or maybe monster regexp?

gistfile1.txt

    matcher = re.compile(r'''^
        (?:(?P<prefix>\[.*\])\s+)?
        (?P<name>.+?)
        ([._ ](?P<year>[0-9]{4}))?
        ([. ]
            (?:(
                [Ss](?P<season>[0-9]+)
                (
                    [Ee](?P<episode>[0-9]+)
                )?
            )|(
                (?P<season_a>[0-9]+)x(?P<episode_a>[0-9]+)
            )|(
                (?P<special>
                    (?:Christmas.Special.[0-9]{4})|
                    (?:[0-9]{4}.Christmas.Special)|
                    (?:[0-9]{2}th.Anniversary.Special)|
                    (?:Special)
                )
                [._]?
            ))
            (?P<episode_name>.*?)
        )?
        (?P<moviepack>MOViE.PACK|Movie.Pack)?
        (?:
            \[(?P<tagsb>[^\]]*)\]|
            (?P<tags>
                (?:[._ ]?
                    (?:
                    [xX]264|
                    [0-9]{3,4}p|
                    [0-9]{4}|
                    AC3|
                    DTS|
                    HDTV|
                    PDTV|
                    BluRay|
                    BRRip|
                    DVDRip|
                    XviD|
                    XVID|
                    DD5\.1|
                    3D)
                )+
                (?:[.]
                    (?:[a-zA-Z0-9]{1,5})
                )*
            )
        )?
        (
            \.avi|
            _?-_?(?P<group>[^-]{2,18})|
            \s?{(?P<groupb>.*)}|
            \s[A-Zi]+
        )$
    ''', re.VERBOSE).match