Пример #1
0
static void
gst_clock_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstClock *clock;
  GstClockPrivate *priv;

  clock = GST_CLOCK (object);
  priv = clock->priv;

  switch (prop_id) {
    case PROP_WINDOW_SIZE:
      GST_CLOCK_SLAVE_LOCK (clock);
      g_value_set_int (value, priv->window_size);
      GST_CLOCK_SLAVE_UNLOCK (clock);
      break;
    case PROP_WINDOW_THRESHOLD:
      GST_CLOCK_SLAVE_LOCK (clock);
      g_value_set_int (value, priv->window_threshold);
      GST_CLOCK_SLAVE_UNLOCK (clock);
      break;
    case PROP_TIMEOUT:
      g_value_set_uint64 (value, gst_clock_get_timeout (clock));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}
Пример #2
0
static void
gst_net_client_clock_observe_times (GstNetClientClock * self,
    GstClockTime local_1, GstClockTime remote, GstClockTime local_2)
{
  GstClockTime current_timeout;
  GstClockTime local_avg;
  gdouble r_squared;
  GstClock *clock;

  if (local_2 < local_1)
    goto bogus_observation;

  local_avg = (local_2 + local_1) / 2;

  clock = GST_CLOCK_CAST (self);

  if (gst_clock_add_observation (GST_CLOCK (self), local_avg, remote,
          &r_squared)) {
    /* geto formula */
    current_timeout = (1e-3 / (1 - MIN (r_squared, 0.99999))) * GST_SECOND;
    current_timeout = MIN (current_timeout, gst_clock_get_timeout (clock));
  } else {
    current_timeout = 0;
  }

  GST_INFO ("next timeout: %" GST_TIME_FORMAT, GST_TIME_ARGS (current_timeout));
  self->priv->timeout_expiration = gst_util_get_timestamp () + current_timeout;

  return;

bogus_observation:
  {
    GST_WARNING_OBJECT (self, "time packet receive time < send time (%"
        GST_TIME_FORMAT " < %" GST_TIME_FORMAT ")", GST_TIME_ARGS (local_1),
        GST_TIME_ARGS (local_2));
    return;
  }
}
Пример #3
0
static gpointer
gst_net_client_clock_thread (gpointer data)
{
  GstNetClientClock *self = data;
  GstNetTimePacket *packet;
  GSocket *socket = self->priv->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;
    GstClockTime now = gst_util_get_timestamp ();
    gint64 socket_timeout;

    if (now >= expiration_time || (expiration_time - now) <= GST_MSECOND) {
      socket_timeout = 0;
    } else {
      socket_timeout = (expiration_time - now) / GST_USECOND;
    }

    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)) {
      /* cancelled, timeout or error */
      if (err->code == G_IO_ERROR_CANCELLED) {
        GST_INFO_OBJECT (self, "cancelled");
        g_clear_error (&err);
        break;
      } else if (err->code == G_IO_ERROR_TIMED_OUT) {
        /* timed out, let's send another packet */
        GST_DEBUG_OBJECT (self, "timed out");

        packet = gst_net_time_packet_new (NULL);

        packet->local_time = gst_clock_get_internal_time (GST_CLOCK (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);

        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);
      } else {
        GST_DEBUG_OBJECT (self, "socket error: %s", err->message);
        g_usleep (G_USEC_PER_SEC / 10); /* throttle */
      }
      g_clear_error (&err);
    } else {
      GstClockTime new_local;

      /* got packet */

      new_local = gst_clock_get_internal_time (GST_CLOCK (self));

      packet = gst_net_time_packet_receive (socket, NULL, &err);

      if (packet != NULL) {
        GST_LOG_OBJECT (self, "got packet back");
        GST_LOG_OBJECT (self, "local_1 = %" GST_TIME_FORMAT,
            GST_TIME_ARGS (packet->local_time));
        GST_LOG_OBJECT (self, "remote = %" GST_TIME_FORMAT,
            GST_TIME_ARGS (packet->remote_time));
        GST_LOG_OBJECT (self, "local_2 = %" GST_TIME_FORMAT,
            GST_TIME_ARGS (new_local));

        /* observe_times will reset the timeout */
        gst_net_client_clock_observe_times (self, packet->local_time,
            packet->remote_time, new_local);

        g_free (packet);
      } else if (err != NULL) {
        GST_WARNING_OBJECT (self, "receive error: %s", err->message);
        g_clear_error (&err);
      }
    }
  }

  GST_INFO_OBJECT (self, "shutting down net client clock thread");
  return NULL;
}
Пример #4
0
static gpointer
gst_net_client_clock_thread (gpointer data)
{
  GstNetClientClock *self = data;
  GstNetTimePacket *packet;
  GMainContext *ctx;
  GSourceFuncs funcs = { NULL, };
  GSource *source;
  GIOCondition cond;
  gboolean timeout;
  GSocket *socket = self->priv->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);

  ctx = g_main_context_new ();

  source = g_socket_create_source (socket, G_IO_IN, self->priv->cancel);
  g_source_set_name (source, "GStreamer net client clock thread socket");
  g_source_set_callback (source, (GSourceFunc) gst_net_client_clock_socket_cb,
      &cond, NULL);
  g_source_attach (source, ctx);
  g_source_unref (source);

  /* GSocket only support second granularity for timeouts, so roll our own
   * timeout source (so we don't have to create a new source whenever the
   * timeout changes, as we would have to do with the default timeout source) */
  funcs.prepare = gst_net_client_clock_timeout_source_prepare;
  funcs.check = gst_net_client_clock_timeout_source_check;
  funcs.dispatch = gst_net_client_clock_timeout_source_dispatch;
  funcs.finalize = NULL;
  source = g_source_new (&funcs, sizeof (GstNetClientClockTimeoutSource));
  ((GstNetClientClockTimeoutSource *) source)->clock = self;
  ((GstNetClientClockTimeoutSource *) source)->p_timeout = &timeout;
  g_source_set_name (source, "GStreamer net client clock timeout");
  g_source_attach (source, ctx);
  g_source_unref (source);

  while (!g_cancellable_is_cancelled (self->priv->cancel)) {
    cond = 0;
    timeout = FALSE;
    g_main_context_iteration (ctx, TRUE);

    if (g_cancellable_is_cancelled (self->priv->cancel))
      break;

    if (timeout) {
      /* timed out, let's send another packet */
      GST_DEBUG_OBJECT (self, "timed out");

      packet = gst_net_time_packet_new (NULL);

      packet->local_time = gst_clock_get_internal_time (GST_CLOCK (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);

      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);
      continue;
    }

    /* got data to read? */
    if ((cond & G_IO_IN)) {
      GstClockTime new_local;

      new_local = gst_clock_get_internal_time (GST_CLOCK (self));

      packet = gst_net_time_packet_receive (socket, NULL, &err);

      if (err != NULL) {
        GST_WARNING_OBJECT (self, "receive error: %s", err->message);
        g_error_free (err);
        err = NULL;
        continue;
      }

      GST_LOG_OBJECT (self, "got packet back");
      GST_LOG_OBJECT (self, "local_1 = %" GST_TIME_FORMAT,
          GST_TIME_ARGS (packet->local_time));
      GST_LOG_OBJECT (self, "remote = %" GST_TIME_FORMAT,
          GST_TIME_ARGS (packet->remote_time));
      GST_LOG_OBJECT (self, "local_2 = %" GST_TIME_FORMAT,
          GST_TIME_ARGS (new_local));

      /* observe_times will reset the timeout */
      gst_net_client_clock_observe_times (self, packet->local_time,
          packet->remote_time, new_local);

      g_free (packet);
      continue;
    }

    if ((cond & (G_IO_ERR | G_IO_HUP))) {
      GST_DEBUG_OBJECT (self, "socket error?! %s", g_strerror (errno));
      g_usleep (G_USEC_PER_SEC / 10);
      continue;
    }
  }

  GST_INFO_OBJECT (self, "shutting down net client clock thread");
  g_main_context_unref (ctx);
  return NULL;
}
static gpointer
gst_net_client_internal_clock_thread (gpointer data)
{
  GstNetClientInternalClock *self = data;
  GSocket *socket = self->socket;
  GError *err = NULL;

  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->cancel)) {
    GstClockTime expiration_time = self->timeout_expiration;
    GstClockTime now = gst_util_get_timestamp ();
    gint64 socket_timeout;

    if (now >= expiration_time || (expiration_time - now) <= GST_MSECOND) {
      socket_timeout = 0;
    } else {
      socket_timeout = (expiration_time - now) / GST_USECOND;
    }

    GST_TRACE_OBJECT (self, "timeout: %" G_GINT64_FORMAT "us", socket_timeout);

    if (!g_socket_condition_timed_wait (socket, G_IO_IN, socket_timeout,
            self->cancel, &err)) {
      /* cancelled, timeout or error */
      if (err->code == G_IO_ERROR_CANCELLED) {
        GST_INFO_OBJECT (self, "cancelled");
        g_clear_error (&err);
        break;
      } else if (err->code == G_IO_ERROR_TIMED_OUT) {
        /* timed out, let's send another packet */
        GST_DEBUG_OBJECT (self, "timed out");

        if (self->is_ntp) {
          GstNtpPacket *packet;

          packet = gst_ntp_packet_new (NULL, NULL);

          packet->transmit_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->transmit_time));

          gst_ntp_packet_send (packet, self->socket, self->servaddr, NULL);

          g_free (packet);
        } else {
          GstNetTimePacket *packet;

          packet = gst_net_time_packet_new (NULL);

          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->socket, self->servaddr, NULL);

          g_free (packet);
        }

        /* reset timeout (but are expecting a response sooner anyway) */
        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 */
      }
      g_clear_error (&err);
    } else {
      GstClockTime new_local;

      /* got packet */

      new_local = gst_clock_get_internal_time (GST_CLOCK_CAST (self));

      if (self->is_ntp) {
        GstNtpPacket *packet;

        packet = gst_ntp_packet_receive (socket, NULL, &err);

        if (packet != NULL) {
          GST_LOG_OBJECT (self, "got packet back");
          GST_LOG_OBJECT (self, "local_1 = %" GST_TIME_FORMAT,
              GST_TIME_ARGS (packet->origin_time));
          GST_LOG_OBJECT (self, "remote_1 = %" GST_TIME_FORMAT,
              GST_TIME_ARGS (packet->receive_time));
          GST_LOG_OBJECT (self, "remote_2 = %" GST_TIME_FORMAT,
              GST_TIME_ARGS (packet->transmit_time));
          GST_LOG_OBJECT (self, "local_2 = %" GST_TIME_FORMAT,
              GST_TIME_ARGS (new_local));
          GST_LOG_OBJECT (self, "poll_interval = %" GST_TIME_FORMAT,
              GST_TIME_ARGS (packet->poll_interval));

          /* Remember the last poll interval we ever got from the server */
          if (packet->poll_interval != GST_CLOCK_TIME_NONE)
            self->last_remote_poll_interval = packet->poll_interval;

          /* observe_times will reset the timeout */
          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)) {
            GST_WARNING_OBJECT (self, "need to limit rate");

            /* If the server did not tell us a poll interval before, double
             * 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->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->timeout_expiration =
                gst_util_get_timestamp () +
                gst_clock_get_timeout (GST_CLOCK_CAST (self));
          } else {
            GST_WARNING_OBJECT (self, "receive error: %s", err->message);
          }
          g_clear_error (&err);
        }
      } else {
        GstNetTimePacket *packet;

        packet = gst_net_time_packet_receive (socket, NULL, &err);

        if (packet != NULL) {
          GST_LOG_OBJECT (self, "got packet back");
          GST_LOG_OBJECT (self, "local_1 = %" GST_TIME_FORMAT,
              GST_TIME_ARGS (packet->local_time));
          GST_LOG_OBJECT (self, "remote = %" GST_TIME_FORMAT,
              GST_TIME_ARGS (packet->remote_time));
          GST_LOG_OBJECT (self, "local_2 = %" GST_TIME_FORMAT,
              GST_TIME_ARGS (new_local));

          /* observe_times will reset the timeout */
          gst_net_client_internal_clock_observe_times (self, packet->local_time,
              packet->remote_time, packet->remote_time, new_local);

          g_free (packet);
        } else if (err != NULL) {
          GST_WARNING_OBJECT (self, "receive error: %s", err->message);
          g_clear_error (&err);
        }
      }
    }
  }
  GST_INFO_OBJECT (self, "shutting down net client clock thread");
  return NULL;
}
static void
gst_net_client_internal_clock_observe_times (GstNetClientInternalClock * self,
    GstClockTime local_1, GstClockTime remote_1, GstClockTime remote_2,
    GstClockTime local_2)
{
  GstClockTime current_timeout = 0;
  GstClockTime local_avg, remote_avg;
  gdouble r_squared;
  GstClock *clock;
  GstClockTime rtt, rtt_limit, min_update_interval;
  /* Use for discont tracking */
  GstClockTime time_before = 0;
  GstClockTime min_guess = 0;
  GstClockTimeDiff time_discont = 0;
  gboolean synched, now_synched;
  GstClockTime internal_time, external_time, rate_num, rate_den;
  GstClockTime orig_internal_time, orig_external_time, orig_rate_num,
      orig_rate_den;
  GstClockTime max_discont;
  GstClockTime last_rtts[MEDIAN_PRE_FILTERING_WINDOW];
  GstClockTime median;
  gint i;

  GST_OBJECT_LOCK (self);
  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->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->minimum_update_interval;
  GST_OBJECT_UNLOCK (self);

  if (local_2 < local_1) {
    GST_LOG_OBJECT (self, "Dropping observation: receive time %" GST_TIME_FORMAT
        " < send time %" GST_TIME_FORMAT, GST_TIME_ARGS (local_1),
        GST_TIME_ARGS (local_2));
    goto bogus_observation;
  }

  if (remote_2 < remote_1) {
    GST_LOG_OBJECT (self,
        "Dropping observation: remote receive time %" GST_TIME_FORMAT
        " < send time %" GST_TIME_FORMAT, GST_TIME_ARGS (remote_1),
        GST_TIME_ARGS (remote_2));
    goto bogus_observation;
  }

  /* The round trip time is (assuming symmetric path delays)
   * delta = (local_2 - local_1) - (remote_2 - remote_1)
   */

  rtt = GST_CLOCK_DIFF (local_1, local_2) - GST_CLOCK_DIFF (remote_1, remote_2);

  if ((rtt_limit > 0) && (rtt > rtt_limit)) {
    GST_LOG_OBJECT (self,
        "Dropping observation: RTT %" GST_TIME_FORMAT " > limit %"
        GST_TIME_FORMAT, GST_TIME_ARGS (rtt), GST_TIME_ARGS (rtt_limit));
    goto bogus_observation;
  }

  for (i = 1; i < MEDIAN_PRE_FILTERING_WINDOW; i++)
    self->last_rtts[i - 1] = self->last_rtts[i];
  self->last_rtts[i - 1] = rtt;

  if (self->last_rtts_missing) {
    self->last_rtts_missing--;
  } else {
    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);

    median = last_rtts[MEDIAN_PRE_FILTERING_WINDOW / 2];

    /* FIXME: We might want to use something else here, like only allowing
     * things in the interquartile range, or also filtering away delays that
     * are too small compared to the median. This here worked well enough
     * in tests so far.
     */
    if (rtt > 2 * median) {
      GST_LOG_OBJECT (self,
          "Dropping observation, long RTT %" GST_TIME_FORMAT " > 2 * median %"
          GST_TIME_FORMAT, GST_TIME_ARGS (rtt), GST_TIME_ARGS (median));
      goto bogus_observation;
    }
  }

  /* 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 (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
    self->rtt_avg = (15 * self->rtt_avg + rtt) / 16;

  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 (self->rtt_avg));
    goto bogus_observation;
  }

  /* The difference between the local and remote clock (again assuming
   * symmetric path delays):
   *
   * local_1 + delta / 2 - remote_1 = theta
   * or
   * local_2 - delta / 2 - remote_2 = theta
   *
   * which gives after some simple algebraic transformations:
   *
   *         (remote_1 - local_1) + (remote_2 - local_2)
   * theta = -------------------------------------------
   *                              2
   *
   *
   * Thus remote time at local_avg is equal to:
   *
   * local_avg + theta =
   *
   * local_1 + local_2   (remote_1 - local_1) + (remote_2 - local_2)
   * ----------------- + -------------------------------------------
   *         2                                2
   *
   * =
   *
   * remote_1 + remote_2
   * ------------------- = remote_avg
   *          2
   *
   * We use this for our clock estimation, i.e. local_avg at remote clock
   * being the same as remote_avg.
   */

  local_avg = (local_2 + local_1) / 2;
  remote_avg = (remote_2 + remote_1) / 2;

  GST_LOG_OBJECT (self,
      "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_CAST (self), &orig_internal_time,
      &orig_external_time, &orig_rate_num, &orig_rate_den);
  internal_time = orig_internal_time;
  external_time = orig_external_time;
  rate_num = orig_rate_num;
  rate_den = orig_rate_den;

  min_guess =
      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_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 = self->rtt_avg / 4;

  /* If the remote observation was within a max_discont window around our min/max estimates, we're synched */
  synched =
      (GST_CLOCK_DIFF (remote_avg, min_guess) < (GstClockTimeDiff) (max_discont)
      && GST_CLOCK_DIFF (time_before,
          remote_avg) < (GstClockTimeDiff) (max_discont));

  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_CAST (self), local_2,
            internal_time, external_time, rate_num, rate_den));

    /* If we were in sync with the remote clock, clamp the allowed
     * discontinuity to within quarter of one RTT. In sync means our send/receive estimates
     * of remote time correctly windowed the actual remote time observation */
    if (synched && ABS (time_discont) > max_discont) {
      GstClockTimeDiff offset;
      GST_DEBUG_OBJECT (clock,
          "Too large a discont, clamping to 1/4 average RTT = %"
          GST_TIME_FORMAT, GST_TIME_ARGS (max_discont));
      if (time_discont > 0) {   /* Too large a forward step - add a -ve offset */
        offset = max_discont - time_discont;
        if (-offset > external_time)
          external_time = 0;
        else
          external_time += offset;
      } else {                  /* Too large a backward step - add a +ve offset */
        offset = -(max_discont + time_discont);
        external_time += offset;
      }

      time_discont += offset;
    }

    /* 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_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_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 || 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 (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;
      external_time = orig_external_time;
      rate_num = orig_rate_num;
      rate_den = orig_rate_den;
      time_discont = 0;
      self->skipped_updates++;
    }
  }

  /* Limit the polling to at most one per minimum_update_interval */
  if (rtt < min_update_interval)
    current_timeout = MAX (min_update_interval - rtt, current_timeout);

  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, self->rtt_avg,
        "local", G_TYPE_UINT64, local_avg,
        "remote", G_TYPE_UINT64, remote_avg,
        "discontinuity", G_TYPE_INT64, time_discont,
        "remote-min-estimate", G_TYPE_UINT64, min_guess,
        "remote-max-estimate", G_TYPE_UINT64, time_before,
        "remote-min-error", G_TYPE_INT64, GST_CLOCK_DIFF (remote_avg,
            min_guess), "remote-max-error", G_TYPE_INT64,
        GST_CLOCK_DIFF (remote_avg, time_before), "request-send", G_TYPE_UINT64,
        local_1, "request-receive", G_TYPE_UINT64, local_2, "r-squared",
        G_TYPE_DOUBLE, r_squared, "timeout", G_TYPE_UINT64, current_timeout,
        "internal-time", G_TYPE_UINT64, internal_time, "external-time",
        G_TYPE_UINT64, external_time, "rate-num", G_TYPE_UINT64, rate_num,
        "rate-den", G_TYPE_UINT64, rate_den, "rate", G_TYPE_DOUBLE,
        (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);

    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->timeout_expiration = gst_util_get_timestamp () + current_timeout;

  return;

bogus_observation:
  /* Schedule a new packet again soon */
  self->timeout_expiration = gst_util_get_timestamp () + (GST_SECOND / 4);
  return;
}