Re: Midi dynamics behaviour changed in latest git HEAD

[Heikki Tauriainen]

Hi,

On Fri, 2016-08-19 at 10:16 -0700, H. S. Teoh wrote:
> I've been using lilypond from git HEAD (mainly because lilypond in my
> distro is too old, still stuck at 2.18, and I need features and fixes
> in 2.19), and recently I noticed that midi dynamics in my piano
> scores aren't being rendered correctly anymore.  Looking into the
> commit log, I saw this:
> 
>     Issue 4947: Link notes to dynamics in Dynamic_performer rather
> than Staff_performer.  Dynamics in different voices are now
> independent.

For some background information, see <https://codereview.appspot.com/30
2930043/> for some discussion (related to Issue #4920) which I believe
led to this change.  (In short, the previous behavior, where all
identically named Voices within a Staff would share their dynamic
changes, was considered to be a bug by some developers, so the behavior
was changed; after the change, every Voice instance will have its
dynamics controlled independently of any other Voice regardless of its
name.)

> It seems that this is the probable cause of the problem, because in
> my piano scores I use a separate Dynamics context to put all
> dynamics, something like this:
> 
>       % This is what midi is actually generated from
>       \score {
>               <<
>                       \new Staff << \rightHandPart \dynamicsPart >>
>                       \new Staff << \leftHandPart \dynamicsPart >>
>               >>
>               \midi {}
>       }

[...]

> Prior to the above git commit, the construct << \rightHandPart
> \dynamicsPart >> would cause dynamics to be merged into
> \rightHandPart.  However, now it appears to be interpreted
> as two separate voices with independent dynamics, so none of the
> dynamics are applied to the actual notes anymore.

Would instantiating the Voice contexts explicitly in the MIDI \score,

<<
    \new Staff \new Voice << \rightHandPart \dynamicsPart >>
    \new
Staff \new Voice << \leftHandPart \dynamicsPart >>              >>

help?  This is what I'd try first to ensure that \rightHandPart and
\dynamicsPart will end up in the same Voice (and not in any separate
implicit Voices which could get instantiated implicitly otherwise).

-- 
Heikki Tauriainen