From c726add352e8099591576bf8caa0b35e1ddc2075 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Tue, 13 Feb 2024 17:43:15 +0200
Subject: [PATCH] rtpfunnel: Handle NTP-64 RTP header extension in caps similar
 to TWCC

This is another header extension that is handled by rtpsession and needs
to be preserved in the caps that are created by rtpfunnel.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6109>
---
 .../gst/rtpmanager/gstrtpfunnel.c             | 34 ++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/subprojects/gst-plugins-good/gst/rtpmanager/gstrtpfunnel.c b/subprojects/gst-plugins-good/gst/rtpmanager/gstrtpfunnel.c
index 667f80fed6..d403015e14 100644
--- a/subprojects/gst-plugins-good/gst/rtpmanager/gstrtpfunnel.c
+++ b/subprojects/gst-plugins-good/gst/rtpmanager/gstrtpfunnel.c
@@ -132,6 +132,8 @@ struct _GstRtpFunnel
   guint twcc_pads;              /* numer of sinkpads with negotiated twcc */
   GstRTPHeaderExtension *twcc_ext;
 
+  guint8 current_ntp64_ext_id;
+
   /* properties */
   gint common_ts_offset;
 };
@@ -324,6 +326,9 @@ gst_rtp_funnel_sink_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
       GST_MINI_OBJECT_CAST (buffer));
 }
 
+#define TWCC_EXTMAP_STR "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01"
+#define NTP64_EXTMAP_STR "urn:ietf:params:rtp-hdrext:ntp-64"
+
 static void
 gst_rtp_funnel_set_twcc_ext_id (GstRtpFunnel * funnel, guint8 twcc_ext_id)
 {
@@ -336,6 +341,7 @@ gst_rtp_funnel_set_twcc_ext_id (GstRtpFunnel * funnel, guint8 twcc_ext_id)
   if (current_ext_id == twcc_ext_id)
     return;
 
+  GST_DEBUG_OBJECT (funnel, "Got TWCC RTP header extension id %u", twcc_ext_id);
   name = g_strdup_printf ("extmap-%u", twcc_ext_id);
 
   gst_caps_set_simple (funnel->srccaps, name, G_TYPE_STRING,
@@ -349,7 +355,28 @@ gst_rtp_funnel_set_twcc_ext_id (GstRtpFunnel * funnel, guint8 twcc_ext_id)
   gst_rtp_header_extension_set_id (funnel->twcc_ext, twcc_ext_id);
 }
 
-#define TWCC_EXTMAP_STR "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01"
+static void
+gst_rtp_funnel_set_ntp64_ext_id (GstRtpFunnel * funnel, guint8 ntp64_ext_id)
+{
+  gchar *name;
+
+  if (funnel->current_ntp64_ext_id == ntp64_ext_id)
+    return;
+
+  GST_DEBUG_OBJECT (funnel, "Got NTP-64 RTP header extension id %u",
+      ntp64_ext_id);
+  funnel->current_ntp64_ext_id = ntp64_ext_id;
+
+  name = g_strdup_printf ("extmap-%u", ntp64_ext_id);
+
+  gst_caps_set_simple (funnel->srccaps, name, G_TYPE_STRING,
+      NTP64_EXTMAP_STR, NULL);
+
+  g_free (name);
+
+  /* make sure we update the sticky with the new caps */
+  funnel->send_sticky_events = TRUE;
+}
 
 static gboolean
 gst_rtp_funnel_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
@@ -403,6 +430,11 @@ gst_rtp_funnel_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
         funnel->twcc_pads++;
         gst_rtp_funnel_set_twcc_ext_id (funnel, ext_id);
       }
+
+      ext_id = gst_rtp_get_extmap_id_for_attribute (s, NTP64_EXTMAP_STR);
+      if (ext_id > 0) {
+        gst_rtp_funnel_set_ntp64_ext_id (funnel, ext_id);
+      }
       GST_OBJECT_UNLOCK (funnel);
 
       forward = FALSE;