diff --git a/src/examples/audio-dsp-filter.c b/src/examples/audio-dsp-filter.c
index 9f1992b48..fbcc22671 100644
--- a/src/examples/audio-dsp-filter.c
+++ b/src/examples/audio-dsp-filter.c
@@ -79,6 +79,9 @@ static void on_process(void *userdata, struct spa_io_position *position)
 	in = pw_filter_get_dsp_buffer(data->in_port, n_samples);
 	out = pw_filter_get_dsp_buffer(data->out_port, n_samples);
 
+	if (in == NULL || out == NULL)
+		return;
+
 	memcpy(out, in, n_samples * sizeof(float));
 }
 
diff --git a/src/examples/audio-dsp-src.c b/src/examples/audio-dsp-src.c
index beaecfe72..d7bf52382 100644
--- a/src/examples/audio-dsp-src.c
+++ b/src/examples/audio-dsp-src.c
@@ -77,6 +77,8 @@ static void on_process(void *userdata, struct spa_io_position *position)
 	pw_log_trace("do process %d", n_samples);
 
 	out = pw_filter_get_dsp_buffer(out_port, n_samples);
+	if (out == NULL)
+		return;
 
 	for (i = 0; i < n_samples; i++) {
 		out_port->accumulator += M_PI_M2 * DEFAULT_FREQ / DEFAULT_RATE;