lavfi/fieldorder: add support to named options

doc/filters.texi

@@ -2986,18 +2986,19 @@ field=type=bottom
 
 Transform the field order of the input video.
 
-It accepts one parameter which specifies the required field order that
-the input interlaced video will be transformed to. The parameter can
-assume one of the following values:
+This filter accepts the named option @option{order} which
+specifies the required field order that the input interlaced video
+will be transformed to. The option name can be omitted.
 
-@table @option
-@item 0 or bff
+The option @option{order} can assume one of the following values:
+@table @samp
+@item bff
 output bottom field first
-@item 1 or tff
+@item tff
 output top field first
 @end table
 
-Default value is "tff".
+Default value is @samp{tff}.
 
 Transformation is achieved by shifting the picture content up or down
 by one line, and filling the remaining line with appropriate picture content.

libavfilter/version.h

@@ -30,7 +30,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR  3
 #define LIBAVFILTER_VERSION_MINOR  45
-#define LIBAVFILTER_VERSION_MICRO 100
+#define LIBAVFILTER_VERSION_MICRO 101
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_fieldorder.c

@@ -23,6 +23,7 @@
  * video field order filter, heavily influenced by vf_pad.c
  */
 
+#include "libavutil/opt.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/internal.h"
 #include "libavutil/pixdesc.h"
@@ -31,34 +32,45 @@
 #include "internal.h"
 #include "video.h"
 
-typedef struct
-{
+enum FieldOrder {
+    ORDER_TFF,
+    ORDER_BFF,
+    ORDER_NB,
+};
+
+typedef struct {
+    const AVClass *class;
+    enum FieldOrder order;
     unsigned int dst_tff;      ///< output bff/tff
     int          line_size[4]; ///< bytes of pixel data per line for each plane
 } FieldOrderContext;
 
+#define OFFSET(x) offsetof(FieldOrderContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption fieldorder_options[] = {
+    { "order", "set output field order", OFFSET(order), AV_OPT_TYPE_INT, {.i64=ORDER_TFF}, 0, ORDER_NB-1, FLAGS, "order" },
+    { "tff",   "set top field first",    0, AV_OPT_TYPE_CONST, {.i64=ORDER_TFF}, .flags=FLAGS, .unit="order" },
+    { "bff",   "set bottom field first", 0, AV_OPT_TYPE_CONST, {.i64=ORDER_BFF}, .flags=FLAGS, .unit="order" },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(fieldorder);
+
 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     FieldOrderContext *fieldorder = ctx->priv;
+    int ret;
+    static const char *shorthand[] = { "order", NULL };
 
-    const char *tff = "tff";
-    const char *bff = "bff";
-
-    if (!args) {
-        fieldorder->dst_tff = 1;
-    } else if (sscanf(args, "%u", &fieldorder->dst_tff) == 1) {
-        fieldorder->dst_tff = !!fieldorder->dst_tff;
-    } else if (!strcmp(tff, args)) {
-        fieldorder->dst_tff = 1;
-    } else if (!strcmp(bff, args)) {
-        fieldorder->dst_tff = 0;
-    } else {
-        av_log(ctx, AV_LOG_ERROR, "Invalid argument '%s'.\n", args);
-        return AVERROR(EINVAL);
-    }
+    fieldorder->class = &fieldorder_class;
+    av_opt_set_defaults(fieldorder);
+
+    if ((ret = av_opt_set_from_string(fieldorder, args, shorthand, "=", ":")) < 0)
+        return ret;
 
-    av_log(ctx, AV_LOG_VERBOSE, "output field order: %s\n",
-            fieldorder->dst_tff ? tff : bff);
+    fieldorder->dst_tff = fieldorder->order == ORDER_TFF;
+    av_log(ctx, AV_LOG_VERBOSE, "tff:%d\n", fieldorder->dst_tff);
 
     return 0;
 }
@@ -200,4 +212,5 @@ AVFilter avfilter_vf_fieldorder = {
     .query_formats = query_formats,
     .inputs        = avfilter_vf_fieldorder_inputs,
     .outputs       = avfilter_vf_fieldorder_outputs,
+    .priv_class    = &fieldorder_class,
 };