Windows Essentials Codec Pack

With Windows Essentials Codec Pack you should be able to play 99% of all movies and music files that you download Windows Essentials Codec Pack is a collection of the most essential Audio and Video DirectShow Codecs and Filters.

With Windows Essentials Codec Pack you should be able to play 99% of all movies and music files that you download off the internet, stay up to date with the latest Codecs with the Audio / Video Codec Update Service, and eliminate the many conflicts and error caused by using multiple codecs to decode the same file types.

W.E.C.P. is designed as a user-friendly near complete solution for all your video and audio needs, with it you can play Audio CDs, DVDs, (S)VCDs and XCDs on the fly, and it adds support for 3GP, AAC, AC3, APE, AVI, DivX, 3ivx, DAT, h.264, x264, Nero Digital, DTS, FLV, FLAC, HD-MOV, MPEG-1/2, M4A, MP3, MP4, MO3, MOD, MKV, OFR, TTA, OGG/OGM, S3M, Vorbis, VOB, XviD, XM, WV, UMX and many more formats so you could play any video / audio file with your favorite DirectShow media player or with the (included) free and wonderful Media Player Classic

Here are some key features of "Windows Essentials Codec Pack":
APE Source Filter: DirectShow audio decoder filter used to decode Monkey's Audio files (APE files)
AC3 Filter: DirectShow audio decoder and processor filter used to decode audio tracks in movies (DVD, MPEG4 and others)
AVI Splitter: Replacement for DirectShow's default Audio Video Interleave (AVI) Splitter (It can open many broken files and can reindex when needed)
CDDA Reader Filter: DirectShow audio decoder capable of reading Audio CDs
CDXA Reader Filter: DirectShow video decoder capable of reading (S)VCDs and XCDs
CoreAAC Filter: Advanced Audio Coding (AAC) DirectShow audio decoder capable of reading AAC files
CoreFlac Decoder: DirectShow audio decoder for the Flac audio codec
FFDShow: DirectShow decoding filter for decompressing DivX, XviD, H.264, FLV1, WMV, MPEG-1 and MPEG-2, MPEG-4 and various other audio and video formats. It uses libavcodec from ffmpeg project for video decompression, postprocessing code from mplayer to enhance visual quality of low bitrate movies, and is based on original DirectShow filter from XviD, which is GPL'ed educational implementation of MPEG4 encoder
FLV Splitter: Capable of splitting Flash Video files (FLV) and decoding On2 VP62 Video streams (notable users of the FLV format include YouTube, Google Video, Reuters.com, Yahoo! Video and MySpace.)
OGG Splitter: DirectShow OGG Splitter capable of splitting OGG and OGM file(s) and enables to play / create .ogm wrapped video
GPL MPEG-1/2 Decoder: DirectShow MPEG decoder filter can be used to play MPEG-1 and MPEG-2 streams
MOD Source Filter: DirectShow filter decoder capable of decoding Tracker files (MO3, IT, XM, S3M, MTM, MOD and UMX)
MPEG Splitter: DirectShow splitter capable of splitting MPEG1/MPEG2 files (MP(E)G, VOB, DAT, TS, TP, etc.)
MPV Decoder: DirectShow decoder capable of decoding MPEG1/MPEG2 Video streams, and DVDs
MPA Splitter: DirectShow Splitter capable of splitting MPEG Audio files (MP3) and MPEG4 Audio files (AAC)
MPC Source Filter: DirectShow decoder filter capable of decoding MusePack Audio files (MPC).
MP4 Splitter: DirectShow Splitter capable of splitting MP4, M4A, 3GP and HD-MOV files
Matroska Splitter: DirectShow splitter capable of splitting Matroska files (MKV and MKA)
Media Player Classic: an open source media player that looks just like Windows Media Player, but has many additional features. It has a built in DVD player with real-time zoom, support for AVI subtitles, QuickTime and RealVideo support
OFR Source Filter: DirectShow filter decoder capable of decoding OptimFROG Audio files (OFR)
RealMedia Splitter: DirectShow splitter that allows you to play RealNetworks audio/video files.
SHOUTcast Source Filter: DirectShow decoder filter capable of handling internet radio stations streams (http://www.shoutcast.com)
WV Splitter / Decoder: DirectShow WV Splitter and decoder capable of splitting and decoding WavPack Audio files (WV)
VobSub Filter: DirectShow Vob Subtitles filter capable of displaying (embedded) Subtitle files (SRT, SUB, IDX, etc)