XP Codec Pack is a complete package containing the most requested codecs, both audio and video. So you don't have to use multiple different players to play all kinds of formats. The program comes with Media Player Classic.
The program has: AC3Filter, AVI Splitter, CDXA Reader, CoreAAC, CoreFlac Decoder, FFDShow MPEG-4 Video Decoder, GPL MPEG-1/2 Decoder, Matroska Splitter, Media Player Classic, OggSplitter/CoreVorbis, RadLight APE Filter, RadLight MPC Filter , RadLight OFR Filter, RealMedia Splitter, RadLight TTA Filter, VSFilter (DirectVobSub).