def longest_bar_len(bars_in_frames):
    """
    DEPRECATED
    Returns the size of the longest bar among all, in number of frames.

    Parameters
    ----------
    bars_in_frames : list of tuples of integers
        The bars, as tuples (start, end), in number of frames.

    Returns
    -------
    max_len : integer
        The size of the longest bar.
    """
    max_len = 0
    for bar in bars_in_frames:
        if bar[1] - bar[0] > max_len:
            max_len = bar[1] - bar[0]
    return max_len