Split jack_host into slv2_simple_jack_host and slv2_host, added MIDI support to slv2_host.

git-svn-id: http://svn.drobilla.net/lad/slv2@251 a436a847-0d15-0410-975c-d299462d15a1

6 files changed, 696 insertions, 10 deletions

diff --git a/examples/hosts/Makefile.am b/examples/hosts/Makefile.am
index 340c962..a5ffd44 100644
--- a/examples/hosts/Makefile.am
+++ b/examples/hosts/Makefile.am
@@ -1,24 +1,35 @@
 AM_CFLAGS = -std=c99 -I. -I$(top_srcdir)/include -I$(top_srcdir) `pkg-config --cflags rasqal`
 AM_LDFLAGS = `pkg-config --libs rasqal`
 
-bin_PROGRAMS = test_host jack_host
+bin_PROGRAMS = slv2_test_host slv2_simple_jack_host slv2_host
 
-test_host_DEPENDENCIES = ../../src/libslv2.la
-test_host_LDADD        = ../../src/libslv2.la
+slv2_test_host_DEPENDENCIES = ../../src/libslv2.la
+slv2_test_host_LDADD        = ../../src/libslv2.la
 
-test_host_SOURCES = \
+slv2_test_host_SOURCES = \
 	test_host.c
 
 
 if WITH_JACK
 
-jack_host_CFLAGS = @JACK_CFLAGS@ $(AM_CFLAGS)
-#jack_host_LIBS = @JACK_LIBS@
+slv2_simple_jack_host_CFLAGS = @JACK_CFLAGS@ $(AM_CFLAGS)
+#simple_jack_host_LIBS = @JACK_LIBS@
 
-jack_host_DEPENDENCIES = ../../src/libslv2.la
-jack_host_LDADD        = ../../src/libslv2.la @JACK_LIBS@
+slv2_simple_jack_host_DEPENDENCIES = ../../src/libslv2.la
+slv2_simple_jack_host_LDADD        = ../../src/libslv2.la @JACK_LIBS@
+
+slv2_simple_jack_host_SOURCES = \
+	simple_jack_host.c
+
+
+slv2_host_CFLAGS = @JACK_CFLAGS@ $(AM_CFLAGS)
+#host_LIBS = @JACK_LIBS@
+
+slv2_host_DEPENDENCIES = ../../src/libslv2.la
+slv2_host_LDADD        = ../../src/libslv2.la @JACK_LIBS@
+
+slv2_host_SOURCES = \
+	host.c
 
-jack_host_SOURCES = \
-	jack_host.c
 
 endif # WITH_JACK
diff --git a/examples/hosts/host.c b/examples/hosts/host.c
new file mode 100644
index 0000000..97937a8
--- /dev/null
+++ b/examples/hosts/host.c
@@ -0,0 +1,341 @@
+/* LibSLV2 Jack Example Host
+ * Copyright (C) 2006 Dave Robillard <drobilla@connect.carleton.ca>
+ *  
+ * 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.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <slv2/slv2.h>
+#include <jack/jack.h>
+
+#define WITH_MIDI 1
+#define MIDI_BUFFER_SIZE 1024
+
+#ifdef WITH_MIDI
+#include <jack/midiport.h>
+#include "lv2-miditype.h"
+#include "lv2-midifunctions.h"
+#endif // WITH_MIDI
+
+struct Port {
+	enum Direction { INPUT, OUTPUT}         direction;
+	enum Type      { UNKNOWN, FLOAT, MIDI } type;
+
+	jack_port_t* jack_port;   /**< For audio and MIDI ports, otherwise NULL */
+	float        control;     /**< For control ports, otherwise 0.0f */
+	LV2_MIDI*    midi_buffer; /**< For midi ports, otherwise NULL */
+};
+
+
+/** This program's data */
+struct JackHost {
+	jack_client_t* jack_client; /**< Jack client */
+	SLV2Plugin*    plugin;      /**< Plugin "class" (actually just a few strings) */
+	SLV2Instance*  instance;    /**< Plugin "instance" (loaded shared lib) */
+	uint32_t       num_ports;   /**< Size of the two following arrays: */
+	struct Port*   ports;       /** Port array of size num_ports */
+};
+
+
+void die(const char* msg);
+void create_port(struct JackHost* host, uint32_t port_index);
+int  jack_process_cb(jack_nframes_t nframes, void* data);
+void list_plugins(SLV2List list);
+
+
+int
+main(int argc, char** argv)
+{
+	struct JackHost host;
+	host.jack_client = NULL;
+	host.num_ports   = 0;
+	host.ports       = NULL;
+	
+	/* Find all installed plugins */
+	SLV2List plugins = slv2_list_new();
+	slv2_list_load_all(plugins);
+	//slv2_list_load_bundle(plugins, "http://www.scs.carleton.ca/~drobilla/files/Amp-swh.lv2");
+
+	/* Find the plugin to run */
+	const char* plugin_uri = (argc == 2) ? argv[1] : NULL;
+	
+	if (!plugin_uri) {
+		fprintf(stderr, "\nYou must specify a plugin URI to load.\n");
+		fprintf(stderr, "\nKnown plugins:\n\n");
+		list_plugins(plugins);
+		return EXIT_FAILURE;
+	}
+
+	printf("URI:\t%s\n", plugin_uri);
+	host.plugin = slv2_list_get_plugin_by_uri(plugins, plugin_uri);
+	
+	if (!host.plugin) {
+		fprintf(stderr, "Failed to find plugin %s.\n", plugin_uri);
+		slv2_list_free(plugins);
+		return EXIT_FAILURE;
+	}
+
+	/* Get the plugin's name */
+	char* name = slv2_plugin_get_name(host.plugin);
+	printf("Name:\t%s\n", name);
+	
+	/* Connect to JACK (with plugin name as client name) */
+	host.jack_client = jack_client_open(name, JackNullOption, NULL);
+	free(name);
+	if (!host.jack_client)
+		die("Failed to connect to JACK.");
+	else
+		printf("Connected to JACK.\n");
+	
+	/* Instantiate the plugin */
+	host.instance = slv2_plugin_instantiate(
+		host.plugin, jack_get_sample_rate(host.jack_client), NULL);
+	if (!host.instance)
+		die("Failed to instantiate plugin.\n");
+	else
+		printf("Succesfully instantiated plugin.\n");
+
+	jack_set_process_callback(host.jack_client, &jack_process_cb, (void*)(&host));
+	
+	/* Create ports */
+	host.num_ports  = slv2_plugin_get_num_ports(host.plugin);
+	host.ports = calloc((size_t)host.num_ports, sizeof(struct Port));
+	
+	for (uint32_t i=0; i < host.num_ports; ++i)
+		create_port(&host, i);
+	
+	/* Activate plugin and JACK */
+	slv2_instance_activate(host.instance);
+	jack_activate(host.jack_client);
+	
+	/* Run */
+	printf("Press enter to quit: ");
+	getc(stdin);
+	printf("\n");
+	
+	/* Deactivate plugin and JACK */
+	slv2_instance_free(host.instance);
+	slv2_list_free(plugins);
+	
+	printf("Shutting down JACK.\n");
+	for (unsigned long i=0; i < host.num_ports; ++i) {
+		if (host.ports[i].jack_port != NULL) {
+			jack_port_unregister(host.jack_client, host.ports[i].jack_port);
+			host.ports[i].jack_port = NULL;
+		}
+		if (host.ports[i].midi_buffer != NULL) {
+			lv2midi_free(host.ports[i].midi_buffer);
+		}
+	}
+	jack_client_close(host.jack_client);
+	
+	return 0;
+}
+
+
+/** Abort and exit on error */
+void
+die(const char* msg)
+{
+	fprintf(stderr, "%s\n", msg);
+	exit(EXIT_FAILURE);
+}
+
+
+/** Creates a port and connects the plugin instance to it's data location.
+ *
+ * For audio ports, creates a jack port and connects plugin port to buffer.
+ *
+ * For control ports, sets controls array to default value and connects plugin
+ * port to that element.
+ */
+void
+create_port(struct JackHost* host,
+            uint32_t         port_index)
+{
+	//struct Port* port = (Port*)malloc(sizeof(Port));
+	struct Port* const port = &host->ports[port_index];
+
+	port->type        = UNKNOWN;
+	port->jack_port   = NULL;
+	port->control     = 0.0f;
+	port->midi_buffer = NULL;
+	
+	slv2_instance_connect_port(host->instance, port_index, NULL);
+
+	char* type_str = slv2_port_get_data_type(host->plugin, port_index);
+	if (!strcmp(type_str, SLV2_DATA_TYPE_FLOAT))
+		port->type = FLOAT;
+	else if (!strcmp(type_str, SLV2_DATA_TYPE_MIDI))
+		port->type = MIDI;
+	
+	/* Get the port symbol (label) for console printing */
+	char* symbol = slv2_port_get_symbol(host->plugin, port_index);
+	
+	/* Get the 'class' (not data type) of the port (control input, audio output, etc) */
+	enum SLV2PortClass class = slv2_port_get_class(host->plugin, port_index);
+
+	if (port->type == FLOAT) {
+		
+		/* Connect the port based on it's 'class' */
+		switch (class) {
+		case SLV2_CONTROL_RATE_INPUT:
+			port->direction = INPUT;
+			port->control = slv2_port_get_default_value(host->plugin, port_index);
+			slv2_instance_connect_port(host->instance, port_index, &port->control);
+			printf("Set %s to %f\n", symbol, host->ports[port_index].control);
+			break;
+		case SLV2_CONTROL_RATE_OUTPUT:
+			port->direction = OUTPUT;
+			slv2_instance_connect_port(host->instance, port_index, &port->control);
+			break;
+		case SLV2_AUDIO_RATE_INPUT:
+			printf("AI!\n");
+			port->direction = INPUT;
+			port->jack_port = jack_port_register(host->jack_client,
+				symbol, JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0);
+			break;
+		case SLV2_AUDIO_RATE_OUTPUT:
+			printf("AO!\n");
+			port->direction = OUTPUT;
+			port->jack_port = jack_port_register(host->jack_client,
+				symbol, JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);
+			break;
+		default:
+			fprintf(stderr, "ERROR: Unknown port class\n");
+		}
+	
+	} else if (port->type == MIDI) {
+
+		printf("MIDI! %s\n", symbol);
+		if (class == SLV2_CONTROL_RATE_INPUT) {
+			port->direction = INPUT;
+			port->jack_port = jack_port_register(host->jack_client,
+				symbol, JACK_DEFAULT_MIDI_TYPE, JackPortIsInput, 0);
+			port->midi_buffer = lv2midi_new(MIDI_BUFFER_SIZE);
+			slv2_instance_connect_port(host->instance, port_index, port->midi_buffer);
+		} else if (class == SLV2_CONTROL_RATE_OUTPUT) {
+			port->direction = OUTPUT;
+			port->jack_port = jack_port_register(host->jack_client,
+				symbol, JACK_DEFAULT_MIDI_TYPE, JackPortIsOutput, 0);
+			port->midi_buffer = lv2midi_new(MIDI_BUFFER_SIZE);
+			slv2_instance_connect_port(host->instance, port_index, port->midi_buffer);
+		} else {
+			fprintf(stderr, "ERROR: Audio rate MIDI port??  Ignoring.\n");
+		}
+
+	} else {
+
+		fprintf(stderr, "Unrecognized data type %s for port %s, ignored.\n",
+				type_str, symbol);
+		fprintf(stderr, "                       %s\n",
+				SLV2_DATA_TYPE_MIDI);
+
+	}
+
+	free(symbol);
+	free(type_str);
+}
+
+
+/** Jack process callback. */
+int
+jack_process_cb(jack_nframes_t nframes, void* data)
+{
+	struct JackHost* const host = (struct JackHost*)data;
+
+	/* Connect inputs */
+	for (uint32_t p=0; p < host->num_ports; ++p) {
+		if (!host->ports[p].jack_port)
+			continue;
+
+		if (host->ports[p].type == FLOAT) {
+			slv2_instance_connect_port(host->instance, p,
+					jack_port_get_buffer(host->ports[p].jack_port, nframes));
+		} else if (host->ports[p].type == MIDI) {
+			
+			void* jack_buffer = jack_port_get_buffer(host->ports[p].jack_port, nframes);
+
+			LV2_MIDIState state;
+			lv2midi_reset_state(&state, host->ports[p].midi_buffer, nframes);
+			lv2midi_reset_buffer(state.midi);
+			
+			if (host->ports[p].direction == INPUT) {
+				jack_midi_event_t ev;
+
+				const jack_nframes_t event_count
+					= jack_midi_get_event_count(jack_buffer, nframes);
+
+				for (jack_nframes_t e=0; e < event_count; ++e) {
+
+					jack_midi_event_get(&ev, jack_buffer, e, nframes);
+
+					state.midi = host->ports[p].midi_buffer;
+					lv2midi_put_event(&state, (double)ev.time, ev.size, ev.buffer);
+				}
+			}
+		}
+	}
+	
+
+	/* Run plugin for this cycle */
+	slv2_instance_run(host->instance, nframes);
+
+
+	/* Deliver output */
+	for (uint32_t p=0; p < host->num_ports; ++p) {
+		if (host->ports[p].jack_port
+				&& host->ports[p].type == MIDI
+				&& host->ports[p].direction == OUTPUT) {
+
+			void* jack_buffer = jack_port_get_buffer(host->ports[p].jack_port, nframes);
+
+			jack_midi_clear_buffer(jack_buffer, nframes);
+
+			LV2_MIDIState state;
+			lv2midi_reset_state(&state, host->ports[p].midi_buffer, nframes);
+			
+			double         timestamp = 0.0f;
+			uint32_t       size      = 0;
+			unsigned char* data      = NULL;
+
+			const uint32_t event_count = state.midi->event_count;
+
+			for (uint32_t i=0; i < event_count; ++i) {
+				lv2midi_get_event(&state, &timestamp, &size, &data);
+
+				jack_midi_event_write(jack_buffer,
+						(jack_nframes_t)timestamp, data, size, nframes);
+
+				lv2midi_increment(&state);
+			}
+
+		}
+	}
+
+	return 0;
+}
+
+
+void
+list_plugins(SLV2List list)
+{
+	for (size_t i=0; i < slv2_list_get_length(list); ++i) {
+		const SLV2Plugin* const p = slv2_list_get_plugin_by_index(list, i);
+		printf("%s\n", slv2_plugin_get_uri(p));
+	}
+}
diff --git a/examples/hosts/lv2-midifunctions.h b/examples/hosts/lv2-midifunctions.h
new file mode 100644
index 0000000..68691f3
--- /dev/null
+++ b/examples/hosts/lv2-midifunctions.h
@@ -0,0 +1,161 @@
+/****************************************************************************
+    
+    lv2-midifunctions.h - support file for using MIDI in LV2 plugins
+    
+    Copyright (C) 2006  Lars Luthman <lars.luthman@gmail.com>
+    
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
+    
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307  USA
+
+****************************************************************************/
+
+#ifndef LV2_MIDIFUNCTIONS
+#define LV2_MIDIFUNCTIONS
+
+#include <string.h>
+
+#include "lv2-miditype.h"
+
+
+/** This structure contains information about a MIDI port buffer, the 
+    current period size, and the position in the MIDI data buffer that
+    we are currently reading from or writing to. It needs to be recreated
+    or at least reinitialised every process() call. */
+typedef struct {
+
+  /** The MIDI port structure that we want to read or write. */
+  LV2_MIDI* midi;
+  
+  /** The number of frames in this process cycle. */
+  uint32_t frame_count;
+  
+  /** The current position in the data buffer. Should be initialised to 0. */
+  uint32_t position;
+
+} LV2_MIDIState;
+
+
+static LV2_MIDI* lv2midi_new(uint32_t capacity)
+{
+	LV2_MIDI* midi = malloc(sizeof(LV2_MIDI));
+
+	midi->event_count = 0;
+	midi->capacity = capacity;
+	midi->size = 0;
+	midi->data = malloc(sizeof(char) * capacity);
+
+	return midi;
+}
+
+
+static void lv2midi_free(LV2_MIDI* midi)
+{
+	free(midi->data);
+	free(midi);
+}
+
+
+static void lv2midi_reset_buffer(LV2_MIDI* midi)
+{
+	midi->event_count = 0;
+	midi->size = 0;
+}
+
+static void lv2midi_reset_state(LV2_MIDIState* state, LV2_MIDI* midi, uint32_t frame_count)
+{
+	state->midi = midi;
+	state->frame_count = frame_count;
+	state->position = 0;
+}
+
+
+/** This function advances the read/write position in @c state to the next 
+    event and returns its timestamp, or the @c frame_count member of @c state
+    is there are no more events. */
+static double lv2midi_increment(LV2_MIDIState* state) {
+
+  if (state->position + sizeof(double) + sizeof(size_t) >= state->midi->size) {
+    state->position = state->midi->size;
+    return state->frame_count;
+  }
+  
+  state->position += sizeof(double);
+  size_t size = *(size_t*)(state->midi->data + state->position);
+  state->position += sizeof(size_t);
+  state->position += size;
+  
+  if (state->position >= state->midi->size)
+    return state->frame_count;
+  
+  return *(double*)(state->midi->data + state->position);
+}
+
+
+/** This function reads one event from the port associated with the @c state
+    parameter and writes its timestamp, size and a pointer to its data bytes
+    into the parameters @c timestamp, @c size and @c data, respectively.
+    It does not advance the read position in the MIDI data buffer, two 
+    subsequent calls to lv2midi_get_event() will read the same event.
+    
+    The function returns the timestamp for the read event, or the @c frame_count
+    member of @c state if there are no more events in the buffer. */
+static double lv2midi_get_event(LV2_MIDIState* state,
+                                double* timestamp, 
+                                uint32_t* size, 
+                                unsigned char** data) {
+  
+  if (state->position >= state->midi->size) {
+    state->position = state->midi->size;
+    *timestamp = state->frame_count;
+    *size = 0;
+    *data = NULL;
+    return *timestamp;
+  }
+  
+  *timestamp = *(double*)(state->midi->data + state->position);
+  *size = *(size_t*)(state->midi->data + state->position + sizeof(double));
+  *data = state->midi->data + state->position + 
+    sizeof(double) + sizeof(size_t);
+  return *timestamp;
+}
+
+
+/** This function writes one MIDI event to the port buffer associated with
+    @c state. It returns 0 when the event was written successfully to the
+    buffer, and -1 when there was not enough room. The read/write position
+    is advanced automatically. */
+static int lv2midi_put_event(LV2_MIDIState* state, 
+                             double timestamp,
+                             uint32_t size,
+                             const unsigned char* data) {
+
+  if (state->midi->capacity - state->midi->size < 
+      sizeof(double) + sizeof(size_t) + size)
+    return -1;
+  
+  *(double*)(state->midi->data + state->midi->size) = timestamp;
+  state->midi->size += sizeof(double);
+  *(size_t*)(state->midi->data + state->midi->size) = size;
+  state->midi->size += sizeof(size_t);
+  memcpy(state->midi->data + state->midi->size, data, size);
+  state->midi->size += size;
+  
+  ++state->midi->event_count;
+  
+  return 0;
+}
+
+
+#endif
+
diff --git a/examples/hosts/lv2-miditype.h b/examples/hosts/lv2-miditype.h
new file mode 100644
index 0000000..465d5d5
--- /dev/null
+++ b/examples/hosts/lv2-miditype.h
@@ -0,0 +1,170 @@
+/****************************************************************************
+    
+    lv2-miditype.h - header file for using MIDI in LV2 plugins
+    
+    Copyright (C) 2006  Lars Luthman <lars.luthman@gmail.com>
+    
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
+    
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307  USA
+
+****************************************************************************/
+
+#ifndef LV2_MIDITYPE_H
+#define LV2_MIDITYPE_H
+
+
+/** This data structure is used to contain the MIDI events for one run() 
+    cycle. The port buffer for a LV2 port that has the datatype 
+    <http://ll-plugins.nongnu.org/lv2/ext/miditype> should be a pointer 
+    to an instance of this struct. 
+
+    To store two Note On events on MIDI channel 0 in a buffer, with timestamps
+    12 and 35.5, you could use something like this code (assuming that 
+    midi_data is a variable of type LV2_MIDI):
+    @code
+    
+      size_t buffer_offset = 0;
+      *(double*)(midi_data->data + buffer_offset) = 12;
+      buffer_offset += sizeof(double);
+      *(size_t*)(midi_data->data + buffer_offset) = 3;
+      buffer_offset += sizeof(size_t);
+      midi_data->data[buffer_offset++] = 0x90;
+      midi_data->data[buffer_offset++] = 0x48;
+      midi_data->data[buffer_offset++] = 0x64;
+      ++midi_data->event_count;
+      
+      *(double*)(midi_data->data + buffer_offset) = 35.5;
+      buffer_offset += sizeof(double);
+      *(size_t*)(midi_data->data + buffer_offset) = 3;
+      buffer_offset += sizeof(size_t);
+      midi_data->data[buffer_offset++] = 0x90;
+      midi_data->data[buffer_offset++] = 0x55;
+      midi_data->data[buffer_offset++] = 0x64;
+      ++midi_data->event_count;
+      
+      midi_data->size = buffer_offset;
+      
+    @endcode
+    
+    This would be done by the host in the case of an input port, and by the
+    plugin in the case of an output port. Whoever is writing events to the
+    buffer must also take care not to exceed the capacity of the data buffer.
+    
+    To read events from a buffer, you could do something like this:
+    @code
+    
+      size_t buffer_offset = 0;
+      uint32_t i;
+      for (i = 0; i < midi_data->event_count; ++i) {
+        double timestamp = *(double*)(midi_data->data + buffer_offset);
+        buffer_offset += sizeof(double);
+        size_t size = *(size_t*)(midi_data->data + buffer_offset);
+        buffer_offset += sizeof(size_t);
+        do_something_with_event(timestamp, size, 
+                                midi_data->data + buffer_offset);
+        buffer_offset += size;
+      }
+        
+    @endcode
+*/
+typedef struct {
+
+  /** The number of MIDI events in the data buffer. 
+      INPUT PORTS: It's the host's responsibility to set this field to the
+      number of MIDI events contained in the data buffer before calling the
+      plugin's run() function. The plugin may not change this field.
+      OUTPUT PORTS: It's the plugin's responsibility to set this field to the
+      number of MIDI events it has stored in the data buffer before returning
+      from the run() function. Any initial value should be ignored by the
+      plugin.
+  */
+  uint32_t  event_count;
+  
+  /** The size of the data buffer in bytes. It is set by the host and may not
+      be changed by the plugin. The host is allowed to change this between
+      run() calls.
+  */
+  uint32_t  capacity;
+  
+  /** The size of the initial part of the data buffer that actually contains
+      data.
+      INPUT PORTS: It's the host's responsibility to set this field to the
+      number of bytes used by all MIDI events it has written to the buffer
+      (including timestamps and size fields) before calling the plugin's 
+      run() function. The plugin may not change this field.
+      OUTPUT PORTS: It's the plugin's responsibility to set this field to
+      the number of bytes used by all MIDI events it has written to the
+      buffer (including timestamps and size fields) before returning from
+      the run() function. Any initial value should be ignored by the plugin.
+  */
+  uint32_t  size;
+  
+  /** The data buffer that is used to store MIDI events. The events are packed
+      after each other, and the format of each event is as follows:
+      
+      First there is a timestamp, which should have the type "double",
+      i.e. have the same bit size as a double and the same bit layout as a 
+      double (whatever that is on the current platform). This timestamp gives 
+      the offset from the beginning of the current cycle, in frames, that 
+      the MIDI event occurs on. It must be strictly smaller than the 'nframes'
+      parameter to the current run() call. The MIDI events in the buffer must 
+      be ordered by their timestamp, e.g. an event with a timestamp of 123.23
+      must be stored after an event with a timestamp of 65.0.
+      
+      The second part of the event is a size field, which should have the type
+      "size_t" (as defined in the standard C header stddef.h). It should 
+      contain the size of the MIDI data for this event, i.e. the number of 
+      bytes used to store the actual MIDI event. The bytes used by the 
+      timestamp and the size field should not be counted.
+      
+      The third part of the event is the actual MIDI data. There are some
+      requirements that must be followed:
+      
+      * Running status is not allowed. Every event must have its own status 
+        byte.
+      * Note On events with velocity 0 are not allowed. These events are 
+        equivalent to Note Off in standard MIDI streams, but in order to make
+        plugins and hosts easier to write, as well as more efficient, only
+        proper Note Off events are allowed as Note Off. 
+      * "Realtime events" (status bytes 0xF8 to 0xFF) are allowed, but may not
+        occur inside other events like they are allowed to in hardware MIDI 
+        streams.
+      * All events must be fully contained in a single data buffer, i.e. events
+        may not "wrap around" by storing the first few bytes in one buffer and
+        then wait for the next run() call to store the rest of the event. If 
+        there isn't enough space in the current data buffer to store an event,
+        the event will either have to wait until next run() call, be ignored,
+        or compensated for in some more clever way.
+      * All events must be valid MIDI events. This means for example that
+        only the first byte in each event (the status byte) may have the eighth
+        bit set, that Note On and Note Off events are always 3 bytes long etc.
+        The MIDI writer (host or plugin) is responsible for writing valid MIDI
+        events to the buffer, and the MIDI reader (plugin or host) can assume
+        that all events are valid.
+        
+      On a platform where double is 8 bytes and size_t is 4 bytes, the data 
+      buffer layout for a 3-byte event followed by a 4-byte event may look 
+      something like this:
+      _______________________________________________________________
+      | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ...
+      |TIMESTAMP 1    |SIZE 1 |DATA |TIMESTAMP 2    |SIZE 2 |DATA   | ...
+      
+  */
+  unsigned char* data;
+
+} LV2_MIDI;
+
+
+
+#endif
diff --git a/examples/hosts/jack_host.c b/examples/hosts/simple_jack_host.c
index 655c939..655c939 100644
--- a/examples/hosts/jack_host.c
+++ b/examples/hosts/simple_jack_host.c
diff --git a/slv2/types.h b/slv2/types.h
index f93eea2..6bce16b 100644
--- a/slv2/types.h
+++ b/slv2/types.h
@@ -51,6 +51,9 @@ enum SLV2PortClass {
 /** lv2:float, IEEE-754 32-bit floating point number */
 #define SLV2_DATA_TYPE_FLOAT "http://lv2plug.in/ontology#float"
 
+/** MIDI buffer, as defined by lv2-miditype.h */
+#define SLV2_DATA_TYPE_MIDI "http://ll-plugins.nongnu.org/lv2/ext/miditype"
+
 
 #ifdef __cplusplus
 }