Panning with PyAudio

# Example modified from
# <http://people.csail.mit.edu/hubert/pyaudio/#docs>
# and
# <http://stackoverflow.com/questions/12076161/playing-a-single-channel-of-audio-using-pyaudio-or-similar>

"""PyAudio Example: Play a WAVE file."""

import pyaudio
import wave
import sys

# Get from the filepool
src = exp.get_file('example.wav')

# Index of the output device or None for default
output_device_index = None

# The chunk size for playing back the stream
chunk_size = 1024

# The channel to play back (0 or 1)
channel = 0

def convert(data, samplesize=2, channel=0):
    for i in range(0, len(data), 2*samplesize):
        for j in range(0, samplesize):
           data[i + j + samplesize * channel] = 0

# Initialize PyAudio and open an output stream
p = pyaudio.PyAudio()
wf = wave.open(src, 'rb')
stream = p.open(format=p.get_format_from_width(wf.getsampwidth()),
    channels=wf.getnchannels(),
    rate=wf.getframerate(),
    output=True,
    output_device_index=output_device_index)

# Read and play stream data until the stream is empty
data = bytearray(wf.readframes(chunk_size))
samplesize = wf.getsampwidth()
while data != '':
    convert(data, samplesize=samplesize, channel=channel)
    stream.write(str(data))
    data = bytearray(wf.readframes(chunk_size))

# Clean up
stream.stop_stream()
stream.close()
p.terminate()