@@ -269,6 +269,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)

 static int config_props(AVFilterLink *inlink)

 {

     VignetteContext *s = inlink->dst->priv;

+    AVRational sar = inlink->sample_aspect_ratio;

     s->desc = av_pix_fmt_desc_get(inlink->format);

     s->var_values[VAR_W]  = inlink->w;

@@ -277,12 +278,14 @@ static int config_props(AVFilterLink *inlink)

     s->var_values[VAR_R]  = inlink->frame_rate.num == 0 || inlink->frame_rate.den == 0 ?

         NAN : av_q2d(inlink->frame_rate);

-    if (inlink->sample_aspect_ratio.num > inlink->sample_aspect_ratio.den) {

-        s->xscale = av_q2d(inlink->sample_aspect_ratio);

+    if (!sar.num || !sar.den)

+        sar.num = sar.den = 1;

+    if (sar.num > sar.den) {

+        s->xscale = av_q2d(sar);

         s->yscale = 1;

         s->dmax = hypot(inlink->w / 2., s->yscale * inlink->h / 2.);

     } else {

-        s->yscale = av_q2d(inlink->sample_aspect_ratio);

+        s->yscale = av_q2d(sar);

         s->xscale = 1;

         s->dmax = hypot(s->xscale * inlink->w / 2., inlink->h / 2.);

     }