Hello list,
ly2video generates a horizontal scrolling video from one large png. I
am trying to modify ly2video to produce a different kind of video that
looks like this:
https://www.youtube.com/watch?v=Jb5qj6rQv14
It involves multiple 'snippets' of sheet music that are all the same
width. To get there I used a custom paper size:
#(set! paper-alist (cons '("vid-line" . (cons (* 90 mm) (* 26 mm)))
paper-alist))
\paper {
#(set-paper-size "vid-line")
}
When I run lilypond to output pngs, I get nicely formatted music
snippets in multiple pngs. I can then scale them to the video width
using python to create pngs and eventually a video.
On a side note it would be nicer to specify the resolution of the image
I need (so I don't have to scale), but these options:
#(ly:set-option 'png-width 1920)
#(ly:set-option 'png-height 300)
Don't seem to work.
The main issues I have relate to the page numbers.
The first issue is that lilypond produces files like: video-page1.png
and video-page10.png. This requires a natural sorting algorithm that's
not built into python. It can be done, but if lilypond could take a
format specifier that was 3 digits long to produce video-page001.png,
it would make things easier.
The second issue is that the space-time-dumper in ly2video produces
what I need, but there are no page transitions indicated. I can
probably work out the transitions from when the x coordinate wraps, but
it would be nice to have the page change show up in the spacetime info
output. Ideally with the page number.
I put together a rather complicated mwe for anyone able to help. It's
two files. I kept the spacetime dumper code in a separate file.
The output will be noisy. On linux you can run it like this:
lilypond --png mwe.ly | grep ly2video > spacetime.txt
to dump the spacetime info to a file.
Thanks,
Stef
\include "dump-spacetime-info.ly"
#(define drumtable '(
(bassdrum () #f -3)
(snare () #f 1)
(hihat cross #f 5)
))
drumMusic = \drummode {
<<
{ hh8[ hh] <hh sn>[ hh] hh[ hh] <hh sn>[ hh] }
\\
{ bd4 s4 bd4 s4 }
>>
}
theMusic = \new DrumStaff {
\set DrumStaff.drumStyleTable = #(alist->hash-table drumtable)
% TODO: figure out how to relocate tempo mark so that it doesn't
% impact the vertical height of staves.
% \tempo 4 = 100
\repeat unfold 40 \drumMusic
}
\score {
\unfoldRepeats { \theMusic }
\layout {
\context {
\Score
\omit BarNumber
% make only the first clef visible
\override Clef #'break-visibility = #'#(#f #f #f)
% make only the first time signature visible
\override KeySignature #'break-visibility = #'#(#f #f #f)
}
}
\midi {
}
}
#(set! paper-alist (cons '("vid-line" . (cons (* 90 mm) (* 26 mm))) paper-alist))
\paper {
#(set-paper-size "vid-line")
print-page-number = ##f
% remove indentation
indent = 0.0
short-indent = 0.0
% This hack tries to keep the staves in the same vertical place
% otherwise the vertical position flucuates due to the height of the
% tallest beam.
top-system-spacing.basic-distance = #7
}
% is there a better way to unset the entire header block?
\header {
print-all-headers = ##f
title = ##f
composer = ##f
copyright = ##f
tagline = ##f
}
% increase png resolution
#(ly:set-option 'resolution 300)
% setting this option doesn't work like the command line option.
%#(ly:set-option 'backend 'png)
% pngalpha doesn't work.
%#(ly:set-option 'pixmap-format "pngalpha")
% does not work
%#(ly:set-option 'png-width 1920)
%#(ly:set-option 'png-height 300)
% lilypond --png ../mwe.ly | grep ly2video > spacetime.txt
\version "2.20.0"
% Huge thanks to Jan Nieuwenhuizen for helping me with this!
#(define (grob-get-ancestor-with-interface grob interface axis)
(let ((parent (ly:grob-parent grob axis)))
(if (null? parent)
#f
(if (grob::has-interface parent interface)
parent
(grob-get-ancestor-with-interface parent interface axis)))))
#(define (grob-get-paper-column grob)
(grob-get-ancestor-with-interface grob 'paper-column-interface X))
#(define (dump-spacetime-info grob)
(let* ((extent (ly:grob-extent grob grob X))
(system (ly:grob-system grob))
(x-extent (ly:grob-extent grob system X))
(left (car x-extent))
(right (cdr x-extent))
(paper-column (grob-get-paper-column grob))
(time (ly:grob-property paper-column 'when 0))
(cause (ly:grob-property grob 'cause))
(origin (ly:event-property cause 'origin))
(location (ly:input-file-line-char-column origin))
(file (list-ref location 0))
(line (list-ref location 1))
(char (list-ref location 2))
(column (list-ref location 3))
(drum-type (ly:event-property cause 'drum-type))
(pitch (if (null? drum-type)
(ly:event-property cause 'pitch)
(ly:assoc-get drum-type midiDrumPitches)))
(midi-pitch (if (ly:pitch? pitch) (+ 0.0 (ly:pitch-tones pitch)) "no pitch")))
(if #f (format #t "\nly2video: # pitch ~a drum-type ~a ~a" pitch drum-type (null? drum-type)))
(if (not (equal? (ly:grob-property grob 'transparent) #t))
(format #t "\nly2video: (~23,16f, ~23,16f) pitch ~d:~a:~a @ ~23,16f from ~a:~3d:~d"
left right
(if (ly:pitch? pitch) (ly:pitch-octave pitch) 0)
(if (ly:pitch? pitch) (ly:pitch-notename pitch) "?")
(if (ly:pitch? pitch) (ly:pitch-alteration pitch) "?")
(+ 0.0 (ly:moment-main time) (* (ly:moment-grace time) (/ 9 40)))
file line char))))
#(define (dump-spacetime-info-barline grob)
(let* ((extent (ly:grob-extent grob grob X))
(system (ly:grob-system grob))
(x-extent (ly:grob-extent grob system X))
(left (car x-extent))
(right (cdr x-extent))
(paper-column (grob-get-paper-column grob))
(time (ly:grob-property paper-column 'when 0))
(cause (ly:grob-property grob 'cause)))
(if (not (equal? (ly:grob-property grob 'transparent) #t))
(format #t "\nly2videoBar: (~23,16f, ~23,16f) @ ~23,16f"
left right
(+ 0.0 (ly:moment-main time) (* (ly:moment-grace time) (/ 9 40)))
))))
\layout {
\context {
\DrumVoice
\override NoteHead.after-line-breaking = #dump-spacetime-info
}
\context {
\DrumStaff
\override BarLine.after-line-breaking = #dump-spacetime-info-barline
}
\context {
\Voice
\override NoteHead.after-line-breaking = #dump-spacetime-info
}
\context {
\Staff
\override BarLine.after-line-breaking = #dump-spacetime-info-barline
}
\context {
\ChordNames
\override ChordName.after-line-breaking = #dump-spacetime-info
}
}
