lavfi/cropdetect: add support for named options

doc/filters.texi

@@ -2190,27 +2190,30 @@ Calculate necessary cropping parameters and prints the recommended
 parameters through the logging system. The detected dimensions
 correspond to the non-black area of the input video.
 
-It accepts the syntax:
-@example
-cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
-@end example
+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
+[@option{limit}[:@option{round}[:@option{reset}]]].
+
+A description of the accepted options follows.
 
 @table @option
 
 @item limit
-Threshold, which can be optionally specified from nothing (0) to
-everything (255), defaults to 24.
+Set higher black value threshold, which can be optionally specified
+from nothing (0) to everything (255). An intensity value greater
+to the set value is considered non-black. Default value is 24.
 
 @item round
-Value which the width/height should be divisible by, defaults to
-16. The offset is automatically adjusted to center the video. Use 2 to
-get only even dimensions (needed for 4:2:2 video). 16 is best when
-encoding to most video codecs.
+Set the value for which the width/height should be divisible by. The
+offset is automatically adjusted to center the video. Use 2 to get
+only even dimensions (needed for 4:2:2 video). 16 is best when
+encoding to most video codecs. Default value is 16.
 
 @item reset
-Counter that determines after how many frames cropdetect will reset
-the previously detected largest video area and start over to detect
-the current optimal crop area. Defaults to 0.
+Set the counter that determines after how many frames cropdetect will
+reset the previously detected largest video area and start over to
+detect the current optimal crop area. Default value is 0.
 
 This can be useful when channel logos distort the video area. 0
 indicates never reset and return the largest area encountered during

libavfilter/version.h

@@ -30,7 +30,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR  3
 #define LIBAVFILTER_VERSION_MINOR  45
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MICRO 102
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_cropdetect.c

@@ -23,16 +23,16 @@
  * Ported from MPlayer libmpcodecs/vf_cropdetect.c.
  */
 
-#include <stdio.h>
-
 #include "libavutil/imgutils.h"
 #include "libavutil/internal.h"
+#include "libavutil/opt.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 typedef struct {
+    const AVClass *class;
     int x1, y1, x2, y2;
     int limit;
     int round;
@@ -41,6 +41,18 @@ typedef struct {
     int max_pixsteps[4];
 } CropDetectContext;
 
+#define OFFSET(x) offsetof(CropDetectContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption cropdetect_options[] = {
+    { "limit", "set black threshold", OFFSET(limit), AV_OPT_TYPE_INT, {.i64=24}, 0, 255, FLAGS },
+    { "round", "set width/height round value", OFFSET(round), AV_OPT_TYPE_INT, {.i64=16}, 0, INT_MAX, FLAGS },
+    { "reset_count", "set after how many frames to reset detected info",  OFFSET(reset_count), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(cropdetect);
+
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
@@ -86,14 +98,15 @@ static int checkline(void *ctx, const unsigned char *src, int stride, int len, i
 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     CropDetectContext *cd = ctx->priv;
+    static const char *shorthand[] = { "limit", "round", "reset_count", NULL };
+    int ret;
 
-    cd->limit = 24;
-    cd->round = 0;
-    cd->reset_count = 0;
     cd->frame_nb = -2;
+    cd->class = &cropdetect_class;
+    av_opt_set_defaults(cd);
 
-    if (args)
-        sscanf(args, "%d:%d:%d", &cd->limit, &cd->round, &cd->reset_count);
+    if ((ret = av_opt_set_from_string(cd, args, shorthand, "=", ":")) < 0)
+        return ret;
 
     av_log(ctx, AV_LOG_VERBOSE, "limit:%d round:%d reset_count:%d\n",
            cd->limit, cd->round, cd->reset_count);
@@ -101,6 +114,12 @@ static av_cold int init(AVFilterContext *ctx, const char *args)
     return 0;
 }
 
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    CropDetectContext *cd = ctx->priv;
+    av_opt_free(cd);
+}
+
 static int config_input(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
@@ -221,10 +240,9 @@ AVFilter avfilter_vf_cropdetect = {
 
     .priv_size = sizeof(CropDetectContext),
     .init      = init,
-
+    .uninit    = uninit,
     .query_formats = query_formats,
-
     .inputs    = avfilter_vf_cropdetect_inputs,
-
     .outputs   = avfilter_vf_cropdetect_outputs,
+    .priv_class = &cropdetect_class,
 };