diff --git a/av1/encoder/pass2_strategy.c b/av1/encoder/pass2_strategy.c
index 6adc1fb..dae4847 100644
--- a/av1/encoder/pass2_strategy.c
+++ b/av1/encoder/pass2_strategy.c
@@ -2549,7 +2549,8 @@
   }
 
   // Keyframe and section processing.
-  if (rc->frames_to_key == 0 || (frame_flags & FRAMEFLAGS_KEY)) {
+  if (rc->frames_to_key <= 0 || (frame_flags & FRAMEFLAGS_KEY)) {
+    assert(rc->frames_to_key >= -1);
     FIRSTPASS_STATS this_frame_copy;
     this_frame_copy = this_frame;
     frame_params->frame_type = KEY_FRAME;