Real-time audio signal processing using python

Question

I have been trying to do real-time audio signal processing using 'pyAudio' module in python. What I did was a simple case of reading audio data from microphone and play it via headphones. I tried with the following code(both Python and Cython versions). Thought it works but unfortunately it is stalls and not smooth enough. How can I improve the code so that it will run smoothly. My PC is i7, 8GB RAM.

Python Version

import pyaudio
import numpy as np

RATE    = 16000
CHUNK   = 256
    
p               =   pyaudio.PyAudio()

player = p.open(format=pyaudio.paInt16, channels=1, rate=RATE, output=True, 
frames_per_buffer=CHUNK)
stream = p.open(format=pyaudio.paInt16, channels=1, rate=RATE, input=True, frames_per_buffer=CHUNK)

for i in range(int(20*RATE/CHUNK)): #do this for 10 seconds
    player.write(np.fromstring(stream.read(CHUNK),dtype=np.int16))
stream.stop_stream()
stream.close()
p.terminate()

Cython Version

import pyaudio
import numpy as np

cdef int RATE   = 16000
cdef int CHUNK  = 1024
cdef int i      
p               =   pyaudio.PyAudio()

player = p.open(format=pyaudio.paInt16, channels=1, rate=RATE, output=True, frames_per_buffer=CHUNK)
stream = p.open(format=pyaudio.paInt16, channels=1, rate=RATE, input=True, frames_per_buffer=CHUNK)

for i in range(500): #do this for 10 seconds
    player.write(np.fromstring(stream.read(CHUNK),dtype=np.int16))
stream.stop_stream()
stream.close()
p.terminate()

Answer 1

I believe you are missing CHUNK as second argument to player.write call.

player.write(np.fromstring(stream.read(CHUNK),dtype=np.int16),CHUNK)

Also, not sure if its formatting error. But player.write needs to be tabbed into for loop

And per pyaudio site you need to have RATE / CHUNK * RECORD_SECONDS and not RECORD *RATE/CHUNK as python executes * multiplication before / division.

for i in range(int(20*RATE/CHUNK)): #do this for 10 seconds
    player.write(np.fromstring(stream.read(CHUNK),dtype=np.int16),CHUNK)

stream.stop_stream()
stream.close()
p.terminate()

Finally, you may want to increase rate to 44100 , CHUNK to 1024 and CHANNEL to 2 for better fidelity.