DrawWaveform — wiki

# python built in array type is useful for storing sound data.
import array
# a square wave tone, with sample values between -32766 and 32766.
samples = array.array('h', [32766, 32766, 32766, 32766, 32766, 32766,
32766, 32766, 32766, 32766, 32766, 32766, 32766, 32766, 32766,
32766, 32766, 32766, 32766, 32766, 32766, 32766, 32766, 32766,
32766, 32766, 32766, 32766, -32766, -32766, -32766, -32766,
-32766, -32766, -32766, -32766, -32766, -32766, -32766, -32766,
-32766, -32766, -32766, -32766, -32766, -32766, -32766, -32766,
-32766, -32766, -32766, -32766, -32766, -32766, -32766])


def scale_samples_to_surf(width, height, samples):
    """ Returns a generator containing (x, y) to draw a waveform.

    :param width: width of surface to scale points to.
    :param height: height of surface to scale points to.
    :param samples: an array of signed 1 byte or signed 2 byte.
    """
    assert samples.typecode in ['h', 'b']
    # precalculate a bunch of variables, so not done in the loop.
    len_samples = len(samples)
    width_per_sample = width / len_samples
    height_1 = height - 1

    if samples.typecode == 'h':
        # for array typecode 'h', -32768 to 32768
        factor = 1.0 / 65532
        normalize_modifier = int(65532 / 2)
    elif samples.typecode == 'b':
        # for array typecode 'b', -127 to 127
        factor = 1.0 / 256
        normalize_modifier = int(256 / 2)

    return ((
        int((sample_number + 1) * width_per_sample),
        int(
            (1.0 -
                (factor *
                    (samples[sample_number] + normalize_modifier)))
            * (height_1)
        ))
    for sample_number in range(len_samples))

def draw_wave(surf,
              samples,
              wave_color = (0, 0, 0),
              background_color = pg.Color('white')):
    """Draw array of sound samples as waveform into the 'surf'.

    :param surf: Surface we want to draw the wave form onto.
    :param samples: an array of signed 1 byte or signed 2 byte.
    :param wave_color: color to draw the wave form.
    :param background_color: to fill the 'surf' with.
    """
    assert samples.typecode in ['h', 'b']
    if background_color is not None:
        surf.fill(background_color)
    width, height = surf.get_size()
    points = tuple(scale_samples_to_surf(width, height, samples))
    pg.draw.lines(surf, wave_color, False, points)

# Here we should how to draw it onto a screen.
waveform = pg.Surface((320, 200)).convert_alpha()
draw_wave(waveform, samples)
screen.fill((255, 255, 255))
screen.blit(waveform, (160, 100))