MPlayer has a fully configurable, command-driven control layer which allows you to control MPlayer using keyboard. Below is a list of mostly used MPlayer keyboard control. They comes from the mplayer manual, you can get it by “man mplayer”. But a web page may be more convenient.

Mplayer keyboard control:
    < - and ->
      Seek backward/forward 10 seconds.
    up and down
      Seek forward/backward 1 minute.
    pgup and pgdown
      Seek forward/backward 10 minutes.
    [ and ]
      Decrease/increase current playback speed by 10%.
    { and }
      Halve/double current playback speed.
    backspace
      Reset playback speed to normal.
    < and >
      Go backward/forward in the playlist.
    enter
      go forward in the playlist, even over the end.
    home and end
      next/previous playtree entry in the parent list
    ins and del (asx playlist only)
      next/previous alternative source.
    p / space
      pause (pressing again unpauses).
    .
      step forward. pressing once will pause movie, every con-
      secutive press will play one frame and then go into pause
      mode again (any other key unpauses).
    q / esc
      stop playing and quit.
    u
      stop playing (and quit if -idle is not used).
    + and -
      adjust audio delay by +/- 0.1 seconds.
    / and *
      decrease/increase volume.
    9 and 0
      decrease/increase volume.
    ( and )
      adjust audio balance in favor of left/right channel.
    m
      mute sound.
    _ (mpeg-ts, avi and libavformat only)
      cycle through the available video tracks.
    # (dvd, mpeg, matroska, avi and libavformat only)
      cycle through the available audio tracks.
    tab (mpeg-ts and libavformat only)
      cycle through the available programs.
    f
      toggle fullscreen (also see -fs).
    t
      toggle stay-on-top (also see -ontop).
    w and e
      decrease/increase pan-and-scan range.
    o
      toggle osd states: none / seek / seek + timer / seek +
      timer + total time.
    d
      toggle frame dropping states: none / skip display / skip
      decoding (see -framedrop and -hardframedrop).
    v
      toggle subtitle visibility.
    j
      cycle through the available subtitles.
    y and g
      step forward/backward in the subtitle list.
    f
      toggle displaying "forced subtitles".
    a
      toggle subtitle alignment: top / middle / bottom.
    x and z
      adjust subtitle delay by +/- 0.1 seconds.
    r and t
      move subtitles up/down.
    i (-edlout mode only)
      set start or end of an edl skip and write it out to the
      given file.
    s (-vf screenshot only)
      take a screenshot.
    s (-vf screenshot only)
      start/stop taking screenshots.
    i
      show filename on the osd.
    ! and @
      seek to the beginning of the previous/next chapter.
    d (-vo xvmc, -vo vdpau, -vf yadif, -vf kerndeint only)
      activate/deactivate deinterlacer.
    a  cycle through the available dvd angles.

    (the following keys are valid only when using a hardware accel-
    erated video output (xv, (x)vidix, (x)mga, etc), the software
    equalizer (-vf eq or -vf eq2) or hue filter (-vf hue).)

    1 and 2
      adjust contrast.
    3 and 4
      adjust brightness.
    5 and 6
      adjust hue.
    7 and 8
      adjust saturation.

    (the following keys are only valid if gui support is compiled in
    and will take precedence over the keys defined above.)

    enter
      start playing.
    esc
      stop playing.
    l
      load file.
    t
      load subtitle.
    c
      open skin browser.
    p
      open playlist.
    r
      open preferences.

Read more:

• Useful Mplayer/Mencoder Commands
• MPlayer on Fedora
• Convert movie file to wav and mp3 file using mplayer and lame
• MPlayer startup volume and postion
• How to wrap and NOT wrap lines in vim
• vim tips