diff --git a/libavfilter/vf_estdif.c b/libavfilter/vf_estdif.c
index 192837ab0f..863d453775 100644
--- a/libavfilter/vf_estdif.c
+++ b/libavfilter/vf_estdif.c
@@ -498,7 +498,7 @@ static int config_input(AVFilterLink *inlink)
         return 0;
     }
 
-    if ((s->deint && !in->interlaced_frame) || ctx->is_disabled) {
+    if ((s->deint && !s->prev->interlaced_frame) || ctx->is_disabled) {
         s->prev->pts *= 2;
         ret = ff_filter_frame(ctx->outputs[0], s->prev);
         s->prev = in;
diff --git a/libavfilter/vf_nnedi.c b/libavfilter/vf_nnedi.c
index 95b736afc1..dd476aeb04 100644
--- a/libavfilter/vf_nnedi.c
+++ b/libavfilter/vf_nnedi.c
@@ -694,7 +694,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
         return 0;
     }
 
-    if ((s->deint && !in->interlaced_frame) || ctx->is_disabled) {
+    if ((s->deint && !s->prev->interlaced_frame) || ctx->is_disabled) {
         s->prev->pts *= 2;
         ret = ff_filter_frame(ctx->outputs[0], s->prev);
         s->prev = in;