io:read-midi-file

(io:read-midi-file file-path)


Description:

Reads a midi file and returns a list structure represeting that midi-file.  the stucture is one list per track.  each track list is seperated into lists of start-times pitches volumes and durations(in beats).  trying reading a simple midi-file and printing the result to the log.


Arguments:


Returns: boolean


Examples:

;; setup audio unit graph

(define synth (au:make-node "aumu" "dls " "appl"))

(au:connect-node synth 0 *au:output-node* 0)

(au:update-graph)

;; send program change to dls audio units

(au:midi-out (now) synth *midi-pc* 68 0) ; oboe

(au:midi-out (now) synth *midi-pc* 71 1) ; clarinet

(au:midi-out (now) synth *midi-pc* 60 2) ; horn

(au:midi-out (now) synth *midi-pc* 70 3) ; bassoon

;; read midi file

(define chorale (io:read-midi-file "/tmp/bach.mid"))

;; marker

; Events can have a marker number attached to them

; to allow us to mute/ignore them even after they have been

; scheduled. (See below).

(define marker 100)

;; Play a MIDI track

; The list-ref function is an Impromptu function that 

; allows the acceesing of elements within a list by index.

; The consing of the play-note time and marker attaches

; the marker number of the note events (start and stop).

(define (play-seq time inst midi-track chan)

   (map (lambda (t p v r)

           (play-note (cons (+ time (* t *second*)) marker) inst p v (* r *second*) chan))

        (list-ref midi-track 0)

        (list-ref midi-track 1)

        (list-ref midi-track 2)

        (list-ref midi-track 3)))

;; Play the first four tracks

(define (chorale-player time score)

   (play-seq time synth (list-ref score 3) 0)

   (play-seq time synth (list-ref score 2) 1)

   (play-seq time synth (list-ref score 1) 2)

   (play-seq time synth (list-ref score 0) 3))

;; Start - give play-seq 2 seconds to load the file.

(chorale-player (+ (now) (* *second* 2)) chorale)



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