WinMME based midi input/output for portaudio backend

TODO:

Use MMCSS to elevate thread priorities
Enable/test and fix SYSEX related code

18 files changed, 2074 insertions, 72 deletions

diff --git a/libs/backends/portaudio/cycle_timer.h b/libs/backends/portaudio/cycle_timer.h
new file mode 100644
index 0000000000..95811ae1ca
--- /dev/null
+++ b/libs/backends/portaudio/cycle_timer.h
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 CYCLE_TIMER_H
+#define CYCLE_TIMER_H
+
+#include <stdint.h>
+#include <cmath>
+#include <algorithm>
+
+// Could call it FrameTimer and make it more generic
+// Could be an interface and or include clock source
+// include sample count/processed frames in iteration?
+class CycleTimer {
+public:
+	CycleTimer ()
+	    : m_cycle_start (0)
+	    , m_samplerate (0)
+	    , m_samples_per_cycle (0)
+	{
+	}
+
+	void set_samplerate (double samplerate) { m_samplerate = samplerate; }
+
+	double get_samplerate () const { return m_samplerate; }
+
+	double get_sample_length_us () const { return 1e6 / m_samplerate; }
+
+	double get_length_us () const
+	{
+		return get_sample_length_us () * m_samples_per_cycle;
+	}
+
+	void set_samples_per_cycle (uint32_t samples)
+	{
+		m_samples_per_cycle = samples;
+	}
+
+	uint32_t get_samples_per_cycle () const { return m_samples_per_cycle; }
+
+	// rint?? that may round to sample outside of cycle?
+	// max(0, value)?
+	uint32_t samples_since_cycle_start (uint64_t timer_val) const
+	{
+		if (timer_val < m_cycle_start) {
+			return 0;
+		}
+		return std::max((double)0, (timer_val - get_start ()) / get_sample_length_us ());
+	}
+
+	uint64_t timestamp_from_sample_offset (uint32_t sample_offset)
+	{
+		return m_cycle_start + get_sample_length_us () * sample_offset;
+	}
+
+	bool valid () const { return m_samples_per_cycle && m_samplerate; }
+
+	bool in_cycle (uint64_t timer_value_us) const
+	{ return (timer_value_us >= get_start()) && (timer_value_us < get_next_start());
+	}
+
+	void reset_start (uint64_t timestamp) { m_cycle_start = timestamp; }
+
+	uint64_t get_start () const { return m_cycle_start; }
+
+	uint64_t microseconds_since_start (uint64_t timestamp) const
+	{
+		return timestamp - m_cycle_start;
+	}
+
+	uint64_t microseconds_since_start (uint32_t samples) const
+	{
+		return m_cycle_start + samples * get_sample_length_us ();
+	}
+
+	uint64_t get_next_start () const
+	{
+		return m_cycle_start + rint (get_length_us ());
+	}
+
+private:
+	uint64_t m_cycle_start;
+
+	uint32_t m_samplerate;
+	uint32_t m_samples_per_cycle;
+};
+
+#endif // CYCLE_TIMER_H
diff --git a/libs/backends/portaudio/debug.h b/libs/backends/portaudio/debug.h
new file mode 100644
index 0000000000..0270efa2a6
--- /dev/null
+++ b/libs/backends/portaudio/debug.h
@@ -0,0 +1,13 @@
+#ifndef PORTAUDIO_BACKEND_DEBUG_H
+#define PORTAUDIO_BACKEND_DEBUG_H
+
+#include "pbd/debug.h"
+
+using namespace PBD;
+
+#define DEBUG_AUDIO(msg) DEBUG_TRACE (DEBUG::BackendAudio, msg);
+#define DEBUG_MIDI(msg) DEBUG_TRACE (DEBUG::BackendMIDI, msg);
+#define DEBUG_TIMING(msg) DEBUG_TRACE (DEBUG::BackendTiming, msg);
+#define DEBUG_THREADS(msg) DEBUG_TRACE (DEBUG::BackendThreads, msg);
+
+#endif // PORTAUDIO_BACKEND_DEBUG_H
diff --git a/libs/backends/portaudio/midi_util.cc b/libs/backends/portaudio/midi_util.cc
new file mode 100644
index 0000000000..0542dfc5b2
--- /dev/null
+++ b/libs/backends/portaudio/midi_util.cc
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 "midi_util.h"
+
+int get_midi_msg_length (uint8_t status_byte)
+{
+	// define these with meaningful names
+	switch (status_byte & 0xf0) {
+	case 0x80:
+	case 0x90:
+	case 0xa0:
+	case 0xb0:
+	case 0xe0:
+		return 3;
+	case 0xc0:
+	case 0xd0:
+		return 2;
+	case 0xf0:
+		switch (status_byte) {
+		case 0xf0:
+			return 0;
+		case 0xf1:
+		case 0xf3:
+			return 2;
+		case 0xf2:
+			return 3;
+		case 0xf4:
+		case 0xf5:
+		case 0xf7:
+		case 0xfd:
+			break;
+		default:
+			return 1;
+		}
+	}
+	return -1;
+}
diff --git a/libs/backends/portaudio/midi_util.h b/libs/backends/portaudio/midi_util.h
new file mode 100644
index 0000000000..7b6366a82e
--- /dev/null
+++ b/libs/backends/portaudio/midi_util.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 MIDI_UTIL_H
+#define MIDI_UTIL_H
+
+#include <stdint.h>
+
+struct MidiEventHeader {
+	uint64_t time;
+	size_t size;
+	MidiEventHeader (const uint64_t t, const size_t s)
+	    : time (t)
+	    , size (s)
+	{
+	}
+};
+
+// rename to get_midi_message_size?
+// @return -1 to indicate error
+int get_midi_msg_length (uint8_t status_byte);
+
+#endif
diff --git a/libs/backends/portaudio/portaudio_backend.cc b/libs/backends/portaudio/portaudio_backend.cc
index 71986cd376..a1fa2c96d1 100644
--- a/libs/backends/portaudio/portaudio_backend.cc
+++ b/libs/backends/portaudio/portaudio_backend.cc
@@ -36,8 +36,17 @@
 #include "ardour/port_manager.h"
 #include "i18n.h"
 
+#include "win_utils.h"
+#include "debug.h"
+
 using namespace ARDOUR;
 
+namespace {
+
+const char * const winmme_driver_name = X_("WinMME");
+
+}
+
 static std::string s_instance_name;
 size_t PortAudioBackend::_max_buffer_size = 8192;
 std::vector<std::string> PortAudioBackend::_midi_options;
@@ -51,7 +60,9 @@ PortAudioBackend::PortAudioBackend (AudioEngine& e, AudioBackendInfo& info)
 	, _active (false)
 	, _freewheel (false)
 	, _measure_latency (false)
-	, _last_process_start (0)
+	, m_cycle_count(0)
+	, m_total_deviation_us(0)
+	, m_max_deviation_us(0)
 	, _input_audio_device("")
 	, _output_audio_device("")
 	, _midi_driver_option(_("None"))
@@ -69,11 +80,13 @@ PortAudioBackend::PortAudioBackend (AudioEngine& e, AudioBackendInfo& info)
 	pthread_mutex_init (&_port_callback_mutex, 0);
 
 	_pcmio = new PortAudioIO ();
+	_midiio = new WinMMEMidiIO ();
 }
 
 PortAudioBackend::~PortAudioBackend ()
 {
 	delete _pcmio; _pcmio = 0;
+	delete _midiio; _midiio = 0;
 	pthread_mutex_destroy (&_port_callback_mutex);
 }
 
@@ -343,7 +356,7 @@ std::vector<std::string>
 PortAudioBackend::enumerate_midi_options () const
 {
 	if (_midi_options.empty()) {
-		//_midi_options.push_back (_("PortMidi"));
+		_midi_options.push_back (winmme_driver_name);
 		_midi_options.push_back (_("None"));
 	}
 	return _midi_options;
@@ -352,9 +365,10 @@ PortAudioBackend::enumerate_midi_options () const
 int
 PortAudioBackend::set_midi_option (const std::string& opt)
 {
-	if (opt != _("None") /* && opt != _("PortMidi")*/) {
+	if (opt != _("None") && opt != winmme_driver_name) {
 		return -1;
 	}
+	DEBUG_MIDI (string_compose ("Setting midi option to %1\n", opt));
 	_midi_driver_option = opt;
 	return 0;
 }
@@ -401,7 +415,6 @@ PortAudioBackend::_start (bool for_latency_measurement)
 	_dsp_load = 0;
 	_freewheeling = false;
 	_freewheel = false;
-	_last_process_start = 0;
 
 	_pcmio->pcm_setup (name_to_id(_input_audio_device), name_to_id(_output_audio_device), _samplerate, _samples_per_period);
 
@@ -441,10 +454,28 @@ PortAudioBackend::_start (bool for_latency_measurement)
 	_run = true;
 	_port_change_flag = false;
 
-	// TODO MIDI
+	if (_midi_driver_option == winmme_driver_name) {
+		_midiio->set_enabled(true);
+		//_midiio->set_port_changed_callback(midi_port_change, this);
+		_midiio->start(); // triggers port discovery, callback coremidi_rediscover()
+	}
+
+	m_cycle_timer.set_samplerate(_samplerate);
+	m_cycle_timer.set_samples_per_cycle(_samples_per_period);
+
+	DEBUG_MIDI ("Registering MIDI ports\n");
+
+	if (register_system_midi_ports () != 0) {
+		PBD::error << _ ("PortAudioBackend: failed to register system midi ports.")
+		           << endmsg;
+		_run = false;
+		return -1;
+	}
+
+	DEBUG_AUDIO ("Registering Audio ports\n");
 
 	if (register_system_audio_ports()) {
-		PBD::error << _("PortAudioBackend: failed to register system ports.") << endmsg;
+		PBD::error << _("PortAudioBackend: failed to register system audio ports.") << endmsg;
 		_run = false;
 		return -1;
 	}
@@ -557,12 +588,11 @@ PortAudioBackend::samples_since_cycle_start ()
 	if (!_active || !_run || _freewheeling || _freewheel) {
 		return 0;
 	}
-	if (_last_process_start == 0) {
+	if (!m_cycle_timer.valid()) {
 		return 0;
 	}
 
-	const int64_t elapsed_time_us = g_get_monotonic_time() - _last_process_start;
-	return std::max((pframes_t)0, (pframes_t)rint(1e-6 * elapsed_time_us * _samplerate));
+	return m_cycle_timer.samples_since_cycle_start (utils::get_microseconds());
 }
 
 int
@@ -846,6 +876,52 @@ PortAudioBackend::register_system_audio_ports()
 	return 0;
 }
 
+int
+PortAudioBackend::register_system_midi_ports()
+{
+	if (_midi_driver_option == _("None")) {
+		DEBUG_MIDI ("No MIDI backend selected, not system midi ports available\n");
+		return 0;
+	}
+
+	LatencyRange lr;
+	lr.min = lr.max = _samples_per_period;
+
+	const std::vector<WinMMEMidiInputDevice*> inputs = _midiio->get_inputs();
+
+	for (std::vector<WinMMEMidiInputDevice*>::const_iterator i = inputs.begin ();
+	     i != inputs.end ();
+	     ++i) {
+		std::string port_name = "system_midi:" + (*i)->name() + " capture";
+		PortHandle p =
+		    add_port (port_name,
+		              DataType::MIDI,
+		              static_cast<PortFlags>(IsOutput | IsPhysical | IsTerminal));
+		if (!p) return -1;
+		set_latency_range (p, false, lr);
+		_system_midi_in.push_back (static_cast<PortMidiPort*>(p));
+		DEBUG_MIDI (string_compose ("Registered MIDI input port: %1\n", port_name));
+	}
+
+	const std::vector<WinMMEMidiOutputDevice*> outputs = _midiio->get_outputs();
+
+	for (std::vector<WinMMEMidiOutputDevice*>::const_iterator i = outputs.begin ();
+	     i != outputs.end ();
+	     ++i) {
+		std::string port_name = "system_midi:" + (*i)->name() + " playback";
+		PortHandle p =
+		    add_port (port_name,
+		              DataType::MIDI,
+		              static_cast<PortFlags>(IsInput | IsPhysical | IsTerminal));
+		if (!p) return -1;
+		set_latency_range (p, false, lr);
+		static_cast<PortMidiPort*>(p)->set_n_periods(2);
+		_system_midi_out.push_back (static_cast<PortMidiPort*>(p));
+		DEBUG_MIDI (string_compose ("Registered MIDI output port: %1\n", port_name));
+	}
+	return 0;
+}
+
 void
 PortAudioBackend::unregister_ports (bool system_only)
 {
@@ -1015,11 +1091,10 @@ PortAudioBackend::midi_event_put (
 	if (!buffer || !port_buffer) return -1;
 	PortMidiBuffer& dst = * static_cast<PortMidiBuffer*>(port_buffer);
 	if (dst.size () && (pframes_t)dst.back ()->timestamp () > timestamp) {
-#ifndef NDEBUG
 		// nevermind, ::get_buffer() sorts events
-		fprintf (stderr, "PortMidiBuffer: unordered event: %d > %d\n",
-				(pframes_t)dst.back ()->timestamp (), timestamp);
-#endif
+		DEBUG_MIDI (string_compose ("PortMidiBuffer: unordered event: %1 > %2\n",
+		                            (pframes_t)dst.back ()->timestamp (),
+		                            timestamp));
 	}
 	dst.push_back (boost::shared_ptr<PortMidiEvent>(new PortMidiEvent (timestamp, buffer, size)));
 	return 0;
@@ -1200,7 +1275,10 @@ PortAudioBackend::main_process_thread ()
 	_processed_samples = 0;
 
 	uint64_t clock1, clock2;
+	int64_t min_elapsed_us = 1000000;
+	int64_t max_elapsed_us = 0;
 	const int64_t nomial_time = 1e6 * _samples_per_period / _samplerate;
+	// const int64_t nomial_time = m_cycle_timer.get_length_us();
 
 	manager.registration_callback();
 	manager.graph_order_callback();
@@ -1224,9 +1302,7 @@ PortAudioBackend::main_process_thread ()
 				case 0: // OK
 					break;
 				case 1:
-#ifndef NDEBUG
-					printf("PortAudio: Xrun\n");
-#endif
+					DEBUG_AUDIO ("PortAudio: Xrun\n");
 					engine.Xrun ();
 					break;
 				default:
@@ -1235,7 +1311,7 @@ PortAudioBackend::main_process_thread ()
 			}
 
 			uint32_t i = 0;
-			clock1 = g_get_monotonic_time();
+			clock1 = utils::get_microseconds ();
 
 			/* get audio */
 			i = 0;
@@ -1248,6 +1324,26 @@ PortAudioBackend::main_process_thread ()
 			for (std::vector<PamPort*>::const_iterator it = _system_midi_in.begin (); it != _system_midi_in.end (); ++it, ++i) {
 				PortMidiBuffer* mbuf = static_cast<PortMidiBuffer*>((*it)->get_buffer(0));
 				mbuf->clear();
+				uint64_t timestamp;
+				pframes_t sample_offset;
+				uint8_t data[256];
+				size_t size = sizeof(data);
+				while (_midiio->dequeue_input_event (i,
+				                                     m_cycle_timer.get_start (),
+				                                     m_cycle_timer.get_next_start (),
+				                                     timestamp,
+				                                     data,
+				                                     size)) {
+					sample_offset = m_cycle_timer.samples_since_cycle_start (timestamp);
+					midi_event_put (mbuf, sample_offset, data, size);
+					DEBUG_MIDI (string_compose ("Dequeuing incoming MIDI data for device: %1 "
+					                            "sample_offset: %2 timestamp: %3, size: %4\n",
+					                            _midiio->get_inputs ()[i]->name (),
+					                            sample_offset,
+					                            timestamp,
+					                            size));
+					size = sizeof(data);
+				}
 			}
 
 			/* clear output buffers */
@@ -1255,25 +1351,61 @@ PortAudioBackend::main_process_thread ()
 				memset ((*it)->get_buffer (_samples_per_period), 0, _samples_per_period * sizeof (Sample));
 			}
 
+			m_last_cycle_start = m_cycle_timer.get_start ();
+			m_cycle_timer.reset_start(utils::get_microseconds());
+			m_cycle_count++;
+
+			uint64_t cycle_diff_us = (m_cycle_timer.get_start () - m_last_cycle_start);
+			int64_t deviation_us = (cycle_diff_us - m_cycle_timer.get_length_us());
+			m_total_deviation_us += std::abs(deviation_us);
+			m_max_deviation_us =
+			    std::max (m_max_deviation_us, (uint64_t)std::abs (deviation_us));
+
+			if ((m_cycle_count % 1000) == 0) {
+				uint64_t mean_deviation_us = m_total_deviation_us / m_cycle_count;
+				DEBUG_TIMING (
+				    string_compose ("Mean avg cycle deviation: %1(ms), max %2(ms)\n",
+				                    mean_deviation_us * 1e-3,
+				                    m_max_deviation_us * 1e-3));
+			}
+
+			if (std::abs(deviation_us) > m_cycle_timer.get_length_us()) {
+				DEBUG_TIMING (string_compose (
+				    "time between process(ms): %1, Est(ms): %2, Dev(ms): %3\n",
+				    cycle_diff_us * 1e-3,
+				    m_cycle_timer.get_length_us () * 1e-3,
+				    deviation_us * 1e-3));
+			}
+
 			/* call engine process callback */
-			_last_process_start = g_get_monotonic_time();
 			if (engine.process_callback (_samples_per_period)) {
 				_pcmio->pcm_stop ();
 				_active = false;
 				return 0;
 			}
-#if 0
 			/* mixdown midi */
 			for (std::vector<PamPort*>::iterator it = _system_midi_out.begin (); it != _system_midi_out.end (); ++it) {
-				static_cast<PortBackendMidiPort*>(*it)->next_period();
+				static_cast<PortMidiPort*>(*it)->next_period();
 			}
-
 			/* queue outgoing midi */
 			i = 0;
 			for (std::vector<PamPort*>::const_iterator it = _system_midi_out.begin (); it != _system_midi_out.end (); ++it, ++i) {
-				// TODO
+				const PortMidiBuffer* src = static_cast<const PortMidiPort*>(*it)->const_buffer();
+
+				for (PortMidiBuffer::const_iterator mit = src->begin (); mit != src->end (); ++mit) {
+					uint64_t timestamp =
+					    m_cycle_timer.timestamp_from_sample_offset ((*mit)->timestamp ());
+					DEBUG_MIDI (
+					    string_compose ("Queuing outgoing MIDI data for device: "
+					                    "%1 sample_offset: %2 timestamp: %3, size: %4\n",
+					                    _midiio->get_outputs ()[i]->name (),
+					                    (*mit)->timestamp (),
+					                    timestamp,
+					                    (*mit)->size ()));
+					_midiio->enqueue_output_event (
+					    i, timestamp, (*mit)->data (), (*mit)->size ());
+				}
 			}
-#endif
 
 			/* write back audio */
 			i = 0;
@@ -1284,10 +1416,19 @@ PortAudioBackend::main_process_thread ()
 			_processed_samples += _samples_per_period;
 
 			/* calculate DSP load */
-			clock2 = g_get_monotonic_time();
+			clock2 = utils::get_microseconds ();
 			const int64_t elapsed_time = clock2 - clock1;
 			_dsp_load = elapsed_time / (float) nomial_time;
 
+			max_elapsed_us = std::max (elapsed_time, max_elapsed_us);
+			min_elapsed_us = std::min (elapsed_time, min_elapsed_us);
+			if ((m_cycle_count % 1000) == 0) {
+				DEBUG_TIMING (
+				    string_compose ("Elapsed process time(usecs) max: %1, min: %2\n",
+				                    max_elapsed_us,
+				                    min_elapsed_us));
+			}
+
 		} else {
 			// Freewheelin'
 
@@ -1296,11 +1437,10 @@ PortAudioBackend::main_process_thread ()
 				memset ((*it)->get_buffer (_samples_per_period), 0, _samples_per_period * sizeof (Sample));
 			}
 
-			clock1 = g_get_monotonic_time();
+			clock1 = utils::get_microseconds ();
 
 			// TODO clear midi or stop midi recv when entering fwheelin'
 
-			_last_process_start = 0;
 			if (engine.process_callback (_samples_per_period)) {
 				_pcmio->pcm_stop ();
 				_active = false;
diff --git a/libs/backends/portaudio/portaudio_backend.h b/libs/backends/portaudio/portaudio_backend.h
index d3def25fb1..9831d035d2 100644
--- a/libs/backends/portaudio/portaudio_backend.h
+++ b/libs/backends/portaudio/portaudio_backend.h
@@ -33,6 +33,8 @@
 #include "ardour/types.h"
 
 #include "portaudio_io.h"
+#include "winmmemidi_io.h"
+#include "cycle_timer.h"
 
 namespace ARDOUR {
 
@@ -312,6 +314,7 @@ class PortAudioBackend : public AudioBackend {
 	private:
 		std::string _instance_name;
 		PortAudioIO *_pcmio;
+		WinMMEMidiIO *_midiio;
 
 		bool  _run; /* keep going or stop, ardour thread */
 		bool  _active; /* is running, process thread */
@@ -319,7 +322,12 @@ class PortAudioBackend : public AudioBackend {
 		bool  _freewheeling;
 		bool  _measure_latency;
 
-		uint64_t _last_process_start;
+		uint64_t m_cycle_count;
+		uint64_t m_total_deviation_us;
+		uint64_t m_max_deviation_us;
+
+		CycleTimer m_cycle_timer;
+		uint64_t m_last_cycle_start;
 
 		static std::vector<std::string> _midi_options;
 		static std::vector<AudioBackend::DeviceStatus> _input_audio_device_status;
@@ -365,6 +373,7 @@ class PortAudioBackend : public AudioBackend {
 		/* port engine */
 		PortHandle add_port (const std::string& shortname, ARDOUR::DataType, ARDOUR::PortFlags);
 		int register_system_audio_ports ();
+		int register_system_midi_ports ();
 		void unregister_ports (bool system_only = false);
 
 		std::vector<PamPort *> _ports;
diff --git a/libs/backends/portaudio/portaudio_io.cc b/libs/backends/portaudio/portaudio_io.cc
index b7ea02ff22..4f967b370c 100644
--- a/libs/backends/portaudio/portaudio_io.cc
+++ b/libs/backends/portaudio/portaudio_io.cc
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2015 Robin Gareus <robin@gareus.org>
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
  *
  * 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
@@ -23,6 +24,10 @@
 #include <glibmm.h>
 #include "portaudio_io.h"
 
+#include "pbd/compose.h"
+
+#include "debug.h"
+
 #define INTERLEAVED_INPUT
 #define INTERLEAVED_OUTPUT
 
@@ -69,9 +74,9 @@ PortAudioIO::available_sample_rates(int device_id, std::vector<float>& sampleRat
 	if (device_id == -1) {
 		device_id = get_default_input_device ();
 	}
-#ifndef NDEBUG
-	printf("PortAudio: Querying Samplerates for device %d\n", device_id);
-#endif
+
+	DEBUG_AUDIO (
+	    string_compose ("Querying Samplerates for device %1\n", device_id));
 
 	sampleRates.clear();
 	const PaDeviceInfo* nfo = Pa_GetDeviceInfo(device_id);
@@ -181,7 +186,7 @@ PortAudioIO::set_host_api (const std::string& host_api_name)
 	_host_api_index = get_host_api_index_from_name (host_api_name);
 
 	if (_host_api_index < 0) {
-		fprintf(stderr, "Error setting host API\n");
+		DEBUG_AUDIO ("Error setting host API\n");
 	}
 }
 
@@ -192,7 +197,10 @@ PortAudioIO::get_host_api_index_from_name (const std::string& name)
 
 	PaHostApiIndex count = Pa_GetHostApiCount();
 
-	if (count < 0) return -1;
+	if (count < 0) {
+		DEBUG_AUDIO ("Host API count < 0\n");
+		return -1;
+	}
 
 	for (int i = 0; i < count; ++i) {
 		const PaHostApiInfo* info = Pa_GetHostApiInfo (i);
@@ -200,6 +208,8 @@ PortAudioIO::get_host_api_index_from_name (const std::string& name)
 			if (name == info->name) return i;
 		}
 	}
+	DEBUG_AUDIO (string_compose ("Unable to get host API from name: %1\n", name));
+
 	return -1;
 }
 
@@ -262,26 +272,28 @@ PortAudioIO::add_devices ()
 	if (info == NULL) return;
 
 	int n_devices = Pa_GetDeviceCount();
-#ifndef NDEBUG
-	printf("PortAudio %d devices found:\n", n_devices);
-#endif
+
+	DEBUG_AUDIO (string_compose ("PortAudio found %1 devices\n", n_devices));
 
 	for (int i = 0 ; i < n_devices; ++i) {
 		const PaDeviceInfo* nfo = Pa_GetDeviceInfo(i);
 
 		if (!nfo) continue;
 		if (nfo->hostApi != _host_api_index) continue;
-#ifndef NDEBUG
-		printf(" (%d) '%s' '%s' in: %d (lat: %.1f .. %.1f) out: %d (lat: %.1f .. %.1f) sr:%.2f\n",
-				i, info->name, nfo->name,
-				nfo->maxInputChannels,
-				nfo->defaultLowInputLatency * 1e3,
-				nfo->defaultHighInputLatency * 1e3,
-				nfo->maxOutputChannels,
-				nfo->defaultLowOutputLatency * 1e3,
-				nfo->defaultHighOutputLatency * 1e3,
-				nfo->defaultSampleRate);
-#endif
+
+		DEBUG_AUDIO (string_compose (" (%1) '%2' '%3' in: %4 (lat: %5 .. %6) out: %7 "
+		                             "(lat: %8 .. %9) sr:%10\n",
+		                             i,
+		                             info->name,
+		                             nfo->name,
+		                             nfo->maxInputChannels,
+		                             nfo->defaultLowInputLatency * 1e3,
+		                             nfo->defaultHighInputLatency * 1e3,
+		                             nfo->maxOutputChannels,
+		                             nfo->defaultLowOutputLatency * 1e3,
+		                             nfo->defaultHighOutputLatency * 1e3,
+		                             nfo->defaultSampleRate));
+
 		if ( nfo->maxInputChannels == 0 && nfo->maxOutputChannels == 0) {
 			continue;
 		}
@@ -364,15 +376,13 @@ PortAudioIO::pcm_setup (
 {
 	_state = -2;
 
-	// TODO error reporting sans fprintf()
-
 	PaError err = paNoError;
 	const PaDeviceInfo *nfo_in;
 	const PaDeviceInfo *nfo_out;
 	const PaStreamInfo *nfo_s;
 		
 	if (!initialize_pa()) {
-		fprintf(stderr, "PortAudio Initialization Failed\n");
+		DEBUG_AUDIO ("PortAudio Initialization Failed\n");
 		goto error;
 	}
 
@@ -389,15 +399,14 @@ PortAudioIO::pcm_setup (
 	_cur_input_latency = 0;
 	_cur_output_latency = 0;
 
-#ifndef NDEBUG
-	printf("PortAudio Device IDs: i:%d o:%d\n", device_input, device_output);
-#endif
+	DEBUG_AUDIO (string_compose (
+	    "PortAudio Device IDs: i:%1 o:%2\n", device_input, device_output));
 
 	nfo_in = Pa_GetDeviceInfo(device_input);
 	nfo_out = Pa_GetDeviceInfo(device_output);
 
 	if (!nfo_in && ! nfo_out) {
-		fprintf(stderr, "PortAudio Cannot Query Device Info\n");
+		DEBUG_AUDIO ("PortAudio Cannot Query Device Info\n");
 		goto error;
 	}
 
@@ -409,29 +418,29 @@ PortAudioIO::pcm_setup (
 	}
 
 	if(_capture_channels == 0 && _playback_channels == 0) {
-		fprintf(stderr, "PortAudio no Input and no output channels.\n");
+		DEBUG_AUDIO ("PortAudio no input or output channels.\n");
 		goto error;
 	}
 
-
 #ifdef __APPLE__
 	// pa_mac_core_blocking.c pa_stable_v19_20140130
 	// BUG: ringbuffer alloc requires power-of-two chn count.
 	if ((_capture_channels & (_capture_channels - 1)) != 0) {
-		printf("Adjusted capture channes to power of two (portaudio rb bug)\n");
+		DEBUG_AUDIO (
+		    "Adjusted capture channels to power of two (portaudio rb bug)\n");
 		_capture_channels = lower_power_of_two (_capture_channels);
 	}
 
 	if ((_playback_channels & (_playback_channels - 1)) != 0) {
-		printf("Adjusted capture channes to power of two (portaudio rb bug)\n");
+		DEBUG_AUDIO (
+		    "Adjusted capture channels to power of two (portaudio rb bug)\n");
 		_playback_channels = lower_power_of_two (_playback_channels);
 	}
 #endif
-	
-#ifndef NDEBUG
-	printf("PortAudio Channels: in:%d out:%d\n",
-			_capture_channels, _playback_channels);
-#endif
+
+	DEBUG_AUDIO (string_compose ("PortAudio Channels: in:%1 out:%2\n",
+	                             _capture_channels,
+	                             _playback_channels));
 
 	PaStreamParameters inputParam;
 	PaStreamParameters outputParam;
@@ -471,13 +480,13 @@ PortAudioIO::pcm_setup (
 			NULL, NULL);
 
 	if (err != paNoError) {
-		fprintf(stderr, "PortAudio failed to start stream.\n");
+		DEBUG_AUDIO ("PortAudio failed to start stream.\n");
 		goto error;
 	}
 
 	nfo_s = Pa_GetStreamInfo (_stream);
 	if (!nfo_s) {
-		fprintf(stderr, "PortAudio failed to query stream information.\n");
+		DEBUG_AUDIO ("PortAudio failed to query stream information.\n");
 		pcm_stop();
 		goto error;
 	}
@@ -486,18 +495,22 @@ PortAudioIO::pcm_setup (
 	_cur_input_latency = nfo_s->inputLatency * _cur_sample_rate;
 	_cur_output_latency = nfo_s->outputLatency * _cur_sample_rate;
 
-#ifndef NDEBUG
-	printf("PA Sample Rate  %.1f SPS\n", _cur_sample_rate);
-	printf("PA Input Latency  %.1fms  %d spl\n", 1e3 * nfo_s->inputLatency, _cur_input_latency);
-	printf("PA Output Latency %.1fms  %d spl\n", 1e3 * nfo_s->outputLatency, _cur_output_latency);
-#endif
+	DEBUG_AUDIO (string_compose ("PA Sample Rate %1 SPS\n", _cur_sample_rate));
+
+	DEBUG_AUDIO (string_compose ("PA Input Latency %1ms, %2 spl\n",
+	                             1e3 * nfo_s->inputLatency,
+	                             _cur_input_latency));
+
+	DEBUG_AUDIO (string_compose ("PA Output Latency %1ms, %2 spl\n",
+	                             1e3 * nfo_s->outputLatency,
+	                             _cur_output_latency));
 
 	_state = 0;
 
 	if (_capture_channels > 0) {
 		_input_buffer = (float*) malloc (samples_per_period * _capture_channels * sizeof(float));
 		if (!_input_buffer) {
-			fprintf(stderr, "PortAudio failed to allocate input buffer.\n");
+			DEBUG_AUDIO ("PortAudio failed to allocate input buffer.\n");
 			pcm_stop();
 			goto error;
 		}
@@ -506,7 +519,7 @@ PortAudioIO::pcm_setup (
 	if (_playback_channels > 0) {
 		_output_buffer = (float*) calloc (samples_per_period * _playback_channels, sizeof(float));
 		if (!_output_buffer) {
-			fprintf(stderr, "PortAudio failed to allocate output buffer.\n");
+			DEBUG_AUDIO ("PortAudio failed to allocate output buffer.\n");
 			pcm_stop();
 			goto error;
 		}
diff --git a/libs/backends/portaudio/win_utils.cc b/libs/backends/portaudio/win_utils.cc
new file mode 100644
index 0000000000..7bda04ccf1
--- /dev/null
+++ b/libs/backends/portaudio/win_utils.cc
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 "win_utils.h"
+
+#include <windows.h>
+
+#include "pbd/compose.h"
+
+#include "debug.h"
+
+namespace {
+
+LARGE_INTEGER
+get_frequency ()
+{
+	LARGE_INTEGER freq;
+	QueryPerformanceFrequency(&freq);
+	return freq;
+}
+
+
+UINT&
+old_timer_resolution ()
+{
+	static UINT timer_res_ms = 0;
+	return timer_res_ms;
+}
+
+} // anon namespace
+
+namespace utils {
+
+bool
+set_min_timer_resolution ()
+{
+	TIMECAPS caps;
+
+	if (timeGetDevCaps (&caps, sizeof(TIMECAPS)) != TIMERR_NOERROR) {
+		DEBUG_TIMING ("Could not get timer device capabilities.\n");
+		return false;
+	} else {
+		old_timer_resolution () = caps.wPeriodMin;
+		if (timeBeginPeriod (caps.wPeriodMin) != TIMERR_NOERROR) {
+			DEBUG_TIMING (string_compose (
+			    "Could not set minimum timer resolution to %1(ms)\n", caps.wPeriodMin));
+			return false;
+		}
+	}
+
+	DEBUG_TIMING (string_compose ("Multimedia timer resolution set to %1(ms)\n",
+	                              caps.wPeriodMin));
+
+	return true;
+}
+
+bool
+reset_timer_resolution ()
+{
+	if (old_timer_resolution ()) {
+		if (timeEndPeriod (old_timer_resolution ()) != TIMERR_NOERROR) {
+			DEBUG_TIMING ("Could not reset timer resolution.\n");
+			return false;
+		}
+	}
+
+	DEBUG_TIMING (string_compose ("Multimedia timer resolution set to %1(ms)\n",
+	                              old_timer_resolution ()));
+
+	return true;
+}
+
+uint64_t get_microseconds ()
+{
+	static LARGE_INTEGER frequency = get_frequency ();
+	LARGE_INTEGER current_val;
+
+	QueryPerformanceCounter (&current_val);
+
+	return (uint64_t)(((double)current_val.QuadPart) /
+	                  ((double)frequency.QuadPart) * 1000000.0);
+}
+
+} // namespace utils
diff --git a/libs/backends/portaudio/win_utils.h b/libs/backends/portaudio/win_utils.h
new file mode 100644
index 0000000000..50576b9c5d
--- /dev/null
+++ b/libs/backends/portaudio/win_utils.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 WIN_UTILS_H
+#define WIN_UTILS_H
+
+#include "stdint.h"
+
+namespace utils {
+
+bool set_min_timer_resolution ();
+
+bool reset_timer_resolution ();
+
+uint64_t get_microseconds ();
+
+}
+
+#endif // WIN_UTILS_H
diff --git a/libs/backends/portaudio/winmmemidi_input_device.cc b/libs/backends/portaudio/winmmemidi_input_device.cc
new file mode 100644
index 0000000000..1067b46743
--- /dev/null
+++ b/libs/backends/portaudio/winmmemidi_input_device.cc
@@ -0,0 +1,366 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 "winmmemidi_input_device.h"
+
+#include <stdexcept>
+#include <cmath>
+
+#include "pbd/compose.h"
+
+#include "win_utils.h"
+#include "midi_util.h"
+
+#include "debug.h"
+
+static const uint32_t MIDI_BUFFER_SIZE = 32768;
+static const uint32_t SYSEX_BUFFER_SIZE = 32768;
+
+namespace ARDOUR {
+
+WinMMEMidiInputDevice::WinMMEMidiInputDevice (int index)
+	: m_handle(0)
+	, m_midi_buffer(new RingBuffer<uint8_t>(MIDI_BUFFER_SIZE))
+	, m_sysex_buffer(new uint8_t[SYSEX_BUFFER_SIZE])
+{
+	DEBUG_MIDI (string_compose ("Creating midi input device index: %1\n", index));
+
+	std::string error_msg;
+
+	if (!open (index, error_msg)) {
+		DEBUG_MIDI (error_msg);
+		throw std::runtime_error (error_msg);
+	}
+
+	// perhaps this should be called in open
+	if (!add_sysex_buffer (error_msg)) {
+		DEBUG_MIDI (error_msg);
+		std::string close_error;
+		if (!close (close_error)) {
+			DEBUG_MIDI (close_error);
+		}
+		throw std::runtime_error (error_msg);
+	}
+
+	set_device_name (index);
+}
+
+WinMMEMidiInputDevice::~WinMMEMidiInputDevice ()
+{
+	std::string error_msg;
+	if (!close (error_msg)) {
+		DEBUG_MIDI (error_msg);
+	}
+}
+
+bool
+WinMMEMidiInputDevice::open (UINT index, std::string& error_msg)
+{
+	MMRESULT result = midiInOpen (&m_handle,
+	                              index,
+	                              (DWORD_PTR) winmm_input_callback,
+	                              (DWORD_PTR) this,
+	                              CALLBACK_FUNCTION | MIDI_IO_STATUS);
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		return false;
+	}
+	DEBUG_MIDI (string_compose ("Opened MIDI device index %1\n", index));
+	return true;
+}
+
+bool
+WinMMEMidiInputDevice::close (std::string& error_msg)
+{
+	// return error message for first error encountered?
+	bool success = true;
+
+	MMRESULT result = midiInReset (m_handle);
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		DEBUG_MIDI (error_msg);
+		success = false;
+	}
+	result = midiInUnprepareHeader (m_handle, &m_sysex_header, sizeof(MIDIHDR));
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		DEBUG_MIDI (error_msg);
+		success = false;
+	}
+	result = midiInClose (m_handle);
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		DEBUG_MIDI (error_msg);
+		success = false;
+	}
+	m_handle = 0;
+	if (success) {
+		DEBUG_MIDI (string_compose ("Closed MIDI device: %1\n", name ()));
+	} else {
+		DEBUG_MIDI (string_compose ("Unable to Close MIDI device: %1\n", name ()));
+	}
+	return success;
+}
+
+bool
+WinMMEMidiInputDevice::add_sysex_buffer (std::string& error_msg)
+{
+	m_sysex_header.dwBufferLength = SYSEX_BUFFER_SIZE;
+	m_sysex_header.dwFlags = 0;
+	m_sysex_header.lpData = (LPSTR)m_sysex_buffer.get ();
+
+	MMRESULT result = midiInPrepareHeader (m_handle, &m_sysex_header, sizeof(MIDIHDR));
+
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		DEBUG_MIDI (error_msg);
+		return false;
+	}
+	result = midiInAddBuffer (m_handle, &m_sysex_header, sizeof(MIDIHDR));
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		DEBUG_MIDI (error_msg);
+		return false;
+	}
+	return true;
+}
+
+bool
+WinMMEMidiInputDevice::set_device_name (UINT index)
+{
+	MIDIINCAPS capabilities;
+	MMRESULT result = midiInGetDevCaps (index, &capabilities, sizeof(capabilities));
+	if (result != MMSYSERR_NOERROR) {
+		DEBUG_MIDI (get_error_string (result));
+		m_name = "Unknown Midi Input Device";
+		return false;
+	} else {
+		m_name = capabilities.szPname;
+	}
+	return true;
+}
+
+std::string
+WinMMEMidiInputDevice::get_error_string (MMRESULT error_code)
+{
+	char error_msg[MAXERRORLENGTH];
+	MMRESULT result = midiInGetErrorText (error_code, error_msg, MAXERRORLENGTH);
+	if (result != MMSYSERR_NOERROR) {
+		return error_msg;
+	}
+	return "WinMMEMidiInput: Unknown Error code";
+}
+
+void CALLBACK
+WinMMEMidiInputDevice::winmm_input_callback(HMIDIIN handle,
+                                            UINT msg,
+                                            DWORD_PTR instance,
+                                            DWORD_PTR midi_msg,
+                                            DWORD timestamp)
+{
+	WinMMEMidiInputDevice* midi_input = (WinMMEMidiInputDevice*)instance;
+
+	switch (msg) {
+	case MIM_OPEN:
+	case MIM_CLOSE:
+		// devices_changed_callback
+		break;
+	case MIM_MOREDATA:
+		// passing MIDI_IO_STATUS to midiInOpen means that MIM_MOREDATA
+		// will be sent when the callback isn't processing MIM_DATA messages
+		// fast enough to keep up with messages arriving at input device
+		// driver. I'm not sure what could be done differently if that occurs
+		// so just handle MIM_DATA as per normal
+	case MIM_DATA:
+		midi_input->handle_short_msg ((const uint8_t*)&midi_msg, (uint32_t)timestamp);
+		break;
+	case MIM_LONGDATA:
+		midi_input->handle_sysex_msg ((MIDIHDR*)&midi_msg, (uint32_t)timestamp);
+		break;
+	case MIM_ERROR:
+		DEBUG_MIDI ("WinMME: Driver sent an invalid MIDI message\n");
+		break;
+	case MIM_LONGERROR:
+		DEBUG_MIDI ("WinMME: Driver sent an invalid or incomplete SYSEX message\n");
+		break;
+	}
+}
+
+void
+WinMMEMidiInputDevice::handle_short_msg (const uint8_t* midi_data,
+                                         uint32_t timestamp)
+{
+	int length = get_midi_msg_length (midi_data[0]);
+
+	if (length == 0 || length == -1) {
+		DEBUG_MIDI ("ERROR: midi input driver sent an invalid midi message\n");
+		return;
+	}
+
+	enqueue_midi_msg (midi_data, length, timestamp);
+}
+
+void
+WinMMEMidiInputDevice::handle_sysex_msg (MIDIHDR* const midi_header,
+                                         uint32_t timestamp)
+{
+#ifdef ENABLE_SYSEX
+	LPMIDIHDR header = (LPMIDIHDR)midi_header;
+	size_t byte_count = header->dwBytesRecorded;
+
+	if (!byte_count) {
+		DEBUG_MIDI (
+		    "ERROR: WinMME driver has returned sysex header to us with no bytes\n");
+		return;
+	}
+
+	uint8_t* data = (uint8_t*)header->lpData;
+
+	if ((data[0] != 0xf0) || (data[byte_count - 1] != 0xf7)) {
+		DEBUG_MIDI (string_compose ("Discarding %1 byte sysex chunk\n", byte_count));
+	} else {
+		enqueue_midi_msg (data, byte_count, timestamp);
+	}
+
+	MMRESULT result = midiInAddBuffer (m_handle, &m_sysex_header, sizeof(MIDIHDR));
+	if (result != MMSYSERR_NOERROR) {
+		DEBUG_MIDI (get_error_string (result));
+	}
+#endif
+}
+
+// fix param order
+bool
+WinMMEMidiInputDevice::dequeue_midi_event (uint64_t timestamp_start,
+                                           uint64_t timestamp_end,
+                                           uint64_t& timestamp,
+                                           uint8_t* midi_data,
+                                           size_t& data_size)
+{
+	const uint32_t read_space = m_midi_buffer->read_space();
+	struct MidiEventHeader h(0,0);
+
+	if (read_space <= sizeof(MidiEventHeader)) {
+		return false;
+	}
+
+	RingBuffer<uint8_t>::rw_vector vector;
+	m_midi_buffer->get_read_vector (&vector);
+	if (vector.len[0] >= sizeof(MidiEventHeader)) {
+		memcpy ((uint8_t*)&h, vector.buf[0], sizeof(MidiEventHeader));
+	} else {
+		if (vector.len[0] > 0) {
+			memcpy ((uint8_t*)&h, vector.buf[0], vector.len[0]);
+		}
+		assert (vector.buf[1] || vector.len[0] == sizeof(MidiEventHeader));
+		memcpy (((uint8_t*)&h) + vector.len[0],
+		        vector.buf[1],
+		        sizeof(MidiEventHeader) - vector.len[0]);
+	}
+
+	if (h.time >= timestamp_end) {
+		DEBUG_TIMING (string_compose ("WinMMEMidiInput EVENT %1(ms) early\n",
+		                              (h.time - timestamp_end) * 1e-3));
+		return false;
+	} else if (h.time < timestamp_start) {
+		DEBUG_TIMING (string_compose ("WinMMEMidiInput EVENT %1(ms) late\n",
+		                              (timestamp_start - h.time) * 1e-3));
+	}
+
+	m_midi_buffer->increment_read_idx (sizeof(MidiEventHeader));
+
+	assert (h.size > 0);
+	if (h.size > data_size) {
+		DEBUG_MIDI ("WinMMEMidiInput::dequeue_event MIDI event too large!\n");
+		m_midi_buffer->increment_read_idx (h.size);
+		return false;
+	}
+	if (m_midi_buffer->read (&midi_data[0], h.size) != h.size) {
+		DEBUG_MIDI ("WinMMEMidiInput::dequeue_event Garbled MIDI EVENT DATA!!\n");
+		return false;
+	}
+	timestamp = h.time;
+	data_size = h.size;
+	return true;
+}
+
+bool
+WinMMEMidiInputDevice::enqueue_midi_msg (const uint8_t* midi_data,
+                                         size_t data_size,
+                                         uint32_t timestamp)
+{
+	const uint32_t total_size = sizeof(MidiEventHeader) + data_size;
+
+	if (data_size == 0) {
+		DEBUG_MIDI ("ERROR: zero length midi data\n");
+		return false;
+	}
+
+	if (m_midi_buffer->write_space () < total_size) {
+		DEBUG_MIDI ("WinMMEMidiInput: ring buffer overflow\n");
+		return false;
+	}
+
+	// don't use winmme timestamps for now
+	uint64_t ts = utils::get_microseconds ();
+
+	DEBUG_TIMING (string_compose (
+	    "Enqueing MIDI data device: %1 with timestamp: %2 and size %3\n",
+	    name (),
+	    ts,
+	    data_size));
+
+	struct MidiEventHeader h (ts, data_size);
+	m_midi_buffer->write ((uint8_t*)&h, sizeof(MidiEventHeader));
+	m_midi_buffer->write (midi_data, data_size);
+	return true;
+}
+
+bool
+WinMMEMidiInputDevice::start ()
+{
+	if (!m_started) {
+		MMRESULT result = midiInStart (m_handle);
+		m_started = (result == MMSYSERR_NOERROR);
+		if (!m_started) {
+			DEBUG_MIDI (get_error_string (result));
+		} else {
+			DEBUG_MIDI (
+			    string_compose ("WinMMEMidiInput: device %1 started\n", name ()));
+		}
+	}
+	return m_started;
+}
+
+bool
+WinMMEMidiInputDevice::stop ()
+{
+	if (m_started) {
+		MMRESULT result = midiInStop (m_handle);
+		m_started = (result != MMSYSERR_NOERROR);
+		if (m_started) {
+			DEBUG_MIDI (get_error_string (result));
+		} else {
+			DEBUG_MIDI (
+			    string_compose ("WinMMEMidiInput: device %1 stopped\n", name ()));
+		}
+	}
+	return !m_started;
+}
+
+} // namespace ARDOUR
diff --git a/libs/backends/portaudio/winmmemidi_input_device.h b/libs/backends/portaudio/winmmemidi_input_device.h
new file mode 100644
index 0000000000..dab8dbfd53
--- /dev/null
+++ b/libs/backends/portaudio/winmmemidi_input_device.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 WINMME_MIDI_INPUT_DEVICE_H
+#define WINMME_MIDI_INPUT_DEVICE_H
+
+#include <windows.h>
+#include <mmsystem.h>
+
+#include <stdint.h>
+
+#include <string>
+
+#include <boost/scoped_array.hpp>
+#include <boost/scoped_ptr.hpp>
+
+#include <pbd/ringbuffer.h>
+
+namespace ARDOUR {
+
+class WinMMEMidiInputDevice {
+public: // ctors
+	WinMMEMidiInputDevice (int index);
+
+	~WinMMEMidiInputDevice ();
+
+public: // methods
+
+	/**
+	 * Dequeue events that have accumulated in winmm_input_callback.
+	 *
+	 * This is called by the audio processing thread/callback to transfer events
+	 * into midi ports before processing.
+	 */
+	bool dequeue_midi_event (uint64_t timestamp_start,
+	                         uint64_t timestamp_end,
+	                         uint64_t& timestamp,
+	                         uint8_t* data,
+	                         size_t& size);
+
+	bool start ();
+	bool stop ();
+
+	void set_enabled (bool enable);
+
+	bool get_enabled ();
+
+	/**
+	 * @return Name of midi device
+	 */
+	std::string name () const { return m_name; }
+
+private: // methods
+	bool open (UINT index, std::string& error_msg);
+	bool close (std::string& error_msg);
+
+	bool add_sysex_buffer (std::string& error_msg);
+	bool set_device_name (UINT index);
+
+	std::string get_error_string (MMRESULT error_code);
+
+	static void CALLBACK winmm_input_callback (HMIDIIN handle,
+	                                           UINT msg,
+	                                           DWORD_PTR instance,
+	                                           DWORD_PTR midi_msg,
+	                                           DWORD timestamp);
+
+	void handle_short_msg (const uint8_t* midi_data, uint32_t timestamp);
+
+	void handle_sysex_msg (MIDIHDR* const midi_header, uint32_t timestamp);
+
+	bool enqueue_midi_msg (const uint8_t* midi_data, size_t size, uint32_t timestamp);
+
+private: // data
+	HMIDIIN m_handle;
+	MIDIHDR m_sysex_header;
+
+	bool m_started;
+	bool m_enabled;
+
+	std::string m_name;
+
+	// can't use unique_ptr yet
+	boost::scoped_ptr<RingBuffer<uint8_t> > m_midi_buffer;
+	boost::scoped_array<uint8_t> m_sysex_buffer;
+};
+
+}
+
+#endif // WINMME_MIDI_INPUT_DEVICE_H
diff --git a/libs/backends/portaudio/winmmemidi_io.cc b/libs/backends/portaudio/winmmemidi_io.cc
new file mode 100644
index 0000000000..710456da0b
--- /dev/null
+++ b/libs/backends/portaudio/winmmemidi_io.cc
@@ -0,0 +1,294 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 <windows.h>
+#include <mmsystem.h>
+
+#include <sstream>
+
+#include "pbd/error.h"
+#include "pbd/compose.h"
+
+#include "winmmemidi_io.h"
+#include "win_utils.h"
+#include "debug.h"
+
+#include "i18n.h"
+
+using namespace ARDOUR;
+using namespace utils;
+
+WinMMEMidiIO::WinMMEMidiIO()
+	: m_active (false)
+	, m_enabled (true)
+	, m_run (false)
+	, m_changed_callback (0)
+	, m_changed_arg (0)
+{
+	pthread_mutex_init (&m_device_lock, 0);
+}
+
+WinMMEMidiIO::~WinMMEMidiIO()
+{
+	pthread_mutex_lock (&m_device_lock);
+	cleanup();
+	pthread_mutex_unlock (&m_device_lock);
+	pthread_mutex_destroy (&m_device_lock);
+}
+
+void
+WinMMEMidiIO::cleanup()
+{
+	DEBUG_MIDI ("MIDI cleanup\n");
+	m_active = false;
+
+	destroy_input_devices ();
+	destroy_output_devices ();
+}
+
+bool
+WinMMEMidiIO::dequeue_input_event (uint32_t port,
+                                   uint64_t timestamp_start,
+                                   uint64_t timestamp_end,
+                                   uint64_t &timestamp,
+                                   uint8_t *d,
+                                   size_t &s)
+{
+	if (!m_active) {
+		return false;
+	}
+	assert(port < m_inputs.size());
+
+	// m_inputs access should be protected by trylock
+	return m_inputs[port]->dequeue_midi_event (
+	    timestamp_start, timestamp_end, timestamp, d, s);
+}
+
+bool
+WinMMEMidiIO::enqueue_output_event (uint32_t port,
+                                    uint64_t timestamp,
+                                    const uint8_t *d,
+                                    const size_t s)
+{
+	if (!m_active) {
+		return false;
+	}
+	assert(port < m_outputs.size());
+
+	// m_outputs access should be protected by trylock
+	return m_outputs[port]->enqueue_midi_event (timestamp, d, s);
+}
+
+
+std::string
+WinMMEMidiIO::port_id (uint32_t port, bool input)
+{
+	std::stringstream ss;
+
+	if (input) {
+		ss << "system:midi_capture_";
+		ss << port;
+	} else {
+		ss << "system:midi_playback_";
+		ss << port;
+	}
+	return ss.str();
+}
+
+std::string
+WinMMEMidiIO::port_name (uint32_t port, bool input)
+{
+	if (input) {
+		if (port < m_inputs.size ()) {
+			return m_inputs[port]->name ();
+		}
+	} else {
+		if (port < m_outputs.size ()) {
+			return m_outputs[port]->name ();
+		}
+	}
+	return "";
+}
+
+void
+WinMMEMidiIO::start ()
+{
+	if (m_run) {
+		DEBUG_MIDI ("MIDI driver already started\n");
+		return;
+	}
+
+	m_run = true;
+	DEBUG_MIDI ("Starting MIDI driver\n");
+
+	set_min_timer_resolution();
+	discover();
+	start_devices ();
+}
+
+
+void
+WinMMEMidiIO::stop ()
+{
+	DEBUG_MIDI ("Stopping MIDI driver\n");
+	m_run = false;
+	stop_devices ();
+	pthread_mutex_lock (&m_device_lock);
+	cleanup ();
+	pthread_mutex_unlock (&m_device_lock);
+
+	reset_timer_resolution();
+}
+
+void
+WinMMEMidiIO::start_devices ()
+{
+	for (std::vector<WinMMEMidiInputDevice*>::iterator i = m_inputs.begin ();
+	     i < m_inputs.end();
+	     ++i) {
+		if (!(*i)->start ()) {
+			PBD::error << string_compose (_("Unable to start MIDI input device %1\n"),
+			                              (*i)->name ()) << endmsg;
+		}
+	}
+	for (std::vector<WinMMEMidiOutputDevice*>::iterator i = m_outputs.begin ();
+	     i < m_outputs.end();
+	     ++i) {
+		if (!(*i)->start ()) {
+			PBD::error << string_compose (_ ("Unable to start MIDI output device %1\n"),
+			                              (*i)->name ()) << endmsg;
+		}
+	}
+}
+
+void
+WinMMEMidiIO::stop_devices ()
+{
+	for (std::vector<WinMMEMidiInputDevice*>::iterator i = m_inputs.begin ();
+	     i < m_inputs.end();
+	     ++i) {
+		if (!(*i)->stop ()) {
+			PBD::error << string_compose (_ ("Unable to stop MIDI input device %1\n"),
+			                              (*i)->name ()) << endmsg;
+		}
+	}
+	for (std::vector<WinMMEMidiOutputDevice*>::iterator i = m_outputs.begin ();
+	     i < m_outputs.end();
+	     ++i) {
+		if (!(*i)->stop ()) {
+			PBD::error << string_compose (_ ("Unable to stop MIDI output device %1\n"),
+			                              (*i)->name ()) << endmsg;
+		}
+	}
+}
+
+void
+WinMMEMidiIO::create_input_devices ()
+{
+	int srcCount = midiInGetNumDevs ();
+
+	DEBUG_MIDI (string_compose ("MidiIn count: %1\n", srcCount));
+
+	for (int i = 0; i < srcCount; ++i) {
+		try {
+			WinMMEMidiInputDevice* midi_input = new WinMMEMidiInputDevice (i);
+			if (midi_input) {
+				m_inputs.push_back (midi_input);
+			}
+		}
+		catch (...) {
+			DEBUG_MIDI ("Unable to create MIDI input\n");
+			continue;
+		}
+	}
+}
+void
+WinMMEMidiIO::create_output_devices ()
+{
+	int dstCount = midiOutGetNumDevs ();
+
+	DEBUG_MIDI (string_compose ("MidiOut count: %1\n", dstCount));
+
+	for (int i = 0; i < dstCount; ++i) {
+		try {
+			WinMMEMidiOutputDevice* midi_output = new WinMMEMidiOutputDevice(i);
+			if (midi_output) {
+				m_outputs.push_back(midi_output);
+			}
+		} catch(...) {
+			DEBUG_MIDI ("Unable to create MIDI output\n");
+			continue;
+		}
+	}
+}
+
+void
+WinMMEMidiIO::destroy_input_devices ()
+{
+	while (!m_inputs.empty ()) {
+		WinMMEMidiInputDevice* midi_input = m_inputs.back ();
+		// assert(midi_input->stopped ());
+		m_inputs.pop_back ();
+		delete midi_input;
+	}
+}
+
+void
+WinMMEMidiIO::destroy_output_devices ()
+{
+	while (!m_outputs.empty ()) {
+		WinMMEMidiOutputDevice* midi_output = m_outputs.back ();
+		// assert(midi_output->stopped ());
+		m_outputs.pop_back ();
+		delete midi_output;
+	}
+}
+
+void
+WinMMEMidiIO::discover()
+{
+	if (!m_run) {
+		return;
+	}
+
+	if (pthread_mutex_trylock (&m_device_lock)) {
+		return;
+	}
+
+	cleanup ();
+
+	create_input_devices ();
+	create_output_devices ();
+
+	if (!(m_inputs.size () || m_outputs.size ())) {
+		DEBUG_MIDI ("No midi inputs or outputs\n");
+		pthread_mutex_unlock (&m_device_lock);
+		return;
+	}
+
+	DEBUG_MIDI (string_compose ("Discovered %1 inputs and %2 outputs\n",
+	                            m_inputs.size (),
+	                            m_outputs.size ()));
+
+	if (m_changed_callback) {
+		m_changed_callback(m_changed_arg);
+	}
+
+	m_active = true;
+	pthread_mutex_unlock (&m_device_lock);
+}
diff --git a/libs/backends/portaudio/winmmemidi_io.h b/libs/backends/portaudio/winmmemidi_io.h
new file mode 100644
index 0000000000..a2868241d8
--- /dev/null
+++ b/libs/backends/portaudio/winmmemidi_io.h
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 WINMME_MIDI_IO_H
+#define WINMME_MIDI_IO_H
+
+#include <map>
+#include <vector>
+#include <string>
+#include <stdint.h>
+
+#include <boost/shared_ptr.hpp>
+#include "pbd/ringbuffer.h"
+
+#include "winmmemidi_input_device.h"
+#include "winmmemidi_output_device.h"
+
+namespace ARDOUR {
+
+struct WinMMEMIDIPacket {
+
+#if 0
+	WinMMEMIDIPacket (const WinMMEMIDIPacket& other)
+	    : timeStamp (other.timeStamp)
+	    , length (other.length)
+	{
+		if (length > 0) {
+			memcpy (data, other.data, length);
+		}
+	}
+#endif
+
+	// MIDITimeStamp timeStamp;
+	uint16_t length;
+	uint8_t data[256];
+};
+
+typedef std::vector<boost::shared_ptr<WinMMEMIDIPacket> > WinMMEMIDIQueue;
+
+class WinMMEMidiIO {
+public:
+	WinMMEMidiIO ();
+	~WinMMEMidiIO ();
+
+	void start ();
+	void stop ();
+
+	bool dequeue_input_event (uint32_t port,
+	                          uint64_t timestamp_start,
+	                          uint64_t timestamp_end,
+	                          uint64_t& timestamp,
+	                          uint8_t* data,
+	                          size_t& size);
+
+	bool enqueue_output_event (uint32_t port,
+	                           uint64_t timestamp,
+	                           const uint8_t* data,
+	                           const size_t size);
+
+	uint32_t n_midi_inputs (void) const { return m_inputs.size(); }
+	uint32_t n_midi_outputs (void) const { return m_outputs.size(); }
+
+	std::vector<WinMMEMidiInputDevice*> get_inputs () { return m_inputs; }
+	std::vector<WinMMEMidiOutputDevice*> get_outputs () { return m_outputs; }
+
+	std::string port_id (uint32_t, bool input);
+	std::string port_name (uint32_t, bool input);
+
+	void set_enabled (bool yn = true) { m_enabled = yn; }
+	bool enabled (void) const { return m_active && m_enabled; }
+
+	void set_port_changed_callback (void (changed_callback (void*)), void *arg) {
+		m_changed_callback = changed_callback;
+		m_changed_arg = arg;
+	}
+
+private: // Methods
+	void discover ();
+	void cleanup ();
+
+	void create_input_devices ();
+	void create_output_devices ();
+
+	void destroy_input_devices ();
+	void destroy_output_devices ();
+
+	void start_devices ();
+	void stop_devices ();
+
+private: // Data
+
+	std::vector<WinMMEMidiInputDevice*> m_inputs;
+	std::vector<WinMMEMidiOutputDevice*> m_outputs;
+
+	bool              m_active;
+	bool              m_enabled;
+	bool              m_run;
+
+	void (* m_changed_callback) (void*);
+	void  * m_changed_arg;
+
+	// protects access to m_inputs and m_outputs
+	pthread_mutex_t m_device_lock;
+};
+
+} // namespace
+
+#endif // WINMME_MIDI_IO_H
+
diff --git a/libs/backends/portaudio/winmmemidi_output_device.cc b/libs/backends/portaudio/winmmemidi_output_device.cc
new file mode 100644
index 0000000000..6b31488b00
--- /dev/null
+++ b/libs/backends/portaudio/winmmemidi_output_device.cc
@@ -0,0 +1,494 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 "winmmemidi_output_device.h"
+
+#include <glibmm.h>
+
+#include "pbd/debug.h"
+#include "pbd/compose.h"
+
+#include "rt_thread.h"
+#include "win_utils.h"
+#include "midi_util.h"
+
+#include "debug.h"
+
+// remove dup with input_device
+static const uint32_t MIDI_BUFFER_SIZE = 32768;
+static const uint32_t MAX_MIDI_MSG_SIZE = 256; // fix this for sysex
+static const uint32_t MAX_QUEUE_SIZE = 4096;
+
+namespace ARDOUR {
+
+WinMMEMidiOutputDevice::WinMMEMidiOutputDevice (int index)
+	: m_handle(0)
+	, m_queue_semaphore(0)
+	, m_sysex_semaphore(0)
+	, m_timer(0)
+	, m_started(false)
+	, m_enabled(false)
+	, m_thread_running(false)
+	, m_thread_quit(false)
+	, m_midi_buffer(new RingBuffer<uint8_t>(MIDI_BUFFER_SIZE))
+{
+	DEBUG_MIDI (string_compose ("Creating midi output device index: %1\n", index));
+
+	std::string error_msg;
+
+	if (!open (index, error_msg)) {
+		DEBUG_MIDI (error_msg);
+		throw std::runtime_error (error_msg);
+	}
+
+	set_device_name (index);
+}
+
+WinMMEMidiOutputDevice::~WinMMEMidiOutputDevice ()
+{
+	std::string error_msg;
+	if (!close (error_msg)) {
+		DEBUG_MIDI (error_msg);
+	}
+}
+
+bool
+WinMMEMidiOutputDevice::enqueue_midi_event (uint64_t timestamp,
+                                            const uint8_t* data,
+                                            size_t size)
+{
+	const uint32_t total_bytes = sizeof(MidiEventHeader) + size;
+	if (m_midi_buffer->write_space () < total_bytes) {
+		DEBUG_MIDI ("WinMMEMidiOutput: ring buffer overflow\n");
+		return false;
+	}
+
+	MidiEventHeader h (timestamp, size);
+	m_midi_buffer->write ((uint8_t*)&h, sizeof(MidiEventHeader));
+	m_midi_buffer->write (data, size);
+
+	signal (m_queue_semaphore);
+	return true;
+}
+
+bool
+WinMMEMidiOutputDevice::open (UINT index, std::string& error_msg)
+{
+	MMRESULT result = midiOutOpen (&m_handle,
+	                               index,
+	                               (DWORD_PTR)winmm_output_callback,
+	                               (DWORD_PTR) this,
+	                               CALLBACK_FUNCTION);
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		return false;
+	}
+
+	m_queue_semaphore = CreateSemaphore (NULL, 0, MAX_QUEUE_SIZE, NULL);
+	if (m_queue_semaphore == NULL) {
+		DEBUG_MIDI ("WinMMEMidiOutput: Unable to create queue semaphore\n");
+		return false;
+	}
+	m_sysex_semaphore = CreateSemaphore (NULL, 0, 1, NULL);
+	if (m_sysex_semaphore == NULL) {
+		DEBUG_MIDI ("WinMMEMidiOutput: Unable to create sysex semaphore\n");
+		return false;
+	}
+	return true;
+}
+
+bool
+WinMMEMidiOutputDevice::close (std::string& error_msg)
+{
+	// return error message for first error encountered?
+	bool success = true;
+	MMRESULT result = midiOutReset (m_handle);
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		DEBUG_MIDI (error_msg);
+		success = false;
+	}
+	result = midiOutClose (m_handle);
+	if (result != MMSYSERR_NOERROR) {
+		error_msg = get_error_string (result);
+		DEBUG_MIDI (error_msg);
+		success = false;
+	}
+
+	if (m_sysex_semaphore) {
+		if (!CloseHandle (m_sysex_semaphore)) {
+			DEBUG_MIDI ("WinMMEMidiOut Unable to close sysex semaphore\n");
+			success = false;
+		} else {
+			m_sysex_semaphore = 0;
+		}
+	}
+	if (m_queue_semaphore) {
+		if (!CloseHandle (m_queue_semaphore)) {
+			DEBUG_MIDI ("WinMMEMidiOut Unable to close queue semaphore\n");
+			success = false;
+		} else {
+			m_queue_semaphore = 0;
+		}
+	}
+
+	m_handle = 0;
+	return success;
+}
+
+bool
+WinMMEMidiOutputDevice::set_device_name (UINT index)
+{
+	MIDIOUTCAPS capabilities;
+	MMRESULT result =
+	    midiOutGetDevCaps (index, &capabilities, sizeof(capabilities));
+
+	if (result != MMSYSERR_NOERROR) {
+		DEBUG_MIDI (get_error_string (result));
+		m_name = "Unknown Midi Output Device";
+		return false;
+	} else {
+		m_name = capabilities.szPname;
+	}
+	return true;
+}
+
+std::string
+WinMMEMidiOutputDevice::get_error_string (MMRESULT error_code)
+{
+	char error_msg[MAXERRORLENGTH];
+	MMRESULT result = midiOutGetErrorText (error_code, error_msg, MAXERRORLENGTH);
+	if (result != MMSYSERR_NOERROR) {
+		return error_msg;
+	}
+	return "WinMMEMidiOutput: Unknown Error code";
+}
+
+bool
+WinMMEMidiOutputDevice::start ()
+{
+	if (m_thread_running) {
+		DEBUG_MIDI (
+		    string_compose ("WinMMEMidiOutput: device %1 already started\n", m_name));
+		return true;
+	}
+
+	m_timer = CreateWaitableTimer (NULL, FALSE, NULL);
+
+	if (!m_timer) {
+		DEBUG_MIDI ("WinMMEMidiOutput: unable to create waitable timer\n");
+		return false;
+	}
+
+	if (!start_midi_output_thread ()) {
+		DEBUG_MIDI ("WinMMEMidiOutput: Failed to start MIDI output thread\n");
+
+		if (!CloseHandle (m_timer)) {
+			DEBUG_MIDI ("WinMMEMidiOutput: unable to close waitable timer\n");
+		}
+		return false;
+	}
+	return true;
+}
+
+bool
+WinMMEMidiOutputDevice::stop ()
+{
+	if (!m_thread_running) {
+		DEBUG_MIDI ("WinMMEMidiOutputDevice: device already stopped\n");
+		return true;
+	}
+
+	if (!stop_midi_output_thread ()) {
+		DEBUG_MIDI ("WinMMEMidiOutput: Failed to start MIDI output thread\n");
+		return false;
+	}
+
+	if (!CloseHandle (m_timer)) {
+		DEBUG_MIDI ("WinMMEMidiOutput: unable to close waitable timer\n");
+		return false;
+	}
+	m_timer = 0;
+	return true;
+}
+
+bool
+WinMMEMidiOutputDevice::start_midi_output_thread ()
+{
+	m_thread_quit = false;
+
+	//pthread_attr_t attr;
+	size_t stacksize = 100000;
+
+	// TODO Use native threads
+	if (_realtime_pthread_create (SCHED_FIFO, -21, stacksize,
+				&m_output_thread_handle, midi_output_thread, this)) {
+		return false;
+	}
+
+	int timeout = 5000;
+	while (!m_thread_running && --timeout > 0) { Glib::usleep (1000); }
+	if (timeout == 0 || !m_thread_running) {
+		DEBUG_MIDI (string_compose ("Unable to start midi output device thread: %1\n",
+		                            m_name));
+		return false;
+	}
+	return true;
+}
+
+bool
+WinMMEMidiOutputDevice::stop_midi_output_thread ()
+{
+	int timeout = 5000;
+	m_thread_quit = true;
+
+	while (m_thread_running && --timeout > 0) { Glib::usleep (1000); }
+	if (timeout == 0 || m_thread_running) {
+		DEBUG_MIDI (string_compose ("Unable to stop midi output device thread: %1\n",
+		                             m_name));
+		return false;
+	}
+
+	void *status;
+	if (pthread_join (m_output_thread_handle, &status)) {
+		DEBUG_MIDI (string_compose ("Unable to join midi output device thread: %1\n",
+		                            m_name));
+		return false;
+	}
+	return true;
+}
+
+bool
+WinMMEMidiOutputDevice::signal (HANDLE semaphore)
+{
+	bool result = (bool)ReleaseSemaphore (semaphore, 1, NULL);
+	if (!result) {
+		DEBUG_MIDI ("WinMMEMidiOutDevice: Cannot release semaphore\n");
+	}
+	return result;
+}
+
+bool
+WinMMEMidiOutputDevice::wait (HANDLE semaphore)
+{
+	DWORD result = WaitForSingleObject (semaphore, INFINITE);
+	switch (result) {
+	case WAIT_FAILED:
+		DEBUG_MIDI ("WinMMEMidiOutDevice: WaitForSingleObject Failed\n");
+		break;
+	case WAIT_OBJECT_0:
+		return true;
+	default:
+		DEBUG_MIDI ("WinMMEMidiOutDevice: Unexpected result from WaitForSingleObject\n");
+	}
+	return false;
+}
+
+void CALLBACK
+WinMMEMidiOutputDevice::winmm_output_callback (HMIDIOUT handle,
+                                               UINT msg,
+                                               DWORD_PTR instance,
+                                               DWORD_PTR midi_data,
+                                               DWORD_PTR timestamp)
+{
+	((WinMMEMidiOutputDevice*)instance)
+	    ->midi_output_callback (msg, midi_data, timestamp);
+}
+
+void
+WinMMEMidiOutputDevice::midi_output_callback (UINT message,
+                                              DWORD_PTR midi_data,
+                                              DWORD_PTR timestamp)
+{
+	switch (message) {
+	case MOM_CLOSE:
+		DEBUG_MIDI ("WinMMEMidiOutput - MIDI device closed\n");
+		break;
+	case MOM_DONE:
+		signal (m_sysex_semaphore);
+		break;
+	case MOM_OPEN:
+		DEBUG_MIDI ("WinMMEMidiOutput - MIDI device opened\n");
+		break;
+	case MOM_POSITIONCB:
+		LPMIDIHDR header = (LPMIDIHDR)midi_data;
+		DEBUG_MIDI (string_compose ("WinMMEMidiOut - %1 bytes out of %2 bytes of "
+		                            "the current sysex message have been sent.\n",
+		                            header->dwOffset,
+		                            header->dwBytesRecorded));
+	}
+}
+
+void*
+WinMMEMidiOutputDevice::midi_output_thread (void *arg)
+{
+	WinMMEMidiOutputDevice* output_device = reinterpret_cast<WinMMEMidiOutputDevice*> (arg);
+	output_device->midi_output_thread ();
+	return 0;
+}
+
+void
+WinMMEMidiOutputDevice::midi_output_thread ()
+{
+	m_thread_running = true;
+
+	while (!m_thread_quit) {
+		if (!wait (m_queue_semaphore)) {
+			break;
+		}
+
+		MidiEventHeader h (0, 0);
+		uint8_t data[MAX_MIDI_MSG_SIZE];
+
+		const uint32_t read_space = m_midi_buffer->read_space ();
+
+		if (read_space > sizeof(MidiEventHeader)) {
+			if (m_midi_buffer->read ((uint8_t*)&h, sizeof(MidiEventHeader)) !=
+			    sizeof(MidiEventHeader)) {
+				DEBUG_MIDI ("WinMMEMidiOut: Garbled MIDI EVENT HEADER!!\n");
+				break;
+			}
+			assert (read_space >= h.size);
+
+			if (h.size > MAX_MIDI_MSG_SIZE) {
+				m_midi_buffer->increment_read_idx (h.size);
+				DEBUG_MIDI ("WinMMEMidiOut: MIDI event too large!\n");
+				continue;
+			}
+			if (m_midi_buffer->read (&data[0], h.size) != h.size) {
+				DEBUG_MIDI ("WinMMEMidiOut: Garbled MIDI EVENT DATA!!\n");
+				break;
+			}
+		} else {
+			// error/assert?
+			DEBUG_MIDI ("WinMMEMidiOut: MIDI buffer underrun, shouldn't occur\n");
+			continue;
+		}
+		uint64_t current_time = utils::get_microseconds ();
+
+		DEBUG_TIMING (string_compose (
+		    "WinMMEMidiOut: h.time = %1, current_time = %2\n", h.time, current_time));
+
+		if (h.time > current_time) {
+
+			DEBUG_TIMING (string_compose ("WinMMEMidiOut: waiting at %1 for %2 "
+			                              "milliseconds before sending message\n",
+			                              ((double)current_time) / 1000.0,
+			                              ((double)(h.time - current_time)) / 1000.0));
+
+			if (!wait_for_microseconds (h.time - current_time))
+			{
+				DEBUG_MIDI ("WinMMEMidiOut: Error waiting for timer\n");
+				break;
+			}
+
+			uint64_t wakeup_time = utils::get_microseconds ();
+			DEBUG_TIMING (string_compose ("WinMMEMidiOut: woke up at %1(ms)\n",
+			                              ((double)wakeup_time) / 1000.0));
+			if (wakeup_time > h.time) {
+				DEBUG_TIMING (string_compose ("WinMMEMidiOut: overslept by %1(ms)\n",
+				                              ((double)(wakeup_time - h.time)) / 1000.0));
+			} else if (wakeup_time < h.time) {
+				DEBUG_TIMING (string_compose ("WinMMEMidiOut: woke up %1(ms) too early\n",
+				                              ((double)(h.time - wakeup_time)) / 1000.0));
+			}
+
+		} else if (h.time < current_time) {
+			DEBUG_TIMING (string_compose (
+			    "WinMMEMidiOut: MIDI event at sent to driver %1(ms) late\n",
+			    ((double)(current_time - h.time)) / 1000.0));
+		}
+
+		DWORD message = 0;
+		MMRESULT result;
+		switch (h.size) {
+		case 3:
+			message |= (((DWORD)data[2]) << 16);
+		// Fallthrough on purpose.
+		case 2:
+			message |= (((DWORD)data[1]) << 8);
+		// Fallthrough on purpose.
+		case 1:
+			message |= (DWORD)data[0];
+			result = midiOutShortMsg (m_handle, message);
+			if (result != MMSYSERR_NOERROR) {
+				DEBUG_MIDI (
+				    string_compose ("WinMMEMidiOutput: %1\n", get_error_string (result)));
+			}
+			continue;
+		}
+
+#if ENABLE_SYSEX
+		MIDIHDR header;
+		header.dwBufferLength = h.size;
+		header.dwFlags = 0;
+		header.lpData = (LPSTR)data;
+
+		result = midiOutPrepareHeader (m_handle, &header, sizeof(MIDIHDR));
+		if (result != MMSYSERR_NOERROR) {
+			DEBUG_MIDI (string_compose ("WinMMEMidiOutput: midiOutPrepareHeader %1\n",
+			                            get_error_string (result)));
+			continue;
+		}
+
+		result = midiOutLongMsg (m_handle, &header, sizeof(MIDIHDR));
+		if (result != MMSYSERR_NOERROR) {
+			DEBUG_MIDI (string_compose ("WinMMEMidiOutput: midiOutLongMsg %1\n",
+			                            get_error_string (result)));
+			continue;
+		}
+
+		// Sysex messages may be sent synchronously or asynchronously.  The
+		// choice is up to the WinMME driver.  So, we wait until the message is
+		// sent, regardless of the driver's choice.
+		if (!wait (m_sysex_semaphore)) {
+			break;
+		}
+
+		result = midiOutUnprepareHeader (m_handle, &header, sizeof(MIDIHDR));
+		if (result != MMSYSERR_NOERROR) {
+			DEBUG_MIDI (string_compose ("WinMMEMidiOutput: midiOutUnprepareHeader %1\n",
+			                            get_error_string (result)));
+			break;
+		}
+#endif
+	}
+
+	m_thread_running = false;
+}
+
+bool
+WinMMEMidiOutputDevice::wait_for_microseconds (int64_t wait_us)
+{
+	LARGE_INTEGER due_time;
+
+	// 100 ns resolution
+	due_time.QuadPart = -((LONGLONG)(wait_us * 10));
+	if (!SetWaitableTimer (m_timer, &due_time, 0, NULL, NULL, 0)) {
+		DEBUG_MIDI ("WinMMEMidiOut: Error waiting for timer\n");
+		return false;
+	}
+
+	if (!wait (m_timer)) {
+		return false;
+	}
+
+	return true;
+}
+
+} // namespace ARDOUR
diff --git a/libs/backends/portaudio/winmmemidi_output_device.h b/libs/backends/portaudio/winmmemidi_output_device.h
new file mode 100644
index 0000000000..ead85d7169
--- /dev/null
+++ b/libs/backends/portaudio/winmmemidi_output_device.h
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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 WINMME_MIDI_OUTPUT_DEVICE_H
+#define WINMME_MIDI_OUTPUT_DEVICE_H
+
+#include <windows.h>
+#include <mmsystem.h>
+
+#include <stdint.h>
+
+#include <string>
+
+#include <boost/scoped_ptr.hpp>
+
+#include <pbd/ringbuffer.h>
+
+namespace ARDOUR {
+
+class WinMMEMidiOutputDevice {
+public:
+	WinMMEMidiOutputDevice (int index);
+
+	~WinMMEMidiOutputDevice ();
+
+	bool enqueue_midi_event (uint64_t rel_event_time_us,
+	                         const uint8_t* data,
+	                         const size_t size);
+
+	bool start ();
+	bool stop ();
+
+	void set_enabled (bool enable);
+	bool get_enabled ();
+
+	std::string name () const { return m_name; }
+
+private: // Methods
+	bool open (UINT index, std::string& error_msg);
+	bool close (std::string& error_msg);
+
+	bool set_device_name (UINT index);
+
+	std::string get_error_string (MMRESULT error_code);
+
+	bool start_midi_output_thread ();
+	bool stop_midi_output_thread ();
+
+	bool signal (HANDLE semaphore);
+	bool wait (HANDLE semaphore);
+
+	static void* midi_output_thread (void*);
+	void midi_output_thread ();
+
+	bool wait_for_microseconds (int64_t us);
+
+	static void CALLBACK winmm_output_callback (HMIDIOUT handle,
+	                                            UINT msg,
+	                                            DWORD_PTR instance,
+	                                            DWORD_PTR midi_data,
+	                                            DWORD_PTR timestamp);
+
+	void midi_output_callback (UINT msg, DWORD_PTR data, DWORD_PTR timestamp);
+
+private: // Data
+	HMIDIOUT m_handle;
+
+	HANDLE m_queue_semaphore;
+	HANDLE m_sysex_semaphore;
+
+	HANDLE m_timer;
+
+	bool m_started;
+	bool m_enabled;
+
+	std::string m_name;
+
+	pthread_t m_output_thread_handle;
+
+	bool m_thread_running;
+	bool m_thread_quit;
+
+	boost::scoped_ptr<RingBuffer<uint8_t> > m_midi_buffer;
+};
+
+} // namespace ARDOUR
+
+#endif // WINMME_MIDI_OUTPUT_DEVICE_H
diff --git a/libs/backends/portaudio/wscript b/libs/backends/portaudio/wscript
index 4b77f9670b..8bcfa5fa46 100644
--- a/libs/backends/portaudio/wscript
+++ b/libs/backends/portaudio/wscript
@@ -22,7 +22,11 @@ def build(bld):
     obj = bld(features = 'cxx cxxshlib')
     obj.source = [ 'portaudio_backend.cc',
                    'portaudio_io.cc',
-#                  'portmidi_io.cc'
+                   'winmmemidi_io.cc',
+                   'winmmemidi_input_device.cc',
+                   'winmmemidi_output_device.cc',
+                   'win_utils.cc',
+                   'midi_util.cc'
                  ]
     obj.includes = ['.']
     obj.name     = 'portaudio_backend'
diff --git a/libs/pbd/debug.cc b/libs/pbd/debug.cc
index 9150cd6883..b42e7f047e 100644
--- a/libs/pbd/debug.cc
+++ b/libs/pbd/debug.cc
@@ -63,6 +63,11 @@ DebugBits PBD::DEBUG::Configuration = PBD::new_debug_bit ("configuration");
    from dynamically loaded code, for use in command line parsing, is way above the pay grade
    of this debug tracing scheme.
 */
+DebugBits PBD::DEBUG::BackendMIDI = PBD::new_debug_bit ("BackendMIDI");
+DebugBits PBD::DEBUG::BackendAudio = PBD::new_debug_bit ("BackendAudio");
+DebugBits PBD::DEBUG::BackendTiming = PBD::new_debug_bit ("BackendTiming");
+DebugBits PBD::DEBUG::BackendThreads = PBD::new_debug_bit ("BackendThreads");
+
 
 DebugBits PBD::DEBUG::WavesMIDI = PBD::new_debug_bit ("WavesMIDI");
 DebugBits PBD::DEBUG::WavesAudio = PBD::new_debug_bit ("WavesAudio");
diff --git a/libs/pbd/pbd/debug.h b/libs/pbd/pbd/debug.h
index 8beed56d41..cc3fbdcf55 100644
--- a/libs/pbd/pbd/debug.h
+++ b/libs/pbd/pbd/debug.h
@@ -56,6 +56,11 @@ namespace PBD {
 		LIBPBD_API extern DebugBits Configuration;
 		LIBPBD_API extern DebugBits FileUtils;
 
+		LIBPBD_API extern DebugBits BackendMIDI;
+		LIBPBD_API extern DebugBits BackendAudio;
+		LIBPBD_API extern DebugBits BackendTiming;
+		LIBPBD_API extern DebugBits BackendThreads;
+
 		/* See notes in ../debug.cc on why these are defined here */
 
                 LIBPBD_API extern DebugBits WavesMIDI;