diff --git a/libavutil/internal.h b/libavutil/internal.h
index d77170a257..67f9fe6d9e 100644
--- a/libavutil/internal.h
+++ b/libavutil/internal.h
@@ -108,6 +108,7 @@
 
 #ifdef USE_FASTMEMCPY
 #    include "libvo/fastmemcpy.h"
+#    define memcpy(a,b,c) fast_memcpy(a,b,c)
 #endif
 
 // Use rip-relative addressing if compiling PIC code on x86-64.