annotate vamp/__init__.py @ 56:3db99d3f2e30

Start Python module, add framer

'''A high-level interface to the vampyhost extension module, for quickly and easily running Vamp audio analysis plugins on audio files and buffers.'''

import vampyhost
import numpy

def listPlugins():
    return vampyhost.listPlugins()

def framesFromArray(arr, stepSize, frameSize):
    """Generate a list of frames of size frameSize, extracted from the input array arr at stepSize intervals"""
    # presumably such a function exists in many places, but I need practice
    assert(stepSize > 0)
    if arr.ndim == 1: # turn 1d into 2d array with 1 channel
        arr = numpy.reshape(arr, (1, arr.shape[0]))
    assert(arr.ndim == 2)
    n = arr.shape[1]
    i = 0
    while (i < n):
        frame = arr[:, i : i + frameSize]
        w = frame.shape[1]
        if (w < frameSize):
            pad = numpy.zeros((frame.shape[0], frameSize - w))
            frame = numpy.concatenate((frame, pad), 1)
        yield frame
        i = i + stepSize

def process(data, samplerate, key, parameters, outputs):
    plug = vampyhost.loadPlugin(key, samplerate, vampyhost.AdaptNone) ##!!! input domain
    stepSize = plug.getPreferredStepSize()
    blockSize = plug.getPreferredBlockSize()
    ff = framesFromArray(data, stepSize, blockSize)
    return True