Pioneer DVD-V555 Operating Insructions page 37

For DVDs where aspect switching is possible, select the aspect
that matches the TV.
Aspect
Disc
Wide TV (16:9)
selection
Wide
(16:9)
Pan
&scan
Letter
box
(4:3)
When the above chart's
correct height to width ratio will be selected. Whether aspect
can be switched or not depends on the disc. Please refer to the
information written on the disc's jacket etc.
For discs where aspect selection is not possible, make the screen
adjustment using the TV's controls.
Note
When there is a power outage, the power is turned off during
playback, with the STANDBY/ON button on the main unit or you
disconnect the player from the wall outlet while the power is
ON, settings are cleared. Before disconnecting the power cord,
press the STANDBY/ON button on the remote control to enter
the unit to standby mode after distinguishing the "– OFF –"
display, then press the STANDBY/ON button on the main unit.
Tips
¶ The width-to-height ratio of conventional TVs is 4:3, while the
width-to-height ratio of wide screen and Hi-Vision TVs is 16:9.
This width-to-height ratio is called the aspect ratio.
Multi-Aspect Setting for Wide Screen TV Software
Regular TV (4:3)
is selected, the picture with the
Multi-Aspect Setting for Wide
Screen TV Software
37
<VRB1210>