./mplayer2 -vo help
MPlayer2 2.0-276-gd6890a7 (C) 2000-2011 MPlayer Team
Available video output drivers:
    xv    X11/Xv
    gl_nosw    OpenGL no software rendering
    x11    X11 ( XImage/Shm )
    xover    General X11 driver for overlay capable video output drivers
    sdl    SDL YUV/RGB/BGR renderer (SDL v1.1.7+ only!)
    gl    OpenGL
    gl2    X11 (OpenGL) - multiple textures version
    dga    DGA ( Direct Graphic Access V2.0 )
    ggi    General Graphics Interface (GGI) output
    fbdev    Framebuffer Device
    fbdev2    Framebuffer Device
    svga    SVGAlib
    matrixview    MatrixView (OpenGL)
    aa    AAlib
    caca    libcaca
    v4l2    V4L2 MPEG Video Decoder Output
    dfbmga    DirectFB / Matrox G200/G400/G450/G550
    null    Null video output
    directfb    Direct Framebuffer Device
    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