Use MAY_BE_LEAKED_FLAG
[platform/upstream/gstreamer.git] / libs / gst / net / gstnetclientclock.c
index 8b59a2a..0b3e4df 100644 (file)
 GST_DEBUG_CATEGORY_STATIC (ncc_debug);
 #define GST_CAT_DEFAULT (ncc_debug)
 
+typedef struct
+{
+  GstClock *clock;              /* GstNetClientInternalClock */
+
+  GList *clocks;                /* GstNetClientClocks */
+
+  GstClockID remove_id;
+} ClockCache;
+
+G_LOCK_DEFINE_STATIC (clocks_lock);
+static GList *clocks = NULL;
+
+#define GST_TYPE_NET_CLIENT_INTERNAL_CLOCK \
+  (gst_net_client_internal_clock_get_type())
+#define GST_NET_CLIENT_INTERNAL_CLOCK(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_NET_CLIENT_INTERNAL_CLOCK,GstNetClientInternalClock))
+#define GST_NET_CLIENT_INTERNAL_CLOCK_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_NET_CLIENT_INTERNAL_CLOCK,GstNetClientInternalClockClass))
+#define GST_IS_NET_CLIENT_INTERNAL_CLOCK(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_NET_CLIENT_INTERNAL_CLOCK))
+#define GST_IS_NET_CLIENT_INTERNAL_CLOCK_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_NET_CLIENT_INTERNAL_CLOCK))
+
+typedef struct _GstNetClientInternalClock GstNetClientInternalClock;
+typedef struct _GstNetClientInternalClockClass GstNetClientInternalClockClass;
+
+G_GNUC_INTERNAL GType gst_net_client_internal_clock_get_type (void);
+
 #define DEFAULT_ADDRESS         "127.0.0.1"
 #define DEFAULT_PORT            5637
 #define DEFAULT_TIMEOUT         GST_SECOND
@@ -90,14 +118,15 @@ enum
   PROP_ROUNDTRIP_LIMIT,
   PROP_MINIMUM_UPDATE_INTERVAL,
   PROP_BUS,
-  PROP_BASE_TIME
+  PROP_BASE_TIME,
+  PROP_INTERNAL_CLOCK,
+  PROP_IS_NTP
 };
 
-#define GST_NET_CLIENT_CLOCK_GET_PRIVATE(obj)  \
-  (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_NET_CLIENT_CLOCK, GstNetClientClockPrivate))
-
-struct _GstNetClientClockPrivate
+struct _GstNetClientInternalClock
 {
+  GstSystemClock clock;
+
   GThread *thread;
 
   GSocket *socket;
@@ -114,45 +143,48 @@ struct _GstNetClientClockPrivate
   GstClockTime last_rtts[MEDIAN_PRE_FILTERING_WINDOW];
   gint last_rtts_missing;
 
-  GstClockTime base_time;
-
   gchar *address;
   gint port;
+  gboolean is_ntp;
 
-  GstBus *bus;
+  /* Protected by OBJECT_LOCK */
+  GList *busses;
+};
 
-  gboolean is_ntp;
+struct _GstNetClientInternalClockClass
+{
+  GstSystemClockClass parent_class;
 };
 
 #define _do_init \
   GST_DEBUG_CATEGORY_INIT (ncc_debug, "netclock", 0, "Network client clock");
-#define gst_net_client_clock_parent_class parent_class
-G_DEFINE_TYPE_WITH_CODE (GstNetClientClock, gst_net_client_clock,
-    GST_TYPE_SYSTEM_CLOCK, _do_init);
+G_DEFINE_TYPE_WITH_CODE (GstNetClientInternalClock,
+    gst_net_client_internal_clock, GST_TYPE_SYSTEM_CLOCK, _do_init);
 
-static void gst_net_client_clock_finalize (GObject * object);
-static void gst_net_client_clock_set_property (GObject * object, guint prop_id,
-    const GValue * value, GParamSpec * pspec);
-static void gst_net_client_clock_get_property (GObject * object, guint prop_id,
-    GValue * value, GParamSpec * pspec);
-static void gst_net_client_clock_constructed (GObject * object);
+static void gst_net_client_internal_clock_finalize (GObject * object);
+static void gst_net_client_internal_clock_set_property (GObject * object,
+    guint prop_id, const GValue * value, GParamSpec * pspec);
+static void gst_net_client_internal_clock_get_property (GObject * object,
+    guint prop_id, GValue * value, GParamSpec * pspec);
+static void gst_net_client_internal_clock_constructed (GObject * object);
 
-static gboolean gst_net_client_clock_start (GstNetClientClock * self);
-static void gst_net_client_clock_stop (GstNetClientClock * self);
+static gboolean gst_net_client_internal_clock_start (GstNetClientInternalClock *
+    self);
+static void gst_net_client_internal_clock_stop (GstNetClientInternalClock *
+    self);
 
 static void
-gst_net_client_clock_class_init (GstNetClientClockClass * klass)
+gst_net_client_internal_clock_class_init (GstNetClientInternalClockClass *
+    klass)
 {
   GObjectClass *gobject_class;
 
   gobject_class = G_OBJECT_CLASS (klass);
 
-  g_type_class_add_private (klass, sizeof (GstNetClientClockPrivate));
-
-  gobject_class->finalize = gst_net_client_clock_finalize;
-  gobject_class->get_property = gst_net_client_clock_get_property;
-  gobject_class->set_property = gst_net_client_clock_set_property;
-  gobject_class->constructed = gst_net_client_clock_constructed;
+  gobject_class->finalize = gst_net_client_internal_clock_finalize;
+  gobject_class->get_property = gst_net_client_internal_clock_get_property;
+  gobject_class->set_property = gst_net_client_internal_clock_set_property;
+  gobject_class->constructed = gst_net_client_internal_clock_constructed;
 
   g_object_class_install_property (gobject_class, PROP_ADDRESS,
       g_param_spec_string ("address", "address",
@@ -164,140 +196,89 @@ gst_net_client_clock_class_init (GstNetClientClockClass * klass)
           "The port on which the remote server is listening", 0, G_MAXUINT16,
           DEFAULT_PORT,
           G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
-  g_object_class_install_property (gobject_class, PROP_BUS,
-      g_param_spec_object ("bus", "bus",
-          "A GstBus on which to send clock status information", GST_TYPE_BUS,
-          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
-
-  /**
-   * GstNetClientClock::round-trip-limit:
-   *
-   * Maximum allowed round-trip for packets. If this property is set to a nonzero
-   * value, all packets with a round-trip interval larger than this limit will be
-   * ignored. This is useful for networks with severe and fluctuating transport
-   * delays. Filtering out these packets increases stability of the synchronization.
-   * On the other hand, the lower the limit, the higher the amount of filtered
-   * packets. Empirical tests are typically necessary to estimate a good value
-   * for the limit.
-   * If the property is set to zero, the limit is disabled.
-   *
-   * Since: 1.4
-   */
-  g_object_class_install_property (gobject_class, PROP_ROUNDTRIP_LIMIT,
-      g_param_spec_uint64 ("round-trip-limit", "round-trip limit",
-          "Maximum tolerable round-trip interval for packets, in nanoseconds "
-          "(0 = no limit)", 0, G_MAXUINT64, DEFAULT_ROUNDTRIP_LIMIT,
-          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
-
-  g_object_class_install_property (gobject_class, PROP_MINIMUM_UPDATE_INTERVAL,
-      g_param_spec_uint64 ("minimum-update-interval", "minimum update interval",
-          "Minimum polling interval for packets, in nanoseconds"
-          "(0 = no limit)", 0, G_MAXUINT64, DEFAULT_MINIMUM_UPDATE_INTERVAL,
-          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
-
-  g_object_class_install_property (gobject_class, PROP_BASE_TIME,
-      g_param_spec_uint64 ("base-time", "Base Time",
-          "Initial time that is reported before synchronization", 0,
-          G_MAXUINT64, DEFAULT_BASE_TIME,
-          G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_IS_NTP,
+      g_param_spec_boolean ("is-ntp", "Is NTP",
+          "The clock is using the NTPv4 protocol", FALSE,
+          G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
 }
 
 static void
-gst_net_client_clock_init (GstNetClientClock * self)
+gst_net_client_internal_clock_init (GstNetClientInternalClock * self)
 {
-  GstClock *clock = GST_CLOCK_CAST (self);
-  GstNetClientClockPrivate *priv;
+  GST_OBJECT_FLAG_SET (self, GST_CLOCK_FLAG_NEEDS_STARTUP_SYNC);
 
-  self->priv = priv = GST_NET_CLIENT_CLOCK_GET_PRIVATE (self);
+  self->port = DEFAULT_PORT;
+  self->address = g_strdup (DEFAULT_ADDRESS);
+  self->is_ntp = FALSE;
 
-  priv->port = DEFAULT_PORT;
-  priv->address = g_strdup (DEFAULT_ADDRESS);
+  gst_clock_set_timeout (GST_CLOCK (self), DEFAULT_TIMEOUT);
 
-  gst_clock_set_timeout (clock, DEFAULT_TIMEOUT);
+  self->thread = NULL;
 
-  priv->thread = NULL;
-
-  priv->servaddr = NULL;
-  priv->rtt_avg = GST_CLOCK_TIME_NONE;
-  priv->roundtrip_limit = DEFAULT_ROUNDTRIP_LIMIT;
-  priv->minimum_update_interval = DEFAULT_MINIMUM_UPDATE_INTERVAL;
-  priv->last_remote_poll_interval = GST_CLOCK_TIME_NONE;
-  priv->skipped_updates = 0;
-  priv->last_rtts_missing = MEDIAN_PRE_FILTERING_WINDOW;
-  priv->base_time = DEFAULT_BASE_TIME;
+  self->servaddr = NULL;
+  self->rtt_avg = GST_CLOCK_TIME_NONE;
+  self->roundtrip_limit = DEFAULT_ROUNDTRIP_LIMIT;
+  self->minimum_update_interval = DEFAULT_MINIMUM_UPDATE_INTERVAL;
+  self->last_remote_poll_interval = GST_CLOCK_TIME_NONE;
+  self->skipped_updates = 0;
+  self->last_rtts_missing = MEDIAN_PRE_FILTERING_WINDOW;
 }
 
 static void
-gst_net_client_clock_finalize (GObject * object)
+gst_net_client_internal_clock_finalize (GObject * object)
 {
-  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+  GstNetClientInternalClock *self = GST_NET_CLIENT_INTERNAL_CLOCK (object);
 
-  if (self->priv->thread) {
-    gst_net_client_clock_stop (self);
+  if (self->thread) {
+    gst_net_client_internal_clock_stop (self);
   }
 
-  g_free (self->priv->address);
-  self->priv->address = NULL;
+  g_free (self->address);
+  self->address = NULL;
 
-  if (self->priv->servaddr != NULL) {
-    g_object_unref (self->priv->servaddr);
-    self->priv->servaddr = NULL;
+  if (self->servaddr != NULL) {
+    g_object_unref (self->servaddr);
+    self->servaddr = NULL;
   }
 
-  if (self->priv->socket != NULL) {
-    g_socket_close (self->priv->socket, NULL);
-    g_object_unref (self->priv->socket);
-    self->priv->socket = NULL;
+  if (self->socket != NULL) {
+    if (!g_socket_close (self->socket, NULL))
+      GST_ERROR_OBJECT (self, "Failed to close socket");
+    g_object_unref (self->socket);
+    self->socket = NULL;
   }
 
-  if (self->priv->bus != NULL) {
-    gst_object_unref (self->priv->bus);
-    self->priv->bus = NULL;
-  }
+  g_warn_if_fail (self->busses == NULL);
 
-  G_OBJECT_CLASS (parent_class)->finalize (object);
+  G_OBJECT_CLASS (gst_net_client_internal_clock_parent_class)->finalize
+      (object);
 }
 
 static void
-gst_net_client_clock_set_property (GObject * object, guint prop_id,
+gst_net_client_internal_clock_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
 {
-  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+  GstNetClientInternalClock *self = GST_NET_CLIENT_INTERNAL_CLOCK (object);
 
   switch (prop_id) {
     case PROP_ADDRESS:
       GST_OBJECT_LOCK (self);
-      g_free (self->priv->address);
-      self->priv->address = g_value_dup_string (value);
-      if (self->priv->address == NULL)
-        self->priv->address = g_strdup (DEFAULT_ADDRESS);
+      g_free (self->address);
+      self->address = g_value_dup_string (value);
+      if (self->address == NULL)
+        self->address = g_strdup (DEFAULT_ADDRESS);
       GST_OBJECT_UNLOCK (self);
       break;
     case PROP_PORT:
       GST_OBJECT_LOCK (self);
-      self->priv->port = g_value_get_int (value);
+      self->port = g_value_get_int (value);
       GST_OBJECT_UNLOCK (self);
       break;
-    case PROP_ROUNDTRIP_LIMIT:
+    case PROP_IS_NTP:
       GST_OBJECT_LOCK (self);
-      self->priv->roundtrip_limit = g_value_get_uint64 (value);
+      self->is_ntp = g_value_get_boolean (value);
       GST_OBJECT_UNLOCK (self);
       break;
-    case PROP_MINIMUM_UPDATE_INTERVAL:
-      GST_OBJECT_LOCK (self);
-      self->priv->minimum_update_interval = g_value_get_uint64 (value);
-      GST_OBJECT_UNLOCK (self);
-      break;
-    case PROP_BUS:
-      GST_OBJECT_LOCK (self);
-      if (self->priv->bus)
-        gst_object_unref (self->priv->bus);
-      self->priv->bus = g_value_dup_object (value);
-      GST_OBJECT_UNLOCK (self);
-      break;
-    case PROP_BASE_TIME:
-      self->priv->base_time = g_value_get_uint64 (value);
-      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -305,37 +286,22 @@ gst_net_client_clock_set_property (GObject * object, guint prop_id,
 }
 
 static void
-gst_net_client_clock_get_property (GObject * object, guint prop_id,
+gst_net_client_internal_clock_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec)
 {
-  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+  GstNetClientInternalClock *self = GST_NET_CLIENT_INTERNAL_CLOCK (object);
 
   switch (prop_id) {
     case PROP_ADDRESS:
       GST_OBJECT_LOCK (self);
-      g_value_set_string (value, self->priv->address);
+      g_value_set_string (value, self->address);
       GST_OBJECT_UNLOCK (self);
       break;
     case PROP_PORT:
-      g_value_set_int (value, self->priv->port);
-      break;
-    case PROP_ROUNDTRIP_LIMIT:
-      GST_OBJECT_LOCK (self);
-      g_value_set_uint64 (value, self->priv->roundtrip_limit);
-      GST_OBJECT_UNLOCK (self);
-      break;
-    case PROP_MINIMUM_UPDATE_INTERVAL:
-      GST_OBJECT_LOCK (self);
-      g_value_set_uint64 (value, self->priv->minimum_update_interval);
-      GST_OBJECT_UNLOCK (self);
+      g_value_set_int (value, self->port);
       break;
-    case PROP_BUS:
-      GST_OBJECT_LOCK (self);
-      g_value_set_object (value, self->priv->bus);
-      GST_OBJECT_UNLOCK (self);
-      break;
-    case PROP_BASE_TIME:
-      g_value_set_uint64 (value, self->priv->base_time);
+    case PROP_IS_NTP:
+      g_value_set_boolean (value, self->is_ntp);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -344,35 +310,14 @@ gst_net_client_clock_get_property (GObject * object, guint prop_id,
 }
 
 static void
-gst_net_client_clock_constructed (GObject * object)
+gst_net_client_internal_clock_constructed (GObject * object)
 {
-  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
-  GstClockTime internal;
+  GstNetClientInternalClock *self = GST_NET_CLIENT_INTERNAL_CLOCK (object);
 
-  G_OBJECT_CLASS (parent_class)->constructed (object);
-
-  /* gst_clock_get_time() values are guaranteed to be increasing. because no one
-   * has called get_time on this clock yet we are free to adjust to any value
-   * without worrying about worrying about MAX() issues with the clock's
-   * internal time.
-   */
-
-  /* update our internal time so get_time() give something around base_time.
-     assume that the rate is 1 in the beginning. */
-  internal = gst_clock_get_internal_time (GST_CLOCK (self));
-  gst_clock_set_calibration (GST_CLOCK (self), internal, self->priv->base_time,
-      1, 1);
-
-  {
-    GstClockTime now = gst_clock_get_time (GST_CLOCK (self));
+  G_OBJECT_CLASS (gst_net_client_internal_clock_parent_class)->constructed
+      (object);
 
-    if (GST_CLOCK_DIFF (now, self->priv->base_time) > 0 ||
-        GST_CLOCK_DIFF (now, self->priv->base_time + GST_SECOND) < 0) {
-      g_warning ("unable to set the base time, expect sync problems!");
-    }
-  }
-
-  if (!gst_net_client_clock_start (self)) {
+  if (!gst_net_client_internal_clock_start (self)) {
     g_warning ("failed to start clock '%s'", GST_OBJECT_NAME (self));
   }
 
@@ -390,17 +335,15 @@ compare_clock_time (const GstClockTime * a, const GstClockTime * b)
 }
 
 static void
-gst_net_client_clock_observe_times (GstNetClientClock * self,
+gst_net_client_internal_clock_observe_times (GstNetClientInternalClock * self,
     GstClockTime local_1, GstClockTime remote_1, GstClockTime remote_2,
     GstClockTime local_2)
 {
-  GstNetClientClockPrivate *priv = self->priv;
   GstClockTime current_timeout = 0;
   GstClockTime local_avg, remote_avg;
   gdouble r_squared;
   GstClock *clock;
   GstClockTime rtt, rtt_limit, min_update_interval;
-  GstBus *bus = NULL;
   /* Use for discont tracking */
   GstClockTime time_before = 0;
   GstClockTime min_guess = 0;
@@ -415,19 +358,20 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
   gint i;
 
   GST_OBJECT_LOCK (self);
-  rtt_limit = self->priv->roundtrip_limit;
+  rtt_limit = self->roundtrip_limit;
+
+  GST_LOG_OBJECT (self,
+      "local1 %" G_GUINT64_FORMAT " remote1 %" G_GUINT64_FORMAT " remote2 %"
+      G_GUINT64_FORMAT " local2 %" G_GUINT64_FORMAT, local_1, remote_1,
+      remote_2, local_2);
 
   /* If the server told us a poll interval and it's bigger than the
    * one configured via the property, use the server's */
-  if (self->priv->last_remote_poll_interval != GST_CLOCK_TIME_NONE &&
-      self->priv->last_remote_poll_interval >
-      self->priv->minimum_update_interval)
-    min_update_interval = self->priv->last_remote_poll_interval;
+  if (self->last_remote_poll_interval != GST_CLOCK_TIME_NONE &&
+      self->last_remote_poll_interval > self->minimum_update_interval)
+    min_update_interval = self->last_remote_poll_interval;
   else
-    min_update_interval = self->priv->minimum_update_interval;
-
-  if (self->priv->bus)
-    bus = gst_object_ref (self->priv->bus);
+    min_update_interval = self->minimum_update_interval;
   GST_OBJECT_UNLOCK (self);
 
   if (local_2 < local_1) {
@@ -459,13 +403,13 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
   }
 
   for (i = 1; i < MEDIAN_PRE_FILTERING_WINDOW; i++)
-    self->priv->last_rtts[i - 1] = self->priv->last_rtts[i];
-  self->priv->last_rtts[i - 1] = rtt;
+    self->last_rtts[i - 1] = self->last_rtts[i];
+  self->last_rtts[i - 1] = rtt;
 
-  if (self->priv->last_rtts_missing) {
-    self->priv->last_rtts_missing--;
+  if (self->last_rtts_missing) {
+    self->last_rtts_missing--;
   } else {
-    memcpy (&last_rtts, &self->priv->last_rtts, sizeof (last_rtts));
+    memcpy (&last_rtts, &self->last_rtts, sizeof (last_rtts));
     g_qsort_with_data (&last_rtts,
         MEDIAN_PRE_FILTERING_WINDOW, sizeof (GstClockTime),
         (GCompareDataFunc) compare_clock_time, NULL);
@@ -488,17 +432,17 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
   /* Track an average round trip time, for a bit of smoothing */
   /* Always update before discarding a sample, so genuine changes in
    * the network get picked up, eventually */
-  if (priv->rtt_avg == GST_CLOCK_TIME_NONE)
-    priv->rtt_avg = rtt;
-  else if (rtt < priv->rtt_avg) /* Shorter RTTs carry more weight than longer */
-    priv->rtt_avg = (3 * priv->rtt_avg + rtt) / 4;
+  if (self->rtt_avg == GST_CLOCK_TIME_NONE)
+    self->rtt_avg = rtt;
+  else if (rtt < self->rtt_avg) /* Shorter RTTs carry more weight than longer */
+    self->rtt_avg = (3 * self->rtt_avg + rtt) / 4;
   else
-    priv->rtt_avg = (15 * priv->rtt_avg + rtt) / 16;
+    self->rtt_avg = (15 * self->rtt_avg + rtt) / 16;
 
-  if (rtt > 2 * priv->rtt_avg) {
+  if (rtt > 2 * self->rtt_avg) {
     GST_LOG_OBJECT (self,
         "Dropping observation, long RTT %" GST_TIME_FORMAT " > 2 * avg %"
-        GST_TIME_FORMAT, GST_TIME_ARGS (rtt), GST_TIME_ARGS (priv->rtt_avg));
+        GST_TIME_FORMAT, GST_TIME_ARGS (rtt), GST_TIME_ARGS (self->rtt_avg));
     goto bogus_observation;
   }
 
@@ -538,15 +482,13 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
   remote_avg = (remote_2 + remote_1) / 2;
 
   GST_LOG_OBJECT (self,
-      "local1 %" G_GUINT64_FORMAT " remote1 %" G_GUINT64_FORMAT " remote2 %"
-      G_GUINT64_FORMAT " remoteavg %" G_GUINT64_FORMAT " localavg %"
-      G_GUINT64_FORMAT " local2 %" G_GUINT64_FORMAT, local_1, remote_1,
-      remote_2, remote_avg, local_avg, local_2);
+      "remoteavg %" G_GUINT64_FORMAT " localavg %" G_GUINT64_FORMAT,
+      remote_avg, local_avg);
 
   clock = GST_CLOCK_CAST (self);
 
   /* Store what the clock produced as 'now' before this update */
-  gst_clock_get_calibration (GST_CLOCK (self), &orig_internal_time,
+  gst_clock_get_calibration (GST_CLOCK_CAST (self), &orig_internal_time,
       &orig_external_time, &orig_rate_num, &orig_rate_den);
   internal_time = orig_internal_time;
   external_time = orig_external_time;
@@ -554,15 +496,15 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
   rate_den = orig_rate_den;
 
   min_guess =
-      gst_clock_adjust_with_calibration (GST_CLOCK (self), local_1,
+      gst_clock_adjust_with_calibration (GST_CLOCK_CAST (self), local_1,
       internal_time, external_time, rate_num, rate_den);
   time_before =
-      gst_clock_adjust_with_calibration (GST_CLOCK (self), local_2,
+      gst_clock_adjust_with_calibration (GST_CLOCK_CAST (self), local_2,
       internal_time, external_time, rate_num, rate_den);
 
   /* Maximum discontinuity, when we're synched with the master. Could make this a property,
    * but this value seems to work fine */
-  max_discont = priv->rtt_avg / 4;
+  max_discont = self->rtt_avg / 4;
 
   /* If the remote observation was within a max_discont window around our min/max estimates, we're synched */
   synched =
@@ -570,14 +512,14 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
       && GST_CLOCK_DIFF (time_before,
           remote_avg) < (GstClockTimeDiff) (max_discont));
 
-  if (gst_clock_add_observation_unapplied (GST_CLOCK (self), local_avg,
-          remote_avg, &r_squared, &internal_time, &external_time, &rate_num,
-          &rate_den)) {
+  if (gst_clock_add_observation_unapplied (GST_CLOCK_CAST (self),
+          local_avg, remote_avg, &r_squared, &internal_time, &external_time,
+          &rate_num, &rate_den)) {
 
     /* Now compare the difference (discont) in the clock
      * after this observation */
     time_discont = GST_CLOCK_DIFF (time_before,
-        gst_clock_adjust_with_calibration (GST_CLOCK (self), local_2,
+        gst_clock_adjust_with_calibration (GST_CLOCK_CAST (self), local_2,
             internal_time, external_time, rate_num, rate_den));
 
     /* If we were in sync with the remote clock, clamp the allowed
@@ -605,21 +547,27 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
     /* Check if the new clock params would have made our observation within range */
     now_synched =
         (GST_CLOCK_DIFF (remote_avg,
-            gst_clock_adjust_with_calibration (GST_CLOCK (self), local_1,
-                internal_time, external_time, rate_num,
+            gst_clock_adjust_with_calibration (GST_CLOCK_CAST (self),
+                local_1, internal_time, external_time, rate_num,
                 rate_den)) < (GstClockTimeDiff) (max_discont))
-        && (GST_CLOCK_DIFF (gst_clock_adjust_with_calibration (GST_CLOCK (self),
-                local_2, internal_time, external_time, rate_num, rate_den),
+        &&
+        (GST_CLOCK_DIFF (gst_clock_adjust_with_calibration
+            (GST_CLOCK_CAST (self), local_2, internal_time, external_time,
+                rate_num, rate_den),
             remote_avg) < (GstClockTimeDiff) (max_discont));
 
     /* Only update the clock if we had synch or just gained it */
-    if (synched || now_synched || priv->skipped_updates > MAX_SKIPPED_UPDATES) {
-      gst_clock_set_calibration (GST_CLOCK (self), internal_time, external_time,
-          rate_num, rate_den);
+    if (synched || now_synched || self->skipped_updates > MAX_SKIPPED_UPDATES) {
+      gst_clock_set_calibration (GST_CLOCK_CAST (self), internal_time,
+          external_time, rate_num, rate_den);
       /* ghetto formula - shorter timeout for bad correlations */
       current_timeout = (1e-3 / (1 - MIN (r_squared, 0.99999))) * GST_SECOND;
-      current_timeout = MIN (current_timeout, gst_clock_get_timeout (clock));
-      priv->skipped_updates = 0;
+      current_timeout =
+          MIN (current_timeout, gst_clock_get_timeout (GST_CLOCK_CAST (self)));
+      self->skipped_updates = 0;
+
+      /* FIXME: When do we consider the clock absolutely not synced anymore? */
+      gst_clock_set_synced (GST_CLOCK (self), TRUE);
     } else {
       /* Restore original calibration vars for the report, we're not changing the clock */
       internal_time = orig_internal_time;
@@ -627,7 +575,7 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
       rate_num = orig_rate_num;
       rate_den = orig_rate_den;
       time_discont = 0;
-      priv->skipped_updates++;
+      self->skipped_updates++;
     }
   }
 
@@ -635,15 +583,17 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
   if (rtt < min_update_interval)
     current_timeout = MAX (min_update_interval - rtt, current_timeout);
 
-  if (bus) {
+  GST_OBJECT_LOCK (self);
+  if (self->busses) {
     GstStructure *s;
     GstMessage *msg;
+    GList *l;
 
     /* Output a stats message, whether we updated the clock or not */
     s = gst_structure_new ("gst-netclock-statistics",
         "synchronised", G_TYPE_BOOLEAN, synched,
         "rtt", G_TYPE_UINT64, rtt,
-        "rtt-average", G_TYPE_UINT64, priv->rtt_avg,
+        "rtt-average", G_TYPE_UINT64, self->rtt_avg,
         "local", G_TYPE_UINT64, local_avg,
         "remote", G_TYPE_UINT64, remote_avg,
         "discontinuity", G_TYPE_INT64, time_discont,
@@ -660,39 +610,38 @@ gst_net_client_clock_observe_times (GstNetClientClock * self,
         (gdouble) (rate_num) / rate_den, "local-clock-offset", G_TYPE_INT64,
         GST_CLOCK_DIFF (internal_time, external_time), NULL);
     msg = gst_message_new_element (GST_OBJECT (self), s);
-    gst_bus_post (bus, msg);
+
+    for (l = self->busses; l; l = l->next)
+      gst_bus_post (l->data, gst_message_ref (msg));
+    gst_message_unref (msg);
   }
+  GST_OBJECT_UNLOCK (self);
 
   GST_INFO ("next timeout: %" GST_TIME_FORMAT, GST_TIME_ARGS (current_timeout));
-  self->priv->timeout_expiration = gst_util_get_timestamp () + current_timeout;
+  self->timeout_expiration = gst_util_get_timestamp () + current_timeout;
 
-  if (bus)
-    gst_object_unref (bus);
   return;
 
 bogus_observation:
-  if (bus)
-    gst_object_unref (bus);
   /* Schedule a new packet again soon */
-  self->priv->timeout_expiration = gst_util_get_timestamp () + (GST_SECOND / 4);
+  self->timeout_expiration = gst_util_get_timestamp () + (GST_SECOND / 4);
   return;
 }
 
 static gpointer
-gst_net_client_clock_thread (gpointer data)
+gst_net_client_internal_clock_thread (gpointer data)
 {
-  GstNetClientClock *self = data;
-  GSocket *socket = self->priv->socket;
+  GstNetClientInternalClock *self = data;
+  GSocket *socket = self->socket;
   GError *err = NULL;
-  GstClock *clock = data;
 
   GST_INFO_OBJECT (self, "net client clock thread running, socket=%p", socket);
 
   g_socket_set_blocking (socket, TRUE);
   g_socket_set_timeout (socket, 0);
 
-  while (!g_cancellable_is_cancelled (self->priv->cancel)) {
-    GstClockTime expiration_time = self->priv->timeout_expiration;
+  while (!g_cancellable_is_cancelled (self->cancel)) {
+    GstClockTime expiration_time = self->timeout_expiration;
     GstClockTime now = gst_util_get_timestamp ();
     gint64 socket_timeout;
 
@@ -705,7 +654,7 @@ gst_net_client_clock_thread (gpointer data)
     GST_TRACE_OBJECT (self, "timeout: %" G_GINT64_FORMAT "us", socket_timeout);
 
     if (!g_socket_condition_timed_wait (socket, G_IO_IN, socket_timeout,
-            self->priv->cancel, &err)) {
+            self->cancel, &err)) {
       /* cancelled, timeout or error */
       if (err->code == G_IO_ERROR_CANCELLED) {
         GST_INFO_OBJECT (self, "cancelled");
@@ -715,20 +664,19 @@ gst_net_client_clock_thread (gpointer data)
         /* timed out, let's send another packet */
         GST_DEBUG_OBJECT (self, "timed out");
 
-        if (self->priv->is_ntp) {
+        if (self->is_ntp) {
           GstNtpPacket *packet;
 
           packet = gst_ntp_packet_new (NULL, NULL);
 
           packet->transmit_time =
-              gst_clock_get_internal_time (GST_CLOCK (self));
+              gst_clock_get_internal_time (GST_CLOCK_CAST (self));
 
           GST_DEBUG_OBJECT (self,
               "sending packet, local time = %" GST_TIME_FORMAT,
               GST_TIME_ARGS (packet->transmit_time));
 
-          gst_ntp_packet_send (packet, self->priv->socket,
-              self->priv->servaddr, NULL);
+          gst_ntp_packet_send (packet, self->socket, self->servaddr, NULL);
 
           g_free (packet);
         } else {
@@ -736,21 +684,22 @@ gst_net_client_clock_thread (gpointer data)
 
           packet = gst_net_time_packet_new (NULL);
 
-          packet->local_time = gst_clock_get_internal_time (GST_CLOCK (self));
+          packet->local_time =
+              gst_clock_get_internal_time (GST_CLOCK_CAST (self));
 
           GST_DEBUG_OBJECT (self,
               "sending packet, local time = %" GST_TIME_FORMAT,
               GST_TIME_ARGS (packet->local_time));
 
-          gst_net_time_packet_send (packet, self->priv->socket,
-              self->priv->servaddr, NULL);
+          gst_net_time_packet_send (packet, self->socket, self->servaddr, NULL);
 
           g_free (packet);
         }
 
         /* reset timeout (but are expecting a response sooner anyway) */
-        self->priv->timeout_expiration =
-            gst_util_get_timestamp () + gst_clock_get_timeout (clock);
+        self->timeout_expiration =
+            gst_util_get_timestamp () +
+            gst_clock_get_timeout (GST_CLOCK_CAST (self));
       } else {
         GST_DEBUG_OBJECT (self, "socket error: %s", err->message);
         g_usleep (G_USEC_PER_SEC / 10); /* throttle */
@@ -761,9 +710,9 @@ gst_net_client_clock_thread (gpointer data)
 
       /* got packet */
 
-      new_local = gst_clock_get_internal_time (GST_CLOCK (self));
+      new_local = gst_clock_get_internal_time (GST_CLOCK_CAST (self));
 
-      if (self->priv->is_ntp) {
+      if (self->is_ntp) {
         GstNtpPacket *packet;
 
         packet = gst_ntp_packet_receive (socket, NULL, &err);
@@ -783,17 +732,19 @@ gst_net_client_clock_thread (gpointer data)
 
           /* Remember the last poll interval we ever got from the server */
           if (packet->poll_interval != GST_CLOCK_TIME_NONE)
-            self->priv->last_remote_poll_interval = packet->poll_interval;
+            self->last_remote_poll_interval = packet->poll_interval;
 
           /* observe_times will reset the timeout */
-          gst_net_client_clock_observe_times (self, packet->origin_time,
-              packet->receive_time, packet->transmit_time, new_local);
+          gst_net_client_internal_clock_observe_times (self,
+              packet->origin_time, packet->receive_time, packet->transmit_time,
+              new_local);
 
           g_free (packet);
         } else if (err != NULL) {
           if (g_error_matches (err, GST_NTP_ERROR, GST_NTP_ERROR_WRONG_VERSION)
               || g_error_matches (err, GST_NTP_ERROR, GST_NTP_ERROR_KOD_DENY)) {
             GST_ERROR_OBJECT (self, "fatal receive error: %s", err->message);
+            g_clear_error (&err);
             break;
           } else if (g_error_matches (err, GST_NTP_ERROR,
                   GST_NTP_ERROR_KOD_RATE)) {
@@ -803,13 +754,14 @@ gst_net_client_clock_thread (gpointer data)
              * our minimum poll interval. Otherwise we assume that the server
              * already told us something sensible and that this error here
              * was just a spurious error */
-            if (self->priv->last_remote_poll_interval == GST_CLOCK_TIME_NONE)
-              self->priv->minimum_update_interval *= 2;
+            if (self->last_remote_poll_interval == GST_CLOCK_TIME_NONE)
+              self->minimum_update_interval *= 2;
 
             /* And wait a bit before we send the next packet instead of
              * sending it immediately */
-            self->priv->timeout_expiration =
-                gst_util_get_timestamp () + gst_clock_get_timeout (clock);
+            self->timeout_expiration =
+                gst_util_get_timestamp () +
+                gst_clock_get_timeout (GST_CLOCK_CAST (self));
           } else {
             GST_WARNING_OBJECT (self, "receive error: %s", err->message);
           }
@@ -830,7 +782,7 @@ gst_net_client_clock_thread (gpointer data)
               GST_TIME_ARGS (new_local));
 
           /* observe_times will reset the timeout */
-          gst_net_client_clock_observe_times (self, packet->local_time,
+          gst_net_client_internal_clock_observe_times (self, packet->local_time,
               packet->remote_time, packet->remote_time, new_local);
 
           g_free (packet);
@@ -846,7 +798,7 @@ gst_net_client_clock_thread (gpointer data)
 }
 
 static gboolean
-gst_net_client_clock_start (GstNetClientClock * self)
+gst_net_client_internal_clock_start (GstNetClientInternalClock * self)
 {
   GSocketAddress *servaddr;
   GSocketAddress *myaddr;
@@ -856,24 +808,37 @@ gst_net_client_clock_start (GstNetClientClock * self)
   GError *error = NULL;
   GSocketFamily family;
   GPollFD dummy_pollfd;
+  GResolver *resolver = NULL;
+  GError *err = NULL;
 
-  g_return_val_if_fail (self->priv->address != NULL, FALSE);
-  g_return_val_if_fail (self->priv->servaddr == NULL, FALSE);
+  g_return_val_if_fail (self->address != NULL, FALSE);
+  g_return_val_if_fail (self->servaddr == NULL, FALSE);
 
   /* create target address */
-  inetaddr = g_inet_address_new_from_string (self->priv->address);
-  if (inetaddr == NULL)
-    goto bad_address;
+  inetaddr = g_inet_address_new_from_string (self->address);
+  if (inetaddr == NULL) {
+    GList *results;
+
+    resolver = g_resolver_get_default ();
+
+    results = g_resolver_lookup_by_name (resolver, self->address, NULL, &err);
+    if (!results)
+      goto failed_to_resolve;
+
+    inetaddr = G_INET_ADDRESS (g_object_ref (results->data));
+    g_resolver_free_addresses (results);
+    g_object_unref (resolver);
+  }
 
   family = g_inet_address_get_family (inetaddr);
 
-  servaddr = g_inet_socket_address_new (inetaddr, self->priv->port);
+  servaddr = g_inet_socket_address_new (inetaddr, self->port);
   g_object_unref (inetaddr);
 
   g_assert (servaddr != NULL);
 
-  GST_DEBUG_OBJECT (self, "will communicate with %s:%d", self->priv->address,
-      self->priv->port);
+  GST_DEBUG_OBJECT (self, "will communicate with %s:%d", self->address,
+      self->port);
 
   socket = g_socket_new (family, G_SOCKET_TYPE_DATAGRAM,
       G_SOCKET_PROTOCOL_UDP, &error);
@@ -902,15 +867,15 @@ gst_net_client_clock_start (GstNetClientClock * self)
 
   g_object_unref (myaddr);
 
-  self->priv->cancel = g_cancellable_new ();
-  self->priv->made_cancel_fd =
-      g_cancellable_make_pollfd (self->priv->cancel, &dummy_pollfd);
+  self->cancel = g_cancellable_new ();
+  self->made_cancel_fd =
+      g_cancellable_make_pollfd (self->cancel, &dummy_pollfd);
 
-  self->priv->socket = socket;
-  self->priv->servaddr = G_SOCKET_ADDRESS (servaddr);
+  self->socket = socket;
+  self->servaddr = G_SOCKET_ADDRESS (servaddr);
 
-  self->priv->thread = g_thread_try_new ("GstNetClientClock",
-      gst_net_client_clock_thread, self, &error);
+  self->thread = g_thread_try_new ("GstNetClientInternalClock",
+      gst_net_client_internal_clock_thread, self, &error);
 
   if (error != NULL)
     goto no_thread;
@@ -938,59 +903,481 @@ getsockname_error:
     g_object_unref (socket);
     return FALSE;
   }
-bad_address:
+failed_to_resolve:
   {
-    GST_ERROR_OBJECT (self, "inet_address_new_from_string('%s') failed",
-        self->priv->address);
+    GST_ERROR_OBJECT (self, "resolving '%s' failed: %s",
+        self->address, err->message);
+    g_clear_error (&err);
+    g_object_unref (resolver);
     return FALSE;
   }
 no_thread:
   {
     GST_ERROR_OBJECT (self, "could not create thread: %s", error->message);
-    g_object_unref (self->priv->servaddr);
-    self->priv->servaddr = NULL;
-    g_object_unref (self->priv->socket);
-    self->priv->socket = NULL;
+    g_object_unref (self->servaddr);
+    self->servaddr = NULL;
+    g_object_unref (self->socket);
+    self->socket = NULL;
     g_error_free (error);
     return FALSE;
   }
 }
 
 static void
-gst_net_client_clock_stop (GstNetClientClock * self)
+gst_net_client_internal_clock_stop (GstNetClientInternalClock * self)
 {
-  if (self->priv->thread == NULL)
+  if (self->thread == NULL)
     return;
 
   GST_INFO_OBJECT (self, "stopping...");
-  g_cancellable_cancel (self->priv->cancel);
+  g_cancellable_cancel (self->cancel);
 
-  g_thread_join (self->priv->thread);
-  self->priv->thread = NULL;
+  g_thread_join (self->thread);
+  self->thread = NULL;
 
-  if (self->priv->made_cancel_fd)
-    g_cancellable_release_fd (self->priv->cancel);
+  if (self->made_cancel_fd)
+    g_cancellable_release_fd (self->cancel);
 
-  g_object_unref (self->priv->cancel);
-  self->priv->cancel = NULL;
+  g_object_unref (self->cancel);
+  self->cancel = NULL;
 
-  g_object_unref (self->priv->servaddr);
-  self->priv->servaddr = NULL;
+  g_object_unref (self->servaddr);
+  self->servaddr = NULL;
 
-  g_object_unref (self->priv->socket);
-  self->priv->socket = NULL;
+  g_object_unref (self->socket);
+  self->socket = NULL;
 
   GST_INFO_OBJECT (self, "stopped");
 }
 
+#define GST_NET_CLIENT_CLOCK_GET_PRIVATE(obj)  \
+  (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_NET_CLIENT_CLOCK, GstNetClientClockPrivate))
+
+struct _GstNetClientClockPrivate
+{
+  GstClock *internal_clock;
+
+  GstClockTime roundtrip_limit;
+  GstClockTime minimum_update_interval;
+
+  GstClockTime base_time, internal_base_time;
+
+  gchar *address;
+  gint port;
+
+  GstBus *bus;
+
+  gboolean is_ntp;
+
+  gulong synced_id;
+};
+
+G_DEFINE_TYPE (GstNetClientClock, gst_net_client_clock, GST_TYPE_SYSTEM_CLOCK);
+
+static void gst_net_client_clock_finalize (GObject * object);
+static void gst_net_client_clock_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_net_client_clock_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_net_client_clock_constructed (GObject * object);
+
+static GstClockTime gst_net_client_clock_get_internal_time (GstClock * clock);
+
+static void
+gst_net_client_clock_class_init (GstNetClientClockClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstClockClass *clock_class;
+
+  gobject_class = G_OBJECT_CLASS (klass);
+  clock_class = GST_CLOCK_CLASS (klass);
+
+  g_type_class_add_private (klass, sizeof (GstNetClientClockPrivate));
+
+  gobject_class->finalize = gst_net_client_clock_finalize;
+  gobject_class->get_property = gst_net_client_clock_get_property;
+  gobject_class->set_property = gst_net_client_clock_set_property;
+  gobject_class->constructed = gst_net_client_clock_constructed;
+
+  g_object_class_install_property (gobject_class, PROP_ADDRESS,
+      g_param_spec_string ("address", "address",
+          "The IP address of the machine providing a time server",
+          DEFAULT_ADDRESS,
+          G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_PORT,
+      g_param_spec_int ("port", "port",
+          "The port on which the remote server is listening", 0, G_MAXUINT16,
+          DEFAULT_PORT,
+          G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_BUS,
+      g_param_spec_object ("bus", "bus",
+          "A GstBus on which to send clock status information", GST_TYPE_BUS,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  /**
+   * GstNetClientInternalClock::round-trip-limit:
+   *
+   * Maximum allowed round-trip for packets. If this property is set to a nonzero
+   * value, all packets with a round-trip interval larger than this limit will be
+   * ignored. This is useful for networks with severe and fluctuating transport
+   * delays. Filtering out these packets increases stability of the synchronization.
+   * On the other hand, the lower the limit, the higher the amount of filtered
+   * packets. Empirical tests are typically necessary to estimate a good value
+   * for the limit.
+   * If the property is set to zero, the limit is disabled.
+   *
+   * Since: 1.4
+   */
+  g_object_class_install_property (gobject_class, PROP_ROUNDTRIP_LIMIT,
+      g_param_spec_uint64 ("round-trip-limit", "round-trip limit",
+          "Maximum tolerable round-trip interval for packets, in nanoseconds "
+          "(0 = no limit)", 0, G_MAXUINT64, DEFAULT_ROUNDTRIP_LIMIT,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class, PROP_MINIMUM_UPDATE_INTERVAL,
+      g_param_spec_uint64 ("minimum-update-interval", "minimum update interval",
+          "Minimum polling interval for packets, in nanoseconds"
+          "(0 = no limit)", 0, G_MAXUINT64, DEFAULT_MINIMUM_UPDATE_INTERVAL,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class, PROP_BASE_TIME,
+      g_param_spec_uint64 ("base-time", "Base Time",
+          "Initial time that is reported before synchronization", 0,
+          G_MAXUINT64, DEFAULT_BASE_TIME,
+          G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class, PROP_INTERNAL_CLOCK,
+      g_param_spec_object ("internal-clock", "Internal Clock",
+          "Internal clock that directly slaved to the remote clock",
+          GST_TYPE_CLOCK, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
+  clock_class->get_internal_time = gst_net_client_clock_get_internal_time;
+}
+
+static void
+gst_net_client_clock_init (GstNetClientClock * self)
+{
+  GstNetClientClockPrivate *priv;
+  GstClock *clock;
+
+  self->priv = priv = GST_NET_CLIENT_CLOCK_GET_PRIVATE (self);
+
+  GST_OBJECT_FLAG_SET (self, GST_CLOCK_FLAG_CAN_SET_MASTER);
+  GST_OBJECT_FLAG_SET (self, GST_CLOCK_FLAG_NEEDS_STARTUP_SYNC);
+
+  priv->port = DEFAULT_PORT;
+  priv->address = g_strdup (DEFAULT_ADDRESS);
+
+  priv->roundtrip_limit = DEFAULT_ROUNDTRIP_LIMIT;
+  priv->minimum_update_interval = DEFAULT_MINIMUM_UPDATE_INTERVAL;
+
+  clock = gst_system_clock_obtain ();
+  priv->base_time = DEFAULT_BASE_TIME;
+  priv->internal_base_time = gst_clock_get_time (clock);
+  gst_object_unref (clock);
+}
+
+/* Must be called with clocks_lock */
+static void
+update_clock_cache (ClockCache * cache)
+{
+  GstClockTime roundtrip_limit = 0, minimum_update_interval = 0;
+  GList *l, *busses = NULL;
+
+  GST_OBJECT_LOCK (cache->clock);
+  g_list_free_full (GST_NET_CLIENT_INTERNAL_CLOCK (cache->clock)->busses,
+      (GDestroyNotify) gst_object_unref);
+
+  for (l = cache->clocks; l; l = l->next) {
+    GstNetClientClock *clock = l->data;
+
+    if (clock->priv->bus)
+      busses = g_list_prepend (busses, gst_object_ref (clock->priv->bus));
+
+    if (roundtrip_limit == 0)
+      roundtrip_limit = clock->priv->roundtrip_limit;
+    else
+      roundtrip_limit = MAX (roundtrip_limit, clock->priv->roundtrip_limit);
+
+    if (minimum_update_interval == 0)
+      minimum_update_interval = clock->priv->minimum_update_interval;
+    else
+      minimum_update_interval =
+          MIN (minimum_update_interval, clock->priv->minimum_update_interval);
+  }
+  GST_NET_CLIENT_INTERNAL_CLOCK (cache->clock)->busses = busses;
+  GST_NET_CLIENT_INTERNAL_CLOCK (cache->clock)->roundtrip_limit =
+      roundtrip_limit;
+  GST_NET_CLIENT_INTERNAL_CLOCK (cache->clock)->minimum_update_interval =
+      minimum_update_interval;
+
+  GST_OBJECT_UNLOCK (cache->clock);
+}
+
+static gboolean
+remove_clock_cache (GstClock * clock, GstClockTime time, GstClockID id,
+    gpointer user_data)
+{
+  ClockCache *cache = user_data;
+
+  G_LOCK (clocks_lock);
+  if (!cache->clocks) {
+    gst_clock_id_unref (cache->remove_id);
+    gst_object_unref (cache->clock);
+    clocks = g_list_remove (clocks, cache);
+    g_free (cache);
+  }
+  G_UNLOCK (clocks_lock);
+
+  return TRUE;
+}
+
+static void
+gst_net_client_clock_finalize (GObject * object)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+  GList *l;
+
+  if (self->priv->synced_id)
+    g_signal_handler_disconnect (self->priv->internal_clock,
+        self->priv->synced_id);
+  self->priv->synced_id = 0;
+
+  G_LOCK (clocks_lock);
+  for (l = clocks; l; l = l->next) {
+    ClockCache *cache = l->data;
+
+    if (cache->clock == self->priv->internal_clock) {
+      cache->clocks = g_list_remove (cache->clocks, self);
+
+      if (cache->clocks) {
+        update_clock_cache (cache);
+      } else {
+        GstClock *sysclock = gst_system_clock_obtain ();
+        GstClockTime time = gst_clock_get_time (sysclock) + 60 * GST_SECOND;
+
+        cache->remove_id = gst_clock_new_single_shot_id (sysclock, time);
+        gst_clock_id_wait_async (cache->remove_id, remove_clock_cache, cache,
+            NULL);
+        gst_object_unref (sysclock);
+      }
+      break;
+    }
+  }
+  G_UNLOCK (clocks_lock);
+
+  g_free (self->priv->address);
+  self->priv->address = NULL;
+
+  if (self->priv->bus != NULL) {
+    gst_object_unref (self->priv->bus);
+    self->priv->bus = NULL;
+  }
+
+  G_OBJECT_CLASS (gst_net_client_clock_parent_class)->finalize (object);
+}
+
+static void
+gst_net_client_clock_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+  gboolean update = FALSE;
+
+  switch (prop_id) {
+    case PROP_ADDRESS:
+      GST_OBJECT_LOCK (self);
+      g_free (self->priv->address);
+      self->priv->address = g_value_dup_string (value);
+      if (self->priv->address == NULL)
+        self->priv->address = g_strdup (DEFAULT_ADDRESS);
+      GST_OBJECT_UNLOCK (self);
+      break;
+    case PROP_PORT:
+      GST_OBJECT_LOCK (self);
+      self->priv->port = g_value_get_int (value);
+      GST_OBJECT_UNLOCK (self);
+      break;
+    case PROP_ROUNDTRIP_LIMIT:
+      GST_OBJECT_LOCK (self);
+      self->priv->roundtrip_limit = g_value_get_uint64 (value);
+      GST_OBJECT_UNLOCK (self);
+      update = TRUE;
+      break;
+    case PROP_MINIMUM_UPDATE_INTERVAL:
+      GST_OBJECT_LOCK (self);
+      self->priv->minimum_update_interval = g_value_get_uint64 (value);
+      GST_OBJECT_UNLOCK (self);
+      update = TRUE;
+      break;
+    case PROP_BUS:
+      GST_OBJECT_LOCK (self);
+      if (self->priv->bus)
+        gst_object_unref (self->priv->bus);
+      self->priv->bus = g_value_dup_object (value);
+      GST_OBJECT_UNLOCK (self);
+      update = TRUE;
+      break;
+    case PROP_BASE_TIME:{
+      GstClock *clock;
+
+      self->priv->base_time = g_value_get_uint64 (value);
+      clock = gst_system_clock_obtain ();
+      self->priv->internal_base_time = gst_clock_get_time (clock);
+      gst_object_unref (clock);
+      break;
+    }
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+
+  if (update && self->priv->internal_clock) {
+    GList *l;
+
+    G_LOCK (clocks_lock);
+    for (l = clocks; l; l = l->next) {
+      ClockCache *cache = l->data;
+
+      if (cache->clock == self->priv->internal_clock) {
+        update_clock_cache (cache);
+      }
+    }
+    G_UNLOCK (clocks_lock);
+  }
+}
+
+static void
+gst_net_client_clock_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+
+  switch (prop_id) {
+    case PROP_ADDRESS:
+      GST_OBJECT_LOCK (self);
+      g_value_set_string (value, self->priv->address);
+      GST_OBJECT_UNLOCK (self);
+      break;
+    case PROP_PORT:
+      g_value_set_int (value, self->priv->port);
+      break;
+    case PROP_ROUNDTRIP_LIMIT:
+      GST_OBJECT_LOCK (self);
+      g_value_set_uint64 (value, self->priv->roundtrip_limit);
+      GST_OBJECT_UNLOCK (self);
+      break;
+    case PROP_MINIMUM_UPDATE_INTERVAL:
+      GST_OBJECT_LOCK (self);
+      g_value_set_uint64 (value, self->priv->minimum_update_interval);
+      GST_OBJECT_UNLOCK (self);
+      break;
+    case PROP_BUS:
+      GST_OBJECT_LOCK (self);
+      g_value_set_object (value, self->priv->bus);
+      GST_OBJECT_UNLOCK (self);
+      break;
+    case PROP_BASE_TIME:
+      g_value_set_uint64 (value, self->priv->base_time);
+      break;
+    case PROP_INTERNAL_CLOCK:
+      g_value_set_object (value, self->priv->internal_clock);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_net_client_clock_synced_cb (GstClock * internal_clock, gboolean synced,
+    GstClock * self)
+{
+  gst_clock_set_synced (self, synced);
+}
+
+static void
+gst_net_client_clock_constructed (GObject * object)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+  GstClock *internal_clock;
+  GList *l;
+  ClockCache *cache = NULL;
+
+  G_OBJECT_CLASS (gst_net_client_clock_parent_class)->constructed (object);
+
+  G_LOCK (clocks_lock);
+  for (l = clocks; l; l = l->next) {
+    ClockCache *tmp = l->data;
+    GstNetClientInternalClock *internal_clock =
+        GST_NET_CLIENT_INTERNAL_CLOCK (tmp->clock);
+
+    if (strcmp (internal_clock->address, self->priv->address) == 0 &&
+        internal_clock->port == self->priv->port) {
+      cache = tmp;
+
+      if (cache->remove_id) {
+        gst_clock_id_unschedule (cache->remove_id);
+        cache->remove_id = NULL;
+      }
+      break;
+    }
+  }
+
+  if (!cache) {
+    cache = g_new0 (ClockCache, 1);
+
+    cache->clock =
+        g_object_new (GST_TYPE_NET_CLIENT_INTERNAL_CLOCK, "address",
+        self->priv->address, "port", self->priv->port, "is-ntp",
+        self->priv->is_ntp, NULL);
+    clocks = g_list_prepend (clocks, cache);
+
+    /* Not actually leaked but is cached for a while before being disposed,
+     * see gst_net_client_clock_finalize, so pretend it is to not confuse
+     * tests. */
+    GST_OBJECT_FLAG_SET (cache->clock, GST_OBJECT_FLAG_MAY_BE_LEAKED);
+  }
+
+  cache->clocks = g_list_prepend (cache->clocks, self);
+
+  GST_OBJECT_LOCK (cache->clock);
+  if (gst_clock_is_synced (cache->clock))
+    gst_clock_set_synced (GST_CLOCK (self), TRUE);
+  self->priv->synced_id =
+      g_signal_connect (cache->clock, "synced",
+      G_CALLBACK (gst_net_client_clock_synced_cb), self);
+  GST_OBJECT_UNLOCK (cache->clock);
+
+  G_UNLOCK (clocks_lock);
+
+  self->priv->internal_clock = internal_clock = cache->clock;
+
+  /* all systems go, cap'n */
+}
+
+static GstClockTime
+gst_net_client_clock_get_internal_time (GstClock * clock)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (clock);
+
+  if (!gst_clock_is_synced (self->priv->internal_clock)) {
+    GstClockTime now = gst_clock_get_internal_time (self->priv->internal_clock);
+    return gst_clock_adjust_with_calibration (self->priv->internal_clock, now,
+        self->priv->internal_base_time, self->priv->base_time, 1, 1);
+  }
+
+  return gst_clock_get_time (self->priv->internal_clock);
+}
+
 /**
  * gst_net_client_clock_new:
  * @name: a name for the clock
- * @remote_address: the address of the remote clock provider
+ * @remote_address: the address or hostname of the remote clock provider
  * @remote_port: the port of the remote clock provider
  * @base_time: initial time of the clock
  *
- * Create a new #GstNetClientClock that will report the time
+ * Create a new #GstNetClientInternalClock that will report the time
  * provided by the #GstNetTimeProvider on @remote_address and 
  * @remote_port.
  *
@@ -1001,7 +1388,7 @@ GstClock *
 gst_net_client_clock_new (const gchar * name, const gchar * remote_address,
     gint remote_port, GstClockTime base_time)
 {
-  GstNetClientClock *ret;
+  GstClock *ret;
 
   g_return_val_if_fail (remote_address != NULL, NULL);
   g_return_val_if_fail (remote_port > 0, NULL);
@@ -1011,7 +1398,7 @@ gst_net_client_clock_new (const gchar * name, const gchar * remote_address,
   ret = g_object_new (GST_TYPE_NET_CLIENT_CLOCK, "address", remote_address,
       "port", remote_port, "base-time", base_time, NULL);
 
-  return (GstClock *) ret;
+  return ret;
 }
 
 G_DEFINE_TYPE (GstNtpClock, gst_ntp_clock, GST_TYPE_NET_CLIENT_CLOCK);
@@ -1030,7 +1417,7 @@ gst_ntp_clock_init (GstNtpClock * self)
 /**
  * gst_ntp_clock_new:
  * @name: a name for the clock
- * @remote_address: the address of the remote clock provider
+ * @remote_address: the address or hostname of the remote clock provider
  * @remote_port: the port of the remote clock provider
  * @base_time: initial time of the clock
  *
@@ -1039,12 +1426,14 @@ gst_ntp_clock_init (GstNtpClock * self)
  *
  * Returns: a new #GstClock that receives a time from the remote
  * clock.
+ *
+ * Since: 1.6
  */
 GstClock *
 gst_ntp_clock_new (const gchar * name, const gchar * remote_address,
     gint remote_port, GstClockTime base_time)
 {
-  GstNetClientClock *ret;
+  GstClock *ret;
 
   g_return_val_if_fail (remote_address != NULL, NULL);
   g_return_val_if_fail (remote_port > 0, NULL);
@@ -1054,5 +1443,5 @@ gst_ntp_clock_new (const gchar * name, const gchar * remote_address,
   ret = g_object_new (GST_TYPE_NTP_CLOCK, "address", remote_address,
       "port", remote_port, "base-time", base_time, NULL);
 
-  return (GstClock *) ret;
+  return ret;
 }