The issue of missing audio effects.

[Dahurica]

Hello,

The currently generated MIDI file has incorrect durations for grace notes, and there are no playback effects for mordents, trills, turns, and inverted turns. Could you please advise on where I can make changes to include the logic for these elements in the generated MIDI?

Thank you!

Here is my XML:

```javascript 60 0 4 4 2 G 2 F 4 Grave 1 1 D 5 60 1 quarter up 1 C 5 60 1 quarter up 1 C 5 60 1 quarter up 1 C 5 60 1 quarter up 1 1 240 C 5 2 32nd down 1 begin begin forward hook C 5 2 16th down 1 continue end E 4 2 eighth down 1 end E 4 60 2 quarter down 1 E 4 60 2 quarter down 1 E 4 2 32nd down 1 begin begin begin E 4 2 32nd down 1 end end end E 4 60 2 quarter down 1 E 4 2 eighth down 1 F 4 60 2 quarter down 1 240 240 5 2 light-light Largo 1

1 1 C 5 120 1 whole 2 1 1 3 A 4 120 1 whole 2 1 1 3 1 240 E 3 120 5 whole 2 1 2 1 C 3 120 5 whole 2 1 2 1 light-heavy heavy-light Lento 1 1 B 4 120 1 half down 1 3 G 4 120 1 half up 1 3 240 E 3 120 5 half down 2 2 D 3 120 5 half down 2 2 ```

In the first measure, there is an issue with the grace note playback. At standard tempo, it might be inaudible, making it seem like there is no sound

[craigsapp]

A request for mordents, trills, turn, etc for MIDI export has an issue already: https://github.com/rism-digital/verovio/issues/1928

Algorithms that take tempo (and note score-based durations) are needed in order to realize mordents, trills, and turns (and to some extent for grace notes). If there are published algorithms for generating ornaments, this it is more likely that these ornaments will be added to verovio. I.e., at tempo 100, how should auxiliary notes for a mordent on a quarter note be realized, at a tempo of 180 on an 8th note?, etc. Providing such algorithms would make it more likely to be implement in verovio.

Do you mean where in the C++ code to add for a PR? @lpugin could answer that. Basically in src/midifunctor.cpp.

There have been other samplers of ornaments to realize in MIDI in the past week: https://github.com/rism-digital/verovio/issues/3754 https://github.com/rism-digital/verovio/issues/3770

The MusicXML excerpt is nice, but preferably a complete file is desired (that can be loaded into verovio, since an excerpt cannot be loaded). Otherwise, nothing can be down with the excerpt, such as check to see if there is a problem in the MusicXML import as compared to grace notes in the MEI form of the data.

grace notes do note have a duration, so it cannot be wrong :-)

        <grace/>
        <pitch>
          <step>C</step>
          <octave>5</octave>
          </pitch>
        <voice>2</voice>
        <type>32nd</type>
        <stem>down</stem>
        <staff>1</staff>
        <beam number="1">begin</beam>
        <beam number="2">begin</beam>
        <beam number="3">forward hook</beam>
        </note>

GenerateMIDIFunctor::GenerateGraceNoteMIDI() in src/midifunctor.cpp is used to add grace notes to MIDI:

void GenerateMIDIFunctor::GenerateGraceNoteMIDI(
    const Note *refNote, double startTime, int tpq, int channel, int velocity)
{
    double graceNoteDur = 0.0;
    if (m_accentedGraceNote && !m_graceNotes.empty()) {
        const double totalDur = refNote->GetScoreTimeDuration() / 2.0;
        this->DeferMIDINote(refNote, totalDur, true);
        graceNoteDur = totalDur / m_graceNotes.size();
    }
    else {
        graceNoteDur = UNACC_GRACENOTE_DUR * m_currentTempo / 60000.0;
        const double totalDur = graceNoteDur * m_graceNotes.size();
        if (startTime >= totalDur) {
            startTime -= totalDur;
        }
        else {
            this->DeferMIDINote(refNote, totalDur, true);
        }
    }

    for (const MIDIChord &chord : m_graceNotes) {
        const double stopTime = startTime + graceNoteDur;
        for (int pitch : chord.pitches) {
            m_midiFile->addNoteOn(m_midiTrack, startTime * tpq, channel, pitch, velocity);
            m_midiFile->addNoteOff(m_midiTrack, stopTime * tpq, channel, pitch);
        }
        startTime = stopTime;
    }
}

Line 75 of include/vrv/vrv.h has the definition of the duration of a grace note which seems to be 27 milliseconds:

 #define UNACC_GRACENOTE_DUR 27 // in milliseconds

[craigsapp]

Note that there are two types of grace notes in MEI: accacciaturas rendered with slashes and appoggiaturas redered without slashes:

Click to view MEI data for above example.

```xml 作曲 / 编排 2024-09-14 Verovio

Transcoded from MusicXML

钢琴 Pno.

Grave Largo p

```

All grace notes except the third one are @grace="acc", with the third one being @grace="unacc"`

The third one in MusicXML:

      <note>
        <grace slash="yes"/>
        <pitch>
          <step>E</step>
          <octave>4</octave>
          </pitch>
        <voice>2</voice>
        <type>eighth</type>
        <stem>down</stem>
        <staff>1</staff>
        <beam number="1">end</beam>
        </note>
      <note>

With the <grace slash="yes"/> being converted to @grace="unacc" (as expected).

The others are <grace/> being converted to @grace="unacc" (as expected).

Behavior of the last three grace notes are expected according to how these are treated in verovio currently. (first two are not, but this might be related to the third grace note being @grace="unacc", and the acc and unacc types cannot really be mixed, particularly when the unacc one follow an acc one).

Preferrably `@grace="acc" should not steal 1/2 of the duration of the following note, but rather steal the duration according to the visual duration of those grace notes.

The playback of the 4th and 5th grace notes is related to verovio rendering converting them to 16th notes rather than as 32nd notes.

I do hear the first D5 note in Verovio MIDI output and playback with WildWebMidi (WildWebMidi has a problem with overlapping notes on the same pitch, but that problem does not occur in this example). In Musescore playback, I do not hear starting D6 note (but that note is exported in the MIDI output from Musescore).

The timemap positions of the grace notes seems to be incorrect. Playing this example in VHV has all of the grace notes for the measure highlighting on beat one. The playback is correct but the highlighting is wrong (possibly related to VHV, but more likely in the timemap). There was a problem in the past with the grace notes playing improperly at the start of a measure when they were in secondary(?) layers, but this was fixed, and possibly the same fix is needed for the timemap).

[craigsapp]

Related to the duplication of the tempo markings in the verovio MIDI output, this test MEI file does not have a problem:

Click to view MEI data for above example

```xml