Re: Going back in MIDI time error: disappeared?

[Colin Hall]

Federico Bruni writes:

> Il 06/01/2013 17:07, Trevor Daniels ha scritto:
>>
>> Federico, you wrote Sunday, January 06, 2013 3:28 PM
>> Subject: Going back in MIDI time error: disappeared?
>>
>>
>>> NR 1.2.6, Grace notes, section Known problems:
>>>
>>> """
>>> Each grace note in MIDI output has a length of 1/4 of its actual
>>> duration. If the combined length of the grace notes is greater than the
>>> length of the preceding note a “Going back in MIDI time” error will be
>>> generated. Either make the grace notes shorter in duration, for example:
>>>
>>> \acciaccatura { c'8[ d' e' f' g'] }
>>> becomes:
>>>
>>> \acciaccatura { c'16[ d' e' f' g'] }
>>> """
>>>
>>> I'm trying to reproduce such an error, just to check if I've understood
>>> it correctly, but I can't.
>>> The combined length of grace notes, in first example, is 5/8. So if I
>>> put a shorter note before the grace expression I should produce an error?
>>>
>>> \version "2.17.10"
>>>
>>> {
>>>    c'16
>>>    \acciaccatura { c'8[ d' e' f' g'] }
>>> }
>>>
>>> It's not working.
>>> I think I'm totally missing the point.
>>
>> Did you include a \midi {} to cause MIDI output to be generated?
>>
>
> Ooops, I'm an idiot! Yes, that's the reason.
>
> Anyway, using a note before the \acciaccatura block in the example would 
> make it more clear?
>
> \version "2.17.10"
>
> \score {
>    {
>      c'8
>      \acciaccatura { c'8[ d' e' f' g'] }
>    }
>    \layout{}
>    \midi{}
> }
>
> The error is triggered also if there isn't any note before the grace 
> notes (for sure they are greater than zero), but the change to 16th note 
> doesn't make sense without specifying the preceding note.
>
> I'm CCing the bug list.

Thanks for the documentation enhancement request, Federico.

I think what you want is to change this section:

http://lilypond.org/doc/v2.17/Documentation/notation/special-rhythmic-concerns

and replace this lilypond source:

\acciaccatura { c'8[ d' e' f' g'] }

with your complete example

\version "2.17.10"

\score {
   {
     c'8
     \acciaccatura { c'8[ d' e' f' g'] }
   }
   \layout{}
   \midi{}
}

I have created a tracker here:

http://code.google.com/p/lilypond/issues/detail?id=3097

> Finally, can you confirm that the string "Going back in MIDI time" is 
> not present in the .pot file? Why?

I understand that your query about the pot file is a non-bug because
such messages are not translated. So, no bug to report there.

Cheers,
Colin.

-- 
Colin Hall