librosa/display.py
def __envelope(x, hop):
    '''Compute the max-envelope of x at a stride/frame length of h'''
    return util.frame(x, hop_length=hop, frame_length=hop).max(axis=0)
def __envelope(x, hop):
    '''Compute the max-envelope of x at a stride/frame length of h'''
    return util.frame(x, hop_length=hop, frame_length=hop).max(axis=0)
Compute the max-envelope of x at a stride/frame length of h