diff --git a/fftools/ffprobe.c b/fftools/ffprobe.c
index 82dfe4f58ae8fd295eecc4f2ce7f210ce55b4a82..8b2a18b6b12b0e58f5d9ad10f1edd3e1833b0ec8 100644
--- a/fftools/ffprobe.c
+++ b/fftools/ffprobe.c
@@ -2521,7 +2521,7 @@ static int show_stream(WriterContext *w, AVFormatContext *fmt_ctx, int stream_id
 #endif
         print_int("has_b_frames", par->video_delay);
         sar = av_guess_sample_aspect_ratio(fmt_ctx, stream, NULL);
-        if (sar.den) {
+        if (sar.num) {
             print_q("sample_aspect_ratio", sar, ':');
             av_reduce(&dar.num, &dar.den,
                       par->width  * sar.num,