avcodec/vdpau_mpeg4: fix order of quant matrix coefficients

The matrix coefficients are stored permutated for the IDCT,
rather then in plain raster order, and need to be un-permutated
for the hardware.

libavcodec/vdpau_mpeg4.c

@@ -74,8 +74,9 @@ static int vdpau_mpeg4_start_frame(AVCodecContext *avctx,
     info->alternate_vertical_scan_flag      = s->alternate_scan;
     info->top_field_first                   = s->top_field_first;
     for (i = 0; i < 64; ++i) {
-        info->intra_quantizer_matrix[i]     = s->intra_matrix[i];
-        info->non_intra_quantizer_matrix[i] = s->inter_matrix[i];
+        int n = s->idsp.idct_permutation[i];
+        info->intra_quantizer_matrix[i]     = s->intra_matrix[n];
+        info->non_intra_quantizer_matrix[i] = s->inter_matrix[n];
     }
 
     ff_vdpau_common_start_frame(pic_ctx, buffer, size);