$ mplayer -vo help
MPlayer 1.0rc1-4.1.2 (C) 2000-2006 MPlayer Team
CPU: AMD Athlon(tm) XP 2200+ (Family: 6, Model: 8, Stepping: 1)
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 0
Compiled with runtime CPU detection.
Available video output drivers:
        xv      X11/Xv
        x11     X11 ( XImage/Shm )
        xover   General X11 driver for overlay capable video output drivers
        gl      X11 (OpenGL)
        gl2     X11 (OpenGL) - multiple textures version
        dga     DGA ( Direct Graphic Access V2.0 )
        sdl     SDL YUV/RGB/BGR renderer (SDL v1.1.7+ only!)
        fbdev   Framebuffer Device
        fbdev2  Framebuffer Device
        aa      AAlib
        caca    libcaca
        xvidix  X11 (VIDIX)
        cvidix  console VIDIX
        null    Null video output
        mpegpes Mpeg-PES to DVB card
        yuv4mpeg        yuv4mpeg output for mjpegtools
        png     PNG file
        jpeg    JPEG file
        gif89a  animated GIF output
        tga     Targa output
        pnm     PPM/PGM/PGMYUV file
        md5sum  md5sum of each frame

98 audio & 216 video codecs