CODEWITHSUNDEEP
pythonaudiopyaudio
ElanaLS
ElanaLS

Reputation: 21

Generate audio on just one channel pyaudio

I have the following code that generates a sin wave of a specific frequency and plays it using pyaudio. I would like to change it such that the audio is only generated on the left, or only on the right speaker channel. How would I do this?

import math
import struct
import pyaudio

def play_tone(frequency, amplitude, duration, fs, stream):
    N = int(fs / frequency)
    T = int(frequency * duration)  # repeat for T cycles
    dt = 1.0 / fs
    # 1 cycle
    tone = (amplitude * math.sin(2 * math.pi * frequency * n * dt) for n in xrange(N))
    print type(tone)
    # todo: get the format from the stream; this assumes Float32
    data = ''.join(struct.pack('f', samp) for samp in tone)
    for n in xrange(T):
        stream.write(data)

fs = 48000
p = pyaudio.PyAudio()
stream = p.open(
   format=pyaudio.paFloat32,
   channels=1,
   rate=fs,
   output=True)

play_tone(200, 0.5, 0.75, fs, stream)

stream.close()
p.terminate()

Upvotes: 2

Views: 1895

Answers (1)

J. Doe
J. Doe

Reputation: 429

At first you should change channels=1 to channels=2. Then you should modify your play_tone function to make it generate stereo signal instead mono. Usually you should interleave samples for left and right channels in following pattern: LRLRLRLRLRLR...

Since you need to play sound via single channel then just put zeros for either left or right component of sample.

Upvotes: 1

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