#!/usr/bin/env python
# coding: utf-8

# In[17]:


from numpy import *
get_ipython().run_line_magic('matplotlib', 'notebook')
from matplotlib.pyplot import *
import audio.wave
from IPython.display import Audio


# In[5]:


T = 3.0
df = 44100
dt = 1.0 / 44100
f = 440.0


# In[3]:


t = r_[0.0:T:dt]
t


# In[6]:


x = sin(2*pi*f*t)


# In[15]:


v = r_[0:10]
v < 5


# In[9]:


tf = t[t < 20 / 1000.0] # 20 ms
xf = x[t < 20 / 1000.0]


# In[12]:


fig, axes = subplots()
axes.plot(tf, xf, "+")
axes.grid()


# In[27]:


audio.wave.write(10*x, "A4.wav")
Audio("A4.wav")


# In[28]:


def make_tone(n=4):
    f = 440.0 * 2 ** (n - 4)
    x = sin(2*pi*f*t)
    filename = "A" + str(n) + ".wav"
    audio.wave.write(x, filename)
    return x


# In[32]:


for i in range(0,11):
    x = make_tone(i)
    display(mean(x * x), 27.5 * 2 ** i)
    display(Audio("A" + str(i) + ".wav"))


# In[41]:


x = make_tone(n=20)
Audio("A20.wav")


# In[39]:


27.5 * (2 ** 100)
f, a = subplots()
a.plot(x)


# In[48]:


A4 = make_tone(n=4)
A4q = audio.wave.read("A4.wav")[0]
fig, axes = subplots()
axes.plot(A4[:512], "b+", alpha=0.5, label="original")
axes.plot(A4q[:512], "g+", alpha=0.5, label="write/read")
axes.legend()


# In[49]:


mean(abs(A4 - A4q))


# In[51]:


raw = open("A4.wav").read()
raw[:512]


# In[62]:


from bitstream import *
import warnings; warnings.simplefilter('ignore', DeprecationWarning)
stream = BitStream(raw[:512])
print stream.read(str, 4)
_ = stream.read(str, 4)
print stream.read(str, 4)
print stream.read(str, 4)
_ = stream.read(str, 6)
print stream.read(uint16).newbyteorder() # LE <-> BE
print stream.read(uint32).newbyteorder()