gstrtpsession: Implement a number of feedback packet statistics

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=711693

gst/rtpmanager/gstrtpsession.c

@@ -218,6 +218,7 @@ enum
   PROP_USE_PIPELINE_CLOCK,
   PROP_RTCP_MIN_INTERVAL,
   PROP_PROBATION,
+  PROP_STATS,
   PROP_LAST
 };
 
@@ -251,6 +252,8 @@ struct _GstRtpSessionPrivate
   GstClockTime send_latency;
 
   gboolean use_pipeline_clock;
+
+  guint rtx_count;
 };
 
 /* callbacks to handle actions from the session manager */
@@ -305,6 +308,8 @@ static gboolean gst_rtp_session_setcaps_send_rtp (GstPad * pad,
 
 static void gst_rtp_session_clear_pt_map (GstRtpSession * rtpsession);
 
+static GstStructure *gst_rtp_session_create_stats (GstRtpSession * rtpsession);
+
 static guint gst_rtp_session_signals[LAST_SIGNAL] = { 0 };
 
 static void
@@ -605,6 +610,26 @@ gst_rtp_session_class_init (GstRtpSessionClass * klass)
           0, G_MAXUINT, DEFAULT_PROBATION,
           G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
+  /**
+   * GstRtpSession::stats:
+   *
+   * Various session statistics. This property returns a GstStructure
+   * with name application/x-rtp-session-stats with the following fields:
+   *
+   *  "rtx-count"       G_TYPE_UINT   The number of retransmission events
+   *      received from downstream (in receiver mode)
+   *  "rtx-drop-count"  G_TYPE_UINT   The number of retransmission events
+   *      dropped (due to bandwidth constraints)
+   *  "sent-nack-count" G_TYPE_UINT   Number of NACKs sent
+   *  "recv-nack-count" G_TYPE_UINT   Number of NACKs received
+   *
+   * Since: 1.3.1
+   */
+  g_object_class_install_property (gobject_class, PROP_STATS,
+      g_param_spec_boxed ("stats", "Statistics",
+          "Various statistics", GST_TYPE_STRUCTURE,
+          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
   gstelement_class->change_state =
       GST_DEBUG_FUNCPTR (gst_rtp_session_change_state);
   gstelement_class->request_new_pad =
@@ -678,6 +703,8 @@ gst_rtp_session_init (GstRtpSession * rtpsession)
   gst_segment_init (&rtpsession->send_rtp_seg, GST_FORMAT_UNDEFINED);
 
   rtpsession->priv->thread_stopped = TRUE;
+
+  rtpsession->priv->rtx_count = 0;
 }
 
 static void
@@ -788,12 +815,27 @@ gst_rtp_session_get_property (GObject * object, guint prop_id,
     case PROP_PROBATION:
       g_object_get_property (G_OBJECT (priv->session), "probation", value);
       break;
+    case PROP_STATS:
+      g_value_take_boxed (value, gst_rtp_session_create_stats (rtpsession));
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }
 
+static GstStructure *
+gst_rtp_session_create_stats (GstRtpSession * rtpsession)
+{
+  GstStructure *s;
+
+  g_object_get (rtpsession->priv->session, "stats", &s, NULL);
+  gst_structure_set (s, "rtx-count", G_TYPE_UINT, rtpsession->priv->rtx_count,
+      NULL);
+
+  return s;
+}
+
 static void
 get_current_times (GstRtpSession * rtpsession, GstClockTime * running_time,
     guint64 * ntpnstime)
@@ -1511,6 +1553,10 @@ gst_rtp_session_event_recv_rtp_src (GstPad * pad, GstObject * parent,
         GstClockTime running_time;
         guint seqnum, delay, deadline, max_delay;
 
+        GST_RTP_SESSION_LOCK (rtpsession);
+        rtpsession->priv->rtx_count++;
+        GST_RTP_SESSION_UNLOCK (rtpsession);
+
         if (!gst_structure_get_clock_time (s, "running-time", &running_time))
           running_time = -1;
         if (!gst_structure_get_uint (s, "ssrc", &ssrc))

gst/rtpmanager/rtpsession.c

@@ -86,6 +86,7 @@ enum
   PROP_RTCP_FEEDBACK_RETENTION_WINDOW,
   PROP_RTCP_IMMEDIATE_FEEDBACK_THRESHOLD,
   PROP_PROBATION,
+  PROP_STATS,
   PROP_LAST
 };
 
@@ -442,6 +443,24 @@ rtp_session_class_init (RTPSessionClass * klass)
           0, G_MAXUINT, DEFAULT_PROBATION,
           G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
+  /**
+   * RTPSession::stats:
+   *
+   * Various session statistics. This property returns a GstStructure
+   * with name application/x-rtp-session-stats with the following fields:
+   *
+   *  "rtx-drop-count"  G_TYPE_UINT   The number of retransmission events
+   *      dropped (due to bandwidth constraints)
+   *  "sent-nack-count" G_TYPE_UINT   Number of NACKs sent
+   *  "recv-nack-count" G_TYPE_UINT   Number of NACKs received
+   *
+   * Since: 1.3.1
+   */
+  g_object_class_install_property (gobject_class, PROP_STATS,
+      g_param_spec_boxed ("stats", "Statistics",
+          "Various statistics", GST_TYPE_STRUCTURE,
+          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
   klass->get_source_by_ssrc =
       GST_DEBUG_FUNCPTR (rtp_session_get_source_by_ssrc);
   klass->send_rtcp = GST_DEBUG_FUNCPTR (rtp_session_send_rtcp);
@@ -563,6 +582,19 @@ rtp_session_create_sources (RTPSession * sess)
   return res;
 }
 
+static GstStructure *
+rtp_session_create_stats (RTPSession * sess)
+{
+  GstStructure *s;
+
+  s = gst_structure_new ("application/x-rtp-session-stats",
+      "rtx-drop-count", G_TYPE_UINT, sess->stats.nacks_dropped,
+      "sent-nack-count", G_TYPE_UINT, sess->stats.nacks_sent,
+      "recv-nack-count", G_TYPE_UINT, sess->stats.nacks_received, NULL);
+
+  return s;
+}
+
 static void
 rtp_session_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
@@ -684,6 +716,9 @@ rtp_session_get_property (GObject * object, guint prop_id,
     case PROP_PROBATION:
       g_value_set_uint (value, sess->probation);
       break;
+    case PROP_STATS:
+      g_value_take_boxed (value, rtp_session_create_stats (sess));
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -2260,6 +2295,8 @@ rtp_session_process_feedback (RTPSession * sess, GstRTCPPacket * packet,
       GST_BUFFER_TIMESTAMP (fci_buffer) = pinfo->running_time;
     }
 
+    sess->stats.nacks_received++;
+
     RTP_SESSION_UNLOCK (sess);
     g_signal_emit (sess, rtp_session_signals[SIGNAL_ON_FEEDBACK_RTCP], 0,
         type, fbtype, sender_ssrc, media_ssrc, fci_buffer);
@@ -2771,6 +2808,7 @@ typedef struct
   gboolean is_early;
   gboolean may_suppress;
   GQueue output;
+  guint nacked_seqnums;
 } ReportData;
 
 static void
@@ -3000,6 +3038,7 @@ session_nack (const gchar * key, RTPSource * source, ReportData * data)
   for (i = 0; i < n_nacks; i++) {
     GST_WRITE_UINT32_BE (fci_data, nacks[i]);
     fci_data += 4;
+    data->nacked_seqnums++;
   }
 
   rtp_source_clear_nacks (source);
@@ -3417,6 +3456,7 @@ rtp_session_on_timeout (RTPSession * sess, GstClockTime current_time,
   data.running_time = running_time;
   data.num_to_report = 0;
   data.may_suppress = FALSE;
+  data.nacked_seqnums = 0;
   g_queue_init (&data.output);
 
   RTP_SESSION_LOCK (sess);
@@ -3492,10 +3532,12 @@ done:
       result =
           sess->callbacks.send_rtcp (sess, source, buffer, output->is_bye,
           sess->send_rtcp_user_data);
+      sess->stats.nacks_sent += data.nacked_seqnums;
     } else {
       GST_DEBUG ("freeing packet callback: %p"
           " do_not_suppress: %d may_suppress: %d",
           sess->callbacks.send_rtcp, do_not_suppress, data.may_suppress);
+      sess->stats.nacks_dropped += data.nacked_seqnums;
       gst_buffer_unref (buffer);
     }
     g_object_unref (source);

gst/rtpmanager/rtpstats.c

@@ -31,6 +31,9 @@ rtp_stats_init_defaults (RTPSessionStats * stats)
   rtp_stats_set_bandwidths (stats, -1, -1, -1, -1);
   stats->min_interval = RTP_STATS_MIN_INTERVAL;
   stats->bye_timeout = RTP_STATS_BYE_TIMEOUT;
+  stats->nacks_dropped = 0;
+  stats->nacks_sent = 0;
+  stats->nacks_received = 0;
 }
 
 /**

gst/rtpmanager/rtpstats.h

@@ -205,6 +205,9 @@ typedef struct {
   guint         active_sources;
   guint         avg_rtcp_packet_size;
   guint         bye_members;
+  guint         nacks_dropped;
+  guint         nacks_sent;
+  guint         nacks_received;
 } RTPSessionStats;
 
 void           rtp_stats_init_defaults              (RTPSessionStats *stats);