Re: Microtonal midi output

[brahim.pro]

Hello,

Thanks for the feedback.
Actually I cannot manage to run this script.
I tried this for example:

\version "2.22.0"

tuneMIDI =
#(define-music-function (scale music) (list? ly:music?)
    (let ((copy (ly:music-deep-copy music)))
      (for-some-music
        (lambda (m)
          (let ((pitch (ly:music-property m 'pitch)))
            (if (ly:pitch? pitch)
                (let* ((note-name (ly:pitch-notename pitch))
                       (alteration (ly:pitch-alteration pitch))
                       (offset (assoc-ref scale
                                          (cons note-name alteration))))
                  (if offset
                      (let* ((transpose-pitch (ly:make-pitch 0 0 offset))
                             (new-pitch (ly:pitch-transpose pitch
transpose-pitch)))
                        (ly:music-set-property! m 'pitch new-pitch)))))
            #f))
        copy)
      copy))

myNotes = \relative { a b c d e f gis aes a b c d e f gis aes a }

{ \myNotes }

\midi {
   \tempo 4 = 120
}

\score {
   \tuneMIDI
     #'(
        ; Lower F (index 3 in C major scale if 0 is C, no alteration) by
1/10 tone.
        ((3 . 0) . -1/2)
        ; Raise G# (index 4, sharp) by 1/10 tone.
        ((4 . 1/2) . 1/2)
        )
     \myNotes
   \midi { }
}

\score {
   \myNotes
   \midi { }
}

And I have two same midi files.
I tried also to make big detuning, but I just cannot hear that. I downloaded 
the last version of lilypond, and I still cannot manage to run this script.

I don't know what am I doing wrong?

Brahim


‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Sunday 9 May 2021 10:06, Jean Abou Samra <jean@abou-samra.fr> wrote:

> Le 08/05/2021 à 23:50, Lukas-Fabian Moser a écrit :
>
> > Hi Jean,
> >
> > > (let* ((tones (ly:pitch-tones pitch))
> > >                     (r (ly:moment-main
> > >                          (ly:moment-mod
> > >                            (ly:make-moment tones 0)
> > >                            (ly:make-moment 6 0))))
> >
> > ... using LilyPond's moment-arithmetic (number on the time axis) to
> > deal with non-integer tone counts (numbers on the pitch axis) seems to
> > me like a reasonable contender for an obfuscated Lily coding contest.
> > :-) But impressive it is.
>
> It is a well-known trick… See
> https://gitlab.com/lilypond/lilypond/-/issues/3139
>
> Guile's modulo and remainder functions only
> support integers, which is pitiful. Guile 2
> brought an improvement with euclidean-quotient
> and euclidean-remainder, which always yield a
> positive remainder, and support rationals as well
> as floats.
>
> > Maybe it's worth pointing out that your solution hardwires enharmonic
> > identification (if I'm not mistaken). Of course I don't know what the
> > OP intends to do, but in lots of real-life applications for re-tuning
> > it's worth keeping the difference between f-sharp and g-flat alive.
>
> Here is an enhanced version that stops enharmonic
> identification, and copies the music before processing
> it, to address Brahim's request.
>
> \version "2.22.0"
>
> tuneMIDI =
> #(define-music-function (scale music) (list? ly:music?)
>    (let ((copy (ly:music-deep-copy music)))
>      (for-some-music
>        (lambda (m)
>          (let ((pitch (ly:music-property m 'pitch)))
>            (if (ly:pitch? pitch)
>                (let* ((note-name (ly:pitch-notename pitch))
>                       (alteration (ly:pitch-alteration pitch))
>                       (offset (assoc-ref scale
>                                          (cons note-name alteration))))
>                  (if offset
>                      (let* ((transpose-pitch (ly:make-pitch 0 0 offset))
>                             (new-pitch (ly:pitch-transpose pitch
> transpose-pitch)))
>                        (ly:music-set-property! m 'pitch new-pitch)))))
>            #f))
>        copy)
>      copy))
>
> myNotes = \relative { a b c d e f gis aes a b c d e f gis aes a }
>
> { \myNotes }
>
> \midi {
>   \tempo 4 = 120
> }
>
> \score {
>   \tuneMIDI
>     #'(
>        ; Lower F (index 3 in C major scale if 0 is C, no alteration) by
> 1/10 tone.
>        ((3 . 0) . -1/10)
>        ; Raise G# (index 4, sharp) by 1/10 tone.
>        ((4 . 1/2) . 2/10)
>        )
>     \myNotes
>   \midi { }
> }
>
> \score {
>   \tuneMIDI
>     #'(((3 . 0) . -1/10))
>     \myNotes
>   \midi { }
> }
>
> > As Graham pointed out, LilyPond's habit of setting pitch bends before
> > a note and re-setting it immediately after a note whose alteration is
> > not in 1/2 * Z leads to strange effects with the release (or reverb)
> > of a note. This can be observed in examples involving rests between
> > re-tuned notes. I patched my LilyPond for this: Now it never
> > explicitly resets MIDI pitch bends, instead each and every note gets a
> > pitch-bend command. (Which would be crazy for most applications, but
> > is fine for my special needs involving lots of re-tuned notes.) I
> > didn't have time to find out how to make this user-configurable.
>
> An option would be to go create an issue at
> https://gitlab.com/lilypond/lilypond/-/issues
> and attach your patch there, noting that it
> is a work-in-progress and configurability should
> be added. That way, someone might pick it up.
>
> > -   I'm already looking forward to Graham's solution to this problem
> >     (post-processing the MIDI files using MTS messages.
> >
>
> I haven't tried it (understanding of MIDI is above
> my pay grade), but it shoud certainly yield better
> results.
>
> Cheers,
> Jean