Midi output with highlighted voices

[Jonathan Scholbach]

Dear Ponders,

I have a feature wish, and I hope this is the right channel to utter it:

I typeset choir pieces and in this field it is a big advantage of
LilyPond that producing MIDI files with highlighted voices for each
single voice is possible. Today I do this by defining a new book for
each voice and by "highlighting" the respective voice - by increasing
her volume and assigning her a distinct midiInstrument - see the
attached MWE. The result is good and very usable for choirs to improve
the individual practicing at home.

But the input is ugly. The MWE works with only 2 voices and yet has a
lot of repetitive code. Imagine a piece with 8 voices! The MIDI output
for 8 highlighted voices would need hundreds of highly repetitive lines
of LilyPond code. I wish there was a feature to produce the output with
one line of code in the \midi{}-section of the pdf producing \score.
LilyPond would have to loop over the voices in the score and produce a
book as described in the MWE.

I have tried to understand Scheme multiple times but I didn't make it
yet. That's why I would be thankful if someone could write the Scheme
function to achieve that. I think many typesetters of choir music would
appreciate an easy way to produce the MIDI as described. (Actually,
there are some guys around who do that with some other programmes, see
[1], [2]). I believe most typesetters don't know the way how to do it
with LilyPond today - that's why I think this would be a great benefit
for the community.

Kind regards,
Jonathan

[1] http://www.learnchoralmusic.co.uk/

[2] http://www.choraltech.us/midilibrary.htm

midi with highlighted voices.ly
Description: Text Data