projects
PyTuner
The PyTuner Project
PyTuner was my first serious programming project, which I made for submission to a local technology competition. Through this project I learned alot about Graphical User Interaces (GUIs) and complex data structures within desktop applications. I used fast fourier transforms and linear algebra to transform audio from a raw guitar pluck to a message that tells the user whether or not their string is out of tune.
YIN Algorithm
The YIN algorithm converts waveform-based audio to a signular pitch, which is the entire goal of a guitar tuner.
I used sounddevice to record audio and numpy to perform computations.
The python code for the algorithm is as follows:
def YIN(sig, sr, wl=882, ws=441, f0_min=50,
f0_max=500, ht=0.1):
"""
Implement the YIN algorithm. Notice how
differenceFunction, cummalative_mean_norm_df, and pitch
are all helper functions for this tool.
Parameters:
--------------
sig iterable:
numpy array of audio
sr int:
samplerate
wl=882 int:
length of calculation window for pitch
ws=441 int:
step for calculation window
f0_min=50 int:
minimum frequency threshold
f0_max=500 int:
maximum frequency threshold
ht=0.1 float:
harmonic threshold
"""
t_min = int(sr / f0_max)
t_max = int(sr / f0_min)
timeScale = range(0, len(sig) - wl, ws)
times = [t/float(sr) for t in timeScale]
frames = [sig[t:t + wl] for t in timeScale]
pitches = [0.0] * len(timeScale)
harmonic_rates = [0.0] * len(timeScale)
argmins = [0.0] * len(timeScale)
for i, frame in enumerate(frames):
# Compute YIN
df = differenceFunction(frame, wl, t_max)
CMNDF = cummalative_mean_norm_df(df, wl)
p = pitch(CMNDF, t_min, t_max, ht)
# Get results
if np.argmin(CMNDF) > t_min:
argmins[i] = float(sr / np.argmin(CMNDF))
if p != 0: # A pitch was found
pitches[i] = float(sr / p)
harmonic_rates[i] = CMNDF[p]
else:
harmonic_rates[i] = min(CMNDF)
return pitches, harmonic_rates, argmins, times
Graphical User Interface
For the graphical user interface, I used a library called Tkinter, a simple python library for GUI development. Here is a sample of Tkinter code for a simple dropdown, implemented using object-oriented programming (OOP):
import tkinter as tk
from tkinter import ttk
class LabelDropdown(tk.Frame):
"""
Dropdown - like object which projects a multiline string to GUI
see LabelDropdown.__init__ for more details.
"""
def __init__(self, master, label, buttonlabel, label_font, label_fg, label_bg,
buttonlabel_font, buttonlabel_fg, buttonlabel_bg, indent=' '):
"""__init__.
Parameters
----------
master : tk.Tk
master
label : str
label
buttonlabel : str
label for button
label_font : str
font for button
label_fg : str
forground for button
label_bg : str
background for button
buttonlabel_font : str
font for button
buttonlabel_fg : str
foreground for button
buttonlabel_bg : str
background for button
indent : str
indentation for label
"""
super(LabelDropdown, self).__init__()
self['background'] = '#ffffff'
self.label = label
self.buttonlabel = buttonlabel
self.label_font = label_font
self.label_fg = label_fg
self.label_bg = label_bg
self.buttonlabel_font = buttonlabel_font
self.buttonlabel_fg = buttonlabel_fg
self.buttonlabel_bg = buttonlabel_bg
self.indent = indent
self.button = ttk.Button(self, text=self.buttonlabel+' ▶', style='DD.TButton', command=self.show)
self.button.grid(row=0, column=0)
self.style_init()
def show(self):
"""
Show Label
"""
self.button['command'] = self.hide
self.button['text'] = self.buttonlabel + ' ▼'
self.label_list = self.label.split('\n')
self.label_widgets = []
if len(self.label_widgets) == 0:
for i in range(len(self.label_list)):
self.label_list[i] = self.indent+self.label_list[i] # notice that indent.join(label_list) would leave out the first line.
self.label_widgets.append(ttk.Label(self, text=self.label_list[i], style='DD.TLabel'))
self.label_widgets[i].grid(row=i+1, column=0)
else:
for i in range(len(self.label_widgets)):
self.label_widgets[i].grid(row=i+1,column=0)
def hide(self):
"""
Hide Docstring
"""
self.button['command'] = self.show
self.button['text'] = self.buttonlabel + ' ▶'
for i in self.label_widgets:
i.grid_forget()
def style_init(self):
"""
initialize styles
"""
self.style = ttk.Style(self)
self.style.configure('DD.TLabel',
font=self.buttonlabel_font,
foreground=self.buttonlabel_fg,
background=self.buttonlabel_bg,
relief='flat', pady=10)
self.style.configure('DD.TButton',
font=self.buttonlabel_font,
foreground=self.buttonlabel_fg,
background=self.buttonlabel_bg,
relief='flat')
self.style.map('DD.TButton',
foreground=[('active', '#000000')],
background=[('active', '#ffffff')])
self.style.layout('DD.TButton',
[('Button.button',
{'sticky': 'nswe', 'children':
#[('Button.padding', {'sticky': 'nswe', 'children':
[('Button.label', {'sticky': 'nswe'})]
# })]
})]
)