@@ -34,9 +34,11 @@

 #include "libavutil/eval.h"

 #include "libavutil/opt.h"

 #include "libavutil/mathematics.h"

+#include "libavutil/random_seed.h"

 #include "libavutil/parseutils.h"

 #include "libavutil/pixdesc.h"

 #include "libavutil/tree.h"

+#include "libavutil/lfg.h"

 #include "avfilter.h"

 #include "drawutils.h"

@@ -62,6 +64,22 @@ static const char *var_names[] = {

     NULL

 };

+static const char *fun2_names[] = {

+    "rand",

+};

+

+static double drand(void *opaque, double min, double max)

+{

+    return val = min + (max-min) / UINT_MAX * av_lfg_get(opaque);

+}

+

+typedef double (*eval_func2)(void *, double a, double b);

+

+static const eval_func2 fun2[] = {

+    drand,

+    NULL

+};

+

 enum var_name {

     VAR_E,

     VAR_PHI,

@@ -119,6 +137,7 @@ typedef struct {

     char   *d_expr;

     AVExpr *d_pexpr;

     int draw;                       ///< set to zero to prevent drawing

+    AVLFG  prng;                    ///< random

 } DrawTextContext;

 #define OFFSET(x) offsetof(DrawTextContext, x)

@@ -559,13 +578,14 @@ static int config_input(AVFilterLink *inlink)

     dtext->var_values[VAR_N] = 0;

     dtext->var_values[VAR_T] = NAN;

+    av_lfg_init(&dtext->prng, av_get_random_seed());

     if ((ret = av_expr_parse(&dtext->x_pexpr, dtext->x_expr, var_names,

-                             NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||

+                             NULL, NULL, fun2_names, fun2, 0, ctx)) < 0 ||

         (ret = av_expr_parse(&dtext->y_pexpr, dtext->y_expr, var_names,

-                             NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||

+                             NULL, NULL, fun2_names, fun2, 0, ctx)) < 0 ||

         (ret = av_expr_parse(&dtext->d_pexpr, dtext->d_expr, var_names,

-                             NULL, NULL, NULL, NULL, 0, ctx)) < 0)

+                             NULL, NULL, fun2_names, fun2, 0, ctx)) < 0)

         return AVERROR(EINVAL);

     if ((ret =

@@ -792,14 +812,14 @@ static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)

     dtext->var_values[VAR_T] = inpicref->pts == AV_NOPTS_VALUE ?

         NAN : inpicref->pts * av_q2d(inlink->time_base);

     dtext->var_values[VAR_X] =

-        av_expr_eval(dtext->x_pexpr, dtext->var_values, NULL);

+        av_expr_eval(dtext->x_pexpr, dtext->var_values, &dtext->prng);

     dtext->var_values[VAR_Y] =

-        av_expr_eval(dtext->y_pexpr, dtext->var_values, NULL);

+        av_expr_eval(dtext->y_pexpr, dtext->var_values, &dtext->prng);

     dtext->var_values[VAR_X] =

-        av_expr_eval(dtext->x_pexpr, dtext->var_values, NULL);

+        av_expr_eval(dtext->x_pexpr, dtext->var_values, &dtext->prng);

     dtext->draw = fail ? 0 :

-        av_expr_eval(dtext->d_pexpr, dtext->var_values, NULL);

+        av_expr_eval(dtext->d_pexpr, dtext->var_values, &dtext->prng);

     normalize_double(&dtext->x, dtext->var_values[VAR_X]);

     normalize_double(&dtext->y, dtext->var_values[VAR_Y]);