Get the current movie length (in ms).
    @param p_mi: the Media Player.
    @return: the movie length (in ms), or -1 if there is no media.

def libvlc_media_player_get_length(p_mi):
    '''Get the current movie length (in ms).
    @param p_mi: the Media Player.
    @return: the movie length (in ms), or -1 if there is no media.
    '''
    f = _Cfunctions.get('libvlc_media_player_get_length', None) or \
        _Cfunction('libvlc_media_player_get_length', ((1,),), None,
                    ctypes.c_longlong, MediaPlayer)
    return f(p_mi)