diff --git a/libavfilter/f_select.c b/libavfilter/f_select.c
index 47e36f0014..9b330a0673 100644
--- a/libavfilter/f_select.c
+++ b/libavfilter/f_select.c
@@ -233,6 +233,7 @@ static int config_input(AVFilterLink *inlink)
 
     select->var_values[VAR_TB] = av_q2d(inlink->time_base);
 
+    select->var_values[VAR_PREV_SELECTED_N]   = NAN;
     select->var_values[VAR_PREV_PTS]          = NAN;
     select->var_values[VAR_PREV_SELECTED_PTS] = NAN;
     select->var_values[VAR_PREV_SELECTED_T]   = NAN;