Convert tab indentation into music

from struct import pack
from math import sin, pi
import time

x=0
lines=[0,0,0,0,0,0]
f=[523.25,587.33,659.26,783.99,880]

def freq(i):
    return f[i%len(f)] * 2**(i/len(f))

def saw(phase):
    phase = phase%2
    return phase-1

def tri(phase):
    phase = phase%2
    if(phase>1):
        phase = 2-phase
    return -1 + 2*phase

fout = open('output.au', 'wb')
rate = 44100
leng = 750
phase = 0.0
phase2 = 0.0
dur = rate/10
# header needs size, encoding=2(8 bit pcm), sampling_rate=8000, channel=1
fout.write('.snd' + pack('>5L', 24, dur*leng, 2, rate, 1))
for i in range(leng):
    lines[x] = raw_input().count("  ");
    x2 = (x+1)%len(lines)
    for seg in range(dur):
        #step = 2**(lines[x]/6.0) * 880 / rate
        step = freq(lines[x]) / rate
        phase = phase + step
        #sin_seg = tri(phase)
        #step = 2**(lines[x]/6.0) * 880 / rate
        step = freq(lines[x2]) / rate
        phase2 = phase2 + step
        sin_seg = tri(phase) + tri(phase2)
        fout.write(pack('b', 63 * sin_seg))
    x=x2
fout.close()