gstrtpsession: suggest upstream to use the new "internal-ssrc" after a collision

When a collision is found on the internal ssrc, we have to change it.
Ideally, we want also the payloader upstream to follow this change and use
the new internal ssrc. Ideally we want this condition to be always met:
if there is one payloader sending on this session, its ssrc should match the
internal ssrc.

diff --git a/gst/rtpmanager/gstrtpsession.c b/gst/rtpmanager/gstrtpsession.c
index f51b613..80ac1c1 100644 (file)
--- a/gst/rtpmanager/gstrtpsession.c
+++ b/gst/rtpmanager/gstrtpsession.c
@@ -333,9 +333,25 @@ on_ssrc_collision (RTPSession * session, RTPSource * src, GstRtpSession * sess)
   GST_RTP_SESSION_UNLOCK (sess);
 
   if (send_rtp_sink) {
-    GstEvent *event = gst_event_new_custom (GST_EVENT_CUSTOM_UPSTREAM,
-        gst_structure_new ("GstRTPCollision", "ssrc", G_TYPE_UINT,
-            (guint) src->ssrc, NULL));
+    GstStructure *structure;
+    GstEvent *event;
+    RTPSource *internal_src;
+    guint32 suggested_ssrc;
+
+    structure = gst_structure_new ("GstRTPCollision", "ssrc", G_TYPE_UINT,
+        (guint) src->ssrc, NULL);
+
+    /* if there is no source using the suggested ssrc, most probably because
+     * this ssrc has just collided, suggest upstream to use it */
+    suggested_ssrc = rtp_session_suggest_ssrc (session);
+    internal_src = rtp_session_get_source_by_ssrc (session, suggested_ssrc);
+    if (!internal_src)
+      gst_structure_set (structure, "suggested-ssrc", G_TYPE_UINT,
+          (guint) suggested_ssrc, NULL);
+    else
+      g_object_unref (internal_src);
+
+    event = gst_event_new_custom (GST_EVENT_CUSTOM_UPSTREAM, structure);
     gst_pad_push_event (send_rtp_sink, event);
     gst_object_unref (send_rtp_sink);
   }