#!/usr/bin/env python3

"""Pass input directly to output.

https://github.com/PortAudio/portaudio/blob/master/test/patest_wire.c

"""

import argparse

import sounddevice as sd

import numpy # Make sure NumPy is loaded before it is used in the callback

assert numpy # avoid "imported but unused" message (W0611)

def int_or_str(text):

"""Helper function for argument parsing."""

try:

return int(text)

except ValueError:

return text

parser = argparse.ArgumentParser(add_help=False)

parser.add_argument(

'-l', '--list-devices', action='store_true',

help='show list of audio devices and exit')

args, remaining = parser.parse_known_args()

if args.list_devices:

print(sd.query_devices())

parser.exit(0)

parser = argparse.ArgumentParser(

description=__doc__,

formatter_class=argparse.RawDescriptionHelpFormatter,

parents=[parser])

parser.add_argument(

'-i', '--input-device', type=int_or_str,

help='input device (numeric ID or substring)')

parser.add_argument(

'-o', '--output-device', type=int_or_str,

help='output device (numeric ID or substring)')

parser.add_argument(

'-c', '--channels', type=int, default=2,

help='number of channels')

parser.add_argument('--dtype', help='audio data type')

parser.add_argument('--samplerate', type=float, help='sampling rate')

parser.add_argument('--blocksize', type=int, help='block size')

parser.add_argument('--latency', type=float, help='latency in seconds')

args = parser.parse_args(remaining)

def callback(indata, outdata, frames, time, status):

if status:

print(status)

outdata[:] = indata

try:

with sd.Stream(device=(args.input_device, args.output_device),

samplerate=args.samplerate, blocksize=args.blocksize,

dtype=args.dtype, latency=args.latency,

channels=args.channels, callback=callback):

print('#' * 80)

print('press Return to quit')

print('#' * 80)

input()

except KeyboardInterrupt:

parser.exit(1, '\nInterrupted by user')

except Exception as e:

parser.exit(1, type(e).__name__ + ': ' + str(e))