Re: midi performance hacking

[Michael Welsh Duggan]

Mats Bengtsson <address@hidden> writes:

> I don't really see why you include a new context, at least
> not as long as you don't add the corresponding type of context
> for the paper output.

I accidentally neglected to change the paper output accordingly.  I
should have added 

        \context {
            \ScoreContext
            \accepts StaffTrack
        }

to the paper block.  The new context is necessary because at one
point I want a groups of staves to be aggregated into one midi track,
and there is a separate staff which I want on a separate track.

> So far, people who have tried to use the MIDI output for anything
> else then plain "proof reading" (which really is the level of ambition
> for the current MIDI support), have typically needed to do a separate
> \score{} declaration for the MIDI. If your intention is to make easier
> to affect the MIDI output while keeping a single \score{} for both the
> MIDI and paper output, I see the point. 

I do think that one score should be sufficient.  

> However, then I would not solve it by adding more types of
> contexts. Rather, it should be done with properties. 

I agree.  I don't want to add more contexts so much as a way of
saying (for example), "In this particular staff I want you to ignore
the fact that the staff context is a Staff_performer, and pass the
events up the context stack to the next accepting Staff_performer."

> One possibility in current LilyPond that may be useful is the \tag
> feature, see
> http://lilypond.org/doc/v2.2/Documentation/user/out-www/lilypond/Different-editions-from-one-source.html#Different%20editions%20from%20one%20source

There are some things that could be hacked with tags, but the ones I
can think of would still require seperate scores.  I would like to
make as much of the midi output "just work" as much as possible,
because I see that as the LilyPond way.

> Regarding your previous email on restructuring the MIDI support, I hope
> you can also solve the following bug report:
> http://mail.gnu.org/archive/html/bug-lilypond/2003-10/msg00069.html

I would like to fix that one as well, and should be pretty easy to
do.  I think I will look at this next.  What I have read
(<URL:http://www.borg.com/~jglatt/> is a good source) seems to
indicate that tempo should be in track zero.

<URL:http://www.borg.com/~jglatt/tech/midifile/tempo.htm> reads:

In format 1, the very first MTrk should consist of only the tempo (and
time signature) events so that it could be read by some device capable
of generating a "tempo map". It is best not to place MIDI events in
this MTrk.

> Michael Welsh Duggan wrote:
>> The included file demonstrates one of the things I want to do on a
>> general basis: to be able to determine at what context levels midi
>> tracks are aggregated upon.
>> It would be nice if this were less tortuous, and didn't require
>> making a new type of Staff.  Can anyone think of a good way to do
>> this?  (Doesn't necessarily have to be possible in current LilyPond.
>> Something which makes good sense which could be implemented would be
>> just fine.  Of course, I am volunteering to help with
>> implementation.)
>> \include "english.ly"
>> \version "2.2.3"
>> \score {
>>     <<
>>      \new StaffTrack \notes a'1
>>      \new PianoStaff         <<
>>          \new Staff \notes a'
>>          \new Staff \notes {\clef bass a}
>>      >>
>>     >>
>>     \paper { raggedright = ##t }
>>     \midi {
>>      \context {
>>          \ScoreContext
>>          \accepts StaffTrack
>>      }
>>      \context {
>>          \name StaffTrack
>>          \accepts Voice
>>          \type "Staff_performer"
>>          \consists "Key_performer"
>>          \consists "Tempo_performer"
>>          \consists "Time_signature_performer"
>>      }
>>      \context {
>>          \StaffContext
>>          \type "Performer_group_performer"
>>          \remove "Key_performer"
>>          \remove "Tempo_performer"
>>          \remove "Time_signature_performer"
>>      }
>>      \context {
>>          \PianoStaffContext
>>          \type "Staff_performer"
>>          \consists "Key_performer"
>>          \consists "Tempo_performer"
>>          \consists "Time_signature_performer"
>>      }
>>     }
>> } 

-- 
Michael Welsh Duggan
(address@hidden)