prepare MIDI latency measurement (backend)

gtk2_ardour/engine_dialog.cc

@@ -1699,7 +1699,7 @@ EngineControl::start_latency_detection ()
 	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());
 
-	if (ARDOUR::AudioEngine::instance()->start_latency_detection () == 0) {
+	if (ARDOUR::AudioEngine::instance()->start_latency_detection (false) == 0) {
 		lm_results.set_markup (string_compose (results_markup, _("Detecting ...")));
 		latency_timeout = Glib::signal_timeout().connect (mem_fun (*this, &EngineControl::check_latency_measurement), 100);
 		lm_measure_label.set_text (_("Cancel"));

libs/ardour/ardour/audioengine.h

@@ -54,6 +54,7 @@ namespace ARDOUR {
 
 class InternalPort;
 class MidiPort;
+class MIDIDM;
 class Port;
 class Session;
 class ProcessThread;
@@ -191,14 +192,24 @@ public:
 
     /* latency measurement */
 
-    MTDM* mtdm();
+    MTDM* mtdm() { return _mtdm; }
+    MIDIDM* mididm() { return _mididm; }
+
     int  prepare_for_latency_measurement ();
-    int  start_latency_detection ();
+    int  start_latency_detection (bool);
     void stop_latency_detection ();
     void set_latency_input_port (const std::string&);
     void set_latency_output_port (const std::string&);
     uint32_t latency_signal_delay () const { return _latency_signal_latency; }
 
+		enum LatencyMeasurement {
+			MeasureNone,
+			MeasureAudio,
+			MeasureMIDI
+		};
+
+		LatencyMeasurement measuring_latency () const { return _measuring_latency; }
+
   private:
     AudioEngine ();
 
@@ -221,7 +232,8 @@ public:
     Glib::Threads::Thread*     m_meter_thread;
     ProcessThread*            _main_thread;
     MTDM*                     _mtdm;
-    bool                      _measuring_latency;
+    MIDIDM*                   _mididm;
+		LatencyMeasurement        _measuring_latency;
     PortEngine::PortHandle    _latency_input_port;
     PortEngine::PortHandle    _latency_output_port;
     framecnt_t                _latency_flush_frames;

libs/ardour/ardour/mididm.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2013-2014 Robin Gareus <robin@gareus.org>
+ *
+ * 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_mididm_h__
+#define __libardour_mididm_h__
+
+#include "ardour/types.h"
+#include "ardour/libardour_visibility.h"
+
+namespace ARDOUR {
+
+class PortEngine;
+
+class LIBARDOUR_API MIDIDM
+{
+public:
+
+	MIDIDM (framecnt_t sample_rate);
+
+	int process (pframes_t nframes, PortEngine &pe, void *midi_in, void *midi_out);
+
+	framecnt_t latency (void) { return _cnt_total > 10 ? _avg_delay : 0; }
+	framecnt_t processed (void) { return _cnt_total; }
+	double     deviation (void) { return _cnt_total > 1 ? sqrt(_var_s / ((double)(_cnt_total - 1))) : 0; }
+	bool       ok (void) { return _cnt_total > 200; }
+	bool       have_signal (void) { return (_monotonic_cnt - _last_signal_tme) < (uint64_t) _sample_rate ; }
+
+private:
+
+	framecnt_t _sample_rate;
+
+	uint64_t _monotonic_cnt;
+	uint64_t _last_signal_tme;
+
+	uint64_t _cnt_total;
+	uint64_t _dly_total;
+	uint32_t _min_delay;
+	uint32_t _max_delay;
+	double   _avg_delay;
+	double   _var_m;
+	double   _var_s;
+
+};
+
+}
+
+#endif /* __libardour_mididm_h__ */

libs/ardour/audioengine.cc

@@ -48,6 +48,7 @@
 #include "ardour/meter.h"
 #include "ardour/midi_port.h"
 #include "ardour/midiport_manager.h"
+#include "ardour/mididm.h"
 #include "ardour/mtdm.h"
 #include "ardour/port.h"
 #include "ardour/process_thread.h"
@@ -73,7 +74,8 @@ AudioEngine::AudioEngine ()
 	, m_meter_thread (0)
 	, _main_thread (0)
 	, _mtdm (0)
-	, _measuring_latency (false)
+	, _mididm (0)
+	, _measuring_latency (MeasureNone)
 	, _latency_input_port (0)
 	, _latency_output_port (0)
 	, _latency_flush_frames (0)
@@ -195,7 +197,7 @@ AudioEngine::process_callback (pframes_t nframes)
 
 	bool return_after_remove_check = false;
 
-	if (_measuring_latency && _mtdm) {
+	if (_measuring_latency == MeasureAudio && _mtdm) {
 		/* run a normal cycle from the perspective of the PortManager
 		   so that we get silence on all registered ports.
 		   
@@ -218,6 +220,28 @@ AudioEngine::process_callback (pframes_t nframes)
 		PortManager::cycle_end (nframes);
 		return_after_remove_check = true;
 
+	} else if (_measuring_latency == MeasureMIDI && _mididm) {
+		/* 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);
+
+		if (_latency_input_port && _latency_output_port) {
+			PortEngine& pe (port_engine());
+
+			_mididm->process (nframes, pe,
+					pe.get_buffer (_latency_input_port, nframes),
+					pe.get_buffer (_latency_output_port, nframes));
+		}
+
+		PortManager::cycle_end (nframes);
+		return_after_remove_check = true;
+
 	} else if (_latency_flush_frames) {
 		
 		/* wait for the appropriate duration for the MTDM signal to
@@ -660,7 +684,7 @@ AudioEngine::stop (bool for_latency)
 	
 	_running = false;
 	_processed_frames = 0;
-	_measuring_latency = false;
+	_measuring_latency = MeasureNone;
 	_latency_output_port = 0;
 	_latency_input_port = 0;
 	_started_for_latency = false;
@@ -1029,12 +1053,6 @@ AudioEngine::setup_required () const
 	return true;
 }
 
-MTDM*
-AudioEngine::mtdm() 
-{
-	return _mtdm;
-}
-
 int
 AudioEngine::prepare_for_latency_measurement ()
 {
@@ -1052,7 +1070,7 @@ AudioEngine::prepare_for_latency_measurement ()
 }
 
 int
-AudioEngine::start_latency_detection ()
+AudioEngine::start_latency_detection (bool for_midi)
 {
 	if (!running()) {
 		if (prepare_for_latency_measurement ()) {
@@ -1065,6 +1083,9 @@ AudioEngine::start_latency_detection ()
 	delete _mtdm;
 	_mtdm = 0;
 
+	delete _mididm;
+	_mididm = 0;
+
 	/* find the ports we will connect to */
 
 	PortEngine::PortHandle out = pe.get_port_by_name (_latency_output_name);
@@ -1076,27 +1097,57 @@ AudioEngine::start_latency_detection ()
 	}
 
 	/* create the ports we will use to read/write data */
-	
-	if ((_latency_output_port = pe.register_port ("latency_out", DataType::AUDIO, IsOutput)) == 0) {
-		stop (true);
-		return -1;
-	}
-	if (pe.connect (_latency_output_port, _latency_output_name)) {
-		pe.unregister_port (_latency_output_port);
-		stop (true);
-		return -1;
-	}
+	if (for_midi) {
+		if ((_latency_output_port = pe.register_port ("latency_out", DataType::MIDI, IsOutput)) == 0) {
+			stop (true);
+			return -1;
+		}
+		if (pe.connect (_latency_output_port, _latency_output_name)) {
+			pe.unregister_port (_latency_output_port);
+			stop (true);
+			return -1;
+		}
+
+		const string portname ("latency_in");
+		if ((_latency_input_port = pe.register_port (portname, DataType::MIDI, IsInput)) == 0) {
+			pe.unregister_port (_latency_output_port);
+			stop (true);
+			return -1;
+		}
+		if (pe.connect (_latency_input_name, make_port_name_non_relative (portname))) {
+			pe.unregister_port (_latency_output_port);
+			stop (true);
+			return -1;
+		}
+
+		_mididm = new MIDIDM (sample_rate());
+
+	} else {
+
+		if ((_latency_output_port = pe.register_port ("latency_out", DataType::AUDIO, IsOutput)) == 0) {
+			stop (true);
+			return -1;
+		}
+		if (pe.connect (_latency_output_port, _latency_output_name)) {
+			pe.unregister_port (_latency_output_port);
+			stop (true);
+			return -1;
+		}
+
+		const string portname ("latency_in");
+		if ((_latency_input_port = pe.register_port (portname, DataType::AUDIO, IsInput)) == 0) {
+			pe.unregister_port (_latency_output_port);
+			stop (true);
+			return -1;
+		}
+		if (pe.connect (_latency_input_name, make_port_name_non_relative (portname))) {
+			pe.unregister_port (_latency_output_port);
+			stop (true);
+			return -1;
+		}
+
+		_mtdm = new MTDM (sample_rate());
 
-	const string portname ("latency_in");
-	if ((_latency_input_port = pe.register_port (portname, DataType::AUDIO, IsInput)) == 0) {
-		pe.unregister_port (_latency_output_port);
-		stop (true);
-		return -1;
-	}
-	if (pe.connect (_latency_input_name, make_port_name_non_relative (portname))) {
-		pe.unregister_port (_latency_output_port);
-		stop (true);
-		return -1;
 	}
 
 	LatencyRange lr;
@@ -1107,10 +1158,8 @@ AudioEngine::start_latency_detection ()
 	_latency_signal_latency += lr.max;
 
 	/* all created and connected, lets go */
-
-	_mtdm = new MTDM (sample_rate());
-	_measuring_latency = true;
-        _latency_flush_frames = samples_per_cycle();
+	_latency_flush_frames = samples_per_cycle();
+	_measuring_latency = for_midi ? MeasureMIDI : MeasureAudio;
 
 	return 0;
 }
@@ -1118,7 +1167,7 @@ AudioEngine::start_latency_detection ()
 void
 AudioEngine::stop_latency_detection ()
 {
-	_measuring_latency = false;
+	_measuring_latency = MeasureNone;
 
 	if (_latency_output_port) {
 		port_engine().unregister_port (_latency_output_port);

libs/ardour/mididm.cc

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2013-2014 Robin Gareus <robin@gareus.org>
+ *
+ * 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.
+ */
+
+#include "ardour/mididm.h"
+#include "ardour/port_engine.h"
+
+using namespace ARDOUR;
+
+MIDIDM::MIDIDM (framecnt_t sample_rate)
+  : _sample_rate (sample_rate)
+  , _monotonic_cnt (sample_rate)
+  , _last_signal_tme (0)
+  , _cnt_total (0)
+  , _dly_total (0)
+  , _min_delay (INT32_MAX)
+  , _max_delay (0)
+  , _avg_delay (0)
+  , _var_m (0)
+  , _var_s (0)
+{
+
+}
+
+
+int MIDIDM::process (pframes_t nframes, PortEngine &pe, void *midi_in, void *midi_out)
+{
+	/* send midi event */
+	uint8_t obuf[3];
+	obuf[0] = 0xf2;
+	obuf[1] = (_monotonic_cnt)      & 0x7f;
+	obuf[2] = (_monotonic_cnt >> 7) & 0x7f;
+
+	pe.midi_clear(midi_out);
+	pe.midi_event_put (midi_out, 0, obuf, 3);
+
+	/* process incoming */
+	const pframes_t nevents = pe.get_midi_event_count (midi_in);
+	for (pframes_t n = 0; n < nevents; ++n) {
+		pframes_t timestamp;
+		size_t size;
+		uint8_t* buf;
+		pe.midi_event_get (timestamp, size, &buf, midi_in, n);
+
+		if (size != 3 || buf[0] != 0xf2 ) continue;
+
+		_last_signal_tme = _monotonic_cnt;
+
+		/* calculate time difference */
+#define MODX (16384)  // 1<<(2*7)
+#define MASK (0x3fff) // MODX - 1
+		const int64_t tc = (_monotonic_cnt + timestamp) & MASK;
+		const int64_t ti = (buf[2] << 7) | buf[1];
+		const int64_t tdiff = (MODX + tc - ti) % MODX;
+
+		/* running variance */
+		if (_cnt_total == 0) {
+			_var_m = tdiff;
+		} else {
+			const double var_m1 = _var_m;
+			_var_m = _var_m + ((double)tdiff - _var_m) / (double)(_cnt_total + 1);
+			_var_s = _var_s + ((double)tdiff - _var_m) * ((double)tdiff - var_m1);
+		}
+		/* average and mix/max */
+		++_cnt_total;
+		_dly_total += tdiff;
+		_avg_delay = _dly_total / _cnt_total;
+		if (tdiff < _min_delay) _min_delay = tdiff;
+		if (tdiff > _max_delay) _max_delay = tdiff;
+	}
+
+  _monotonic_cnt += nframes;
+	return 0;
+}

libs/ardour/wscript

@@ -130,6 +130,7 @@ libardour_sources = [
         'mix.cc',
         'monitor_processor.cc',
         'mtc_slave.cc',
+        'mididm.cc',
         'mtdm.cc',
         'mute_master.cc',
         'onset_detector.cc',