rtpbasepayload: Add statistics property

This property allows for an atomically retrieved set of properties that
can e.g. be used to generate RTP-Info headers.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=719415

gst-libs/gst/rtp/gstrtpbasepayload.c

@@ -93,6 +93,7 @@ enum
   PROP_SEQNUM,
   PROP_PERFECT_RTPTIME,
   PROP_PTIME_MULTIPLE,
+  PROP_STATS,
   PROP_LAST
 };
 
@@ -243,6 +244,37 @@ gst_rtp_base_payload_class_init (GstRTPBasePayloadClass * klass)
           0, G_MAXINT64, DEFAULT_PTIME_MULTIPLE,
           G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
+  /**
+   * GstRTPBasePayload:stats:
+   *
+   * Various payloader statistics retrieved atomically (and are therefore
+   * synchroized with each other), these can be used e.g. to generate an
+   * RTP-Info header. This property return a GstStructure named
+   * application/x-rtp-payload-stats containing the following fields relating to
+   * the last processed buffer and current state of the stream being payloaded:
+   *
+   * <variablelist>
+   *   <varlistentry>
+   *     <term>clock-rate</term>
+   *     <listitem><para>#G_TYPE_UINT, clock-rate of the
+   *     stream</para></listitem>
+   *   </varlistentry>
+   *   <varlistentry>
+   *     <term>seqnum</term>
+   *     <listitem><para>#G_TYPE_UINT, sequence number, same as
+   *     #GstRTPBasePayload:seqnum</para></listitem>
+   *   </varlistentry>
+   *   <varlistentry>
+   *     <term>timestamp</term>
+   *     <listitem><para>#G_TYPE_UINT, RTP timestamp, same as
+   *     #GstRTPBasePayload:timestamp</para></listitem>
+   *   </varlistentry>
+   * </variablelist>
+   **/
+  g_object_class_install_property (G_OBJECT_CLASS (klass), 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_rtp_base_payload_change_state;
 
   klass->get_caps = gst_rtp_base_payload_getcaps_default;
@@ -1051,6 +1083,20 @@ gst_rtp_base_payload_push (GstRTPBasePayload * payload, GstBuffer * buffer)
   return res;
 }
 
+static GstStructure *
+gst_rtp_base_payload_create_stats (GstRTPBasePayload *rtpbasepayload)
+{
+  GstStructure *s;
+
+  s = gst_structure_new ("application/x-rtp-payload-stats",
+    "clock-rate", G_TYPE_UINT, rtpbasepayload->clock_rate,
+    "seqnum", G_TYPE_UINT, rtpbasepayload->seqnum,
+    "timestamp", G_TYPE_UINT, rtpbasepayload->timestamp,
+    NULL);
+
+  return s;
+}
+
 static void
 gst_rtp_base_payload_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
@@ -1158,6 +1204,10 @@ gst_rtp_base_payload_get_property (GObject * object, guint prop_id,
     case PROP_PTIME_MULTIPLE:
       g_value_set_int64 (value, rtpbasepayload->ptime_multiple);
       break;
+    case PROP_STATS:
+      g_value_take_boxed (value,
+          gst_rtp_base_payload_create_stats (rtpbasepayload));
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;

tests/check/libs/rtp-basepayloading.c

@@ -310,6 +310,11 @@ GST_START_TEST (rtp_base_test)
   GMainLoop *mainloop;
   GstBus *bus;
   GstCaps *caps;
+  GstStructure *stats;
+  guint clock_rate;
+  guint seqnum;
+  guint timestamp;
+  GObjectClass *klass;
 
   pipeline = gst_pipeline_new (NULL);
   fail_unless (GST_IS_PIPELINE (pipeline));
@@ -330,6 +335,8 @@ GST_START_TEST (rtp_base_test)
       GST_FORMAT_TIME, NULL);
   gst_caps_unref (caps);
 
+  g_object_set (pay, "seqnum-offset", 0, "timestamp-offset", 0, NULL);
+
   g_object_set (sink, "sync", FALSE, "emit-signals", TRUE, NULL);
 
   gst_bin_add_many (GST_BIN (pipeline), src, pay, depay, sink, NULL);
@@ -357,6 +364,23 @@ GST_START_TEST (rtp_base_test)
   push_buffer (src, 1 * GST_SECOND);
   await_buffer (sink, 1 * GST_SECOND);
 
+  klass = G_OBJECT_GET_CLASS (pay);
+  fail_unless (g_object_class_find_property (klass, "stats") != NULL);
+
+  g_object_get (pay, "stats", &stats, NULL);
+
+  fail_unless (gst_structure_has_field (stats, "clock-rate"));
+  fail_unless (gst_structure_has_field (stats, "seqnum"));
+  fail_unless (gst_structure_has_field (stats, "timestamp"));
+
+  fail_unless (gst_structure_get_uint (stats, "clock-rate", &clock_rate));
+  fail_unless (gst_structure_get_uint (stats, "seqnum", &seqnum));
+  fail_unless (gst_structure_get_uint (stats, "timestamp", &timestamp));
+
+  fail_unless_equals_int (clock_rate, 42);
+  fail_unless_equals_int (seqnum, 1);
+  fail_unless_equals_int (timestamp, 42);
+
   push_eos (src);
   await_eos (sink);