diff --git a/libavcodec/aarch64/mpegaudiodsp_init.c b/libavcodec/aarch64/mpegaudiodsp_init.c
index e50e8da4e0..5d966af5f4 100644
--- a/libavcodec/aarch64/mpegaudiodsp_init.c
+++ b/libavcodec/aarch64/mpegaudiodsp_init.c
@@ -16,6 +16,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <stddef.h>
 #include <stdint.h>
 
 #include "libavutil/attributes.h"