/*

  * MPEG-1/2 decoder

  * Copyright (c) 2000, 2001 Fabrice Bellard

  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>

  *

  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either

  * version 2.1 of the License, or (at your option) any later version.

  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.

  *

  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */

 /**

  * @file

  * MPEG-1/2 decoder

  */

 #define UNCHECKED_BITSTREAM_READER 1
 

 //#define DEBUG

 #include "internal.h"

 #include "avcodec.h"
 #include "dsputil.h"
 #include "mpegvideo.h"

 #include "libavutil/avassert.h"

 #include "libavutil/timecode.h"

 #include "mpeg12.h"

 #include "mpeg12data.h"

 #include "mpeg12decdata.h"

 #include "bytestream.h"

 #include "vdpau_internal.h"

 #include "xvmc_internal.h"

 #include "thread.h"

 #define MV_VLC_BITS 9
 #define MBINCR_VLC_BITS 9
 #define MB_PAT_VLC_BITS 9
 #define MB_PTYPE_VLC_BITS 6
 #define MB_BTYPE_VLC_BITS 6
 

 static VLC mv_vlc;
 

 /* as H.263, but only 17 codes */

 static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
 {

     int code, sign, val, shift;

     code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);

     if (code == 0) {
         return pred;
     }

     if (code < 0) {
         return 0xffff;
     }
 

     sign  = get_bits1(&s->gb);

     shift = fcode - 1;

     val   = code;

     if (shift) {

         val  = (val - 1) << shift;

         val |= get_bits(&s->gb, shift);

         val++;
     }

     if (sign)
         val = -val;
     val += pred;

     /* modulo decoding */

     return sign_extend(val, 5 + shift);

 }
 

 static inline int mpeg1_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n)

 {
     int level, dc, diff, i, j, run;

     int component;

     RLTable *rl = &ff_rl_mpeg1;

     uint8_t * const scantable    = s->intra_scantable.permutated;
     const uint16_t *quant_matrix = s->intra_matrix;
     const int qscale             = s->qscale;

     /* DC coefficient */

     component = (n <= 3 ? 0 : n - 4 + 1);

     diff = decode_dc(&s->gb, component);

     if (diff >= 0xffff)
         return -1;

     dc  = s->last_dc[component];

     dc += diff;
     s->last_dc[component] = dc;

     block[0] = dc * quant_matrix[0];

     av_dlog(s->avctx, "dc=%d diff=%d\n", dc, diff);

     i = 0;
     {

         OPEN_READER(re, &s->gb);

         /* now quantify & encode AC coefficients */

         for (;;) {

             UPDATE_CACHE(re, &s->gb);

             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

             if (level == 127) {

                 break;

             } else if (level != 0) {

                 i += run;
                 j = scantable[i];

                 level = (level * qscale * quant_matrix[j]) >> 4;
                 level = (level - 1) | 1;

                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
                 LAST_SKIP_BITS(re, &s->gb, 1);
             } else {
                 /* escape */

                 run = SHOW_UBITS(re, &s->gb, 6) + 1; LAST_SKIP_BITS(re, &s->gb, 6);

                 UPDATE_CACHE(re, &s->gb);
                 level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
                 if (level == -128) {
                     level = SHOW_UBITS(re, &s->gb, 8) - 256; LAST_SKIP_BITS(re, &s->gb, 8);
                 } else if (level == 0) {
                     level = SHOW_UBITS(re, &s->gb, 8)      ; LAST_SKIP_BITS(re, &s->gb, 8);
                 }
                 i += run;
                 j = scantable[i];

                 if (level < 0) {
                     level = -level;
                     level = (level * qscale * quant_matrix[j]) >> 4;
                     level = (level - 1) | 1;
                     level = -level;
                 } else {
                     level = (level * qscale * quant_matrix[j]) >> 4;
                     level = (level - 1) | 1;

                 }
             }

             if (i > 63) {

                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);

                 return -1;
             }
 
             block[j] = level;
         }
         CLOSE_READER(re, &s->gb);
     }
     s->block_last_index[n] = i;
    return 0;
 }
 

 int ff_mpeg1_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n)

 {
     return mpeg1_decode_block_intra(s, block, n);
 }
 

 static inline int mpeg1_decode_block_inter(MpegEncContext *s, DCTELEM *block, int n)

 {
     int level, i, j, run;

     RLTable *rl = &ff_rl_mpeg1;

     uint8_t * const scantable    = s->intra_scantable.permutated;
     const uint16_t *quant_matrix = s->inter_matrix;
     const int qscale             = s->qscale;

 
     {

         OPEN_READER(re, &s->gb);

         i = -1;

         // special case for first coefficient, no need to add second VLC table

         UPDATE_CACHE(re, &s->gb);

         if (((int32_t)GET_CACHE(re, &s->gb)) < 0) {

             level = (3 * qscale * quant_matrix[0]) >> 5;
             level = (level - 1) | 1;
             if (GET_CACHE(re, &s->gb) & 0x40000000)
                 level = -level;

             block[0] = level;

             i++;

             SKIP_BITS(re, &s->gb, 2);

             if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)

                 goto end;

         }

         /* now quantify & encode AC coefficients */

         for (;;) {

             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

             if (level != 0) {

                 i += run;
                 j = scantable[i];

                 level = ((level * 2 + 1) * qscale * quant_matrix[j]) >> 5;
                 level = (level - 1) | 1;

                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);

                 SKIP_BITS(re, &s->gb, 1);

             } else {
                 /* escape */

                 run = SHOW_UBITS(re, &s->gb, 6) + 1; LAST_SKIP_BITS(re, &s->gb, 6);

                 UPDATE_CACHE(re, &s->gb);
                 level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
                 if (level == -128) {

                     level = SHOW_UBITS(re, &s->gb, 8) - 256; SKIP_BITS(re, &s->gb, 8);

                 } else if (level == 0) {

                     level = SHOW_UBITS(re, &s->gb, 8)      ; SKIP_BITS(re, &s->gb, 8);

                 }
                 i += run;
                 j = scantable[i];

                 if (level < 0) {
                     level = -level;
                     level = ((level * 2 + 1) * qscale * quant_matrix[j]) >> 5;
                     level = (level - 1) | 1;
                     level = -level;
                 } else {
                     level = ((level * 2 + 1) * qscale * quant_matrix[j]) >> 5;
                     level = (level - 1) | 1;

                 }

             }

             if (i > 63) {

                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);

                 return -1;
             }
 
             block[j] = level;

             if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)

                 break;
             UPDATE_CACHE(re, &s->gb);

         }

 end:
         LAST_SKIP_BITS(re, &s->gb, 2);

         CLOSE_READER(re, &s->gb);

     }

     s->block_last_index[n] = i;

     return 0;
 }
 

 /**
  * Note: this function can read out of range and crash for corrupt streams.
  * Changing this would eat up any speed benefits it has.
  * Do not use "fast" flag if you need the code to be robust.
  */

 static inline int mpeg1_fast_decode_block_inter(MpegEncContext *s, DCTELEM *block, int n)
 {
     int level, i, j, run;

     RLTable *rl = &ff_rl_mpeg1;

     uint8_t * const scantable = s->intra_scantable.permutated;
     const int qscale          = s->qscale;

 
     {
         OPEN_READER(re, &s->gb);
         i = -1;

         // special case for first coefficient, no need to add second VLC table

         UPDATE_CACHE(re, &s->gb);

         if (((int32_t)GET_CACHE(re, &s->gb)) < 0) {

             level = (3 * qscale) >> 1;
             level = (level - 1) | 1;
             if (GET_CACHE(re, &s->gb) & 0x40000000)
                 level = -level;

             block[0] = level;
             i++;

             SKIP_BITS(re, &s->gb, 2);

             if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)

                 goto end;

         }
 

         /* now quantify & encode AC coefficients */

         for (;;) {

             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

             if (level != 0) {

                 i += run;
                 j = scantable[i];

                 level = ((level * 2 + 1) * qscale) >> 1;
                 level = (level - 1) | 1;

                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);

                 SKIP_BITS(re, &s->gb, 1);

             } else {
                 /* escape */
                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
                 UPDATE_CACHE(re, &s->gb);
                 level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
                 if (level == -128) {

                     level = SHOW_UBITS(re, &s->gb, 8) - 256; SKIP_BITS(re, &s->gb, 8);

                 } else if (level == 0) {

                     level = SHOW_UBITS(re, &s->gb, 8)      ; SKIP_BITS(re, &s->gb, 8);

                 }
                 i += run;
                 j = scantable[i];

                 if (level < 0) {
                     level = -level;
                     level = ((level * 2 + 1) * qscale) >> 1;
                     level = (level - 1) | 1;
                     level = -level;
                 } else {
                     level = ((level * 2 + 1) * qscale) >> 1;
                     level = (level - 1) | 1;

                 }
             }
 
             block[j] = level;

             if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)

                 break;
             UPDATE_CACHE(re, &s->gb);

         }

 end:
         LAST_SKIP_BITS(re, &s->gb, 2);

         CLOSE_READER(re, &s->gb);
     }
     s->block_last_index[n] = i;
     return 0;
 }
 
 

 static inline int mpeg2_decode_block_non_intra(MpegEncContext *s, DCTELEM *block, int n)

 {
     int level, i, j, run;

     RLTable *rl = &ff_rl_mpeg1;

     uint8_t * const scantable = s->intra_scantable.permutated;

     const uint16_t *quant_matrix;

     const int qscale = s->qscale;

     int mismatch;
 
     mismatch = 1;
 
     {

         OPEN_READER(re, &s->gb);

         i = -1;

         if (n < 4)

             quant_matrix = s->inter_matrix;

         else

             quant_matrix = s->chroma_inter_matrix;

         // special case for first coefficient, no need to add second VLC table

         UPDATE_CACHE(re, &s->gb);

         if (((int32_t)GET_CACHE(re, &s->gb)) < 0) {

             level= (3 * qscale * quant_matrix[0]) >> 5;
             if (GET_CACHE(re, &s->gb) & 0x40000000)
                 level = -level;
             block[0]  = level;

             mismatch ^= level;
             i++;

             SKIP_BITS(re, &s->gb, 2);

             if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)

                 goto end;

         }
 

         /* now quantify & encode AC coefficients */

         for (;;) {

             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

             if (level != 0) {

                 i += run;
                 j = scantable[i];

                 level = ((level * 2 + 1) * qscale * quant_matrix[j]) >> 5;

                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);

                 SKIP_BITS(re, &s->gb, 1);

             } else {
                 /* escape */

                 run = SHOW_UBITS(re, &s->gb, 6) + 1; LAST_SKIP_BITS(re, &s->gb, 6);

                 UPDATE_CACHE(re, &s->gb);
                 level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
 
                 i += run;
                 j = scantable[i];

                 if (level < 0) {
                     level = ((-level * 2 + 1) * qscale * quant_matrix[j]) >> 5;
                     level = -level;
                 } else {
                     level = ((level * 2 + 1) * qscale * quant_matrix[j]) >> 5;

                 }
             }

             if (i > 63) {

                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);

                 return -1;
             }

             mismatch ^= level;

             block[j]  = level;
             if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)

                 break;
             UPDATE_CACHE(re, &s->gb);

         }

 end:
         LAST_SKIP_BITS(re, &s->gb, 2);

         CLOSE_READER(re, &s->gb);

     }
     block[63] ^= (mismatch & 1);

     s->block_last_index[n] = i;
     return 0;
 }
 

 /**
  * Note: this function can read out of range and crash for corrupt streams.
  * Changing this would eat up any speed benefits it has.
  * Do not use "fast" flag if you need the code to be robust.
  */

 static inline int mpeg2_fast_decode_block_non_intra(MpegEncContext *s,

                                                     DCTELEM *block, int n)

 {
     int level, i, j, run;

     RLTable *rl = &ff_rl_mpeg1;

     uint8_t * const scantable = s->intra_scantable.permutated;
     const int qscale          = s->qscale;

     OPEN_READER(re, &s->gb);
     i = -1;
 

     // special case for first coefficient, no need to add second VLC table

     UPDATE_CACHE(re, &s->gb);

     if (((int32_t)GET_CACHE(re, &s->gb)) < 0) {

         level = (3 * qscale) >> 1;
         if (GET_CACHE(re, &s->gb) & 0x40000000)
             level = -level;

         block[0] = level;
         i++;

         SKIP_BITS(re, &s->gb, 2);

         if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)

             goto end;

     }
 

     /* now quantify & encode AC coefficients */

     for (;;) {

         GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

         if (level != 0) {

             i += run;

             j  = scantable[i];
             level = ((level * 2 + 1) * qscale) >> 1;

             level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);

             SKIP_BITS(re, &s->gb, 1);

         } else {
             /* escape */

             run = SHOW_UBITS(re, &s->gb, 6) + 1; LAST_SKIP_BITS(re, &s->gb, 6);

             UPDATE_CACHE(re, &s->gb);
             level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
 
             i += run;

             j  = scantable[i];
             if (level < 0) {
                 level = ((-level * 2 + 1) * qscale) >> 1;
                 level = -level;
             } else {
                 level = ((level * 2 + 1) * qscale) >> 1;

             }
         }

         block[j] = level;

         if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)

             break;
         UPDATE_CACHE(re, &s->gb);

     }

 end:

     LAST_SKIP_BITS(re, &s->gb, 2);

     CLOSE_READER(re, &s->gb);
     s->block_last_index[n] = i;
     return 0;
 }
 
 

 static inline int mpeg2_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n)

 {
     int level, dc, diff, i, j, run;

     int component;

     RLTable *rl;

     uint8_t * const scantable = s->intra_scantable.permutated;

     const uint16_t *quant_matrix;

     const int qscale = s->qscale;

     int mismatch;
 

     /* DC coefficient */

     if (n < 4) {

         quant_matrix = s->intra_matrix;

         component = 0;

     } else {

         quant_matrix = s->chroma_intra_matrix;

         component = (n & 1) + 1;

     }

     diff = decode_dc(&s->gb, component);

     if (diff >= 0xffff)
         return -1;

     dc  = s->last_dc[component];

     dc += diff;
     s->last_dc[component] = dc;
     block[0] = dc << (3 - s->intra_dc_precision);

     av_dlog(s->avctx, "dc=%d\n", block[0]);

     mismatch = block[0] ^ 1;

     i = 0;

     if (s->intra_vlc_format)

         rl = &ff_rl_mpeg2;

     else

         rl = &ff_rl_mpeg1;

     {

         OPEN_READER(re, &s->gb);

         /* now quantify & encode AC coefficients */

         for (;;) {

             UPDATE_CACHE(re, &s->gb);

             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

             if (level == 127) {

                 break;

             } else if (level != 0) {

                 i += run;

                 j  = scantable[i];
                 level = (level * qscale * quant_matrix[j]) >> 4;

                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
                 LAST_SKIP_BITS(re, &s->gb, 1);
             } else {
                 /* escape */

                 run = SHOW_UBITS(re, &s->gb, 6) + 1; LAST_SKIP_BITS(re, &s->gb, 6);

                 UPDATE_CACHE(re, &s->gb);
                 level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
                 i += run;

                 j  = scantable[i];
                 if (level < 0) {
                     level = (-level * qscale * quant_matrix[j]) >> 4;
                     level = -level;
                 } else {
                     level = (level * qscale * quant_matrix[j]) >> 4;

                 }
             }

             if (i > 63) {

                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);

                 return -1;
             }

             mismatch ^= level;
             block[j]  = level;

         }

         CLOSE_READER(re, &s->gb);

     }

     block[63] ^= mismatch & 1;

     s->block_last_index[n] = i;
     return 0;
 }
 

 /**
  * Note: this function can read out of range and crash for corrupt streams.
  * Changing this would eat up any speed benefits it has.
  * Do not use "fast" flag if you need the code to be robust.
  */

 static inline int mpeg2_fast_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n)

 {
     int level, dc, diff, j, run;
     int component;
     RLTable *rl;

     uint8_t * scantable = s->intra_scantable.permutated;

     const uint16_t *quant_matrix;

     const int qscale = s->qscale;

     /* DC coefficient */

     if (n < 4) {

         quant_matrix = s->intra_matrix;

         component = 0;

     } else {

         quant_matrix = s->chroma_intra_matrix;

         component = (n & 1) + 1;

     }
     diff = decode_dc(&s->gb, component);
     if (diff >= 0xffff)
         return -1;
     dc = s->last_dc[component];
     dc += diff;
     s->last_dc[component] = dc;
     block[0] = dc << (3 - s->intra_dc_precision);
     if (s->intra_vlc_format)

         rl = &ff_rl_mpeg2;

     else

         rl = &ff_rl_mpeg1;

 
     {

         OPEN_READER(re, &s->gb);

         /* now quantify & encode AC coefficients */

         for (;;) {

             UPDATE_CACHE(re, &s->gb);
             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

             if (level == 127) {

                 break;

             } else if (level != 0) {

                 scantable += run;
                 j = *scantable;

                 level = (level * qscale * quant_matrix[j]) >> 4;

                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
                 LAST_SKIP_BITS(re, &s->gb, 1);
             } else {
                 /* escape */

                 run = SHOW_UBITS(re, &s->gb, 6) + 1; LAST_SKIP_BITS(re, &s->gb, 6);

                 UPDATE_CACHE(re, &s->gb);
                 level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
                 scantable += run;
                 j = *scantable;

                 if (level < 0) {
                     level = (-level * qscale * quant_matrix[j]) >> 4;
                     level = -level;
                 } else {
                     level = (level * qscale * quant_matrix[j]) >> 4;

                 }
             }

             block[j] = level;
         }
         CLOSE_READER(re, &s->gb);
     }

     s->block_last_index[n] = scantable - s->intra_scantable.permutated;
     return 0;
 }
 

 uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3];
 
 #define INIT_2D_VLC_RL(rl, static_size)\
 {\
     static RL_VLC_ELEM rl_vlc_table[static_size];\
     INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\
                     &rl.table_vlc[0][1], 4, 2,\
                     &rl.table_vlc[0][0], 4, 2, static_size);\
 \
     rl.rl_vlc[0] = rl_vlc_table;\
     init_2d_vlc_rl(&rl);\
 }
 
 static void init_2d_vlc_rl(RLTable *rl)
 {
     int i;
 
     for (i = 0; i < rl->vlc.table_size; i++) {
         int code = rl->vlc.table[i][0];
         int len  = rl->vlc.table[i][1];
         int level, run;
 
         if (len == 0) { // illegal code
             run   = 65;
             level = MAX_LEVEL;
         } else if (len<0) { //more bits needed
             run   = 0;
             level = code;
         } else {
             if (code == rl->n) { //esc
                 run   = 65;
                 level = 0;
             } else if (code == rl->n+1) { //eob
                 run   = 0;
                 level = 127;
             } else {
                 run   = rl->table_run  [code] + 1;
                 level = rl->table_level[code];
             }
         }
         rl->rl_vlc[0][i].len   = len;
         rl->rl_vlc[0][i].level = level;
         rl->rl_vlc[0][i].run   = run;
     }
 }
 
 void ff_mpeg12_common_init(MpegEncContext *s)
 {
 
     s->y_dc_scale_table =
     s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
 
 }
 
 void ff_mpeg1_clean_buffers(MpegEncContext *s)
 {
     s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
     s->last_dc[1] = s->last_dc[0];
     s->last_dc[2] = s->last_dc[0];
     memset(s->last_mv, 0, sizeof(s->last_mv));
 }
 
 
 /******************************************/
 /* decoding */
 
 VLC ff_dc_lum_vlc;
 VLC ff_dc_chroma_vlc;
 
 static VLC mbincr_vlc;
 static VLC mb_ptype_vlc;
 static VLC mb_btype_vlc;
 static VLC mb_pat_vlc;
 
 av_cold void ff_mpeg12_init_vlcs(void)
 {
     static int done = 0;
 
     if (!done) {
         done = 1;
 
         INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
                         ff_mpeg12_vlc_dc_lum_bits, 1, 1,
                         ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
         INIT_VLC_STATIC(&ff_dc_chroma_vlc,  DC_VLC_BITS, 12,
                         ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
                         ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
         INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 17,
                         &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
                         &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 518);
         INIT_VLC_STATIC(&mbincr_vlc, MBINCR_VLC_BITS, 36,
                         &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
                         &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
         INIT_VLC_STATIC(&mb_pat_vlc, MB_PAT_VLC_BITS, 64,
                         &ff_mpeg12_mbPatTable[0][1], 2, 1,
                         &ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
 
         INIT_VLC_STATIC(&mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
                         &table_mb_ptype[0][1], 2, 1,
                         &table_mb_ptype[0][0], 2, 1, 64);
         INIT_VLC_STATIC(&mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
                         &table_mb_btype[0][1], 2, 1,
                         &table_mb_btype[0][0], 2, 1, 64);

         ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]);
         ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]);

 
         INIT_2D_VLC_RL(ff_rl_mpeg1, 680);
         INIT_2D_VLC_RL(ff_rl_mpeg2, 674);
     }
 }
 
 static inline int get_dmv(MpegEncContext *s)
 {
     if (get_bits1(&s->gb))
         return 1 - (get_bits1(&s->gb) << 1);
     else
         return 0;
 }
 
 static inline int get_qscale(MpegEncContext *s)
 {
     int qscale = get_bits(&s->gb, 5);
     if (s->q_scale_type) {
         return non_linear_qscale[qscale];
     } else {
         return qscale << 1;
     }
 }
 
 static void exchange_uv(MpegEncContext *s)
 {
     DCTELEM (*tmp)[64];
 
     tmp           = s->pblocks[4];
     s->pblocks[4] = s->pblocks[5];
     s->pblocks[5] = tmp;
 }
 
 /* motion type (for MPEG-2) */
 #define MT_FIELD 1
 #define MT_FRAME 2
 #define MT_16X8  2
 #define MT_DMV   3
 

 static int mpeg_decode_mb(MpegEncContext *s, DCTELEM block[12][64])

 {
     int i, j, k, cbp, val, mb_type, motion_type;
     const int mb_block_count = 4 + (1 << s->chroma_format);
 
     av_dlog(s->avctx, "decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y);
 

     av_assert2(s->mb_skipped == 0);

 
     if (s->mb_skip_run-- != 0) {
         if (s->pict_type == AV_PICTURE_TYPE_P) {
             s->mb_skipped = 1;
             s->current_picture.f.mb_type[s->mb_x + s->mb_y * s->mb_stride] = MB_TYPE_SKIP | MB_TYPE_L0 | MB_TYPE_16x16;
         } else {
             int mb_type;
 
             if (s->mb_x)
                 mb_type = s->current_picture.f.mb_type[s->mb_x + s->mb_y * s->mb_stride - 1];
             else
                 mb_type = s->current_picture.f.mb_type[s->mb_width + (s->mb_y - 1) * s->mb_stride - 1]; // FIXME not sure if this is allowed in MPEG at all
             if (IS_INTRA(mb_type))
                 return -1;
             s->current_picture.f.mb_type[s->mb_x + s->mb_y*s->mb_stride] =
                 mb_type | MB_TYPE_SKIP;

 //            av_assert2(s->current_picture.f.mb_type[s->mb_x + s->mb_y * s->mb_stride - 1] & (MB_TYPE_16x16 | MB_TYPE_16x8));

 
             if ((s->mv[0][0][0] | s->mv[0][0][1] | s->mv[1][0][0] | s->mv[1][0][1]) == 0)
                 s->mb_skipped = 1;
         }
 
         return 0;
     }
 
     switch (s->pict_type) {
     default:
     case AV_PICTURE_TYPE_I:
         if (get_bits1(&s->gb) == 0) {
             if (get_bits1(&s->gb) == 0) {
                 av_log(s->avctx, AV_LOG_ERROR, "invalid mb type in I Frame at %d %d\n", s->mb_x, s->mb_y);
                 return -1;
             }
             mb_type = MB_TYPE_QUANT | MB_TYPE_INTRA;
         } else {
             mb_type = MB_TYPE_INTRA;
         }
         break;
     case AV_PICTURE_TYPE_P:
         mb_type = get_vlc2(&s->gb, mb_ptype_vlc.table, MB_PTYPE_VLC_BITS, 1);
         if (mb_type < 0) {
             av_log(s->avctx, AV_LOG_ERROR, "invalid mb type in P Frame at %d %d\n", s->mb_x, s->mb_y);
             return -1;
         }
         mb_type = ptype2mb_type[mb_type];
         break;
     case AV_PICTURE_TYPE_B:
         mb_type = get_vlc2(&s->gb, mb_btype_vlc.table, MB_BTYPE_VLC_BITS, 1);
         if (mb_type < 0) {
             av_log(s->avctx, AV_LOG_ERROR, "invalid mb type in B Frame at %d %d\n", s->mb_x, s->mb_y);
             return -1;
         }
         mb_type = btype2mb_type[mb_type];
         break;
     }
     av_dlog(s->avctx, "mb_type=%x\n", mb_type);
 //    motion_type = 0; /* avoid warning */
     if (IS_INTRA(mb_type)) {
         s->dsp.clear_blocks(s->block[0]);
 
         if (!s->chroma_y_shift) {
             s->dsp.clear_blocks(s->block[6]);
         }
 
         /* compute DCT type */
         if (s->picture_structure == PICT_FRAME && // FIXME add an 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);
 
         if (s->concealment_motion_vectors) {
             /* just parse them */
             if (s->picture_structure != PICT_FRAME)
                 skip_bits1(&s->gb); /* field select */
 
             s->mv[0][0][0]= s->last_mv[0][0][0]= s->last_mv[0][1][0] =
                 mpeg_decode_motion(s, s->mpeg_f_code[0][0], s->last_mv[0][0][0]);
             s->mv[0][0][1]= s->last_mv[0][0][1]= s->last_mv[0][1][1] =
                 mpeg_decode_motion(s, s->mpeg_f_code[0][1], s->last_mv[0][0][1]);
 
             skip_bits1(&s->gb); /* marker */
         } else
             memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */
         s->mb_intra = 1;
         // if 1, we memcpy blocks in xvmcvideo
         if (CONFIG_MPEG_XVMC_DECODER && s->avctx->xvmc_acceleration > 1) {
             ff_xvmc_pack_pblocks(s, -1); // inter are always full blocks
             if (s->swap_uv) {
                 exchange_uv(s);
             }
         }
 

         if (s->codec_id == AV_CODEC_ID_MPEG2VIDEO) {

             if (s->flags2 & CODEC_FLAG2_FAST) {
                 for (i = 0; i < 6; i++) {
                     mpeg2_fast_decode_block_intra(s, *s->pblocks[i], i);
                 }
             } else {
                 for (i = 0; i < mb_block_count; i++) {
                     if (mpeg2_decode_block_intra(s, *s->pblocks[i], i) < 0)
                         return -1;
                 }
             }
         } else {
             for (i = 0; i < 6; i++) {
                 if (mpeg1_decode_block_intra(s, *s->pblocks[i], i) < 0)
                     return -1;
             }
         }
     } else {
         if (mb_type & MB_TYPE_ZERO_MV) {

             av_assert2(mb_type & MB_TYPE_CBP);

 
             s->mv_dir = MV_DIR_FORWARD;
             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 {
                 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;
             s->last_mv[0][1][1] = 0;
             s->mv[0][0][0] = 0;
             s->mv[0][0][1] = 0;
         } else {

             av_assert2(mb_type & MB_TYPE_L0L1);

             // FIXME decide if MBs in field pictures are MB_TYPE_INTERLACED
             /* get additional motion vector type */
             if (s->frame_pred_frame_dct)
                 motion_type = MT_FRAME;
             else {
                 motion_type = get_bits(&s->gb, 2);
                 if (s->picture_structure == PICT_FRAME && HAS_CBP(mb_type))
                     s->interlaced_dct = get_bits1(&s->gb);
             }
 
             if (IS_QUANT(mb_type))
                 s->qscale = get_qscale(s);
 
             /* motion vectors */
             s->mv_dir = (mb_type >> 13) & 3;
             av_dlog(s->avctx, "motion_type=%d\n", motion_type);
             switch (motion_type) {
             case MT_FRAME: /* or MT_16X8 */
                 if (s->picture_structure == PICT_FRAME) {
                     mb_type |= MB_TYPE_16x16;
                     s->mv_type = MV_TYPE_16X16;
                     for (i = 0; i < 2; i++) {
                         if (USES_LIST(mb_type, i)) {
                             /* MT_FRAME */
                             s->mv[i][0][0]= s->last_mv[i][0][0]= s->last_mv[i][1][0] =
                                 mpeg_decode_motion(s, s->mpeg_f_code[i][0], s->last_mv[i][0][0]);
                             s->mv[i][0][1]= s->last_mv[i][0][1]= s->last_mv[i][1][1] =
                                 mpeg_decode_motion(s, s->mpeg_f_code[i][1], s->last_mv[i][0][1]);
                             /* full_pel: only for MPEG-1 */

                             if (s->full_pel[i]) {

                                 s->mv[i][0][0] <<= 1;
                                 s->mv[i][0][1] <<= 1;
                             }
                         }
                     }
                 } else {
                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
                     s->mv_type = MV_TYPE_16X8;
                     for (i = 0; i < 2; i++) {
                         if (USES_LIST(mb_type, i)) {
                             /* MT_16X8 */
                             for (j = 0; j < 2; j++) {
                                 s->field_select[i][j] = get_bits1(&s->gb);
                                 for (k = 0; k < 2; k++) {
                                     val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
                                                              s->last_mv[i][j][k]);
                                     s->last_mv[i][j][k] = val;
                                     s->mv[i][j][k]      = val;
                                 }
                             }
                         }
                     }
                 }
                 break;
             case MT_FIELD:
                 s->mv_type = MV_TYPE_FIELD;
                 if (s->picture_structure == PICT_FRAME) {
                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
                     for (i = 0; i < 2; i++) {
                         if (USES_LIST(mb_type, i)) {
                             for (j = 0; j < 2; j++) {
                                 s->field_select[i][j] = get_bits1(&s->gb);
                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
                                                          s->last_mv[i][j][0]);
                                 s->last_mv[i][j][0] = val;
                                 s->mv[i][j][0]      = val;
                                 av_dlog(s->avctx, "fmx=%d\n", val);
                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
                                                          s->last_mv[i][j][1] >> 1);
                                 s->last_mv[i][j][1] = val << 1;
                                 s->mv[i][j][1]      = val;
                                 av_dlog(s->avctx, "fmy=%d\n", val);
                             }
                         }
                     }
                 } else {

                     av_assert0(!s->progressive_sequence);

                     mb_type |= MB_TYPE_16x16 | MB_TYPE_INTERLACED;
                     for (i = 0; i < 2; i++) {
                         if (USES_LIST(mb_type, i)) {
                             s->field_select[i][0] = get_bits1(&s->gb);
                             for (k = 0; k < 2; k++) {
                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
                                                          s->last_mv[i][0][k]);
                                 s->last_mv[i][0][k] = val;
                                 s->last_mv[i][1][k] = val;
                                 s->mv[i][0][k]      = val;
                             }
                         }
                     }
                 }
                 break;
             case MT_DMV:

                 if(s->progressive_sequence){
                     av_log(s->avctx, AV_LOG_ERROR, "MT_DMV in progressive_sequence\n");
                     return -1;
                 }

                 s->mv_type = MV_TYPE_DMV;
                 for (i = 0; i < 2; i++) {
                     if (USES_LIST(mb_type, i)) {
                         int dmx, dmy, mx, my, m;
                         const int my_shift = s->picture_structure == PICT_FRAME;
 
                         mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
                                                 s->last_mv[i][0][0]);
                         s->last_mv[i][0][0] = mx;
                         s->last_mv[i][1][0] = mx;
                         dmx = get_dmv(s);
                         my  = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
                                                  s->last_mv[i][0][1] >> my_shift);
                         dmy = get_dmv(s);
 
 
                         s->last_mv[i][0][1] = my << my_shift;
                         s->last_mv[i][1][1] = my << my_shift;
 
                         s->mv[i][0][0] = mx;
                         s->mv[i][0][1] = my;
                         s->mv[i][1][0] = mx; // not used
                         s->mv[i][1][1] = my; // not used
 
                         if (s->picture_structure == PICT_FRAME) {
                             mb_type |= MB_TYPE_16x16 | MB_TYPE_INTERLACED;
 
                             // m = 1 + 2 * s->top_field_first;
                             m = s->top_field_first ? 1 : 3;
 
                             /* top -> top pred */
                             s->mv[i][2][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
                             s->mv[i][2][1] = ((my * m + (my > 0)) >> 1) + dmy - 1;
                             m = 4 - m;
                             s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
                             s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1;
                         } else {
                             mb_type |= MB_TYPE_16x16;
 
                             s->mv[i][2][0] = ((mx + (mx > 0)) >> 1) + dmx;
                             s->mv[i][2][1] = ((my + (my > 0)) >> 1) + dmy;
                             if (s->picture_structure == PICT_TOP_FIELD)
                                 s->mv[i][2][1]--;
                             else
                                 s->mv[i][2][1]++;
                         }
                     }
                 }
                 break;
             default:
                 av_log(s->avctx, AV_LOG_ERROR, "00 motion_type at %d %d\n", s->mb_x, s->mb_y);
                 return -1;
             }
         }
 
         s->mb_intra = 0;
         if (HAS_CBP(mb_type)) {
             s->dsp.clear_blocks(s->block[0]);
 
             cbp = get_vlc2(&s->gb, mb_pat_vlc.table, MB_PAT_VLC_BITS, 1);
             if (mb_block_count > 6) {
                  cbp <<= mb_block_count - 6;
                  cbp  |= get_bits(&s->gb, mb_block_count - 6);
                  s->dsp.clear_blocks(s->block[6]);
             }
             if (cbp <= 0) {
                 av_log(s->avctx, AV_LOG_ERROR, "invalid cbp at %d %d\n", s->mb_x, s->mb_y);
                 return -1;
             }
 
             //if 1, we memcpy blocks in xvmcvideo
             if (CONFIG_MPEG_XVMC_DECODER && s->avctx->xvmc_acceleration > 1) {
                 ff_xvmc_pack_pblocks(s, cbp);
                 if (s->swap_uv) {
                     exchange_uv(s);
                 }
             }
 

             if (s->codec_id == AV_CODEC_ID_MPEG2VIDEO) {

                 if (s->flags2 & CODEC_FLAG2_FAST) {
                     for (i = 0; i < 6; i++) {
                         if (cbp & 32) {
                             mpeg2_fast_decode_block_non_intra(s, *s->pblocks[i], i);
                         } else {
                             s->block_last_index[i] = -1;
                         }
                         cbp += cbp;
                     }
                 } else {
                     cbp <<= 12-mb_block_count;
 
                     for (i = 0; i < mb_block_count; i++) {
                         if (cbp & (1 << 11)) {
                             if (mpeg2_decode_block_non_intra(s, *s->pblocks[i], i) < 0)
                                 return -1;
                         } else {
                             s->block_last_index[i] = -1;
                         }
                         cbp += cbp;
                     }
                 }
             } else {
                 if (s->flags2 & CODEC_FLAG2_FAST) {
                     for (i = 0; i < 6; i++) {
                         if (cbp & 32) {
                             mpeg1_fast_decode_block_inter(s, *s->pblocks[i], i);
                         } else {
                             s->block_last_index[i] = -1;
                         }
                         cbp += cbp;
                     }
                 } else {
                     for (i = 0; i < 6; i++) {
                         if (cbp & 32) {
                             if (mpeg1_decode_block_inter(s, *s->pblocks[i], i) < 0)
                                 return -1;
                         } else {
                             s->block_last_index[i] = -1;
                         }
                         cbp += cbp;
                     }
                 }
             }
         } else {
             for (i = 0; i < 12; i++)
                 s->block_last_index[i] = -1;
         }
     }
 
     s->current_picture.f.mb_type[s->mb_x + s->mb_y * s->mb_stride] = mb_type;
 
     return 0;
 }
 

 static av_cold int mpeg_decode_init(AVCodecContext *avctx)

 {
     Mpeg1Context *s = avctx->priv_data;

     MpegEncContext *s2 = &s->mpeg_enc_ctx;

     int i;

     /* we need some permutation to store matrices,
      * until MPV_common_init() sets the real permutation. */

     for (i = 0; i < 64; i++)

        s2->dsp.idct_permutation[i]=i;
 

     ff_MPV_decode_defaults(s2);

     s->mpeg_enc_ctx.avctx  = avctx;
     s->mpeg_enc_ctx.flags  = avctx->flags;
     s->mpeg_enc_ctx.flags2 = avctx->flags2;

     ff_mpeg12_common_init(&s->mpeg_enc_ctx);

     ff_mpeg12_init_vlcs();

     s->mpeg_enc_ctx_allocated      = 0;

     s->mpeg_enc_ctx.picture_number = 0;

     s->repeat_field                = 0;
     s->mpeg_enc_ctx.codec_id       = avctx->codec->id;
     avctx->color_range = AVCOL_RANGE_MPEG;

     if (avctx->codec->id == AV_CODEC_ID_MPEG1VIDEO)

         avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
     else
         avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;

     return 0;
 }
 

 static int mpeg_decode_update_thread_context(AVCodecContext *avctx, const AVCodecContext *avctx_from)
 {
     Mpeg1Context *ctx = avctx->priv_data, *ctx_from = avctx_from->priv_data;
     MpegEncContext *s = &ctx->mpeg_enc_ctx, *s1 = &ctx_from->mpeg_enc_ctx;
     int err;
 

     if (avctx == avctx_from || !ctx_from->mpeg_enc_ctx_allocated || !s1->context_initialized)

         return 0;
 
     err = ff_mpeg_update_thread_context(avctx, avctx_from);

     if (err) return err;

     if (!ctx->mpeg_enc_ctx_allocated)

         memcpy(s + 1, s1 + 1, sizeof(Mpeg1Context) - sizeof(MpegEncContext));
 

     if (!(s->pict_type == AV_PICTURE_TYPE_B || s->low_delay))

         s->picture_number++;
 
     return 0;
 }
 

 static void quant_matrix_rebuild(uint16_t *matrix, const uint8_t *old_perm,

                                  const uint8_t *new_perm)
 {

     uint16_t temp_matrix[64];
     int i;

     memcpy(temp_matrix, matrix, 64 * sizeof(uint16_t));

     for (i = 0; i < 64; i++) {

         matrix[new_perm[i]] = temp_matrix[old_perm[i]];

     }

 }
 

 static const enum PixelFormat mpeg1_hwaccel_pixfmt_list_420[] = {

 #if CONFIG_MPEG_XVMC_DECODER

     PIX_FMT_XVMC_MPEG2_IDCT,
     PIX_FMT_XVMC_MPEG2_MC,

 #endif
 #if CONFIG_MPEG1_VDPAU_HWACCEL

     PIX_FMT_VDPAU_MPEG1,

 #endif

     PIX_FMT_YUV420P,
     PIX_FMT_NONE
 };
 
 static const enum PixelFormat mpeg2_hwaccel_pixfmt_list_420[] = {

 #if CONFIG_MPEG_XVMC_DECODER

     PIX_FMT_XVMC_MPEG2_IDCT,
     PIX_FMT_XVMC_MPEG2_MC,

 #endif
 #if CONFIG_MPEG2_VDPAU_HWACCEL

     PIX_FMT_VDPAU_MPEG2,

 #endif
 #if CONFIG_MPEG2_DXVA2_HWACCEL

     PIX_FMT_DXVA2_VLD,

 #endif
 #if CONFIG_MPEG2_VAAPI_HWACCEL

     PIX_FMT_VAAPI_VLD,

 #endif

     PIX_FMT_YUV420P,
     PIX_FMT_NONE
 };
 
 static inline int uses_vdpau(AVCodecContext *avctx) {
     return avctx->pix_fmt == PIX_FMT_VDPAU_MPEG1 || avctx->pix_fmt == PIX_FMT_VDPAU_MPEG2;
 }
 

 static enum PixelFormat mpeg_get_pixelformat(AVCodecContext *avctx)
 {

     Mpeg1Context *s1 = avctx->priv_data;
     MpegEncContext *s = &s1->mpeg_enc_ctx;
 

     if(s->chroma_format < 2) {
         enum PixelFormat res;
         res = avctx->get_format(avctx,

                                 avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO ?

                                 mpeg1_hwaccel_pixfmt_list_420 :
                                 mpeg2_hwaccel_pixfmt_list_420);
         if (res != PIX_FMT_XVMC_MPEG2_IDCT && res != PIX_FMT_XVMC_MPEG2_MC) {
             avctx->xvmc_acceleration = 0;
         } else if (!avctx->xvmc_acceleration) {
             avctx->xvmc_acceleration = 2;
         }
         return res;
     } else if(s->chroma_format == 2)
         return PIX_FMT_YUV422P;
     else
         return PIX_FMT_YUV444P;

 }
 

 /* Call this function when we know all parameters.
  * It may be called in different places for MPEG-1 and MPEG-2. */

 static int mpeg_decode_postinit(AVCodecContext *avctx)
 {

     Mpeg1Context *s1 = avctx->priv_data;
     MpegEncContext *s = &s1->mpeg_enc_ctx;
     uint8_t old_permutation[64];

     if ((s1->mpeg_enc_ctx_allocated == 0) ||
         avctx->coded_width  != s->width   ||
         avctx->coded_height != s->height  ||
         s1->save_width           != s->width                ||
         s1->save_height          != s->height               ||
         s1->save_aspect_info     != s->aspect_ratio_info    ||

         s1->save_progressive_seq != s->progressive_sequence ||

         0)
     {

         if (s1->mpeg_enc_ctx_allocated) {

             ParseContext pc = s->parse_context;
             s->parse_context.buffer = 0;

             ff_MPV_common_end(s);

             s->parse_context = pc;

         }
 

         if ((s->width == 0) || (s->height == 0))

             return -2;

         avcodec_set_dimensions(avctx, s->width, s->height);

         avctx->bit_rate          = s->bit_rate;
         s1->save_aspect_info     = s->aspect_ratio_info;
         s1->save_width           = s->width;
         s1->save_height          = s->height;

         s1->save_progressive_seq = s->progressive_sequence;

         /* low_delay may be forced, in this case we will have B-frames
          * that behave like P-frames. */

         avctx->has_b_frames = !s->low_delay;

         if (avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO) {

             //MPEG-1 fps

             avctx->time_base.den = avpriv_frame_rate_tab[s->frame_rate_index].num;
             avctx->time_base.num = avpriv_frame_rate_tab[s->frame_rate_index].den;

             //MPEG-1 aspect

             avctx->sample_aspect_ratio = av_d2q(1.0/ff_mpeg1_aspect[s->aspect_ratio_info], 255);

             avctx->ticks_per_frame=1;

         } else {//MPEG-2

         //MPEG-2 fps

             av_reduce(&s->avctx->time_base.den,
                       &s->avctx->time_base.num,

                       avpriv_frame_rate_tab[s->frame_rate_index].num * s1->frame_rate_ext.num*2,
                       avpriv_frame_rate_tab[s->frame_rate_index].den * s1->frame_rate_ext.den,

                       1 << 30);
             avctx->ticks_per_frame = 2;
             //MPEG-2 aspect
             if (s->aspect_ratio_info > 1) {

                 AVRational dar =

                     av_mul_q(av_div_q(ff_mpeg2_aspect[s->aspect_ratio_info],
                                       (AVRational) {s1->pan_scan.width, s1->pan_scan.height}),
                              (AVRational) {s->width, s->height});

                 // we ignore the spec here and guess a bit as reality does not match the spec, see for example

                 // res_change_ffmpeg_aspect.ts and sequence-display-aspect.mpg

                 // issue1613, 621, 562

                 if ((s1->pan_scan.width == 0) || (s1->pan_scan.height == 0) ||
                    (av_cmp_q(dar, (AVRational) {4, 3}) && av_cmp_q(dar, (AVRational) {16, 9}))) {
                     s->avctx->sample_aspect_ratio =
                         av_div_q(ff_mpeg2_aspect[s->aspect_ratio_info],
                                  (AVRational) {s->width, s->height});
                 } else {
                     s->avctx->sample_aspect_ratio =
                         av_div_q(ff_mpeg2_aspect[s->aspect_ratio_info],
                                  (AVRational) {s1->pan_scan.width, s1->pan_scan.height});

 //issue1613 4/3 16/9 -> 16/9
 //res_change_ffmpeg_aspect.ts 4/3 225/44 ->4/3
 //widescreen-issue562.mpg 4/3 16/9 -> 16/9

 //                    s->avctx->sample_aspect_ratio = av_mul_q(s->avctx->sample_aspect_ratio, (AVRational) {s->width, s->height});
 //av_log(NULL, AV_LOG_ERROR, "A %d/%d\n", ff_mpeg2_aspect[s->aspect_ratio_info].num, ff_mpeg2_aspect[s->aspect_ratio_info].den);
 //av_log(NULL, AV_LOG_ERROR, "B %d/%d\n", s->avctx->sample_aspect_ratio.num, s->avctx->sample_aspect_ratio.den);

                 }

             } else {
                 s->avctx->sample_aspect_ratio =

                     ff_mpeg2_aspect[s->aspect_ratio_info];

             }

         } // MPEG-2

         avctx->pix_fmt = mpeg_get_pixelformat(avctx);

         avctx->hwaccel = ff_find_hwaccel(avctx->codec->id, avctx->pix_fmt);

         // until then pix_fmt may be changed right after codec init
         if (avctx->pix_fmt == PIX_FMT_XVMC_MPEG2_IDCT ||

             avctx->hwaccel )

             if (avctx->idct_algo == FF_IDCT_AUTO)

                 avctx->idct_algo = FF_IDCT_SIMPLE;
 

         /* Quantization matrices may need reordering
          * if DCT permutation is changed. */

         memcpy(old_permutation, s->dsp.idct_permutation, 64 * sizeof(uint8_t));

         if (ff_MPV_common_init(s) < 0)

             return -2;
 

         quant_matrix_rebuild(s->intra_matrix,        old_permutation, s->dsp.idct_permutation);
         quant_matrix_rebuild(s->inter_matrix,        old_permutation, s->dsp.idct_permutation);
         quant_matrix_rebuild(s->chroma_intra_matrix, old_permutation, s->dsp.idct_permutation);
         quant_matrix_rebuild(s->chroma_inter_matrix, old_permutation, s->dsp.idct_permutation);

 
         s1->mpeg_enc_ctx_allocated = 1;
     }
     return 0;
 }
 

 static int mpeg1_decode_picture(AVCodecContext *avctx,

                                 const uint8_t *buf, int buf_size)

 {
     Mpeg1Context *s1 = avctx->priv_data;
     MpegEncContext *s = &s1->mpeg_enc_ctx;

     int ref, f_code, vbv_delay;

     init_get_bits(&s->gb, buf, buf_size*8);

 
     ref = get_bits(&s->gb, 10); /* temporal ref */
     s->pict_type = get_bits(&s->gb, 3);

     if (s->pict_type == 0 || s->pict_type > 3)

         return -1;

     vbv_delay = get_bits(&s->gb, 16);

     if (s->pict_type == AV_PICTURE_TYPE_P || s->pict_type == AV_PICTURE_TYPE_B) {

         s->full_pel[0] = get_bits1(&s->gb);

         f_code = get_bits(&s->gb, 3);

         if (f_code == 0 && (avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT)))

             return -1;

         f_code += !f_code;

         s->mpeg_f_code[0][0] = f_code;
         s->mpeg_f_code[0][1] = f_code;
     }

     if (s->pict_type == AV_PICTURE_TYPE_B) {

         s->full_pel[1] = get_bits1(&s->gb);

         f_code = get_bits(&s->gb, 3);

         if (f_code == 0 && (avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT)))

             return -1;

         f_code += !f_code;

         s->mpeg_f_code[1][0] = f_code;
         s->mpeg_f_code[1][1] = f_code;
     }

     s->current_picture.f.pict_type = s->pict_type;
     s->current_picture.f.key_frame = s->pict_type == AV_PICTURE_TYPE_I;

     if (avctx->debug & FF_DEBUG_PICT_INFO)

         av_log(avctx, AV_LOG_DEBUG, "vbv_delay %d, ref %d type:%d\n", vbv_delay, ref, s->pict_type);

     s->y_dc_scale = 8;
     s->c_dc_scale = 8;
     return 0;
 }
 

 static void mpeg_decode_sequence_extension(Mpeg1Context *s1)

 {

     MpegEncContext *s= &s1->mpeg_enc_ctx;

     int horiz_size_ext, vert_size_ext;

     int bit_rate_ext;

     skip_bits(&s->gb, 1); /* profile and level esc*/

     s->avctx->profile       = get_bits(&s->gb, 3);
     s->avctx->level         = get_bits(&s->gb, 4);

     s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */

     s->chroma_format        = get_bits(&s->gb, 2); /* chroma_format 1=420, 2=422, 3=444 */
     horiz_size_ext          = get_bits(&s->gb, 2);
     vert_size_ext           = get_bits(&s->gb, 2);
     s->width  |= (horiz_size_ext << 12);
     s->height |= (vert_size_ext  << 12);

     bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */

     s->bit_rate += (bit_rate_ext << 18) * 400;

     skip_bits1(&s->gb); /* marker */

     s->avctx->rc_buffer_size += get_bits(&s->gb, 8) * 1024 * 16 << 10;

     s->low_delay = get_bits1(&s->gb);

     if (s->flags & CODEC_FLAG_LOW_DELAY)
         s->low_delay = 1;

     s1->frame_rate_ext.num = get_bits(&s->gb, 2) + 1;
     s1->frame_rate_ext.den = get_bits(&s->gb, 5) + 1;

     av_dlog(s->avctx, "sequence extension\n");

     s->codec_id      = s->avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO;

     if (s->avctx->debug & FF_DEBUG_PICT_INFO)

         av_log(s->avctx, AV_LOG_DEBUG, "profile: %d, level: %d vbv buffer: %d, bitrate:%d\n",

                s->avctx->profile, s->avctx->level, s->avctx->rc_buffer_size, s->bit_rate);

 }
 

 static void mpeg_decode_sequence_display_extension(Mpeg1Context *s1)
 {

     MpegEncContext *s = &s1->mpeg_enc_ctx;

     int color_description, w, h;
 
     skip_bits(&s->gb, 3); /* video format */

     color_description = get_bits1(&s->gb);
     if (color_description) {
         s->avctx->color_primaries = get_bits(&s->gb, 8);
         s->avctx->color_trc       = get_bits(&s->gb, 8);
         s->avctx->colorspace      = get_bits(&s->gb, 8);

     }

     w = get_bits(&s->gb, 14);

     skip_bits(&s->gb, 1); //marker

     h = get_bits(&s->gb, 14);

     // remaining 3 bits are zero padding

     s1->pan_scan.width  = 16 * w;
     s1->pan_scan.height = 16 * h;

     if (s->avctx->debug & FF_DEBUG_PICT_INFO)

         av_log(s->avctx, AV_LOG_DEBUG, "sde w:%d, h:%d\n", w, h);

 }
 
 static void mpeg_decode_picture_display_extension(Mpeg1Context *s1)
 {

     MpegEncContext *s = &s1->mpeg_enc_ctx;
     int i, nofco;

 
     nofco = 1;

     if (s->progressive_sequence) {
         if (s->repeat_first_field) {

             nofco++;

             if (s->top_field_first)

                 nofco++;
         }

     } else {
         if (s->picture_structure == PICT_FRAME) {

             nofco++;

             if (s->repeat_first_field)

                 nofco++;
         }

     }

     for (i = 0; i < nofco; i++) {
         s1->pan_scan.position[i][0] = get_sbits(&s->gb, 16);
         skip_bits(&s->gb, 1); // marker
         s1->pan_scan.position[i][1] = get_sbits(&s->gb, 16);
         skip_bits(&s->gb, 1); // marker

     }

     if (s->avctx->debug & FF_DEBUG_PICT_INFO)

         av_log(s->avctx, AV_LOG_DEBUG, "pde (%d,%d) (%d,%d) (%d,%d)\n",

                s1->pan_scan.position[0][0], s1->pan_scan.position[0][1],
                s1->pan_scan.position[1][0], s1->pan_scan.position[1][1],
                s1->pan_scan.position[2][0], s1->pan_scan.position[2][1]);

 }
 

 static int load_matrix(MpegEncContext *s, uint16_t matrix0[64], uint16_t matrix1[64], int intra)
 {

     int i;
 

     for (i = 0; i < 64; i++) {
         int j = s->dsp.idct_permutation[ff_zigzag_direct[i]];

         int v = get_bits(&s->gb, 8);

         if (v == 0) {

             av_log(s->avctx, AV_LOG_ERROR, "matrix damaged\n");
             return -1;
         }

         if (intra && i == 0 && v != 8) {

             av_log(s->avctx, AV_LOG_DEBUG, "intra matrix specifies invalid DC quantizer %d, ignoring\n", v);

             v = 8; // needed by pink.mpg / issue1046

         }

         matrix0[j] = v;

         if (matrix1)

             matrix1[j] = v;
     }
     return 0;
 }
 

 static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)
 {

     av_dlog(s->avctx, "matrix extension\n");

     if (get_bits1(&s->gb)) load_matrix(s, s->chroma_intra_matrix, s->intra_matrix, 1);
     if (get_bits1(&s->gb)) load_matrix(s, s->chroma_inter_matrix, s->inter_matrix, 0);
     if (get_bits1(&s->gb)) load_matrix(s, s->chroma_intra_matrix, NULL           , 1);
     if (get_bits1(&s->gb)) load_matrix(s, s->chroma_inter_matrix, NULL           , 0);

 }
 

 static void mpeg_decode_picture_coding_extension(Mpeg1Context *s1)

 {

     MpegEncContext *s = &s1->mpeg_enc_ctx;

     s->full_pel[0] = s->full_pel[1] = 0;

     s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);
     s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);
     s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);
     s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);

     if (!s->pict_type && s1->mpeg_enc_ctx_allocated) {

         av_log(s->avctx, AV_LOG_ERROR, "Missing picture start code, guessing missing values\n");

         if (s->mpeg_f_code[1][0] == 15 && s->mpeg_f_code[1][1] == 15) {
             if (s->mpeg_f_code[0][0] == 15 && s->mpeg_f_code[0][1] == 15)
                 s->pict_type = AV_PICTURE_TYPE_I;

             else

                 s->pict_type = AV_PICTURE_TYPE_P;
         } else
             s->pict_type = AV_PICTURE_TYPE_B;

         s->current_picture.f.pict_type = s->pict_type;
         s->current_picture.f.key_frame = s->pict_type == AV_PICTURE_TYPE_I;

     }

     s->mpeg_f_code[0][0] += !s->mpeg_f_code[0][0];
     s->mpeg_f_code[0][1] += !s->mpeg_f_code[0][1];
     s->mpeg_f_code[1][0] += !s->mpeg_f_code[1][0];
     s->mpeg_f_code[1][1] += !s->mpeg_f_code[1][1];
 

     s->intra_dc_precision         = get_bits(&s->gb, 2);
     s->picture_structure          = get_bits(&s->gb, 2);
     s->top_field_first            = get_bits1(&s->gb);
     s->frame_pred_frame_dct       = get_bits1(&s->gb);

     s->concealment_motion_vectors = get_bits1(&s->gb);

     s->q_scale_type               = get_bits1(&s->gb);
     s->intra_vlc_format           = get_bits1(&s->gb);
     s->alternate_scan             = get_bits1(&s->gb);
     s->repeat_first_field         = get_bits1(&s->gb);
     s->chroma_420_type            = get_bits1(&s->gb);
     s->progressive_frame          = get_bits1(&s->gb);
 

     if (s->alternate_scan) {
         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable, ff_alternate_vertical_scan);
         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable, ff_alternate_vertical_scan);
     } else {
         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable, ff_zigzag_direct);
         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct);

     }

     /* composite display not parsed */

     av_dlog(s->avctx, "intra_dc_precision=%d\n", s->intra_dc_precision);
     av_dlog(s->avctx, "picture_structure=%d\n", s->picture_structure);
     av_dlog(s->avctx, "top field first=%d\n", s->top_field_first);
     av_dlog(s->avctx, "repeat first field=%d\n", s->repeat_first_field);
     av_dlog(s->avctx, "conceal=%d\n", s->concealment_motion_vectors);
     av_dlog(s->avctx, "intra_vlc_format=%d\n", s->intra_vlc_format);
     av_dlog(s->avctx, "alternate_scan=%d\n", s->alternate_scan);
     av_dlog(s->avctx, "frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);
     av_dlog(s->avctx, "progressive_frame=%d\n", s->progressive_frame);

 }
 

 static int mpeg_field_start(MpegEncContext *s, const uint8_t *buf, int buf_size)
 {
     AVCodecContext *avctx = s->avctx;

     Mpeg1Context *s1 = (Mpeg1Context*)s;

 
     /* start frame decoding */

     if (s->first_field || s->picture_structure == PICT_FRAME) {

         if (ff_MPV_frame_start(s, avctx) < 0)

             return -1;

 
         ff_er_frame_start(s);
 

         /* first check if we must repeat the frame */

         s->current_picture_ptr->f.repeat_pict = 0;

         if (s->repeat_first_field) {
             if (s->progressive_sequence) {
                 if (s->top_field_first)

                     s->current_picture_ptr->f.repeat_pict = 4;

                 else

                     s->current_picture_ptr->f.repeat_pict = 2;

             } else if (s->progressive_frame) {

                 s->current_picture_ptr->f.repeat_pict = 1;

             }

         }

         *s->current_picture_ptr->f.pan_scan = s1->pan_scan;

         if (HAVE_THREADS && (avctx->active_thread_type & FF_THREAD_FRAME))

             ff_thread_finish_setup(avctx);

     } else { // second field
         int i;

         if (!s->current_picture_ptr) {
             av_log(s->avctx, AV_LOG_ERROR, "first field missing\n");
             return -1;
         }

         if (s->avctx->hwaccel &&
             (s->avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD)) {
             if (s->avctx->hwaccel->end_frame(s->avctx) < 0)
                 av_log(avctx, AV_LOG_ERROR, "hardware accelerator failed to decode first field\n");
         }
 

         for (i = 0; i < 4; i++) {
             s->current_picture.f.data[i] = s->current_picture_ptr->f.data[i];
             if (s->picture_structure == PICT_BOTTOM_FIELD) {
                 s->current_picture.f.data[i] += s->current_picture_ptr->f.linesize[i];

             }

         }

     }

 
     if (avctx->hwaccel) {
         if (avctx->hwaccel->start_frame(avctx, buf, buf_size) < 0)
             return -1;
     }
 

 // MPV_frame_start will call this function too,
 // but we need to call it on every field

     if (CONFIG_MPEG_XVMC_DECODER && s->avctx->xvmc_acceleration)
         if (ff_xvmc_field_start(s, avctx) < 0)

             return -1;

     return 0;
 }
 
 #define DECODE_SLICE_ERROR -1

 #define DECODE_SLICE_OK     0

 
 /**

  * Decode a slice.
  * MpegEncContext.mb_y must be set to the MB row from the startcode.
  * @return DECODE_SLICE_ERROR if the slice is damaged,
  *         DECODE_SLICE_OK if this slice is OK

  */

 static int mpeg_decode_slice(MpegEncContext *s, int mb_y,

                              const uint8_t **buf, int buf_size)

 {

     AVCodecContext *avctx = s->avctx;

     const int lowres      = s->avctx->lowres;

     const int field_pic   = s->picture_structure != PICT_FRAME;

     s->resync_mb_x =
     s->resync_mb_y = -1;

     av_assert0(mb_y < s->mb_height);

     init_get_bits(&s->gb, *buf, buf_size * 8);

     if(s->codec_id != AV_CODEC_ID_MPEG1VIDEO && s->mb_height > 2800/16)

         skip_bits(&s->gb, 3);

     ff_mpeg1_clean_buffers(s);
     s->interlaced_dct = 0;
 

     s->qscale = get_qscale(s);

     if (s->qscale == 0) {

         av_log(s->avctx, AV_LOG_ERROR, "qscale == 0\n");

         return -1;

     }

     /* extra slice info */

     while (get_bits1(&s->gb) != 0) {
         skip_bits(&s->gb, 8);

     }

     s->mb_x = 0;

     if (mb_y == 0 && s->codec_tag == AV_RL32("SLIF")) {

         skip_bits1(&s->gb);

     } else {

         while (get_bits_left(&s->gb) > 0) {

             int code = get_vlc2(&s->gb, mbincr_vlc.table, MBINCR_VLC_BITS, 2);

             if (code < 0) {

                 av_log(s->avctx, AV_LOG_ERROR, "first mb_incr damaged\n");
                 return -1;
             }
             if (code >= 33) {
                 if (code == 33) {
                     s->mb_x += 33;
                 }
                 /* otherwise, stuffing, nothing to do */
             } else {
                 s->mb_x += code;
                 break;

             }
         }
     }

     if (s->mb_x >= (unsigned)s->mb_width) {

         av_log(s->avctx, AV_LOG_ERROR, "initial skip overflow\n");
         return -1;
     }

     if (avctx->hwaccel) {
         const uint8_t *buf_end, *buf_start = *buf - 4; /* include start_code */
         int start_code = -1;

         buf_end = avpriv_mpv_find_start_code(buf_start + 2, *buf + buf_size, &start_code);

         if (buf_end < *buf + buf_size)
             buf_end -= 4;
         s->mb_y = mb_y;
         if (avctx->hwaccel->decode_slice(avctx, buf_start, buf_end - buf_start) < 0)
             return DECODE_SLICE_ERROR;
         *buf = buf_end;
         return DECODE_SLICE_OK;
     }
 

     s->resync_mb_x = s->mb_x;
     s->resync_mb_y = s->mb_y = mb_y;
     s->mb_skip_run = 0;

     ff_init_block_index(s);

     if (s->mb_y == 0 && s->mb_x == 0 && (s->first_field || s->picture_structure == PICT_FRAME)) {
         if (s->avctx->debug & FF_DEBUG_PICT_INFO) {

              av_log(s->avctx, AV_LOG_DEBUG, "qp:%d fc:%2d%2d%2d%2d %s %s %s %s %s dc:%d pstruct:%d fdct:%d cmv:%d qtype:%d ivlc:%d rff:%d %s\n",

                     s->qscale, s->mpeg_f_code[0][0], s->mpeg_f_code[0][1], s->mpeg_f_code[1][0], s->mpeg_f_code[1][1],
                     s->pict_type == AV_PICTURE_TYPE_I ? "I" : (s->pict_type == AV_PICTURE_TYPE_P ? "P" : (s->pict_type == AV_PICTURE_TYPE_B ? "B" : "S")),
                     s->progressive_sequence ? "ps" :"", s->progressive_frame ? "pf" : "", s->alternate_scan ? "alt" :"", s->top_field_first ? "top" :"",
                     s->intra_dc_precision, s->picture_structure, s->frame_pred_frame_dct, s->concealment_motion_vectors,
                     s->q_scale_type, s->intra_vlc_format, s->repeat_first_field, s->chroma_420_type ? "420" :"");

         }

     }
 

     for (;;) {
         // If 1, we memcpy blocks in xvmcvideo.
         if (CONFIG_MPEG_XVMC_DECODER && s->avctx->xvmc_acceleration > 1)
             ff_xvmc_init_block(s); // set s->block

         if (mpeg_decode_mb(s, s->block) < 0)

             return -1;

         if (s->current_picture.f.motion_val[0] && !s->encoding) { // note motion_val is normally NULL unless we want to extract the MVs

             const int wrap = s->b8_stride;

             int xy         = s->mb_x * 2 + s->mb_y * 2 * wrap;
             int b8_xy      = 4 * (s->mb_x + s->mb_y * s->mb_stride);

             int motion_x, motion_y, dir, i;

             for (i = 0; i < 2; i++) {
                 for (dir = 0; dir < 2; dir++) {
                     if (s->mb_intra || (dir == 1 && s->pict_type != AV_PICTURE_TYPE_B)) {

                         motion_x = motion_y = 0;

                     } else if (s->mv_type == MV_TYPE_16X16 || (s->mv_type == MV_TYPE_FIELD && field_pic)) {

                         motion_x = s->mv[dir][0][0];
                         motion_y = s->mv[dir][0][1];
                     } else /*if ((s->mv_type == MV_TYPE_FIELD) || (s->mv_type == MV_TYPE_16X8))*/ {
                         motion_x = s->mv[dir][i][0];
                         motion_y = s->mv[dir][i][1];
                     }

                     s->current_picture.f.motion_val[dir][xy    ][0] = motion_x;
                     s->current_picture.f.motion_val[dir][xy    ][1] = motion_y;
                     s->current_picture.f.motion_val[dir][xy + 1][0] = motion_x;
                     s->current_picture.f.motion_val[dir][xy + 1][1] = motion_y;
                     s->current_picture.f.ref_index [dir][b8_xy    ] =
                     s->current_picture.f.ref_index [dir][b8_xy + 1] = s->field_select[dir][i];

                     av_assert2(s->field_select[dir][i] == 0 || s->field_select[dir][i] == 1);

                 }

                 xy += wrap;

                 b8_xy +=2;

             }
         }

         s->dest[0] += 16 >> lowres;
         s->dest[1] +=(16 >> lowres) >> s->chroma_x_shift;
         s->dest[2] +=(16 >> lowres) >> s->chroma_x_shift;

         ff_MPV_decode_mb(s, s->block);

         if (++s->mb_x >= s->mb_width) {

             const int mb_size = 16 >> s->avctx->lowres;

             ff_draw_horiz_band(s, mb_size*(s->mb_y >> field_pic), mb_size);

             ff_MPV_report_decode_progress(s);

 
             s->mb_x = 0;

             s->mb_y += 1 << field_pic;

             if (s->mb_y >= s->mb_height) {
                 int left   = get_bits_left(&s->gb);
                 int is_d10 = s->chroma_format == 2 && s->pict_type == AV_PICTURE_TYPE_I && avctx->profile == 0 && avctx->level == 5
                              && s->intra_dc_precision == 2 && s->q_scale_type == 1 && s->alternate_scan == 0
                              && s->progressive_frame == 0 /* vbv_delay == 0xBBB || 0xE10*/;

                 if (left < 0 || (left && show_bits(&s->gb, FFMIN(left, 23)) && !is_d10)

                     || ((avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_AGGRESSIVE)) && left > 8)) {

                     av_log(avctx, AV_LOG_ERROR, "end mismatch left=%d %0X\n", left, show_bits(&s->gb, FFMIN(left, 23)));

                     return -1;

                 } else

                     goto eos;
             }

             ff_init_block_index(s);

         }
 
         /* skip mb handling */

         if (s->mb_skip_run == -1) {

             /* read increment again */

             s->mb_skip_run = 0;

             for (;;) {

                 int code = get_vlc2(&s->gb, mbincr_vlc.table, MBINCR_VLC_BITS, 2);

                 if (code < 0) {

                     av_log(s->avctx, AV_LOG_ERROR, "mb incr damaged\n");

                     return -1;

                 }

                 if (code >= 33) {
                     if (code == 33) {

                         s->mb_skip_run += 33;

                     } else if (code == 35) {
                         if (s->mb_skip_run != 0 || show_bits(&s->gb, 15) != 0) {

                             av_log(s->avctx, AV_LOG_ERROR, "slice mismatch\n");

                             return -1;
                         }
                         goto eos; /* end of slice */

                     }
                     /* otherwise, stuffing, nothing to do */
                 } else {

                     s->mb_skip_run += code;

                     break;
                 }
             }

             if (s->mb_skip_run) {

                 int i;

                 if (s->pict_type == AV_PICTURE_TYPE_I) {

                     av_log(s->avctx, AV_LOG_ERROR, "skipped MB in I frame at %d %d\n", s->mb_x, s->mb_y);
                     return -1;
                 }
 
                 /* skip mb */
                 s->mb_intra = 0;

                 for (i = 0; i < 12; i++)

                     s->block_last_index[i] = -1;

                 if (s->picture_structure == PICT_FRAME)

                     s->mv_type = MV_TYPE_16X16;
                 else
                     s->mv_type = MV_TYPE_FIELD;

                 if (s->pict_type == AV_PICTURE_TYPE_P) {

                     /* if P type, zero motion vector is implied */

                     s->mv_dir             = MV_DIR_FORWARD;
                     s->mv[0][0][0]        = s->mv[0][0][1]      = 0;
                     s->last_mv[0][0][0]   = s->last_mv[0][0][1] = 0;
                     s->last_mv[0][1][0]   = s->last_mv[0][1][1] = 0;
                     s->field_select[0][0] = (s->picture_structure - 1) & 1;

                 } else {
                     /* if B type, reuse previous vectors and directions */
                     s->mv[0][0][0] = s->last_mv[0][0][0];
                     s->mv[0][0][1] = s->last_mv[0][0][1];
                     s->mv[1][0][0] = s->last_mv[1][0][0];
                     s->mv[1][0][1] = s->last_mv[1][0][1];
                 }
             }

         }

     }

 eos: // end of slice

     *buf += (get_bits_count(&s->gb)-1)/8;

 //printf("y %d %d %d %d\n", s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y);

     return 0;
 }

 static int slice_decode_thread(AVCodecContext *c, void *arg)
 {
     MpegEncContext *s   = *(void**)arg;
     const uint8_t *buf  = s->gb.buffer;
     int mb_y            = s->start_mb_y;
     const int field_pic = s->picture_structure != PICT_FRAME;

     s->error_count = (3 * (s->end_mb_y - s->start_mb_y) * s->mb_width) >> field_pic;

     for (;;) {

         uint32_t start_code;
         int ret;

         ret = mpeg_decode_slice(s, mb_y, &buf, s->gb.buffer_end - buf);

         emms_c();

 //av_log(c, AV_LOG_DEBUG, "ret:%d resync:%d/%d mb:%d/%d ts:%d/%d ec:%d\n",

 //ret, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, s->start_mb_y, s->end_mb_y, s->error_count);

         if (ret < 0) {

             if (c->err_recognition & AV_EF_EXPLODE)

                 return ret;

             if (s->resync_mb_x >= 0 && s->resync_mb_y >= 0)

                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_AC_ERROR | ER_DC_ERROR | ER_MV_ERROR);

         } else {

             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_AC_END | ER_DC_END | ER_MV_END);

         }

         if (s->mb_y == s->end_mb_y)

             return 0;

         start_code = -1;

         buf = avpriv_mpv_find_start_code(buf, s->gb.buffer_end, &start_code);

         mb_y= start_code - SLICE_MIN_START_CODE;

         if(s->codec_id != AV_CODEC_ID_MPEG1VIDEO && s->mb_height > 2800/16)

             mb_y += (*buf&0xE0)<<2;
         mb_y <<= field_pic;

         if (s->picture_structure == PICT_BOTTOM_FIELD)
             mb_y++;

         if (mb_y < 0 || mb_y >= s->end_mb_y)

             return -1;
     }
 }
 

 /**

  * Handle slice ends.

  * @return 1 if it seems to be the last slice

  */
 static int slice_end(AVCodecContext *avctx, AVFrame *pict)
 {
     Mpeg1Context *s1 = avctx->priv_data;
     MpegEncContext *s = &s1->mpeg_enc_ctx;

     if (!s1->mpeg_enc_ctx_allocated || !s->current_picture_ptr)

         return 0;
 

     if (s->avctx->hwaccel) {
         if (s->avctx->hwaccel->end_frame(s->avctx) < 0)
             av_log(avctx, AV_LOG_ERROR, "hardware accelerator failed to decode picture\n");
     }
 

     if (CONFIG_MPEG_XVMC_DECODER && s->avctx->xvmc_acceleration)

         ff_xvmc_field_end(s);

     /* end of slice reached */

     if (/*s->mb_y << field_pic == s->mb_height &&*/ !s->first_field && !s->first_slice) {

         /* end of image */

         s->current_picture_ptr->f.qscale_type = FF_QSCALE_TYPE_MPEG2;

         ff_er_frame_end(s);

         ff_MPV_frame_end(s);

         if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {

             *pict = s->current_picture_ptr->f;

             ff_print_debug_info(s, pict);

         } else {

             if (avctx->active_thread_type & FF_THREAD_FRAME)

                 s->picture_number++;

             /* latency of 1 frame for I- and P-frames */

             /* XXX: use another variable than picture_number */

             if (s->last_picture_ptr != NULL) {

                 *pict = s->last_picture_ptr->f;

                  ff_print_debug_info(s, pict);

             }
         }

 
         return 1;
     } else {
         return 0;

     }
 }
 

 static int mpeg1_decode_sequence(AVCodecContext *avctx,

                                  const uint8_t *buf, int buf_size)

 {
     Mpeg1Context *s1 = avctx->priv_data;
     MpegEncContext *s = &s1->mpeg_enc_ctx;

     int width, height;

     int i, v, j;

     init_get_bits(&s->gb, buf, buf_size*8);

     width  = get_bits(&s->gb, 12);

     height = get_bits(&s->gb, 12);

     if (width <= 0 || height <= 0)

         return -1;

     s->aspect_ratio_info = get_bits(&s->gb, 4);

     if (s->aspect_ratio_info == 0) {
         av_log(avctx, AV_LOG_ERROR, "aspect ratio has forbidden 0 value\n");

         if (avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_COMPLIANT))

             return -1;
     }

     s->frame_rate_index = get_bits(&s->gb, 4);

     if (s->frame_rate_index == 0 || s->frame_rate_index > 13)

         return -1;
     s->bit_rate = get_bits(&s->gb, 18) * 400;

     if (get_bits1(&s->gb) == 0) /* marker */

         return -1;

     s->width  = width;

     s->height = height;

     s->avctx->rc_buffer_size = get_bits(&s->gb, 10) * 1024 * 16;

     skip_bits(&s->gb, 1);

 
     /* get matrix */

     if (get_bits1(&s->gb)) {

         load_matrix(s, s->chroma_intra_matrix, s->intra_matrix, 1);

     } else {

         for (i = 0; i < 64; i++) {

             j = s->dsp.idct_permutation[i];

             v = ff_mpeg1_default_intra_matrix[i];

             s->intra_matrix[j]        = v;

             s->chroma_intra_matrix[j] = v;

         }
     }

     if (get_bits1(&s->gb)) {

         load_matrix(s, s->chroma_inter_matrix, s->inter_matrix, 0);

     } else {

         for (i = 0; i < 64; i++) {
             int j = s->dsp.idct_permutation[i];

             v = ff_mpeg1_default_non_intra_matrix[i];

             s->inter_matrix[j]        = v;

             s->chroma_inter_matrix[j] = v;

         }
     }

     if (show_bits(&s->gb, 23) != 0) {

         av_log(s->avctx, AV_LOG_ERROR, "sequence header damaged\n");
         return -1;
     }

     /* we set MPEG-2 parameters so that it emulates MPEG-1 */

     s->progressive_sequence = 1;

     s->progressive_frame    = 1;
     s->picture_structure    = PICT_FRAME;

     s->first_field          = 0;

     s->frame_pred_frame_dct = 1;

     s->chroma_format        = 1;

     s->codec_id             = s->avctx->codec_id = AV_CODEC_ID_MPEG1VIDEO;

     s->out_format           = FMT_MPEG1;
     s->swap_uv              = 0; // AFAIK VCR2 does not have SEQ_HEADER
     if (s->flags & CODEC_FLAG_LOW_DELAY)
         s->low_delay = 1;
 
     if (s->avctx->debug & FF_DEBUG_PICT_INFO)

         av_log(s->avctx, AV_LOG_DEBUG, "vbv buffer: %d, bitrate:%d\n",

                s->avctx->rc_buffer_size, s->bit_rate);

     return 0;
 }
 

 static int vcr2_init_sequence(AVCodecContext *avctx)
 {
     Mpeg1Context *s1 = avctx->priv_data;
     MpegEncContext *s = &s1->mpeg_enc_ctx;

     int i, v;

     /* start new MPEG-1 context decoding */

     s->out_format = FMT_MPEG1;
     if (s1->mpeg_enc_ctx_allocated) {

         ff_MPV_common_end(s);

     }

     s->width  = avctx->coded_width;
     s->height = avctx->coded_height;

     avctx->has_b_frames = 0; // true?
     s->low_delay = 1;

     avctx->pix_fmt = mpeg_get_pixelformat(avctx);

     avctx->hwaccel = ff_find_hwaccel(avctx->codec->id, avctx->pix_fmt);

     if( avctx->pix_fmt == PIX_FMT_XVMC_MPEG2_IDCT || avctx->hwaccel )

         if (avctx->idct_algo == FF_IDCT_AUTO)

             avctx->idct_algo = FF_IDCT_SIMPLE;

     if (ff_MPV_common_init(s) < 0)

         return -1;
     s1->mpeg_enc_ctx_allocated = 1;
 

     for (i = 0; i < 64; i++) {
         int j = s->dsp.idct_permutation[i];

         v = ff_mpeg1_default_intra_matrix[i];

         s->intra_matrix[j]        = v;

         s->chroma_intra_matrix[j] = v;
 
         v = ff_mpeg1_default_non_intra_matrix[i];

         s->inter_matrix[j]        = v;

         s->chroma_inter_matrix[j] = v;
     }
 

     s->progressive_sequence  = 1;
     s->progressive_frame     = 1;
     s->picture_structure     = PICT_FRAME;

     s->first_field           = 0;

     s->frame_pred_frame_dct  = 1;
     s->chroma_format         = 1;

     if (s->codec_tag == AV_RL32("BW10")) {

         s->codec_id              = s->avctx->codec_id = AV_CODEC_ID_MPEG1VIDEO;

     } else {
         exchange_uv(s); // common init reset pblocks, so we swap them here
         s->swap_uv = 1; // in case of xvmc we need to swap uv for each MB

         s->codec_id              = s->avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO;

     }

     s1->save_width           = s->width;
     s1->save_height          = s->height;
     s1->save_progressive_seq = s->progressive_sequence;

     return 0;
 }
 
 

 static void mpeg_decode_user_data(AVCodecContext *avctx,

                                   const uint8_t *p, int buf_size)

 {

     Mpeg1Context *s = avctx->priv_data;

     const uint8_t *buf_end = p + buf_size;

     if(buf_size > 29){
         int i;
         for(i=0; i<20; i++)
             if(!memcmp(p+i, "\0TMPGEXS\0", 9)){
                 s->tmpgexs= 1;
             }
 
 /*        for(i=0; !(!p[i-2] && !p[i-1] && p[i]==1) && i<buf_size; i++){
             av_log(0,0, "%c", p[i]);
         }
             av_log(0,0, "\n");*/
     }
 

     /* we parse the DTG active format information */

     if (buf_end - p >= 5 &&

         p[0] == 'D' && p[1] == 'T' && p[2] == 'G' && p[3] == '1') {

         int flags = p[4];

         p += 5;
         if (flags & 0x80) {
             /* skip event id */
             p += 2;
         }
         if (flags & 0x40) {

             if (buf_end - p < 1)

                 return;
             avctx->dtg_active_format = p[0] & 0x0f;
         }
     }
 }
 

 static void mpeg_decode_gop(AVCodecContext *avctx,

                             const uint8_t *buf, int buf_size)
 {
     Mpeg1Context *s1  = avctx->priv_data;

     MpegEncContext *s = &s1->mpeg_enc_ctx;

     int broken_link;

     int64_t tc;

 
     init_get_bits(&s->gb, buf, buf_size*8);
 

     tc = avctx->timecode_frame_start = get_bits(&s->gb, 25);

     s->closed_gop = get_bits1(&s->gb);

     /*broken_link indicate that after editing the
       reference frames of the first B-Frames after GOP I-Frame
       are missing (open gop)*/
     broken_link = get_bits1(&s->gb);
 

     if (s->avctx->debug & FF_DEBUG_PICT_INFO) {

         char tcbuf[AV_TIMECODE_STR_SIZE];
         av_timecode_make_mpeg_tc_string(tcbuf, tc);
         av_log(s->avctx, AV_LOG_DEBUG,
                "GOP (%s) closed_gop=%d broken_link=%d\n",
                tcbuf, s->closed_gop, broken_link);

     }

 }

 /**

  * Find the end of the current frame in the bitstream.

  * @return the position of the first byte of the next frame, or -1
  */

 int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)

 {

     int i;

     uint32_t state = pc->state;

     /* EOF considered as end of frame */
     if (buf_size == 0)
         return 0;
 
 /*
  0  frame start         -> 1/4
  1  first_SEQEXT        -> 0/2
  2  first field start   -> 3/0
  3  second_SEQEXT       -> 2/0
  4  searching end
 */
 

     for (i = 0; i < buf_size; i++) {

         av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);

         if (pc->frame_start_found & 1) {
             if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)

                 pc->frame_start_found--;

             else if (state == EXT_START_CODE + 2) {
                 if ((buf[i] & 3) == 3)
                     pc->frame_start_found = 0;
                 else
                     pc->frame_start_found = (pc->frame_start_found + 1) & 3;

             }
             state++;

         } else {

             i = avpriv_mpv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;

             if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {

                 i++;

                 pc->frame_start_found = 4;

             }

             if (state == SEQ_END_CODE) {

                 pc->frame_start_found = 0;

                 pc->state=-1;
                 return i+1;
             }

             if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
                 pc->frame_start_found = 0;
             if (pc->frame_start_found  < 4 && state == EXT_START_CODE)

                 pc->frame_start_found++;

             if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
                 if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
                     pc->frame_start_found = 0;
                     pc->state             = -1;
                     return i - 3;

                 }
             }

             if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
                 ff_fetch_timestamp(s, i - 3, 1);

             }

         }

     }

     pc->state = state;

     return END_NOT_FOUND;

 }
 

 static int decode_chunks(AVCodecContext *avctx,

                          AVFrame *picture, int *data_size,
                          const uint8_t *buf, int buf_size);

 /* handle buffering and image synchronisation */

 static int mpeg_decode_frame(AVCodecContext *avctx,

                              void *data, int *data_size,

                              AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     Mpeg1Context *s = avctx->priv_data;

     AVFrame *picture = data;

     MpegEncContext *s2 = &s->mpeg_enc_ctx;

     av_dlog(avctx, "fill_buffer\n");

     if (buf_size == 0 || (buf_size == 4 && AV_RB32(buf) == SEQ_END_CODE)) {

         /* special case for last picture */

         if (s2->low_delay == 0 && s2->next_picture_ptr) {

             *picture = s2->next_picture_ptr->f;

             s2->next_picture_ptr = NULL;

             *data_size = sizeof(AVFrame);
         }

         return buf_size;

     }
 

     if (s2->flags & CODEC_FLAG_TRUNCATED) {
         int next = ff_mpeg1_find_frame_end(&s2->parse_context, buf, buf_size, NULL);

         if (ff_combine_frame(&s2->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0)

             return buf_size;

     }
 

     s2->codec_tag = avpriv_toupper4(avctx->codec_tag);

     if (s->mpeg_enc_ctx_allocated == 0 && (   s2->codec_tag == AV_RL32("VCR2")
                                            || s2->codec_tag == AV_RL32("BW10")
                                           ))

         vcr2_init_sequence(avctx);

     s->slice_count = 0;

     if (avctx->extradata && !s->parsed_extra) {

         int ret = decode_chunks(avctx, picture, data_size, avctx->extradata, avctx->extradata_size);

         if(*data_size) {
             av_log(avctx, AV_LOG_ERROR, "picture in extradata\n");
             *data_size = 0;
         }

         s->parsed_extra = 1;

         if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))

             return ret;
     }

     return decode_chunks(avctx, picture, data_size, buf, buf_size);
 }
 
 static int decode_chunks(AVCodecContext *avctx,

                          AVFrame *picture, int *data_size,
                          const uint8_t *buf, int buf_size)

 {
     Mpeg1Context *s = avctx->priv_data;
     MpegEncContext *s2 = &s->mpeg_enc_ctx;
     const uint8_t *buf_ptr = buf;
     const uint8_t *buf_end = buf + buf_size;
     int ret, input_size;

     int last_code = 0;

     for (;;) {

         /* find next start code */

         uint32_t start_code = -1;

         buf_ptr = avpriv_mpv_find_start_code(buf_ptr, buf_end, &start_code);

         if (start_code > 0x1ff) {
             if (s2->pict_type != AV_PICTURE_TYPE_B || avctx->skip_frame <= AVDISCARD_DEFAULT) {
                 if (HAVE_THREADS && (avctx->active_thread_type & FF_THREAD_SLICE)) {

                     int i;

                     av_assert0(avctx->thread_count > 1);

                     avctx->execute(avctx, slice_decode_thread,  &s2->thread_context[0], NULL, s->slice_count, sizeof(void*));

                     for (i = 0; i < s->slice_count; i++)

                         s2->error_count += s2->thread_context[i]->error_count;
                 }

                 if (CONFIG_VDPAU && uses_vdpau(avctx))

                     ff_vdpau_mpeg_picture_complete(s2, buf, buf_size, s->slice_count);

                 if (slice_end(avctx, picture)) {

                     if (s2->last_picture_ptr || s2->low_delay) //FIXME merge with the stuff in mpeg_decode_slice

                         *data_size = sizeof(AVPicture);
                 }

             }

             s2->pict_type = 0;

             return FFMAX(0, buf_ptr - buf - s2->parse_context.last_index);

         }

         input_size = buf_end - buf_ptr;
 

         if (avctx->debug & FF_DEBUG_STARTCODE) {

             av_log(avctx, AV_LOG_DEBUG, "%3X at %td left %d\n", start_code, buf_ptr-buf, input_size);

         }

         /* prepare data for next start code */

         switch (start_code) {

         case SEQ_START_CODE:

             if (last_code == 0) {
                 mpeg1_decode_sequence(avctx, buf_ptr, input_size);

                 if(buf != avctx->extradata)
                     s->sync=1;

             } else {

                 av_log(avctx, AV_LOG_ERROR, "ignoring SEQ_START_CODE after %X\n", last_code);

                 if (avctx->err_recognition & AV_EF_EXPLODE)

                     return AVERROR_INVALIDDATA;

             }

             break;

         case PICTURE_START_CODE:

             if(s->tmpgexs){
                 s2->intra_dc_precision= 3;
                 s2->intra_matrix[0]= 1;
             }

             if (HAVE_THREADS && (avctx->active_thread_type & FF_THREAD_SLICE) && s->slice_count) {

                 int i;
 
                 avctx->execute(avctx, slice_decode_thread,
                                s2->thread_context, NULL,
                                s->slice_count, sizeof(void*));
                 for (i = 0; i < s->slice_count; i++)
                     s2->error_count += s2->thread_context[i]->error_count;
                 s->slice_count = 0;
             }

             if (last_code == 0 || last_code == SLICE_MIN_START_CODE) {

                 ret = mpeg_decode_postinit(avctx);

                 if (ret < 0) {

                     av_log(avctx, AV_LOG_ERROR, "mpeg_decode_postinit() failure\n");
                     return ret;
                 }

                 /* we have a complete image: we try to decompress it */
                 if (mpeg1_decode_picture(avctx, buf_ptr, input_size) < 0)

                     s2->pict_type = 0;

                 s2->first_slice = 1;

                 last_code = PICTURE_START_CODE;
             } else {

                 av_log(avctx, AV_LOG_ERROR, "ignoring pic after %X\n", last_code);

                 if (avctx->err_recognition & AV_EF_EXPLODE)

                     return AVERROR_INVALIDDATA;

             }

             break;
         case EXT_START_CODE:

             init_get_bits(&s2->gb, buf_ptr, input_size*8);
 

             switch (get_bits(&s2->gb, 4)) {

             case 0x1:

                 if (last_code == 0) {

                 mpeg_decode_sequence_extension(s);

                 } else {

                     av_log(avctx, AV_LOG_ERROR, "ignoring seq ext after %X\n", last_code);

                     if (avctx->err_recognition & AV_EF_EXPLODE)

                         return AVERROR_INVALIDDATA;

                 }

                 break;
             case 0x2:
                 mpeg_decode_sequence_display_extension(s);
                 break;
             case 0x3:
                 mpeg_decode_quant_matrix_extension(s2);
                 break;
             case 0x7:
                 mpeg_decode_picture_display_extension(s);
                 break;
             case 0x8:

                 if (last_code == PICTURE_START_CODE) {
                     mpeg_decode_picture_coding_extension(s);
                 } else {

                     av_log(avctx, AV_LOG_ERROR, "ignoring pic cod ext after %X\n", last_code);

                     if (avctx->err_recognition & AV_EF_EXPLODE)

                         return AVERROR_INVALIDDATA;

                 }

                 break;
             }

             break;
         case USER_START_CODE:

             mpeg_decode_user_data(avctx, buf_ptr, input_size);

             break;
         case GOP_START_CODE:

             if (last_code == 0) {

                 s2->first_field=0;
                 mpeg_decode_gop(avctx, buf_ptr, input_size);

                 s->sync=1;

             } else {

                 av_log(avctx, AV_LOG_ERROR, "ignoring GOP_START_CODE after %X\n", last_code);

                 if (avctx->err_recognition & AV_EF_EXPLODE)

                     return AVERROR_INVALIDDATA;

             }

             break;
         default:
             if (start_code >= SLICE_MIN_START_CODE &&

                 start_code <= SLICE_MAX_START_CODE && last_code == PICTURE_START_CODE) {
 
                 if (s2->progressive_sequence && !s2->progressive_frame) {
                     s2->progressive_frame = 1;
                     av_log(s2->avctx, AV_LOG_ERROR, "interlaced frame in progressive sequence, ignoring\n");
                 }
 
                 if (s2->picture_structure == 0 || (s2->progressive_frame && s2->picture_structure != PICT_FRAME)) {
                     av_log(s2->avctx, AV_LOG_ERROR, "picture_structure %d invalid, ignoring\n", s2->picture_structure);
                     s2->picture_structure = PICT_FRAME;
                 }
 
                 if (s2->progressive_sequence && !s2->frame_pred_frame_dct) {
                     av_log(s2->avctx, AV_LOG_WARNING, "invalid frame_pred_frame_dct\n");
                 }
 
                 if (s2->picture_structure == PICT_FRAME) {
                     s2->first_field = 0;
                     s2->v_edge_pos  = 16 * s2->mb_height;
                 } else {
                     s2->first_field ^= 1;
                     s2->v_edge_pos   = 8 * s2->mb_height;
                     memset(s2->mbskip_table, 0, s2->mb_stride * s2->mb_height);
                 }
             }
             if (start_code >= SLICE_MIN_START_CODE &&

                 start_code <= SLICE_MAX_START_CODE && last_code != 0) {
                 const int field_pic = s2->picture_structure != PICT_FRAME;

                 int mb_y = start_code - SLICE_MIN_START_CODE;

                 last_code = SLICE_MIN_START_CODE;

                 if(s2->codec_id != AV_CODEC_ID_MPEG1VIDEO && s2->mb_height > 2800/16)

                     mb_y += (*buf_ptr&0xE0)<<2;

                 mb_y <<= field_pic;

                 if (s2->picture_structure == PICT_BOTTOM_FIELD)

                     mb_y++;
 

                 if (mb_y >= s2->mb_height) {

                     av_log(s2->avctx, AV_LOG_ERROR, "slice below image (%d >= %d)\n", mb_y, s2->mb_height);
                     return -1;
                 }
 

                 if (s2->last_picture_ptr == NULL) {

                 /* Skip B-frames if we do not have reference frames and gop is not closed */

                     if (s2->pict_type == AV_PICTURE_TYPE_B) {

                         if (!s2->closed_gop)

                             break;
                     }

                 }

                 if (s2->pict_type == AV_PICTURE_TYPE_I || (s2->flags2 & CODEC_FLAG2_SHOW_ALL))

                     s->sync=1;

                 if (s2->next_picture_ptr == NULL) {

                 /* Skip P-frames if we do not have a reference frame or we have an invalid header. */

                     if (s2->pict_type == AV_PICTURE_TYPE_P && !s->sync) break;

                 }

                 if ((avctx->skip_frame >= AVDISCARD_NONREF && s2->pict_type == AV_PICTURE_TYPE_B) ||
                     (avctx->skip_frame >= AVDISCARD_NONKEY && s2->pict_type != AV_PICTURE_TYPE_I) ||
                      avctx->skip_frame >= AVDISCARD_ALL)

                     break;

                 if (!s->mpeg_enc_ctx_allocated)
                     break;

                 if (s2->codec_id == AV_CODEC_ID_MPEG2VIDEO) {

                     if (mb_y < avctx->skip_top || mb_y >= s2->mb_height - avctx->skip_bottom)

                         break;
                 }

                 if (!s2->pict_type) {

                     av_log(avctx, AV_LOG_ERROR, "Missing picture start code\n");

                     if (avctx->err_recognition & AV_EF_EXPLODE)

                         return AVERROR_INVALIDDATA;

                     break;
                 }
 

                 if (s2->first_slice) {
                     s2->first_slice = 0;
                     if (mpeg_field_start(s2, buf, buf_size) < 0)

                         return -1;

                 }

                 if (!s2->current_picture_ptr) {

                     av_log(avctx, AV_LOG_ERROR, "current_picture not initialized\n");

                     return AVERROR_INVALIDDATA;

                 }

                 if (uses_vdpau(avctx)) {

                     s->slice_count++;
                     break;
                 }
 

                 if (HAVE_THREADS && (avctx->active_thread_type & FF_THREAD_SLICE)) {

                     int threshold = (s2->mb_height * s->slice_count +
                                      s2->slice_context_count / 2) /
                                     s2->slice_context_count;

                     av_assert0(avctx->thread_count > 1);

                     if (threshold <= mb_y) {
                         MpegEncContext *thread_context = s2->thread_context[s->slice_count];

                         thread_context->start_mb_y = mb_y;
                         thread_context->end_mb_y   = s2->mb_height;
                         if (s->slice_count) {
                             s2->thread_context[s->slice_count-1]->end_mb_y = mb_y;

                             ff_update_duplicate_context(thread_context, s2);

                         }

                         init_get_bits(&thread_context->gb, buf_ptr, input_size*8);
                         s->slice_count++;
                     }

                     buf_ptr += 2; // FIXME add minimum number of bytes per slice
                 } else {

                     ret = mpeg_decode_slice(s2, mb_y, &buf_ptr, input_size);

                     emms_c();
 

                     if (ret < 0) {

                         if (avctx->err_recognition & AV_EF_EXPLODE)

                             return ret;

                         if (s2->resync_mb_x >= 0 && s2->resync_mb_y >= 0)

                             ff_er_add_slice(s2, s2->resync_mb_x, s2->resync_mb_y, s2->mb_x, s2->mb_y, ER_AC_ERROR | ER_DC_ERROR | ER_MV_ERROR);

                     } else {

                         ff_er_add_slice(s2, s2->resync_mb_x, s2->resync_mb_y, s2->mb_x-1, s2->mb_y, ER_AC_END | ER_DC_END | ER_MV_END);

                     }
                 }

             }
             break;
         }

     }
 }
 

 static void flush(AVCodecContext *avctx)
 {

     Mpeg1Context *s = avctx->priv_data;
 
     s->sync=0;
 
     ff_mpeg_flush(avctx);
 }
 

 static int mpeg_decode_end(AVCodecContext *avctx)
 {
     Mpeg1Context *s = avctx->priv_data;
 
     if (s->mpeg_enc_ctx_allocated)

         ff_MPV_common_end(&s->mpeg_enc_ctx);

     return 0;
 }
 

 static const AVProfile mpeg2_video_profiles[] = {
     { FF_PROFILE_MPEG2_422,          "4:2:2"              },
     { FF_PROFILE_MPEG2_HIGH,         "High"               },
     { FF_PROFILE_MPEG2_SS,           "Spatially Scalable" },
     { FF_PROFILE_MPEG2_SNR_SCALABLE, "SNR Scalable"       },
     { FF_PROFILE_MPEG2_MAIN,         "Main"               },
     { FF_PROFILE_MPEG2_SIMPLE,       "Simple"             },
     { FF_PROFILE_RESERVED,           "Reserved"           },
     { FF_PROFILE_RESERVED,           "Reserved"           },

     { FF_PROFILE_UNKNOWN },

 };
 
 

 AVCodec ff_mpeg1video_decoder = {

     .name                  = "mpeg1video",
     .type                  = AVMEDIA_TYPE_VIDEO,

     .id                    = AV_CODEC_ID_MPEG1VIDEO,

     .priv_data_size        = sizeof(Mpeg1Context),
     .init                  = mpeg_decode_init,
     .close                 = mpeg_decode_end,
     .decode                = mpeg_decode_frame,
     .capabilities          = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
                              CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
                              CODEC_CAP_SLICE_THREADS,
     .flush                 = flush,

     .max_lowres            = 3,

     .long_name             = NULL_IF_CONFIG_SMALL("MPEG-1 video"),

     .update_thread_context = ONLY_IF_THREADS_ENABLED(mpeg_decode_update_thread_context)

 };
 

 AVCodec ff_mpeg2video_decoder = {

     .name           = "mpeg2video",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_MPEG2VIDEO,

     .priv_data_size = sizeof(Mpeg1Context),
     .init           = mpeg_decode_init,
     .close          = mpeg_decode_end,
     .decode         = mpeg_decode_frame,

     .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
                       CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
                       CODEC_CAP_SLICE_THREADS,

     .flush          = flush,

     .max_lowres     = 3,

     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-2 video"),
     .profiles       = NULL_IF_CONFIG_SMALL(mpeg2_video_profiles),

 };
 
 //legacy decoder

 AVCodec ff_mpegvideo_decoder = {

     .name           = "mpegvideo",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_MPEG2VIDEO,

     .priv_data_size = sizeof(Mpeg1Context),
     .init           = mpeg_decode_init,
     .close          = mpeg_decode_end,
     .decode         = mpeg_decode_frame,
     .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY | CODEC_CAP_SLICE_THREADS,

     .flush          = flush,
     .max_lowres     = 3,
     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-1 video"),

 };

 #if CONFIG_MPEG_XVMC_DECODER

 static av_cold int mpeg_mc_decode_init(AVCodecContext *avctx)
 {
     if (avctx->active_thread_type & FF_THREAD_SLICE)

         return -1;

     if (!(avctx->slice_flags & SLICE_FLAG_CODED_ORDER))

         return -1;

     if (!(avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD)) {

         av_dlog(avctx, "mpeg12.c: XvMC decoder will work better if SLICE_FLAG_ALLOW_FIELD is set\n");

     }

     mpeg_decode_init(avctx);
 

     avctx->pix_fmt           = PIX_FMT_XVMC_MPEG2_IDCT;
     avctx->xvmc_acceleration = 2; // 2 - the blocks are packed!

 
     return 0;
 }
 

 AVCodec ff_mpeg_xvmc_decoder = {

     .name           = "mpegvideo_xvmc",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_MPEG2VIDEO_XVMC,

     .priv_data_size = sizeof(Mpeg1Context),
     .init           = mpeg_mc_decode_init,
     .close          = mpeg_decode_end,
     .decode         = mpeg_decode_frame,

     .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
                       CODEC_CAP_TRUNCATED| CODEC_CAP_HWACCEL | CODEC_CAP_DELAY,

     .flush          = flush,
     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-1/2 video XvMC (X-Video Motion Compensation)"),

 };
 
 #endif

 
 #if CONFIG_MPEG_VDPAU_DECODER

 AVCodec ff_mpeg_vdpau_decoder = {

     .name           = "mpegvideo_vdpau",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_MPEG2VIDEO,

     .priv_data_size = sizeof(Mpeg1Context),
     .init           = mpeg_decode_init,
     .close          = mpeg_decode_end,
     .decode         = mpeg_decode_frame,

     .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED |
                       CODEC_CAP_HWACCEL_VDPAU | CODEC_CAP_DELAY,

     .flush          = flush,
     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-1/2 video (VDPAU acceleration)"),

 };
 #endif
 

 #if CONFIG_MPEG1_VDPAU_DECODER

 AVCodec ff_mpeg1_vdpau_decoder = {

     .name           = "mpeg1video_vdpau",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_MPEG1VIDEO,

     .priv_data_size = sizeof(Mpeg1Context),
     .init           = mpeg_decode_init,
     .close          = mpeg_decode_end,
     .decode         = mpeg_decode_frame,

     .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED |
                       CODEC_CAP_HWACCEL_VDPAU | CODEC_CAP_DELAY,

     .flush          = flush,
     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-1 video (VDPAU acceleration)"),

 };
 #endif