def extract_channel_events(channel, maxdur=0.012, thresh=0.2, samplerate=44100
    ):
    """From a single channel, extract events that reach *thresh*old and last
    for *maxdur*"""
    events = []
    lastevt = -20000
    for index, value in enumerate(channel):
        if index - lastevt > maxdur * samplerate:
            if abs(value) > thresh:
                events.append(index / samplerate)
                lastevt = index
    return events
