diff --git a/libs/ardour/io.cc b/libs/ardour/io.cc
index 91cbb1cb67..916e77b492 100644
--- a/libs/ardour/io.cc
+++ b/libs/ardour/io.cc
@@ -163,6 +163,8 @@ IO::apply_declick (vector<Sample *>& bufs, uint32_t nbufs, jack_nframes_t nframe
 	double fractional_shift;
 	double fractional_pos;
 	gain_t polscale = invert_polarity ? -1.0f : 1.0f;
+
+	if (nframes == 0) return;
 	
 	fractional_shift = -1.0/declick;
 
diff --git a/libs/ardour/panner.cc b/libs/ardour/panner.cc
index 85feed6be9..6b0013cada 100644
--- a/libs/ardour/panner.cc
+++ b/libs/ardour/panner.cc
@@ -613,7 +613,8 @@ EqualPowerStereoPanner::distribute_automated (Sample* src, Sample** obufs,
 
 	/* store effective pan position. do this even if we are muted */
 
-	effective_x = buffers[0][nframes-1];
+	if (nframes > 0) 
+		effective_x = buffers[0][nframes-1];
 
 	if (_muted) {
 		return;
diff --git a/libs/ardour/route.cc b/libs/ardour/route.cc
index 5d3cd942e7..7f7b56cc2b 100644
--- a/libs/ardour/route.cc
+++ b/libs/ardour/route.cc
@@ -444,7 +444,7 @@ Route::process_output_buffers (vector<Sample*>& bufs, uint32_t nbufs,
 				}
 			}
 			
-			if (apply_gain_automation && _session.transport_rolling()) {
+			if (apply_gain_automation && _session.transport_rolling() && nframes > 0) {
 				_effective_gain = gab[nframes-1];
 			}