From 2915d3aba8f52e34a7fd258fbd4182fddfa42879 Mon Sep 17 00:00:00 2001
From: Dragos Oancea <dragos@signalwire.com>
Date: Fri, 7 May 2021 14:17:15 +0000
Subject: [PATCH] [mod_amrwb] add cfg setting mode-set-overwrite (it will
 answer with just one mode-set value) - fixes audio quality issues in
 mod_conference with some UEs.

---
 conf/testing/autoload_configs/amrwb.conf.xml | 2 ++
 conf/vanilla/autoload_configs/amrwb.conf.xml | 2 ++
 src/mod/codecs/mod_amrwb/mod_amrwb.c         | 6 +++++-
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/conf/testing/autoload_configs/amrwb.conf.xml b/conf/testing/autoload_configs/amrwb.conf.xml
index 0bd8e6b733..1163ffd1a6 100644
--- a/conf/testing/autoload_configs/amrwb.conf.xml
+++ b/conf/testing/autoload_configs/amrwb.conf.xml
@@ -18,5 +18,7 @@
 	<param name="adjust-bitrate" value="0"/>
 	<!-- force OA when originating -->
 	<param name="force-oa" value="0"/>
+	<!-- don't mirror mode-set in SDP answer, but use our own (default-bitrate). -->
+	<param name="mode-set-overwrite" value="0"/>
   </settings>
 </configuration>
diff --git a/conf/vanilla/autoload_configs/amrwb.conf.xml b/conf/vanilla/autoload_configs/amrwb.conf.xml
index 0bd8e6b733..1163ffd1a6 100644
--- a/conf/vanilla/autoload_configs/amrwb.conf.xml
+++ b/conf/vanilla/autoload_configs/amrwb.conf.xml
@@ -18,5 +18,7 @@
 	<param name="adjust-bitrate" value="0"/>
 	<!-- force OA when originating -->
 	<param name="force-oa" value="0"/>
+	<!-- don't mirror mode-set in SDP answer, but use our own (default-bitrate). -->
+	<param name="mode-set-overwrite" value="0"/>
   </settings>
 </configuration>
diff --git a/src/mod/codecs/mod_amrwb/mod_amrwb.c b/src/mod/codecs/mod_amrwb/mod_amrwb.c
index ef7891cde6..8be5f4d541 100644
--- a/src/mod/codecs/mod_amrwb/mod_amrwb.c
+++ b/src/mod/codecs/mod_amrwb/mod_amrwb.c
@@ -88,6 +88,7 @@ static struct {
 	switch_byte_t volte;
 	switch_byte_t adjust_bitrate;
 	switch_byte_t force_oa; /*force OA when originating*/
+	switch_byte_t mode_set_overwrite;
 	int debug;
 } globals;
 
@@ -273,7 +274,7 @@ static switch_status_t switch_amrwb_init(switch_codec_t *codec, switch_codec_fla
 			}
 		}
 
-		if (context->enc_modes) {
+		if (context->enc_modes && !globals.mode_set_overwrite) {
 			/* choose the highest mode (bitrate) for high audio quality. */
 			for (i = SWITCH_AMRWB_MODES-2; i > -1; i--) {
 				if (context->enc_modes & (1 << i)) {
@@ -572,6 +573,9 @@ SWITCH_MODULE_LOAD_FUNCTION(mod_amrwb_load)
 				if (!strcasecmp(var, "force-oa")) {
 					globals.force_oa = (switch_byte_t) atoi(val);
 				}
+				if (!strcasecmp(var, "mode-set-overwrite")) {
+					globals.mode_set_overwrite = (switch_byte_t) atoi(val);
+				}
 			}
 		}
 	}