diff --git a/gtk2_ardour/audio_region_editor.cc b/gtk2_ardour/audio_region_editor.cc
index 1823ab1303..2fb5ac5697 100644
--- a/gtk2_ardour/audio_region_editor.cc
+++ b/gtk2_ardour/audio_region_editor.cc
@@ -17,8 +17,11 @@
 
 */
 
+#include <boost/lexical_cast.hpp>
+
 #include "pbd/memento_command.h"
 #include "pbd/stateful_diff_command.h"
+#include "pbd/pthread_utils.h"
 
 #include "ardour/session.h"
 #include "ardour/audioregion.h"
@@ -41,28 +44,63 @@ using namespace PBD;
 using namespace std;
 using namespace Gtkmm2ext;
 
+static void *
+_peak_amplitude_thread (void* arg)
+{
+	SessionEvent::create_per_thread_pool ("peak amplitude events", 64);
+	static_cast<AudioRegionEditor*>(arg)->peak_amplitude_thread ();
+	return 0;
+}
+
 AudioRegionEditor::AudioRegionEditor (Session* s, boost::shared_ptr<AudioRegion> r)
 	: RegionEditor (s, r)
 	, _audio_region (r)
 	, gain_adjustment(accurate_coefficient_to_dB(_audio_region->scale_amplitude()), -40.0, +40.0, 0.1, 1.0, 0)	  
-
+	, _peak_amplitude_found (false)
 {
-	gain_label.set_alignment (1, 0.5);
 
-	Gtk::HBox* gb = Gtk::manage (new Gtk::HBox);
-	gb->set_spacing (6);
-	gb->pack_start (gain_entry);
-	gb->pack_start (*Gtk::manage (new Gtk::Label (_("dB"))), false, false);
+	Gtk::HBox* b = Gtk::manage (new Gtk::HBox);
+	b->set_spacing (6);
+	b->pack_start (gain_entry);
+	b->pack_start (*Gtk::manage (new Gtk::Label (_("dB"))), false, false);
 
 	gain_label.set_name ("AudioRegionEditorLabel");
 	gain_label.set_text (_("Region gain:"));
+	gain_label.set_alignment (1, 0.5);
 	gain_entry.configure (gain_adjustment, 0.0, 1);
 	_table.attach (gain_label, 0, 1, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
-	_table.attach (*gb, 1, 2, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
+	_table.attach (*b, 1, 2, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
+	++_table_row;
 
+	b = Gtk::manage (new Gtk::HBox);
+	b->set_spacing (6);
+	b->pack_start (_peak_amplitude);
+	b->pack_start (*Gtk::manage (new Gtk::Label (_("dBFS"))), false, false);
+	
+	_peak_amplitude_label.set_name ("AudioRegionEditorLabel");
+	_peak_amplitude_label.set_text (_("Peak amplitude:"));
+	_peak_amplitude_label.set_alignment (1, 0.5);
+	_table.attach (_peak_amplitude_label, 0, 1, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
+	_table.attach (*b, 1, 2, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
+	++_table_row;
+	
 	gain_changed ();
 
 	gain_adjustment.signal_value_changed().connect (sigc::mem_fun (*this, &AudioRegionEditor::gain_adjustment_changed));
+
+	_peak_amplitude.property_editable() = false;
+	_peak_amplitude.set_text (_("Calculating..."));
+
+	PeakAmplitudeFound.connect (_peak_amplitude_connection, invalidator (*this), boost::bind (&AudioRegionEditor::peak_amplitude_found, this, _1), gui_context ());
+	pthread_create_and_store (X_("peak-amplitude"), &_peak_amplitude_thread_handle, _peak_amplitude_thread, this);
+}
+
+AudioRegionEditor::~AudioRegionEditor ()
+{
+	pthread_cancel_one (_peak_amplitude_thread_handle);
+	void* v;
+	int const r = pthread_join (_peak_amplitude_thread_handle, &v);
+	assert (r == 0);
 }
 
 void
@@ -91,3 +129,16 @@ AudioRegionEditor::gain_adjustment_changed ()
 		_audio_region->set_scale_amplitude (gain);
 	}
 }
+
+void
+AudioRegionEditor::peak_amplitude_thread ()
+{
+	PeakAmplitudeFound (accurate_coefficient_to_dB (_audio_region->maximum_amplitude ())); /* EMIT SIGNAL */
+}
+
+void
+AudioRegionEditor::peak_amplitude_found (double p)
+{
+	_peak_amplitude.set_text (boost::lexical_cast<string> (p));
+}
+
diff --git a/gtk2_ardour/audio_region_editor.h b/gtk2_ardour/audio_region_editor.h
index ee7d6bd54a..f3accaf115 100644
--- a/gtk2_ardour/audio_region_editor.h
+++ b/gtk2_ardour/audio_region_editor.h
@@ -53,7 +53,10 @@ class AudioRegionEditor : public RegionEditor
 {
   public:
 	AudioRegionEditor (ARDOUR::Session*, boost::shared_ptr<ARDOUR::AudioRegion>);
+	~AudioRegionEditor ();
 
+	void peak_amplitude_thread ();
+	
   private:
 
 	void region_changed (PBD::PropertyChange const &);
@@ -66,6 +69,15 @@ class AudioRegionEditor : public RegionEditor
 	Gtk::Label gain_label;
 	Gtk::Adjustment gain_adjustment;
 	Gtk::SpinButton gain_entry;
+
+	Gtk::Label _peak_amplitude_label;
+	Gtk::Entry _peak_amplitude;
+
+	bool _peak_amplitude_found;
+	pthread_t _peak_amplitude_thread_handle;
+	void peak_amplitude_found (double);
+	PBD::Signal1<void, double> PeakAmplitudeFound;
+	PBD::ScopedConnection _peak_amplitude_connection;
 };
 
 #endif /* __gtk_ardour_audio_region_edit_h__ */
diff --git a/gtk2_ardour/region_editor.cc b/gtk2_ardour/region_editor.cc
index 0d3f89dfad..708c789dd0 100755
--- a/gtk2_ardour/region_editor.cc
+++ b/gtk2_ardour/region_editor.cc
@@ -44,7 +44,7 @@ using namespace Gtkmm2ext;
 
 RegionEditor::RegionEditor (Session* s, boost::shared_ptr<Region> r)
 	: ArdourDialog (_("Region")),
-	  _table (8, 2),
+	  _table (9, 2),
 	  _table_row (0),
 	  _region (r),
 	  name_label (_("Name:")),
@@ -88,7 +88,12 @@ RegionEditor::RegionEditor (Session* s, boost::shared_ptr<Region> r)
 	start_label.set_name ("RegionEditorLabel");
 	start_label.set_text (_("File start:"));
 	_sources_label.set_name ("RegionEditorLabel");
-	_sources_label.set_text (_("Sources:"));
+
+	if (region->n_channels() > 1) {
+		_sources_label.set_text (_("Sources:"));
+	} else {
+		_sources_label.set_text (_("Source:"));
+	}
 
 	_table.set_col_spacings (12);
 	_table.set_row_spacings (6);
@@ -139,7 +144,7 @@ RegionEditor::RegionEditor (Session* s, boost::shared_ptr<Region> r)
 	_table.attach (_sources_label, 0, 1, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
 	_table.attach (_sources, 1, 2, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
 	++_table_row;
-
+	
 	get_vbox()->pack_start (_table, true, true);
 
 	add_button (Gtk::Stock::CLOSE, Gtk::RESPONSE_ACCEPT);
diff --git a/gtk2_ardour/region_editor.h b/gtk2_ardour/region_editor.h
index df9df33fc8..66f0f6226d 100644
--- a/gtk2_ardour/region_editor.h
+++ b/gtk2_ardour/region_editor.h
@@ -52,6 +52,7 @@ class RegionEditor : public ArdourDialog
 {
   public:
 	RegionEditor (ARDOUR::Session*, boost::shared_ptr<ARDOUR::Region>);
+	virtual ~RegionEditor () {}
 
   protected:	
 	virtual void region_changed (const PBD::PropertyChange&);
diff --git a/libs/ardour/ardour/audioregion.h b/libs/ardour/ardour/audioregion.h
index 302d1d1698..902e7eb934 100644
--- a/libs/ardour/ardour/audioregion.h
+++ b/libs/ardour/ardour/audioregion.h
@@ -83,7 +83,7 @@ class AudioRegion : public Region
 	gain_t scale_amplitude() const { return _scale_amplitude; }
 
 	void normalize (float, float target_in_dB = 0.0f);
-	double maximum_amplitude (Progress *) const;
+	double maximum_amplitude (Progress* p = 0) const;
 
 	bool envelope_active () const { return _envelope_active; }
 	bool fade_in_active ()  const { return _fade_in_active; }
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index be3b80de87..9d94651eb0 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -1174,9 +1174,11 @@ AudioRegion::maximum_amplitude (Progress* p) const
 		}
 
 		fpos += to_read;
-		p->set_progress (float (fpos - _start) / _length);
-		if (p->cancelled ()) {
-			return -1;
+		if (p) {
+			p->set_progress (float (fpos - _start) / _length);
+			if (p->cancelled ()) {
+				return -1;
+			}
 		}
 	}