@table @option
@item width, w
-Output video width.
-default value is @code{iw}. See below
-for the list of accepted constants.
+Set the output video width expression. Default value is @code{iw}. See
+below for the list of accepted constants.
@item height, h
-Output video height.
-default value is @code{ih}.
+Set the output video height expression. Default value is @code{ih}.
See below for the list of accepted constants.
@item interl