diff --git a/src/srtp/srtcp.c b/src/srtp/srtcp.c
index 23f48f4..94155e0 100644
--- a/src/srtp/srtcp.c
+++ b/src/srtp/srtcp.c
@@ -47,9 +47,9 @@ int srtcp_encrypt(struct srtp *srtp, struct mbuf *mb)
 	if (err)
 		return err;
 
-	strm = stream_get(srtp, ssrc);
-	if (!strm)
-		return ENOSR;
+	err = stream_get(&strm, srtp, ssrc);
+	if (err)
+		return err;
 
 	strm->rtcp_index = (strm->rtcp_index+1) & 0x7fffffff;
 
@@ -116,9 +116,9 @@ int srtcp_decrypt(struct srtp *srtp, struct mbuf *mb)
 	if (err)
 		return err;
 
-	strm = stream_get(srtp, ssrc);
-	if (!strm)
-		return ENOSR;
+	err = stream_get(&strm, srtp, ssrc);
+	if (err)
+		return err;
 
 	pld_start = mb->pos;
 
diff --git a/src/srtp/srtp.c b/src/srtp/srtp.c
index 3cfc1c7..1e99e0e 100644
--- a/src/srtp/srtp.c
+++ b/src/srtp/srtp.c
@@ -163,9 +163,9 @@ int srtp_encrypt(struct srtp *srtp, struct mbuf *mb)
 	if (err)
 		return err;
 
-	strm = stream_get_seq(srtp, hdr.ssrc, hdr.seq);
-	if (!strm)
-		return ENOSR;
+	err = stream_get_seq(&strm, srtp, hdr.ssrc, hdr.seq);
+	if (err)
+		return err;
 
 	/* Roll-Over Counter (ROC) */
 	if (seq_diff(strm->s_l, hdr.seq) <= -32768) {
@@ -241,9 +241,9 @@ int srtp_decrypt(struct srtp *srtp, struct mbuf *mb)
 	if (err)
 		return err;
 
-	strm = stream_get_seq(srtp, hdr.ssrc, hdr.seq);
-	if (!strm)
-		return ENOSR;
+	err = stream_get_seq(&strm, srtp, hdr.ssrc, hdr.seq);
+	if (err)
+		return err;
 
 	diff = seq_diff(strm->s_l, hdr.seq);
 	if (diff > 32768)
diff --git a/src/srtp/srtp.h b/src/srtp/srtp.h
index 9cb94a3..a937337 100644
--- a/src/srtp/srtp.h
+++ b/src/srtp/srtp.h
@@ -49,9 +49,9 @@ struct srtp {
 };
 
 
-struct srtp_stream *stream_get(struct srtp *srtp, uint32_t ssrc);
-struct srtp_stream *stream_get_seq(struct srtp *srtp, uint32_t ssrc,
-				   uint16_t seq);
+int stream_get(struct srtp_stream **strmp, struct srtp *srtp, uint32_t ssrc);
+int stream_get_seq(struct srtp_stream **strmp, struct srtp *srtp,
+		   uint32_t ssrc, uint16_t seq);
 
 
 int  srtp_derive(uint8_t *out, size_t out_len, uint8_t label,
diff --git a/src/srtp/stream.c b/src/srtp/stream.c
index 78524cf..abc6c48 100644
--- a/src/srtp/stream.c
+++ b/src/srtp/stream.c
@@ -12,9 +12,9 @@
 
 
 /** SRTP protocol values */
-enum {
-	MAX_STREAMS  = 8,  /**< Maximum number of SRTP streams */
-};
+#ifndef SRTP_MAX_STREAMS
+#define SRTP_MAX_STREAMS  (8)  /**< Maximum number of SRTP streams */
+#endif
 
 
 static void stream_destructor(void *arg)
@@ -41,16 +41,17 @@ static struct srtp_stream *stream_find(struct srtp *srtp, uint32_t ssrc)
 }
 
 
-static struct srtp_stream *stream_new(struct srtp *srtp, uint32_t ssrc)
+static int stream_new(struct srtp_stream **strmp, struct srtp *srtp,
+		      uint32_t ssrc)
 {
 	struct srtp_stream *strm;
 
-	if (list_count(&srtp->streaml) >= MAX_STREAMS)
-		return NULL;
+	if (list_count(&srtp->streaml) >= SRTP_MAX_STREAMS)
+		return ENOSR;
 
 	strm = mem_zalloc(sizeof(*strm), stream_destructor);
 	if (!strm)
-		return NULL;
+		return ENOMEM;
 
 	strm->ssrc = ssrc;
 	srtp_replay_init(&strm->replay_rtp);
@@ -58,33 +59,42 @@ static struct srtp_stream *stream_new(struct srtp *srtp, uint32_t ssrc)
 
 	list_append(&srtp->streaml, &strm->le, strm);
 
-	return strm;
+	if (strmp)
+		*strmp = strm;
+
+	return 0;
 }
 
 
-struct srtp_stream *stream_get(struct srtp *srtp, uint32_t ssrc)
+int stream_get(struct srtp_stream **strmp, struct srtp *srtp, uint32_t ssrc)
 {
 	struct srtp_stream *strm;
 
-	if (!srtp)
-		return NULL;
+	if (!strmp || !srtp)
+		return EINVAL;
 
 	strm = stream_find(srtp, ssrc);
-	if (strm)
-		return strm;
+	if (strm) {
+		*strmp = strm;
+		return 0;
+	}
 
-	return stream_new(srtp, ssrc);
+	return stream_new(strmp, srtp, ssrc);
 }
 
 
-struct srtp_stream *stream_get_seq(struct srtp *srtp, uint32_t ssrc,
-				   uint16_t seq)
+int stream_get_seq(struct srtp_stream **strmp, struct srtp *srtp,
+		   uint32_t ssrc, uint16_t seq)
 {
 	struct srtp_stream *strm;
+	int err;
 
-	strm = stream_get(srtp, ssrc);
-	if (!strm)
-		return NULL;
+	if (!strmp || !srtp)
+		return EINVAL;
+
+	err = stream_get(&strm, srtp, ssrc);
+	if (err)
+		return err;
 
 	/* Set the initial sequence number once only */
 	if (!strm->s_l_set) {
@@ -92,5 +102,7 @@ struct srtp_stream *stream_get_seq(struct srtp *srtp, uint32_t ssrc,
 		strm->s_l_set = true;
 	}
 
-	return strm;
+	*strmp = strm;
+
+	return 0;
 }