diff --git a/libavcodec/mpeg4videodec.h b/libavcodec/mpeg4videodec.h
index c0e6ec6592..4a26d18987 100644
--- a/libavcodec/mpeg4videodec.h
+++ b/libavcodec/mpeg4videodec.h
@@ -29,6 +29,7 @@
 #include "mpegvideo.h"
 #include "mpeg4videodsp.h"
 
+#include "libavutil/mem_internal.h"
 
 typedef struct Mpeg4DecContext {
     MpegEncContext m;
@@ -83,7 +84,7 @@ typedef struct Mpeg4DecContext {
 
     Mpeg4VideoDSPContext mdsp;
 
-    int32_t block32[12][64];
+    DECLARE_ALIGNED(8, int32_t, block32)[12][64];
     // 0 = DCT, 1 = DPCM top to bottom scan, -1 = DPCM bottom to top scan
     int dpcm_direction;
     int16_t dpcm_macroblock[3][256];