onvif: encapsulate onvif part into a bin

...and thus do not let onvif affect pipelines latency

https://bugzilla.gnome.org/show_bug.cgi?id=797174

gst/rtsp-server/Makefile.am

@@ -31,6 +31,7 @@ c_sources = \
 	rtsp-params.c \
 	rtsp-sdp.c \
 	rtsp-thread-pool.c \
+	rtsp-latency-bin.c \
 	rtsp-media.c \
 	rtsp-media-factory.c \
 	rtsp-media-factory-uri.c \

gst/rtsp-server/meson.build

@@ -3,6 +3,7 @@ rtsp_server_sources = [
   'rtsp-auth.c',
   'rtsp-client.c',
   'rtsp-context.c',
+  'rtsp-latency-bin.c',
   'rtsp-media.c',
   'rtsp-media-factory.c',
   'rtsp-media-factory-uri.c',

gst/rtsp-server/rtsp-latency-bin.c

@@ -0,0 +1,357 @@
+/* GStreamer
+ * Copyright (C) 2018 Ognyan Tonchev <ognyan@axis.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include "rtsp-latency-bin.h"
+
+#define GST_RTSP_LATENCY_BIN_GET_PRIVATE(obj)  \
+     (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_RTSP_LATENCY_BIN_TYPE, GstRTSPLatencyBinPrivate))
+
+struct _GstRTSPLatencyBinPrivate
+{
+  GstPad *sinkpad;
+  GstElement *element;
+};
+
+enum
+{
+  PROP_0,
+  PROP_ELEMENT,
+  PROP_LAST
+};
+
+GST_DEBUG_CATEGORY_STATIC (rtsp_latency_bin_debug);
+#define GST_CAT_DEFAULT rtsp_latency_bin_debug
+
+static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS_ANY);
+
+static void gst_rtsp_latency_bin_get_property (GObject * object, guint propid,
+    GValue * value, GParamSpec * pspec);
+static void gst_rtsp_latency_bin_set_property (GObject * object, guint propid,
+    const GValue * value, GParamSpec * pspec);
+static gboolean gst_rtsp_latency_bin_element_query (GstElement * element,
+    GstQuery * query);
+static gboolean gst_rtsp_latency_bin_element_event (GstElement * element,
+    GstEvent * event);
+static void gst_rtsp_latency_bin_message_handler (GstBin * bin,
+    GstMessage * message);
+static gboolean gst_rtsp_latency_bin_add_element (GstRTSPLatencyBin *
+    latency_bin, GstElement * element);
+static GstStateChangeReturn gst_rtsp_latency_bin_change_state (GstElement *
+    element, GstStateChange transition);
+
+G_DEFINE_TYPE_WITH_PRIVATE (GstRTSPLatencyBin, gst_rtsp_latency_bin,
+    GST_TYPE_BIN);
+
+static void
+gst_rtsp_latency_bin_class_init (GstRTSPLatencyBinClass * klass)
+{
+  GObjectClass *gobject_klass = G_OBJECT_CLASS (klass);
+  GstElementClass *gstelement_klass = GST_ELEMENT_CLASS (klass);
+  GstBinClass *gstbin_klass = GST_BIN_CLASS (klass);
+
+  GST_DEBUG_CATEGORY_INIT (rtsp_latency_bin_debug,
+      "rtsplatencybin", 0, "GstRTSPLatencyBin");
+
+  gobject_klass->get_property = gst_rtsp_latency_bin_get_property;
+  gobject_klass->set_property = gst_rtsp_latency_bin_set_property;
+
+  g_object_class_install_property (gobject_klass, PROP_ELEMENT,
+      g_param_spec_object ("element", "The Element",
+          "The GstElement to prevent from affecting piplines latency",
+          GST_TYPE_ELEMENT, G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE));
+
+  gstelement_klass->change_state =
+      GST_DEBUG_FUNCPTR (gst_rtsp_latency_bin_change_state);
+  gstelement_klass->query =
+      GST_DEBUG_FUNCPTR (gst_rtsp_latency_bin_element_query);
+  gstelement_klass->send_event =
+      GST_DEBUG_FUNCPTR (gst_rtsp_latency_bin_element_event);
+
+  gstbin_klass->handle_message =
+      GST_DEBUG_FUNCPTR (gst_rtsp_latency_bin_message_handler);
+}
+
+static void
+gst_rtsp_latency_bin_init (GstRTSPLatencyBin * latency_bin)
+{
+  GST_OBJECT_FLAG_SET (latency_bin, GST_ELEMENT_FLAG_SINK);
+}
+
+static void
+gst_rtsp_latency_bin_get_property (GObject * object, guint propid,
+    GValue * value, GParamSpec * pspec)
+{
+  GstRTSPLatencyBin *latency_bin = GST_RTSP_LATENCY_BIN (object);
+  GstRTSPLatencyBinPrivate *priv =
+      GST_RTSP_LATENCY_BIN_GET_PRIVATE (latency_bin);
+
+  switch (propid) {
+    case PROP_ELEMENT:
+      g_value_set_object (value, priv->element);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, propid, pspec);
+  }
+}
+
+static void
+gst_rtsp_latency_bin_set_property (GObject * object, guint propid,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstRTSPLatencyBin *latency_bin = GST_RTSP_LATENCY_BIN (object);
+
+  switch (propid) {
+    case PROP_ELEMENT:
+      if (!gst_rtsp_latency_bin_add_element (latency_bin,
+          g_value_get_object (value))) {
+        GST_WARNING_OBJECT (latency_bin, "Could not add the element");
+      }
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, propid, pspec);
+  }
+}
+
+static gboolean
+gst_rtsp_latency_bin_add_element (GstRTSPLatencyBin * latency_bin,
+    GstElement * element)
+{
+  GstRTSPLatencyBinPrivate *priv =
+      GST_RTSP_LATENCY_BIN_GET_PRIVATE (latency_bin);
+  GstPad *pad;
+  GstPadTemplate *templ;
+
+  GST_DEBUG_OBJECT (latency_bin, "Adding element to latencybin : %s",
+      GST_ELEMENT_NAME (element));
+
+  if (!element) {
+    goto no_element;
+  }
+
+  /* add the element to ourself */
+  gst_object_ref (element);
+  gst_bin_add (GST_BIN (latency_bin), element);
+  priv->element = element;
+
+  /* add ghost pad first */
+  templ = gst_static_pad_template_get (&sinktemplate);
+  priv->sinkpad = gst_ghost_pad_new_no_target_from_template ("sink", templ);
+  gst_object_unref (templ);
+  g_assert (priv->sinkpad);
+
+  gst_element_add_pad (GST_ELEMENT (latency_bin), priv->sinkpad);
+
+  /* and link it to our element */
+  pad = gst_element_get_static_pad (element, "sink");
+  if (!pad) {
+    goto no_sink_pad;
+  }
+
+  if (!gst_ghost_pad_set_target (GST_GHOST_PAD_CAST (priv->sinkpad), pad)) {
+    goto set_target_failed;
+  }
+
+  gst_object_unref (pad);
+
+  return TRUE;
+
+  /* ERRORs */
+no_element:
+  {
+    GST_WARNING_OBJECT (latency_bin, "No element, not adding");
+    return FALSE;
+  }
+no_sink_pad:
+  {
+    GST_WARNING_OBJECT (latency_bin, "The element has no sink pad");
+    return FALSE;
+  }
+set_target_failed:
+  {
+    GST_WARNING_OBJECT (latency_bin, "Could not set target pad");
+    gst_object_unref (pad);
+    return FALSE;
+  }
+}
+
+
+static gboolean
+gst_rtsp_latency_bin_element_query (GstElement * element,
+    GstQuery * query)
+{
+  gboolean ret = TRUE;
+
+  GST_LOG_OBJECT (element, "got query %s", GST_QUERY_TYPE_NAME (query));
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_LATENCY:
+      /* ignoring latency query, we do not want our element to affect latency on
+       * the rest of the pipeline */
+      GST_DEBUG_OBJECT (element, "ignoring latency query");
+      gst_query_set_latency (query, FALSE, 0, -1);
+      break;
+    default:
+      ret =
+          GST_ELEMENT_CLASS (gst_rtsp_latency_bin_parent_class)->query (
+              GST_ELEMENT (element), query);
+      break;
+  }
+
+  return ret;
+}
+
+static gboolean
+gst_rtsp_latency_bin_element_event (GstElement * element,
+    GstEvent * event)
+{
+  gboolean ret = TRUE;
+
+  GST_LOG_OBJECT (element, "got event %s", GST_EVENT_TYPE_NAME (event));
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_LATENCY:
+      /* ignoring latency event, we will configure latency on our element when
+       * going to PLAYING */
+      GST_DEBUG_OBJECT (element, "ignoring latency event");
+      gst_event_unref (event);
+      break;
+    default:
+      ret = GST_ELEMENT_CLASS (
+              gst_rtsp_latency_bin_parent_class)->send_event (
+              GST_ELEMENT (element), event);
+      break;
+  }
+
+  return ret;
+}
+
+static gboolean
+gst_rtsp_latency_bin_recalculate_latency (GstRTSPLatencyBin * latency_bin)
+{
+  GstRTSPLatencyBinPrivate *priv =
+      GST_RTSP_LATENCY_BIN_GET_PRIVATE (latency_bin);
+  GstEvent *latency;
+  GstQuery *query;
+  GstClockTime min_latency;
+
+  GST_DEBUG_OBJECT (latency_bin, "Recalculating latency");
+
+  if (!priv->element) {
+    GST_WARNING_OBJECT (latency_bin, "We do not have an element");
+    return FALSE;
+  }
+
+  query = gst_query_new_latency ();
+
+  if (!gst_element_query (priv->element, query)) {
+    GST_WARNING_OBJECT (latency_bin, "Latency query failed");
+    gst_query_unref (query);
+    return FALSE;
+  }
+
+  gst_query_parse_latency (query, NULL, &min_latency, NULL);
+  gst_query_unref (query);
+
+  GST_LOG_OBJECT (latency_bin, "Got min_latency from stream: %"
+      GST_TIME_FORMAT, GST_TIME_ARGS (min_latency));
+
+  latency = gst_event_new_latency (min_latency);
+  if (!gst_element_send_event (priv->element, latency)) {
+    GST_WARNING_OBJECT (latency_bin, "Sending latency event to stream failed");
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+static void
+gst_rtsp_latency_bin_message_handler (GstBin * bin, GstMessage * message)
+{
+  GstRTSPLatencyBin *latency_bin = GST_RTSP_LATENCY_BIN (bin);
+
+  GST_LOG_OBJECT (bin, "Got message %s", GST_MESSAGE_TYPE_NAME (message));
+
+  switch (GST_MESSAGE_TYPE (message)) {
+    case GST_MESSAGE_LATENCY:{
+      if (!gst_rtsp_latency_bin_recalculate_latency (latency_bin)) {
+        GST_WARNING_OBJECT (latency_bin, "Could not recalculate latency");
+      }
+      break;
+    }
+    default:
+      GST_BIN_CLASS (gst_rtsp_latency_bin_parent_class)->handle_message (
+              bin, message);
+      break;
+  }
+}
+
+static GstStateChangeReturn
+gst_rtsp_latency_bin_change_state (GstElement * element, GstStateChange
+    transition)
+{
+  GstRTSPLatencyBin *latency_bin = GST_RTSP_LATENCY_BIN (element);
+  GstStateChangeReturn ret;
+
+  GST_LOG_OBJECT (latency_bin, "Changing state %s",
+      gst_state_change_get_name (transition));
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
+    case GST_STATE_CHANGE_PLAYING_TO_PLAYING:
+      if (!gst_rtsp_latency_bin_recalculate_latency (latency_bin)) {
+        GST_WARNING_OBJECT (latency_bin, "Could not recalculate latency");
+      }
+    default:
+      break;
+  }
+
+  ret = GST_ELEMENT_CLASS (gst_rtsp_latency_bin_parent_class)->change_state
+      (element, transition);
+
+  return ret;
+}
+
+/**
+ * gst_rtsp_latency_bin_new:
+ * @element: (transfer full): a #GstElement
+ *
+ * Create a bin that encapsulates an @element and prevents it from affecting
+ * latency on the whole pipeline.
+ *
+ * Returns: A newly created #GstRTSPLatencyBin element, or %NULL on failure
+ */
+GstElement *
+gst_rtsp_latency_bin_new (GstElement * element)
+{
+  GstElement *gst_rtsp_latency_bin;
+
+  g_return_val_if_fail (element, NULL);
+
+  gst_rtsp_latency_bin = g_object_new (GST_RTSP_LATENCY_BIN_TYPE, "element",
+      element, NULL);
+  gst_object_unref (element);
+  return gst_rtsp_latency_bin;
+}

gst/rtsp-server/rtsp-latency-bin.h

@@ -0,0 +1,59 @@
+/* GStreamer
+ * Copyright (C) 2018 Ognyan Tonchev <ognyan@axis.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_RTSP_LATENCY_BIN_H__
+#define __GST_RTSP_LATENCY_BIN_H__
+
+#include <gst/gst.h>
+#include "rtsp-server-prelude.h"
+
+G_BEGIN_DECLS
+
+typedef struct _GstRTSPLatencyBin GstRTSPLatencyBin;
+typedef struct _GstRTSPLatencyBinClass GstRTSPLatencyBinClass;
+typedef struct _GstRTSPLatencyBinPrivate GstRTSPLatencyBinPrivate;
+
+#define GST_RTSP_LATENCY_BIN_TYPE                 (gst_rtsp_latency_bin_get_type ())
+#define IS_GST_RTSP_LATENCY_BIN(obj)              (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_RTSP_LATENCY_BIN_TYPE))
+#define IS_GST_RTSP_LATENCY_BIN_CLASS(klass)      (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_RTSP_LATENCY_BIN_TYPE))
+#define GST_RTSP_LATENCY_BIN_GET_CLASS(obj)       (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_RTSP_LATENCY_BIN_TYPE, GstRTSPLatencyBinClass))
+#define GST_RTSP_LATENCY_BIN(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_RTSP_LATENCY_BIN_TYPE, GstRTSPLatencyBin))
+#define GST_RTSP_LATENCY_BIN_CLASS(klass)         (G_TYPE_CHECK_CLASS_CAST ((klass), GST_RTSP_LATENCY_BIN_TYPE, GstRTSPLatencyBinClass))
+#define GST_RTSP_LATENCY_BIN_CAST(obj)            ((GstRTSPLatencyBin*)(obj))
+#define GST_RTSP_LATENCY_BIN_CLASS_CAST(klass)    ((GstRTSPLatencyBinClass*)(klass))
+
+struct _GstRTSPLatencyBin {
+  GstBin parent;
+
+  GstRTSPLatencyBinPrivate *priv;
+};
+
+struct _GstRTSPLatencyBinClass {
+  GstBinClass parent_class;
+};
+
+GST_RTSP_SERVER_API
+GType gst_rtsp_latency_bin_get_type (void);
+
+GST_RTSP_SERVER_API
+GstElement * gst_rtsp_latency_bin_new (GstElement * element);
+
+G_END_DECLS
+
+#endif /* __GST_RTSP_LATENCY_BIN_H__ */

gst/rtsp-server/rtsp-onvif-media.c

@@ -42,6 +42,7 @@
 #endif
 
 #include "rtsp-onvif-media.h"
+#include "rtsp-latency-bin.h"
 
 struct GstRTSPOnvifMediaPrivate
 {
@@ -251,6 +252,7 @@ gboolean
 gst_rtsp_onvif_media_collect_backchannel (GstRTSPOnvifMedia * media)
 {
   GstElement *element, *backchannel_bin = NULL;
+  GstElement *latency_bin;
   GstPad *pad = NULL;
   gboolean ret = FALSE;
 
@@ -265,11 +267,28 @@ gst_rtsp_onvif_media_collect_backchannel (GstRTSPOnvifMedia * media)
   if (!backchannel_bin)
     goto out;
 
-  pad = gst_element_get_static_pad (backchannel_bin, "sink");
+  /* We don't want the backchannel element, which is a receiver, to affect
+   * latency on the complete pipeline. That's why we remove it from the
+   * pipeline and add it to a @GstRTSPLatencyBin which will prevent it from
+   * messing up pipelines latency. The extra reference is needed so that it
+   * is not freed in case the pipeline holds the the only ref to it.
+   *
+   * TODO: a more generic solution should be implemented in
+   * gst_rtsp_media_collect_streams() where all receivers are encapsulated
+   * in a @GstRTSPLatencyBin in cases when there are senders too. */
+  gst_object_ref (backchannel_bin);
+  gst_bin_remove (GST_BIN (element), backchannel_bin);
+
+  latency_bin = gst_rtsp_latency_bin_new (backchannel_bin);
+  g_assert (latency_bin);
+
+  gst_bin_add (GST_BIN (element), latency_bin);
+
+  pad = gst_element_get_static_pad (latency_bin, "sink");
   if (!pad)
     goto out;
 
-  gst_rtsp_media_create_stream (GST_RTSP_MEDIA (media), backchannel_bin, pad);
+  gst_rtsp_media_create_stream (GST_RTSP_MEDIA (media), latency_bin, pad);
   ret = TRUE;
 
 out: