diff --git a/libavcodec/x86/idctdsp.h b/libavcodec/x86/idctdsp.h
index e2e296ac81..0d0bdb5f57 100644
--- a/libavcodec/x86/idctdsp.h
+++ b/libavcodec/x86/idctdsp.h
@@ -21,7 +21,6 @@
 
 #include <stddef.h>
 #include <stdint.h>
-#include <stddef.h>
 
 void ff_add_pixels_clamped_mmx(const int16_t *block, uint8_t *pixels,
                                ptrdiff_t line_size);