lavfi/settb: add support for named options

doc/filters.texi

@@ -6618,12 +6618,14 @@ ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
 Set the timebase to use for the output frames timestamps.
 It is mainly useful for testing timebase configuration.
 
-It accepts in input an arithmetic expression representing a rational.
-The expression can contain the constants "AVTB" (the
-default timebase), "intb" (the input timebase) and "sr" (the sample rate,
-audio only).
-
-The default value for the input is "intb".
+This filter accepts a single option @option{tb}, which can be
+specified either by setting @option{tb}=@var{VALUE} or setting the
+value alone.
+
+The value for @option{tb} is an arithmetic expression representing a
+rational. The expression can contain the constants "AVTB" (the default
+timebase), "intb" (the input timebase) and "sr" (the sample rate,
+audio only). Default value is "intb".
 
 @subsection Examples
 

libavfilter/f_settb.c

@@ -30,6 +30,7 @@
 #include "libavutil/eval.h"
 #include "libavutil/internal.h"
 #include "libavutil/mathematics.h"
+#include "libavutil/opt.h"
 #include "libavutil/rational.h"
 #include "avfilter.h"
 #include "internal.h"
@@ -51,21 +52,40 @@ enum var_name {
 };
 
 typedef struct {
-    char tb_expr[256];
+    const AVClass *class;
+    char *tb_expr;
     double var_values[VAR_VARS_NB];
 } SetTBContext;
 
-static av_cold int init(AVFilterContext *ctx, const char *args)
+#define OFFSET(x) offsetof(SetTBContext, x)
+#define DEFINE_OPTIONS(filt_name, filt_type)                                               \
+static const AVOption filt_name##_options[] = {                                            \
+    { "tb", "set timebase expression", OFFSET(tb_expr), AV_OPT_TYPE_STRING, {.str="intb"}, \
+           .flags=AV_OPT_FLAG_##filt_type##_PARAM|AV_OPT_FLAG_FILTERING_PARAM },           \
+    { NULL }                                                                               \
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args, const AVClass *class)
 {
     SetTBContext *settb = ctx->priv;
-    av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
+    static const char *shorthand[] = { "tb", NULL };
+    int ret;
 
-    if (args)
-        sscanf(args, "%255[^:]", settb->tb_expr);
+    settb->class = class;
+    av_opt_set_defaults(settb);
+
+    if ((ret = av_opt_set_from_string(settb, args, shorthand, "=", ":")) < 0)
+        return ret;
 
     return 0;
 }
 
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    SetTBContext *settb = ctx->priv;
+    av_opt_free(settb);
+}
+
 static int config_output_props(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
@@ -120,6 +140,15 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 }
 
 #if CONFIG_SETTB_FILTER
+
+DEFINE_OPTIONS(settb, VIDEO);
+AVFILTER_DEFINE_CLASS(settb);
+
+static av_cold int settb_init(AVFilterContext *ctx, const char *args)
+{
+    return init(ctx, args, &settb_class);
+}
+
 static const AVFilterPad avfilter_vf_settb_inputs[] = {
     {
         .name             = "default",
@@ -142,16 +171,27 @@ static const AVFilterPad avfilter_vf_settb_outputs[] = {
 AVFilter avfilter_vf_settb = {
     .name      = "settb",
     .description = NULL_IF_CONFIG_SMALL("Set timebase for the video output link."),
-    .init      = init,
+    .init      = settb_init,
+    .uninit    = uninit,
 
     .priv_size = sizeof(SetTBContext),
 
     .inputs    = avfilter_vf_settb_inputs,
     .outputs   = avfilter_vf_settb_outputs,
+    .priv_class = &settb_class,
 };
 #endif
 
 #if CONFIG_ASETTB_FILTER
+
+DEFINE_OPTIONS(asettb, AUDIO);
+AVFILTER_DEFINE_CLASS(asettb);
+
+static av_cold int asettb_init(AVFilterContext *ctx, const char *args)
+{
+    return init(ctx, args, &asettb_class);
+}
+
 static const AVFilterPad avfilter_af_asettb_inputs[] = {
     {
         .name             = "default",
@@ -174,10 +214,12 @@ static const AVFilterPad avfilter_af_asettb_outputs[] = {
 AVFilter avfilter_af_asettb = {
     .name      = "asettb",
     .description = NULL_IF_CONFIG_SMALL("Set timebase for the audio output link."),
-    .init      = init,
+    .init      = asettb_init,
+    .uninit    = uninit,
 
     .priv_size = sizeof(SetTBContext),
     .inputs    = avfilter_af_asettb_inputs,
     .outputs   = avfilter_af_asettb_outputs,
+    .priv_class = &asettb_class,
 };
 #endif

libavfilter/version.h

@@ -30,7 +30,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR  3
 #define LIBAVFILTER_VERSION_MINOR  47
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MICRO 102
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \