diff --git a/pjmedia/src/pjmedia-codec/gsm.c b/pjmedia/src/pjmedia-codec/gsm.c
index 5dc2034..7bb4d72 100644
--- a/pjmedia/src/pjmedia-codec/gsm.c
+++ b/pjmedia/src/pjmedia-codec/gsm.c
@@ -597,7 +597,7 @@
 
 #if !PLC_DISABLED
     if (gsm_data->plc_enabled)
-	pjmedia_plc_save( gsm_data->plc, output->buf);
+	pjmedia_plc_save( gsm_data->plc, (pj_int16_t*)output->buf);
 #endif
 
     return PJ_SUCCESS;
@@ -612,13 +612,13 @@
 				      unsigned output_buf_len,
 				      struct pjmedia_frame *output)
 {
-    struct gsm_data *gsm_data = codec->codec_data;
+    struct gsm_data *gsm_data = (struct gsm_data*) codec->codec_data;
 
     PJ_ASSERT_RETURN(gsm_data->plc_enabled, PJ_EINVALIDOP);
 
     PJ_ASSERT_RETURN(output_buf_len >= 320, PJMEDIA_CODEC_EPCMTOOSHORT);
 
-    pjmedia_plc_generate(gsm_data->plc, output->buf);
+    pjmedia_plc_generate(gsm_data->plc, (pj_int16_t*)output->buf);
     output->size = 320;
 
     return PJ_SUCCESS;
diff --git a/pjmedia/src/pjmedia/resample_port.c b/pjmedia/src/pjmedia/resample_port.c
index 44f7e39..e28d3c8 100644
--- a/pjmedia/src/pjmedia/resample_port.c
+++ b/pjmedia/src/pjmedia/resample_port.c
@@ -188,8 +188,11 @@
 	/* Copy whatever returned as long as the buffer size is enough */
 	frame->size = tmp_frame.size < rport->base.info.bytes_per_frame ?
 		      tmp_frame.size : rport->base.info.bytes_per_frame;
-	if (tmp_frame.size)
-	    pjmedia_copy_samples(frame->buf, tmp_frame.buf, frame->size >> 1);
+	if (tmp_frame.size) {
+	    pjmedia_copy_samples((pj_int16_t*)frame->buf, 
+				 (const pj_int16_t*)tmp_frame.buf, 
+				 frame->size >> 1);
+	}
 	return PJ_SUCCESS;
     }
 
diff --git a/pjmedia/src/pjmedia/transport_srtp.c b/pjmedia/src/pjmedia/transport_srtp.c
index 0ebe075..6f3c06f 100644
--- a/pjmedia/src/pjmedia/transport_srtp.c
+++ b/pjmedia/src/pjmedia/transport_srtp.c
@@ -1186,7 +1186,7 @@
     struct transport_srtp *srtp = (struct transport_srtp*) tp;
     pjmedia_sdp_media *m_rem, *m_loc;
     pj_status_t status;
-    int i;
+    unsigned i;
 
     PJ_ASSERT_RETURN(tp && pool && sdp_local && sdp_remote, PJ_EINVAL);