gistfile1.clj

(ns audiofun.core
  (:import [java.lang Math]
           [javax.sound.sampled AudioFormat
            AudioInputStream AudioSystem Clip DataLine LineEvent LineListener])
)

(defn lowest-byte [^long s]
  (unchecked-byte (bit-and s 255)))

(defn highest-byte [^long s]
  (unchecked-byte (bit-and (bit-shift-right s 8) 255)))

(defn sin[^double f ^double t]
  (let [s (Math/sin (* 2 Math/PI f t))]
    (/ (Math/floor (* s 65535)) 65535)))

(defn to-audio-array [coll]
  "Split 16-bit shorts into two bytes, little endian"
  (byte-array
   (flatten (map (juxt lowest-byte highest-byte) coll))))

(defn sin-sequence
  [^double vol ^double freq ^double t]
  "vol:  Volume in the range [0 1] inclusive"
  "freq: Frequency of sine wave. 440 for A-4"
  "t:    Duration in seconds."
  (for [dur (range 0 (* t 44100))]
     (unchecked-short (* 32767.0 vol (sin freq (float (/ dur 44100)))))))

(defn play-sample [arr]
  (let [samplelen (alength arr)
        audioformat (new AudioFormat
               44100.0                  ;Samplerate (float)
               16                       ; Bits per sample (int)
               1                        ; Number of channels (int)
               true                     ;Signed? (boolean)
               false                    ;Big endian? (boolean)
               )
        strm (new AudioInputStream
                  (new ByteArrayInputStream arr 0 samplelen)
                  audioformat samplelen)
        clip (doto (AudioSystem/getClip)
               (.open strm)                   ; This throws IllegalArgumentException. And it does indeed take an AudioInputStream
               (.loop Clip/LOOP_CONTINUOUSLY)
               (.start))]
    
    #(. clip stop))
  )

(def sin-sample (to-audio-array (sin-sequence 0.5 440.0 1.0)))
(def stop-sample (playsample sin-sample))

; This yields:
; core.clj:51:1:
; error: java.lang.IllegalArgumentException: Invalid format, compiling:(core.clj:51) 

; Class overview:
; http://docs.oracle.com/javase/7/docs/api/javax/sound/sampled/AudioSystem.html
; http://docs.oracle.com/javase/7/docs/api/javax/sound/sampled/AudioInputStream.html
; http://docs.oracle.com/javase/7/docs/api/javax/sound/sampled/AudioFormat.html
; http://docs.oracle.com/javase/7/docs/api/javax/sound/sampled/Clip.html

; http://docs.oracle.com/javase/7/docs/api/javax/sound/sampled/package-summary.html