2015-04-19.

E.g.:  normal speed, but lower pitch, 
  mplayer -af scaletempo=scale=1.0:speed=pitch -speed 0.8  FILE

(that was from: http://superuser.com/questions/631036/how-to-change-pitch-of-music-in-mplayer )

From: 
  https://markplusplus.wordpress.com/2006/10/01/pitch-correct-play-speed-with-mplayer/
using LADSPA (which isn't on this Scientific Linux + extras installation, 
 mplayer -speed 1.5 -af ladspa=tap_pitch:tap_pitch:0:-33:-90:0  FILE 
 mplayer -speed 0.5 -af ladspa=tap_pitch:tap_pitch:0:100:-90:0  FILE