vc1dec: fix handling of max_coded dimensions

Fixes Ticket1502
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/vc1.c

@@ -418,7 +418,6 @@ int ff_vc1_decode_sequence_header(AVCodecContext *avctx, VC1Context *v, GetBitCo
 
 static int decode_sequence_header_adv(VC1Context *v, GetBitContext *gb)
 {
-    int w, h;
     v->res_rtm_flag = 1;
     v->level = get_bits(gb, 3);
     if (v->level >= 5) {
@@ -437,9 +436,8 @@ static int decode_sequence_header_adv(VC1Context *v, GetBitContext *gb)
     v->bitrtq_postproc       = get_bits(gb, 5); //common
     v->postprocflag          = get_bits1(gb);   //common
 
-    w = (get_bits(gb, 12) + 1) << 1;
-    h = (get_bits(gb, 12) + 1) << 1;
-    avcodec_set_dimensions(v->s.avctx, w, h);
+    v->max_coded_width       = (get_bits(gb, 12) + 1) << 1;
+    v->max_coded_height      = (get_bits(gb, 12) + 1) << 1;
     v->broadcast             = get_bits1(gb);
     v->interlace             = get_bits1(gb);
     v->tfcntrflag            = get_bits1(gb);
@@ -528,6 +526,7 @@ static int decode_sequence_header_adv(VC1Context *v, GetBitContext *gb)
 int ff_vc1_decode_entry_point(AVCodecContext *avctx, VC1Context *v, GetBitContext *gb)
 {
     int i;
+    int w,h;
 
     av_log(avctx, AV_LOG_DEBUG, "Entry point: %08X\n", show_bits_long(gb, 32));
     v->broken_link    = get_bits1(gb);
@@ -551,10 +550,13 @@ int ff_vc1_decode_entry_point(AVCodecContext *avctx, VC1Context *v, GetBitContex
     }
 
     if(get_bits1(gb)){
-        int w = (get_bits(gb, 12)+1)<<1;
-        int h = (get_bits(gb, 12)+1)<<1;
-        avcodec_set_dimensions(avctx, w, h);
+        w = (get_bits(gb, 12)+1)<<1;
+        h = (get_bits(gb, 12)+1)<<1;
+    } else {
+        w = v->max_coded_width;
+        h = v->max_coded_height;
     }
+    avcodec_set_dimensions(avctx, w, h);
     if (v->extended_mv)
         v->extended_dmv = get_bits1(gb);
     if ((v->range_mapy_flag = get_bits1(gb))) {

libavcodec/vc1.h

@@ -225,6 +225,7 @@ typedef struct VC1Context{
     int profile;          ///< 2bits, Profile
     int frmrtq_postproc;  ///< 3bits,
     int bitrtq_postproc;  ///< 5bits, quantized framerate-based postprocessing strength
+    int max_coded_width, max_coded_height;
     int fastuvmc;         ///< Rounding of qpel vector to hpel ? (not in Simple)
     int extended_mv;      ///< Ext MV in P/B (not in Simple)
     int dquant;           ///< How qscale varies with MBs, 2bits (not in Simple)