diff --git a/libavcodec/mpeg12enc.c b/libavcodec/mpeg12enc.c
index 96130eaa0f..5fc5e36b27 100644
--- a/libavcodec/mpeg12enc.c
+++ b/libavcodec/mpeg12enc.c
@@ -658,7 +658,7 @@ next_coef:
 }
 
 static av_always_inline void mpeg1_encode_mb_internal(MpegEncContext *s,
-                                                      int16_t block[6][64],
+                                                      int16_t block[8][64],
                                                       int motion_x, int motion_y,
                                                       int mb_block_count)
 {
@@ -935,7 +935,7 @@ static av_always_inline void mpeg1_encode_mb_internal(MpegEncContext *s,
     }
 }
 
-void ff_mpeg1_encode_mb(MpegEncContext *s, int16_t block[6][64],
+void ff_mpeg1_encode_mb(MpegEncContext *s, int16_t block[8][64],
                         int motion_x, int motion_y)
 {
     if (s->chroma_format == CHROMA_420)
diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
index 35ea5b1110..d9f3f0ec1d 100644
--- a/libavcodec/mpegvideo.h
+++ b/libavcodec/mpegvideo.h
@@ -837,7 +837,7 @@ extern const uint8_t * const ff_mpeg2_dc_scale_table[4];
 
 void ff_mpeg1_encode_picture_header(MpegEncContext *s, int picture_number);
 void ff_mpeg1_encode_mb(MpegEncContext *s,
-                        int16_t block[6][64],
+                        int16_t block[8][64],
                         int motion_x, int motion_y);
 void ff_mpeg1_encode_init(MpegEncContext *s);
 void ff_mpeg1_encode_slice_header(MpegEncContext *s);