\version "2.19.55"

#(define (format-moment moment)
    (exact->inexact 
        (/ (ly:moment-main-numerator moment)
        (ly:moment-main-denominator moment))))

#(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 (mkvideo-dump type grob)
    (let* (
        (paper-column (grob-get-paper-column grob))
        (cause        (ly:grob-property grob 'cause))
        (time         (ly:grob-property paper-column 'when 0))
        (start        (+ 0.0 (ly:moment-main time) (* (ly:moment-grace time) (/ 9 40))))
        (duration     (if (ly:prob? cause) (format-moment (ly:duration-length (ly:event-property cause 'duration))) 0.0))
        )
    (if (not (equal? (ly:grob-property grob 'transparent) #t))
        (format #t "\n~8f ~a ~f" start type duration))
    ))

#(define (mkvideo-dump-note grob) (mkvideo-dump "note" grob))
#(define (mkvideo-dump-stem grob) (mkvideo-dump "stem" grob))

\layout {
    \context { \Voice
        \override NoteHead #'after-line-breaking = #mkvideo-dump-note
        \override Stem #'after-line-breaking = #mkvideo-dump-stem
    }
}


\score {{ a1 2 2 4 8 8 16 16 32 32 }}