comparison data/fileio/MIDIFileWriter.cpp @ 301:73537d900d4b

* Add MIDI file export (closes FR#1643721)

+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    
+    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.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+
+/*
+   This is a modified version of a source file from the 
+   Rosegarden MIDI and audio sequencer and notation editor.
+   This file copyright 2000-2007 Richard Bown and Chris Cannam
+   and copyright 2007 QMUL.
+*/
+
+#include "MIDIFileWriter.h"
+
+#include "MIDIEvent.h"
+
+#include "model/NoteModel.h"
+
+#include "base/Pitch.h"
+
+#include <algorithm>
+#include <fstream>
+
+using std::ofstream;
+using std::string;
+using std::ios;
+
+using namespace MIDIConstants;
+
+MIDIFileWriter::MIDIFileWriter(QString path, NoteModel *model, float tempo) :
+    m_path(path),
+    m_model(model),
+    m_modelUsesHz(false),
+    m_tempo(tempo)
+{
+    if (model->getScaleUnits().toLower() == "hz") m_modelUsesHz = true;
+
+    if (!convert()) {
+        m_error = "Conversion from model to internal MIDI format failed";
+    }
+}
+
+MIDIFileWriter::~MIDIFileWriter()
+{
+    for (MIDIComposition::iterator i = m_midiComposition.begin();
+	 i != m_midiComposition.end(); ++i) {
+	
+	for (MIDITrack::iterator j = i->second.begin();
+	     j != i->second.end(); ++j) {
+	    delete *j;
+	}
+
+	i->second.clear();
+    }
+
+    m_midiComposition.clear();
+}
+
+bool
+MIDIFileWriter::isOK() const
+{
+    return m_error == "";
+}
+
+QString
+MIDIFileWriter::getError() const
+{
+    return m_error;
+}
+
+void
+MIDIFileWriter::write()
+{
+    writeComposition();
+}
+
+string
+MIDIFileWriter::intToMIDIBytes(int number) const
+{
+    MIDIByte upper;
+    MIDIByte lower;
+
+    upper = (number & 0xFF00) >> 8;
+    lower = (number & 0x00FF);
+
+    string rv;
+    rv += upper;
+    rv += lower;
+    return rv;
+}
+
+string
+MIDIFileWriter::longToMIDIBytes(unsigned long number) const
+{
+    MIDIByte upper1;
+    MIDIByte lower1;
+    MIDIByte upper2;
+    MIDIByte lower2;
+
+    upper1 = (number & 0xff000000) >> 24;
+    lower1 = (number & 0x00ff0000) >> 16;
+    upper2 = (number & 0x0000ff00) >> 8;
+    lower2 = (number & 0x000000ff);
+
+    string rv;
+    rv += upper1;
+    rv += lower1;
+    rv += upper2;
+    rv += lower2;
+    return rv;
+}
+
+// Turn a delta time into a MIDI time - overlapping into
+// a maximum of four bytes using the MSB as the carry on
+// flag.
+//
+string
+MIDIFileWriter::longToVarBuffer(unsigned long number) const
+{
+    string rv;
+
+    long inNumber = number;
+    long outNumber;
+
+    // get the lowest 7 bits of the number
+    outNumber = number & 0x7f;
+
+    // Shift and test and move the numbers
+    // on if we need them - setting the MSB
+    // as we go.
+    //
+    while ((inNumber >>= 7 ) > 0) {
+        outNumber <<= 8;
+        outNumber |= 0x80;
+        outNumber += (inNumber & 0x7f);
+    }
+
+    // Now move the converted number out onto the buffer
+    //
+    while (true) {
+        rv += (MIDIByte)(outNumber & 0xff);
+        if (outNumber & 0x80)
+            outNumber >>= 8;
+        else
+            break;
+    }
+
+    return rv;
+}
+
+bool
+MIDIFileWriter::writeHeader()
+{
+    *m_midiFile << MIDI_FILE_HEADER;
+
+    // Number of bytes in header
+    *m_midiFile << (MIDIByte) 0x00;
+    *m_midiFile << (MIDIByte) 0x00;
+    *m_midiFile << (MIDIByte) 0x00;
+    *m_midiFile << (MIDIByte) 0x06;
+
+    // File format
+    *m_midiFile << (MIDIByte) 0x00;
+    *m_midiFile << (MIDIByte) m_format;
+
+    *m_midiFile << intToMIDIBytes(m_numberOfTracks);
+
+    *m_midiFile << intToMIDIBytes(m_timingDivision);
+
+    return true;
+}
+
+bool
+MIDIFileWriter::writeTrack(int trackNumber)
+{
+    bool retOK = true;
+    MIDIByte eventCode = 0;
+    MIDITrack::iterator midiEvent;
+
+    // First we write into the trackBuffer, then write it out to the
+    // file with its accompanying length.
+    //
+    string trackBuffer;
+
+    for (midiEvent = m_midiComposition[trackNumber].begin();
+         midiEvent != m_midiComposition[trackNumber].end();
+         midiEvent++) {
+
+        // Write the time to the buffer in MIDI format
+        trackBuffer += longToVarBuffer((*midiEvent)->getTime());
+
+        if ((*midiEvent)->isMeta()) {
+            trackBuffer += MIDI_FILE_META_EVENT;
+            trackBuffer += (*midiEvent)->getMetaEventCode();
+
+            // Variable length number field
+            trackBuffer += longToVarBuffer((*midiEvent)->
+                                           getMetaMessage().length());
+
+            trackBuffer += (*midiEvent)->getMetaMessage();
+        } else {
+            // Send the normal event code (with encoded channel information)
+            if (((*midiEvent)->getEventCode() != eventCode) ||
+                ((*midiEvent)->getEventCode() == MIDI_SYSTEM_EXCLUSIVE)) {
+                trackBuffer += (*midiEvent)->getEventCode();
+                eventCode = (*midiEvent)->getEventCode();
+            }
+
+            // Send the relevant data
+            //
+            switch ((*midiEvent)->getMessageType()) {
+            case MIDI_NOTE_ON:
+            case MIDI_NOTE_OFF:
+            case MIDI_POLY_AFTERTOUCH:
+                trackBuffer += (*midiEvent)->getData1();
+                trackBuffer += (*midiEvent)->getData2();
+                break;
+
+            case MIDI_CTRL_CHANGE:
+                trackBuffer += (*midiEvent)->getData1();
+                trackBuffer += (*midiEvent)->getData2();
+                break;
+
+            case MIDI_PROG_CHANGE:
+                trackBuffer += (*midiEvent)->getData1();
+                break;
+
+            case MIDI_CHNL_AFTERTOUCH:
+                trackBuffer += (*midiEvent)->getData1();
+                break;
+
+            case MIDI_PITCH_BEND:
+                trackBuffer += (*midiEvent)->getData1();
+                trackBuffer += (*midiEvent)->getData2();
+                break;
+
+            case MIDI_SYSTEM_EXCLUSIVE:
+                // write out message length
+                trackBuffer +=
+                    longToVarBuffer((*midiEvent)->getMetaMessage().length());
+
+                // now the message
+                trackBuffer += (*midiEvent)->getMetaMessage();
+                break;
+
+            default:
+                break;
+            }
+        }
+    }
+
+    // Now we write the track - First the standard header..
+    //
+    *m_midiFile << MIDI_TRACK_HEADER;
+
+    // ..now the length of the buffer..
+    //
+    *m_midiFile << longToMIDIBytes((long)trackBuffer.length());
+
+    // ..then the buffer itself..
+    //
+    *m_midiFile << trackBuffer;
+
+    return retOK;
+}
+
+bool
+MIDIFileWriter::writeComposition()
+{
+    bool retOK = true;
+
+    m_midiFile =
+        new ofstream(m_path.toLocal8Bit().data(), ios::out | ios::binary);
+
+    if (!(*m_midiFile)) {
+        m_error = "Can't open file for writing.";
+        delete m_midiFile;
+        m_midiFile = 0;
+        return false;
+    }
+
+    if (!writeHeader()) {
+        retOK = false;
+    }
+
+    for (unsigned int i = 0; i < m_numberOfTracks; i++) {
+        if (!writeTrack(i)) {
+            retOK = false;
+        }
+    }
+
+    m_midiFile->close();
+    delete m_midiFile;
+    m_midiFile = 0;
+
+    if (!retOK) {
+        m_error = "MIDI file write failed";
+    }
+
+    return retOK;
+}
+
+bool
+MIDIFileWriter::convert()
+{
+    m_timingDivision = 480;
+    m_format = MIDI_SINGLE_TRACK_FILE;
+    m_numberOfTracks = 1;
+
+    int track = 0;
+    int midiChannel = 0;
+
+    MIDIEvent *event;
+
+    event = new MIDIEvent(0, MIDI_FILE_META_EVENT, MIDI_CUE_POINT,
+                          "Exported from Sonic Visualiser");
+    m_midiComposition[track].push_back(event);
+
+    event = new MIDIEvent(0, MIDI_FILE_META_EVENT, MIDI_CUE_POINT,
+                          "http://www.sonicvisualiser.org/");
+    m_midiComposition[track].push_back(event);
+
+    long tempoValue = long(60000000.0 / m_tempo + 0.01);
+    string tempoString;
+    tempoString += (MIDIByte)(tempoValue >> 16 & 0xFF);
+    tempoString += (MIDIByte)(tempoValue >> 8 & 0xFF);
+    tempoString += (MIDIByte)(tempoValue & 0xFF);
+
+    event = new MIDIEvent(0, MIDI_FILE_META_EVENT, MIDI_SET_TEMPO,
+                          tempoString);
+    m_midiComposition[track].push_back(event);
+
+    // Omit time signature
+
+    const NoteModel::PointList &notes =
+        static_cast<SparseModel<Note> *>(m_model)->getPoints();
+
+    for (NoteModel::PointList::const_iterator i = notes.begin();
+         i != notes.end(); ++i) {
+
+        long frame = i->frame;
+        float value = i->value;
+        size_t duration = i->duration;
+
+        int pitch;
+
+        if (m_modelUsesHz) {
+            pitch = Pitch::getPitchForFrequency(value);
+        } else {
+            pitch = lrintf(value);
+        }
+
+        if (pitch < 0) pitch = 0;
+        if (pitch > 127) pitch = 127;
+
+        // Convert frame to MIDI time
+
+        double seconds = double(frame) / double(m_model->getSampleRate());
+        double quarters = (seconds * m_tempo) / 60.0;
+        unsigned long midiTime = lrint(quarters * m_timingDivision);
+
+        // We don't support velocity in note models yet
+        int velocity = 100;
+
+        // Get the sounding time for the matching NOTE_OFF
+        seconds = double(frame + duration) / double(m_model->getSampleRate());
+        quarters = (seconds * m_tempo) / 60.0;
+        unsigned long endTime = lrint(quarters * m_timingDivision);
+
+        // At this point all the notes we insert have absolute times
+        // in the delta time fields.  We resolve these into delta
+        // times further down (can't do it until all the note offs are
+        // in place).
+
+        event = new MIDIEvent(midiTime,
+                              MIDI_NOTE_ON | midiChannel,
+                              pitch,
+                              velocity);
+        m_midiComposition[track].push_back(event);
+
+        event = new MIDIEvent(endTime,
+                              MIDI_NOTE_OFF | midiChannel,
+                              pitch,
+                              127); // loudest silence you can muster
+
+        m_midiComposition[track].push_back(event);
+    }
+    
+    // Now gnash through the MIDI events and turn the absolute times
+    // into delta times.
+    //
+    for (unsigned int i = 0; i < m_numberOfTracks; i++) {
+
+        unsigned long lastMidiTime = 0;
+
+        // First sort the track with the MIDIEvent comparator.  Use
+        // stable_sort so that events with equal times are maintained
+        // in their current order.
+        //
+        std::stable_sort(m_midiComposition[i].begin(),
+                         m_midiComposition[i].end(),
+                         MIDIEventCmp());
+
+        for (MIDITrack::iterator it = m_midiComposition[i].begin();
+             it != m_midiComposition[i].end(); it++) {
+            unsigned long deltaTime = (*it)->getTime() - lastMidiTime;
+            lastMidiTime = (*it)->getTime();
+            (*it)->setTime(deltaTime);
+        }
+
+        // Insert end of track event (delta time = 0)
+        //
+        event = new MIDIEvent(0, MIDI_FILE_META_EVENT,
+                              MIDI_END_OF_TRACK, "");
+
+        m_midiComposition[i].push_back(event);
+    }
+
+    return true;
+}
+