_unref);

  data->latency_probe_id = gst_pad_add_probe (data->video_mixer_pad,
      GST_PAD_PROBE_TYPE_QUERY_UPSTREAM,
      (GstPadProbeCallback) cb_latency, NULL, NULL);

  /*recalculate the output sizes */
  mixer->priv->n_elems++;
  kms_composite_mixer_recalculate_sizes (mixer);

  //Recalculate latency to avoid video freezes when an element stops to send media.
  gst_bin_recalculate_latency (GST_BIN (mixer));

  KMS_COMPOSITE_MIXER_UNLOCK (mixer);

  return GST_PAD_PROBE_REMOVE;
}