Re: Experience with several import filters

[David Wright]

On Wed 04 Jan 2017 at 01:23:50 (+0100), Noeck wrote:
> > midi2ly
> 
> I used it for freely licensed scores on cpdl or imslp which are not
> created in LilyPond and too ugly to use in a choir. Sometimes midi files
> are published together with the pdf or the proprietary format.

An exchange on this list six months ago made me take another look at
midi2ly, and I did try it on a couple of scores.

> The
> result was never usable directly (all voices in one staff without
> collision-avoidance/voice-association,

I've certainly found multiple voices in each staff, but it seemed
to correlate with the associated PDF file: ie chords there, then
chords in the MIDI.

As with rosegarden, I just duplicate the part, then use emacs macros
to prune each single voice from the chords. For the soprano:
  <a f >8 <g e >8 <a e >8
 Rubout the <
 Search for space
 Mark
 Search for >
 Cut
 Search for next <
producing
  a 8 g 8 a 8

> no or bad lyrics,

Again, this seems to depend on whether the originator bothered to add
them. In any case, I personally don't use them. I prefer to know the
source, and to do my own hyphenation (in singer's style rather than
publisher's). Were I to need a score with repeats in both folded and
unfolded forms, it might be worth taking advantage of midi2ly's
duration-tagged syllables, but I rarely do. Long may they remain,
however. (I guess I need to register with midi.org to see what I'm
missing in RP-017.)

> wrong key,

ly "reformat; translate english; abs2rel; transpose c c" -o output.ly 
ex-midi2ly.ly

looks after that.

> scaled durations, i.e. a4*234/128 s4*22/128 instead of a2 - the latter
> problem might by fixed by finding an appropriate quanization).

Yes, I use:

alias midi2ly16="~/bin/midi2ly --start-quant=16 --duration-quant=16 
--explicit-durations"
alias midi2ly8="~/bin/midi2ly --start-quant=8 --duration-quant=8 
--explicit-durations"

to save some typing, which just leaves tuplets to add when necessary.
I suppose I ought to try out --key sometime, but I rely on ly.

> The problems ranged from ly files that are easily fixed to some cases
> where it was much faster to rewrite everything from scratch. I guess it
> depends on the application writing the midi file. I never systematically
> cared about that.

Yes, the worst for me is where the barring is (IMHO) misguided.
I don't like using Completion_heads_engraver in my own scores
but midi2ly makes full use of it (and rests). The introduction
of unattached durations in 2.19 helps, so one can interactively
global-edit, say, f2. → f2~ 4 with care, but doing a lot of that
makes one question whether it's worth it.

> Summary: Most of the time, midi2ly gave me a file from which I could
> extract single voices, fix some errors and put them into my own ly
> skeleton and it was worth having the tool.

Agreed.

Cheers,
David.