The Mplayer codec status page has the complete list and is updated daily.

 

Mplayer Supported Input Formats

• (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
• Matroska
• NUT
• NSV (Nullsoft Streaming Video)
• VIVO format
• FLI format
• NuppelVideo format
• yuv4mpeg format
• FILM (.cpk) format
• RoQ format
• PVA format
• streaming via HTTP/FTP, RTP/RTSP, MMS/MMST, MPST, SDP

Supported Video 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

Supported Audio codecs

• 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), ALAC
• Ogg Vorbis audio
• VIVO audio (g723, Vivo Siren) (using x86 DLL)
• alaw/ulaw, (ms)gsm, pcm, *adpcm and other simple old audio formats