diff --git a/src/srtp/srtcp.c b/src/srtp/srtcp.c
index ee4fcc8..23f48f4 100644
--- a/src/srtp/srtcp.c
+++ b/src/srtp/srtcp.c
@@ -49,7 +49,7 @@ int srtcp_encrypt(struct srtp *srtp, struct mbuf *mb)
 
 	strm = stream_get(srtp, ssrc);
 	if (!strm)
-		return ENOMEM;
+		return ENOSR;
 
 	strm->rtcp_index = (strm->rtcp_index+1) & 0x7fffffff;
 
@@ -118,7 +118,7 @@ int srtcp_decrypt(struct srtp *srtp, struct mbuf *mb)
 
 	strm = stream_get(srtp, ssrc);
 	if (!strm)
-		return ENOMEM;
+		return ENOSR;
 
 	pld_start = mb->pos;
 
diff --git a/src/srtp/srtp.c b/src/srtp/srtp.c
index 9382a8c..3cfc1c7 100644
--- a/src/srtp/srtp.c
+++ b/src/srtp/srtp.c
@@ -165,7 +165,7 @@ int srtp_encrypt(struct srtp *srtp, struct mbuf *mb)
 
 	strm = stream_get_seq(srtp, hdr.ssrc, hdr.seq);
 	if (!strm)
-		return ENOMEM;
+		return ENOSR;
 
 	/* Roll-Over Counter (ROC) */
 	if (seq_diff(strm->s_l, hdr.seq) <= -32768) {
@@ -243,7 +243,7 @@ int srtp_decrypt(struct srtp *srtp, struct mbuf *mb)
 
 	strm = stream_get_seq(srtp, hdr.ssrc, hdr.seq);
 	if (!strm)
-		return ENOMEM;
+		return ENOSR;
 
 	diff = seq_diff(strm->s_l, hdr.seq);
 	if (diff > 32768)