Here are some codecs and filters you may need wehn playing amvs and other video

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FFDShow MPEG-4 Video Decoder

http://www.free-codecs.com/download/FFDShow.htm/

Divx

http://www.free-codecs.com/download/DivX6.htm

Xvid

http://www.free-codecs.com/download/Koepi_XviD.htm

Ogg DirectShow Filters

http://www.free-codecs.com/download/Ogg_DirectShow_Filters.htm

Xvid

http://www.free-codecs.com/download/Koepi_XviD.htm

MKV Video Filter

http://packs.matroska.org/

x264 Video Codec

http://www.free-codecs.com/download/x264_Video_Codec.htm