diff --git a/src/libmsc/codec_mapping.c b/src/libmsc/codec_mapping.c
index 55efd8de4..c2afc9cee 100644
--- a/src/libmsc/codec_mapping.c
+++ b/src/libmsc/codec_mapping.c
@@ -24,6 +24,9 @@
 
 #include <osmocom/gsm/mncc.h>
 
+#include <osmocom/sdp/fmtp.h>
+#include <osmocom/sdp/sdp_strings.h>
+
 #include <osmocom/msc/sdp_msg.h>
 #include <osmocom/msc/codec_mapping.h>
 #include <osmocom/msc/mncc.h>
@@ -118,7 +121,7 @@ const struct codec_mapping codec_map[] = {
 			/* AMR is always octet-aligned in 2G and 3G RAN, so this fmtp is signalled to remote call legs.
 			 * So far, fmtp is ignored in incoming SIP SDP, so an incoming SDP without 'octet-align=1' will
 			 * match with this entry; we will still reply with 'octet-align=1', which often works out. */
-			.fmtp = "octet-align=1",
+			.fmtp = OSMO_SDP_VAL_AMR_OCTET_ALIGN_1,
 		},
 		.mgcp = CODEC_AMR_8000_1,
 		.speech_ver_count = 1,
@@ -139,7 +142,7 @@ const struct codec_mapping codec_map[] = {
 			.payload_type = 112,
 			.subtype_name = "AMR",
 			.rate = 8000,
-			.fmtp = "octet-align=1",
+			.fmtp = OSMO_SDP_VAL_AMR_OCTET_ALIGN_1,
 		},
 		.mgcp = CODEC_AMR_8000_1,
 		.speech_ver_count = 1,
@@ -159,7 +162,7 @@ const struct codec_mapping codec_map[] = {
 			.payload_type = 113,
 			.subtype_name = "AMR-WB",
 			.rate = 16000,
-			.fmtp = "octet-align=1",
+			.fmtp = OSMO_SDP_STR_AMR_OCTET_ALIGN_1,
 		},
 		.mgcp = CODEC_AMRWB_16000_1,
 		.speech_ver_count = 2,
diff --git a/src/libmsc/sdp_msg.c b/src/libmsc/sdp_msg.c
index 9b4cd988c..a70752e0b 100644
--- a/src/libmsc/sdp_msg.c
+++ b/src/libmsc/sdp_msg.c
@@ -27,6 +27,8 @@
 #include <osmocom/core/utils.h>
 #include <osmocom/core/logging.h>
 
+#include <osmocom/mgcp_client/fmtp.h>
+
 #include <osmocom/msc/debug.h>
 #include <osmocom/msc/sdp_msg.h>
 
@@ -272,7 +274,7 @@ int sdp_msg_to_sdp_str_buf(char *dst, size_t dst_size, const struct sdp_msg *sdp
 		OSMO_STRBUF_PRINTF(sb, "a=rtpmap:%d %s/%d\r\n", codec->payload_type, codec->subtype_name,
 				   codec->rate > 0 ? codec->rate : 8000);
 		if (codec->fmtp[0])
-			OSMO_STRBUF_PRINTF(sb, "a=fmtp:%d %s\r\n", codec->payload_type, codec->fmtp);
+			OSMO_STRBUF_PRINTF(sb, OSMO_SDP_PREFIX_A_FMTP "%d %s\r\n", codec->payload_type, codec->fmtp);
 	}
 
 	OSMO_STRBUF_PRINTF(sb, "a=ptime:%d\r\n", sdp->ptime > 0? sdp->ptime : 20);
@@ -302,7 +304,6 @@ int sdp_parse_attrib(struct sdp_msg *sdp, const char *src)
 	unsigned int payload_type;
 	struct sdp_audio_codec *codec;
 #define A_RTPMAP "rtpmap:"
-#define A_FMTP "fmtp:"
 #define A_PTIME "ptime:"
 #define A_RTCP "rtcp:"
 
@@ -328,11 +329,11 @@ int sdp_parse_attrib(struct sdp_msg *sdp, const char *src)
 			return -ENOTSUP;
 	}
 
-	else if (osmo_str_startswith(src, A_FMTP)) {
+	else if (osmo_str_startswith(src, OSMO_SDP_PREFIX_FMTP)) {
 		/* "a=fmtp:112 octet-align=1;mode-set=0,1,2,3" */
 		char *fmtp_str;
 		const char *line_end = sdp_msg_line_end(src);
-		if (sscanf(src, A_FMTP "%u", &payload_type) != 1)
+		if (sscanf(src, OSMO_SDP_PREFIX_FMTP "%u", &payload_type) != 1)
 			return -EINVAL;
 
 		fmtp_str = strchr(src, ' ');