diff --git a/openbsc/src/libmgcp/mgcp_transcode.c b/openbsc/src/libmgcp/mgcp_transcode.c
index 296020c..ff20fb8 100644
--- a/openbsc/src/libmgcp/mgcp_transcode.c
+++ b/openbsc/src/libmgcp/mgcp_transcode.c
@@ -488,7 +488,14 @@
 	nsamples = state->sample_cnt;
 
 	rc = encode_audio(state, dst, buf_size, max_samples);
-	if (rc <= 0)
+	/*
+	 * There were no samples to encode?
+	 * TODO: how does this work for comfort noise?
+	 */
+	if (rc == 0)
+		return -ENOMSG;
+	/* Any other error during the encoding */
+	if (rc < 0)
 		return rc;
 
 	nsamples -= state->sample_cnt;