diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index 75d39c1..53f1a20 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -237,6 +237,16 @@
 		state->jitter = 0;
 		state->transit = arrival_time - timestamp;
 		state->out_stream = state->in_stream;
+		state->out_stream.last_timestamp = timestamp;
+		/* force output SSRC change */
+		state->out_stream.ssrc = rtp_hdr->ssrc - 1;
+		LOGP(DMGCP, LOGL_INFO,
+			"Initializing stream on 0x%x SSRC: %u timestamp: %u "
+			"from %s:%d in %d\n",
+			ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
+			state->seq_offset,
+			inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
+			endp->conn_mode);
 	} else if (state->in_stream.ssrc != rtp_hdr->ssrc) {
 		int32_t tsdelta = state->out_stream.last_tsdelta;
 		if (tsdelta == 0) {
@@ -286,9 +296,10 @@
 	}
 
 	/* Check again, whether the timestamps are still valid */
-	check_rtp_timestamp(endp, &state->out_stream, rtp_end, addr,
-			    seq, timestamp, "output",
-			    &state->out_stream.last_tsdelta);
+	if (state->out_stream.ssrc == rtp_hdr->ssrc)
+		check_rtp_timestamp(endp, &state->out_stream, rtp_end, addr,
+				    seq, timestamp, "output",
+				    &state->out_stream.last_tsdelta);
 
 	/*
 	 * The below takes the shape of the validation from Appendix A. Check
diff --git a/openbsc/tests/mgcp/mgcp_test.ok b/openbsc/tests/mgcp/mgcp_test.ok
index 57d3bfb..4d3caac 100644
--- a/openbsc/tests/mgcp/mgcp_test.ok
+++ b/openbsc/tests/mgcp/mgcp_test.ok
@@ -80,15 +80,15 @@
 TS: 1560, dTS: 160, TS Errs: in 5, out 5
 TS: 1720, dTS: 160, TS Errs: in 5, out 5
 Output SSRC changed to 10203040
-TS: 34688, dTS: 32968, TS Errs: in 5, out 6
-TS: 34848, dTS: 160, TS Errs: in 5, out 7
-TS: 35008, dTS: 160, TS Errs: in 5, out 7
-TS: 35128, dTS: 120, TS Errs: in 6, out 8
-TS: 35288, dTS: 160, TS Errs: in 7, out 9
-TS: 35448, dTS: 160, TS Errs: in 7, out 9
-TS: 35768, dTS: 160, TS Errs: in 7, out 9
-TS: 35928, dTS: 160, TS Errs: in 7, out 9
-TS: 36088, dTS: 160, TS Errs: in 8, out 10
+TS: 34688, dTS: 160, TS Errs: in 5, out 5
+TS: 34848, dTS: 160, TS Errs: in 5, out 5
+TS: 35008, dTS: 160, TS Errs: in 5, out 5
+TS: 35128, dTS: 120, TS Errs: in 6, out 6
+TS: 35288, dTS: 160, TS Errs: in 7, out 7
+TS: 35448, dTS: 160, TS Errs: in 7, out 7
+TS: 35768, dTS: 160, TS Errs: in 7, out 7
+TS: 35928, dTS: 160, TS Errs: in 7, out 7
+TS: 36088, dTS: 160, TS Errs: in 8, out 8
 Testing packet error detection, patch timestamps.
 Output SSRC changed to 11223344
 TS: 0, dTS: 0, TS Errs: in 0, out 0
@@ -104,15 +104,15 @@
 TS: 1560, dTS: 160, TS Errs: in 5, out 5
 TS: 1720, dTS: 160, TS Errs: in 5, out 5
 Output SSRC changed to 10203040
-TS: 34688, dTS: 32968, TS Errs: in 5, out 6
-TS: 34848, dTS: 160, TS Errs: in 5, out 7
-TS: 35008, dTS: 160, TS Errs: in 5, out 7
-TS: 35128, dTS: 120, TS Errs: in 6, out 8
-TS: 35288, dTS: 160, TS Errs: in 7, out 9
-TS: 35448, dTS: 160, TS Errs: in 7, out 9
-TS: 35768, dTS: 160, TS Errs: in 7, out 9
-TS: 35928, dTS: 160, TS Errs: in 7, out 9
-TS: 36088, dTS: 160, TS Errs: in 8, out 10
+TS: 34688, dTS: 160, TS Errs: in 5, out 5
+TS: 34848, dTS: 160, TS Errs: in 5, out 5
+TS: 35008, dTS: 160, TS Errs: in 5, out 5
+TS: 35128, dTS: 120, TS Errs: in 6, out 6
+TS: 35288, dTS: 160, TS Errs: in 7, out 7
+TS: 35448, dTS: 160, TS Errs: in 7, out 7
+TS: 35768, dTS: 160, TS Errs: in 7, out 7
+TS: 35928, dTS: 160, TS Errs: in 7, out 7
+TS: 36088, dTS: 160, TS Errs: in 8, out 8
 Testing packet error detection, patch SSRC, patch timestamps.
 Output SSRC changed to 11223344
 TS: 0, dTS: 0, TS Errs: in 0, out 0