The default value of @var{x} and @var{y} is 0.
+If @var{x} or @var{y} evaluate to a negative number, they'll be changed
+so the input image is centered on the padded area.
+
@item color
Specify the color of the padded area. For the syntax of this option,
check the "Color" section in the ffmpeg-utils manual.
Default value is @samp{init}.
+@item aspect
+Pad to aspect instead to a resolution.
+
@end table
The value for the @var{width}, @var{height}, @var{x}, and @var{y}