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

# # Introduction to pysptk
# 
# - windowing
# - mel-generalized cepstrum analysis
# - visualize spectral envelope estimates
# 
# ## Extra requires
# 
# - matplotlib
# - scipy

# In[2]:


get_ipython().run_line_magic('pylab', 'inline')


# In[3]:


import matplotlib
matplotlib.style .use("ggplot")

rcParams['figure.figsize'] = 16, 7


# In[4]:


import numpy as np
from scipy.io import wavfile
import pysptk


# In[5]:


fs, x = wavfile.read("test16k.wav")
assert fs == 16000


# In[6]:


plot(x)
xlim(0, len(x))
title("raw waveform of test16k.wav")


# ## Windowing

# In[7]:


# Pick a short segment
pos = 3000
frame_length = 1024

xw = x[pos:pos+frame_length] * pysptk.blackman(frame_length)

plot(xw, linewidth=3.0)
xlim(0, frame_length)
title("a windowed time frame")


# In[8]:


# plotting utility
def pplot(sp, envelope, title="no title"):
    plot(sp, "b-", linewidth=2.0, label="Original log spectrum 20log|X(w)|")
    plot(20.0/np.log(10)*envelope, "r-", linewidth=3.0, label=title)
    xlim(0, len(sp))
    xlabel("frequency bin")
    ylabel("log amplitude")
    legend(prop={'size': 20})


# In[9]:


# Compute spectrum 20log|X(w)| for a windowed signal
sp = 20*np.log10(np.abs(np.fft.rfft(xw)))


# In[10]:


mgc = pysptk.mgcep(xw, 20, 0.0, 0.0)
pplot(sp, pysptk.mgc2sp(mgc, 0.0, 0.0, frame_length).real, title="Lineaer frequency cepstrum based envelope")


# In[11]:


mgc = pysptk.mcep(xw, 20, 0.41)
pplot(sp, pysptk.mgc2sp(mgc, 0.41, 0.0, frame_length).real, title="Mel-cepstrum based envelope")


# In[12]:


mgc = pysptk.mgcep(xw, 20, 0.0, -1.0)
pplot(sp, pysptk.mgc2sp(mgc, 0.0, -1.0, frame_length).real, title="LPC cepstrum based envelope")


# In[13]:


mgc = pysptk.mgcep(xw, 20, 0.41, -1.0)
pplot(sp, pysptk.mgc2sp(mgc, 0.41, -1.0, frame_length).real, title="Warped LPC cepstrum based envelope")


# In[14]:


mgc = pysptk.gcep(xw, 20, -0.35)
pplot(sp, pysptk.mgc2sp(mgc, 0.0, -0.35, frame_length).real, title="Generalized cepstrum based envelope")


# In[15]:


mgc = pysptk.mgcep(xw, 20, 0.41, -0.35)
pplot(sp, pysptk.mgc2sp(mgc, 0.41, -0.35, frame_length).real, title="Mel-generalized cepstrum based envelope")