Hear

Boilerplate for Jack and PyAudio

Why?

PyAudio offers a binding for the old good PortAudio, it works everywhere but is quite low-level and if you are using Jack can be painful (ok, it is supported, but I was not able to create a client, nor to find working code by someone else).

Jack-Client is way better, but, obviously, works only with an active Jack server.

I want both.

Usage

To read audio from the microphone:

from hear import hear


def callback(data):
    left  = data[0]
    right = data[1]
    # do stuff

hear(callback)

where data is a NumPy array.

If you have an active Jack server running the callback is processed by a Jack client, otherwise by PyAudio.

hear takes also other arguments:

def hear(callback, channels=2, body=None,
         jack_client="Hear",
         rate=44100, frames_per_buffer=1024):
    ...

body is the action (a function) performed while the client/pa-stream is running, by default:

def body():
    try:
        while True:
            sleep(0.1)
    except KeyboardInterrupt:
        print("Interrupted by user")

jack_client, Jack only, is the client name.

rate and frames_per_buffer are PyAudio only, if you want to reuse the same code switching between the two backends make sure to be using the same values in your Jack configuration.

Installing

pip install hear --allow-unverified pyaudio

Known Issues

• If you change the Jack state you have to reload the whole application. (To check the available backends Hear uses PyAudio, and the C part inizializes everything just one time storing the state in some global variables)