Specify which channels to filter, by default all available are filtered.
@end table
+@subsection Examples
+@itemize
+@item
+Lowpass only LFE channel, it LFE is not present it does nothing:
+@example
+lowpass=c=LFE
+@end example
+@end itemize
+
@anchor{pan}
@section pan
can be used to test the monowhite pixel format descriptor definition.
+@section pixscope
+
+Display sample values of color channels. Mainly useful for checking color and levels.
+
+The filters accept the following options:
+
+@table @option
+@item x
+Set scope X position, offset on X axis.
+
+@item y
+Set scope Y position, offset on Y axis.
+
+@item w
+Set scope width.
+
+@item h
+Set scope height.
+
+@item o
+Set window opacity. This window also holds statistics about pixel area.
+@end table
+
@section pp
Enable the specified chain of postprocessing subfilters using libpostproc. This