diff --git a/openbsc/src/libmgcp/mgcp_transcode.c b/openbsc/src/libmgcp/mgcp_transcode.c
index ed5f50b..8ab9a04 100644
--- a/openbsc/src/libmgcp/mgcp_transcode.c
+++ b/openbsc/src/libmgcp/mgcp_transcode.c
@@ -500,5 +500,10 @@
 	state->next_seq += 1;
 	state->next_time = ts_no + nsamples;
 
+	/*
+	 * XXX: At this point we should always have consumed
+	 * samples. So doing OSMO_ASSERT(nsamples > 0) and returning
+	 * rtp_hdr_size should be fine.
+	 */
 	return nsamples ? rtp_hdr_size : 0;
 }