Re: Microtonal midi output

[Jacques Menu]

Hello Brahim,

What do you mean by ‘run this script’?

JM

> Le 9 mai 2021 à 15:58, brahim.pro <brahim.pro@protonmail.com> a écrit :
> 
> 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
> 
> 
>