lavfi/pad: add support to named options

1 files changed, 45 insertions, 37 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 5718d100b7..442fe35466 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3725,14 +3725,50 @@ testsrc=s=100x100, split=4 [in0][in1][in2][in3];
 
 @section pad
 
-Add paddings to the input image, and places the original input at the
+Add paddings to the input image, and place the original input at the
 given coordinates @var{x}, @var{y}.
 
-It accepts the following parameters:
+The filter accepts parameters as a list of @var{key}=@var{value} pairs,
+separated by ":".
+
+If the key of the first options is omitted, the arguments are
+interpreted according to the syntax
 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
 
-The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
-expressions containing the following constants:
+A description of the accepted options follows.
+
+@table @option
+@item width, w
+@item height, h
+Specify an expression for the size of the output image with the
+paddings added. If the value for @var{width} or @var{height} is 0, the
+corresponding input size is used for the output.
+
+The @var{width} expression can reference the value set by the
+@var{height} expression, and vice versa.
+
+The default value of @var{width} and @var{height} is 0.
+
+@item x
+@item y
+Specify an expression for the offsets where to place the input image
+in the padded area with respect to the top/left border of the output
+image.
+
+The @var{x} expression can reference the value set by the @var{y}
+expression, and vice versa.
+
+The default value of @var{x} and @var{y} is 0.
+
+@item color
+Specify the color of the padded area, it can be the name of a color
+(case insensitive match) or a 0xRRGGBB[AA] sequence.
+
+The default value of @var{color} is "black".
+@end table
+
+The value for the @var{width}, @var{height}, @var{x}, and @var{y}
+options are expressions containing the following constants:
 
 @table @option
 @item in_w, in_h
@@ -3766,39 +3802,6 @@ horizontal and vertical chroma subsample values. For example for the
 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
 @end table
 
-Follows the description of the accepted parameters.
-
-@table @option
-@item width, height
-
-Specify the size of the output image with the paddings added. If the
-value for @var{width} or @var{height} is 0, the corresponding input size
-is used for the output.
-
-The @var{width} expression can reference the value set by the
-@var{height} expression, and vice versa.
-
-The default value of @var{width} and @var{height} is 0.
-
-@item x, y
-
-Specify the offsets where to place the input image in the padded area
-with respect to the top/left border of the output image.
-
-The @var{x} expression can reference the value set by the @var{y}
-expression, and vice versa.
-
-The default value of @var{x} and @var{y} is 0.
-
-@item color
-
-Specify the color of the padded area, it can be the name of a color
-(case insensitive match) or a 0xRRGGBB[AA] sequence.
-
-The default value of @var{color} is "black".
-
-@end table
-
 @subsection Examples
 
 @itemize
@@ -3810,6 +3813,11 @@ column 0, row 40:
 pad=640:480:0:40:violet
 @end example
 
+The example above is equivalent to the following command:
+@example
+pad=width=640:height=480:x=0:y=40:color=violet
+@end example
+
 @item
 Pad the input to get an output with dimensions increased by 3/2,
 and put the input video at the center of the padded area: