diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index ad2dfbd0fb..1ece371bdb 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -2787,14 +2787,12 @@ static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
                     last = v;
                     j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
                     s->intra_matrix[j]        = last;
-                    s->chroma_intra_matrix[j] = last;
                 }
 
                 /* replicate last value */
                 for (; i < 64; i++) {
                     int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
                     s->intra_matrix[j]        = last;
-                    s->chroma_intra_matrix[j] = last;
                 }
             }
 
@@ -2814,14 +2812,12 @@ static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
                     last = v;
                     j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
                     s->inter_matrix[j]        = v;
-                    s->chroma_inter_matrix[j] = v;
                 }
 
                 /* replicate last value */
                 for (; i < 64; i++) {
                     int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
                     s->inter_matrix[j]        = last;
-                    s->chroma_inter_matrix[j] = last;
                 }
             }