如何将 sysex 数据添加到 MusicTrack？ （音频工具箱）

Posted 2023-02-16

【中文标题】如何将 sysex 数据添加到 MusicTrack？ （音频工具箱）

【英文标题】：How to add sysex data to MusicTrack? (AudioToolbox)

【发布时间】：2014-05-07 13:58:08

【问题描述】：

我正在尝试用二十一点等编写我的小型 midi 音序器，但坚持将 sysex 数据写入 MusicTrack。我使用以下代码插入 sysex 事件

// ---- Some code here --- //

PatternData pattern =  sizeof(PatternData), i, signature.numerator, signature.denominator ;
CABarBeatTime beattime = CABarBeatTime((i * signature.numerator * signature.denominator) + 1, 1, 0, SUBBEAT_DIVISOR_DEFAULT);
// Convert beattime to timestamp 
if ((MusicSequenceBarBeatTimeToBeats(sequence, &beattime, &timestamp)) != noErr) 

return status; 
 
// Add event 
if ((status = MusicTrackNewMIDIRawDataEvent(track, timestamp, (MIDIRawData*)&pattern)) != noErr) 
 
return status; 


// ---- Some code here --- //

PatternData 是

typedef struct PatternData 
 
UInt32 length; // Struct length 
UInt8 index; // Pattern index 
UInt8 bars; // Number of bars in patten 
UInt8 beats; // Number of beats in pattern 
 PatternData;

我做错了什么，因为在调用 MusicSequenceFileCreate 后我得到了损坏的文件。 有人有如何将 sysex 数据添加到音乐曲目的示例吗？

【问题讨论】：

你为什么不使用MIDIRawData 结构？

@CL。使用 MIDIRawData 我得到了相同的结果。此外，我想使用我自己的数据结构。我将我的结构转换为 MIDIRawData。 （在lists.apple.com/archives/coreaudio-api/2006/Feb/msg00147.html 发现了这种模式的提及）

您必须将数据包装到 SysEx 消息中，并且必须将该消息包装到与 MIDIRawData 结构具有相同布局的结构中。无论如何，对于 SysEx，你的 manufacturer ID 是什么？

@CL。我没有制造商标识符。在我看来，sysex 是在 midi 文件中存储自定义数据的好主意。你能给我一个例子，如何将 sysex 和 sysex 消息中的结构包装到 MIDIRawData 中吗？

如果您没有购买ID，则无法使用SysEx消息。

【参考方案1】：

好的。我找到了正确的方法，就是这样：

    UInt8 data[] =  0xF0, manufacturerId, databyte1, databyte2, databyte3, 0xF7 ;
    MIDIRawData raw;
    memcpy(raw.data, data, 0, sizeof(data));
    raw.length = sizeof(data);

    if ((status = MusicTrackNewMIDIRawDataEvent(track, timestamp, &raw)) != noErr)
    
        return status;
    

【讨论】：

您不能使用memccpy，因为您的数据可能包含零字节。 raw.data 的大小只有一个字节；你有一个缓冲区溢出并且正在破坏你的堆栈。

在其他情况下这是真的（几乎总是），但这段代码就像魅力一样。使用 MidiKit 应用程序或使用我的测试应用程序成功打开保存的文件。

但是当你说数据中的零字节时你是对的。我应该使用 memcpy 而不是 memccpy。

【参考方案2】：

这里是一个例子，如何在一个 MIDI 轨道中录制正常的 MIDI 和 SYSEX 消息，并将它们保存在共享 iTunes 文件夹中的一个 MIDI 文件中（在 .plist 中将“应用程序支持 iTunes 文件共享”设置为“YES”）： 见代码中的“calloc”！

#import "ViewController.h"
#import <CoreMIDI/MIDIServices.h>
#import <CoreMIDI/CoreMIDI.h>
#import "AppDelegate.h"
#include <sys/time.h>
#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>
#import <AVFoundation/AVFoundation.h>

@interface ViewController ()

@end

@implementation ViewController

@synthesize SYSEX_8;

long secTempA = 0;
float secTempB = 0;
long secStartA = 0;
float secStartB = 0;
MusicTimeStamp timeStamp = 0;
MusicSequence recordSequence;
MusicTrack recordTrack;
MusicTimeStamp lenRec = 0;
MIDINoteMessage noteMessage;
MusicTrack track;
NSString *fileNameForSave = @"";
NSString *midiFileWritePath = @"";
NSString *documentsDirectoryPath = @"";
UIAlertView *infoStore;
UIAlertView *infoStoreError;
MIDIRawData *sysexData;

- (void)viewDidLoad 
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    // Get documents Directory
    // (don't forget the ".plist" entry "Application supports iTunes file sharing YES"
    NSArray *pathDocDir = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    documentsDirectoryPath = [pathDocDir objectAtIndex:0];



- (void)didReceiveMemoryWarning 
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.


- (IBAction)SYSEX_8_touchdown:(id)sender  
    NewMusicSequence(&recordSequence);
    MusicSequenceNewTrack(recordSequence, &recordTrack);
    MusicSequenceSetSequenceType(recordSequence, kMusicSequenceType_Beats);

    timeStamp = 0;
    struct timeval time;
    gettimeofday(&time, NULL);
    secStartA = time.tv_sec;
    secStartB = time.tv_usec * 0.000001;

    noteMessage.channel = 0x90; // Note ON 
    noteMessage.note = 0x3C;
    noteMessage.velocity = 0x7F;
    MusicTrackNewMIDINoteEvent(recordTrack, timeStamp, &noteMessage);
    NSLog(@"%02x %02x %02x", 0x90, 0x3C, 0x7F);

    usleep(10000);

    gettimeofday(&time, NULL);
    secTempA = time.tv_sec;
    secTempB = time.tv_usec * 0.000001;
    secTempA = secTempA - secStartA;
    secTempB = secTempB - secStartB;
    timeStamp = (secTempA + secTempB) * 2;

    noteMessage.channel = 0x90; // Note OFF
    noteMessage.note = 0x3C;
    noteMessage.velocity = 0x00;
    MusicTrackNewMIDINoteEvent(recordTrack, timeStamp, &noteMessage);
    NSLog(@"%02x %02x %02x", 0x90, 0x3C, 0x00);

    usleep(100000);

    gettimeofday(&time, NULL);
    secTempA = time.tv_sec;
    secTempB = time.tv_usec * 0.000001;
    secTempA = secTempA - secStartA;
    secTempB = secTempB - secStartB;
    timeStamp = (secTempA + secTempB) * 2;

    Byte datatest[8];
    UInt32 theSize = offsetof(MIDIRawData, data[0]) + (sizeof(UInt8) * sizeof(datatest));
    sysexData = (MIDIRawData *)calloc(1, theSize);
    sysexData->length = sizeof(datatest);

    datatest[0] = 0xF0;  // Start SYSEX
    datatest[1] = 0x26;
    datatest[2] = 0x79;
    datatest[3] = 0x0E;
    datatest[4] = 0x00;
    datatest[5] = 0x00;
    datatest[6] = 0x00;
    datatest[7] = 0xF7;  // End SYSEX

    for (int j = 0; j < sizeof(datatest); j++) 
        sysexData->data[j] = datatest[j];
        NSLog(@"%02x", sysexData->data[j]);
    

    int status;
    if ((status = MusicTrackNewMIDIRawDataEvent(recordTrack, timeStamp, sysexData) != noErr)) 
        NSLog(@"error %i", status);
    
    else 
        [self stopRecording];
    


- (void) stopRecording 

    CAShow(recordSequence);  // To show all MIDI events !!!

    UInt32 sz = sizeof(MusicTimeStamp);
    lenRec = 0;
    MusicSequenceGetIndTrack(recordSequence, 0, &track);
    MusicTrackGetProperty(track, kSequenceTrackProperty_TrackLength, &lenRec, &sz);

    if (lenRec > 0.1)
        NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss +zzzz"];
        NSDate *startDate = [NSDate date];

        NSTimeZone *zone = [NSTimeZone systemTimeZone];
        NSInteger interval = [zone secondsFromGMTForDate:startDate];
        startDate = [startDate dateByAddingTimeInterval:interval];
        //    NSLog(@"Date: %@", startDate);

        NSString *strDate = [[NSString alloc] initWithFormat:@"%@", startDate];
        NSArray *arr = [strDate componentsSeparatedByString:@" "];
        NSString *str;
        str = [arr objectAtIndex:0];
        NSArray *arr_date = [str componentsSeparatedByString:@"-"];

        int year = [[arr_date objectAtIndex:0] intValue];
        int month = [[arr_date objectAtIndex:1] intValue];
        int day = [[arr_date objectAtIndex:2] intValue];

        str = [arr objectAtIndex:1];
        NSArray *arr_time = [str componentsSeparatedByString:@":"];

        int hours = [[arr_time objectAtIndex:0] intValue];
        int minutes = [[arr_time objectAtIndex:1] intValue];
        int seconds = [[arr_time objectAtIndex:2] intValue];

        fileNameForSave = [NSString stringWithFormat:@"%@_%04d%02d%02d_%02d%02d%02d%@", @"$Record", year, month, day, hours, minutes, seconds, @".mid"];
        midiFileWritePath = [documentsDirectoryPath stringByAppendingPathComponent:fileNameForSave];

        infoStore = [[UIAlertView alloc]initWithTitle: @"Save as MIDI file ?"
                                              message: [NSString stringWithFormat:@"\n%@", fileNameForSave]
                                             delegate: self
                                    cancelButtonTitle: @"YES"
                                    otherButtonTitles: @"NO",nil];
        [infoStore show];  // rest siehe unten !!!!!
    
    else 
        MusicSequenceDisposeTrack(recordSequence, track);
        DisposeMusicSequence(recordSequence);
    



- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(int)buttonIndex 
    // deletion code here
    if (alertView == infoStore) 
        if (buttonIndex == 0) 
            NSURL *midiURL = [NSURL fileURLWithPath:midiFileWritePath];
            OSStatus status = 0;
            status = MusicSequenceFileCreate(recordSequence, (__bridge CFURLRef)(midiURL), kMusicSequenceFile_MIDIType, kMusicSequenceFileFlags_EraseFile, 0);
            if (status != noErr) 
                infoStoreError = [[UIAlertView alloc]initWithTitle: @"Information"
                                                           message: [NSString stringWithFormat:@"\nError storing MIDI file in: %@", documentsDirectoryPath]
                                                          delegate: self
                                                 cancelButtonTitle: nil
                                                 otherButtonTitles:@"OK",nil];
                [infoStoreError show];
            
        
        MusicSequenceDisposeTrack(recordSequence, track);
        DisposeMusicSequence(recordSequence);
    



@end