Question

我有音符索引（每个八度有12个音符）与时间（以拍子为单位）数据。如何将这些数据转换为Midi文件？

Example Data:

time = [0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 9.0, 9.0, 9.0, 10.0, 10.0, 10.0, 11.0, 11.0]

notes  = [57.0, 59.0, 60.0, 62.0, 64.0, 65.0, 67.0, 57.0, 60.0, 64.0, 65.0, 62.0, 59.0, 64.0, 67.0]

乐器是钢琴。

另外，请注意同时存在多个音符。

谢谢。

Answer 1

我创建了一个程序，可以在读取Python之前将您的数据转换为C ++的MIDI文件。无论如何，我更喜欢C ++和Qt，因此本示例将drumstick-file library用于作业。免责声明：我是鼓槌的作者，以防万一有人抱怨垃圾邮件或自我宣传。这是代码：

smfbuilder.pro

TEMPLATE = app
CONFIG += c++11 console link_pkgconfig
packagesExist(drumstick-file) {
    message("using pkg-config")
    PKGCONFIG += drumstick-file
} else {
    message("using environment variables")
    INCLUDEPATH += $$(DRUMSTICKINCLUDES)
    LIBS += -L$$(DRUMSTICKLIBS) -ldrumstick-file
}
HEADERS += smfbuilder.h
SOURCES += smfbuilder.cpp

smfbuilder.h

#include <QObject>
#include <drumstick/qsmf.h>

class MidiEvent
{
public:
    long absTime;
    int  status;
    int  data1;
    int  data2;
};

class Sequence : public QList<MidiEvent>
{
public:
    virtual ~Sequence();
    void sort();
};

class SMFBuilder : public QObject
{
    Q_OBJECT
public:
    SMFBuilder();
    void run(QString fileName);
    void generate();

public slots:
    void errorHandler(const QString& errorStr);
    void trackHandler(int track);

private:
    drumstick::QSmf *m_engine;
    Sequence m_sequence;
};

smfbuilder.cpp

#include <QCoreApplication>
#include <QDebug>
#include <QTextCodec>
#include <drumstick/qsmf.h>
#include "smfbuilder.h"

static inline bool eventLessThan(const MidiEvent& s1, const MidiEvent& s2)
{
    return s1.absTime < s2.absTime;
}

void Sequence::sort()
{
    std::stable_sort(begin(), end(), eventLessThan);
}

Sequence::~Sequence()
{
    clear();
}

SMFBuilder::SMFBuilder() : QObject()
{
    m_engine = new drumstick::QSmf(this);
    m_engine->setTextCodec(QTextCodec::codecForName("UTF-8"));
    connect(m_engine, SIGNAL(signalSMFError(const QString&)), 
            this, SLOT(errorHandler(const QString&)));
    connect(m_engine, SIGNAL(signalSMFWriteTrack(int)), 
            this, SLOT(trackHandler(int)));
}

void SMFBuilder::errorHandler(const QString& errorStr)
{
    qWarning() << errorStr;
    exit(1);
}

void SMFBuilder::trackHandler(int )
{
    // meta events
    m_engine->writeBpmTempo(0, 100); // m.m.=100 (andante)
    m_engine->writeTimeSignature(0, 4, 2, 18, 8);  // ts = 4/4
    m_engine->writeKeySignature(0, 0, major_mode); // C major
    m_engine->writeMidiEvent(0, program_chng, 0, 0);  // grand piano
    // note events
    long last_time = 0;
    for(auto ev : m_sequence)
    {
        long delta = ev.absTime - last_time;
        last_time = ev.absTime;
        m_engine->writeMidiEvent(delta,  ev.status, 0, ev.data1, ev.data2);
    }
    // final event
    m_engine->writeMetaEvent(0, end_of_track); 
}

void SMFBuilder::run(QString fileName)
{
    m_engine->setDivision(120); // ticks per quarter note
    m_engine->setFileFormat(0); // single track
    m_engine->setTracks(1);
    m_engine->writeToFile(fileName);
}

void SMFBuilder::generate()
{
    QList<float> times = { 0.0,  1.0,  2.0,  3.0,  4.0,  5.0,  6.0,  9.0,  9.0,  9.0, 10.0, 10.0, 10.0, 11.0, 11.0};
    QList<float> notes = {57.0, 59.0, 60.0, 62.0, 64.0, 65.0, 67.0, 57.0, 60.0, 64.0, 65.0, 62.0, 59.0, 64.0, 67.0};
    long quarter_length = 120; // quarter note duration in ticks
    int velocityOn = 100; // forte

    for ( int i=0; i<times.length(); ++i) {
        long event_time = static_cast<long>(times[i] * quarter_length);
        int midi_note = static_cast<int>(notes[i]);
        // insert note on event
        MidiEvent noteOn;
        noteOn.absTime = event_time;
        noteOn.status = note_on;
        noteOn.data1 = midi_note;
        noteOn.data2 = velocityOn;
        m_sequence.append(noteOn);
        // insert note off event
        MidiEvent noteOff;
        noteOff.absTime = event_time + quarter_length;
        noteOff.status = note_off;
        noteOff.data1 = midi_note;
        noteOff.data2 = 0; // note off
        m_sequence.append(noteOff);
    }
    m_sequence.sort();
}

int main(int argc, char **argv)
{
    QCoreApplication app(argc, argv);
    SMFBuilder builder;
    builder.generate();
    builder.run("output.mid");
    return 0;
}

有关代码的一些注释：

您可以使用两种方式来配置鼓槌相关性。假设您使用的是Linux，请从Linux发行版中安装drumstick-devel软件包（或从源代码进行编译），并使用pkg-config管理依赖项，或者在QtCreator项目设置中定义环境变量DRUMSTICKINCLUDES和DRUMSTICKLIBS，或您的外壳。
MIDI文件就像一个乐谱。您的数据没有指定很多音乐参数，例如速度，音调，拍号...，我试图选择合理的值并提供适当的代码注释。
一般策略是在SMFBuilder :: generate（）中生成一系列midi事件，然后将其写入文件。

生成文件“ output.mid”之后，这是Rosegarden的表示形式：

如何将这些数据转换为MIDI文件？

1 个答案: