Simple ear training script

ear.py

import math
import time
import ossaudiodev
import random

#   Simple ear training script - by Andre Lima
#
#   This program is based on code from:
#
#   tone.py - Single / Dual Tone Generator
#   Copyright (C) 2006-2009 Martin S. Ewing, AA6E
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

LA = 440.
SEMI_TONE = 2 ** (1/12.0)
TONE = 2 ** (1/6.0)

AMP = 50.
DSP = '/dev/dsp'

def f_sin(i, a, f1, bl):
    aa = a * 32.767
    o = 2.0 * math.pi / float(bl)
    v = aa * math.sin(f1*i*o) 
    v *= 2
    return v

def do_sound(afout, f1, times):
    buflen = int(times * afout.bufsize() / 8)
    fmin = float(speed) / float(buflen)
    ff1 = round(f1 / fmin)
    data = ''
    aa = 32767.0 * (AMP / 100.0)
    oo = 2.0 * math.pi / float(buflen)
    for iy in range(buflen):
        vv = f_sin(iy, AMP, ff1, buflen)
        val = int(vv)
        c1 = chr(val & 0xff)
        c2 = chr((val & 0xff00) >> 8)
        data = data + c1 + c2
    afout.write(data)
    while afout.obufcount() > 0:
        time.sleep(0.01)

def get_guess(text):
    raw_guess = raw_input(text)
    try:
        return int(raw_guess)
    except ValueError:
        return raw_guess

if __name__ == '__main__':
    speeds = {1: 8000, 2: 11025, 3: 22050, 4: 44100, 5: 96000}
    speed = speeds[4]

    base = LA * (SEMI_TONE ** 3)
    notes = ["do", "do#", "re", "re#", "mi", "fa", "fa#",
             "sol", "sol#", "la", "la#", "si"]

    pitches = []
    pitch = {}
    for i, note in enumerate(notes):
        pitch[note] = base * (SEMI_TONE ** i)
        pitches.append(pitch[note])

    afout = ossaudiodev.open(DSP, 'w')
    afout.setparameters(ossaudiodev.AFMT_S16_LE, 0, speed)

    do_major_scale = [x for x in notes if "#" not in x]

    options = [0, 2, 4, 6]
    print options

    count, good = 0, 0
    while True:
        d = random.choice(options)
        do_sound(afout, pitches[0], 1)
        do_sound(afout, pitches[d], 1)
        guess = get_guess("Guess: ")
        while guess not in options:
            if guess == "?":
                print "Repeating sound..."
                do_sound(afout, pitches[0], 1)
                do_sound(afout, pitches[d], 1)
            elif guess == "!":
                print "Exiting..."
                exit(0)
            else:
                print "(Invalid option: %s)" % str(guess)
            guess = get_guess("Guess: ")
        print "Actual:", d,
        count += 1
        if d == guess:
            print " (Good!)"
            good += 1
        else:
            print " (Sorry...)"
        print "Score: %d/%d (%d%%)." % (good, count, int(float(good)*100/count))
        print

    afout.close()