merge 2 if()

this safes 1-2 cpu cycles

Originally committed as revision 9855 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpeg12.c

@@ -338,23 +338,20 @@ static int mpeg_decode_mb(MpegEncContext *s,
         if (mb_type & MB_TYPE_ZERO_MV){
             assert(mb_type & MB_TYPE_CBP);
 
-            /* compute dct type */
-            if (s->picture_structure == PICT_FRAME && //FIXME add a interlaced_dct coded var?
-                !s->frame_pred_frame_dct) {
-                s->interlaced_dct = get_bits1(&s->gb);
-            }
-
-            if (IS_QUANT(mb_type))
-                s->qscale = get_qscale(s);
-
             s->mv_dir = MV_DIR_FORWARD;
-            if(s->picture_structure == PICT_FRAME)
+            if(s->picture_structure == PICT_FRAME){
+                if(!s->frame_pred_frame_dct)
+                    s->interlaced_dct = get_bits1(&s->gb);
                 s->mv_type = MV_TYPE_16X16;
-            else{
+            }else{
                 s->mv_type = MV_TYPE_FIELD;
                 mb_type |= MB_TYPE_INTERLACED;
                 s->field_select[0][0]= s->picture_structure - 1;
             }
+
+            if (IS_QUANT(mb_type))
+                s->qscale = get_qscale(s);
+
             s->last_mv[0][0][0] = 0;
             s->last_mv[0][0][1] = 0;
             s->last_mv[0][1][0] = 0;