Merge branch 'master' into windows

23 files changed, 481 insertions, 461 deletions

diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index 307eb925b3..50a903cf6c 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -388,25 +388,8 @@ ARDOUR_UI::create_global_port_matrix (ARDOUR::DataType type)
 void
 ARDOUR_UI::attach_to_engine ()
 {
-	AudioEngine::instance()->Stopped.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::engine_stopped, this), gui_context());
 	AudioEngine::instance()->Running.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::engine_running, this), gui_context());
-	AudioEngine::instance()->SampleRateChanged.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::update_sample_rate, this, _1), gui_context());
-
-	AudioEngine::instance()->Halted.connect_same_thread (halt_connection, boost::bind (&ARDOUR_UI::engine_halted, this, _1, false));
-
 	ARDOUR::Port::set_connecting_blocked (ARDOUR_COMMAND_LINE::no_connect_ports);
-
-	/* if there is only one audio/midi backend, and it does not require setup, get our use of it underway
-	 * right here (we need to know the client name and potential session ID
-	 * to do this, which is why this is here, rather than in, say,
-	 * ARDOUR::init().
-	 */
-
-	if (!AudioEngine::instance()->setup_required()) {
-		const AudioBackendInfo* backend = AudioEngine::instance()->available_backends().front();
-		AudioEngine::instance()->set_backend (backend->name, ARDOUR_COMMAND_LINE::backend_client_name, ARDOUR_COMMAND_LINE::backend_session_uuid);
-		AudioEngine::instance()->start ();
-	}
 }
 
 void
@@ -528,6 +511,12 @@ ARDOUR_UI::post_engine ()
 	 */
 
 	ARDOUR::init_post_engine ();
+	
+	/* connect to important signals */
+
+	AudioEngine::instance()->Stopped.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::engine_stopped, this), gui_context());
+	AudioEngine::instance()->SampleRateChanged.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::update_sample_rate, this, _1), gui_context());
+	AudioEngine::instance()->Halted.connect_same_thread (halt_connection, boost::bind (&ARDOUR_UI::engine_halted, this, _1, false));
 
 	_tooltips.enable();
 
diff --git a/gtk2_ardour/editor_videotimeline.cc b/gtk2_ardour/editor_videotimeline.cc
index e9360d9d09..ce373f0406 100644
--- a/gtk2_ardour/editor_videotimeline.cc
+++ b/gtk2_ardour/editor_videotimeline.cc
@@ -140,7 +140,7 @@ Editor::export_video ()
 				break;
 		}
 	}
-	ExportVideoDialog dialog (*this, _session);
+	ExportVideoDialog dialog (_session, get_selection().time);
 	Gtk::ResponseType r = (Gtk::ResponseType) dialog.run();
 	dialog.hide();
 #if 0
diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index 873498f6ec..d724f4f4d3 100644
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -29,6 +29,7 @@
 
 #include "pbd/error.h"
 #include "pbd/xml++.h"
+#include "pbd/unwind.h"
 
 #include <gtkmm/stock.h>
 #include <gtkmm/notebook.h>
@@ -95,15 +96,6 @@ EngineControl::EngineControl ()
 	if (audio_setup) {
 		set_state (*audio_setup);
 	} 
-
-	ARDOUR::AudioEngine::instance()->Stopped.connect (*this, MISSING_INVALIDATOR, boost::bind (&EngineControl::disable_latency_tab, this), gui_context());
-
-	if (!ARDOUR::AudioEngine::instance()->connected()) {
-		ARDOUR::AudioEngine::instance()->Running.connect (*this, MISSING_INVALIDATOR, boost::bind (&EngineControl::enable_latency_tab, this), gui_context());
-		disable_latency_tab ();
-	} else {
-		enable_latency_tab ();
-	}
 }
 
 void
@@ -281,9 +273,18 @@ and microphone.\n\n\
 	driver_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::driver_changed));
 	sample_rate_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::sample_rate_changed));
 	buffer_size_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::buffer_size_changed));
+	device_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::device_changed));
+
+	input_latency.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+	output_latency.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+	input_channels.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+	output_channels.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+
+
 	input_channels.signal_output().connect (sigc::bind (sigc::ptr_fun (&EngineControl::print_channel_count), &input_channels));
 	output_channels.signal_output().connect (sigc::bind (sigc::ptr_fun (&EngineControl::print_channel_count), &output_channels));
-	device_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::device_changed));
+
+	notebook.signal_switch_page().connect (sigc::mem_fun (*this, &EngineControl::on_switch_page));
 }
 
 EngineControl::~EngineControl ()
@@ -297,6 +298,8 @@ EngineControl::disable_latency_tab ()
 	vector<string> empty;
 	set_popdown_strings (lm_output_channel_combo, empty);
 	set_popdown_strings (lm_input_channel_combo, empty);
+	lm_measure_button.set_sensitive (false);
+	lm_use_button.set_sensitive (false);
 }
 
 void
@@ -311,6 +314,9 @@ EngineControl::enable_latency_tab ()
 	ARDOUR::AudioEngine::instance()->get_physical_inputs (ARDOUR::DataType::AUDIO, inputs);
 	set_popdown_strings (lm_input_channel_combo, inputs);
 	lm_input_channel_combo.set_active_text (inputs.front());
+
+	lm_measure_button.set_sensitive (true);
+	lm_use_button.set_sensitive (true);
 }
 
 void
@@ -384,10 +390,26 @@ EngineControl::list_devices ()
 	set_popdown_strings (device_combo, available_devices);
 	
 	if (!available_devices.empty()) {
+		sample_rate_combo.set_sensitive (true);
+		buffer_size_combo.set_sensitive (true);
+		input_latency.set_sensitive (true);
+		output_latency.set_sensitive (true);
+		input_channels.set_sensitive (true);
+		output_channels.set_sensitive (true);
+						
+		/* changing the text in the combo will trigger device_changed()
+		   which should populate the parameter controls
+		*/
+		
 		device_combo.set_active_text (available_devices.front());
+	} else {
+		sample_rate_combo.set_sensitive (true);
+		buffer_size_combo.set_sensitive (true);
+		input_latency.set_sensitive (true);
+		output_latency.set_sensitive (true);
+		input_channels.set_sensitive (true);
+		output_channels.set_sensitive (true);
 	}
-
-	device_changed ();
 }
 	
 void
@@ -468,7 +490,13 @@ EngineControl::device_changed ()
 
 	ignore_changes--;
 
+	/* pick up any saved state for this device */
+
 	maybe_display_saved_state ();
+
+	/* and push it to the backend */
+
+	push_state_to_backend (false);
 }	
 
 void 
@@ -483,6 +511,7 @@ EngineControl::sample_rate_changed ()
 	*/
 
 	show_buffer_duration ();
+	push_state_to_backend (false);
 	save_state ();
 
 }
@@ -495,6 +524,7 @@ EngineControl::buffer_size_changed ()
 	}
 
 	show_buffer_duration ();
+	push_state_to_backend (false);
 	save_state ();
 }
 
@@ -522,6 +552,14 @@ EngineControl::show_buffer_duration ()
 	buffer_size_duration_label.set_text (buf);
 }
 
+void
+EngineControl::parameter_changed ()
+{
+	if (!ignore_changes) {
+		save_state ();
+	}
+}
+
 EngineControl::State*
 EngineControl::get_matching_state (const string& backend,
 				   const string& driver,
@@ -538,7 +576,7 @@ EngineControl::get_matching_state (const string& backend,
 }
 
 EngineControl::State*
-EngineControl::get_current_state ()
+EngineControl::get_saved_state_for_currently_displayed_backend_and_device ()
 {
 	boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
 
@@ -554,11 +592,11 @@ EngineControl::get_current_state ()
 				   device_combo.get_active_text());
 }
 
-void
+EngineControl::State*
 EngineControl::save_state ()
 {
 	bool existing = true;
-	State* state = get_current_state ();
+	State* state = get_saved_state_for_currently_displayed_backend_and_device ();
 
 	if (!state) {
 		existing = false;
@@ -578,12 +616,14 @@ EngineControl::save_state ()
 	if (!existing) {
 		states.push_back (*state);
 	}
+
+	return state;
 }
 
 void
 EngineControl::maybe_display_saved_state ()
 {
-	State* state = get_current_state ();
+	State* state = get_saved_state_for_currently_displayed_backend_and_device ();
 
 	if (state) {
 		ignore_changes++;
@@ -792,11 +832,10 @@ EngineControl::push_state_to_backend (bool start)
 		 * necessary
 		 */
 
-		State* state = get_current_state ();
+		State* state = get_saved_state_for_currently_displayed_backend_and_device ();
 
 		if (!state) {
-			save_state ();
-			state = get_current_state ();
+			state = save_state ();
 			assert (state);
 		}
 
@@ -926,23 +965,47 @@ EngineControl::set_desired_sample_rate (uint32_t sr)
 	device_changed ();
 }
 
-/* latency measurement */
-
 void
-EngineControl::update_latency_display ()
+EngineControl::on_switch_page (GtkNotebookPage*, guint page_num)
 {
-	ARDOUR::framecnt_t const sample_rate = ARDOUR::AudioEngine::instance()->sample_rate();
-        if (sample_rate == 0) {
-                lm_results.set_text (_("Disconnected from audio engine"));
-        } else {
-                char buf[64];
-                //snprintf (buf, sizeof (buf), "%10.3lf frames %10.3lf ms",
-		//(float)_pi->latency(), (float)_pi->latency() * 1000.0f/sample_rate);
-		strcpy (buf, "got something");
-                lm_results.set_text(buf);
-        }
+	if (page_num == 2) {
+		/* latency tab */
+
+		if (!ARDOUR::AudioEngine::instance()->running()) {
+			
+			PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+			
+			/* save any existing latency values */
+			
+			uint32_t il = (uint32_t) input_latency.get_value ();
+			uint32_t ol = (uint32_t) input_latency.get_value ();
+
+			/* reset to zero so that our new test instance of JACK
+			   will be clean of any existing latency measures.
+			*/
+			
+			input_latency.set_value (0);
+			output_latency.set_value (0);
+			
+			push_state_to_backend (false);
+
+			/* reset control */
+
+			input_latency.set_value (il);
+			output_latency.set_value (ol);
+		}
+
+		if (ARDOUR::AudioEngine::instance()->prepare_for_latency_measurement()) {
+			disable_latency_tab ();
+		}
+		enable_latency_tab ();
+	} else {
+		ARDOUR::AudioEngine::instance()->stop_latency_detection();
+	}
 }
 
+/* latency measurement */
+
 bool
 EngineControl::check_latency_measurement ()
 {
@@ -974,6 +1037,7 @@ EngineControl::check_latency_measurement ()
         }
 
 	uint32_t frames_total = mtdm->del();
+	cerr << "total = " << frames_total << " delay = " << ARDOUR::AudioEngine::instance()->latency_signal_delay() << endl;
 	uint32_t extra = frames_total - ARDOUR::AudioEngine::instance()->latency_signal_delay();
 
         snprintf (buf, sizeof (buf), "%u samples %10.3lf ms", extra, extra * 1000.0f/sample_rate);
@@ -991,7 +1055,6 @@ EngineControl::check_latency_measurement ()
         }
 
         if (solid) {
-                // _pi->set_measured_latency (rint (mtdm->del()));
                 lm_measure_button.set_active (false);
 		lm_use_button.set_sensitive (true);
                 strcat (buf, " (set)");
@@ -1009,7 +1072,6 @@ EngineControl::latency_button_toggled ()
 
 		ARDOUR::AudioEngine::instance()->set_latency_input_port (lm_input_channel_combo.get_active_text());
 		ARDOUR::AudioEngine::instance()->set_latency_output_port (lm_output_channel_combo.get_active_text());
-		cerr << "latency detection on " << lm_input_channel_combo.get_active_text() << " => " << lm_output_channel_combo.get_active_text() << endl;
 		ARDOUR::AudioEngine::instance()->start_latency_detection ();
                 lm_results.set_text (_("Detecting ..."));
                 latency_timeout = Glib::signal_timeout().connect (mem_fun (*this, &EngineControl::check_latency_measurement), 250);
@@ -1017,7 +1079,6 @@ EngineControl::latency_button_toggled ()
         } else {
 		ARDOUR::AudioEngine::instance()->stop_latency_detection ();
                 latency_timeout.disconnect ();
-                update_latency_display ();
         }
 }
 
diff --git a/gtk2_ardour/engine_dialog.h b/gtk2_ardour/engine_dialog.h
index 3872917add..98ddf2c1b3 100644
--- a/gtk2_ardour/engine_dialog.h
+++ b/gtk2_ardour/engine_dialog.h
@@ -118,6 +118,7 @@ class EngineControl : public ArdourDialog, public PBD::ScopedConnectionList {
     void backend_changed ();
     void sample_rate_changed ();
     void buffer_size_changed ();
+    void parameter_changed ();
 
     uint32_t get_rate() const;
     uint32_t get_buffer_size() const;
@@ -154,9 +155,9 @@ class EngineControl : public ArdourDialog, public PBD::ScopedConnectionList {
     State* get_matching_state (const std::string& backend,
 			       const std::string& driver,
 			       const std::string& device);
-    State* get_current_state ();
+    State* get_saved_state_for_currently_displayed_backend_and_device ();
     void maybe_display_saved_state ();
-    void save_state ();
+    State* save_state ();
 
     static bool print_channel_count (Gtk::SpinButton*);
 
@@ -172,10 +173,11 @@ class EngineControl : public ArdourDialog, public PBD::ScopedConnectionList {
     /* latency measurement */
     void latency_button_toggled ();
     bool check_latency_measurement ();
-    void update_latency_display ();
     sigc::connection latency_timeout;
     void enable_latency_tab ();
     void disable_latency_tab ();
+
+    void on_switch_page (GtkNotebookPage*, guint page_num);
 };
 
 #endif /* __gtk2_ardour_engine_dialog_h__ */
diff --git a/gtk2_ardour/export_video_dialog.cc b/gtk2_ardour/export_video_dialog.cc
index f54232a681..7f6fcc2a8a 100644
--- a/gtk2_ardour/export_video_dialog.cc
+++ b/gtk2_ardour/export_video_dialog.cc
@@ -64,9 +64,9 @@ using namespace PBD;
 using namespace ARDOUR;
 using namespace VideoUtils;
 
-ExportVideoDialog::ExportVideoDialog (PublicEditor& ed, Session* s)
+ExportVideoDialog::ExportVideoDialog (Session* s, TimeSelection &tme)
 	: ArdourDialog (_("Export Video File "))
-	, editor (ed)
+	, export_range (tme)
 	, outfn_path_label (_("File:"), Gtk::ALIGN_LEFT)
 	, outfn_browse_button (_("Browse"))
 	, invid_path_label (_("Video:"), Gtk::ALIGN_LEFT)
@@ -152,6 +152,9 @@ ExportVideoDialog::ExportVideoDialog (PublicEditor& ed, Session* s)
 	} else {
 		insnd_combo.append_text (_("from the video's start to the video's end"));
 	}
+	if (!export_range.empty()) {
+		insnd_combo.append_text (_("Selected range"));  // TODO show export_range.start() -> export_range.end_frame()
+	}
 	insnd_combo.set_active(0);
 
 	outfn_path_entry.set_width_chars(38);
@@ -509,6 +512,11 @@ ExportVideoDialog::launch_export ()
 		}
 		end += av_offset;
 	}
+	else if (insnd_combo.get_active_row_number() == 2) {
+		// TODO quantize to video-frame ?!
+		start = export_range.start();
+		end   = export_range.end_frame();
+	}
 	if (end <= 0) {
 		start = _session->current_start_frame();
 		end   = _session->current_end_frame();
@@ -696,9 +704,14 @@ ExportVideoDialog::encode_pass (int pass)
 	double duration_s  = 0;
 
 	if (insnd_combo.get_active_row_number() == 0) {
+		/* session start to session end */
 		framecnt_t duration_f = _session->current_end_frame() - _session->current_start_frame();
 		duration_s = (double)duration_f / (double)_session->nominal_frame_rate();
+	} else if (insnd_combo.get_active_row_number() == 2) {
+		/* selected range */
+		duration_s = export_range.length() / (double)_session->nominal_frame_rate();
 	} else {
+		/* video start to end */
 		framecnt_t duration_f = ARDOUR_UI::instance()->video_timeline->get_duration();
 		if (av_offset < 0 ) {
 			duration_f += av_offset;
@@ -714,10 +727,16 @@ ExportVideoDialog::encode_pass (int pass)
 		transcoder->set_duration(duration_s * transcoder->get_fps());
 	}
 
-	if (insnd_combo.get_active_row_number() == 0) {
-		const framepos_t start = _session->current_start_frame();
-		const framepos_t snend = _session->current_end_frame();
+	if (insnd_combo.get_active_row_number() == 0 || insnd_combo.get_active_row_number() == 2) {
+		framepos_t start, snend;
 		const frameoffset_t vid_duration = ARDOUR_UI::instance()->video_timeline->get_duration();
+		if (insnd_combo.get_active_row_number() == 0) {
+			start = _session->current_start_frame();
+			snend = _session->current_end_frame();
+		} else {
+			start = export_range.start();
+			snend = export_range.end_frame();
+		}
 
 #if 0 /* DEBUG */
 		printf("AV offset: %lld Vid-len: %lld Vid-end: %lld || start:%lld || end:%lld\n",
@@ -732,9 +751,17 @@ ExportVideoDialog::encode_pass (int pass)
 		} else if (av_offset + vid_duration < snend) {
 			transcoder->set_leadinout(0, (snend - (av_offset + vid_duration)) / (double)_session->nominal_frame_rate());
 			transcoder->set_avoffset((av_offset - start) / (double)_session->nominal_frame_rate());
-		} else {
+		}
+#if 0
+		else if (start > av_offset) {
+			std::ostringstream osstream; osstream << ((start - av_offset) / (double)_session->nominal_frame_rate());
+			ffs["-ss"] = osstream.str();
+		}
+#endif
+		else {
 			transcoder->set_avoffset((av_offset - start) / (double)_session->nominal_frame_rate());
 		}
+
 	} else if (av_offset < 0) {
 		/* from 00:00:00:00 to video-end */
 		transcoder->set_avoffset(av_offset / (double)_session->nominal_frame_rate());
diff --git a/gtk2_ardour/export_video_dialog.h b/gtk2_ardour/export_video_dialog.h
index 2594c2073b..7e3cf442a7 100644
--- a/gtk2_ardour/export_video_dialog.h
+++ b/gtk2_ardour/export_video_dialog.h
@@ -28,6 +28,7 @@
 #include "ardour/template_utils.h"
 #include "ardour_dialog.h"
 
+#include "time_selection.h"
 #include "transcode_ffmpeg.h"
 
 /** @class ExportVideoDialog
@@ -40,13 +41,13 @@
 class ExportVideoDialog : public ArdourDialog , public PBD::ScopedConnectionList
 {
   public:
-	ExportVideoDialog (PublicEditor&, ARDOUR::Session*);
+	ExportVideoDialog (ARDOUR::Session*, TimeSelection &tme);
 	~ExportVideoDialog ();
 
 	std::string get_exported_filename () { return outfn_path_entry.get_text(); }
 
   private:
-	PublicEditor& editor;
+	TimeSelection &export_range;
 
 	void on_show ();
 	void abort_clicked ();
diff --git a/gtk2_ardour/gain_meter.cc b/gtk2_ardour/gain_meter.cc
index d4610da601..f9ab062750 100644
--- a/gtk2_ardour/gain_meter.cc
+++ b/gtk2_ardour/gain_meter.cc
@@ -277,16 +277,19 @@ GainMeterBase::setup_meters (int len)
 
 	switch (_width) {
 		case Wide:
-			meter_ticks1_area.show();
-			meter_ticks2_area.show();
+			//meter_ticks1_area.show();
+			//meter_ticks2_area.show();
 			meter_metric_area.show();
 			if (_route && _route->shared_peak_meter()->input_streams().n_total() == 1) {
 				meter_width = 10;
 			}
 			break;
 		case Narrow:
-			meter_ticks1_area.hide();
-			meter_ticks2_area.hide();
+			if (_route && _route->shared_peak_meter()->input_streams().n_total() > 1) {
+				meter_width = 4;
+			}
+			//meter_ticks1_area.hide();
+			//meter_ticks2_area.hide();
 			meter_metric_area.hide();
 			break;
 	}
diff --git a/gtk2_ardour/utils.cc b/gtk2_ardour/utils.cc
index 28e0907f44..a35d171690 100644
--- a/gtk2_ardour/utils.cc
+++ b/gtk2_ardour/utils.cc
@@ -363,8 +363,15 @@ set_color (Gdk::Color& c, int rgb)
 bool
 relay_key_press (GdkEventKey* ev, Gtk::Window* win)
 {
+	PublicEditor& ed (PublicEditor::instance());
+
+	if (&ed == 0) {
+		/* early key press in pre-main-window-dialogs, no editor yet */
+		return false;
+	}
+
 	if (!key_press_focus_accelerator_handler (*win, ev)) {
-		return PublicEditor::instance().on_key_press_event(ev);
+		return ed.on_key_press_event(ev);
 	} else {
 		return true;
 	}
diff --git a/libs/ardour/ardour/audio_backend.h b/libs/ardour/ardour/audio_backend.h
index 6c4a54da3e..d9561a62e5 100644
--- a/libs/ardour/ardour/audio_backend.h
+++ b/libs/ardour/ardour/audio_backend.h
@@ -29,17 +29,15 @@
 #include <boost/function.hpp>
 
 #include "ardour/types.h"
+#include "ardour/audioengine.h"
+#include "ardour/port_engine.h"
 
 namespace ARDOUR {
 
-class AudioEngine;
-class PortEngine;
-class PortManager;
-
-class AudioBackend {
+class AudioBackend : public PortEngine {
   public:
 
-    AudioBackend (AudioEngine& e) : engine (e){}
+    AudioBackend (AudioEngine& e) : PortEngine (e), engine (e) {}
     virtual ~AudioBackend () {}
 
     /** Return the name of this backend.
@@ -49,17 +47,6 @@ class AudioBackend {
      */
     virtual std::string name() const = 0;
 
-    /** Return a private, type-free pointer to any data
-     * that might be useful to a concrete implementation
-     */
-    virtual void* private_handle() const = 0;
-
-    /** Return true if the underlying mechanism/API is still available
-     * for us to utilize. return false if some or all of the AudioBackend
-     * API can no longer be effectively used.
-     */
-    virtual bool connected() const = 0;
-
     /** Return true if the callback from the underlying mechanism/API
      * (CoreAudio, JACK, ASIO etc.) occurs in a thread subject to realtime
      * constraints. Return false otherwise.
@@ -416,11 +403,22 @@ class AudioBackend {
 struct AudioBackendInfo {
     const char* name;
 
+    /** Using arg1 and arg2, initialize this audiobackend.
+     * 
+     * Returns zero on success, non-zero otherwise.
+     */
     int (*instantiate) (const std::string& arg1, const std::string& arg2);
+
+    /** Release all resources associated with this audiobackend
+     */
     int (*deinstantiate) (void);
 
-    boost::shared_ptr<AudioBackend> (*backend_factory) (AudioEngine&);
-    boost::shared_ptr<PortEngine> (*portengine_factory) (PortManager&);
+    /** Factory method to create an AudioBackend-derived class.
+     * 
+     * Returns a valid shared_ptr to the object if successfull,
+     * or a "null" shared_ptr otherwise.
+     */
+    boost::shared_ptr<AudioBackend> (*factory) (AudioEngine&);
 
     /** Return true if the underlying mechanism/API has been
      * configured and does not need (re)configuration in order
diff --git a/libs/ardour/ardour/audioengine.h b/libs/ardour/ardour/audioengine.h
index 21206da8fc..201d960479 100644
--- a/libs/ardour/ardour/audioengine.h
+++ b/libs/ardour/ardour/audioengine.h
@@ -188,6 +188,7 @@ public:
     /* latency measurement */
 
     MTDM* mtdm();
+    int  prepare_for_latency_measurement ();
     void start_latency_detection ();
     void stop_latency_detection ();
     void set_latency_input_port (const std::string&);
@@ -199,8 +200,6 @@ public:
 
     static AudioEngine*       _instance;
 
-    boost::shared_ptr<AudioBackend> _backend;
-
     Glib::Threads::Mutex      _process_lock;
     Glib::Threads::Cond        session_removed;
     bool                       session_remove_pending;
@@ -225,6 +224,7 @@ public:
     std::string               _latency_input_name;
     std::string               _latency_output_name;
     framecnt_t                _latency_signal_latency;
+    bool                      _started_for_latency;
 
     void meter_thread ();
     void start_metering_thread ();
diff --git a/libs/ardour/ardour/port_engine.h b/libs/ardour/ardour/port_engine.h
index 71f93ea05e..8c0ec9e754 100644
--- a/libs/ardour/ardour/port_engine.h
+++ b/libs/ardour/ardour/port_engine.h
@@ -79,6 +79,11 @@ class PortEngine {
     PortEngine (PortManager& pm) : manager (pm) {}
     virtual ~PortEngine() {}
     
+    /** Return a private, type-free pointer to any data
+     * that might be useful to a concrete implementation
+     */
+    virtual void* private_handle() const = 0;
+
     /* We use void* here so that the API can be defined for any implementation.
      * 
      * We could theoretically use a template (PortEngine<T>) and define
@@ -89,21 +94,16 @@ class PortEngine {
        
     typedef void* PortHandle;
 
-    /** Return a typeless pointer to an object that may be of interest
-     * that understands the internals of a particular PortEngine
-     * implementation.
-     *
-     * XXX the existence of this method is a band-aid over some design
-     * issues and will it will be removed in the future
-     */
-    virtual void* private_handle() const = 0;
-
-    virtual bool connected() const = 0;
-
     /** Return the name of this process as used by the port manager
      * when naming ports.
      */
     virtual const std::string& my_name() const = 0;
+ 
+    /** Return true if the underlying mechanism/API is still available
+     * for us to utilize. return false if some or all of the AudioBackend
+     * API can no longer be effectively used.
+     */
+    virtual bool available() const = 0;
 
     /** Return the maximum size of a port name 
      */
diff --git a/libs/ardour/ardour/port_manager.h b/libs/ardour/ardour/port_manager.h
index 6d45597a41..ba15142d83 100644
--- a/libs/ardour/ardour/port_manager.h
+++ b/libs/ardour/ardour/port_manager.h
@@ -34,10 +34,12 @@
 #include "ardour/chan_count.h"
 #include "ardour/midiport_manager.h"
 #include "ardour/port.h"
-#include "ardour/port_engine.h"
 
 namespace ARDOUR {
 
+class PortEngine;
+class AudioBackend;
+
 class PortManager 
 {
   public:
@@ -47,8 +49,7 @@ class PortManager
     PortManager ();
     virtual ~PortManager() {}
 
-    void set_port_engine (PortEngine& pe);
-    PortEngine& port_engine() { return *_impl; }
+    PortEngine& port_engine();
 
     uint32_t port_name_size() const;
     std::string my_name() const;
@@ -134,7 +135,7 @@ class PortManager
     PBD::Signal5<void, boost::weak_ptr<Port>, std::string, boost::weak_ptr<Port>, std::string, bool> PortConnectedOrDisconnected;
 
   protected:
-    boost::shared_ptr<PortEngine> _impl;
+    boost::shared_ptr<AudioBackend> _backend;
     SerializedRCUManager<Ports> ports;
     bool _port_remove_in_progress;
 
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 43660d41cc..d0cd3fa06e 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1624,6 +1624,7 @@ class Session : public PBD::StatefulDestructible, public PBD::ScopedConnectionLi
     void setup_ltc ();
     void setup_click ();
     void setup_bundles ();
+    int  ensure_engine (uint32_t desired_sample_rate);
 };
 
 } // namespace ARDOUR
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index ded8bf39b5..63bed97ecc 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -78,6 +78,7 @@ AudioEngine::AudioEngine ()
 	, _latency_output_port (0)
 	, _latency_flush_frames (0)
 	, _latency_signal_latency (0)
+	, _started_for_latency (false)
 {
 	g_atomic_int_set (&m_meter_exit, 0);
 	discover_backends ();
@@ -200,6 +201,13 @@ AudioEngine::process_callback (pframes_t nframes)
 	bool return_after_remove_check = false;
 
 	if (_measuring_latency && _mtdm) {
+		/* run a normal cycle from the perspective of the PortManager
+		   so that we get silence on all registered ports.
+		   
+		   we overwrite the silence on the two ports used for latency
+		   measurement.
+		*/
+		
 		PortManager::cycle_start (nframes);
 		PortManager::silence (nframes);
 
@@ -415,8 +423,6 @@ AudioEngine::remove_session ()
 
 	if (_running) {
 
-		stop_metering_thread ();
-
 		if (_session) {
 			session_remove_pending = true;
 			session_removal_countdown = 0;
@@ -564,8 +570,7 @@ AudioEngine::set_backend (const std::string& name, const std::string& arg1, cons
 			throw failed_constructor ();
 		}
 
-		_backend = b->second->backend_factory (*this);
-		_impl = b->second->portengine_factory (*this);
+		_backend = b->second->factory (*this);
 
 	} catch (exception& e) {
 		error << string_compose (_("Could not create backend for %1: %2"), name, e.what()) << endmsg;
@@ -607,7 +612,9 @@ AudioEngine::start ()
 	
 	start_metering_thread ();
 	
-	Running(); /* EMIT SIGNAL */
+	if (!_started_for_latency) {
+		Running(); /* EMIT SIGNAL */
+	}
 	
 	return 0;
 }
@@ -630,6 +637,7 @@ AudioEngine::stop ()
 	_measuring_latency = false;
 	_latency_output_port = 0;
 	_latency_input_port = 0;
+	_started_for_latency = false;
 	stop_metering_thread ();
 	
 	Port::PortDrop ();
@@ -693,7 +701,7 @@ AudioEngine::connected() const
 		return false;
 	}
 
-	return _backend->connected();
+	return _backend->available();
 }
 
 void
@@ -980,6 +988,13 @@ AudioEngine::halted_callback (const char* why)
 bool
 AudioEngine::setup_required () const
 {
+	/* If there is only a single backend and it claims to be configured
+	 * already there is no setup to be done.
+	 *
+	 * Primarily for a case where there is only a JACK backend and
+	 * JACK is already running.
+	 */
+	 
 	if (_backends.size() == 1 && _backends.begin()->second->already_configured()) {
 		return false;
 	}
@@ -993,9 +1008,28 @@ AudioEngine::mtdm()
 	return _mtdm;
 }
 
+int
+AudioEngine::prepare_for_latency_measurement ()
+{
+	if (!running()) {
+		_started_for_latency = true;
+
+		if (start()) {
+			_started_for_latency = false;
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
 void
 AudioEngine::start_latency_detection ()
 {
+	if (prepare_for_latency_measurement ()) {
+		return;
+	}
+
 	PortEngine& pe (port_engine());
 
 	delete _mtdm;
@@ -1027,23 +1061,25 @@ AudioEngine::start_latency_detection ()
 	lr = pe.get_latency_range (_latency_output_port, true);
 	_latency_signal_latency += lr.max;
 
-	cerr << "latency signal pathway = " << _latency_signal_latency << endl;
-	
 	/* all created and connected, lets go */
 
 	_mtdm = new MTDM (sample_rate());
 	_measuring_latency = true;
         _latency_flush_frames = samples_per_cycle();
 
-
 }
 
 void
 AudioEngine::stop_latency_detection ()
 {
+	_measuring_latency = false;
+
 	port_engine().unregister_port (_latency_output_port);
 	port_engine().unregister_port (_latency_input_port);
-	_measuring_latency = false;
+	
+	if (_started_for_latency) {
+		stop ();
+	}
 }
 
 void
diff --git a/libs/ardour/port.cc b/libs/ardour/port.cc
index d8a32e3467..bc5d26fb80 100644
--- a/libs/ardour/port.cc
+++ b/libs/ardour/port.cc
@@ -124,7 +124,7 @@ Port::disconnect_all ()
 bool
 Port::connected_to (std::string const & o) const
 {
-	if (!port_engine.connected()) {
+	if (!port_engine.available()) {
 		return false;
 	}
 
@@ -134,7 +134,7 @@ Port::connected_to (std::string const & o) const
 int
 Port::get_connections (std::vector<std::string> & c) const
 {
-	if (!port_engine.connected()) {
+	if (!port_engine.available()) {
 		c.insert (c.end(), _connections.begin(), _connections.end());
 		return c.size();
 	}
diff --git a/libs/ardour/port_manager.cc b/libs/ardour/port_manager.cc
index 1758ea4a3f..c7adefc531 100644
--- a/libs/ardour/port_manager.cc
+++ b/libs/ardour/port_manager.cc
@@ -20,11 +20,12 @@
 #include "pbd/error.h"
 
 #include "ardour/async_midi_port.h"
-#include "ardour/debug.h"
-#include "ardour/port_manager.h"
+#include "ardour/audio_backend.h"
 #include "ardour/audio_port.h"
+#include "ardour/debug.h"
 #include "ardour/midi_port.h"
 #include "ardour/midiport_manager.h"
+#include "ardour/port_manager.h"
 
 #include "i18n.h"
 
@@ -68,13 +69,13 @@ PortManager::remove_all_ports ()
 string
 PortManager::make_port_name_relative (const string& portname) const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return portname;
 	}
 
 	string::size_type len;
 	string::size_type n;
-	string self = _impl->my_name();
+	string self = _backend->my_name();
 
 	len = portname.length();
 
@@ -100,7 +101,7 @@ PortManager::make_port_name_non_relative (const string& portname) const
 		return portname;
 	}
 
-	str  = _impl->my_name();
+	str  = _backend->my_name();
 	str += ':';
 	str += portname;
 
@@ -110,11 +111,11 @@ PortManager::make_port_name_non_relative (const string& portname) const
 bool
 PortManager::port_is_mine (const string& portname) const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return true;
 	}
 
-	string self = _impl->my_name();
+	string self = _backend->my_name();
 
 	if (portname.find_first_of (':') != string::npos) {
 		if (portname.substr (0, self.length ()) != self) {
@@ -128,54 +129,54 @@ PortManager::port_is_mine (const string& portname) const
 bool
 PortManager::port_is_physical (const std::string& portname) const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return false;
 	}
 
-	PortEngine::PortHandle ph = _impl->get_port_by_name (portname);
+	PortEngine::PortHandle ph = _backend->get_port_by_name (portname);
 	if (!ph) {
 		return false;
 	}
 
-	return _impl->port_is_physical (ph);
+	return _backend->port_is_physical (ph);
 }
 
 void
 PortManager::get_physical_outputs (DataType type, std::vector<std::string>& s)
 {
-	if (!_impl) {
+	if (!_backend) {
 		return;
 	}
-	_impl->get_physical_outputs (type, s);
+	_backend->get_physical_outputs (type, s);
 }
  
 void
 PortManager::get_physical_inputs (DataType type, std::vector<std::string>& s)
 {
-	if (!_impl) {
+	if (!_backend) {
 		return;
 	}
 
-	_impl->get_physical_inputs (type, s);
+	_backend->get_physical_inputs (type, s);
 }
  
 ChanCount
 PortManager::n_physical_outputs () const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return ChanCount::ZERO;
 	}
 
-	return _impl->n_physical_outputs ();
+	return _backend->n_physical_outputs ();
 }
  
 ChanCount
 PortManager::n_physical_inputs () const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return ChanCount::ZERO;
 	}
-	return _impl->n_physical_inputs ();
+	return _backend->n_physical_inputs ();
 }
 
 /** @param name Full or short name of port
@@ -185,7 +186,7 @@ PortManager::n_physical_inputs () const
 boost::shared_ptr<Port>
 PortManager::get_port_by_name (const string& portname)
 {
-	if (!_impl) {
+	if (!_backend) {
 		return boost::shared_ptr<Port>();
 	}
 
@@ -204,7 +205,7 @@ PortManager::get_port_by_name (const string& portname)
 		   and cheap), and if so, rename the port (which will alter
 		   the port map as a side effect).
 		*/
-		const std::string check = make_port_name_relative (_impl->get_port_name (x->second->port_handle()));
+		const std::string check = make_port_name_relative (_backend->get_port_name (x->second->port_handle()));
 		if (check != rel) {
 			x->second->set_name (check);
 		}
@@ -243,26 +244,26 @@ PortManager::get_ports (DataType type, PortList& pl)
 int
 PortManager::get_ports (const string& port_name_pattern, DataType type, PortFlags flags, vector<string>& s)
 {
-	if (!_impl) {
+	if (!_backend) {
 		return 0;
 	}
 
-	return _impl->get_ports (port_name_pattern, type, flags, s);
+	return _backend->get_ports (port_name_pattern, type, flags, s);
 }
 
 void
 PortManager::port_registration_failure (const std::string& portname)
 {
-	if (!_impl) {
+	if (!_backend) {
 		return;
 	}
 
-	string full_portname = _impl->my_name();
+	string full_portname = _backend->my_name();
 	full_portname += ':';
 	full_portname += portname;
 
 
-	PortEngine::PortHandle p = _impl->get_port_by_name (full_portname);
+	PortEngine::PortHandle p = _backend->get_port_by_name (full_portname);
 	string reason;
 
 	if (p) {
@@ -356,17 +357,17 @@ PortManager::unregister_port (boost::shared_ptr<Port> port)
 bool
 PortManager::connected (const string& port_name)
 {
-	if (!_impl) {
+	if (!_backend) {
 		return false;
 	}
 
-	PortEngine::PortHandle handle = _impl->get_port_by_name (port_name);
+	PortEngine::PortHandle handle = _backend->get_port_by_name (port_name);
 
 	if (!handle) {
 		return false;
 	}
 
-	return _impl->connected (handle);
+	return _backend->connected (handle);
 }
 
 int
@@ -387,8 +388,8 @@ PortManager::connect (const string& source, const string& destination)
 	} else {
 		/* neither port is known to us ...hand-off to the PortEngine
 		 */
-		if (_impl) {
-			ret = _impl->connect (s, d);
+		if (_backend) {
+			ret = _backend->connect (s, d);
 		} else {
 			ret = -1;
 		}
@@ -423,8 +424,8 @@ PortManager::disconnect (const string& source, const string& destination)
 	} else {
 		/* neither port is known to us ...hand-off to the PortEngine
 		 */
-		if (_impl) {
-			ret = _impl->disconnect (s, d);
+		if (_backend) {
+			ret = _backend->disconnect (s, d);
 		} else {
 			ret = -1;
 		}
@@ -516,59 +517,59 @@ PortManager::registration_callback ()
 bool
 PortManager::can_request_input_monitoring () const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return false;
 	}
 
-	return _impl->can_monitor_input ();
+	return _backend->can_monitor_input ();
 }
  
 void
 PortManager::request_input_monitoring (const string& name, bool yn) const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return;
 	}
 
-	PortEngine::PortHandle ph = _impl->get_port_by_name (name);
+	PortEngine::PortHandle ph = _backend->get_port_by_name (name);
 
 	if (ph) {
-		_impl->request_input_monitoring (ph, yn);
+		_backend->request_input_monitoring (ph, yn);
 	}
 }
  
 void
 PortManager::ensure_input_monitoring (const string& name, bool yn) const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return;
 	}
 
-	PortEngine::PortHandle ph = _impl->get_port_by_name (name);
+	PortEngine::PortHandle ph = _backend->get_port_by_name (name);
 
 	if (ph) {
-		_impl->ensure_input_monitoring (ph, yn);
+		_backend->ensure_input_monitoring (ph, yn);
 	}
 }
 
 uint32_t
 PortManager::port_name_size() const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return 0;
 	}
 	
-	return _impl->port_name_size ();
+	return _backend->port_name_size ();
 }
 
 string
 PortManager::my_name() const
 {
-	if (!_impl) {
+	if (!_backend) {
 		return string();
 	}
 	
-	return _impl->my_name();
+	return _backend->my_name();
 }
 
 int
@@ -657,3 +658,10 @@ PortManager::fade_out (gain_t base_gain, gain_t gain_step, pframes_t nframes)
 		}
 	}
 }
+
+PortEngine&
+PortManager::port_engine()
+{
+	assert (_backend);
+	return *_backend;
+}
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 135df7c2cd..4be42c769a 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -285,23 +285,10 @@ Session::Session (AudioEngine &eng,
 			}
 		}
 	}
-	
-	if (_engine.current_backend() == 0 || _engine.setup_required()) {
-		boost::optional<int> r = AudioEngineSetupRequired (sr);
-		if (r.get_value_or (-1) != 0) {
-			destroy ();
-			throw failed_constructor();
-		}
-	}
-
-	/* at this point the engine should be connected (i.e. interacting
-	   with a backend device (or psuedo-device) and available to us
-	   for determinining sample rates and other settings.
-	*/
 
-	if (!_engine.connected()) {
+	if (ensure_engine (sr)) {
 		destroy ();
-		throw failed_constructor();
+		throw failed_constructor ();
 	}
 
 	if (post_engine_init ()) {
@@ -346,6 +333,37 @@ Session::~Session ()
 	destroy ();
 }
 
+int
+Session::ensure_engine (uint32_t desired_sample_rate)
+{
+	if (_engine.current_backend() == 0) {
+		/* backend is unknown ... */
+		boost::optional<int> r = AudioEngineSetupRequired (desired_sample_rate);
+		if (r.get_value_or (-1) != 0) {
+			return -1;
+		}
+	} else if (_engine.setup_required()) {
+		/* backend is known, but setup is needed */
+		boost::optional<int> r = AudioEngineSetupRequired (desired_sample_rate);
+		if (r.get_value_or (-1) != 0) {
+			return -1;
+		}
+	} else if (!_engine.running()) {
+		if (_engine.start()) {
+			return -1;
+		}
+	}
+
+	/* at this point the engine should be running
+	*/
+
+	if (!_engine.running()) {
+		return -1;
+	}
+
+	return 0;
+}
+
 void
 Session::destroy ()
 {
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 64f8e387be..88a8a2ae04 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -309,6 +309,8 @@ Session::post_engine_init ()
 
 	_state_of_the_state = Clean;
 
+	Port::set_connecting_blocked (false);
+
 	DirtyChanged (); /* EMIT SIGNAL */
 
 	if (_is_new) {
diff --git a/libs/backends/jack/jack_api.cc b/libs/backends/jack/jack_api.cc
index 0136161181..e02ccde2f1 100644
--- a/libs/backends/jack/jack_api.cc
+++ b/libs/backends/jack/jack_api.cc
@@ -19,12 +19,10 @@
 
 #include "jack_connection.h"
 #include "jack_audiobackend.h"
-#include "jack_portengine.h"
 
 using namespace ARDOUR;
 
 static boost::shared_ptr<JACKAudioBackend> backend;
-static boost::shared_ptr<JACKPortEngine> port_engine;
 static boost::shared_ptr<JackConnection> jack_connection;
 
 static boost::shared_ptr<AudioBackend>
@@ -41,20 +39,6 @@ backend_factory (AudioEngine& ae)
 	return backend;
 }
 
-static boost::shared_ptr<PortEngine>
-portengine_factory (PortManager& pm)
-{
-	if (!jack_connection) {
-		return boost::shared_ptr<PortEngine>();
-	}
-
-	if (!port_engine) {
-		port_engine.reset (new JACKPortEngine (pm, jack_connection));
-	}
-
-	return port_engine;
-}
-
 static int
 instantiate (const std::string& arg1, const std::string& arg2)
 {
@@ -70,7 +54,6 @@ instantiate (const std::string& arg1, const std::string& arg2)
 static int 
 deinstantiate ()
 {
-	port_engine.reset ();
 	backend.reset ();
 	jack_connection.reset ();
 
@@ -95,7 +78,6 @@ extern "C" {
 		instantiate,
 		deinstantiate,
 		backend_factory,
-		portengine_factory,
 		already_configured,
 	};
 }
diff --git a/libs/backends/jack/jack_audiobackend.cc b/libs/backends/jack/jack_audiobackend.cc
index 89a93a76f6..c9bc2ad8ac 100644
--- a/libs/backends/jack/jack_audiobackend.cc
+++ b/libs/backends/jack/jack_audiobackend.cc
@@ -36,7 +36,6 @@
 
 #include "jack_audiobackend.h"
 #include "jack_connection.h"
-#include "jack_portengine.h"
 #include "jack_utils.h"
 
 #include "i18n.h"
@@ -67,6 +66,7 @@ JACKAudioBackend::JACKAudioBackend (AudioEngine& e, boost::shared_ptr<JackConnec
 	, _current_sample_rate (0)
 	, _current_buffer_size (0)
 {
+	_jack_connection->Connected.connect_same_thread (jack_connection_connection, boost::bind (&JACKAudioBackend::when_connected_to_jack, this));
 	_jack_connection->Disconnected.connect_same_thread (disconnect_connection, boost::bind (&JACKAudioBackend::disconnected, this, _1));
 }
 
@@ -87,7 +87,7 @@ JACKAudioBackend::private_handle() const
 }
 
 bool
-JACKAudioBackend::connected() const
+JACKAudioBackend::available() const
 {
 	return (private_handle() != 0);
 }
@@ -158,7 +158,7 @@ JACKAudioBackend::available_sample_rates (const string& /*device*/) const
 {
 	vector<float> f;
 	
-	if (connected()) {
+	if (available()) {
 		f.push_back (sample_rate());
 		return f;
 	}
@@ -186,7 +186,7 @@ JACKAudioBackend::available_buffer_sizes (const string& /*device*/) const
 {
 	vector<uint32_t> s;
 	
-	if (connected()) {
+	if (available()) {
 		s.push_back (buffer_size());
 		return s;
 	}
@@ -223,7 +223,7 @@ JACKAudioBackend::available_output_channel_count (const string& /*device*/) cons
 int
 JACKAudioBackend::set_device_name (const string& dev)
 {
-	if (connected()) {
+	if (available()) {
 		/* need to stop and restart JACK for this to work, at present */
 		return -1;
 	}
@@ -235,7 +235,7 @@ JACKAudioBackend::set_device_name (const string& dev)
 int
 JACKAudioBackend::set_sample_rate (float sr)
 {
-	if (!connected()) {
+	if (!available()) {
 		_target_sample_rate = sr;
 		return 0;
 	}
@@ -252,7 +252,7 @@ JACKAudioBackend::set_sample_rate (float sr)
 int
 JACKAudioBackend::set_buffer_size (uint32_t nframes)
 {
-	if (!connected()) {
+	if (!available()) {
 		_target_buffer_size = nframes;
 		return 0;
 	}
@@ -293,7 +293,7 @@ JACKAudioBackend::set_interleaved (bool yn)
 int
 JACKAudioBackend::set_input_channels (uint32_t cnt)
 {
-	if (connected()) {
+	if (available()) {
 		return -1;
 	}
 
@@ -305,7 +305,7 @@ JACKAudioBackend::set_input_channels (uint32_t cnt)
 int
 JACKAudioBackend::set_output_channels (uint32_t cnt)
 {
-	if (connected()) {
+	if (available()) {
 		return -1;
 	}
 
@@ -317,7 +317,7 @@ JACKAudioBackend::set_output_channels (uint32_t cnt)
 int
 JACKAudioBackend::set_systemic_input_latency (uint32_t l)
 {
-	if (connected()) {
+	if (available()) {
 		return -1;
 	}
 
@@ -329,7 +329,7 @@ JACKAudioBackend::set_systemic_input_latency (uint32_t l)
 int
 JACKAudioBackend::set_systemic_output_latency (uint32_t l)
 {
-	if (connected()) {
+	if (available()) {
 		return -1;
 	}
 
@@ -343,7 +343,7 @@ JACKAudioBackend::set_systemic_output_latency (uint32_t l)
 std::string
 JACKAudioBackend::device_name () const
 {
-	if (connected()) {
+	if (available()) {
 		return "???";
 	} 
 
@@ -353,7 +353,7 @@ JACKAudioBackend::device_name () const
 float
 JACKAudioBackend::sample_rate () const
 {
-	if (connected()) {
+	if (available()) {
 		return _current_sample_rate;
 	}
 	return _target_sample_rate;
@@ -362,7 +362,7 @@ JACKAudioBackend::sample_rate () const
 uint32_t
 JACKAudioBackend::buffer_size () const
 {
-	if (connected()) {
+	if (available()) {
 		return _current_buffer_size;
 	}
 	return _target_buffer_size;
@@ -383,7 +383,7 @@ JACKAudioBackend::interleaved () const
 uint32_t
 JACKAudioBackend::input_channels () const
 {
-	if (connected()) {
+	if (available()) {
 		return n_physical (JackPortIsInput).n_audio();
 	} 
 	return _target_input_channels;
@@ -392,7 +392,7 @@ JACKAudioBackend::input_channels () const
 uint32_t
 JACKAudioBackend::output_channels () const
 {
-	if (connected()) {
+	if (available()) {
 		return n_physical (JackPortIsOutput).n_audio();
 	} 
 	return _target_output_channels;
@@ -451,7 +451,9 @@ JACKAudioBackend::setup_jack_startup_command ()
 	string cmdline;
 
 	if (!get_jack_command_line_string (options, cmdline)) {
-		/* error, somehow */
+		/* error, somehow - we will still try to start JACK
+		 * automatically but it will be without our preferred options
+		 */
 		return;
 	}
 
@@ -465,7 +467,7 @@ JACKAudioBackend::setup_jack_startup_command ()
 int
 JACKAudioBackend::start ()
 {
-	if (!connected()) {
+	if (!available()) {
 
 		if (!_jack_connection->server_running()) {
 			setup_jack_startup_command ();
@@ -736,9 +738,9 @@ JACKAudioBackend::jack_sync_callback (jack_transport_state_t state, jack_positio
 int
 JACKAudioBackend::_xrun_callback (void *arg)
 {
-	JACKAudioBackend* ae = static_cast<JACKAudioBackend*> (arg);
-	if (ae->connected()) {
-		ae->engine.Xrun (); /* EMIT SIGNAL */
+	JACKAudioBackend* jab = static_cast<JACKAudioBackend*> (arg);
+	if (jab->available()) {
+		jab->engine.Xrun (); /* EMIT SIGNAL */
 	}
 	return 0;
 }
@@ -747,8 +749,8 @@ JACKAudioBackend::_xrun_callback (void *arg)
 void
 JACKAudioBackend::_session_callback (jack_session_event_t *event, void *arg)
 {
-	JACKAudioBackend* ae = static_cast<JACKAudioBackend*> (arg);
-	ARDOUR::Session* session = ae->engine.session();
+	JACKAudioBackend* jab = static_cast<JACKAudioBackend*> (arg);
+	ARDOUR::Session* session = jab->engine.session();
 
 	if (session) {
 		session->jack_session_event (event);
@@ -940,8 +942,10 @@ JACKAudioBackend::n_physical (unsigned long flags) const
 	if (ports) {
 		for (uint32_t i = 0; ports[i]; ++i) {
 			if (!strstr (ports[i], "Midi-Through")) {
-				DataType t (jack_port_type (jack_port_by_name (_priv_jack, ports[i])));
-				c.set (t, c.get (t) + 1);
+				DataType t = port_data_type (jack_port_by_name (_priv_jack, ports[i]));
+				if (t != DataType::NIL) {
+					c.set (t, c.get (t) + 1);
+				}
 			}
 		}
 		
diff --git a/libs/backends/jack/jack_audiobackend.h b/libs/backends/jack/jack_audiobackend.h
index 61f1bbb602..655c939c51 100644
--- a/libs/backends/jack/jack_audiobackend.h
+++ b/libs/backends/jack/jack_audiobackend.h
@@ -44,10 +44,12 @@ class JACKAudioBackend : public AudioBackend {
   public:
     JACKAudioBackend (AudioEngine& e, boost::shared_ptr<JackConnection>);
     ~JACKAudioBackend ();
+    
+    /* AUDIOBACKEND API */
 
     std::string name() const;
     void* private_handle() const;
-    bool connected() const;
+    bool available() const;
     bool is_realtime () const;
 
     bool requires_driver_selection() const;
@@ -115,9 +117,68 @@ class JACKAudioBackend : public AudioBackend {
     void update_latencies ();
 
     static bool already_configured();
+    
+    /* PORTENGINE API */
+
+    const std::string& my_name() const;
+    uint32_t port_name_size() const;
+
+    int         set_port_name (PortHandle, const std::string&);
+    std::string get_port_name (PortHandle) const;
+    PortHandle* get_port_by_name (const std::string&) const;
+
+    int get_ports (const std::string& port_name_pattern, DataType type, PortFlags flags, std::vector<std::string>&) const;
+
+    DataType port_data_type (PortHandle) const;
+
+    PortHandle register_port (const std::string& shortname, ARDOUR::DataType, ARDOUR::PortFlags);
+    void  unregister_port (PortHandle);
+
+    bool  connected (PortHandle, bool process_callback_safe);
+    bool  connected_to (PortHandle, const std::string&, bool process_callback_safe);
+    bool  physically_connected (PortHandle, bool process_callback_safe);
+    int   get_connections (PortHandle, std::vector<std::string>&, bool process_callback_safe);
+    int   connect (PortHandle, const std::string&);
+
+    int   disconnect (PortHandle, const std::string&);
+    int   disconnect_all (PortHandle);
+    int   connect (const std::string& src, const std::string& dst);
+    int   disconnect (const std::string& src, const std::string& dst);
+    
+    /* MIDI */
+
+    int      midi_event_get (pframes_t& timestamp, size_t& size, uint8_t** buf, void* port_buffer, uint32_t event_index);
+    int      midi_event_put (void* port_buffer, pframes_t timestamp, const uint8_t* buffer, size_t size);
+    uint32_t get_midi_event_count (void* port_buffer);
+    void     midi_clear (void* port_buffer);
+
+    /* Monitoring */
+
+    bool  can_monitor_input() const;
+    int   request_input_monitoring (PortHandle, bool);
+    int   ensure_input_monitoring (PortHandle, bool);
+    bool  monitoring_input (PortHandle);
+
+    /* Latency management
+     */
+    
+    void          set_latency_range (PortHandle, bool for_playback, LatencyRange);
+    LatencyRange  get_latency_range (PortHandle, bool for_playback);
+
+    /* Physical ports */
+
+    bool      port_is_physical (PortHandle) const;
+    void      get_physical_outputs (DataType type, std::vector<std::string>&);
+    void      get_physical_inputs (DataType type, std::vector<std::string>&);
+    ChanCount n_physical_outputs () const;
+    ChanCount n_physical_inputs () const;
+
+    /* Getting access to the data buffer for a port */
+
+    void* get_buffer (PortHandle, pframes_t);
 
   private:
-    boost::shared_ptr<JackConnection>  _jack_connection; //< shared with JACKPortEngine
+    boost::shared_ptr<JackConnection>  _jack_connection;
     bool            _running;
     bool            _freewheeling;
     std::map<DataType,size_t> _raw_buffer_sizes;
@@ -158,8 +219,6 @@ class JACKAudioBackend : public AudioBackend {
     void*  process_thread ();
     static void* _start_process_thread (void*);
 
-    ChanCount n_physical (unsigned long) const;
-    
     void setup_jack_startup_command ();
 
     /* pffooo */
@@ -183,6 +242,20 @@ class JACKAudioBackend : public AudioBackend {
     mutable DriverDeviceMap all_devices;
 
     PBD::ScopedConnection disconnect_connection;
+
+    /* PORTENGINE RELATED */
+
+    static int  _graph_order_callback (void *arg);
+    static void _registration_callback (jack_port_id_t, int, void *);
+    static void _connect_callback (jack_port_id_t, jack_port_id_t, int, void *);
+
+    void connect_callback (jack_port_id_t, jack_port_id_t, int);
+
+    ChanCount n_physical (unsigned long flags) const;
+    void get_physical (DataType type, unsigned long flags, std::vector<std::string>& phy) const;
+
+    void when_connected_to_jack ();
+    PBD::ScopedConnection jack_connection_connection;
 };
 
 } // namespace
diff --git a/libs/backends/jack/jack_portengine.cc b/libs/backends/jack/jack_portengine.cc
index bd352a2f11..0d66f50448 100644
--- a/libs/backends/jack/jack_portengine.cc
+++ b/libs/backends/jack/jack_portengine.cc
@@ -22,8 +22,9 @@
 
 #include "pbd/error.h"
 
-#include "jack_portengine.h"
+#include "jack_audiobackend.h"
 #include "jack_connection.h"
+#include "jack/midiport.h"
 
 #include "ardour/port_manager.h"
 
@@ -85,24 +86,8 @@ ardour_data_type_to_jack_port_type (DataType d)
 	return "";
 }
 
-JACKPortEngine::JACKPortEngine (PortManager& pm, boost::shared_ptr<JackConnection> jc)
-	: PortEngine (pm)
-	, _jack_connection (jc)
-{
-	_jack_connection->Connected.connect_same_thread (jack_connection_connection, boost::bind (&JACKPortEngine::connected_to_jack, this));
-}
-
-JACKPortEngine::~JACKPortEngine ()
-{
-	/* a default destructor would do this, and so would this one,
-	   but we'll make it explicit in case we ever need to debug
-	   the lifetime of the JACKConnection
-	*/
-	_jack_connection.reset ();
-}
-
 void
-JACKPortEngine::connected_to_jack ()
+JACKAudioBackend::when_connected_to_jack ()
 {
 	/* register callbacks for stuff that is our responsibility */
 
@@ -119,57 +104,45 @@ JACKPortEngine::connected_to_jack ()
         jack_set_graph_order_callback (client, _graph_order_callback, this);
 }
 
-void*
-JACKPortEngine::private_handle() const
-{
-	return _jack_connection->jack();
-}
-
-bool
-JACKPortEngine::connected() const
-{
-	return _jack_connection->connected();
-}
-
 int
-JACKPortEngine::set_port_name (PortHandle port, const std::string& name)
+JACKAudioBackend::set_port_name (PortHandle port, const std::string& name)
 {
 	return jack_port_set_name ((jack_port_t*) port, name.c_str());
 }
 
 string
-JACKPortEngine::get_port_name (PortHandle port) const
+JACKAudioBackend::get_port_name (PortHandle port) const
 {
 	return jack_port_name ((jack_port_t*) port);
 }
 
 PortEngine::PortHandle*
-JACKPortEngine:: get_port_by_name (const std::string& name) const
+JACKAudioBackend:: get_port_by_name (const std::string& name) const
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, 0);
 	return (PortHandle*) jack_port_by_name (_priv_jack, name.c_str());
 }
 
 void
-JACKPortEngine::_registration_callback (jack_port_id_t /*id*/, int /*reg*/, void* arg)
+JACKAudioBackend::_registration_callback (jack_port_id_t /*id*/, int /*reg*/, void* arg)
 {
-	static_cast<JACKPortEngine*> (arg)->manager.registration_callback ();
+	static_cast<JACKAudioBackend*> (arg)->manager.registration_callback ();
 }
 
 int
-JACKPortEngine::_graph_order_callback (void *arg)
+JACKAudioBackend::_graph_order_callback (void *arg)
 {
-	return static_cast<JACKPortEngine*> (arg)->manager.graph_order_callback ();
+	return static_cast<JACKAudioBackend*> (arg)->manager.graph_order_callback ();
 }
 
 void
-JACKPortEngine::_connect_callback (jack_port_id_t id_a, jack_port_id_t id_b, int conn, void* arg)
+JACKAudioBackend::_connect_callback (jack_port_id_t id_a, jack_port_id_t id_b, int conn, void* arg)
 {
-	static_cast<JACKPortEngine*> (arg)->connect_callback (id_a, id_b, conn);
+	static_cast<JACKAudioBackend*> (arg)->connect_callback (id_a, id_b, conn);
 }
 
 void
-JACKPortEngine::connect_callback (jack_port_id_t id_a, jack_port_id_t id_b, int conn)
+JACKAudioBackend::connect_callback (jack_port_id_t id_a, jack_port_id_t id_b, int conn)
 {
 	if (manager.port_remove_in_progress()) {
 		return;
@@ -184,7 +157,7 @@ JACKPortEngine::connect_callback (jack_port_id_t id_a, jack_port_id_t id_b, int
 }
 
 bool
-JACKPortEngine::connected (PortHandle port, bool process_callback_safe)
+JACKAudioBackend::connected (PortHandle port, bool process_callback_safe)
 {
 	bool ret = false;
 
@@ -207,7 +180,7 @@ JACKPortEngine::connected (PortHandle port, bool process_callback_safe)
 }
 
 bool
-JACKPortEngine::connected_to (PortHandle port, const std::string& other, bool process_callback_safe)
+JACKAudioBackend::connected_to (PortHandle port, const std::string& other, bool process_callback_safe)
 {
 	bool ret = false;
 	const char** ports;
@@ -232,7 +205,7 @@ JACKPortEngine::connected_to (PortHandle port, const std::string& other, bool pr
 }
 
 bool
-JACKPortEngine::physically_connected (PortHandle p, bool process_callback_safe)
+JACKAudioBackend::physically_connected (PortHandle p, bool process_callback_safe)
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, false);
 	jack_port_t* port = (jack_port_t*) p;
@@ -262,7 +235,7 @@ JACKPortEngine::physically_connected (PortHandle p, bool process_callback_safe)
 }
 
 int
-JACKPortEngine::get_connections (PortHandle port, vector<string>& s, bool process_callback_safe)
+JACKAudioBackend::get_connections (PortHandle port, vector<string>& s, bool process_callback_safe)
 {
 	const char** ports;
 
@@ -284,19 +257,19 @@ JACKPortEngine::get_connections (PortHandle port, vector<string>& s, bool proces
 }
 
 DataType
-JACKPortEngine::port_data_type (PortHandle p) const
+JACKAudioBackend::port_data_type (PortHandle p) const
 {
 	return jack_port_type_to_ardour_data_type (jack_port_type ((jack_port_t*) p));
 }
 
 const string&
-JACKPortEngine::my_name() const
+JACKAudioBackend::my_name() const
 {
 	return _jack_connection->client_name();
 }
 
 bool
-JACKPortEngine::port_is_physical (PortHandle ph) const
+JACKAudioBackend::port_is_physical (PortHandle ph) const
 {
 	if (!ph) {
                 return false;
@@ -306,7 +279,7 @@ JACKPortEngine::port_is_physical (PortHandle ph) const
 }
 
 int
-JACKPortEngine::get_ports (const string& port_name_pattern, DataType type, PortFlags flags, vector<string>& s) const
+JACKAudioBackend::get_ports (const string& port_name_pattern, DataType type, PortFlags flags, vector<string>& s) const
 {
 
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack,0);
@@ -329,44 +302,19 @@ JACKPortEngine::get_ports (const string& port_name_pattern, DataType type, PortF
 }
 
 ChanCount
-JACKPortEngine::n_physical (unsigned long flags) const
-{
-	ChanCount c;
-
-	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, c);
-
-	const char ** ports = jack_get_ports (_priv_jack, NULL, NULL, JackPortIsPhysical | flags);
-
-	if (ports) {
-		for (uint32_t i = 0; ports[i]; ++i) {
-			if (!strstr (ports[i], "Midi-Through")) {
-				DataType t = port_data_type (jack_port_by_name (_priv_jack, ports[i]));
-				if (t != DataType::NIL) {
-					c.set (t, c.get (t) + 1);
-				}
-			}
-		}
-		
-		jack_free (ports);
-	}
-
-	return c;
-}
-
-ChanCount
-JACKPortEngine::n_physical_inputs () const
+JACKAudioBackend::n_physical_inputs () const
 {
 	return n_physical (JackPortIsInput);
 }
 
 ChanCount
-JACKPortEngine::n_physical_outputs () const
+JACKAudioBackend::n_physical_outputs () const
 {
 	return n_physical (JackPortIsOutput);
 }
 
 void
-JACKPortEngine::get_physical (DataType type, unsigned long flags, vector<string>& phy) const
+JACKAudioBackend::get_physical (DataType type, unsigned long flags, vector<string>& phy) const
 {
 	GET_PRIVATE_JACK_POINTER (_priv_jack);
 	const char ** ports;
@@ -390,7 +338,7 @@ JACKPortEngine::get_physical (DataType type, unsigned long flags, vector<string>
  *  a physical input connector.
  */
 void
-JACKPortEngine::get_physical_inputs (DataType type, vector<string>& ins)
+JACKAudioBackend::get_physical_inputs (DataType type, vector<string>& ins)
 {
 	get_physical (type, JackPortIsOutput, ins);
 }
@@ -399,14 +347,14 @@ JACKPortEngine::get_physical_inputs (DataType type, vector<string>& ins)
  *  a physical output connector.
  */
 void
-JACKPortEngine::get_physical_outputs (DataType type, vector<string>& outs)
+JACKAudioBackend::get_physical_outputs (DataType type, vector<string>& outs)
 {
 	get_physical (type, JackPortIsInput, outs);
 }
 
 
 bool
-JACKPortEngine::can_monitor_input () const
+JACKAudioBackend::can_monitor_input () const
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack,false);
 	const char ** ports;
@@ -421,32 +369,23 @@ JACKPortEngine::can_monitor_input () const
 }
 
 int
-JACKPortEngine::request_input_monitoring (PortHandle port, bool yn)
+JACKAudioBackend::request_input_monitoring (PortHandle port, bool yn)
 {
 	return jack_port_request_monitor ((jack_port_t*) port, yn);
 }
 int
-JACKPortEngine::ensure_input_monitoring (PortHandle port, bool yn)
+JACKAudioBackend::ensure_input_monitoring (PortHandle port, bool yn)
 {
 	return jack_port_ensure_monitor ((jack_port_t*) port, yn);
 }
 bool
-JACKPortEngine::monitoring_input (PortHandle port)
+JACKAudioBackend::monitoring_input (PortHandle port)
 {
 	return jack_port_monitoring_input ((jack_port_t*) port);
 }
 
-
-pframes_t
-JACKPortEngine::sample_time_at_cycle_start ()
-{
-	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, 0);
-	return jack_last_frame_time (_priv_jack);
-}
-
-
 PortEngine::PortHandle
-JACKPortEngine::register_port (const std::string& shortname, ARDOUR::DataType type, ARDOUR::PortFlags flags)
+JACKAudioBackend::register_port (const std::string& shortname, ARDOUR::DataType type, ARDOUR::PortFlags flags)
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, 0);
 	return jack_port_register (_priv_jack, shortname.c_str(), 
@@ -456,20 +395,20 @@ JACKPortEngine::register_port (const std::string& shortname, ARDOUR::DataType ty
 }
 
 void
-JACKPortEngine::unregister_port (PortHandle port)
+JACKAudioBackend::unregister_port (PortHandle port)
 {
 	GET_PRIVATE_JACK_POINTER (_priv_jack);
 	(void) jack_port_unregister (_priv_jack, (jack_port_t*) port);
 }
 
 int
-JACKPortEngine::connect (PortHandle port, const std::string& other)
+JACKAudioBackend::connect (PortHandle port, const std::string& other)
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, -1);
 	return jack_connect (_priv_jack, jack_port_name ((jack_port_t*) port), other.c_str());
 }
 int
-JACKPortEngine::connect (const std::string& src, const std::string& dst)
+JACKAudioBackend::connect (const std::string& src, const std::string& dst)
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, -1);
 	
@@ -478,28 +417,28 @@ JACKPortEngine::connect (const std::string& src, const std::string& dst)
 }
 
 int
-JACKPortEngine::disconnect (PortHandle port, const std::string& other)
+JACKAudioBackend::disconnect (PortHandle port, const std::string& other)
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, -1);
 	return jack_disconnect (_priv_jack, jack_port_name ((jack_port_t*) port), other.c_str());
 }
 
 int
-JACKPortEngine::disconnect (const std::string& src, const std::string& dst)
+JACKAudioBackend::disconnect (const std::string& src, const std::string& dst)
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, -1);
 	return jack_disconnect (_priv_jack, src.c_str(), dst.c_str());
 }
 
 int
-JACKPortEngine::disconnect_all (PortHandle port)
+JACKAudioBackend::disconnect_all (PortHandle port)
 {
 	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, -1);
 	return jack_port_disconnect (_priv_jack, (jack_port_t*) port);
 }
 
 int
-JACKPortEngine::midi_event_get (pframes_t& timestamp, size_t& size, uint8_t** buf, void* port_buffer, uint32_t event_index)
+JACKAudioBackend::midi_event_get (pframes_t& timestamp, size_t& size, uint8_t** buf, void* port_buffer, uint32_t event_index)
 {
 	jack_midi_event_t ev;
 	int ret;
@@ -514,25 +453,25 @@ JACKPortEngine::midi_event_get (pframes_t& timestamp, size_t& size, uint8_t** bu
 }
 
 int
-JACKPortEngine::midi_event_put (void* port_buffer, pframes_t timestamp, const uint8_t* buffer, size_t size)
+JACKAudioBackend::midi_event_put (void* port_buffer, pframes_t timestamp, const uint8_t* buffer, size_t size)
 {
 	return jack_midi_event_write (port_buffer, timestamp, buffer, size);
 }
 
 uint32_t
-JACKPortEngine::get_midi_event_count (void* port_buffer)
+JACKAudioBackend::get_midi_event_count (void* port_buffer)
 {
 	return jack_midi_get_event_count (port_buffer);
 }
 
 void
-JACKPortEngine::midi_clear (void* port_buffer)
+JACKAudioBackend::midi_clear (void* port_buffer)
 {
 	jack_midi_clear_buffer (port_buffer);
 }
 
 void
-JACKPortEngine::set_latency_range (PortHandle port, bool for_playback, LatencyRange r)
+JACKAudioBackend::set_latency_range (PortHandle port, bool for_playback, LatencyRange r)
 {
 	jack_latency_range_t range;
 	
@@ -543,7 +482,7 @@ JACKPortEngine::set_latency_range (PortHandle port, bool for_playback, LatencyRa
 }
 
 LatencyRange
-JACKPortEngine::get_latency_range (PortHandle port, bool for_playback)
+JACKAudioBackend::get_latency_range (PortHandle port, bool for_playback)
 {
 	jack_latency_range_t range;
 	LatencyRange ret;
@@ -557,13 +496,13 @@ JACKPortEngine::get_latency_range (PortHandle port, bool for_playback)
 }
 
 void*
-JACKPortEngine::get_buffer (PortHandle port, pframes_t nframes)
+JACKAudioBackend::get_buffer (PortHandle port, pframes_t nframes)
 {
 	return jack_port_get_buffer ((jack_port_t*) port, nframes);
 }
 
 uint32_t
-JACKPortEngine::port_name_size() const
+JACKAudioBackend::port_name_size() const
 {
 	return jack_port_name_size ();
 }
diff --git a/libs/backends/jack/jack_portengine.h b/libs/backends/jack/jack_portengine.h
deleted file mode 100644
index 0e1eb48c5c..0000000000
--- a/libs/backends/jack/jack_portengine.h
+++ /dev/null
@@ -1,132 +0,0 @@
-/*
-    Copyright (C) 2013 Paul Davis
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-
-*/
-
-#ifndef __libardour_jack_portengine_h__
-#define __libardour_jack_portengine_h__
-
-#include <string>
-#include <vector>
-
-#include <stdint.h>
-
-#include <jack/types.h>
-#include <jack/midiport.h>
-
-#include <boost/shared_ptr.hpp>
-
-#include "pbd/signals.h"
-
-#include "ardour/port_engine.h"
-#include "ardour/types.h"
-
-namespace ARDOUR {
-
-class JackConnection;
-
-class JACKPortEngine : public PortEngine 
-{
-  public:
-    JACKPortEngine (PortManager&, boost::shared_ptr<JackConnection>);
-    ~JACKPortEngine();
-
-    void* private_handle() const;
-    bool connected() const;
-
-    const std::string& my_name() const;
-
-    uint32_t port_name_size() const;
-
-    int         set_port_name (PortHandle, const std::string&);
-    std::string get_port_name (PortHandle) const;
-    PortHandle* get_port_by_name (const std::string&) const;
-
-    int get_ports (const std::string& port_name_pattern, DataType type, PortFlags flags, std::vector<std::string>&) const;
-
-    DataType port_data_type (PortHandle) const;
-
-    PortHandle register_port (const std::string& shortname, ARDOUR::DataType, ARDOUR::PortFlags);
-    void  unregister_port (PortHandle);
-
-    bool  connected (PortHandle, bool process_callback_safe);
-    bool  connected_to (PortHandle, const std::string&, bool process_callback_safe);
-    bool  physically_connected (PortHandle, bool process_callback_safe);
-    int   get_connections (PortHandle, std::vector<std::string>&, bool process_callback_safe);
-    int   connect (PortHandle, const std::string&);
-
-    int   disconnect (PortHandle, const std::string&);
-    int   disconnect_all (PortHandle);
-    int   connect (const std::string& src, const std::string& dst);
-    int   disconnect (const std::string& src, const std::string& dst);
-    
-    /* MIDI */
-
-    int      midi_event_get (pframes_t& timestamp, size_t& size, uint8_t** buf, void* port_buffer, uint32_t event_index);
-    int      midi_event_put (void* port_buffer, pframes_t timestamp, const uint8_t* buffer, size_t size);
-    uint32_t get_midi_event_count (void* port_buffer);
-    void     midi_clear (void* port_buffer);
-
-    /* Monitoring */
-
-    bool  can_monitor_input() const;
-    int   request_input_monitoring (PortHandle, bool);
-    int   ensure_input_monitoring (PortHandle, bool);
-    bool  monitoring_input (PortHandle);
-
-    /* Latency management
-     */
-    
-    void          set_latency_range (PortHandle, bool for_playback, LatencyRange);
-    LatencyRange  get_latency_range (PortHandle, bool for_playback);
-
-    /* Physical ports */
-
-    bool      port_is_physical (PortHandle) const;
-    void      get_physical_outputs (DataType type, std::vector<std::string>&);
-    void      get_physical_inputs (DataType type, std::vector<std::string>&);
-    ChanCount n_physical_outputs () const;
-    ChanCount n_physical_inputs () const;
-
-    /* Getting access to the data buffer for a port */
-
-    void* get_buffer (PortHandle, pframes_t);
-
-    /* Miscellany */
-
-    pframes_t sample_time_at_cycle_start ();
-    
-  private:
-    boost::shared_ptr<JackConnection> _jack_connection;
-
-    static int  _graph_order_callback (void *arg);
-    static void _registration_callback (jack_port_id_t, int, void *);
-    static void _connect_callback (jack_port_id_t, jack_port_id_t, int, void *);
-
-    void connect_callback (jack_port_id_t, jack_port_id_t, int);
-
-    ChanCount n_physical (unsigned long flags) const;
-    void get_physical (DataType type, unsigned long flags, std::vector<std::string>& phy) const;
-
-    PBD::ScopedConnection jack_connection_connection;
-    void connected_to_jack ();
-
-};
-
-} // namespace 
-
-#endif /* __libardour_jack_portengine_h__ */