From 281fc4e95845872b4e347099993563b8fbeacd7d Mon Sep 17 00:00:00 2001 From: Stefano Sabatini Date: Sun, 19 May 2013 22:54:27 +0200 Subject: doc/filters: extend/fix documentation for the geq filter --- doc/filters.texi | 36 ++++++++++++++++++++++++------------ 1 file changed, 24 insertions(+), 12 deletions(-) (limited to 'doc') diff --git a/doc/filters.texi b/doc/filters.texi index 008699e6e1..cc71a2f6f2 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -4004,25 +4004,31 @@ The filter accepts the following options: @table @option @item lum_expr -the luminance expression +Set the luminance expression. @item cb_expr -the chrominance blue expression +Set the chrominance blue expression. @item cr_expr -the chrominance red expression +Set the chrominance red expression. @item alpha_expr -the alpha expression +Set the alpha expression. @item r -the red expression +Set the red expression. @item g -the green expression +Set the green expression. @item b -the blue expression +Set the blue expression. @end table +The colorspace is selected according to the specified options. If +one of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr} +options is specified, the filter will automatically select a YCbCr +colorspace. If one of the @option{r}, @option{g}, or @option{b} +options is specified, it will select an RGB colorspace. + If one of the chrominance expression is not defined, it falls back on the other one. If no alpha expression is specified it will evaluate to opaque value. -If none of chrominance expressions are -specified, they will evaluate the luminance expression. +If none of chrominance expressions are specified, they will evaluate +to the luminance expression. The expressions can use the following variables and functions: @@ -4058,15 +4064,21 @@ plane. @item cb(x, y) Return the value of the pixel at location (@var{x},@var{y}) of the -blue-difference chroma plane. Returns 0 if there is no such plane. +blue-difference chroma plane. Return 0 if there is no such plane. @item cr(x, y) Return the value of the pixel at location (@var{x},@var{y}) of the -red-difference chroma plane. Returns 0 if there is no such plane. +red-difference chroma plane. Return 0 if there is no such plane. + +@item r(x, y) +@item g(x, y) +@item b(x, y) +Return the value of the pixel at location (@var{x},@var{y}) of the +red/green/blue component. Return 0 if there is no such component. @item alpha(x, y) Return the value of the pixel at location (@var{x},@var{y}) of the alpha -plane. Returns 0 if there is no such plane. +plane. Return 0 if there is no such plane. @end table For functions, if @var{x} and @var{y} are outside the area, the value will be -- cgit v1.2.3