Re: Experience with several import filters

[Urs Liska]

Hi Karl,

thanks for the detailed feedback. Could I summarize this as "it does
work but not really satisfactorily. Depending on the kind of input there
will be substantial cleanup to be done"?

Do you actually use it in your work, or did you just make something up
upon my question?

Best
Urs


Am 03.01.2017 um 12:48 schrieb address@hidden:
> Urs:
>> midi2ly
> Here we are talking of program (programs mainly used to make scores) 
> generated midi files.
>
> It kindof works, but has problems with
>
> ////// lyrics
> /// character encoding
> The midi file format standard says (about text events, [1] page 10):
>  However, other characters codes
>  using the high-order bit may be used for interchange of files between
>  different programs on the same computer which supports an extended
>  character set. Programs on a computer       which  does not support
>  non-ASCII characters should ignore those characters.
> Soo, there is a need to identify which encoding is used, and midi2ly 
> gives you errors like "warning: non-UTF-8 input"
> /// word combining
> E.g. given lyrics like:
>  'Sta' 'bat ' 'Ma' 'ter ' 'do' 'lo' 'ro' 'sa ' 
> RP-017 (recommended practice 17, see [2]) implies that it in lilypond
> code should become
>  Sta -- bat Ma -- ter do -- lo -- ro -- sa
> Instead midi2ly gives me 
>   "Sta"2 "bat " 
>   | % 2
>   "Ma" "ter "4 "do"2 "lo"4 "ro"2 
>   | % 4
>   "sa "4*15
> /// assoiation with a voice
> The first few events in track 1 of [4] is
>         ['track_name', 0, 'S1'],
> ...
>         ['lyric', 0, 'Sta'],
>         ['note_on', 0, 0, 69, 80],
>         ['note_off', 959, 0, 69, 64],
>         ['lyric', 1, 'bat '],
>         ['note_on', 0, 0, 71, 110],
>         ['note_off', 959, 0, 71, 64],
> and there is no simultaneous music in the same track and it is clear
> that this lyrics belongs to this voice, but midi2ly doesn't identify
> that, it treats the lyrics as a totatly independent thing to the music
> where I would have liked a result like:
>
> lS_I = \context Lyrics = LS_I \lyricmode { ... }
> mS_I = \context Voice  = VS_I \relative f { ... }
>
> \score {
>   \new ChoirStaff <<
>     \new Staff mS_I
>     \lyricsto VS_I \LS_I
>   >>
> }
>
> or similar.
>
> ////// notes
> /// midi2ly uses Completion_heads_engraver
> instead of splitting notes at the bar lines and using ties
>
> /// note durations
> I get lilypond code like
>
> trackBchannelB = \relative c {
>   a''4*959/480 r4*1/480 b4*959/480 r4*1/480 
>   | % 2
>   c4*959/480 r4*1/480 c4*479/480 r4*1/480 c4*959/480 r4*1/480 c4*479/480 
>   r4*1/480 ais4*959/480 r4*1/480 
>
> where I would have expected
>
> MaA = \relative f {
>   \time 2/2
>   \key c \major
>   a'2 b |
>   c2 c4 c2 c4 ais2 |
>
> As you can see the notes are ended early and midi2ly inserts a very 
> short little rest. In this piece [3,4], the three shortest note
> durations are
>
> Duration 1/4     Count note_len
>    108   0.2250      1 *(108)*
>    119   0.2479      8 *(119)*
>    120   0.2500      5 16
>
> in that view it is not reasonable to treat a silence of duration 1
> as a rest. It seems that $quanta = int($duration[0]*0.6) works well
> for that kind of things and durations such as the three above is
> better treated as phrasing than followed by a rest.
>
> (Also, you might treat a note duration of 0 as an \appogiatura
> (not present in my example [3,4]).)
>
> /// missing \time
> see the above example and "track 0" below
>
> /// missing \key
> even though \key c \major is default, its nice to write it out
>
> ////// score
> I get
>
> trackI = <<
>
>   \clef bass
>   
>   \context Lyrics = voiceA \trackIchannelA
>   \context Voice = voiceB \trackIchannelB
>
> \score {
>   <<
>     \context Lyrics=trackB \trackB
>     \context Lyrics=trackC \trackC
>     \context Lyrics=trackD \trackD
>     \context Lyrics=trackE \trackE
>     \context Lyrics=trackF \trackF
>     \context Lyrics=trackG \trackG
>     \context Lyrics=trackH \trackH
>     \context Lyrics=trackI \trackI
>   >>
>   \layout {}
>   \midi {}
> }
>
> which gives me everything on a single staff instead of 8.
>
> ////// track 0
>
>     # Track #0 ...
>     MIDI::Track->new({
>       'type' => 'MTrk',
>       'events' => [  # 8 events.
>         ['track_name', 0, 'Stabat Mater Dolorosa'],
>         ['time_signature', 0, 2, 1, 48, 8],
>         ['set_tempo', 0, 454540],
>         ['time_signature', 140160, 3, 2, 24, 8],
>         ['set_tempo', 0, 416660],
>         ['time_signature', 28800, 2, 1, 48, 8],
>         ['set_tempo', 0, 454540],
>         ['end_track', 186240],
>       ]
>     }),
>
> is converted to 
>
> trackAchannelA = {
>   
>   \set Staff.instrumentName = "Stabat Mater Dolorosa"
>   
>   \time 2/2 
>   
>   \tempo 4 = 132 
>   \skip 1*73 
>   \time 3/4 
>   
>   \tempo 4 = 144 
>   \skip 1*15 
>   \time 2/2 
>   
>   \tempo 4 = 132 
>   
> }
>
> where the track_name of track 0 is better converted to
>
> \header {
>   title = "Stabat Mater Dolorosa"
> }
>
> and I would like \time to be included in the music.
>
> Regards,
> /Karl Hammar
>
> [1] http://www.music.mcgill.ca/~ich/classes/mumt306/midiformat.pdf
> [2] https://www.midi.org/specifications/item/standard-midi-files-smf
> [3] http://www.johnkilpatrick.co.uk/music/misc/stabat-palestrina-e.pdf
> [4] http://www.johnkilpatrick.co.uk/music/misc/stabat-palestrina-e.mid
>
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