/*
  * MPEG-1/2 decoder
  * Copyright (c) 2000, 2001 Fabrice Bellard

  * Copyright (c) 2002-2013 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

 #include <inttypes.h>
 

 #include "libavutil/attributes.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/internal.h"

 #include "libavutil/stereo3d.h"

 #include "avcodec.h"

 #include "bytestream.h"

 #include "error_resilience.h"

 #include "hwaccel.h"

 #include "idctdsp.h"

 #include "internal.h"

 #include "mpeg_er.h"

 #include "mpeg12.h"
 #include "mpeg12data.h"

 #include "mpegutils.h"

 #include "mpegvideo.h"

 #include "mpegvideodata.h"

 #include "profiles.h"

 #include "thread.h"

 #include "version.h"

 #include "xvmc_internal.h"

 typedef struct Mpeg1Context {
     MpegEncContext mpeg_enc_ctx;
     int mpeg_enc_ctx_allocated; /* true if decoding context allocated */

     int repeat_field;           /* true if we must repeat the field */
     AVPanScan pan_scan;         /* some temporary storage for the panscan */

     AVStereo3D stereo3d;
     int has_stereo3d;

     uint8_t *a53_caption;
     int a53_caption_size;

     uint8_t afd;
     int has_afd;

     int slice_count;

     AVRational save_aspect;

     int save_width, save_height, save_progressive_seq;

     AVRational frame_rate_ext;  /* MPEG-2 specific framerate modificator */
     int sync;                   /* Did we reach a sync point like a GOP/SEQ/KEYFrame? */

     int tmpgexs;

     int first_slice;

     int extradata_decoded;
 } Mpeg1Context;
 

 #define MB_TYPE_ZERO_MV   0x20000000
 
 static const uint32_t ptype2mb_type[7] = {
                     MB_TYPE_INTRA,
                     MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_ZERO_MV | MB_TYPE_16x16,
                     MB_TYPE_L0,
                     MB_TYPE_L0 | MB_TYPE_CBP,
     MB_TYPE_QUANT | MB_TYPE_INTRA,
     MB_TYPE_QUANT | MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_ZERO_MV | MB_TYPE_16x16,
     MB_TYPE_QUANT | MB_TYPE_L0 | MB_TYPE_CBP,
 };
 
 static const uint32_t btype2mb_type[11] = {
                     MB_TYPE_INTRA,
                     MB_TYPE_L1,
                     MB_TYPE_L1   | MB_TYPE_CBP,
                     MB_TYPE_L0,
                     MB_TYPE_L0   | MB_TYPE_CBP,
                     MB_TYPE_L0L1,
                     MB_TYPE_L0L1 | MB_TYPE_CBP,
     MB_TYPE_QUANT | MB_TYPE_INTRA,
     MB_TYPE_QUANT | MB_TYPE_L1   | MB_TYPE_CBP,
     MB_TYPE_QUANT | MB_TYPE_L0   | MB_TYPE_CBP,
     MB_TYPE_QUANT | MB_TYPE_L0L1 | MB_TYPE_CBP,
 };
 

 /* 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, ff_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);
 }
 

 #define MAX_INDEX (64 - 1)

 #define check_scantable_index(ctx, x)                                         \
     do {                                                                      \

         if ((x) > MAX_INDEX) {                                                \

             av_log(ctx->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n",     \
                    ctx->mb_x, ctx->mb_y);                                     \
             return AVERROR_INVALIDDATA;                                       \
         }                                                                     \
     } while (0)
 
 static inline int mpeg1_decode_block_inter(MpegEncContext *s,
                                            int16_t *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;

                 if (i > MAX_INDEX)
                     break;

                 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;

                 if (i > MAX_INDEX)
                     break;

                 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;
                 }
             }
 
             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);
     }

 
     check_scantable_index(s, i);
 

     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,
                                                 int16_t *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;

                 if (i > MAX_INDEX)
                     break;

                 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;

                 if (i > MAX_INDEX)
                     break;

                 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);
     }

 
     check_scantable_index(s, i);
 

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

 static inline int mpeg2_decode_block_non_intra(MpegEncContext *s,
                                                int16_t *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;

                 if (i > MAX_INDEX)
                     break;

                 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;

                 if (i > MAX_INDEX)
                     break;

                 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;
                 }
             }
 
             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);
 

     check_scantable_index(s, i);
 

     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,
                                                     int16_t *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;

             if (i > MAX_INDEX)
                 break;

             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;

             if (i > MAX_INDEX)
                 break;

             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 || i > 63)

             break;

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

 
     check_scantable_index(s, i);
 

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

 static inline int mpeg2_decode_block_intra(MpegEncContext *s,
                                            int16_t *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 AVERROR_INVALIDDATA;

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

     block[0] = dc * (1 << (3 - s->intra_dc_precision));

     ff_tlog(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;

                 if (i > MAX_INDEX)
                     break;

                 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;

                 if (i > MAX_INDEX)
                     break;

                 j = scantable[i];

                 if (level < 0) {
                     level = (-level * qscale * quant_matrix[j]) >> 4;
                     level = -level;
                 } else {
                     level = (level * qscale * quant_matrix[j]) >> 4;
                 }
             }
 
             mismatch ^= level;
             block[j]  = level;
         }
         CLOSE_READER(re, &s->gb);
     }
     block[63] ^= mismatch & 1;
 

     check_scantable_index(s, i);
 

     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,
                                                 int16_t *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;
 
     /* 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 AVERROR_INVALIDDATA;

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

     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 >= 64 || i > 63) {

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

     check_scantable_index(s, i);
 

     s->block_last_index[n] = i;

     return 0;
 }
 
 /******************************************/
 /* decoding */
 
 static inline int get_dmv(MpegEncContext *s)
 {
     if (get_bits1(&s->gb))
         return 1 - (get_bits1(&s->gb) << 1);
     else
         return 0;
 }
 
 /* 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, int16_t block[12][64])
 {
     int i, j, k, cbp, val, mb_type, motion_type;
     const int mb_block_count = 4 + (1 << s->chroma_format);

     int ret;

     ff_tlog(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.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.mb_type[s->mb_x + s->mb_y * s->mb_stride - 1];
             else

                 // FIXME not sure if this is allowed in MPEG at all
                 mb_type = s->current_picture.mb_type[s->mb_width + (s->mb_y - 1) * s->mb_stride - 1];

             if (IS_INTRA(mb_type)) {
                 av_log(s->avctx, AV_LOG_ERROR, "skip with previntra\n");

                 return AVERROR_INVALIDDATA;

             }

             s->current_picture.mb_type[s->mb_x + s->mb_y * s->mb_stride] =

                 mb_type | MB_TYPE_SKIP;

             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 AVERROR_INVALIDDATA;

             }
             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, ff_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 AVERROR_INVALIDDATA;

         }
         mb_type = ptype2mb_type[mb_type];
         break;
     case AV_PICTURE_TYPE_B:
         mb_type = get_vlc2(&s->gb, ff_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 AVERROR_INVALIDDATA;

         }
         mb_type = btype2mb_type[mb_type];
         break;
     }

     ff_tlog(s->avctx, "mb_type=%x\n", mb_type);

 //    motion_type = 0; /* avoid warning */
     if (IS_INTRA(mb_type)) {

         s->bdsp.clear_blocks(s->block[0]);

         if (!s->chroma_y_shift)

             s->bdsp.clear_blocks(s->block[6]);

 
         /* compute DCT type */

         // FIXME: add an interlaced_dct coded var?
         if (s->picture_structure == PICT_FRAME &&
             !s->frame_pred_frame_dct)

             s->interlaced_dct = get_bits1(&s->gb);
 
         if (IS_QUANT(mb_type))

             s->qscale = mpeg_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]);

             check_marker(s->avctx, &s->gb, "after concealment_motion_vectors");

         } else {
             /* reset mv prediction */
             memset(s->last_mv, 0, sizeof(s->last_mv));
         }

         s->mb_intra = 1;
         // if 1, we memcpy blocks in xvmcvideo

         if ((CONFIG_MPEG1_XVMC_HWACCEL || CONFIG_MPEG2_XVMC_HWACCEL) && s->pack_pblocks)

             ff_xvmc_pack_pblocks(s, -1); // inter are always full blocks
 
         if (s->codec_id == AV_CODEC_ID_MPEG2VIDEO) {

             if (s->avctx->flags2 & AV_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 ((ret = mpeg2_decode_block_intra(s, *s->pblocks[i], i)) < 0)
                         return ret;

             }
         } else {

             for (i = 0; i < 6; i++) {
                 ret = ff_mpeg1_decode_block_intra(&s->gb,
                                                   s->intra_matrix,
                                                   s->intra_scantable.permutated,
                                                   s->last_dc, *s->pblocks[i],

                                                   i, s->qscale);

                 if (ret < 0) {
                     av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n",
                            s->mb_x, s->mb_y);

                     return ret;

                 }
 
                 s->block_last_index[i] = ret;
             }

         }
     } 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->picture_structure == PICT_FRAME
                     && !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 = mpeg_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->picture_structure == PICT_FRAME && 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 = mpeg_get_qscale(s);

 
             /* motion vectors */
             s->mv_dir = (mb_type >> 13) & 3;

             ff_tlog(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] *= 2;
                                 s->mv[i][0][1] *= 2;

                             }
                         }
                     }
                 } 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;

                                 ff_tlog(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] = 2 * val;

                                 s->mv[i][j][1]      = val;

                                 ff_tlog(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 AVERROR_INVALIDDATA;

                 }

                 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 * (1 << my_shift);
                         s->last_mv[i][1][1] = my * (1 << 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 AVERROR_INVALIDDATA;

             }
         }
 
         s->mb_intra = 0;
         if (HAS_CBP(mb_type)) {

             s->bdsp.clear_blocks(s->block[0]);

 
             cbp = get_vlc2(&s->gb, ff_mb_pat_vlc.table, MB_PAT_VLC_BITS, 1);
             if (mb_block_count > 6) {

                 cbp *= 1 << mb_block_count - 6;

                 cbp  |= get_bits(&s->gb, mb_block_count - 6);

                 s->bdsp.clear_blocks(s->block[6]);

             }
             if (cbp <= 0) {

                 av_log(s->avctx, AV_LOG_ERROR,

                        "invalid cbp %d at %d %d\n", cbp, s->mb_x, s->mb_y);

                 return AVERROR_INVALIDDATA;

             }
 

             // if 1, we memcpy blocks in xvmcvideo

             if ((CONFIG_MPEG1_XVMC_HWACCEL || CONFIG_MPEG2_XVMC_HWACCEL) && s->pack_pblocks)

                 ff_xvmc_pack_pblocks(s, cbp);
 
             if (s->codec_id == AV_CODEC_ID_MPEG2VIDEO) {

                 if (s->avctx->flags2 & AV_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 ((ret = mpeg2_decode_block_non_intra(s, *s->pblocks[i], i)) < 0)
                                 return ret;

                         } else {
                             s->block_last_index[i] = -1;
                         }
                         cbp += cbp;
                     }
                 }
             } else {

                 if (s->avctx->flags2 & AV_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 ((ret = mpeg1_decode_block_inter(s, *s->pblocks[i], i)) < 0)
                                 return ret;

                         } 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.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;
 

     ff_mpv_decode_defaults(s2);

 
     if (   avctx->codec_tag != AV_RL32("VCR2")
         && avctx->codec_tag != AV_RL32("BW10"))
         avctx->coded_width = avctx->coded_height = 0; // do not trust dimensions from input

     ff_mpv_decode_init(s2, avctx);

 
     s->mpeg_enc_ctx.avctx  = avctx;

 
     /* we need some permutation to store matrices,
      * until the decoder sets the real permutation. */
     ff_mpv_idct_init(s2);

     ff_mpeg12_common_init(&s->mpeg_enc_ctx);
     ff_mpeg12_init_vlcs();
 

     s2->chroma_format              = 1;

     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;

     return 0;
 }
 

 #if HAVE_THREADS

 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;
 }

 #endif

 
 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 AVPixelFormat mpeg1_hwaccel_pixfmt_list_420[] = {

 #if CONFIG_MPEG1_NVDEC_HWACCEL
     AV_PIX_FMT_CUDA,
 #endif

 #if CONFIG_MPEG1_XVMC_HWACCEL
     AV_PIX_FMT_XVMC,

 #endif

 #if CONFIG_MPEG1_VDPAU_HWACCEL

     AV_PIX_FMT_VDPAU,

 #endif
     AV_PIX_FMT_YUV420P,
     AV_PIX_FMT_NONE
 };

 static const enum AVPixelFormat mpeg2_hwaccel_pixfmt_list_420[] = {

 #if CONFIG_MPEG2_NVDEC_HWACCEL
     AV_PIX_FMT_CUDA,
 #endif

 #if CONFIG_MPEG2_XVMC_HWACCEL
     AV_PIX_FMT_XVMC,

 #endif

 #if CONFIG_MPEG2_VDPAU_HWACCEL

     AV_PIX_FMT_VDPAU,

 #endif

 #if CONFIG_MPEG2_DXVA2_HWACCEL
     AV_PIX_FMT_DXVA2_VLD,
 #endif

 #if CONFIG_MPEG2_D3D11VA_HWACCEL
     AV_PIX_FMT_D3D11VA_VLD,

     AV_PIX_FMT_D3D11,

 #endif

 #if CONFIG_MPEG2_VAAPI_HWACCEL

     AV_PIX_FMT_VAAPI,

 #endif

 #if CONFIG_MPEG2_VIDEOTOOLBOX_HWACCEL
     AV_PIX_FMT_VIDEOTOOLBOX,
 #endif

     AV_PIX_FMT_YUV420P,
     AV_PIX_FMT_NONE
 };
 

 static const enum AVPixelFormat mpeg12_pixfmt_list_422[] = {
     AV_PIX_FMT_YUV422P,
     AV_PIX_FMT_NONE
 };
 
 static const enum AVPixelFormat mpeg12_pixfmt_list_444[] = {
     AV_PIX_FMT_YUV444P,
     AV_PIX_FMT_NONE
 };
 

 static enum AVPixelFormat mpeg_get_pixelformat(AVCodecContext *avctx)
 {

     Mpeg1Context *s1  = avctx->priv_data;

     MpegEncContext *s = &s1->mpeg_enc_ctx;

     const enum AVPixelFormat *pix_fmts;

     if (CONFIG_GRAY && (avctx->flags & AV_CODEC_FLAG_GRAY))

         return AV_PIX_FMT_GRAY8;
 

     if (s->chroma_format < 2)

         pix_fmts = avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO ?

                                 mpeg1_hwaccel_pixfmt_list_420 :

                                 mpeg2_hwaccel_pixfmt_list_420;

     else if (s->chroma_format == 2)

         pix_fmts = mpeg12_pixfmt_list_422;

     else

         pix_fmts = mpeg12_pixfmt_list_444;
 

     return ff_thread_get_format(avctx, pix_fmts);

 }
 
 static void setup_hwaccel_for_pixfmt(AVCodecContext *avctx)
 {
     // until then pix_fmt may be changed right after codec init

     if (avctx->hwaccel)

         if (avctx->idct_algo == FF_IDCT_AUTO)

             avctx->idct_algo = FF_IDCT_NONE;

 
     if (avctx->hwaccel && avctx->pix_fmt == AV_PIX_FMT_XVMC) {
         Mpeg1Context *s1 = avctx->priv_data;
         MpegEncContext *s = &s1->mpeg_enc_ctx;
 
         s->pack_pblocks = 1;
     }

 }
 
 /* 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];

     int ret;

     if (avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
         // MPEG-1 aspect

         AVRational aspect_inv = av_d2q(ff_mpeg1_aspect[s->aspect_ratio_info], 255);
         avctx->sample_aspect_ratio = (AVRational) { aspect_inv.den, aspect_inv.num };

     } else { // MPEG-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});

                 ff_dlog(avctx, "aspect A %d/%d\n",

                         ff_mpeg2_aspect[s->aspect_ratio_info].num,
                         ff_mpeg2_aspect[s->aspect_ratio_info].den);

                 ff_dlog(avctx, "aspect 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
 

     if (av_image_check_sar(s->width, s->height,
                            avctx->sample_aspect_ratio) < 0) {
         av_log(avctx, AV_LOG_WARNING, "ignoring invalid SAR: %u/%u\n",
                 avctx->sample_aspect_ratio.num,
                 avctx->sample_aspect_ratio.den);
         avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
     }

     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               ||

         av_cmp_q(s1->save_aspect, s->avctx->sample_aspect_ratio) ||

         (s1->save_progressive_seq != s->progressive_sequence && FFALIGN(s->height, 16) != FFALIGN(s->height, 32)) ||

         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;

             s1->mpeg_enc_ctx_allocated = 0;

         }
 

         ret = ff_set_dimensions(avctx, s->width, s->height);
         if (ret < 0)
             return ret;
 

         if (avctx->codec_id == AV_CODEC_ID_MPEG2VIDEO && s->bit_rate) {
             avctx->rc_max_rate = s->bit_rate;
         } else if (avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO && s->bit_rate &&
                    (s->bit_rate != 0x3FFFF*400 || s->vbv_delay != 0xFFFF)) {
             avctx->bit_rate = s->bit_rate;
         }

         s1->save_aspect          = s->avctx->sample_aspect_ratio;

         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->framerate = ff_mpeg12_frame_rate_tab[s->frame_rate_index];

             avctx->ticks_per_frame     = 1;

 
             avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;

         } else { // MPEG-2
             // MPEG-2 fps

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

                       ff_mpeg12_frame_rate_tab[s->frame_rate_index].num * s1->frame_rate_ext.num,

                       ff_mpeg12_frame_rate_tab[s->frame_rate_index].den * s1->frame_rate_ext.den,
                       1 << 30);
             avctx->ticks_per_frame = 2;

 
             switch (s->chroma_format) {
             case 1: avctx->chroma_sample_location = AVCHROMA_LOC_LEFT; break;
             case 2:
             case 3: avctx->chroma_sample_location = AVCHROMA_LOC_TOPLEFT; break;

             default: av_assert0(0);

             }

         } // MPEG-2
 
         avctx->pix_fmt = mpeg_get_pixelformat(avctx);

         setup_hwaccel_for_pixfmt(avctx);

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

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

         ff_mpv_idct_init(s);

         if ((ret = ff_mpv_common_init(s)) < 0)
             return ret;

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

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

     s->vbv_delay = vbv_delay;

     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 AVERROR_INVALIDDATA;

         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 AVERROR_INVALIDDATA;

         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 */

 
     if (!s->chroma_format) {
         s->chroma_format = 1;
         av_log(s->avctx, AV_LOG_WARNING, "Chroma format invalid\n");
     }
 

     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) * 400LL;

     check_marker(s->avctx, &s->gb, "after bit rate extension");

     s->avctx->rc_buffer_size += get_bits(&s->gb, 8) * 1024 * 16 << 10;
 
     s->low_delay = get_bits1(&s->gb);

     if (s->avctx->flags & AV_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;
 

     ff_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 ps: %d cf:%d vbv buffer: %d, bitrate:%"PRId64"\n",

                s->avctx->profile, s->avctx->level, s->progressive_sequence, s->chroma_format,

                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 (%"PRId16",%"PRId16") (%"PRId16",%"PRId16") (%"PRId16",%"PRId16")\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->idsp.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 AVERROR_INVALIDDATA;

         }
         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)
 {

     ff_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->idsp.idct_permutation, &s->inter_scantable, ff_alternate_vertical_scan);
         ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable, ff_alternate_vertical_scan);

     } else {

         ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable, ff_zigzag_direct);
         ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct);

     }
 
     /* composite display not parsed */

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

     int ret;

 
     /* start frame decoding */
     if (s->first_field || s->picture_structure == PICT_FRAME) {
         AVFrameSideData *pan_scan;
 

         if ((ret = ff_mpv_frame_start(s, avctx)) < 0)
             return ret;

 
         ff_mpeg_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;

             }
         }
 

         pan_scan = av_frame_new_side_data(s->current_picture_ptr->f,

                                           AV_FRAME_DATA_PANSCAN,
                                           sizeof(s1->pan_scan));
         if (!pan_scan)
             return AVERROR(ENOMEM);
         memcpy(pan_scan->data, &s1->pan_scan, sizeof(s1->pan_scan));
 

         if (s1->a53_caption) {
             AVFrameSideData *sd = av_frame_new_side_data(

                 s->current_picture_ptr->f, AV_FRAME_DATA_A53_CC,

                 s1->a53_caption_size);
             if (sd)
                 memcpy(sd->data, s1->a53_caption, s1->a53_caption_size);
             av_freep(&s1->a53_caption);
         }

 
         if (s1->has_stereo3d) {

             AVStereo3D *stereo = av_stereo3d_create_side_data(s->current_picture_ptr->f);

             if (!stereo)
                 return AVERROR(ENOMEM);
 
             *stereo = s1->stereo3d;
             s1->has_stereo3d = 0;
         }

 
         if (s1->has_afd) {

             AVFrameSideData *sd =
                 av_frame_new_side_data(s->current_picture_ptr->f,
                                        AV_FRAME_DATA_AFD, 1);

             if (!sd)
                 return AVERROR(ENOMEM);
 

             *sd->data   = s1->afd;

             s1->has_afd = 0;
         }
 

         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 AVERROR_INVALIDDATA;

         }
 
         if (s->avctx->hwaccel &&
             (s->avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD)) {

             if ((ret = s->avctx->hwaccel->end_frame(s->avctx)) < 0) {

                 av_log(avctx, AV_LOG_ERROR,
                        "hardware accelerator failed to decode first field\n");

                 return ret;
             }

         }
 
         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 ((ret = avctx->hwaccel->start_frame(avctx, buf, buf_size)) < 0)
             return ret;

     }
 
     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;

     int ret;

 
     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 = mpeg_get_qscale(s);

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

         return AVERROR_INVALIDDATA;

     }
 
     /* extra slice info */

     if (skip_1stop_8data_bits(&s->gb) < 0)
         return AVERROR_INVALIDDATA;

 
     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, ff_mbincr_vlc.table,
                                 MBINCR_VLC_BITS, 2);
             if (code < 0) {
                 av_log(s->avctx, AV_LOG_ERROR, "first mb_incr damaged\n");

                 return AVERROR_INVALIDDATA;

             }
             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 AVERROR_INVALIDDATA;

     }
 

     if (avctx->hwaccel && avctx->hwaccel->decode_slice) {

         const uint8_t *buf_end, *buf_start = *buf - 4; /* include start_code */
         int start_code = -1;
         buf_end = avpriv_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_MPEG1_XVMC_HWACCEL || CONFIG_MPEG2_XVMC_HWACCEL) && s->pack_pblocks)

             ff_xvmc_init_block(s); // set s->block
 

         if ((ret = mpeg_decode_mb(s, s->block)) < 0)
             return ret;

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

             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.motion_val[dir][xy][0]     = motion_x;
                     s->current_picture.motion_val[dir][xy][1]     = motion_y;

                     s->current_picture.motion_val[dir][xy + 1][0] = motion_x;
                     s->current_picture.motion_val[dir][xy + 1][1] = motion_y;

                     s->current_picture.ref_index [dir][b8_xy]     =

                     s->current_picture.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_reconstruct_mb(s, s->block);

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

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

             int left;

             ff_mpeg_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 >= 32 && !is_d10) {
                     GetBitContext gb = s->gb;
                     align_get_bits(&gb);
                     if (show_bits(&gb, 24) == 0x060E2B) {
                         av_log(avctx, AV_LOG_DEBUG, "Invalid MXF data found in video stream\n");
                         is_d10 = 1;
                     }

                     if (left > 32 && show_bits_long(&gb, 32) == 0x201) {
                         av_log(avctx, AV_LOG_DEBUG, "skipping m704 alpha (unsupported)\n");
                         goto eos;
                     }

                 }
 

                 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 at %d %d\n",
                            left, left>0 ? show_bits(&s->gb, FFMIN(left, 23)) : 0, s->mb_x, s->mb_y);

                     return AVERROR_INVALIDDATA;

                 } else
                     goto eos;
             }

             // There are some files out there which are missing the last slice

             // in cases where the slice is completely outside the visible

             // area, we detect this here instead of running into the end expecting
             // more data

             left = get_bits_left(&s->gb);

             if (s->mb_y >= ((s->height + 15) >> 4) &&
                 !s->progressive_sequence &&

                 left <= 25 &&
                 left >= 0 &&

                 s->mb_skip_run == -1 &&

                 (!left || show_bits(&s->gb, left) == 0))

                 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, ff_mbincr_vlc.table,
                                     MBINCR_VLC_BITS, 2);
                 if (code < 0) {
                     av_log(s->avctx, AV_LOG_ERROR, "mb incr damaged\n");

                     return AVERROR_INVALIDDATA;

                 }
                 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 AVERROR_INVALIDDATA;

                         }
                         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 AVERROR_INVALIDDATA;

                 }
 
                 /* 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];

                     s->field_select[0][0] = (s->picture_structure - 1) & 1;
                     s->field_select[1][0] = (s->picture_structure - 1) & 1;

                 }
             }
         }
     }
 eos: // end of slice

     if (get_bits_left(&s->gb) < 0) {
         av_log(s, AV_LOG_ERROR, "overread %d\n", -get_bits_left(&s->gb));

         return AVERROR_INVALIDDATA;

     }

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

     ff_dlog(s, "Slice start:%d %d  end:%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->er.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();

         ff_dlog(c, "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->er.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->er, 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->er, 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_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 AVERROR_INVALIDDATA;

     }
 }
 
 /**
  * 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) {

         int ret = s->avctx->hwaccel->end_frame(s->avctx);
         if (ret < 0) {

             av_log(avctx, AV_LOG_ERROR,
                    "hardware accelerator failed to decode picture\n");

             return ret;
         }

     }
 
     /* end of slice reached */

     if (/* s->mb_y << field_pic == s->mb_height && */ !s->first_field && !s1->first_slice) {

         /* end of image */
 
         ff_er_frame_end(&s->er);
 

         ff_mpv_frame_end(s);

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

             int ret = av_frame_ref(pict, s->current_picture_ptr->f);

             if (ret < 0)
                 return ret;

             ff_print_debug_info(s, s->current_picture_ptr, pict);
             ff_mpv_export_qp_table(s, pict, s->current_picture_ptr, FF_QSCALE_TYPE_MPEG2);

         } 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) {

                 int ret = av_frame_ref(pict, s->last_picture_ptr->f);

                 if (ret < 0)
                     return ret;

                 ff_print_debug_info(s, s->last_picture_ptr, pict);
                 ff_mpv_export_qp_table(s, pict, s->last_picture_ptr, FF_QSCALE_TYPE_MPEG2);

             }
         }
 
         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) {

         av_log(avctx, AV_LOG_WARNING,
                "Invalid horizontal or vertical size value.\n");

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

             return AVERROR_INVALIDDATA;
     }
     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 AVERROR_INVALIDDATA;

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

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

         av_log(avctx, AV_LOG_WARNING,
                "frame_rate_index %d is invalid\n", s->frame_rate_index);

         s->frame_rate_index = 1;

     }

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

     if (check_marker(s->avctx, &s->gb, "in sequence header") == 0) {

         return AVERROR_INVALIDDATA;

     }

 
     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->idsp.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->idsp.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 AVERROR_INVALIDDATA;

     }
 

     s->width  = width;
     s->height = height;
 

     /* 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->avctx->flags & AV_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:%"PRId64", aspect_ratio_info: %d \n",

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

 
     return 0;
 }
 
 static int vcr2_init_sequence(AVCodecContext *avctx)
 {

     Mpeg1Context *s1  = avctx->priv_data;

     MpegEncContext *s = &s1->mpeg_enc_ctx;

     int i, v, ret;

 
     /* start new MPEG-1 context decoding */
     s->out_format = FMT_MPEG1;
     if (s1->mpeg_enc_ctx_allocated) {

         ff_mpv_common_end(s);

         s1->mpeg_enc_ctx_allocated = 0;

     }

     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);

     setup_hwaccel_for_pixfmt(avctx);

     ff_mpv_idct_init(s);

     if ((ret = ff_mpv_common_init(s)) < 0)
         return ret;

     s1->mpeg_enc_ctx_allocated = 1;
 
     for (i = 0; i < 64; i++) {

         int j = s->idsp.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 {
         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 int mpeg_decode_a53_cc(AVCodecContext *avctx,
                               const uint8_t *p, int buf_size)
 {
     Mpeg1Context *s1 = avctx->priv_data;
 
     if (buf_size >= 6 &&
         p[0] == 'G' && p[1] == 'A' && p[2] == '9' && p[3] == '4' &&
         p[4] == 3 && (p[5] & 0x40)) {
         /* extract A53 Part 4 CC data */
         int cc_count = p[5] & 0x1f;
         if (cc_count > 0 && buf_size >= 7 + cc_count * 3) {
             av_freep(&s1->a53_caption);
             s1->a53_caption_size = cc_count * 3;

             s1->a53_caption      = av_malloc(s1->a53_caption_size);

             if (!s1->a53_caption) {
                 s1->a53_caption_size = 0;
             } else {

                 memcpy(s1->a53_caption, p + 7, s1->a53_caption_size);

             }

             avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;

         }
         return 1;

     } else if (buf_size >= 2 &&
                p[0] == 0x03 && (p[1]&0x7f) == 0x01) {
         /* extract SCTE-20 CC data */
         GetBitContext gb;
         int cc_count = 0;
         int i;
 
         init_get_bits(&gb, p + 2, buf_size - 2);
         cc_count = get_bits(&gb, 5);
         if (cc_count > 0) {
             av_freep(&s1->a53_caption);
             s1->a53_caption_size = cc_count * 3;
             s1->a53_caption      = av_mallocz(s1->a53_caption_size);

             if (!s1->a53_caption) {
                 s1->a53_caption_size = 0;
             } else {

                 uint8_t field, cc1, cc2;
                 uint8_t *cap = s1->a53_caption;
                 for (i = 0; i < cc_count && get_bits_left(&gb) >= 26; i++) {
                     skip_bits(&gb, 2); // priority
                     field = get_bits(&gb, 2);
                     skip_bits(&gb, 5); // line_offset
                     cc1 = get_bits(&gb, 8);
                     cc2 = get_bits(&gb, 8);
                     skip_bits(&gb, 1); // marker
 
                     if (!field) { // forbidden
                         cap[0] = cap[1] = cap[2] = 0x00;
                     } else {
                         field = (field == 2 ? 1 : 0);
                         if (!s1->mpeg_enc_ctx.top_field_first) field = !field;
                         cap[0] = 0x04 | field;
                         cap[1] = ff_reverse[cc1];
                         cap[2] = ff_reverse[cc2];
                     }
                     cap += 3;
                 }
             }
             avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
         }
         return 1;

     } else if (buf_size >= 11 &&

                p[0] == 'C' && p[1] == 'C' && p[2] == 0x01 && p[3] == 0xf8) {

         /* extract DVD CC data
          *
          * uint32_t   user_data_start_code        0x000001B2    (big endian)
          * uint16_t   user_identifier             0x4343 "CC"
          * uint8_t    user_data_type_code         0x01
          * uint8_t    caption_block_size          0xF8
          * uint8_t
          *   bit 7    caption_odd_field_first     1=odd field (CC1/CC2) first  0=even field (CC3/CC4) first
          *   bit 6    caption_filler              0
          *   bit 5:1  caption_block_count         number of caption blocks (pairs of caption words = frames). Most DVDs use 15 per start of GOP.
          *   bit 0    caption_extra_field_added   1=one additional caption word
          *
          * struct caption_field_block {
          *   uint8_t
          *     bit 7:1 caption_filler             0x7F (all 1s)
          *     bit 0   caption_field_odd          1=odd field (this is CC1/CC2)  0=even field (this is CC3/CC4)
          *   uint8_t   caption_first_byte
          *   uint8_t   caption_second_byte
          * } caption_block[(caption_block_count * 2) + caption_extra_field_added];
          *
          * Some DVDs encode caption data for both fields with caption_field_odd=1. The only way to decode the fields
          * correctly is to start on the field indicated by caption_odd_field_first and count between odd/even fields.
          * Don't assume that the first caption word is the odd field. There do exist MPEG files in the wild that start
          * on the even field. There also exist DVDs in the wild that encode an odd field count and the
          * caption_extra_field_added/caption_odd_field_first bits change per packet to allow that. */

         int cc_count = 0;
         int i;
         // There is a caption count field in the data, but it is often

         // incorrect.  So count the number of captions present.

         for (i = 5; i + 6 <= buf_size && ((p[i] & 0xfe) == 0xfe); i += 6)
             cc_count++;
         // Transform the DVD format into A53 Part 4 format
         if (cc_count > 0) {
             av_freep(&s1->a53_caption);
             s1->a53_caption_size = cc_count * 6;

             s1->a53_caption      = av_malloc(s1->a53_caption_size);

             if (!s1->a53_caption) {
                 s1->a53_caption_size = 0;
             } else {

                 uint8_t field1 = !!(p[4] & 0x80);
                 uint8_t *cap = s1->a53_caption;
                 p += 5;
                 for (i = 0; i < cc_count; i++) {
                     cap[0] = (p[0] == 0xff && field1) ? 0xfc : 0xfd;
                     cap[1] = p[1];
                     cap[2] = p[2];
                     cap[3] = (p[3] == 0xff && !field1) ? 0xfc : 0xfd;
                     cap[4] = p[4];
                     cap[5] = p[5];
                     cap += 6;
                     p += 6;
                 }
             }

             avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;

         }
         return 1;
     }
     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;

     Mpeg1Context *s1 = avctx->priv_data;

 #if 0
     int i;
     for(i=0; !(!p[i-2] && !p[i-1] && p[i]==1) && i<buf_size; i++){
         av_log(avctx, AV_LOG_ERROR, "%c", p[i]);
     }
     av_log(avctx, AV_LOG_ERROR, "\n");
 #endif
 

     if (buf_size > 29){

         int i;
         for(i=0; i<20; i++)

             if (!memcmp(p+i, "\0TMPGEXS\0", 9)){

                 s->tmpgexs= 1;
             }
     }

     /* 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;

             s1->has_afd = 1;

             s1->afd     = p[0] & 0x0f;

         }

     } else if (buf_end - p >= 6 &&
                p[0] == 'J' && p[1] == 'P' && p[2] == '3' && p[3] == 'D' &&
                p[4] == 0x03) { // S3D_video_format_length
         // the 0x7F mask ignores the reserved_bit value
         const uint8_t S3D_video_format_type = p[5] & 0x7F;
 
         if (S3D_video_format_type == 0x03 ||
             S3D_video_format_type == 0x04 ||
             S3D_video_format_type == 0x08 ||
             S3D_video_format_type == 0x23) {

             s1->has_stereo3d = 1;

 
             switch (S3D_video_format_type) {
             case 0x03:

                 s1->stereo3d.type = AV_STEREO3D_SIDEBYSIDE;

                 break;
             case 0x04:

                 s1->stereo3d.type = AV_STEREO3D_TOPBOTTOM;

                 break;
             case 0x08:

                 s1->stereo3d.type = AV_STEREO3D_2D;

                 break;
             case 0x23:

                 s1->stereo3d.type = AV_STEREO3D_SIDEBYSIDE_QUINCUNX;

                 break;
             }
         }

     } else if (mpeg_decode_a53_cc(avctx, p, buf_size)) {
         return;

     }
 }
 
 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 = s-> timecode_frame_start = get_bits(&s->gb, 25);
 
 #if FF_API_PRIVATE_OPT
 FF_DISABLE_DEPRECATION_WARNINGS
     avctx->timecode_frame_start = tc;
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif

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

     /* broken_link indicates 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);
     }

 }
 

 static int decode_chunks(AVCodecContext *avctx, AVFrame *picture,
                          int *got_output, 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, skip_frame = 0;

     int picture_start_code_seen = 0;

 
     for (;;) {
         /* find next start code */
         uint32_t start_code = -1;
         buf_ptr = avpriv_find_start_code(buf_ptr, buf_end, &start_code);
         if (start_code > 0x1ff) {

             if (!skip_frame) {

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

                     !avctx->hwaccel) {

                     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->er.error_count += s2->thread_context[i]->er.error_count;
                 }
 
                 ret = slice_end(avctx, picture);
                 if (ret < 0)
                     return ret;
                 else if (ret) {

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

                         *got_output = 1;
                 }
             }
             s2->pict_type = 0;

 
             if (avctx->err_recognition & AV_EF_EXPLODE && s2->er.error_count)
                 return AVERROR_INVALIDDATA;
 

             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, "%3"PRIX32" at %"PTRDIFF_SPECIFIER" 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 (picture_start_code_seen && s2->picture_structure == PICT_FRAME) {
                /* If it's a frame picture, there can't be more than one picture header.
                   Yet, it does happen and we need to handle it. */
                av_log(avctx, AV_LOG_WARNING, "ignoring extra picture following a frame-picture\n");
                break;
             }
             picture_start_code_seen = 1;
 

             if (s2->width <= 0 || s2->height <= 0) {
                 av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d.\n",
                        s2->width, s2->height);
                 return AVERROR_INVALIDDATA;
             }
 

             if (s->tmpgexs){

                 s2->intra_dc_precision= 3;
                 s2->intra_matrix[0]= 1;
             }

             if (HAVE_THREADS && (avctx->active_thread_type & FF_THREAD_SLICE) &&
                 !avctx->hwaccel && 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->er.error_count += s2->thread_context[i]->er.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;

                 s->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 (buf_end - buf_ptr < 2) {
                     av_log(s2->avctx, AV_LOG_ERROR, "slice too small\n");
                     return AVERROR_INVALIDDATA;
                 }
 

                 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 AVERROR_INVALIDDATA;

                 }
 

                 if (!s2->last_picture_ptr) {

                     /* 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) {

                             skip_frame = 1;

                             av_log(s2->avctx, AV_LOG_DEBUG,
                                    "Skipping B slice due to open GOP\n");

                             break;

                         }

                     }
                 }

                 if (s2->pict_type == AV_PICTURE_TYPE_I || (s2->avctx->flags2 & AV_CODEC_FLAG2_SHOW_ALL))

                     s->sync = 1;

                 if (!s2->next_picture_ptr) {

                     /* 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) {
                         skip_frame = 1;

                         av_log(s2->avctx, AV_LOG_DEBUG,
                                "Skipping P slice due to !sync\n");

                         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) {

                     skip_frame = 1;

                     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 (s->first_slice) {

                     skip_frame     = 0;

                     s->first_slice = 0;

                     if ((ret = mpeg_field_start(s2, buf, buf_size)) < 0)
                         return ret;

                 }
                 if (!s2->current_picture_ptr) {

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

                     return AVERROR_INVALIDDATA;
                 }
 

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

                     !avctx->hwaccel) {

                     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;
                             ret = ff_update_duplicate_context(thread_context, s2);

                             if (ret < 0)
                                 return ret;
                         }

                         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->er, 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->er, 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 int mpeg_decode_frame(AVCodecContext *avctx, void *data,
                              int *got_output, AVPacket *avpkt)

 {
     const uint8_t *buf = avpkt->data;

     int ret;

     int buf_size = avpkt->size;
     Mpeg1Context *s = avctx->priv_data;
     AVFrame *picture = data;
     MpegEncContext *s2 = &s->mpeg_enc_ctx;
 
     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) {

             int ret = av_frame_ref(picture, s2->next_picture_ptr->f);

             if (ret < 0)
                 return ret;
 
             s2->next_picture_ptr = NULL;
 
             *got_output = 1;
         }
         return buf_size;
     }
 

     if (s2->avctx->flags & AV_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->extradata_decoded) {

         ret = decode_chunks(avctx, picture, got_output,
                             avctx->extradata, avctx->extradata_size);
         if (*got_output) {

             av_log(avctx, AV_LOG_ERROR, "picture in extradata\n");

             av_frame_unref(picture);

             *got_output = 0;
         }

         s->extradata_decoded = 1;

         if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE)) {
             s2->current_picture_ptr = NULL;

             return ret;

         }

     }
 

     ret = decode_chunks(avctx, picture, got_output, buf, buf_size);

     if (ret<0 || *got_output) {

         s2->current_picture_ptr = NULL;
 

         if (s2->timecode_frame_start != -1 && *got_output) {
             AVFrameSideData *tcside = av_frame_new_side_data(picture,
                                                              AV_FRAME_DATA_GOP_TIMECODE,
                                                              sizeof(int64_t));
             if (!tcside)
                 return AVERROR(ENOMEM);
             memcpy(tcside->data, &s2->timecode_frame_start, sizeof(int64_t));
 
             s2->timecode_frame_start = -1;
         }
     }
 

     return ret;

 }
 
 static void flush(AVCodecContext *avctx)
 {
     Mpeg1Context *s = avctx->priv_data;
 

     s->sync       = 0;

 
     ff_mpeg_flush(avctx);
 }
 

 static av_cold 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);

     av_freep(&s->a53_caption);

     return 0;
 }
 
 AVCodec ff_mpeg1video_decoder = {
     .name                  = "mpeg1video",

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

     .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          = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1 |
                              AV_CODEC_CAP_TRUNCATED | AV_CODEC_CAP_DELAY |
                              AV_CODEC_CAP_SLICE_THREADS,

     .caps_internal         = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,

     .flush                 = flush,

     .max_lowres            = 3,

     .update_thread_context = ONLY_IF_THREADS_ENABLED(mpeg_decode_update_thread_context),
     .hw_configs            = (const AVCodecHWConfigInternal*[]) {

 #if CONFIG_MPEG1_NVDEC_HWACCEL

                                HWACCEL_NVDEC(mpeg1),
 #endif
 #if CONFIG_MPEG1_VDPAU_HWACCEL
                                HWACCEL_VDPAU(mpeg1),
 #endif
 #if CONFIG_MPEG1_VIDEOTOOLBOX_HWACCEL
                                HWACCEL_VIDEOTOOLBOX(mpeg1),
 #endif
 #if CONFIG_MPEG1_XVMC_HWACCEL
                                HWACCEL_XVMC(mpeg1),
 #endif
                                NULL
                            },

 };
 
 AVCodec ff_mpeg2video_decoder = {
     .name           = "mpeg2video",

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

     .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   = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1 |
                       AV_CODEC_CAP_TRUNCATED | AV_CODEC_CAP_DELAY |
                       AV_CODEC_CAP_SLICE_THREADS,

     .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,

     .flush          = flush,

     .max_lowres     = 3,

     .profiles       = NULL_IF_CONFIG_SMALL(ff_mpeg2_video_profiles),

     .hw_configs     = (const AVCodecHWConfigInternal*[]) {
 #if CONFIG_MPEG2_DXVA2_HWACCEL
                         HWACCEL_DXVA2(mpeg2),
 #endif
 #if CONFIG_MPEG2_D3D11VA_HWACCEL
                         HWACCEL_D3D11VA(mpeg2),
 #endif
 #if CONFIG_MPEG2_D3D11VA2_HWACCEL
                         HWACCEL_D3D11VA2(mpeg2),
 #endif
 #if CONFIG_MPEG2_NVDEC_HWACCEL
                         HWACCEL_NVDEC(mpeg2),
 #endif
 #if CONFIG_MPEG2_VAAPI_HWACCEL
                         HWACCEL_VAAPI(mpeg2),
 #endif
 #if CONFIG_MPEG2_VDPAU_HWACCEL
                         HWACCEL_VDPAU(mpeg2),
 #endif
 #if CONFIG_MPEG2_VIDEOTOOLBOX_HWACCEL
                         HWACCEL_VIDEOTOOLBOX(mpeg2),
 #endif
 #if CONFIG_MPEG2_XVMC_HWACCEL
                         HWACCEL_XVMC(mpeg2),
 #endif
                         NULL
                     },

 };
 

 //legacy decoder
 AVCodec ff_mpegvideo_decoder = {
     .name           = "mpegvideo",

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

     .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   = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_TRUNCATED | AV_CODEC_CAP_DELAY | AV_CODEC_CAP_SLICE_THREADS,

     .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,

     .flush          = flush,
     .max_lowres     = 3,
 };