sr       = 44100
kr       = 44100
ksmps    = 1
nchnls   = 1

instr    1 ; Random wavecycle invert

ilevl    = p4                        ; Output level
inv      = p5*2 - 1                  ; % Inverted

ain      soundin  "Sample"

kin      downsamp  ain               ; Convert input to kr
krand    rand  1                     ; Generate random signal
kzero    trigger  kin, 0, 0          ; Detect zero crossings
if       kzero = 0 goto output       ; Do nothing if not zero
if       krand + inv < 0 goto invert ; If random <0 goto invert...
ainvert  = 1                         ; ...if not don't invert...
goto     output                      ; ...then goto output
invert:
ainvert  = -1                        ; Invert wavecycle
output:
out      ain*ainvert*ilevl           ; Level, invert and output

endin