Re: Lily 2.7.7 and MIDI

[Michael Welsh Duggan]

Erik Sandberg <address@hidden> writes:

> On Wednesday 24 August 2005 08.59, Daniel Johnson wrote:
>> Hello all --
>>
>> I know that MIDI output was broken under 2.7.5 (and 2.7.6?).  Is it
>> functional under 2.7.7?  I'm running the 2.7 series now and I'd prefer
>> not to have to do a parallel installation of 2.6 just for the sake of MIDI.
>
> A quick test shows that it seems to work with latest CVS, but that the output 
> is pretty broken. ({c4 d e f} => {c4*1/384 d e f} )
>
> You can subscribe to the info-lilypond list to see announcements for new 2.7 
> versions, if you're lucky it will be mentioned when midi is fixed.
>
> I'm afraid the suggested solution to your problem otherwise is to use a 
> parallel 2.6 installation.

I've been looking into this.  The problem is twofold: 

1) Time offsets devolve into "1"s (instead of "384"s).  This is due to
   the addition of Rational::operator bool().  A rational offset is
   being converted to an int in Midi_event::to_string().  In the past,
   this used numeric promotion to call Rational::operator double().
   However, since the addition of Rational::operator bool(), it used
   that instead.  (C++ still has some int/bool confusion.)  The simple
   fix is to add a Rational::operator int().  A patch is included.

2) Audio_tempo objects are not being added to the Audio_staffs.  This
   results in the tempo not being passed to the midi file.  In the
   past, it was added by Staff_performer::play_element(Audio_element).  
   Now, however, Staff_performer does not have a specialized
   play_element function, and Lilypond relies upon
   Staff_performer::acknowledge_audio_element(Audio_element_info) to
   add Audio_items to the Audio_staffs.  This never gets called for
   the track name or the tempo because these elements are generated by
   Staff_performer::initialize(), and
   Performer_group::acknowledge_audio_elements() doesn't pass the
   elements to the origin Performer.

   I don't know the right way to fix this (although I can come up with
   plenty of gross hacks which would work), so I pass the question of
   the correct way to fix this to the developers.

lilypond-midi-patch.diff
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-- 
Michael Welsh Duggan
(address@hidden)