fixed block permutation in encoder (not optimal - should move it in forward DCT code)

Originally committed as revision 51 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpegvideo.c

@@ -1068,6 +1068,10 @@ static int dct_quantize_mmx(MpegEncContext *s,
     const int *qmat;
 
     av_fdct (block);
+    
+    /* we need this permutation so that we correct the IDCT
+       permutation. will be moved into DCT code */
+    block_permute(block);
 
     if (s->mb_intra) {
         if (n < 4)