also handle out-of-threshold reference in single channels only

"""

import logging

import warnings

import math

import multiprocessing as mp

import platform

        ss.append(ss_seg)

    if np.all(segment_counter == 0):

        # the reference signal was outside of [thresh_lowm thresh_high] for all segments -> return -inf

        # note that this is not in line with the mpeg conf tool which gives +/-0.0 in this case

        ssnr = np.asarray([-np.inf] * len(segment_counter))

    else:

        # round to 2 decimals. this is just to be in line with the mpeg conformance tool

    # if the reference signal was outside the thresholds for all segments in a channel, segment_counter is zero

    # for that channel and the division here would trigger a warning. We supress the warning and later

    # set the SSNr for those channels to -inf manually instead (overwriting later is simply easier than adding ifs here)

    with warnings.catch_warnings():

        ssnr = np.round(10 * np.log10(10 ** (np.sum(ss, axis=0) / segment_counter) - 1), 2)

    ssnr[segment_counter == 0] = -np.inf

    return ssnr