karaoke.py

from doctest import OutputChecker
import pyaudio 
import numpy as np
import wave, os
from datetime import detetime
from audioop import mul, add, bias

#brew install portaudio
#pip install pyaudio

INPUT_INDEX = 5
OUTPUT_INDEX = 3
OUTPUT_FILENAME = 'output/%s.wav' % (datetime.now().strftime('%Y-%m-%d_%H-%M-%S'))
os.makedirs('output', exist_ok = True)

CHUNK = 512
RATE = 48000
SAMPLE_WIDTH = 2
DELAY_INTERVAL = 15
DELAY_VOLUME_DECAY = 0.6
DELAY_N = 10

#delay sound
original_frames = []
index = 0

def add_delay(input):
    global original_frames, index

    original_frames.append(input)
    output = input

    if len(original_frames) > DELAY_INTERVAL:
        for n_repeat in range(DELAY_N):
            delay = original_frames[max(index - n_repeat * DELAY_INTERVAL, 0)]
            delay = mul(delay, SAMPLE_WIDTH, DELAY_VOLUME_DECAY ** (n_repeat + 1))
            output = add(output, delay, SAMPLE_WIDTH)

        index += 1

    return output

def start_stream():
    #open devices
    stream = pa.open(
        format = pyaudio.paInt16,
        channels=1,
        rate = RATE,
        frames_per_buffer = CHUNK,
        input = True,
        output = True,
        input_device_index = INPUT_INDEX,
        output_device_index = OUTPUT_INDEX
    )

    frames = []

    while stream.is_active():
        try:
            input = stream.read(CHUNK, exception_on_overflow=False)
            input = add_delay(input)

            stream.write(input)
            frames.append(input)
        except KeyboardInterrupt:
            break
        except Exception as e:
            print('[!] Unknown error!', e)
            exit ()

    total_frames = b''.join(frames)

    with wave.open(Output_FILENAME, 'wb') as f:
        f.setnchannels(1)
        f.setsampwidth(pa.get_sample_size(pyaudio.paInt16))
        f.setframerate(RATE)
        f.writeframes(total_frames)

        
    stream.stop_stream()
    stream.close()
    pa.terminate()

#main
pa = pyaudio.PyAudio()

for i in range(pa.get_device_count()):
    print(pa.get_device_info_by_index(i))

start_stream()