diff --git a/daemon/main.c b/daemon/main.c
index eb1de4afb..5ef488fa8 100644
--- a/daemon/main.c
+++ b/daemon/main.c
@@ -1036,6 +1036,10 @@ static void options(int *argc, char ***argv) {
 			rtpe_config.mos = MOS_CQ;
 		else if (!strcasecmp(mos, "lq"))
 			rtpe_config.mos = MOS_LQ;
+#ifdef WITH_TRANSCODING
+		else if (!strcasecmp(mos, "legacy"))
+			rtpe_config.common.mos_type = MOS_LEGACY;
+#endif
 		else
 			die("Invalid --mos option ('%s')", mos);
 	}
diff --git a/daemon/ssrc.c b/daemon/ssrc.c
index 1089adda7..bd7234460 100644
--- a/daemon/ssrc.c
+++ b/daemon/ssrc.c
@@ -8,6 +8,15 @@
 #include "codeclib.h"
 #include "bufferpool.h"
 
+typedef void mos_calc_fn(struct ssrc_stats_block *ssb);
+static mos_calc_fn mos_calc_legacy;
+
+#ifdef WITH_TRANSCODING
+static mos_calc_fn *mos_calcs[__MOS_TYPES] = {
+	[MOS_LEGACY] = mos_calc_legacy,
+};
+#endif
+
 static void __free_ssrc_entry_call(void *e);
 
 
@@ -67,7 +76,7 @@ static void ssrc_entry_put(void *ep) {
 }
 
 // returned as mos * 10 (i.e. 10 - 50 for 1.0 to 5.0)
-static void mos_calc(struct ssrc_stats_block *ssb) {
+static void mos_calc_legacy(struct ssrc_stats_block *ssb) {
 	uint64_t rtt = ssb->rtt;
 	if (rtpe_config.mos == MOS_CQ && !rtt)
 		return; // can not compute the MOS-CQ unless we have a valid RTT
@@ -422,6 +431,12 @@ void ssrc_receiver_report(struct call_media *m, stream_fd *sfd, const struct ssr
 	RTPE_SAMPLE_SFD(rtt_dsct, rtt, sfd);
 	RTPE_SAMPLE_SFD(packetloss, ssb->packetloss, sfd);
 
+	mos_calc_fn *mos_calc = mos_calc_legacy;
+#ifdef WITH_TRANSCODING
+	if (rpt->codec_def)
+		mos_calc = mos_calcs[rpt->codec_def->mos_type];
+#endif
+
 	other_e->packets_lost = rr->packets_lost;
 	mos_calc(ssb);
 	if (ssb->mos) {
diff --git a/lib/auxlib.h b/lib/auxlib.h
index 3d08bd4df..98555dab8 100644
--- a/lib/auxlib.h
+++ b/lib/auxlib.h
@@ -37,6 +37,7 @@ struct rtpengine_common_config {
 	gboolean io_uring;
 	int io_uring_buffers;
 	int max_log_line_length;
+	int mos_type;				// enum in codec_def_t
 	char *evs_lib_path;
 	char *codec_chain_lib_path;
 	int codec_chain_runners;
diff --git a/lib/codeclib.c b/lib/codeclib.c
index 502868150..666545ca8 100644
--- a/lib/codeclib.c
+++ b/lib/codeclib.c
@@ -1652,6 +1652,9 @@ void codeclib_init(int print) {
 
 		if (def->supplemental)
 			g_queue_push_tail(&__supplemental_codecs, def);
+
+		if (rtpe_common_config_ptr->mos_type)
+			def->mos_type = rtpe_common_config_ptr->mos_type;
 	}
 }
 
diff --git a/lib/codeclib.h b/lib/codeclib.h
index dfb37df69..3b2b21054 100644
--- a/lib/codeclib.h
+++ b/lib/codeclib.h
@@ -198,6 +198,11 @@ struct codec_def_s {
 	const int bits_per_sample;
 	const enum media_type media_type;
 	const str silence_pattern;
+	enum {
+		MOS_LEGACY = 0, // default
+
+		__MOS_TYPES
+	} mos_type;
 
 	// codec-specific callbacks
 	format_init_f *init;