Re: Q: Irregular alternate repeats and MIDI

[H. S. Teoh]

On Tue, Aug 11, 2020 at 07:29:33AM -0700, Flaming Hakama by Elaine wrote:
>      ---------- Forwarded message ----------
>      From: Michael Gerdau <[1]mgd@qata.de>
>      To: Lilypond User <[2]lilypond-user@gnu.org>
>      Date: Sat, 18 Jul 2020 07:57:23 +0200 (CEST)
>      Subject: Q: Irregular alternate repeats and MIDI
>      Hi List,
> 
>      I have a score with repeats and irregular alternate endings. I
>      can neatly engrave that but I don't seem to be able to produce
>      correct MIDI w/o manually arranging all segments.
[...]

I've struggled with this before, and eventually I just gave up and stuck
the segments in variables, and manually arrange them. Lilypond is
primarily a typesetting program, and even though we've made advances in
MIDI generation over the years it's still not quite there. Because of
this I usually use two scores, one just for layout, and one just for
midi, and the music content is stored in variables to be incorporated
into either score as necessary.


>    Not exactly what you asked for, but one possible approach is to use
>    tags.
> 
>    Tags allow for conditional use of material.
> 
>    In this case, you would add a tag that is specific to MIDI and put
>    the repetitions in a similar way you did in the "manual" version.
> 
>    Then, have two different scores, one for PDF and one for MIDI,
>    which use different tags.

Definitely recommend this approach.  This is what I usually do:

        global = {
                \time 3/4
                \tempo 4 = 100
                s1*12
                \tempo 4 = 120
                s1*12
                ...
        }

        voiceA = {
                ... % music here
                \tag #'layout {
                        % stuff here only for layout, not for MIDI
                }
                ... % more music
        }
        voiceB = {
                ... % music here
                \tag #'midi {
                        % stuff here only for MIDI, not for layout
                }
                ... % more music
        }
        ...

        % This score is only for layout
        \score {
                \removeWithTag #'midi
                <<
                        \new Staff {
                                % Repeats only present in layout score
                                \repeat volta {
                                        \voiceA
                                }
                                ...
                        }
                        \new Staff {
                                ... % ditto
                                \voiceB
                        }
                >>
                \layout {}
        }

        % This score only for MIDI
        \score {
                \removeWithTag #'layout
                <<
                        \new Staff {
                                % Manually sequence repeats if needed
                                \repeat unfold {
                                        % Apply global events to every
                                        % staff For more reliable MIDI
                                        % generation
                                        << \global \voiceA >>
                                }
                        }
                        \new Staff <<
                                ... % ditto
                                \global \voiceB
                        >>
                >>
                \midi {}
        }


T

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