1 files changed, 111 insertions, 0 deletions
diff --git a/gst/rtpmanager/rtpstats.c b/gst/rtpmanager/rtpstats.c
new file mode 100644
index 00000000..b9076eac
--- /dev/null
+++ b/gst/rtpmanager/rtpstats.c
@@ -0,0 +1,111 @@
+/* GStreamer
+ * Copyright (C) <2007> Wim Taymans <wim@fluendo.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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "rtpstats.h"
+
+/**
+ * rtp_stats_init_defaults:
+ * @stats: an #RTPSessionStats struct
+ *
+ * Initialize @stats with its default values.
+ */
+void
+rtp_stats_init_defaults (RTPSessionStats * stats)
+{
+  stats->bandwidth = RTP_STATS_BANDWIDTH;
+  stats->sender_fraction = RTP_STATS_SENDER_FRACTION;
+  stats->receiver_fraction = RTP_STATS_RECEIVER_FRACTION;
+  stats->rtcp_bandwidth = RTP_STATS_RTCP_BANDWIDTH;
+  stats->min_interval = RTP_STATS_MIN_INTERVAL;
+}
+
+/**
+ * rtp_stats_calculate_rtcp_interval:
+ * @stats: an #RTPSessionStats struct
+ * 
+ * Calculate the RTCP interval. The result of this function is the amount of
+ * time to wait (in seconds) before sender a new RTCP message.
+ *
+ * Returns: the RTCP interval.
+ */
+gdouble
+rtp_stats_calculate_rtcp_interval (RTPSessionStats * stats, gboolean sender)
+{
+  gdouble active, senders, receivers, sfraction;
+  gboolean avg_rtcp;
+  gdouble interval;
+
+  active = stats->active_sources;
+  /* Try to avoid division by zero */
+  if (stats->active_sources == 0)
+    active += 1.0;
+
+  senders = (gdouble) stats->sender_sources;
+  receivers = (gdouble) (active - senders);
+  avg_rtcp = (gdouble) stats->avg_rtcp_packet_size;
+
+  sfraction = senders / active;
+
+  GST_DEBUG ("senders: %f, receivers %f, avg_rtcp %f, sfraction %f",
+      senders, receivers, avg_rtcp, sfraction);
+
+  if (sfraction <= stats->sender_fraction) {
+    if (sender) {
+      interval =
+          (avg_rtcp * senders) / (stats->sender_fraction *
+          stats->rtcp_bandwidth);
+    } else {
+      interval =
+          (avg_rtcp * receivers) / ((1.0 -
+              stats->sender_fraction) * stats->rtcp_bandwidth);
+    }
+  } else {
+    interval = (avg_rtcp * active) / stats->rtcp_bandwidth;
+  }
+
+  if (interval < stats->min_interval)
+    interval = stats->min_interval;
+
+  if (!stats->sent_rtcp)
+    interval /= 2.0;
+
+  return interval;
+}
+
+/**
+ * rtp_stats_calculate_rtcp_interval:
+ * @stats: an #RTPSessionStats struct
+ * @interval: an RTCP interval
+ * 
+ * Apply a random jitter to the @interval. @interval is typically obtained with
+ * rtp_stats_calculate_rtcp_interval().
+ *
+ * Returns: the new RTCP interval.
+ */
+gdouble
+rtp_stats_add_rtcp_jitter (RTPSessionStats * stats, gdouble interval)
+{
+  /* see RFC 3550 p 30 
+   * To compensate for "unconditional reconsideration" converging to a
+   * value below the intended average.
+   */
+#define COMPENSATION  (2.71828 - 1.5);
+
+  return (interval * g_random_double_range (0.5, 1.5)) / COMPENSATION;
+}