From 4b1c49d70ccf6d2fd2ee7d6785e3b9ebcc42d3cc Mon Sep 17 00:00:00 2001
From: Lorenzo Miniero <lminiero@gmail.com>
Date: Fri, 28 Feb 2020 18:18:24 +0100
Subject: [PATCH] Remove duplicated codecs when answering SIP call (#1966)

---
 plugins/janus_sip.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/plugins/janus_sip.c b/plugins/janus_sip.c
index 880fd519e2..455a2ed667 100644
--- a/plugins/janus_sip.c
+++ b/plugins/janus_sip.c
@@ -5512,6 +5512,8 @@ void janus_sip_sdp_process(janus_sip_session *session, janus_sdp *sdp, gboolean
 char *janus_sip_sdp_manipulate(janus_sip_session *session, janus_sdp *sdp, gboolean answer) {
 	if(!session || !session->stack || !sdp)
 		return NULL;
+	GHashTable *codecs = NULL;
+	GList *pts_to_remove = NULL;
 	/* Start replacing stuff */
 	JANUS_LOG(LOG_VERB, "Setting protocol to %s\n", session->media.require_srtp ? "RTP/SAVP" : "RTP/AVP");
 	if(sdp->c_addr) {
@@ -5561,8 +5563,45 @@ char *janus_sip_sdp_manipulate(janus_sip_session *session, janus_sdp *sdp, gbool
 				}
 			}
 		}
+		/* If this is an answer, get rid of multiple versions of the same
+		 * codec as well (e.g., video profiles), as that confuses the hell
+		 * out of SOATAG_RTP_SELECT(SOA_RTP_SELECT_COMMON) in nua_respond() */
+		if(answer) {
+			if(codecs == NULL)
+				codecs = g_hash_table_new_full(g_str_hash, g_str_equal, (GDestroyNotify)g_free, NULL);
+			/* Check all rtpmap attributes */
+			int pt = -1;
+			char codec[50];
+			GList *ma = m->attributes;
+			while(ma) {
+				janus_sdp_attribute *a = (janus_sdp_attribute *)ma->data;
+				if(a->name != NULL && a->value != NULL && !strcasecmp(a->name, "rtpmap")) {
+					if(sscanf(a->value, "%3d %s", &pt, codec) == 2) {
+						if(g_hash_table_lookup(codecs, codec) != NULL) {
+							/* We already have a version of this codec, remove the payload type */
+							pts_to_remove = g_list_append(pts_to_remove, GINT_TO_POINTER(pt));
+							JANUS_LOG(LOG_HUGE, "Removing %d (%s)\n", pt, codec);
+						} else {
+							/* Keep track of this codec */
+							g_hash_table_insert(codecs, g_strdup(codec), GINT_TO_POINTER(pt));
+						}
+					}
+				}
+				ma = ma->next;
+			}
+		}
 		temp = temp->next;
 	}
+	/* If we need to remove some payload types from the SDP, do it now */
+	if(pts_to_remove != NULL) {
+		GList *temp = pts_to_remove;
+		while(temp) {
+			int pt = GPOINTER_TO_INT(temp->data);
+			janus_sdp_remove_payload_type(sdp, pt);
+			temp = temp->next;
+		}
+		g_list_free(pts_to_remove);
+	}
 	/* Generate a SDP string out of our changes */
 	return janus_sdp_write(sdp);
 }