@@ -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:

@@ -30,7 +30,7 @@

 #define LIBAVFILTER_VERSION_MAJOR  3

 #define LIBAVFILTER_VERSION_MINOR  35

-#define LIBAVFILTER_VERSION_MICRO 100

+#define LIBAVFILTER_VERSION_MICRO 101

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

                                                LIBAVFILTER_VERSION_MINOR, \

@@ -35,6 +35,7 @@

 #include "libavutil/colorspace.h"

 #include "libavutil/avassert.h"

 #include "libavutil/imgutils.h"

+#include "libavutil/opt.h"

 #include "libavutil/parseutils.h"

 #include "libavutil/mathematics.h"

 #include "drawutils.h"

@@ -76,40 +77,61 @@ static int query_formats(AVFilterContext *ctx)

 }

 typedef struct {

+    const AVClass *class;

     int w, h;               ///< output dimensions, a value of 0 will result in the input size

     int x, y;               ///< offsets of the input area with respect to the padded area

     int in_w, in_h;         ///< width and height for the padded input video, which has to be aligned to the chroma values in order to avoid chroma issues

-    char w_expr[256];       ///< width  expression string

-    char h_expr[256];       ///< height expression string

-    char x_expr[256];       ///< width  expression string

-    char y_expr[256];       ///< height expression string

-

+    char *w_expr;       ///< width  expression string

+    char *h_expr;       ///< height expression string

+    char *x_expr;       ///< width  expression string

+    char *y_expr;       ///< height expression string

+    char *color_str;

     uint8_t rgba_color[4];  ///< color for the padding area

     FFDrawContext draw;

     FFDrawColor color;

 } PadContext;

+#define OFFSET(x) offsetof(PadContext, x)

+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

+

+static const AVOption pad_options[] = {

+    { "width",  "set the pad area width expression",       OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "w",      "set the pad area width expression",       OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "height", "set the pad area height expression",      OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "h",      "set the pad area height expression",      OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "x",      "set the x offset expression for the input image position", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "0"}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "y",      "set the y offset expression for the input image position", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "0"}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "color",  "set the color of the padded area border", OFFSET(color_str), AV_OPT_TYPE_STRING, {.str = "black"}, .flags = FLAGS },

+    {NULL}

+};

+

+AVFILTER_DEFINE_CLASS(pad);

+

 static av_cold int init(AVFilterContext *ctx, const char *args)

 {

     PadContext *pad = ctx->priv;

-    char color_string[128] = "black";

+    static const char *shorthand[] = { "width", "height", "x", "y", "color", NULL };

+    int ret;

-    av_strlcpy(pad->w_expr, "iw", sizeof(pad->w_expr));

-    av_strlcpy(pad->h_expr, "ih", sizeof(pad->h_expr));

-    av_strlcpy(pad->x_expr, "0" , sizeof(pad->w_expr));

-    av_strlcpy(pad->y_expr, "0" , sizeof(pad->h_expr));

+    pad->class = &pad_class;

+    av_opt_set_defaults(pad);

-    if (args)

-        sscanf(args, "%255[^:]:%255[^:]:%255[^:]:%255[^:]:%127s",

-               pad->w_expr, pad->h_expr, pad->x_expr, pad->y_expr, color_string);

+    if ((ret = av_opt_set_from_string(pad, args, shorthand, "=", ":")) < 0)

+        return ret;

-    if (av_parse_color(pad->rgba_color, color_string, -1, ctx) < 0)

+    if (av_parse_color(pad->rgba_color, pad->color_str, -1, ctx) < 0)

         return AVERROR(EINVAL);

     return 0;

 }

+static av_cold void uninit(AVFilterContext *ctx)

+{

+    PadContext *pad = ctx->priv;

+    av_opt_free(pad);

+}

+

 static int config_input(AVFilterLink *inlink)

 {

     AVFilterContext *ctx = inlink->dst;

@@ -368,9 +390,11 @@ AVFilter avfilter_vf_pad = {

     .priv_size     = sizeof(PadContext),

     .init          = init,

+    .uninit        = uninit,

     .query_formats = query_formats,

     .inputs    = avfilter_vf_pad_inputs,

     .outputs   = avfilter_vf_pad_outputs,

+    .priv_class = &pad_class,

 };