DefilerPak

A minimalist collection of video and audio codecs The DefilerPak is a minimalist collection of video and audio codecs designed to keep you up to date with the latest developments

Here are some key features of "DefilerPak":
ffdshow: Rapidly making codec packs obsolete. Plays almost everything.
AC3Filter: Decodes AC-3/Dolby Digital audio streams.
CoreAAC DirectShow filter: Decodes AAC audio streams.
Ogg DirectShow filter: Enables support for .OGM containers.
CoreVorbis: Decodes Vorbis audio streams.
Matroska DirectShow filter: Supports the powerful new Matroska A/V container format.
VSFilter: Supports a wide variety of subtitle formats.
DivX ;-) Audio: Just in case.