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   1 /*
   2  * MPEG1 codec / MPEG2 decoder
   3  * Copyright (c) 2000,2001 Fabrice Bellard.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 /**
  21  * @file mpeg12.c
  22  * MPEG1 codec / MPEG2 decoder.
  23  */
  24
  25 //#define DEBUG
  26 #include "avcodec.h"
  27 #include "dsputil.h"
  28 #include "mpegvideo.h"
  29
  30 #include "mpeg12data.h"
  31
  32
  33 /* Start codes. */
  34 #define SEQ_END_CODE            0x000001b7
  35 #define SEQ_START_CODE          0x000001b3
  36 #define GOP_START_CODE          0x000001b8
  37 #define PICTURE_START_CODE      0x00000100
  38 #define SLICE_MIN_START_CODE    0x00000101
  39 #define SLICE_MAX_START_CODE    0x000001af
  40 #define EXT_START_CODE          0x000001b5
  41 #define USER_START_CODE         0x000001b2
  42
  43 #define DC_VLC_BITS 9
  44 #define MV_VLC_BITS 9
  45 #define MBINCR_VLC_BITS 9
  46 #define MB_PAT_VLC_BITS 9
  47 #define MB_PTYPE_VLC_BITS 6
  48 #define MB_BTYPE_VLC_BITS 6
  49 #define TEX_VLC_BITS 9
  50
  51 static void mpeg1_encode_block(MpegEncContext *s,
  52                          DCTELEM *block,
  53                          int component);
  54 static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code);    // RAL: f_code parameter added
  55 static void mpeg1_skip_picture(MpegEncContext *s, int pict_num);
  56 static inline int mpeg1_decode_block_inter(MpegEncContext *s,
  57                               DCTELEM *block,
  58                               int n);
  59 static inline int mpeg1_decode_block_intra(MpegEncContext *s,
  60                               DCTELEM *block,
  61                               int n);
  62 static inline int mpeg2_decode_block_non_intra(MpegEncContext *s,
  63                                         DCTELEM *block,
  64                                         int n);
  65 static inline int mpeg2_decode_block_intra(MpegEncContext *s,
  66                                     DCTELEM *block,
  67                                     int n);
  68 static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);
  69
  70 #ifdef CONFIG_ENCODERS
  71 static uint8_t (*mv_penalty)[MAX_MV*2+1]= NULL;
  72 static uint8_t fcode_tab[MAX_MV*2+1];
  73
  74 static uint32_t uni_mpeg1_ac_vlc_bits[64*64*2];
  75 static uint8_t  uni_mpeg1_ac_vlc_len [64*64*2];
  76
  77 /* simple include everything table for dc, first byte is bits number next 3 are code*/
  78 static uint32_t mpeg1_lum_dc_uni[512];
  79 static uint32_t mpeg1_chr_dc_uni[512];
  80
  81 static uint8_t mpeg1_index_run[2][64];
  82 static int8_t mpeg1_max_level[2][64];
  83 #endif
  84
  85 static void init_2d_vlc_rl(RLTable *rl)
  86 {
  87     int i;
  88
  89     init_vlc(&rl->vlc, TEX_VLC_BITS, rl->n + 2,
  90              &rl->table_vlc[0][1], 4, 2,
  91              &rl->table_vlc[0][0], 4, 2);
  92
  93
  94     rl->rl_vlc[0]= av_malloc(rl->vlc.table_size*sizeof(RL_VLC_ELEM));
  95     for(i=0; i<rl->vlc.table_size; i++){
  96         int code= rl->vlc.table[i][0];
  97         int len = rl->vlc.table[i][1];
  98         int level, run;
  99
 100         if(len==0){ // illegal code
 101             run= 65;
 102             level= MAX_LEVEL;
 103         }else if(len<0){ //more bits needed
 104             run= 0;
 105             level= code;
 106         }else{
 107             if(code==rl->n){ //esc
 108                 run= 65;
 109                 level= 0;
 110             }else if(code==rl->n+1){ //eob
 111                 run= 0;
 112                 level= 127;
 113             }else{
 114                 run=   rl->table_run  [code] + 1;
 115                 level= rl->table_level[code];
 116             }
 117         }
 118         rl->rl_vlc[0][i].len= len;
 119         rl->rl_vlc[0][i].level= level;
 120         rl->rl_vlc[0][i].run= run;
 121     }
 122 }
 123
 124 #ifdef CONFIG_ENCODERS
 125 static void init_uni_ac_vlc(RLTable *rl, uint32_t *uni_ac_vlc_bits, uint8_t *uni_ac_vlc_len){
 126     int i;
 127
 128     for(i=0; i<128; i++){
 129         int level= i-64;
 130         int run;
 131         for(run=0; run<64; run++){
 132             int len, bits, code;
 133
 134             int alevel= ABS(level);
 135             int sign= (level>>31)&1;
 136
 137             if (alevel > rl->max_level[0][run])
 138                 code= 111; /*rl->n*/
 139             else
 140                 code= rl->index_run[0][run] + alevel - 1;
 141
 142             if (code < 111 /* rl->n */) {
 143                 /* store the vlc & sign at once */
 144                 len=   mpeg1_vlc[code][1]+1;
 145                 bits= (mpeg1_vlc[code][0]<<1) + sign;
 146             } else {
 147                 len=  mpeg1_vlc[111/*rl->n*/][1]+6;
 148                 bits= mpeg1_vlc[111/*rl->n*/][0]<<6;
 149
 150                 bits|= run;
 151                 if (alevel < 128) {
 152                     bits<<=8; len+=8;
 153                     bits|= level & 0xff;
 154                 } else {
 155                     bits<<=16; len+=16;
 156                     bits|= level & 0xff;
 157                     if (level < 0) {
 158                         bits|= 0x8001 + level + 255;
 159                     } else {
 160                         bits|= level & 0xffff;
 161                     }
 162                 }
 163             }
 164
 165             uni_ac_vlc_bits[UNI_AC_ENC_INDEX(run, i)]= bits;
 166             uni_ac_vlc_len [UNI_AC_ENC_INDEX(run, i)]= len;
 167         }
 168     }
 169 }
 170
 171 static void put_header(MpegEncContext *s, int header)
 172 {
 173     align_put_bits(&s->pb);
 174     put_bits(&s->pb, 16, header>>16);
 175     put_bits(&s->pb, 16, header&0xFFFF);
 176 }
 177
 178 /* put sequence header if needed */
 179 static void mpeg1_encode_sequence_header(MpegEncContext *s)
 180 {
 181         unsigned int vbv_buffer_size;
 182         unsigned int fps, v;
 183         int n, i;
 184         uint64_t time_code;
 185         float best_aspect_error= 1E10;
 186         float aspect_ratio= s->avctx->aspect_ratio;
 187
 188         if(aspect_ratio==0.0) aspect_ratio= s->width / (float)s->height; //pixel aspect 1:1 (VGA)
 189
 190         if (s->current_picture.key_frame) {
 191             /* mpeg1 header repeated every gop */
 192             put_header(s, SEQ_START_CODE);
 193
 194             /* search closest frame rate */
 195             {
 196                 int i, dmin, d;
 197                 s->frame_rate_index = 0;
 198                 dmin = 0x7fffffff;
 199                 for(i=1;i<14;i++) {
 200                     if(s->avctx->strict_std_compliance >= 0 && i>=9) break;
 201
 202                     d = abs(MPEG1_FRAME_RATE_BASE*(int64_t)s->avctx->frame_rate/s->avctx->frame_rate_base - frame_rate_tab[i]);
 203                     if (d < dmin) {
 204                         dmin = d;
 205                         s->frame_rate_index = i;
 206                     }
 207                 }
 208             }
 209
 210             put_bits(&s->pb, 12, s->width);
 211             put_bits(&s->pb, 12, s->height);
 212
 213             for(i=1; i<15; i++){
 214                 float error= mpeg1_aspect[i] - s->width/(s->height*aspect_ratio);
 215                 error= ABS(error);
 216
 217                 if(error < best_aspect_error){
 218                     best_aspect_error= error;
 219                     s->aspect_ratio_info= i;
 220                 }
 221             }
 222
 223             put_bits(&s->pb, 4, s->aspect_ratio_info);
 224             put_bits(&s->pb, 4, s->frame_rate_index);
 225             v = (s->bit_rate + 399) / 400;
 226             if (v > 0x3ffff)
 227                 v = 0x3ffff;
 228             put_bits(&s->pb, 18, v);
 229             put_bits(&s->pb, 1, 1); /* marker */
 230
 231             if(s->avctx->rc_buffer_size)
 232                 vbv_buffer_size = s->avctx->rc_buffer_size;
 233             else
 234                 /* VBV calculation: Scaled so that a VCD has the proper VBV size of 40 kilobytes */
 235                 vbv_buffer_size = (( 20 * s->bit_rate) / (1151929 / 2)) * 8 * 1024;
 236             put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384);
 237             put_bits(&s->pb, 1, 1); /* constrained parameter flag */
 238             put_bits(&s->pb, 1, 0); /* no custom intra matrix */
 239             put_bits(&s->pb, 1, 0); /* no custom non intra matrix */
 240
 241             put_header(s, GOP_START_CODE);
 242             put_bits(&s->pb, 1, 0); /* do drop frame */
 243             /* time code : we must convert from the real frame rate to a
 244                fake mpeg frame rate in case of low frame rate */
 245             fps = frame_rate_tab[s->frame_rate_index];
 246             time_code = (int64_t)s->fake_picture_number * MPEG1_FRAME_RATE_BASE;
 247             s->gop_picture_number = s->fake_picture_number;
 248             put_bits(&s->pb, 5, (uint32_t)((time_code / (fps * 3600)) % 24));
 249             put_bits(&s->pb, 6, (uint32_t)((time_code / (fps * 60)) % 60));
 250             put_bits(&s->pb, 1, 1);
 251             put_bits(&s->pb, 6, (uint32_t)((time_code / fps) % 60));
 252             put_bits(&s->pb, 6, (uint32_t)((time_code % fps) / MPEG1_FRAME_RATE_BASE));
 253             put_bits(&s->pb, 1, 1); /* closed gop */
 254             put_bits(&s->pb, 1, 0); /* broken link */
 255         }
 256
 257         if (s->avctx->frame_rate < (24 * s->avctx->frame_rate_base) && s->picture_number > 0) {
 258             /* insert empty P pictures to slow down to the desired
 259                frame rate. Each fake pictures takes about 20 bytes */
 260             fps = frame_rate_tab[s->frame_rate_index];
 261             n = av_rescale((int64_t)s->picture_number * s->avctx->frame_rate_base, fps, s->avctx->frame_rate) / MPEG1_FRAME_RATE_BASE - 1;
 262             while (s->fake_picture_number < n) {
 263                 mpeg1_skip_picture(s, s->fake_picture_number -
 264                                    s->gop_picture_number);
 265                 s->fake_picture_number++;
 266             }
 267
 268         }
 269 }
 270
 271 static inline void encode_mb_skip_run(MpegEncContext *s, int run){
 272     while (run >= 33) {
 273         put_bits(&s->pb, 11, 0x008);
 274         run -= 33;
 275     }
 276     put_bits(&s->pb, mbAddrIncrTable[run][1],
 277              mbAddrIncrTable[run][0]);
 278 }
 279
 280 /* insert a fake P picture */
 281 static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)
 282 {
 283     /* mpeg1 picture header */
 284     put_header(s, PICTURE_START_CODE);
 285     /* temporal reference */
 286     put_bits(&s->pb, 10, pict_num & 0x3ff);
 287
 288     put_bits(&s->pb, 3, P_TYPE);
 289     put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
 290
 291     put_bits(&s->pb, 1, 1); /* integer coordinates */
 292     put_bits(&s->pb, 3, 1); /* forward_f_code */
 293
 294     put_bits(&s->pb, 1, 0); /* extra bit picture */
 295
 296     /* only one slice */
 297     put_header(s, SLICE_MIN_START_CODE);
 298     put_bits(&s->pb, 5, 1); /* quantizer scale */
 299     put_bits(&s->pb, 1, 0); /* slice extra information */
 300
 301     encode_mb_skip_run(s, 0);
 302
 303     /* empty macroblock */
 304     put_bits(&s->pb, 3, 1); /* motion only */
 305
 306     /* zero motion x & y */
 307     put_bits(&s->pb, 1, 1);
 308     put_bits(&s->pb, 1, 1);
 309
 310     /* output a number of empty slice */
 311     encode_mb_skip_run(s, s->mb_width * s->mb_height - 2);
 312
 313     /* empty macroblock */
 314     put_bits(&s->pb, 3, 1); /* motion only */
 315
 316     /* zero motion x & y */
 317     put_bits(&s->pb, 1, 1);
 318     put_bits(&s->pb, 1, 1);
 319 }
 320 #endif
 321
 322 static void common_init(MpegEncContext *s)
 323 {
 324     s->y_dc_scale_table=
 325     s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
 326 }
 327
 328 void ff_mpeg1_clean_buffers(MpegEncContext *s){
 329     s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
 330     s->last_dc[1] = s->last_dc[0];
 331     s->last_dc[2] = s->last_dc[0];
 332     memset(s->last_mv, 0, sizeof(s->last_mv));
 333 }
 334
 335 #ifdef CONFIG_ENCODERS
 336
 337 void ff_mpeg1_encode_slice_header(MpegEncContext *s){
 338     put_header(s, SLICE_MIN_START_CODE + s->mb_y);
 339     put_bits(&s->pb, 5, s->qscale); /* quantizer scale */
 340     put_bits(&s->pb, 1, 0); /* slice extra information */
 341 }
 342
 343 void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
 344 {
 345     mpeg1_encode_sequence_header(s);
 346
 347     /* mpeg1 picture header */
 348     put_header(s, PICTURE_START_CODE);
 349     /* temporal reference */
 350
 351     // RAL: s->picture_number instead of s->fake_picture_number
 352     put_bits(&s->pb, 10, (s->picture_number -
 353                           s->gop_picture_number) & 0x3ff);
 354     s->fake_picture_number++;
 355
 356     put_bits(&s->pb, 3, s->pict_type);
 357     put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
 358
 359     // RAL: Forward f_code also needed for B frames
 360     if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
 361         put_bits(&s->pb, 1, 0); /* half pel coordinates */
 362         put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
 363     }
 364
 365     // RAL: Backward f_code necessary for B frames
 366     if (s->pict_type == B_TYPE) {
 367         put_bits(&s->pb, 1, 0); /* half pel coordinates */
 368         put_bits(&s->pb, 3, s->b_code); /* backward_f_code */
 369         }
 370
 371     put_bits(&s->pb, 1, 0); /* extra bit picture */
 372
 373     s->mb_y=0;
 374     ff_mpeg1_encode_slice_header(s);
 375 }
 376
 377 void mpeg1_encode_mb(MpegEncContext *s,
 378                      DCTELEM block[6][64],
 379                      int motion_x, int motion_y)
 380 {
 381     int i, cbp;
 382     const int mb_x = s->mb_x;
 383     const int mb_y = s->mb_y;
 384     const int first_mb= mb_x == s->resync_mb_x && mb_y == s->resync_mb_y;
 385
 386     /* compute cbp */
 387     cbp = 0;
 388     for(i=0;i<6;i++) {
 389         if (s->block_last_index[i] >= 0)
 390             cbp |= 1 << (5 - i);
 391     }
 392
 393     if (cbp == 0 && !first_mb && (mb_x != s->mb_width - 1 || mb_y != s->mb_height - 1) &&
 394         ((s->pict_type == P_TYPE && (motion_x | motion_y) == 0) ||
 395         (s->pict_type == B_TYPE && s->mv_dir == s->last_mv_dir && (((s->mv_dir & MV_DIR_FORWARD) ? ((s->mv[0][0][0] - s->last_mv[0][0][0])|(s->mv[0][0][1] - s->last_mv[0][0][1])) : 0) |
 396         ((s->mv_dir & MV_DIR_BACKWARD) ? ((s->mv[1][0][0] - s->last_mv[1][0][0])|(s->mv[1][0][1] - s->last_mv[1][0][1])) : 0)) == 0))) {
 397         s->mb_skip_run++;
 398         s->qscale -= s->dquant;
 399         s->skip_count++;
 400         s->misc_bits++;
 401         s->last_bits++;
 402     } else {
 403         if(first_mb){
 404             assert(s->mb_skip_run == 0);
 405             encode_mb_skip_run(s, s->mb_x);
 406         }else{
 407             encode_mb_skip_run(s, s->mb_skip_run);
 408         }
 409
 410         if (s->pict_type == I_TYPE) {
 411             if(s->dquant && cbp){
 412                 put_bits(&s->pb, 2, 1); /* macroblock_type : macroblock_quant = 1 */
 413                 put_bits(&s->pb, 5, s->qscale);
 414             }else{
 415                 put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */
 416                 s->qscale -= s->dquant;
 417             }
 418             s->misc_bits+= get_bits_diff(s);
 419             s->i_count++;
 420         } else if (s->mb_intra) {
 421             if(s->dquant && cbp){
 422                 put_bits(&s->pb, 6, 0x01);
 423                 put_bits(&s->pb, 5, s->qscale);
 424             }else{
 425                 put_bits(&s->pb, 5, 0x03);
 426                 s->qscale -= s->dquant;
 427             }
 428             s->misc_bits+= get_bits_diff(s);
 429             s->i_count++;
 430             s->last_mv[0][0][0] =
 431             s->last_mv[0][0][1] = 0;
 432         } else if (s->pict_type == P_TYPE) {
 433                 if (cbp != 0) {
 434                     if (motion_x == 0 && motion_y == 0) {
 435                         if(s->dquant){
 436                             put_bits(&s->pb, 5, 1); /* macroblock_pattern & quant */
 437                             put_bits(&s->pb, 5, s->qscale);
 438                         }else{
 439                             put_bits(&s->pb, 2, 1); /* macroblock_pattern only */
 440                         }
 441                         s->misc_bits+= get_bits_diff(s);
 442                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
 443                     } else {
 444                         if(s->dquant){
 445                             put_bits(&s->pb, 5, 2); /* motion + cbp */
 446                             put_bits(&s->pb, 5, s->qscale);
 447                         }else{
 448                             put_bits(&s->pb, 1, 1); /* motion + cbp */
 449                         }
 450                         s->misc_bits+= get_bits_diff(s);
 451                         mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);    // RAL: f_code parameter added
 452                         mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);    // RAL: f_code parameter added
 453                         s->mv_bits+= get_bits_diff(s);
 454                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
 455                     }
 456                 } else {
 457                     put_bits(&s->pb, 3, 1); /* motion only */
 458                     mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);    // RAL: f_code parameter added
 459                     mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);    // RAL: f_code parameter added
 460                     s->qscale -= s->dquant;
 461                     s->mv_bits+= get_bits_diff(s);
 462                 }
 463                 s->f_count++;
 464         } else
 465             {    // RAL: All the following bloc added for B frames:
 466                 if (cbp != 0)
 467                     {    // With coded bloc pattern
 468                     if (s->mv_dir == (MV_DIR_FORWARD | MV_DIR_BACKWARD))
 469                         {    // Bi-directional motion
 470                         if (s->dquant)
 471                             {    // With QScale
 472                             put_bits(&s->pb, 5, 2);
 473                             put_bits(&s->pb, 5, s->qscale);
 474                             }
 475                         else    // Without QScale
 476                             put_bits(&s->pb, 2, 3);
 477                         s->misc_bits += get_bits_diff(s);
 478                         mpeg1_encode_motion(s, s->mv[0][0][0] - s->last_mv[0][0][0], s->f_code);
 479                         mpeg1_encode_motion(s, s->mv[0][0][1] - s->last_mv[0][0][1], s->f_code);
 480                         mpeg1_encode_motion(s, s->mv[1][0][0] - s->last_mv[1][0][0], s->b_code);
 481                         mpeg1_encode_motion(s, s->mv[1][0][1] - s->last_mv[1][0][1], s->b_code);
 482                         s->b_count++;
 483                         s->f_count++;
 484                         s->mv_bits += get_bits_diff(s);
 485                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
 486                         }
 487                     else if (s->mv_dir == MV_DIR_BACKWARD)
 488                         {    // Backward motion
 489                         if (s->dquant)
 490                             {    // With QScale
 491                             put_bits(&s->pb, 6, 2);
 492                             put_bits(&s->pb, 5, s->qscale);
 493                             }
 494                         else    // Without QScale
 495                             put_bits(&s->pb, 3, 3);
 496                         s->misc_bits += get_bits_diff(s);
 497                         mpeg1_encode_motion(s, motion_x - s->last_mv[1][0][0], s->b_code);
 498                         mpeg1_encode_motion(s, motion_y - s->last_mv[1][0][1], s->b_code);
 499                         s->b_count++;
 500                         s->mv_bits += get_bits_diff(s);
 501                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
 502                         }
 503                     else if (s->mv_dir == MV_DIR_FORWARD)
 504                         {    // Forward motion
 505                         if (s->dquant)
 506                             {    // With QScale
 507                             put_bits(&s->pb, 6, 3);
 508                             put_bits(&s->pb, 5, s->qscale);
 509                             }
 510                         else    // Without QScale
 511                             put_bits(&s->pb, 4, 3);
 512                         s->misc_bits += get_bits_diff(s);
 513                         mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);
 514                         mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);
 515                         s->f_count++;
 516                         s->mv_bits += get_bits_diff(s);
 517                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
 518                         }
 519                     }
 520                 else
 521                     {    // No coded bloc pattern
 522                     if (s->mv_dir == (MV_DIR_FORWARD | MV_DIR_BACKWARD))
 523                         {    // Bi-directional motion
 524                         put_bits(&s->pb, 2, 2); /* backward & forward motion */
 525                         mpeg1_encode_motion(s, s->mv[0][0][0] - s->last_mv[0][0][0], s->f_code);
 526                         mpeg1_encode_motion(s, s->mv[0][0][1] - s->last_mv[0][0][1], s->f_code);
 527                         mpeg1_encode_motion(s, s->mv[1][0][0] - s->last_mv[1][0][0], s->b_code);
 528                         mpeg1_encode_motion(s, s->mv[1][0][1] - s->last_mv[1][0][1], s->b_code);
 529                         s->b_count++;
 530                         s->f_count++;
 531                         }
 532                     else if (s->mv_dir == MV_DIR_BACKWARD)
 533                         {    // Backward motion
 534                         put_bits(&s->pb, 3, 2); /* backward motion only */
 535                         mpeg1_encode_motion(s, motion_x - s->last_mv[1][0][0], s->b_code);
 536                         mpeg1_encode_motion(s, motion_y - s->last_mv[1][0][1], s->b_code);
 537                         s->b_count++;
 538                         }
 539                     else if (s->mv_dir == MV_DIR_FORWARD)
 540                         {    // Forward motion
 541                         put_bits(&s->pb, 4, 2); /* forward motion only */
 542                         mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);
 543                         mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);
 544                         s->f_count++;
 545                         }
 546                     s->qscale -= s->dquant;
 547                     s->mv_bits += get_bits_diff(s);
 548                     }
 549             // End of bloc from RAL
 550             }
 551         for(i=0;i<6;i++) {
 552             if (cbp & (1 << (5 - i))) {
 553                 mpeg1_encode_block(s, block[i], i);
 554             }
 555         }
 556         s->mb_skip_run = 0;
 557         if(s->mb_intra)
 558             s->i_tex_bits+= get_bits_diff(s);
 559         else
 560             s->p_tex_bits+= get_bits_diff(s);
 561     }
 562
 563     // RAL: By this:
 564     if (s->mv_dir & MV_DIR_FORWARD)
 565         {
 566         s->last_mv[0][0][0]= s->mv[0][0][0];
 567         s->last_mv[0][0][1]= s->mv[0][0][1];
 568         }
 569     if (s->mv_dir & MV_DIR_BACKWARD)
 570         {
 571         s->last_mv[1][0][0]= s->mv[1][0][0];
 572         s->last_mv[1][0][1]= s->mv[1][0][1];
 573         }
 574 }
 575
 576 // RAL: Parameter added: f_or_b_code
 577 static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code)
 578 {
 579     int code, bit_size, l, m, bits, range, sign;
 580
 581     if (val == 0) {
 582         /* zero vector */
 583         code = 0;
 584         put_bits(&s->pb,
 585                  mbMotionVectorTable[0][1],
 586                  mbMotionVectorTable[0][0]);
 587     } else {
 588         bit_size = f_or_b_code - 1;
 589         range = 1 << bit_size;
 590         /* modulo encoding */
 591         l = 16 * range;
 592         m = 2 * l;
 593         if (val < -l) {
 594             val += m;
 595         } else if (val >= l) {
 596             val -= m;
 597         }
 598
 599         if (val >= 0) {
 600             val--;
 601             code = (val >> bit_size) + 1;
 602             bits = val & (range - 1);
 603             sign = 0;
 604         } else {
 605             val = -val;
 606             val--;
 607             code = (val >> bit_size) + 1;
 608             bits = val & (range - 1);
 609             sign = 1;
 610         }
 611
 612         assert(code > 0 && code <= 16);
 613
 614         put_bits(&s->pb,
 615                  mbMotionVectorTable[code][1],
 616                  mbMotionVectorTable[code][0]);
 617
 618         put_bits(&s->pb, 1, sign);
 619         if (bit_size > 0) {
 620             put_bits(&s->pb, bit_size, bits);
 621         }
 622     }
 623 }
 624
 625 void ff_mpeg1_encode_init(MpegEncContext *s)
 626 {
 627     static int done=0;
 628
 629     common_init(s);
 630
 631     if(!done){
 632         int f_code;
 633         int mv;
 634         int i;
 635
 636         done=1;
 637         init_rl(&rl_mpeg1);
 638
 639         for(i=0; i<64; i++)
 640         {
 641                 mpeg1_max_level[0][i]= rl_mpeg1.max_level[0][i];
 642                 mpeg1_index_run[0][i]= rl_mpeg1.index_run[0][i];
 643         }
 644
 645         init_uni_ac_vlc(&rl_mpeg1, uni_mpeg1_ac_vlc_bits, uni_mpeg1_ac_vlc_len);
 646
 647         /* build unified dc encoding tables */
 648         for(i=-255; i<256; i++)
 649         {
 650                 int adiff, index;
 651                 int bits, code;
 652                 int diff=i;
 653
 654                 adiff = ABS(diff);
 655                 if(diff<0) diff--;
 656                 index = vlc_dc_table[adiff];
 657
 658                 bits= vlc_dc_lum_bits[index] + index;
 659                 code= (vlc_dc_lum_code[index]<<index) + (diff & ((1 << index) - 1));
 660                 mpeg1_lum_dc_uni[i+255]= bits + (code<<8);
 661
 662                 bits= vlc_dc_chroma_bits[index] + index;
 663                 code= (vlc_dc_chroma_code[index]<<index) + (diff & ((1 << index) - 1));
 664                 mpeg1_chr_dc_uni[i+255]= bits + (code<<8);
 665         }
 666
 667         mv_penalty= av_mallocz( sizeof(uint8_t)*(MAX_FCODE+1)*(2*MAX_MV+1) );
 668
 669         for(f_code=1; f_code<=MAX_FCODE; f_code++){
 670             for(mv=-MAX_MV; mv<=MAX_MV; mv++){
 671                 int len;
 672
 673                 if(mv==0) len= mbMotionVectorTable[0][1];
 674                 else{
 675                     int val, bit_size, range, code;
 676
 677                     bit_size = s->f_code - 1;
 678                     range = 1 << bit_size;
 679
 680                     val=mv;
 681                     if (val < 0)
 682                         val = -val;
 683                     val--;
 684                     code = (val >> bit_size) + 1;
 685                     if(code<17){
 686                         len= mbMotionVectorTable[code][1] + 1 + bit_size;
 687                     }else{
 688                         len= mbMotionVectorTable[16][1] + 2 + bit_size;
 689                     }
 690                 }
 691
 692                 mv_penalty[f_code][mv+MAX_MV]= len;
 693             }
 694         }
 695
 696
 697         for(f_code=MAX_FCODE; f_code>0; f_code--){
 698             for(mv=-(8<<f_code); mv<(8<<f_code); mv++){
 699                 fcode_tab[mv+MAX_MV]= f_code;
 700             }
 701         }
 702     }
 703     s->me.mv_penalty= mv_penalty;
 704     s->fcode_tab= fcode_tab;
 705     s->min_qcoeff=-255;
 706     s->max_qcoeff= 255;
 707     s->intra_ac_vlc_length=
 708     s->inter_ac_vlc_length= uni_mpeg1_ac_vlc_len;
 709 }
 710
 711 static inline void encode_dc(MpegEncContext *s, int diff, int component)
 712 {
 713     if (component == 0) {
 714         put_bits(
 715             &s->pb,
 716             mpeg1_lum_dc_uni[diff+255]&0xFF,
 717             mpeg1_lum_dc_uni[diff+255]>>8);
 718     } else {
 719         put_bits(
 720             &s->pb,
 721             mpeg1_chr_dc_uni[diff+255]&0xFF,
 722             mpeg1_chr_dc_uni[diff+255]>>8);
 723     }
 724 }
 725
 726 static void mpeg1_encode_block(MpegEncContext *s,
 727                                DCTELEM *block,
 728                                int n)
 729 {
 730     int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign;
 731     int code, component;
 732 //    RLTable *rl = &rl_mpeg1;
 733
 734     last_index = s->block_last_index[n];
 735
 736     /* DC coef */
 737     if (s->mb_intra) {
 738         component = (n <= 3 ? 0 : n - 4 + 1);
 739         dc = block[0]; /* overflow is impossible */
 740         diff = dc - s->last_dc[component];
 741         encode_dc(s, diff, component);
 742         s->last_dc[component] = dc;
 743         i = 1;
 744     } else {
 745         /* encode the first coefficient : needs to be done here because
 746            it is handled slightly differently */
 747         level = block[0];
 748         if (abs(level) == 1) {
 749                 code = ((uint32_t)level >> 31); /* the sign bit */
 750                 put_bits(&s->pb, 2, code | 0x02);
 751                 i = 1;
 752         } else {
 753             i = 0;
 754             last_non_zero = -1;
 755             goto next_coef;
 756         }
 757     }
 758
 759     /* now quantify & encode AC coefs */
 760     last_non_zero = i - 1;
 761
 762     for(;i<=last_index;i++) {
 763         j = s->intra_scantable.permutated[i];
 764         level = block[j];
 765     next_coef:
 766 #if 0
 767         if (level != 0)
 768             dprintf("level[%d]=%d\n", i, level);
 769 #endif
 770         /* encode using VLC */
 771         if (level != 0) {
 772             run = i - last_non_zero - 1;
 773
 774             alevel= level;
 775             MASK_ABS(sign, alevel)
 776             sign&=1;
 777
 778 //            code = get_rl_index(rl, 0, run, alevel);
 779             if (alevel <= mpeg1_max_level[0][run]){
 780                 code= mpeg1_index_run[0][run] + alevel - 1;
 781                 /* store the vlc & sign at once */
 782                 put_bits(&s->pb, mpeg1_vlc[code][1]+1, (mpeg1_vlc[code][0]<<1) + sign);
 783             } else {
 784                 /* escape seems to be pretty rare <5% so i dont optimize it */
 785                 put_bits(&s->pb, mpeg1_vlc[111/*rl->n*/][1], mpeg1_vlc[111/*rl->n*/][0]);
 786                 /* escape: only clip in this case */
 787                 put_bits(&s->pb, 6, run);
 788                 if (alevel < 128) {
 789                     put_bits(&s->pb, 8, level & 0xff);
 790                 } else {
 791                     if (level < 0) {
 792                         put_bits(&s->pb, 16, 0x8001 + level + 255);
 793                     } else {
 794                         put_bits(&s->pb, 16, level & 0xffff);
 795                     }
 796                 }
 797             }
 798             last_non_zero = i;
 799         }
 800     }
 801     /* end of block */
 802     put_bits(&s->pb, 2, 0x2);
 803 }
 804 #endif //CONFIG_ENCODERS
 805
 806 /******************************************/
 807 /* decoding */
 808
 809 static VLC dc_lum_vlc;
 810 static VLC dc_chroma_vlc;
 811 static VLC mv_vlc;
 812 static VLC mbincr_vlc;
 813 static VLC mb_ptype_vlc;
 814 static VLC mb_btype_vlc;
 815 static VLC mb_pat_vlc;
 816
 817 static void init_vlcs(MpegEncContext *s)
 818 {
 819     static int done = 0;
 820
 821     if (!done) {
 822         done = 1;
 823
 824         init_vlc(&dc_lum_vlc, DC_VLC_BITS, 12,
 825                  vlc_dc_lum_bits, 1, 1,
 826                  vlc_dc_lum_code, 2, 2);
 827         init_vlc(&dc_chroma_vlc,  DC_VLC_BITS, 12,
 828                  vlc_dc_chroma_bits, 1, 1,
 829                  vlc_dc_chroma_code, 2, 2);
 830         init_vlc(&mv_vlc, MV_VLC_BITS, 17,
 831                  &mbMotionVectorTable[0][1], 2, 1,
 832                  &mbMotionVectorTable[0][0], 2, 1);
 833         init_vlc(&mbincr_vlc, MBINCR_VLC_BITS, 36,
 834                  &mbAddrIncrTable[0][1], 2, 1,
 835                  &mbAddrIncrTable[0][0], 2, 1);
 836         init_vlc(&mb_pat_vlc, MB_PAT_VLC_BITS, 63,
 837                  &mbPatTable[0][1], 2, 1,
 838                  &mbPatTable[0][0], 2, 1);
 839
 840         init_vlc(&mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
 841                  &table_mb_ptype[0][1], 2, 1,
 842                  &table_mb_ptype[0][0], 2, 1);
 843         init_vlc(&mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
 844                  &table_mb_btype[0][1], 2, 1,
 845                  &table_mb_btype[0][0], 2, 1);
 846         init_rl(&rl_mpeg1);
 847         init_rl(&rl_mpeg2);
 848
 849         init_2d_vlc_rl(&rl_mpeg1);
 850         init_2d_vlc_rl(&rl_mpeg2);
 851     }
 852 }
 853
 854 static inline int get_dmv(MpegEncContext *s)
 855 {
 856     if(get_bits1(&s->gb))
 857         return 1 - (get_bits1(&s->gb) << 1);
 858     else
 859         return 0;
 860 }
 861
 862 static inline int get_qscale(MpegEncContext *s)
 863 {
 864     int qscale = get_bits(&s->gb, 5);
 865     if (s->mpeg2) {
 866         if (s->q_scale_type) {
 867             return non_linear_qscale[qscale];
 868         } else {
 869             return qscale << 1;
 870         }
 871     }
 872     return qscale;
 873 }
 874
 875 /* motion type (for mpeg2) */
 876 #define MT_FIELD 1
 877 #define MT_FRAME 2
 878 #define MT_16X8  2
 879 #define MT_DMV   3
 880
 881 static int mpeg_decode_mb(MpegEncContext *s,
 882                           DCTELEM block[6][64])
 883 {
 884     int i, j, k, cbp, val, mb_type, motion_type;
 885
 886     dprintf("decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y);
 887
 888     assert(s->mb_skiped==0);
 889
 890     if (s->mb_skip_run-- != 0) {
 891         if(s->pict_type == I_TYPE){
 892             fprintf(stderr, "skiped MB in I frame at %d %d\n", s->mb_x, s->mb_y);
 893             return -1;
 894         }
 895
 896         /* skip mb */
 897         s->mb_intra = 0;
 898         for(i=0;i<6;i++)
 899             s->block_last_index[i] = -1;
 900         s->mv_type = MV_TYPE_16X16;
 901         if (s->pict_type == P_TYPE) {
 902             /* if P type, zero motion vector is implied */
 903             s->mv_dir = MV_DIR_FORWARD;
 904             s->mv[0][0][0] = s->mv[0][0][1] = 0;
 905             s->last_mv[0][0][0] = s->last_mv[0][0][1] = 0;
 906             s->last_mv[0][1][0] = s->last_mv[0][1][1] = 0;
 907             s->mb_skiped = 1;
 908             s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride ]= MB_TYPE_SKIP | MB_TYPE_L0 | MB_TYPE_16x16;
 909         } else {
 910             /* if B type, reuse previous vectors and directions */
 911             s->mv[0][0][0] = s->last_mv[0][0][0];
 912             s->mv[0][0][1] = s->last_mv[0][0][1];
 913             s->mv[1][0][0] = s->last_mv[1][0][0];
 914             s->mv[1][0][1] = s->last_mv[1][0][1];
 915
 916             s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride ]=
 917                 s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride - 1] | MB_TYPE_SKIP;
 918 //            assert(s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride - 1]&(MB_TYPE_16x16|MB_TYPE_16x8));
 919
 920             if((s->mv[0][0][0]|s->mv[0][0][1]|s->mv[1][0][0]|s->mv[1][0][1])==0)
 921                 s->mb_skiped = 1;
 922         }
 923
 924         return 0;
 925     }
 926
 927     switch(s->pict_type) {
 928     default:
 929     case I_TYPE:
 930         if (get_bits1(&s->gb) == 0) {
 931             if (get_bits1(&s->gb) == 0){
 932                 fprintf("invalid mb type in I Frame at %d %d\n", s->mb_x, s->mb_y);
 933                 return -1;
 934             }
 935             mb_type = MB_TYPE_QUANT | MB_TYPE_INTRA;
 936         } else {
 937             mb_type = MB_TYPE_INTRA;
 938         }
 939         break;
 940     case P_TYPE:
 941         mb_type = get_vlc2(&s->gb, mb_ptype_vlc.table, MB_PTYPE_VLC_BITS, 1);
 942         if (mb_type < 0){
 943             fprintf(stderr, "invalid mb type in P Frame at %d %d\n", s->mb_x, s->mb_y);
 944             return -1;
 945         }
 946         mb_type = ptype2mb_type[ mb_type ];
 947         break;
 948     case B_TYPE:
 949         mb_type = get_vlc2(&s->gb, mb_btype_vlc.table, MB_BTYPE_VLC_BITS, 1);
 950         if (mb_type < 0){
 951             fprintf(stderr, "invalid mb type in B Frame at %d %d\n", s->mb_x, s->mb_y);
 952             return -1;
 953         }
 954         mb_type = btype2mb_type[ mb_type ];
 955         break;
 956     }
 957     dprintf("mb_type=%x\n", mb_type);
 958 //    motion_type = 0; /* avoid warning */
 959     if (IS_INTRA(mb_type)) {
 960         /* compute dct type */
 961         if (s->picture_structure == PICT_FRAME && //FIXME add a interlaced_dct coded var?
 962             !s->frame_pred_frame_dct) {
 963             s->interlaced_dct = get_bits1(&s->gb);
 964         }
 965
 966         if (IS_QUANT(mb_type))
 967             s->qscale = get_qscale(s);
 968
 969         if (s->concealment_motion_vectors) {
 970             /* just parse them */
 971             if (s->picture_structure != PICT_FRAME)
 972                 skip_bits1(&s->gb); /* field select */
 973
 974             s->mv[0][0][0]= s->last_mv[0][0][0]= s->last_mv[0][1][0] =
 975                 mpeg_decode_motion(s, s->mpeg_f_code[0][0], s->last_mv[0][0][0]);
 976             s->mv[0][0][1]= s->last_mv[0][0][1]= s->last_mv[0][1][1] =
 977                 mpeg_decode_motion(s, s->mpeg_f_code[0][1], s->last_mv[0][0][1]);
 978
 979             skip_bits1(&s->gb); /* marker */
 980         }else
 981             memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */
 982         s->mb_intra = 1;
 983
 984         if (s->mpeg2) {
 985             for(i=0;i<6;i++) {
 986                 if (mpeg2_decode_block_intra(s, block[i], i) < 0)
 987                     return -1;
 988             }
 989         } else {
 990             for(i=0;i<6;i++) {
 991                 if (mpeg1_decode_block_intra(s, block[i], i) < 0)
 992                     return -1;
 993             }
 994         }
 995     } else {
 996         if (mb_type & MB_TYPE_ZERO_MV){
 997             assert(mb_type & MB_TYPE_PAT);
 998
 999             /* compute dct type */
1000             if (s->picture_structure == PICT_FRAME && //FIXME add a interlaced_dct coded var?
1001                 !s->frame_pred_frame_dct) {
1002                 s->interlaced_dct = get_bits1(&s->gb);
1003             }
1004
1005             if (IS_QUANT(mb_type))
1006                 s->qscale = get_qscale(s);
1007
1008             s->mv_dir = MV_DIR_FORWARD;
1009             s->mv_type = MV_TYPE_16X16;
1010             s->last_mv[0][0][0] = 0;
1011             s->last_mv[0][0][1] = 0;
1012             s->last_mv[0][1][0] = 0;
1013             s->last_mv[0][1][1] = 0;
1014             s->mv[0][0][0] = 0;
1015             s->mv[0][0][1] = 0;
1016         }else{
1017             assert(mb_type & MB_TYPE_L0L1);
1018 //FIXME decide if MBs in field pictures are MB_TYPE_INTERLACED
1019             /* get additionnal motion vector type */
1020             if (s->frame_pred_frame_dct)
1021                 motion_type = MT_FRAME;
1022             else{
1023                 motion_type = get_bits(&s->gb, 2);
1024             }
1025
1026             /* compute dct type */
1027             if (s->picture_structure == PICT_FRAME && //FIXME add a interlaced_dct coded var?
1028                 !s->frame_pred_frame_dct && IS_PAT(mb_type)) {
1029                 s->interlaced_dct = get_bits1(&s->gb);
1030             }
1031
1032             if (IS_QUANT(mb_type))
1033                 s->qscale = get_qscale(s);
1034
1035             /* motion vectors */
1036             s->mv_dir = 0;
1037             for(i=0;i<2;i++) {
1038                 if (USES_LIST(mb_type, i)) {
1039                     s->mv_dir |= (MV_DIR_FORWARD >> i);
1040                     dprintf("motion_type=%d\n", motion_type);
1041                     switch(motion_type) {
1042                     case MT_FRAME: /* or MT_16X8 */
1043                         if (s->picture_structure == PICT_FRAME) {
1044                             /* MT_FRAME */
1045                             mb_type |= MB_TYPE_16x16;
1046                             s->mv_type = MV_TYPE_16X16;
1047                             s->mv[i][0][0]= s->last_mv[i][0][0]= s->last_mv[i][1][0] =
1048                                 mpeg_decode_motion(s, s->mpeg_f_code[i][0], s->last_mv[i][0][0]);
1049                             s->mv[i][0][1]= s->last_mv[i][0][1]= s->last_mv[i][1][1] =
1050                                 mpeg_decode_motion(s, s->mpeg_f_code[i][1], s->last_mv[i][0][1]);
1051                             /* full_pel: only for mpeg1 */
1052                             if (s->full_pel[i]){
1053                                 s->mv[i][0][0] <<= 1;
1054                                 s->mv[i][0][1] <<= 1;
1055                             }
1056                         } else {
1057                             /* MT_16X8 */
1058                             mb_type |= MB_TYPE_16x8;
1059                             s->mv_type = MV_TYPE_16X8;
1060                             for(j=0;j<2;j++) {
1061                                 s->field_select[i][j] = get_bits1(&s->gb);
1062                                 for(k=0;k<2;k++) {
1063                                     val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
1064                                                              s->last_mv[i][j][k]);
1065                                     s->last_mv[i][j][k] = val;
1066                                     s->mv[i][j][k] = val;
1067                                 }
1068                             }
1069                         }
1070                         break;
1071                     case MT_FIELD:
1072                         s->mv_type = MV_TYPE_FIELD;
1073                         if (s->picture_structure == PICT_FRAME) {
1074                             mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
1075                             for(j=0;j<2;j++) {
1076                                 s->field_select[i][j] = get_bits1(&s->gb);
1077                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
1078                                                          s->last_mv[i][j][0]);
1079                                 s->last_mv[i][j][0] = val;
1080                                 s->mv[i][j][0] = val;
1081                                 dprintf("fmx=%d\n", val);
1082                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
1083                                                          s->last_mv[i][j][1] >> 1);
1084                                 s->last_mv[i][j][1] = val << 1;
1085                                 s->mv[i][j][1] = val;
1086                                 dprintf("fmy=%d\n", val);
1087                             }
1088                         } else {
1089                             mb_type |= MB_TYPE_16x16;
1090                             s->field_select[i][0] = get_bits1(&s->gb);
1091                             for(k=0;k<2;k++) {
1092                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
1093                                                          s->last_mv[i][0][k]);
1094                                 s->last_mv[i][0][k] = val;
1095                                 s->last_mv[i][1][k] = val;
1096                                 s->mv[i][0][k] = val;
1097                             }
1098                         }
1099                         break;
1100                     case MT_DMV:
1101                         {
1102                             int dmx, dmy, mx, my, m;
1103
1104                             mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
1105                                                     s->last_mv[i][0][0]);
1106                             s->last_mv[i][0][0] = mx;
1107                             s->last_mv[i][1][0] = mx;
1108                             dmx = get_dmv(s);
1109                             my = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
1110                                                     s->last_mv[i][0][1] >> 1);
1111                             dmy = get_dmv(s);
1112                             s->mv_type = MV_TYPE_DMV;
1113
1114
1115                             s->last_mv[i][0][1] = my<<1;
1116                             s->last_mv[i][1][1] = my<<1;
1117
1118                             s->mv[i][0][0] = mx;
1119                             s->mv[i][0][1] = my;
1120                             s->mv[i][1][0] = mx;//not used
1121                             s->mv[i][1][1] = my;//not used
1122
1123                             if (s->picture_structure == PICT_FRAME) {
1124                                 mb_type |= MB_TYPE_16x16 | MB_TYPE_INTERLACED;
1125
1126                                 //m = 1 + 2 * s->top_field_first;
1127                                 m = s->top_field_first ? 1 : 3;
1128
1129                                 /* top -> top pred */
1130                                 s->mv[i][2][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
1131                                 s->mv[i][2][1] = ((my * m + (my > 0)) >> 1) + dmy - 1;
1132                                 m = 4 - m;
1133                                 s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
1134                                 s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1;
1135                             } else {
1136                                 mb_type |= MB_TYPE_16x16;
1137
1138                                 s->mv[i][2][0] = ((mx + (mx > 0)) >> 1) + dmx;
1139                                 s->mv[i][2][1] = ((my + (my > 0)) >> 1) + dmy;
1140                                 if(s->picture_structure == PICT_TOP_FIELD)
1141                                     s->mv[i][2][1]--;
1142                                 else
1143                                     s->mv[i][2][1]++;
1144                             }
1145                         }
1146                         break;
1147                     }
1148                 }
1149             }
1150         }
1151
1152         s->mb_intra = 0;
1153
1154         if (IS_PAT(mb_type)) {
1155             cbp = get_vlc2(&s->gb, mb_pat_vlc.table, MB_PAT_VLC_BITS, 1);
1156             if (cbp < 0){
1157                 fprintf(stderr, "invalid cbp at %d %d\n", s->mb_x, s->mb_y);
1158                 return -1;
1159             }
1160             cbp++;
1161
1162             if (s->mpeg2) {
1163                 for(i=0;i<6;i++) {
1164                     if (cbp & 32) {
1165                         if (mpeg2_decode_block_non_intra(s, block[i], i) < 0)
1166                             return -1;
1167                     } else {
1168                         s->block_last_index[i] = -1;
1169                     }
1170                     cbp+=cbp;
1171                 }
1172             } else {
1173                 for(i=0;i<6;i++) {
1174                     if (cbp & 32) {
1175                         if (mpeg1_decode_block_inter(s, block[i], i) < 0)
1176                             return -1;
1177                     } else {
1178                         s->block_last_index[i] = -1;
1179                     }
1180                     cbp+=cbp;
1181                 }
1182             }
1183         }else{
1184             for(i=0;i<6;i++)
1185                 s->block_last_index[i] = -1;
1186         }
1187     }
1188
1189     s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride ]= mb_type;
1190
1191     return 0;
1192 }
1193
1194 /* as h263, but only 17 codes */
1195 static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
1196 {
1197     int code, sign, val, l, shift;
1198
1199     code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
1200     if (code == 0) {
1201         return pred;
1202     }
1203     if (code < 0) {
1204         return 0xffff;
1205     }
1206
1207     sign = get_bits1(&s->gb);
1208     shift = fcode - 1;
1209     val = code;
1210     if (shift) {
1211         val = (val - 1) << shift;
1212         val |= get_bits(&s->gb, shift);
1213         val++;
1214     }
1215     if (sign)
1216         val = -val;
1217     val += pred;
1218
1219     /* modulo decoding */
1220     l = 1 << (shift+4);
1221     val = ((val + l)&(l*2-1)) - l;
1222     return val;
1223 }
1224
1225 static inline int decode_dc(MpegEncContext *s, int component)
1226 {
1227     int code, diff;
1228
1229     if (component == 0) {
1230         code = get_vlc2(&s->gb, dc_lum_vlc.table, DC_VLC_BITS, 2);
1231     } else {
1232         code = get_vlc2(&s->gb, dc_chroma_vlc.table, DC_VLC_BITS, 2);
1233     }
1234     if (code < 0){
1235         fprintf(stderr, "invalid dc code at %d %d\n", s->mb_x, s->mb_y);
1236         return 0xffff;
1237     }
1238     if (code == 0) {
1239         diff = 0;
1240     } else {
1241         diff = get_xbits(&s->gb, code);
1242     }
1243     return diff;
1244 }
1245
1246 static inline int mpeg1_decode_block_intra(MpegEncContext *s,
1247                                DCTELEM *block,
1248                                int n)
1249 {
1250     int level, dc, diff, i, j, run;
1251     int component;
1252     RLTable *rl = &rl_mpeg1;
1253     uint8_t * const scantable= s->intra_scantable.permutated;
1254     const uint16_t *quant_matrix= s->intra_matrix;
1255     const int qscale= s->qscale;
1256
1257     /* DC coef */
1258     component = (n <= 3 ? 0 : n - 4 + 1);
1259     diff = decode_dc(s, component);
1260     if (diff >= 0xffff)
1261         return -1;
1262     dc = s->last_dc[component];
1263     dc += diff;
1264     s->last_dc[component] = dc;
1265     block[0] = dc<<3;
1266     dprintf("dc=%d diff=%d\n", dc, diff);
1267     i = 0;
1268     {
1269         OPEN_READER(re, &s->gb);
1270         /* now quantify & encode AC coefs */
1271         for(;;) {
1272             UPDATE_CACHE(re, &s->gb);
1273             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
1274
1275             if(level == 127){
1276                 break;
1277             } else if(level != 0) {
1278                 i += run;
1279                 j = scantable[i];
1280                 level= (level*qscale*quant_matrix[j])>>3;
1281                 level= (level-1)|1;
1282                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1283                 LAST_SKIP_BITS(re, &s->gb, 1);
1284             } else {
1285                 /* escape */
1286                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
1287                 UPDATE_CACHE(re, &s->gb);
1288                 level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
1289                 if (level == -128) {
1290                     level = SHOW_UBITS(re, &s->gb, 8) - 256; LAST_SKIP_BITS(re, &s->gb, 8);
1291                 } else if (level == 0) {
1292                     level = SHOW_UBITS(re, &s->gb, 8)      ; LAST_SKIP_BITS(re, &s->gb, 8);
1293                 }
1294                 i += run;
1295                 j = scantable[i];
1296                 if(level<0){
1297                     level= -level;
1298                     level= (level*qscale*quant_matrix[j])>>3;
1299                     level= (level-1)|1;
1300                     level= -level;
1301                 }else{
1302                     level= (level*qscale*quant_matrix[j])>>3;
1303                     level= (level-1)|1;
1304                 }
1305             }
1306             if (i > 63){
1307                 fprintf(stderr, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1308                 return -1;
1309             }
1310
1311             block[j] = level;
1312         }
1313         CLOSE_READER(re, &s->gb);
1314     }
1315     s->block_last_index[n] = i;
1316    return 0;
1317 }
1318
1319 static inline int mpeg1_decode_block_inter(MpegEncContext *s,
1320                                DCTELEM *block,
1321                                int n)
1322 {
1323     int level, i, j, run;
1324     RLTable *rl = &rl_mpeg1;
1325     uint8_t * const scantable= s->intra_scantable.permutated;
1326     const uint16_t *quant_matrix= s->inter_matrix;
1327     const int qscale= s->qscale;
1328
1329     {
1330         int v;
1331         OPEN_READER(re, &s->gb);
1332         i = -1;
1333         /* special case for the first coef. no need to add a second vlc table */
1334         UPDATE_CACHE(re, &s->gb);
1335         v= SHOW_UBITS(re, &s->gb, 2);
1336         if (v & 2) {
1337             LAST_SKIP_BITS(re, &s->gb, 2);
1338             level= (3*qscale*quant_matrix[0])>>4;
1339             level= (level-1)|1;
1340             if(v&1)
1341                 level= -level;
1342             block[0] = level;
1343             i++;
1344         }
1345
1346         /* now quantify & encode AC coefs */
1347         for(;;) {
1348             UPDATE_CACHE(re, &s->gb);
1349             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
1350
1351             if(level == 127){
1352                 break;
1353             } else if(level != 0) {
1354                 i += run;
1355                 j = scantable[i];
1356                 level= ((level*2+1)*qscale*quant_matrix[j])>>4;
1357                 level= (level-1)|1;
1358                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1359                 LAST_SKIP_BITS(re, &s->gb, 1);
1360             } else {
1361                 /* escape */
1362                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
1363                 UPDATE_CACHE(re, &s->gb);
1364                 level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
1365                 if (level == -128) {
1366                     level = SHOW_UBITS(re, &s->gb, 8) - 256; LAST_SKIP_BITS(re, &s->gb, 8);
1367                 } else if (level == 0) {
1368                     level = SHOW_UBITS(re, &s->gb, 8)      ; LAST_SKIP_BITS(re, &s->gb, 8);
1369                 }
1370                 i += run;
1371                 j = scantable[i];
1372                 if(level<0){
1373                     level= -level;
1374                     level= ((level*2+1)*qscale*quant_matrix[j])>>4;
1375                     level= (level-1)|1;
1376                     level= -level;
1377                 }else{
1378                     level= ((level*2+1)*qscale*quant_matrix[j])>>4;
1379                     level= (level-1)|1;
1380                 }
1381             }
1382             if (i > 63){
1383                 fprintf(stderr, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1384                 return -1;
1385             }
1386
1387             block[j] = level;
1388         }
1389         CLOSE_READER(re, &s->gb);
1390     }
1391     s->block_last_index[n] = i;
1392     return 0;
1393 }
1394
1395 /* Also does unquantization here, since I will never support mpeg2
1396    encoding */
1397 static inline int mpeg2_decode_block_non_intra(MpegEncContext *s,
1398                                DCTELEM *block,
1399                                int n)
1400 {
1401     int level, i, j, run;
1402     RLTable *rl = &rl_mpeg1;
1403     uint8_t * const scantable= s->intra_scantable.permutated;
1404     const uint16_t *quant_matrix;
1405     const int qscale= s->qscale;
1406     int mismatch;
1407
1408     mismatch = 1;
1409
1410     {
1411         int v;
1412         OPEN_READER(re, &s->gb);
1413         i = -1;
1414         if (n < 4)
1415             quant_matrix = s->inter_matrix;
1416         else
1417             quant_matrix = s->chroma_inter_matrix;
1418
1419         /* special case for the first coef. no need to add a second vlc table */
1420         UPDATE_CACHE(re, &s->gb);
1421         v= SHOW_UBITS(re, &s->gb, 2);
1422         if (v & 2) {
1423             LAST_SKIP_BITS(re, &s->gb, 2);
1424             level= (3*qscale*quant_matrix[0])>>5;
1425             if(v&1)
1426                 level= -level;
1427             block[0] = level;
1428             mismatch ^= level;
1429             i++;
1430         }
1431
1432         /* now quantify & encode AC coefs */
1433         for(;;) {
1434             UPDATE_CACHE(re, &s->gb);
1435             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
1436
1437             if(level == 127){
1438                 break;
1439             } else if(level != 0) {
1440                 i += run;
1441                 j = scantable[i];
1442                 level= ((level*2+1)*qscale*quant_matrix[j])>>5;
1443                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1444                 LAST_SKIP_BITS(re, &s->gb, 1);
1445             } else {
1446                 /* escape */
1447                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
1448                 UPDATE_CACHE(re, &s->gb);
1449                 level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
1450
1451                 i += run;
1452                 j = scantable[i];
1453                 if(level<0){
1454                     level= ((-level*2+1)*qscale*quant_matrix[j])>>5;
1455                     level= -level;
1456                 }else{
1457                     level= ((level*2+1)*qscale*quant_matrix[j])>>5;
1458                 }
1459             }
1460             if (i > 63){
1461                 fprintf(stderr, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1462                 return -1;
1463             }
1464
1465             mismatch ^= level;
1466             block[j] = level;
1467         }
1468         CLOSE_READER(re, &s->gb);
1469     }
1470     block[63] ^= (mismatch & 1);
1471
1472     s->block_last_index[n] = i;
1473     return 0;
1474 }
1475
1476 static inline int mpeg2_decode_block_intra(MpegEncContext *s,
1477                                DCTELEM *block,
1478                                int n)
1479 {
1480     int level, dc, diff, i, j, run;
1481     int component;
1482     RLTable *rl;
1483     uint8_t * const scantable= s->intra_scantable.permutated;
1484     const uint16_t *quant_matrix;
1485     const int qscale= s->qscale;
1486     int mismatch;
1487
1488     /* DC coef */
1489     if (n < 4){
1490         quant_matrix = s->intra_matrix;
1491         component = 0;
1492     }else{
1493         quant_matrix = s->chroma_intra_matrix;
1494         component = n - 3;
1495     }
1496     diff = decode_dc(s, component);
1497     if (diff >= 0xffff)
1498         return -1;
1499     dc = s->last_dc[component];
1500     dc += diff;
1501     s->last_dc[component] = dc;
1502     block[0] = dc << (3 - s->intra_dc_precision);
1503     dprintf("dc=%d\n", block[0]);
1504     mismatch = block[0] ^ 1;
1505     i = 0;
1506     if (s->intra_vlc_format)
1507         rl = &rl_mpeg2;
1508     else
1509         rl = &rl_mpeg1;
1510
1511     {
1512         OPEN_READER(re, &s->gb);
1513         /* now quantify & encode AC coefs */
1514         for(;;) {
1515             UPDATE_CACHE(re, &s->gb);
1516             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
1517
1518             if(level == 127){
1519                 break;
1520             } else if(level != 0) {
1521                 i += run;
1522                 j = scantable[i];
1523                 level= (level*qscale*quant_matrix[j])>>4;
1524                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1525                 LAST_SKIP_BITS(re, &s->gb, 1);
1526             } else {
1527                 /* escape */
1528                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
1529                 UPDATE_CACHE(re, &s->gb);
1530                 level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
1531                 i += run;
1532                 j = scantable[i];
1533                 if(level<0){
1534                     level= (-level*qscale*quant_matrix[j])>>4;
1535                     level= -level;
1536                 }else{
1537                     level= (level*qscale*quant_matrix[j])>>4;
1538                 }
1539             }
1540             if (i > 63){
1541                 fprintf(stderr, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1542                 return -1;
1543             }
1544
1545             mismatch^= level;
1546             block[j] = level;
1547         }
1548         CLOSE_READER(re, &s->gb);
1549     }
1550     block[63]^= mismatch&1;
1551
1552     s->block_last_index[n] = i;
1553     return 0;
1554 }
1555
1556 typedef struct Mpeg1Context {
1557     MpegEncContext mpeg_enc_ctx;
1558     int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
1559     int repeat_field; /* true if we must repeat the field */
1560 } Mpeg1Context;
1561
1562 static int mpeg_decode_init(AVCodecContext *avctx)
1563 {
1564     Mpeg1Context *s = avctx->priv_data;
1565
1566     s->mpeg_enc_ctx.flags= avctx->flags;
1567     common_init(&s->mpeg_enc_ctx);
1568     init_vlcs(&s->mpeg_enc_ctx);
1569
1570     s->mpeg_enc_ctx_allocated = 0;
1571     s->mpeg_enc_ctx.picture_number = 0;
1572     s->repeat_field = 0;
1573     s->mpeg_enc_ctx.codec_id= avctx->codec->id;
1574     return 0;
1575 }
1576
1577 /* return the 8 bit start code value and update the search
1578    state. Return -1 if no start code found */
1579 static int find_start_code(uint8_t **pbuf_ptr, uint8_t *buf_end)
1580 {
1581     uint8_t *buf_ptr;
1582     unsigned int state=0xFFFFFFFF, v;
1583     int val;
1584
1585     buf_ptr = *pbuf_ptr;
1586     while (buf_ptr < buf_end) {
1587         v = *buf_ptr++;
1588         if (state == 0x000001) {
1589             state = ((state << 8) | v) & 0xffffff;
1590             val = state;
1591             goto found;
1592         }
1593         state = ((state << 8) | v) & 0xffffff;
1594     }
1595     val = -1;
1596  found:
1597     *pbuf_ptr = buf_ptr;
1598     return val;
1599 }
1600
1601 static int mpeg1_decode_picture(AVCodecContext *avctx,
1602                                 uint8_t *buf, int buf_size)
1603 {
1604     Mpeg1Context *s1 = avctx->priv_data;
1605     MpegEncContext *s = &s1->mpeg_enc_ctx;
1606     int ref, f_code;
1607
1608     init_get_bits(&s->gb, buf, buf_size*8);
1609
1610     ref = get_bits(&s->gb, 10); /* temporal ref */
1611     s->pict_type = get_bits(&s->gb, 3);
1612     dprintf("pict_type=%d number=%d\n", s->pict_type, s->picture_number);
1613
1614     skip_bits(&s->gb, 16);
1615     if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
1616         s->full_pel[0] = get_bits1(&s->gb);
1617         f_code = get_bits(&s->gb, 3);
1618         if (f_code == 0)
1619             return -1;
1620         s->mpeg_f_code[0][0] = f_code;
1621         s->mpeg_f_code[0][1] = f_code;
1622     }
1623     if (s->pict_type == B_TYPE) {
1624         s->full_pel[1] = get_bits1(&s->gb);
1625         f_code = get_bits(&s->gb, 3);
1626         if (f_code == 0)
1627             return -1;
1628         s->mpeg_f_code[1][0] = f_code;
1629         s->mpeg_f_code[1][1] = f_code;
1630     }
1631     s->current_picture.pict_type= s->pict_type;
1632     s->current_picture.key_frame= s->pict_type == I_TYPE;
1633
1634     s->y_dc_scale = 8;
1635     s->c_dc_scale = 8;
1636     s->first_slice = 1;
1637     return 0;
1638 }
1639
1640 static void mpeg_decode_sequence_extension(MpegEncContext *s)
1641 {
1642     int horiz_size_ext, vert_size_ext;
1643     int bit_rate_ext, vbv_buf_ext;
1644     int frame_rate_ext_n, frame_rate_ext_d;
1645     float aspect;
1646
1647     skip_bits(&s->gb, 8); /* profil and level */
1648     s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */
1649     skip_bits(&s->gb, 2); /* chroma_format */
1650     horiz_size_ext = get_bits(&s->gb, 2);
1651     vert_size_ext = get_bits(&s->gb, 2);
1652     s->width |= (horiz_size_ext << 12);
1653     s->height |= (vert_size_ext << 12);
1654     bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */
1655     s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;
1656     skip_bits1(&s->gb); /* marker */
1657     vbv_buf_ext = get_bits(&s->gb, 8);
1658
1659     s->low_delay = get_bits1(&s->gb);
1660     if(s->flags & CODEC_FLAG_LOW_DELAY) s->low_delay=1;
1661
1662     frame_rate_ext_n = get_bits(&s->gb, 2);
1663     frame_rate_ext_d = get_bits(&s->gb, 5);
1664     av_reduce(
1665         &s->avctx->frame_rate,
1666         &s->avctx->frame_rate_base,
1667         frame_rate_tab[s->frame_rate_index] * (frame_rate_ext_n+1),
1668         MPEG1_FRAME_RATE_BASE * (frame_rate_ext_d+1),
1669         1<<30);
1670
1671     dprintf("sequence extension\n");
1672     s->mpeg2 = 1;
1673     s->avctx->sub_id = 2; /* indicates mpeg2 found */
1674
1675     aspect= mpeg2_aspect[s->aspect_ratio_info];
1676     if(aspect>0.0)      s->avctx->aspect_ratio= s->width/(aspect*s->height);
1677     else if(aspect<0.0) s->avctx->aspect_ratio= -1.0/aspect;
1678 }
1679
1680 static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)
1681 {
1682     int i, v, j;
1683
1684     dprintf("matrix extension\n");
1685
1686     if (get_bits1(&s->gb)) {
1687         for(i=0;i<64;i++) {
1688             v = get_bits(&s->gb, 8);
1689             j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1690             s->intra_matrix[j] = v;
1691             s->chroma_intra_matrix[j] = v;
1692         }
1693     }
1694     if (get_bits1(&s->gb)) {
1695         for(i=0;i<64;i++) {
1696             v = get_bits(&s->gb, 8);
1697             j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1698             s->inter_matrix[j] = v;
1699             s->chroma_inter_matrix[j] = v;
1700         }
1701     }
1702     if (get_bits1(&s->gb)) {
1703         for(i=0;i<64;i++) {
1704             v = get_bits(&s->gb, 8);
1705             j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1706             s->chroma_intra_matrix[j] = v;
1707         }
1708     }
1709     if (get_bits1(&s->gb)) {
1710         for(i=0;i<64;i++) {
1711             v = get_bits(&s->gb, 8);
1712             j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1713             s->chroma_inter_matrix[j] = v;
1714         }
1715     }
1716 }
1717
1718 static void mpeg_decode_picture_coding_extension(MpegEncContext *s)
1719 {
1720     s->full_pel[0] = s->full_pel[1] = 0;
1721     s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);
1722     s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);
1723     s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);
1724     s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);
1725     s->intra_dc_precision = get_bits(&s->gb, 2);
1726     s->picture_structure = get_bits(&s->gb, 2);
1727     s->top_field_first = get_bits1(&s->gb);
1728     s->frame_pred_frame_dct = get_bits1(&s->gb);
1729     s->concealment_motion_vectors = get_bits1(&s->gb);
1730     s->q_scale_type = get_bits1(&s->gb);
1731     s->intra_vlc_format = get_bits1(&s->gb);
1732     s->alternate_scan = get_bits1(&s->gb);
1733     s->repeat_first_field = get_bits1(&s->gb);
1734     s->chroma_420_type = get_bits1(&s->gb);
1735     s->progressive_frame = get_bits1(&s->gb);
1736
1737     if(s->picture_structure == PICT_FRAME)
1738         s->first_field=0;
1739     else{
1740         s->first_field ^= 1;
1741         memset(s->mbskip_table, 0, s->mb_stride*s->mb_height);
1742     }
1743
1744     if(s->alternate_scan){
1745         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_alternate_vertical_scan);
1746         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_alternate_vertical_scan);
1747         ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
1748         ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
1749     }else{
1750         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_zigzag_direct);
1751         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_zigzag_direct);
1752         ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
1753         ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
1754     }
1755
1756     /* composite display not parsed */
1757     dprintf("intra_dc_precision=%d\n", s->intra_dc_precision);
1758     dprintf("picture_structure=%d\n", s->picture_structure);
1759     dprintf("top field first=%d\n", s->top_field_first);
1760     dprintf("repeat first field=%d\n", s->repeat_first_field);
1761     dprintf("conceal=%d\n", s->concealment_motion_vectors);
1762     dprintf("intra_vlc_format=%d\n", s->intra_vlc_format);
1763     dprintf("alternate_scan=%d\n", s->alternate_scan);
1764     dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);
1765     dprintf("progressive_frame=%d\n", s->progressive_frame);
1766 }
1767
1768 static void mpeg_decode_extension(AVCodecContext *avctx,
1769                                   uint8_t *buf, int buf_size)
1770 {
1771     Mpeg1Context *s1 = avctx->priv_data;
1772     MpegEncContext *s = &s1->mpeg_enc_ctx;
1773     int ext_type;
1774
1775     init_get_bits(&s->gb, buf, buf_size*8);
1776
1777     ext_type = get_bits(&s->gb, 4);
1778     switch(ext_type) {
1779     case 0x1:
1780         /* sequence ext */
1781         mpeg_decode_sequence_extension(s);
1782         break;
1783     case 0x3:
1784         /* quant matrix extension */
1785         mpeg_decode_quant_matrix_extension(s);
1786         break;
1787     case 0x8:
1788         /* picture extension */
1789         mpeg_decode_picture_coding_extension(s);
1790         break;
1791     }
1792 }
1793
1794 #define DECODE_SLICE_FATAL_ERROR -2
1795 #define DECODE_SLICE_ERROR -1
1796 #define DECODE_SLICE_OK 0
1797
1798 /**
1799  * decodes a slice.
1800  * @return DECODE_SLICE_FATAL_ERROR if a non recoverable error occured<br>
1801  *         DECODE_SLICE_ERROR if the slice is damaged<br>
1802  *         DECODE_SLICE_OK if this slice is ok<br>
1803  */
1804 static int mpeg_decode_slice(AVCodecContext *avctx,
1805                               AVFrame *pict,
1806                               int start_code,
1807                               uint8_t **buf, int buf_size)
1808 {
1809     Mpeg1Context *s1 = avctx->priv_data;
1810     MpegEncContext *s = &s1->mpeg_enc_ctx;
1811     int ret;
1812     const int field_pic= s->picture_structure != PICT_FRAME;
1813
1814     s->resync_mb_x= s->mb_x =
1815     s->resync_mb_y= s->mb_y = -1;
1816
1817     start_code = (start_code - 1) & 0xff;
1818     if (start_code >= s->mb_height){
1819         fprintf(stderr, "slice below image (%d >= %d)\n", start_code, s->mb_height);
1820         return -1;
1821     }
1822
1823     ff_mpeg1_clean_buffers(s);
1824     s->interlaced_dct = 0;
1825
1826     /* start frame decoding */
1827     if (s->first_slice) {
1828       if(s->first_field || s->picture_structure==PICT_FRAME){
1829         if(MPV_frame_start(s, avctx) < 0)
1830             return DECODE_SLICE_FATAL_ERROR;
1831
1832         ff_er_frame_start(s);
1833
1834         /* first check if we must repeat the frame */
1835         s->current_picture.repeat_pict = 0;
1836
1837         if (s->repeat_first_field) {
1838             if (s->progressive_sequence) {
1839                 if (s->top_field_first)
1840                     s->current_picture.repeat_pict = 4;
1841                 else
1842                     s->current_picture.repeat_pict = 2;
1843             } else if (s->progressive_frame) {
1844                 s->current_picture.repeat_pict = 1;
1845             }
1846         }
1847 //        printf("%d \n", s->current_picture.repeat_pict);
1848
1849         if(s->avctx->debug&FF_DEBUG_PICT_INFO){
1850              printf("qp:%d fc:%2d%2d%2d%2d %s %s %s %s dc:%d pstruct:%d fdct:%d cmv:%d qtype:%d ivlc:%d rff:%d %s\n",
1851                  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],
1852                  s->pict_type == I_TYPE ? "I" : (s->pict_type == P_TYPE ? "P" : (s->pict_type == B_TYPE ? "B" : "S")),
1853                  s->progressive_sequence ? "pro" :"", s->alternate_scan ? "alt" :"", s->top_field_first ? "top" :"",
1854                  s->intra_dc_precision, s->picture_structure, s->frame_pred_frame_dct, s->concealment_motion_vectors,
1855                  s->q_scale_type, s->intra_vlc_format, s->repeat_first_field, s->chroma_420_type ? "420" :"");
1856         }
1857       }else{ //second field
1858             int i;
1859
1860             if(!s->current_picture_ptr){
1861                 fprintf(stderr, "first field missing\n");
1862                 return -1;
1863             }
1864
1865             for(i=0; i<4; i++){
1866                 s->current_picture.data[i] = s->current_picture_ptr->data[i];
1867                 if(s->picture_structure == PICT_BOTTOM_FIELD){
1868                     s->current_picture.data[i] += s->current_picture_ptr->linesize[i];
1869                 }
1870             }
1871       }
1872     }
1873     s->first_slice = 0;
1874
1875     init_get_bits(&s->gb, *buf, buf_size*8);
1876
1877     s->qscale = get_qscale(s);
1878     if(s->qscale == 0){
1879         fprintf(stderr, "qscale == 0\n");
1880         return -1;
1881     }
1882
1883     /* extra slice info */
1884     while (get_bits1(&s->gb) != 0) {
1885         skip_bits(&s->gb, 8);
1886     }
1887
1888     s->mb_x=0;
1889
1890     for(;;) {
1891         int code = get_vlc2(&s->gb, mbincr_vlc.table, MBINCR_VLC_BITS, 2);
1892         if (code < 0){
1893             fprintf(stderr, "first mb_incr damaged\n");
1894             return -1;
1895         }
1896         if (code >= 33) {
1897             if (code == 33) {
1898                 s->mb_x += 33;
1899             }
1900             /* otherwise, stuffing, nothing to do */
1901         } else {
1902             s->mb_x += code;
1903             break;
1904         }
1905     }
1906
1907     s->resync_mb_x= s->mb_x;
1908     s->resync_mb_y= s->mb_y = start_code;
1909     s->mb_skip_run= 0;
1910
1911     for(;;) {
1912         s->dsp.clear_blocks(s->block[0]);
1913
1914         ret = mpeg_decode_mb(s, s->block);
1915
1916         dprintf("ret=%d\n", ret);
1917         if (ret < 0)
1918             return -1;
1919
1920         if(s->motion_val && s->pict_type != B_TYPE){ //note motion_val is normally NULL unless we want to extract the MVs
1921             const int wrap = s->block_wrap[0];
1922             const int xy = s->mb_x*2 + 1 + (s->mb_y*2 +1)*wrap;
1923             int motion_x, motion_y;
1924
1925             if (s->mb_intra) {
1926                 motion_x = motion_y = 0;
1927             }else if (s->mv_type == MV_TYPE_16X16) {
1928                 motion_x = s->mv[0][0][0];
1929                 motion_y = s->mv[0][0][1];
1930             } else /*if (s->mv_type == MV_TYPE_FIELD)*/ {
1931                 motion_x = s->mv[0][0][0] + s->mv[0][1][0];
1932                 motion_y = s->mv[0][0][1] + s->mv[0][1][1];
1933                 motion_x = (motion_x>>1) | (motion_x&1);
1934             }
1935             s->motion_val[xy][0] = motion_x;
1936             s->motion_val[xy][1] = motion_y;
1937             s->motion_val[xy + 1][0] = motion_x;
1938             s->motion_val[xy + 1][1] = motion_y;
1939             s->motion_val[xy + wrap][0] = motion_x;
1940             s->motion_val[xy + wrap][1] = motion_y;
1941             s->motion_val[xy + 1 + wrap][0] = motion_x;
1942             s->motion_val[xy + 1 + wrap][1] = motion_y;
1943         }
1944
1945         MPV_decode_mb(s, s->block);
1946
1947         if (++s->mb_x >= s->mb_width) {
1948             ff_draw_horiz_band(s, 16*s->mb_y, 16);
1949
1950             s->mb_x = 0;
1951             s->mb_y++;
1952
1953             if(s->mb_y<<field_pic >= s->mb_height){
1954                 int left= s->gb.size_in_bits - get_bits_count(&s->gb);
1955
1956                 if(left < 0 || (left && show_bits(&s->gb, FFMIN(left, 23)))
1957                    || (avctx->error_resilience >= FF_ER_AGGRESSIVE && left>8)){
1958                     fprintf(stderr, "end missmatch left=%d\n", left);
1959                     return -1;
1960                 }else
1961                     goto eos;
1962             }
1963         }
1964
1965         /* skip mb handling */
1966         if (s->mb_skip_run == -1) {
1967             /* read again increment */
1968             s->mb_skip_run = 0;
1969             for(;;) {
1970                 int code = get_vlc2(&s->gb, mbincr_vlc.table, MBINCR_VLC_BITS, 2);
1971                 if (code < 0){
1972                     fprintf(stderr, "mb incr damaged\n");
1973                     return -1;
1974                 }
1975                 if (code >= 33) {
1976                     if (code == 33) {
1977                         s->mb_skip_run += 33;
1978                     }else if(code == 35){
1979                         if(s->mb_skip_run != 0 || show_bits(&s->gb, 15) != 0){
1980                             fprintf(stderr, "slice missmatch\n");
1981                             return -1;
1982                         }
1983                         goto eos; /* end of slice */
1984                     }
1985                     /* otherwise, stuffing, nothing to do */
1986                 } else {
1987                     s->mb_skip_run += code;
1988                     break;
1989                 }
1990             }
1991         }
1992     }
1993 eos: // end of slice
1994     *buf += get_bits_count(&s->gb)/8 - 1;
1995 //printf("y %d %d %d %d\n", s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y);
1996     return 0;
1997 }
1998
1999 /**
2000  * handles slice ends.
2001  * @return 1 if it seems to be the last slice of
2002  */
2003 static int slice_end(AVCodecContext *avctx, AVFrame *pict)
2004 {
2005     Mpeg1Context *s1 = avctx->priv_data;
2006     MpegEncContext *s = &s1->mpeg_enc_ctx;
2007
2008     if (!s1->mpeg_enc_ctx_allocated)
2009         return 0;
2010
2011     /* end of slice reached */
2012     if (/*s->mb_y<<field_pic == s->mb_height &&*/ !s->first_field) {
2013         /* end of image */
2014
2015         if(s->mpeg2){
2016             s->current_picture_ptr->qscale_type= FF_QSCALE_TYPE_MPEG2;
2017         }else
2018             s->current_picture_ptr->qscale_type= FF_QSCALE_TYPE_MPEG1;
2019
2020         ff_er_frame_end(s);
2021
2022         MPV_frame_end(s);
2023
2024         if (s->pict_type == B_TYPE || s->low_delay) {
2025             *pict= *(AVFrame*)s->current_picture_ptr;
2026             ff_print_debug_info(s, s->current_picture_ptr);
2027         } else {
2028             s->picture_number++;
2029             /* latency of 1 frame for I and P frames */
2030             /* XXX: use another variable than picture_number */
2031             if (s->last_picture_ptr != NULL) {
2032                 *pict= *(AVFrame*)s->last_picture_ptr;
2033                  ff_print_debug_info(s, s->last_picture_ptr);
2034             }
2035         }
2036         return 1;
2037     } else {
2038         return 0;
2039     }
2040 }
2041
2042 static int mpeg1_decode_sequence(AVCodecContext *avctx,
2043                                  uint8_t *buf, int buf_size)
2044 {
2045     Mpeg1Context *s1 = avctx->priv_data;
2046     MpegEncContext *s = &s1->mpeg_enc_ctx;
2047     int width, height, i, v, j;
2048     float aspect;
2049
2050     init_get_bits(&s->gb, buf, buf_size*8);
2051
2052     width = get_bits(&s->gb, 12);
2053     height = get_bits(&s->gb, 12);
2054     s->aspect_ratio_info= get_bits(&s->gb, 4);
2055     if(!s->mpeg2){
2056         aspect= mpeg1_aspect[s->aspect_ratio_info];
2057         if(aspect!=0.0) avctx->aspect_ratio= width/(aspect*height);
2058     }
2059
2060     s->frame_rate_index = get_bits(&s->gb, 4);
2061     if (s->frame_rate_index == 0)
2062         return -1;
2063     s->bit_rate = get_bits(&s->gb, 18) * 400;
2064     if (get_bits1(&s->gb) == 0) /* marker */
2065         return -1;
2066     if (width <= 0 || height <= 0 ||
2067         (width % 2) != 0 || (height % 2) != 0)
2068         return -1;
2069     if (width != s->width ||
2070         height != s->height) {
2071         /* start new mpeg1 context decoding */
2072         s->out_format = FMT_MPEG1;
2073         if (s1->mpeg_enc_ctx_allocated) {
2074             MPV_common_end(s);
2075         }
2076         s->width = width;
2077         s->height = height;
2078         avctx->has_b_frames= 1;
2079         s->avctx = avctx;
2080         avctx->width = width;
2081         avctx->height = height;
2082         av_reduce(
2083             &avctx->frame_rate,
2084             &avctx->frame_rate_base,
2085             frame_rate_tab[s->frame_rate_index],
2086             MPEG1_FRAME_RATE_BASE, //FIXME store in allready reduced form
2087             1<<30
2088             );
2089         avctx->bit_rate = s->bit_rate;
2090
2091         if (MPV_common_init(s) < 0)
2092             return -1;
2093         s1->mpeg_enc_ctx_allocated = 1;
2094     }
2095
2096     skip_bits(&s->gb, 10); /* vbv_buffer_size */
2097     skip_bits(&s->gb, 1);
2098
2099     /* get matrix */
2100     if (get_bits1(&s->gb)) {
2101         for(i=0;i<64;i++) {
2102             v = get_bits(&s->gb, 8);
2103             j = s->intra_scantable.permutated[i];
2104             s->intra_matrix[j] = v;
2105             s->chroma_intra_matrix[j] = v;
2106         }
2107 #ifdef DEBUG
2108         dprintf("intra matrix present\n");
2109         for(i=0;i<64;i++)
2110             dprintf(" %d", s->intra_matrix[s->intra_scantable.permutated[i]]);
2111         printf("\n");
2112 #endif
2113     } else {
2114         for(i=0;i<64;i++) {
2115             int j= s->dsp.idct_permutation[i];
2116             v = ff_mpeg1_default_intra_matrix[i];
2117             s->intra_matrix[j] = v;
2118             s->chroma_intra_matrix[j] = v;
2119         }
2120     }
2121     if (get_bits1(&s->gb)) {
2122         for(i=0;i<64;i++) {
2123             v = get_bits(&s->gb, 8);
2124             j = s->intra_scantable.permutated[i];
2125             s->inter_matrix[j] = v;
2126             s->chroma_inter_matrix[j] = v;
2127         }
2128 #ifdef DEBUG
2129         dprintf("non intra matrix present\n");
2130         for(i=0;i<64;i++)
2131             dprintf(" %d", s->inter_matrix[s->intra_scantable.permutated[i]]);
2132         printf("\n");
2133 #endif
2134     } else {
2135         for(i=0;i<64;i++) {
2136             int j= s->dsp.idct_permutation[i];
2137             v = ff_mpeg1_default_non_intra_matrix[i];
2138             s->inter_matrix[j] = v;
2139             s->chroma_inter_matrix[j] = v;
2140         }
2141     }
2142
2143     /* we set mpeg2 parameters so that it emulates mpeg1 */
2144     s->progressive_sequence = 1;
2145     s->progressive_frame = 1;
2146     s->picture_structure = PICT_FRAME;
2147     s->frame_pred_frame_dct = 1;
2148     s->mpeg2 = 0;
2149     avctx->sub_id = 1; /* indicates mpeg1 */
2150     return 0;
2151 }
2152
2153 static int vcr2_init_sequence(AVCodecContext *avctx)
2154 {
2155     Mpeg1Context *s1 = avctx->priv_data;
2156     MpegEncContext *s = &s1->mpeg_enc_ctx;
2157     int i, v, j;
2158     float aspect;
2159
2160     /* start new mpeg1 context decoding */
2161     s->out_format = FMT_MPEG1;
2162     if (s1->mpeg_enc_ctx_allocated) {
2163         MPV_common_end(s);
2164     }
2165     s->width = avctx->width;
2166     s->height = avctx->height;
2167     avctx->has_b_frames= 0; //true?
2168     s->avctx = avctx;
2169
2170     if (MPV_common_init(s) < 0)
2171         return -1;
2172     s1->mpeg_enc_ctx_allocated = 1;
2173
2174     for(i=0;i<64;i++) {
2175         int j= s->dsp.idct_permutation[i];
2176         v = ff_mpeg1_default_intra_matrix[i];
2177         s->intra_matrix[j] = v;
2178         s->chroma_intra_matrix[j] = v;
2179
2180         v = ff_mpeg1_default_non_intra_matrix[i];
2181         s->inter_matrix[j] = v;
2182         s->chroma_inter_matrix[j] = v;
2183     }
2184
2185     /* we set mpeg2 parameters so that it emulates mpeg1 */
2186     s->progressive_sequence = 1;
2187     s->progressive_frame = 1;
2188     s->picture_structure = PICT_FRAME;
2189     s->frame_pred_frame_dct = 1;
2190     s->mpeg2 = 1;
2191     avctx->sub_id = 2; /* indicates mpeg1 */
2192     return 0;
2193 }
2194
2195
2196 static void mpeg_decode_user_data(AVCodecContext *avctx,
2197                                   const uint8_t *buf, int buf_size)
2198 {
2199     const uint8_t *p;
2200     int len, flags;
2201     p = buf;
2202     len = buf_size;
2203
2204     /* we parse the DTG active format information */
2205     if (len >= 5 &&
2206         p[0] == 'D' && p[1] == 'T' && p[2] == 'G' && p[3] == '1') {
2207         flags = p[4];
2208         p += 5;
2209         len -= 5;
2210         if (flags & 0x80) {
2211             /* skip event id */
2212             if (len < 2)
2213                 return;
2214             p += 2;
2215             len -= 2;
2216         }
2217         if (flags & 0x40) {
2218             if (len < 1)
2219                 return;
2220             avctx->dtg_active_format = p[0] & 0x0f;
2221         }
2222     }
2223 }
2224
2225 /**
2226  * finds the end of the current frame in the bitstream.
2227  * @return the position of the first byte of the next frame, or -1
2228  */
2229 static int mpeg1_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
2230     ParseContext *pc= &s->parse_context;
2231     int i;
2232     uint32_t state;
2233
2234     state= pc->state;
2235
2236     i=0;
2237     if(!pc->frame_start_found){
2238         for(i=0; i<buf_size; i++){
2239             state= (state<<8) | buf[i];
2240             if(state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE){
2241                 i++;
2242                 pc->frame_start_found=1;
2243                 break;
2244             }
2245         }
2246     }
2247
2248     if(pc->frame_start_found){
2249         for(; i<buf_size; i++){
2250             state= (state<<8) | buf[i];
2251             if((state&0xFFFFFF00) == 0x100){
2252                 if(state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE){
2253                     pc->frame_start_found=0;
2254                     pc->state=-1;
2255                     return i-3;
2256                 }
2257             }
2258         }
2259     }
2260     pc->state= state;
2261     return END_NOT_FOUND;
2262 }
2263
2264 /* handle buffering and image synchronisation */
2265 static int mpeg_decode_frame(AVCodecContext *avctx,
2266                              void *data, int *data_size,
2267                              uint8_t *buf, int buf_size)
2268 {
2269     Mpeg1Context *s = avctx->priv_data;
2270     uint8_t *buf_end, *buf_ptr;
2271     int ret, start_code, input_size;
2272     AVFrame *picture = data;
2273     MpegEncContext *s2 = &s->mpeg_enc_ctx;
2274     dprintf("fill_buffer\n");
2275
2276     *data_size = 0;
2277
2278     /* special case for last picture */
2279     if (buf_size == 0 && s2->low_delay==0 && s2->next_picture_ptr) {
2280         *picture= *(AVFrame*)s2->next_picture_ptr;
2281         s2->next_picture_ptr= NULL;
2282
2283         *data_size = sizeof(AVFrame);
2284         return 0;
2285     }
2286
2287     if(s2->flags&CODEC_FLAG_TRUNCATED){
2288         int next= mpeg1_find_frame_end(s2, buf, buf_size);
2289
2290         if( ff_combine_frame(s2, next, &buf, &buf_size) < 0 )
2291             return buf_size;
2292     }
2293
2294     buf_ptr = buf;
2295     buf_end = buf + buf_size;
2296
2297 #if 0
2298     if (s->repeat_field % 2 == 1) {
2299         s->repeat_field++;
2300         //fprintf(stderr,"\nRepeating last frame: %d -> %d! pict: %d %d", avctx->frame_number-1, avctx->frame_number,
2301         //        s2->picture_number, s->repeat_field);
2302         if (avctx->flags & CODEC_FLAG_REPEAT_FIELD) {
2303             *data_size = sizeof(AVPicture);
2304             goto the_end;
2305         }
2306     }
2307 #endif
2308
2309     if(s->mpeg_enc_ctx_allocated==0 && avctx->codec_tag == ff_get_fourcc("VCR2"))
2310         vcr2_init_sequence(avctx);
2311
2312     for(;;) {
2313         /* find start next code */
2314         start_code = find_start_code(&buf_ptr, buf_end);
2315         if (start_code < 0){
2316             if (slice_end(avctx, picture)) {
2317                 if(s2->last_picture_ptr) //FIXME merge with the stuff in mpeg_decode_slice
2318                     *data_size = sizeof(AVPicture);
2319             }
2320             return FFMAX(0, buf_ptr - buf - s2->parse_context.last_index);
2321         }
2322
2323         input_size = buf_end - buf_ptr;
2324
2325         if(avctx->debug & FF_DEBUG_STARTCODE){
2326             printf("%3X at %d left %d\n", start_code, buf_ptr-buf, input_size);
2327         }
2328
2329                 /* prepare data for next start code */
2330                 switch(start_code) {
2331                 case SEQ_START_CODE:
2332                     mpeg1_decode_sequence(avctx, buf_ptr,
2333                                           input_size);
2334                     break;
2335
2336                 case PICTURE_START_CODE:
2337                     /* we have a complete image : we try to decompress it */
2338                     mpeg1_decode_picture(avctx,
2339                                          buf_ptr, input_size);
2340                     break;
2341                 case EXT_START_CODE:
2342                     mpeg_decode_extension(avctx,
2343                                           buf_ptr, input_size);
2344                     break;
2345                 case USER_START_CODE:
2346                     mpeg_decode_user_data(avctx,
2347                                           buf_ptr, input_size);
2348                     break;
2349                 case GOP_START_CODE:
2350                     s2->first_field=0;
2351                     break;
2352                 default:
2353                     if (start_code >= SLICE_MIN_START_CODE &&
2354                         start_code <= SLICE_MAX_START_CODE) {
2355
2356                         /* skip b frames if we dont have reference frames */
2357                         if(s2->last_picture_ptr==NULL && s2->pict_type==B_TYPE) break;
2358                         /* skip b frames if we are in a hurry */
2359                         if(avctx->hurry_up && s2->pict_type==B_TYPE) break;
2360                         /* skip everything if we are in a hurry>=5 */
2361                         if(avctx->hurry_up>=5) break;
2362
2363                         if (!s->mpeg_enc_ctx_allocated) break;
2364
2365                         ret = mpeg_decode_slice(avctx, picture,
2366                                                 start_code, &buf_ptr, input_size);
2367                         emms_c();
2368
2369                         if(ret < 0){
2370                             if(s2->resync_mb_x>=0 && s2->resync_mb_y>=0)
2371                                 ff_er_add_slice(s2, s2->resync_mb_x, s2->resync_mb_y, s2->mb_x, s2->mb_y, AC_ERROR|DC_ERROR|MV_ERROR);
2372                             if(ret==DECODE_SLICE_FATAL_ERROR) return -1;
2373                         }else{
2374                             ff_er_add_slice(s2, s2->resync_mb_x, s2->resync_mb_y, s2->mb_x-1, s2->mb_y, AC_END|DC_END|MV_END);
2375                         }
2376                     }
2377                     break;
2378                 }
2379     }
2380 }
2381
2382 static int mpeg_decode_end(AVCodecContext *avctx)
2383 {
2384     Mpeg1Context *s = avctx->priv_data;
2385
2386     if (s->mpeg_enc_ctx_allocated)
2387         MPV_common_end(&s->mpeg_enc_ctx);
2388     return 0;
2389 }
2390
2391 AVCodec mpeg_decoder = {
2392     "mpegvideo",
2393     CODEC_TYPE_VIDEO,
2394     CODEC_ID_MPEG1VIDEO,
2395     sizeof(Mpeg1Context),
2396     mpeg_decode_init,
2397     NULL,
2398     mpeg_decode_end,
2399     mpeg_decode_frame,
2400     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED,
2401     .flush= ff_mpeg_flush,
2402 };