@@ -43,6 +43,8 @@ typedef struct {

     double start_x;

     double start_y;

     double start_scale;

+    double end_scale;

+    double end_pts;

     double bailout;

     enum Outer outer;

 } MBContext;

@@ -57,8 +59,10 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)

     mb->maxiter=256;

     mb->start_x=0;

-    mb->start_y=0;

+    mb->start_y=1;

     mb->start_scale=3.0;

+    mb->end_scale=0.3;

+    mb->end_pts=200;

     mb->bailout=100;

     mb->outer= NORMALIZED_ITERATION_COUNT;

     if (args)

@@ -69,6 +73,7 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)

         return AVERROR(EINVAL);

     }

     mb->start_scale /=mb->h;

+    mb->end_scale /=mb->h;

     if (av_parse_video_rate(&frame_rate_q, frame_rate) < 0 ||

         frame_rate_q.den <= 0 || frame_rate_q.num <= 0) {

@@ -119,10 +124,12 @@ static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize,

     MBContext *mb = ctx->priv;

     int x,y,i;

+    double scale= mb->start_scale*pow(mb->end_scale/mb->start_scale, pts/mb->end_pts);

+

     for(y=0; y<mb->h; y++){

         for(x=0; x<mb->w; x++){

-            const double cr=mb->start_x+mb->start_scale*(x-mb->w/2);

-            const double ci=mb->start_y+mb->start_scale*(y-mb->h/2);

+            const double cr=mb->start_x+scale*(x-mb->w/2);

+            const double ci=mb->start_y+scale*(y-mb->h/2);

             double zr=cr;

             double zi=ci;

             uint32_t c=0;