diff --git a/libavformat/output-example.c b/libavformat/output-example.c
index ac7db48284..fb1d3a7819 100644
--- a/libavformat/output-example.c
+++ b/libavformat/output-example.c
@@ -27,10 +27,6 @@
 #include <string.h>
 #include <math.h>
 
-#ifndef M_PI
-#define M_PI 3.14159265358979323846
-#endif
-
 #include "libavformat/avformat.h"
 #include "libswscale/swscale.h"