From 72b6dabd3263f0a7ebe294a106cce18ab525f8c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Mon, 3 Oct 2022 19:12:55 +0300
Subject: [PATCH] rtpsession: Remember the corresponding media SSRC for RTX
 sources

This allows timing out the RTX source and sending BYE for it when the
actual media source belonging to it is timed out.

This change only applies to sending sources from this session.

Fixes https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/issues/360

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3112>
---
 .../gst/rtpmanager/rtpsession.c               |  3 ++-
 .../gst/rtpmanager/rtpsource.c                | 19 ++++++++++++++++++-
 .../gst/rtpmanager/rtpsource.h                |  3 +++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/subprojects/gst-plugins-good/gst/rtpmanager/rtpsession.c b/subprojects/gst-plugins-good/gst/rtpmanager/rtpsession.c
index c9581b08d4..48ef879b3b 100644
--- a/subprojects/gst-plugins-good/gst/rtpmanager/rtpsession.c
+++ b/subprojects/gst-plugins-good/gst/rtpmanager/rtpsession.c
@@ -4167,7 +4167,8 @@ session_cleanup (const gchar * key, RTPSource * source, ReportData * data)
         /* this is an internal source that is not using our suggested ssrc.
          * since there must be another source using this ssrc, we can remove
          * this one instead of making it a receiver forever */
-        if (source->ssrc != sess->suggested_ssrc) {
+        if (source->ssrc != sess->suggested_ssrc
+            && source->media_ssrc != sess->suggested_ssrc) {
           rtp_source_mark_bye (source, "timed out");
           /* do not schedule bye here, since we are inside the RTCP timeout
            * processing and scheduling bye will interfere with SR/RR sending */
diff --git a/subprojects/gst-plugins-good/gst/rtpmanager/rtpsource.c b/subprojects/gst-plugins-good/gst/rtpmanager/rtpsource.c
index cb12644039..0a0d858c4b 100644
--- a/subprojects/gst-plugins-good/gst/rtpmanager/rtpsource.c
+++ b/subprojects/gst-plugins-good/gst/rtpmanager/rtpsource.c
@@ -825,6 +825,7 @@ rtp_source_update_send_caps (RTPSource * src, GstCaps * caps)
   GstStructure *s;
   guint val;
   gint ival;
+  guint ssrc, rtx_ssrc = -1;
   gboolean rtx;
 
   /* nothing changed, return */
@@ -833,7 +834,17 @@ rtp_source_update_send_caps (RTPSource * src, GstCaps * caps)
 
   s = gst_caps_get_structure (caps, 0);
 
-  rtx = (gst_structure_get_uint (s, "rtx-ssrc", &val) && val == src->ssrc);
+  if (!gst_structure_get_uint (s, "ssrc", &ssrc))
+    return;
+  gst_structure_get_uint (s, "rtx-ssrc", &rtx_ssrc);
+
+  if (src->ssrc != ssrc && src->ssrc != rtx_ssrc) {
+    GST_WARNING ("got ssrc %u/%u that doesn't match with this source's ssrc %u",
+        ssrc, rtx_ssrc, src->ssrc);
+    return;
+  }
+
+  rtx = (rtx_ssrc == src->ssrc);
 
   if (gst_structure_get_int (s, rtx ? "rtx-payload" : "payload", &ival))
     src->payload = ival;
@@ -859,6 +870,12 @@ rtp_source_update_send_caps (RTPSource * src, GstCaps * caps)
       src->seqnum_offset);
 
   gst_caps_replace (&src->send_caps, caps);
+
+  if (rtx) {
+    src->media_ssrc = ssrc;
+  } else {
+    src->media_ssrc = -1;
+  }
 }
 
 /**
diff --git a/subprojects/gst-plugins-good/gst/rtpmanager/rtpsource.h b/subprojects/gst-plugins-good/gst/rtpmanager/rtpsource.h
index a2723050ee..e23d53700d 100644
--- a/subprojects/gst-plugins-good/gst/rtpmanager/rtpsource.h
+++ b/subprojects/gst-plugins-good/gst/rtpmanager/rtpsource.h
@@ -137,6 +137,9 @@ struct _RTPSource {
   /*< private >*/
   guint32       ssrc;
 
+  /* If not -1 then this is the SSRC of the corresponding media RTPSource */
+  guint32       media_ssrc;
+
   guint16       generation;
   GHashTable    *reported_in_sr_of;     /* set of SSRCs */