Record B-fraction index from frame header and two fields from entry point structure

into VC-1 context.

Patch by Gwenole Beauchesne
(gbeauchesne <whirlpool> splitted <dash> desktop <dit> com)
Thread [PATCH][VC-1] Record extra syntax elements for VA API support

Originally committed as revision 16859 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vc1.c

@@ -1075,11 +1075,11 @@ static int decode_sequence_header_adv(VC1Context *v, GetBitContext *gb)
 static int decode_entry_point(AVCodecContext *avctx, GetBitContext *gb)
 {
     VC1Context *v = avctx->priv_data;
-    int i, blink, clentry;
+    int i;
 
     av_log(avctx, AV_LOG_DEBUG, "Entry point: %08X\n", show_bits_long(gb, 32));
-    blink = get_bits1(gb); // broken link
+    v->broken_link = get_bits1(gb);
-    clentry = get_bits1(gb); // closed entry
+    v->closed_entry = get_bits1(gb);
     v->panscanflag = get_bits1(gb);
     v->refdist_flag = get_bits1(gb);
     v->s.loop_filter = get_bits1(gb);
@@ -1115,7 +1115,7 @@ static int decode_entry_point(AVCodecContext *avctx, GetBitContext *gb)
         "BrokenLink=%i, ClosedEntry=%i, PanscanFlag=%i\n"
         "RefDist=%i, Postproc=%i, FastUVMC=%i, ExtMV=%i\n"
         "DQuant=%i, VSTransform=%i, Overlap=%i, Qmode=%i\n",
-        blink, clentry, v->panscanflag, v->refdist_flag, v->s.loop_filter,
+        v->broken_link, v->closed_entry, v->panscanflag, v->refdist_flag, v->s.loop_filter,
         v->fastuvmc, v->extended_mv, v->dquant, v->vstransform, v->overlap, v->quantizer_mode);
 
     return 0;
@@ -1139,8 +1139,8 @@ static int vc1_parse_frame_header(VC1Context *v, GetBitContext* gb)
 
     v->bi_type = 0;
     if(v->s.pict_type == FF_B_TYPE) {
-        v->bfraction = get_vlc2(gb, ff_vc1_bfraction_vlc.table, VC1_BFRACTION_VLC_BITS, 1);
+        v->bfraction_lut_index = get_vlc2(gb, ff_vc1_bfraction_vlc.table, VC1_BFRACTION_VLC_BITS, 1);
-        v->bfraction = ff_vc1_bfraction_lut[v->bfraction];
+        v->bfraction = ff_vc1_bfraction_lut[v->bfraction_lut_index];
         if(v->bfraction == 0) {
             v->s.pict_type = FF_BI_TYPE;
         }
@@ -1381,8 +1381,8 @@ static int vc1_parse_frame_header_adv(VC1Context *v, GetBitContext* gb)
         v->uvsamp = get_bits1(gb);
     if(v->finterpflag) v->interpfrm = get_bits1(gb);
     if(v->s.pict_type == FF_B_TYPE) {
-        v->bfraction = get_vlc2(gb, ff_vc1_bfraction_vlc.table, VC1_BFRACTION_VLC_BITS, 1);
+        v->bfraction_lut_index = get_vlc2(gb, ff_vc1_bfraction_vlc.table, VC1_BFRACTION_VLC_BITS, 1);
-        v->bfraction = ff_vc1_bfraction_lut[v->bfraction];
+        v->bfraction = ff_vc1_bfraction_lut[v->bfraction_lut_index];
         if(v->bfraction == 0) {
             v->s.pict_type = FF_BI_TYPE; /* XXX: should not happen here */
         }

libavcodec/vc1.h

@@ -307,6 +307,9 @@ typedef struct VC1Context{
     int x8_type;
 
     uint32_t *cbp_base, *cbp;
+    uint8_t bfraction_lut_index;///< Index for BFRACTION value (see Table 40, reproduced into ff_vc1_bfraction_lut[])
+    uint8_t broken_link;        ///< Broken link flag (BROKEN_LINK syntax element)
+    uint8_t closed_entry;       ///< Closed entry point flag (CLOSED_ENTRY syntax element)
 } VC1Context;
 
 #endif /* AVCODEC_VC1_H */