(cache)MIDI Out on Mac, simple code needed

MIDI Out on Mac, simple code needed

aj5555

Member #9,033

September 2007

I need to send a midi string out a MIDI interface on a Mac.
I need a simple standalone program that i can run, passing the hex bytes to send out the midi interface.
I haven't got a mac that i can write code upon, so im looking for someone that could write such a thing or be able to give me the information i'd need to persue this... any help would be greatly appreciated.

Thomas Harte

Member #33

April 2000

CoreAudio has a CoreMIDI component. I'm clueless about MIDI, does the following example that comes with the Developer Tools help?

1/*  Copyright © 2007 Apple Inc. All Rights Reserved.

Disclaimer: IMPORTANT:  This Apple software is supplied to you by 
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    following terms, and your use, installation, modification or
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    install, modify or redistribute this Apple software.
    
    In consideration of your agreement to abide by the following terms, and
    subject to these terms, Apple grants you a personal, non-exclusive
    license, under Apple's copyrights in this original Apple software (the
    "Apple Software"), to use, reproduce, modify and redistribute the Apple
    Software, with or without modifications, in source and/or binary forms;
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    without modifications, you must retain this notice and the following
    text and disclaimers in all such redistributions of the Apple Software. 
    Neither the name, trademarks, service marks or logos of Apple Inc. 
    may be used to endorse or promote products derived from the Apple
    Software without specific prior written permission from Apple.  Except
    as expressly stated in this notice, no other rights or licenses, express
    or implied, are granted by Apple herein, including but not limited to
    any patent rights that may be infringed by your derivative works or by
    other works in which the Apple Software may be incorporated.
    
    The Apple Software is provided by Apple on an "AS IS" basis.  APPLE
    MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
    THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
    FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
    OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
    
    IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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    INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
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    AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
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    POSSIBILITY OF SUCH DAMAGE.
40*/
41#include <CoreMIDI/MIDIServices.h>
42#include <CoreFoundation/CFRunLoop.h>
43#include <stdio.h>
44 
45// ___________________________________________________________________________________________
46// test program to echo MIDI In to Out
47// ___________________________________________________________________________________________
48 
49MIDIPortRef    gOutPort = NULL;
50MIDIEndpointRef  gDest = NULL;
51int        gChannel = 0;
52 
53static void  MyReadProc(const MIDIPacketList *pktlist, void *refCon, void *connRefCon)
54{
if (gOutPort != NULL && gDest != NULL) {
  MIDIPacket *packet = (MIDIPacket *)pktlist->packet;  // remove const (!)
  for (unsigned int j = 0; j < pktlist->numPackets; ++j) {
    for (int i = 0; i < packet->length; ++i) {
59//        printf("%02X ", packet->data<i>);
60 
      // rechannelize status bytes
      if (packet->data<i> >= 0x80 && packet->data<i> < 0xF0)
        packet->data<i> = (packet->data<i> & 0xF0) | gChannel;
    }
65 
66//      printf("\n");
    packet = MIDIPacketNext(packet);
  }
69 
  MIDISend(gOutPort, gDest, pktlist);
}
72}
73 
74int    main(int argc, char *argv[])
75{
if (argc >= 2) {
  // first argument, if present, is the MIDI channel number to echo to (1-16)
  sscanf(argv[1], "%d", &gChannel);
  if (gChannel < 1) gChannel = 1;
  else if (gChannel > 16) gChannel = 16;
  --gChannel;  // convert to 0-15
}
83 
// create client and ports
MIDIClientRef client = NULL;
MIDIClientCreate(CFSTR("MIDI Echo"), NULL, NULL, &client);

MIDIPortRef inPort = NULL;
MIDIInputPortCreate(client, CFSTR("Input port"), MyReadProc, NULL, &inPort);
MIDIOutputPortCreate(client, CFSTR("Output port"), &gOutPort);

// enumerate devices (not really related to purpose of the echo program
// but shows how to get information about devices)
int i, n;
CFStringRef pname, pmanuf, pmodel;
char name[64], manuf[64], model[64];

n = MIDIGetNumberOfDevices();
for (i = 0; i < n; ++i) {
  MIDIDeviceRef dev = MIDIGetDevice(i);
  
  MIDIObjectGetStringProperty(dev, kMIDIPropertyName, &pname);
  MIDIObjectGetStringProperty(dev, kMIDIPropertyManufacturer, &pmanuf);
  MIDIObjectGetStringProperty(dev, kMIDIPropertyModel, &pmodel);
  
  CFStringGetCString(pname, name, sizeof(name), 0);
  CFStringGetCString(pmanuf, manuf, sizeof(manuf), 0);
  CFStringGetCString(pmodel, model, sizeof(model), 0);
  CFRelease(pname);
  CFRelease(pmanuf);
  CFRelease(pmodel);
112 
  printf("name=%s, manuf=%s, model=%s\n", name, manuf, model);
}

// open connections from all sources
n = MIDIGetNumberOfSources();
printf("%d sources\n", n);
for (i = 0; i < n; ++i) {
  MIDIEndpointRef src = MIDIGetSource(i);
  MIDIPortConnectSource(inPort, src, NULL);
}

// find the first destination
n = MIDIGetNumberOfDestinations();
if (n > 0)
  gDest = MIDIGetDestination(0);
128 
if (gDest != NULL) {
  MIDIObjectGetStringProperty(gDest, kMIDIPropertyName, &pname);
  CFStringGetCString(pname, name, sizeof(name), 0);
  CFRelease(pname);
  printf("Echoing to channel %d of %s\n", gChannel + 1, name);
} else {
  printf("No MIDI destinations present\n");
}
137 
CFRunLoopRun();
// run until aborted with control-C
140 
return 0;
142}

I guess the relevant bits are:
MIDIOutputPortCreate(client, CFSTR("Output port"), &gOutPort);
To create an outgoing port,
gDest = MIDIGetDestination(0);
To pick a MIDI destination and the MIDIPacket and MIDIPacketList structs:

1/*!
@struct      MIDIPacket
@abstract    A collection of simultaneous MIDI events.

@field      timeStamp
          The time at which the events occurred, if receiving MIDI,
          or, if sending MIDI, the time at which the events are to
          be played.  Zero means "now."  The time stamp applies
          to the first MIDI byte in the packet.
@field      length    
          The number of valid MIDI bytes which follow, in data. (It
          may be larger than 256 bytes if the packet is dynamically
          allocated.)
@field      data
          A variable-length stream of MIDI messages.  Running status
          is not allowed.  In the case of system-exclusive
          messages, a packet may only contain a single message, or
          portion of one, with no other MIDI events.
          
          The MIDI messages in the packet must always be complete,
          except for system-exclusive.
22
          (This is declared to be 256 bytes in length so clients
          don't have to create custom data structures in simple
          situations.)
26*/
27struct MIDIPacket
28{
MIDITimeStamp    timeStamp;
UInt16        length;
Byte        data[256];
32};
33 
34typedef struct MIDIPacket      MIDIPacket;/*!
@struct      MIDIPacketList
@abstract    A list of MIDI events being received from, or being sent to,
        one endpoint.
@discussion
        The timestamps in the packet list must be in ascending order.
        
        Note that the packets in the list, while defined as an array, may not be
        accessed as an array, since they are variable-length.  To iterate through
        the packets in a packet list, use a loop such as:
44<pre>
45@textblock
MIDIPacket *packet = &packetList->packet[0];
for (int i = 0; i < packetList->numPackets; ++i) {
  ...
  packet = MIDIPacketNext(packet);
}
51@/textblock
52</pre>

@field      numPackets
          The number of MIDIPackets in the list.
@field      packet
          An open-ended array of variable-length MIDIPackets.
58*/
59struct MIDIPacketList
60{
UInt32        numPackets;  
MIDIPacket      packet[1];
63};

With those, just use MIDISend(MIDIPortRef port, MIDIEndpointRef dest, const MIDIPacketList *pktlist).

EDIT: if you can send me a meaningful hex byte list then I can try to knock up a commandline program for you. At the minute I don't really know enough about MIDI to be able to do anything on my own.

[My site [members.allegro.cc]] [Tetrominoes [members.allegro.cc]]

aj5555

Member #9,033

September 2007

thats awesome!
thanks for the info.
i dont have access to a Mac for another week.
I'd love to see a simple commandline app.

It needs to
1. connect to the midiout adapter
2. send the bytes from the commandline
3. exit

thats exactly what i need.

what i want to send is a Program Change message.
eg. bin-> 1100nnnn 0ppppppp Program change
in hex.. 0xCn 0x7F where n is channel, for my purposes it could be hard coded to channel 1 hex=0x00 so the complete message to send is 2 bytes.

uint8_t bytes_to_send[2];
bytes_to_send[0] = 0xC0;
bytes_to_send[0] = 0x7f & atoi(argv[1]);

reference: http://www.midi.org/about-midi/table1.shtml

does that make sense?

Thomas Harte

Member #33

April 2000

Cool — my main concern is that while it'll be easy enough to write something that compiles and superficially appears to be throwing bytes at an output device, I've not really enough knowledge to be able to test what I'm doing. But if you'll have a Mac in a week anyway, then I guess you'll be able to do that bit yourself. I'll do some hasty work on the Apple demo program and post to this thread or edit this post as necessary in the next couple of days...

EDIT:
Does this do what you want? Time will tell...

1#include <CoreServices/CoreServices.h> //for file stuff
2#include <AudioUnit/AudioUnit.h>
3#include <AudioToolbox/AudioToolbox.h> //for AUGraph
4#include <unistd.h> // used for usleep...
5 
6// This call creates the Graph and the Synth unit...
7OSStatus  CreateAUGraph (AUGraph &outGraph, AudioUnit &outSynth)
8{
9  OSStatus result;
10  //create the nodes of the graph
11  AUNode synthNode, limiterNode, outNode;
12  
13  ComponentDescription cd;
14  cd.componentManufacturer = kAudioUnitManufacturer_Apple;
15  cd.componentFlags = 0;
16  cd.componentFlagsMask = 0;
17 
18  require_noerr (result = NewAUGraph (&outGraph), home);
19 
20  cd.componentType = kAudioUnitType_MusicDevice;
21  cd.componentSubType = kAudioUnitSubType_DLSSynth;
22 
23  require_noerr (result = AUGraphAddNode (outGraph, &cd, &synthNode), home);
24 
25  cd.componentType = kAudioUnitType_Effect;
26  cd.componentSubType = kAudioUnitSubType_PeakLimiter;  
27 
28  require_noerr (result = AUGraphAddNode (outGraph, &cd, &limiterNode), home);
29 
30  cd.componentType = kAudioUnitType_Output;
31  cd.componentSubType = kAudioUnitSubType_DefaultOutput;  
32  require_noerr (result = AUGraphAddNode (outGraph, &cd, &outNode), home);
33  
34  require_noerr (result = AUGraphOpen (outGraph), home);
35  
36  require_noerr (result = AUGraphConnectNodeInput (outGraph, synthNode, 0, limiterNode, 0), home);
37  require_noerr (result = AUGraphConnectNodeInput (outGraph, limiterNode, 0, outNode, 0), home);
38  
39  // ok we're good to go - get the Synth Unit...
40  require_noerr (result = AUGraphNodeInfo(outGraph, synthNode, 0, &outSynth), home);
41 
42home:
43  return result;
44}
45 
46 
47// some MIDI constants:
48enum {
49  kMidiMessage_ControlChange     = 0xB,
50  kMidiMessage_ProgramChange     = 0xC,
51  kMidiMessage_BankMSBControl   = 0,
52  kMidiMessage_BankLSBControl    = 32,
53  kMidiMessage_NoteOn       = 0x9
54};
55 
56int main (int argc, const char * argv[]) {
57  AUGraph graph = 0;
58  AudioUnit synthUnit;
59  OSStatus result;
60  unsigned char *Buffer;
61  int BufferLen;
62 
63  if (argc < 2)
64  {
65    printf("No input!\n");
66    exit(1);
67  }
68  else
69  {
70    if(strlen(argv[1])&1)
71    {
72      printf("odd number of input characters\n");
73      exit(2);
74    }
75    Buffer = new unsigned char[strlen(argv[1]) / 2];
76    BufferLen = strlen(argv[1]) / 2;
77    
78    const char *Ptr = argv[1];
79    unsigned char *Target = Buffer;
80    while(*Ptr)
81    {
82      if(Ptr[0] < '0' || Ptr[0] > 'f') {printf("illegal character\n"); exit(3);}
83      if(Ptr[1] < '0' || Ptr[1] > 'f') {printf("illegal character\n"); exit(3);}
84      *Target = ((Ptr[0] - '0') << 4) | (Ptr[1] - '0');
85      Target++;
86      Ptr += 2;
87    }
88  }
89 
90  require_noerr (result = CreateAUGraph (graph, synthUnit), home);
91  // ok we're set up to go - initialize and start the graph
92  require_noerr (result = AUGraphInitialize (graph), home);
93 
94  CAShow (graph); // prints out the graph so we can see what it looks like...
95 
96  require_noerr (result = AUGraphStart (graph), home);
97 
98  MusicDeviceSysEx(synthUnit, Buffer, BufferLen);
99 
100  // ok we're done now
101 
102home:
103  if (graph) {
104    AUGraphStop (graph); // stop playback - AUGraphDispose will do that for us but just showing you what to do
105    DisposeAUGraph (graph);
106  }
107  return result;
108}

[My site [members.allegro.cc]] [Tetrominoes [members.allegro.cc]]