diff --git a/libavformat/apngenc.c b/libavformat/apngenc.c
index dcf6b906e1..9b2c634b95 100644
--- a/libavformat/apngenc.c
+++ b/libavformat/apngenc.c
@@ -173,7 +173,7 @@ static void flush_packet(AVFormatContext *format_context, AVPacket *packet)
                                "Frame rate is too high or specified too precisely. Unable to copy losslessly.\n");
                         apng->framerate_warned = 1;
                     }
-                } else if (apng->last_delay.den > 0) {
+                } else if (apng->last_delay.num > 0) {
                     delay = apng->last_delay;
                 } else {
                     delay = apng->prev_delay;