MPlayer is a movie player for Linux (runs on many other Unices, and non-x86 CPUs, see the documentation). MPlayer plays most MPEG, VOB, AVI, Ogg/OGM, VIVO, ASF/WMA/WMV, QT/MOV/MP4, FLI, RM, NuppelVideo, YUV4MPEG, FILM, RoQ, PVA files, supported by many native, XAnim, and Win32 DLL codecs. You can watch VideoCD, SVCD, DVD, 3ivx, DivX 3/4/5 and even WMV movies, too (without the avifile library).
Another great feature of MPlayer is the wide range of supported output drivers. It works with X11, Xv, DGA, OpenGL, SVGAlib, fbdev, AAlib, DirectFB, but you can use GGI, SDL (and this way all their drivers), VESA (on every VESA compatible card, even without X11!) and some low level card-specific drivers (for Matrox, 3Dfx and ATI), too!
Most of them support software or hardware scaling, so you can enjoy movies in fullscreen. MPlayer supports displaying through some hardware MPEG decoder boards, such as the Siemens DVB, DXR2 and DXR3/Hollywood+.
MPlayer has an onscreen display (OSD) for status information, nice big antialiased shaded subtitles and visual feedback for keyboard controls. European/ISO 8859-1,2 (Hungarian, English, Czech, etc), Cyrillic and Korean fonts are supported along with 12 subtitle formats (MicroDVD, SubRip, OGM, SubViewer, Sami, VPlayer, RT, SSA, AQTitle, JACOsub, PJS and our own: MPsub). DVD subtitles (SPU streams, VOBsub and Closed Captions) are supported as well.
Here are some key features of "Mplayer":
(S)VCD (Super Video CD)
CDRwin's .bin image file
DVD, including encrypted DVD
MPEG-1/2 (ES/PS/PES/VOB)
RIFF AVI file format
ASF/WMV/WMA format
QT/MOV/
mp4 format
RealAudio/RealVideo format
Ogg/OGM files
VIVO format
FLI format
NuppelVideo format
yuv4mpeg format
FILM (.cpk) format
RoQ format
PVA format
Matroska
NSV - Nullsoft Streaming Video
streaming via http, RTP, RTSP, mms, mmst, mpst, sdp
TV
Supported Video and Audio Codecs:
MPEG-1 (VCD) and MPEG-2 (SVCD/DVD/DVB) video
MPEG-4 in all variants including DivX ;-), OpenDivX (DivX4), DivX 5 (Pro), XviD
Windows Media Video 7/8 (WMV1/2)
Windows Media Video 9 (WMV3) (using x86 DLL)
RealVideo 1.0, 2.0 (G2)
RealVideo 3.0 (RP8), 4.0 (RP9) (using Real libraries)
Sorenson v1/v3 (SVQ1/SVQ3), Cinepak, RPZA and other QuickTime codecs
DV video
3ivx
Intel Indeo3 (3.1, 3.2)
Intel Indeo 4.1 and 5.0 (using x86 DLL or XAnim codecs)
VIVO 1.0, 2.0, I263 and other H.263(+) variants (using x86 DLL)
MJPEG, AVID, VCR2, ASV2 and other hardware formats
FLI/FLC
HuffYUV
various old simple RLE-like formats
MPEG layer 1, 2, and 3 (MP3) audio
AC3/A52 (Dolby Digital) audio (software or SP/DIF)
AAC (MPEG-4 audio)
WMA (DivX Audio) v1, v2
WMA 9 (WMAv3), Voxware audio, ACELP.net etc (using x86 DLLs)
RealAudio: COOK, SIPRO, ATRAC3 (using Real libraries)
RealAudio: DNET and older codecs
QuickTime: Qclp, Q-Design QDMC/QDM2, MACE 3/6 (using QT libraries)
Ogg Vorbis audio
VIVO audio (g723, Vivo Siren) (using x86 DLL)
alaw/ulaw, (ms)gsm, pcm, *adpcm and other simple old audio format
MP4 Converter
7.80 MB 
$ 49.95