avfilter/avf_avectorscope: fix initialization for prev_y in polar mode

1 files changed, 1 insertions, 1 deletions

diff --git a/libavfilter/avf_avectorscope.c b/libavfilter/avf_avectorscope.c
index 0db30d370f..3063283efb 100644
--- a/libavfilter/avf_avectorscope.c
+++ b/libavfilter/avf_avectorscope.c
@@ -220,7 +220,7 @@ static int config_output(AVFilterLink *outlink)
     outlink->frame_rate = s->frame_rate;
 
     s->prev_x = s->hw = s->w / 2;
-    s->prev_y = s->hh = s->h / 2;
+    s->prev_y = s->hh = s->mode == POLAR ? s->h - 1 : s->h / 2;
 
     return 0;
 }