VC-1 postproc field is 2 bits wide while decoder read only single bit.

Spotted by Stephen Warren.

Originally committed as revision 16725 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vc1.c

@@ -1407,7 +1407,7 @@ static int vc1_parse_frame_header_adv(VC1Context *v, GetBitContext* gb)
     if (v->quantizer_mode == QUANT_FRAME_EXPLICIT)
         v->pquantizer = get_bits1(gb);
     if(v->postprocflag)
-        v->postproc = get_bits1(gb);
+        v->postproc = get_bits(gb, 2);
 
     if(v->s.pict_type == FF_I_TYPE || v->s.pict_type == FF_P_TYPE) v->use_ic = 0;