[FFmpeg-devel] [PATCH] doc/filters: extend/fix documentation for the geq filter
Stefano Sabatini
stefasab at gmail.com
Sun May 19 22:56:17 CEST 2013
---
doc/filters.texi | 30 +++++++++++++++++++++---------
1 file changed, 21 insertions(+), 9 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 008699e..2cc62de 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 expressions. If
+one of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
+expression 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:
@@ -4064,6 +4070,12 @@ blue-difference chroma plane. Returns 0 if there is no such plane.
Return the value of the pixel at location (@var{x}, at var{y}) of the
red-difference chroma plane. Returns 0 if there is no such plane.
+ at item r(x, y)
+ at item g(x, y)
+ at item b(x, y)
+Return the value of the pixel at location (@var{x}, at var{y}) of the
+red/green/blue component. Returns 0 if there is no such component.
+
@item alpha(x, y)
Return the value of the pixel at location (@var{x}, at var{y}) of the alpha
plane. Returns 0 if there is no such plane.
--
1.7.9.5
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