Sharing a table with a numpy array using the buffer protocol — Pyo 1.0.4 documentation

Pyo 1.0.4 documentation

# Sharing a table with a numpy array using the buffer protocol

04-buffer-interface.py

This example shows two things:

1. How to share memory from a PyoTableObject to a numpy array with the getBuffer() method of the PyoTableObject. Numpy functions can then be used to modify the table’s content without copying every samples.

2. How to register a callback function, with the setCallback() method of the Server object, that the server will call at the beginning of every processing loop (each buffersize samples).

Note

The numpy module must be installed for this example to work.

    from pyo import *
    import numpy as np

    s = Server().boot()

    # Get the length of an audio block.
    bs = s.getBufferSize()

    # Create a table of length `buffer size` and read it in loop.
    t = DataTable(size=bs)
    osc = TableRead(t, freq=t.getRate(), loop=True, mul=0.1).out()

    # Share the table's memory with a numpy array.
    arr = np.asarray(t.getBuffer())

    def process():
        "Fill the array (so the table) with white noise."
        arr[:] = np.random.normal(0.0, 0.5, size=bs)

    # Register the `process` function to be called at the beginning
    # of every processing loop.
    s.setCallback(process)

    s.gui(locals())