diff --git a/libavfilter/avf_showcqt.c b/libavfilter/avf_showcqt.c
index 33c482bd42..c019dc2564 100644
--- a/libavfilter/avf_showcqt.c
+++ b/libavfilter/avf_showcqt.c
@@ -1187,6 +1187,7 @@ static int plot_cqt(AVFilterContext *ctx, AVFrame **frameout)
             UPDATE_TIME(s->sono_time);
         }
         out->pts = s->next_pts;
+        out->duration = PTS_STEP;
         s->next_pts += PTS_STEP;
     }
     s->sono_count = (s->sono_count + 1) % s->count;