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   1 /*
   2  * MPEG4 decoder.
   3  * Copyright (c) 2000,2001 Fabrice Bellard
   4  * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
   5  *
   6  * This file is part of Libav.
   7  *
   8  * Libav is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * Libav is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with Libav; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "mpegvideo.h"
  24 #include "mpeg4video.h"
  25 #include "h263.h"
  26
  27 // The defines below define the number of bits that are read at once for
  28 // reading vlc values. Changing these may improve speed and data cache needs
  29 // be aware though that decreasing them may need the number of stages that is
  30 // passed to get_vlc* to be increased.
  31 #define SPRITE_TRAJ_VLC_BITS 6
  32 #define DC_VLC_BITS 9
  33 #define MB_TYPE_B_VLC_BITS 4
  34
  35
  36 static VLC dc_lum, dc_chrom;
  37 static VLC sprite_trajectory;
  38 static VLC mb_type_b_vlc;
  39
  40 static const int mb_type_b_map[4]= {
  41     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
  42     MB_TYPE_L0L1 | MB_TYPE_16x16,
  43     MB_TYPE_L1 | MB_TYPE_16x16,
  44     MB_TYPE_L0 | MB_TYPE_16x16,
  45 };
  46
  47 /**
  48  * predicts the ac.
  49  * @param n block index (0-3 are luma, 4-5 are chroma)
  50  * @param dir the ac prediction direction
  51  */
  52 void mpeg4_pred_ac(MpegEncContext * s, DCTELEM *block, int n,
  53                    int dir)
  54 {
  55     int i;
  56     int16_t *ac_val, *ac_val1;
  57     int8_t * const qscale_table= s->current_picture.qscale_table;
  58
  59     /* find prediction */
  60     ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
  61     ac_val1 = ac_val;
  62     if (s->ac_pred) {
  63         if (dir == 0) {
  64             const int xy= s->mb_x-1 + s->mb_y*s->mb_stride;
  65             /* left prediction */
  66             ac_val -= 16;
  67
  68             if(s->mb_x==0 || s->qscale == qscale_table[xy] || n==1 || n==3){
  69                 /* same qscale */
  70                 for(i=1;i<8;i++) {
  71                     block[s->dsp.idct_permutation[i<<3]] += ac_val[i];
  72                 }
  73             }else{
  74                 /* different qscale, we must rescale */
  75                 for(i=1;i<8;i++) {
  76                     block[s->dsp.idct_permutation[i<<3]] += ROUNDED_DIV(ac_val[i]*qscale_table[xy], s->qscale);
  77                 }
  78             }
  79         } else {
  80             const int xy= s->mb_x + s->mb_y*s->mb_stride - s->mb_stride;
  81             /* top prediction */
  82             ac_val -= 16 * s->block_wrap[n];
  83
  84             if(s->mb_y==0 || s->qscale == qscale_table[xy] || n==2 || n==3){
  85                 /* same qscale */
  86                 for(i=1;i<8;i++) {
  87                     block[s->dsp.idct_permutation[i]] += ac_val[i + 8];
  88                 }
  89             }else{
  90                 /* different qscale, we must rescale */
  91                 for(i=1;i<8;i++) {
  92                     block[s->dsp.idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8]*qscale_table[xy], s->qscale);
  93                 }
  94             }
  95         }
  96     }
  97     /* left copy */
  98     for(i=1;i<8;i++)
  99         ac_val1[i    ] = block[s->dsp.idct_permutation[i<<3]];
 100
 101     /* top copy */
 102     for(i=1;i<8;i++)
 103         ac_val1[8 + i] = block[s->dsp.idct_permutation[i   ]];
 104
 105 }
 106
 107 /**
 108  * check if the next stuff is a resync marker or the end.
 109  * @return 0 if not
 110  */
 111 static inline int mpeg4_is_resync(MpegEncContext *s){
 112     int bits_count= get_bits_count(&s->gb);
 113     int v= show_bits(&s->gb, 16);
 114
 115     if(s->workaround_bugs&FF_BUG_NO_PADDING){
 116         return 0;
 117     }
 118
 119     while(v<=0xFF){
 120         if(s->pict_type==FF_B_TYPE || (v>>(8-s->pict_type)!=1) || s->partitioned_frame)
 121             break;
 122         skip_bits(&s->gb, 8+s->pict_type);
 123         bits_count+= 8+s->pict_type;
 124         v= show_bits(&s->gb, 16);
 125     }
 126
 127     if(bits_count + 8 >= s->gb.size_in_bits){
 128         v>>=8;
 129         v|= 0x7F >> (7-(bits_count&7));
 130
 131         if(v==0x7F)
 132             return 1;
 133     }else{
 134         if(v == ff_mpeg4_resync_prefix[bits_count&7]){
 135             int len;
 136             GetBitContext gb= s->gb;
 137
 138             skip_bits(&s->gb, 1);
 139             align_get_bits(&s->gb);
 140
 141             for(len=0; len<32; len++){
 142                 if(get_bits1(&s->gb)) break;
 143             }
 144
 145             s->gb= gb;
 146
 147             if(len>=ff_mpeg4_get_video_packet_prefix_length(s))
 148                 return 1;
 149         }
 150     }
 151     return 0;
 152 }
 153
 154 static void mpeg4_decode_sprite_trajectory(MpegEncContext * s, GetBitContext *gb)
 155 {
 156     int i;
 157     int a= 2<<s->sprite_warping_accuracy;
 158     int rho= 3-s->sprite_warping_accuracy;
 159     int r=16/a;
 160     const int vop_ref[4][2]= {{0,0}, {s->width,0}, {0, s->height}, {s->width, s->height}}; // only true for rectangle shapes
 161     int d[4][2]={{0,0}, {0,0}, {0,0}, {0,0}};
 162     int sprite_ref[4][2];
 163     int virtual_ref[2][2];
 164     int w2, h2, w3, h3;
 165     int alpha=0, beta=0;
 166     int w= s->width;
 167     int h= s->height;
 168     int min_ab;
 169
 170     for(i=0; i<s->num_sprite_warping_points; i++){
 171         int length;
 172         int x=0, y=0;
 173
 174         length= get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 175         if(length){
 176             x= get_xbits(gb, length);
 177         }
 178         if(!(s->divx_version==500 && s->divx_build==413)) skip_bits1(gb); /* marker bit */
 179
 180         length= get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 181         if(length){
 182             y=get_xbits(gb, length);
 183         }
 184         skip_bits1(gb); /* marker bit */
 185         s->sprite_traj[i][0]= d[i][0]= x;
 186         s->sprite_traj[i][1]= d[i][1]= y;
 187     }
 188     for(; i<4; i++)
 189         s->sprite_traj[i][0]= s->sprite_traj[i][1]= 0;
 190
 191     while((1<<alpha)<w) alpha++;
 192     while((1<<beta )<h) beta++; // there seems to be a typo in the mpeg4 std for the definition of w' and h'
 193     w2= 1<<alpha;
 194     h2= 1<<beta;
 195
 196 // Note, the 4th point isn't used for GMC
 197     if(s->divx_version==500 && s->divx_build==413){
 198         sprite_ref[0][0]= a*vop_ref[0][0] + d[0][0];
 199         sprite_ref[0][1]= a*vop_ref[0][1] + d[0][1];
 200         sprite_ref[1][0]= a*vop_ref[1][0] + d[0][0] + d[1][0];
 201         sprite_ref[1][1]= a*vop_ref[1][1] + d[0][1] + d[1][1];
 202         sprite_ref[2][0]= a*vop_ref[2][0] + d[0][0] + d[2][0];
 203         sprite_ref[2][1]= a*vop_ref[2][1] + d[0][1] + d[2][1];
 204     } else {
 205         sprite_ref[0][0]= (a>>1)*(2*vop_ref[0][0] + d[0][0]);
 206         sprite_ref[0][1]= (a>>1)*(2*vop_ref[0][1] + d[0][1]);
 207         sprite_ref[1][0]= (a>>1)*(2*vop_ref[1][0] + d[0][0] + d[1][0]);
 208         sprite_ref[1][1]= (a>>1)*(2*vop_ref[1][1] + d[0][1] + d[1][1]);
 209         sprite_ref[2][0]= (a>>1)*(2*vop_ref[2][0] + d[0][0] + d[2][0]);
 210         sprite_ref[2][1]= (a>>1)*(2*vop_ref[2][1] + d[0][1] + d[2][1]);
 211     }
 212 /*    sprite_ref[3][0]= (a>>1)*(2*vop_ref[3][0] + d[0][0] + d[1][0] + d[2][0] + d[3][0]);
 213     sprite_ref[3][1]= (a>>1)*(2*vop_ref[3][1] + d[0][1] + d[1][1] + d[2][1] + d[3][1]); */
 214
 215 // this is mostly identical to the mpeg4 std (and is totally unreadable because of that ...)
 216 // perhaps it should be reordered to be more readable ...
 217 // the idea behind this virtual_ref mess is to be able to use shifts later per pixel instead of divides
 218 // so the distance between points is converted from w&h based to w2&h2 based which are of the 2^x form
 219     virtual_ref[0][0]= 16*(vop_ref[0][0] + w2)
 220         + ROUNDED_DIV(((w - w2)*(r*sprite_ref[0][0] - 16*vop_ref[0][0]) + w2*(r*sprite_ref[1][0] - 16*vop_ref[1][0])),w);
 221     virtual_ref[0][1]= 16*vop_ref[0][1]
 222         + ROUNDED_DIV(((w - w2)*(r*sprite_ref[0][1] - 16*vop_ref[0][1]) + w2*(r*sprite_ref[1][1] - 16*vop_ref[1][1])),w);
 223     virtual_ref[1][0]= 16*vop_ref[0][0]
 224         + ROUNDED_DIV(((h - h2)*(r*sprite_ref[0][0] - 16*vop_ref[0][0]) + h2*(r*sprite_ref[2][0] - 16*vop_ref[2][0])),h);
 225     virtual_ref[1][1]= 16*(vop_ref[0][1] + h2)
 226         + ROUNDED_DIV(((h - h2)*(r*sprite_ref[0][1] - 16*vop_ref[0][1]) + h2*(r*sprite_ref[2][1] - 16*vop_ref[2][1])),h);
 227
 228     switch(s->num_sprite_warping_points)
 229     {
 230         case 0:
 231             s->sprite_offset[0][0]= 0;
 232             s->sprite_offset[0][1]= 0;
 233             s->sprite_offset[1][0]= 0;
 234             s->sprite_offset[1][1]= 0;
 235             s->sprite_delta[0][0]= a;
 236             s->sprite_delta[0][1]= 0;
 237             s->sprite_delta[1][0]= 0;
 238             s->sprite_delta[1][1]= a;
 239             s->sprite_shift[0]= 0;
 240             s->sprite_shift[1]= 0;
 241             break;
 242         case 1: //GMC only
 243             s->sprite_offset[0][0]= sprite_ref[0][0] - a*vop_ref[0][0];
 244             s->sprite_offset[0][1]= sprite_ref[0][1] - a*vop_ref[0][1];
 245             s->sprite_offset[1][0]= ((sprite_ref[0][0]>>1)|(sprite_ref[0][0]&1)) - a*(vop_ref[0][0]/2);
 246             s->sprite_offset[1][1]= ((sprite_ref[0][1]>>1)|(sprite_ref[0][1]&1)) - a*(vop_ref[0][1]/2);
 247             s->sprite_delta[0][0]= a;
 248             s->sprite_delta[0][1]= 0;
 249             s->sprite_delta[1][0]= 0;
 250             s->sprite_delta[1][1]= a;
 251             s->sprite_shift[0]= 0;
 252             s->sprite_shift[1]= 0;
 253             break;
 254         case 2:
 255             s->sprite_offset[0][0]= (sprite_ref[0][0]<<(alpha+rho))
 256                                                   + (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-vop_ref[0][0])
 257                                                   + ( r*sprite_ref[0][1] - virtual_ref[0][1])*(-vop_ref[0][1])
 258                                                   + (1<<(alpha+rho-1));
 259             s->sprite_offset[0][1]= (sprite_ref[0][1]<<(alpha+rho))
 260                                                   + (-r*sprite_ref[0][1] + virtual_ref[0][1])*(-vop_ref[0][0])
 261                                                   + (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-vop_ref[0][1])
 262                                                   + (1<<(alpha+rho-1));
 263             s->sprite_offset[1][0]= ( (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-2*vop_ref[0][0] + 1)
 264                                      +( r*sprite_ref[0][1] - virtual_ref[0][1])*(-2*vop_ref[0][1] + 1)
 265                                      +2*w2*r*sprite_ref[0][0]
 266                                      - 16*w2
 267                                      + (1<<(alpha+rho+1)));
 268             s->sprite_offset[1][1]= ( (-r*sprite_ref[0][1] + virtual_ref[0][1])*(-2*vop_ref[0][0] + 1)
 269                                      +(-r*sprite_ref[0][0] + virtual_ref[0][0])*(-2*vop_ref[0][1] + 1)
 270                                      +2*w2*r*sprite_ref[0][1]
 271                                      - 16*w2
 272                                      + (1<<(alpha+rho+1)));
 273             s->sprite_delta[0][0]=   (-r*sprite_ref[0][0] + virtual_ref[0][0]);
 274             s->sprite_delta[0][1]=   (+r*sprite_ref[0][1] - virtual_ref[0][1]);
 275             s->sprite_delta[1][0]=   (-r*sprite_ref[0][1] + virtual_ref[0][1]);
 276             s->sprite_delta[1][1]=   (-r*sprite_ref[0][0] + virtual_ref[0][0]);
 277
 278             s->sprite_shift[0]= alpha+rho;
 279             s->sprite_shift[1]= alpha+rho+2;
 280             break;
 281         case 3:
 282             min_ab= FFMIN(alpha, beta);
 283             w3= w2>>min_ab;
 284             h3= h2>>min_ab;
 285             s->sprite_offset[0][0]=  (sprite_ref[0][0]<<(alpha+beta+rho-min_ab))
 286                                    + (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3*(-vop_ref[0][0])
 287                                    + (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3*(-vop_ref[0][1])
 288                                    + (1<<(alpha+beta+rho-min_ab-1));
 289             s->sprite_offset[0][1]=  (sprite_ref[0][1]<<(alpha+beta+rho-min_ab))
 290                                    + (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3*(-vop_ref[0][0])
 291                                    + (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3*(-vop_ref[0][1])
 292                                    + (1<<(alpha+beta+rho-min_ab-1));
 293             s->sprite_offset[1][0]=  (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3*(-2*vop_ref[0][0] + 1)
 294                                    + (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3*(-2*vop_ref[0][1] + 1)
 295                                    + 2*w2*h3*r*sprite_ref[0][0]
 296                                    - 16*w2*h3
 297                                    + (1<<(alpha+beta+rho-min_ab+1));
 298             s->sprite_offset[1][1]=  (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3*(-2*vop_ref[0][0] + 1)
 299                                    + (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3*(-2*vop_ref[0][1] + 1)
 300                                    + 2*w2*h3*r*sprite_ref[0][1]
 301                                    - 16*w2*h3
 302                                    + (1<<(alpha+beta+rho-min_ab+1));
 303             s->sprite_delta[0][0]=   (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3;
 304             s->sprite_delta[0][1]=   (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3;
 305             s->sprite_delta[1][0]=   (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3;
 306             s->sprite_delta[1][1]=   (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3;
 307
 308             s->sprite_shift[0]= alpha + beta + rho - min_ab;
 309             s->sprite_shift[1]= alpha + beta + rho - min_ab + 2;
 310             break;
 311     }
 312     /* try to simplify the situation */
 313     if(   s->sprite_delta[0][0] == a<<s->sprite_shift[0]
 314        && s->sprite_delta[0][1] == 0
 315        && s->sprite_delta[1][0] == 0
 316        && s->sprite_delta[1][1] == a<<s->sprite_shift[0])
 317     {
 318         s->sprite_offset[0][0]>>=s->sprite_shift[0];
 319         s->sprite_offset[0][1]>>=s->sprite_shift[0];
 320         s->sprite_offset[1][0]>>=s->sprite_shift[1];
 321         s->sprite_offset[1][1]>>=s->sprite_shift[1];
 322         s->sprite_delta[0][0]= a;
 323         s->sprite_delta[0][1]= 0;
 324         s->sprite_delta[1][0]= 0;
 325         s->sprite_delta[1][1]= a;
 326         s->sprite_shift[0]= 0;
 327         s->sprite_shift[1]= 0;
 328         s->real_sprite_warping_points=1;
 329     }
 330     else{
 331         int shift_y= 16 - s->sprite_shift[0];
 332         int shift_c= 16 - s->sprite_shift[1];
 333         for(i=0; i<2; i++){
 334             s->sprite_offset[0][i]<<= shift_y;
 335             s->sprite_offset[1][i]<<= shift_c;
 336             s->sprite_delta[0][i]<<= shift_y;
 337             s->sprite_delta[1][i]<<= shift_y;
 338             s->sprite_shift[i]= 16;
 339         }
 340         s->real_sprite_warping_points= s->num_sprite_warping_points;
 341     }
 342 }
 343
 344 /**
 345  * decodes the next video packet.
 346  * @return <0 if something went wrong
 347  */
 348 int mpeg4_decode_video_packet_header(MpegEncContext *s)
 349 {
 350     int mb_num_bits= av_log2(s->mb_num - 1) + 1;
 351     int header_extension=0, mb_num, len;
 352
 353     /* is there enough space left for a video packet + header */
 354     if( get_bits_count(&s->gb) > s->gb.size_in_bits-20) return -1;
 355
 356     for(len=0; len<32; len++){
 357         if(get_bits1(&s->gb)) break;
 358     }
 359
 360     if(len!=ff_mpeg4_get_video_packet_prefix_length(s)){
 361         av_log(s->avctx, AV_LOG_ERROR, "marker does not match f_code\n");
 362         return -1;
 363     }
 364
 365     if(s->shape != RECT_SHAPE){
 366         header_extension= get_bits1(&s->gb);
 367         //FIXME more stuff here
 368     }
 369
 370     mb_num= get_bits(&s->gb, mb_num_bits);
 371     if(mb_num>=s->mb_num){
 372         av_log(s->avctx, AV_LOG_ERROR, "illegal mb_num in video packet (%d %d) \n", mb_num, s->mb_num);
 373         return -1;
 374     }
 375     if(s->pict_type == FF_B_TYPE){
 376         while(s->next_picture.mbskip_table[ s->mb_index2xy[ mb_num ] ]) mb_num++;
 377         if(mb_num >= s->mb_num) return -1; // slice contains just skipped MBs which where already decoded
 378     }
 379
 380     s->mb_x= mb_num % s->mb_width;
 381     s->mb_y= mb_num / s->mb_width;
 382
 383     if(s->shape != BIN_ONLY_SHAPE){
 384         int qscale= get_bits(&s->gb, s->quant_precision);
 385         if(qscale)
 386             s->chroma_qscale=s->qscale= qscale;
 387     }
 388
 389     if(s->shape == RECT_SHAPE){
 390         header_extension= get_bits1(&s->gb);
 391     }
 392     if(header_extension){
 393         int time_increment;
 394         int time_incr=0;
 395
 396         while (get_bits1(&s->gb) != 0)
 397             time_incr++;
 398
 399         check_marker(&s->gb, "before time_increment in video packed header");
 400         time_increment= get_bits(&s->gb, s->time_increment_bits);
 401         check_marker(&s->gb, "before vop_coding_type in video packed header");
 402
 403         skip_bits(&s->gb, 2); /* vop coding type */
 404         //FIXME not rect stuff here
 405
 406         if(s->shape != BIN_ONLY_SHAPE){
 407             skip_bits(&s->gb, 3); /* intra dc vlc threshold */
 408 //FIXME don't just ignore everything
 409             if(s->pict_type == FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE){
 410                 mpeg4_decode_sprite_trajectory(s, &s->gb);
 411                 av_log(s->avctx, AV_LOG_ERROR, "untested\n");
 412             }
 413
 414             //FIXME reduced res stuff here
 415
 416             if (s->pict_type != FF_I_TYPE) {
 417                 int f_code = get_bits(&s->gb, 3);       /* fcode_for */
 418                 if(f_code==0){
 419                     av_log(s->avctx, AV_LOG_ERROR, "Error, video packet header damaged (f_code=0)\n");
 420                 }
 421             }
 422             if (s->pict_type == FF_B_TYPE) {
 423                 int b_code = get_bits(&s->gb, 3);
 424                 if(b_code==0){
 425                     av_log(s->avctx, AV_LOG_ERROR, "Error, video packet header damaged (b_code=0)\n");
 426                 }
 427             }
 428         }
 429     }
 430     //FIXME new-pred stuff
 431
 432     return 0;
 433 }
 434
 435 /**
 436  * gets the average motion vector for a GMC MB.
 437  * @param n either 0 for the x component or 1 for y
 438  * @return the average MV for a GMC MB
 439  */
 440 static inline int get_amv(MpegEncContext *s, int n){
 441     int x, y, mb_v, sum, dx, dy, shift;
 442     int len = 1 << (s->f_code + 4);
 443     const int a= s->sprite_warping_accuracy;
 444
 445     if(s->workaround_bugs & FF_BUG_AMV)
 446         len >>= s->quarter_sample;
 447
 448     if(s->real_sprite_warping_points==1){
 449         if(s->divx_version==500 && s->divx_build==413)
 450             sum= s->sprite_offset[0][n] / (1<<(a - s->quarter_sample));
 451         else
 452             sum= RSHIFT(s->sprite_offset[0][n]<<s->quarter_sample, a);
 453     }else{
 454         dx= s->sprite_delta[n][0];
 455         dy= s->sprite_delta[n][1];
 456         shift= s->sprite_shift[0];
 457         if(n) dy -= 1<<(shift + a + 1);
 458         else  dx -= 1<<(shift + a + 1);
 459         mb_v= s->sprite_offset[0][n] + dx*s->mb_x*16 + dy*s->mb_y*16;
 460
 461         sum=0;
 462         for(y=0; y<16; y++){
 463             int v;
 464
 465             v= mb_v + dy*y;
 466             //XXX FIXME optimize
 467             for(x=0; x<16; x++){
 468                 sum+= v>>shift;
 469                 v+= dx;
 470             }
 471         }
 472         sum= RSHIFT(sum, a+8-s->quarter_sample);
 473     }
 474
 475     if      (sum < -len) sum= -len;
 476     else if (sum >= len) sum= len-1;
 477
 478     return sum;
 479 }
 480
 481 /**
 482  * decodes the dc value.
 483  * @param n block index (0-3 are luma, 4-5 are chroma)
 484  * @param dir_ptr the prediction direction will be stored here
 485  * @return the quantized dc
 486  */
 487 static inline int mpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr)
 488 {
 489     int level, code;
 490
 491     if (n < 4)
 492         code = get_vlc2(&s->gb, dc_lum.table, DC_VLC_BITS, 1);
 493     else
 494         code = get_vlc2(&s->gb, dc_chrom.table, DC_VLC_BITS, 1);
 495     if (code < 0 || code > 9 /* && s->nbit<9 */){
 496         av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
 497         return -1;
 498     }
 499     if (code == 0) {
 500         level = 0;
 501     } else {
 502         if(IS_3IV1){
 503             if(code==1)
 504                 level= 2*get_bits1(&s->gb)-1;
 505             else{
 506                 if(get_bits1(&s->gb))
 507                     level = get_bits(&s->gb, code-1) + (1<<(code-1));
 508                 else
 509                     level = -get_bits(&s->gb, code-1) - (1<<(code-1));
 510             }
 511         }else{
 512             level = get_xbits(&s->gb, code);
 513         }
 514
 515         if (code > 8){
 516             if(get_bits1(&s->gb)==0){ /* marker */
 517                 if(s->error_recognition>=2){
 518                     av_log(s->avctx, AV_LOG_ERROR, "dc marker bit missing\n");
 519                     return -1;
 520                 }
 521             }
 522         }
 523     }
 524
 525     return ff_mpeg4_pred_dc(s, n, level, dir_ptr, 0);
 526 }
 527
 528 /**
 529  * decodes first partition.
 530  * @return number of MBs decoded or <0 if an error occurred
 531  */
 532 static int mpeg4_decode_partition_a(MpegEncContext *s){
 533     int mb_num;
 534     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 535
 536     /* decode first partition */
 537     mb_num=0;
 538     s->first_slice_line=1;
 539     for(; s->mb_y<s->mb_height; s->mb_y++){
 540         ff_init_block_index(s);
 541         for(; s->mb_x<s->mb_width; s->mb_x++){
 542             const int xy= s->mb_x + s->mb_y*s->mb_stride;
 543             int cbpc;
 544             int dir=0;
 545
 546             mb_num++;
 547             ff_update_block_index(s);
 548             if(s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y+1)
 549                 s->first_slice_line=0;
 550
 551             if(s->pict_type==FF_I_TYPE){
 552                 int i;
 553
 554                 do{
 555                     if(show_bits_long(&s->gb, 19)==DC_MARKER){
 556                         return mb_num-1;
 557                     }
 558
 559                     cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 560                     if (cbpc < 0){
 561                         av_log(s->avctx, AV_LOG_ERROR, "cbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 562                         return -1;
 563                     }
 564                 }while(cbpc == 8);
 565
 566                 s->cbp_table[xy]= cbpc & 3;
 567                 s->current_picture.mb_type[xy]= MB_TYPE_INTRA;
 568                 s->mb_intra = 1;
 569
 570                 if(cbpc & 4) {
 571                     ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 572                 }
 573                 s->current_picture.qscale_table[xy]= s->qscale;
 574
 575                 s->mbintra_table[xy]= 1;
 576                 for(i=0; i<6; i++){
 577                     int dc_pred_dir;
 578                     int dc= mpeg4_decode_dc(s, i, &dc_pred_dir);
 579                     if(dc < 0){
 580                         av_log(s->avctx, AV_LOG_ERROR, "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 581                         return -1;
 582                     }
 583                     dir<<=1;
 584                     if(dc_pred_dir) dir|=1;
 585                 }
 586                 s->pred_dir_table[xy]= dir;
 587             }else{ /* P/S_TYPE */
 588                 int mx, my, pred_x, pred_y, bits;
 589                 int16_t * const mot_val= s->current_picture.motion_val[0][s->block_index[0]];
 590                 const int stride= s->b8_stride*2;
 591
 592 try_again:
 593                 bits= show_bits(&s->gb, 17);
 594                 if(bits==MOTION_MARKER){
 595                     return mb_num-1;
 596                 }
 597                 skip_bits1(&s->gb);
 598                 if(bits&0x10000){
 599                     /* skip mb */
 600                     if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE){
 601                         s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_GMC | MB_TYPE_L0;
 602                         mx= get_amv(s, 0);
 603                         my= get_amv(s, 1);
 604                     }else{
 605                         s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 606                         mx=my=0;
 607                     }
 608                     mot_val[0       ]= mot_val[2       ]=
 609                     mot_val[0+stride]= mot_val[2+stride]= mx;
 610                     mot_val[1       ]= mot_val[3       ]=
 611                     mot_val[1+stride]= mot_val[3+stride]= my;
 612
 613                     if(s->mbintra_table[xy])
 614                         ff_clean_intra_table_entries(s);
 615                     continue;
 616                 }
 617
 618                 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 619                 if (cbpc < 0){
 620                     av_log(s->avctx, AV_LOG_ERROR, "cbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 621                     return -1;
 622                 }
 623                 if(cbpc == 20)
 624                     goto try_again;
 625
 626                 s->cbp_table[xy]= cbpc&(8+3); //8 is dquant
 627
 628                 s->mb_intra = ((cbpc & 4) != 0);
 629
 630                 if(s->mb_intra){
 631                     s->current_picture.mb_type[xy]= MB_TYPE_INTRA;
 632                     s->mbintra_table[xy]= 1;
 633                     mot_val[0       ]= mot_val[2       ]=
 634                     mot_val[0+stride]= mot_val[2+stride]= 0;
 635                     mot_val[1       ]= mot_val[3       ]=
 636                     mot_val[1+stride]= mot_val[3+stride]= 0;
 637                 }else{
 638                     if(s->mbintra_table[xy])
 639                         ff_clean_intra_table_entries(s);
 640
 641                     if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE && (cbpc & 16) == 0)
 642                         s->mcsel= get_bits1(&s->gb);
 643                     else s->mcsel= 0;
 644
 645                     if ((cbpc & 16) == 0) {
 646                         /* 16x16 motion prediction */
 647
 648                         h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 649                         if(!s->mcsel){
 650                             mx = h263_decode_motion(s, pred_x, s->f_code);
 651                             if (mx >= 0xffff)
 652                                 return -1;
 653
 654                             my = h263_decode_motion(s, pred_y, s->f_code);
 655                             if (my >= 0xffff)
 656                                 return -1;
 657                             s->current_picture.mb_type[xy]= MB_TYPE_16x16 | MB_TYPE_L0;
 658                         } else {
 659                             mx = get_amv(s, 0);
 660                             my = get_amv(s, 1);
 661                             s->current_picture.mb_type[xy]= MB_TYPE_16x16 | MB_TYPE_GMC | MB_TYPE_L0;
 662                         }
 663
 664                         mot_val[0       ]= mot_val[2       ] =
 665                         mot_val[0+stride]= mot_val[2+stride]= mx;
 666                         mot_val[1       ]= mot_val[3       ]=
 667                         mot_val[1+stride]= mot_val[3+stride]= my;
 668                     } else {
 669                         int i;
 670                         s->current_picture.mb_type[xy]= MB_TYPE_8x8 | MB_TYPE_L0;
 671                         for(i=0;i<4;i++) {
 672                             int16_t *mot_val= h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 673                             mx = h263_decode_motion(s, pred_x, s->f_code);
 674                             if (mx >= 0xffff)
 675                                 return -1;
 676
 677                             my = h263_decode_motion(s, pred_y, s->f_code);
 678                             if (my >= 0xffff)
 679                                 return -1;
 680                             mot_val[0] = mx;
 681                             mot_val[1] = my;
 682                         }
 683                     }
 684                 }
 685             }
 686         }
 687         s->mb_x= 0;
 688     }
 689
 690     return mb_num;
 691 }
 692
 693 /**
 694  * decode second partition.
 695  * @return <0 if an error occurred
 696  */
 697 static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count){
 698     int mb_num=0;
 699     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 700
 701     s->mb_x= s->resync_mb_x;
 702     s->first_slice_line=1;
 703     for(s->mb_y= s->resync_mb_y; mb_num < mb_count; s->mb_y++){
 704         ff_init_block_index(s);
 705         for(; mb_num < mb_count && s->mb_x<s->mb_width; s->mb_x++){
 706             const int xy= s->mb_x + s->mb_y*s->mb_stride;
 707
 708             mb_num++;
 709             ff_update_block_index(s);
 710             if(s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y+1)
 711                 s->first_slice_line=0;
 712
 713             if(s->pict_type==FF_I_TYPE){
 714                 int ac_pred= get_bits1(&s->gb);
 715                 int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 716                 if(cbpy<0){
 717                     av_log(s->avctx, AV_LOG_ERROR, "cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 718                     return -1;
 719                 }
 720
 721                 s->cbp_table[xy]|= cbpy<<2;
 722                 s->current_picture.mb_type[xy] |= ac_pred*MB_TYPE_ACPRED;
 723             }else{ /* P || S_TYPE */
 724                 if(IS_INTRA(s->current_picture.mb_type[xy])){
 725                     int dir=0,i;
 726                     int ac_pred = get_bits1(&s->gb);
 727                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 728
 729                     if(cbpy<0){
 730                         av_log(s->avctx, AV_LOG_ERROR, "I cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 731                         return -1;
 732                     }
 733
 734                     if(s->cbp_table[xy] & 8) {
 735                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 736                     }
 737                     s->current_picture.qscale_table[xy]= s->qscale;
 738
 739                     for(i=0; i<6; i++){
 740                         int dc_pred_dir;
 741                         int dc= mpeg4_decode_dc(s, i, &dc_pred_dir);
 742                         if(dc < 0){
 743                             av_log(s->avctx, AV_LOG_ERROR, "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 744                             return -1;
 745                         }
 746                         dir<<=1;
 747                         if(dc_pred_dir) dir|=1;
 748                     }
 749                     s->cbp_table[xy]&= 3; //remove dquant
 750                     s->cbp_table[xy]|= cbpy<<2;
 751                     s->current_picture.mb_type[xy] |= ac_pred*MB_TYPE_ACPRED;
 752                     s->pred_dir_table[xy]= dir;
 753                 }else if(IS_SKIP(s->current_picture.mb_type[xy])){
 754                     s->current_picture.qscale_table[xy]= s->qscale;
 755                     s->cbp_table[xy]= 0;
 756                 }else{
 757                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 758
 759                     if(cbpy<0){
 760                         av_log(s->avctx, AV_LOG_ERROR, "P cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 761                         return -1;
 762                     }
 763
 764                     if(s->cbp_table[xy] & 8) {
 765                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 766                     }
 767                     s->current_picture.qscale_table[xy]= s->qscale;
 768
 769                     s->cbp_table[xy]&= 3; //remove dquant
 770                     s->cbp_table[xy]|= (cbpy^0xf)<<2;
 771                 }
 772             }
 773         }
 774         if(mb_num >= mb_count) return 0;
 775         s->mb_x= 0;
 776     }
 777     return 0;
 778 }
 779
 780 /**
 781  * decodes the first & second partition
 782  * @return <0 if error (and sets error type in the error_status_table)
 783  */
 784 int ff_mpeg4_decode_partitions(MpegEncContext *s)
 785 {
 786     int mb_num;
 787     const int part_a_error= s->pict_type==FF_I_TYPE ? (DC_ERROR|MV_ERROR) : MV_ERROR;
 788     const int part_a_end  = s->pict_type==FF_I_TYPE ? (DC_END  |MV_END)   : MV_END;
 789
 790     mb_num= mpeg4_decode_partition_a(s);
 791     if(mb_num<0){
 792         ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, part_a_error);
 793         return -1;
 794     }
 795
 796     if(s->resync_mb_x + s->resync_mb_y*s->mb_width + mb_num > s->mb_num){
 797         av_log(s->avctx, AV_LOG_ERROR, "slice below monitor ...\n");
 798         ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, part_a_error);
 799         return -1;
 800     }
 801
 802     s->mb_num_left= mb_num;
 803
 804     if(s->pict_type==FF_I_TYPE){
 805         while(show_bits(&s->gb, 9) == 1)
 806             skip_bits(&s->gb, 9);
 807         if(get_bits_long(&s->gb, 19)!=DC_MARKER){
 808             av_log(s->avctx, AV_LOG_ERROR, "marker missing after first I partition at %d %d\n", s->mb_x, s->mb_y);
 809             return -1;
 810         }
 811     }else{
 812         while(show_bits(&s->gb, 10) == 1)
 813             skip_bits(&s->gb, 10);
 814         if(get_bits(&s->gb, 17)!=MOTION_MARKER){
 815             av_log(s->avctx, AV_LOG_ERROR, "marker missing after first P partition at %d %d\n", s->mb_x, s->mb_y);
 816             return -1;
 817         }
 818     }
 819     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, part_a_end);
 820
 821     if( mpeg4_decode_partition_b(s, mb_num) < 0){
 822         if(s->pict_type==FF_P_TYPE)
 823             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, DC_ERROR);
 824         return -1;
 825     }else{
 826         if(s->pict_type==FF_P_TYPE)
 827             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, DC_END);
 828     }
 829
 830     return 0;
 831 }
 832
 833 /**
 834  * decodes a block.
 835  * @return <0 if an error occurred
 836  */
 837 static inline int mpeg4_decode_block(MpegEncContext * s, DCTELEM * block,
 838                               int n, int coded, int intra, int rvlc)
 839 {
 840     int level, i, last, run;
 841     int dc_pred_dir;
 842     RLTable * rl;
 843     RL_VLC_ELEM * rl_vlc;
 844     const uint8_t * scan_table;
 845     int qmul, qadd;
 846
 847     //Note intra & rvlc should be optimized away if this is inlined
 848
 849     if(intra) {
 850       if(s->use_intra_dc_vlc){
 851         /* DC coef */
 852         if(s->partitioned_frame){
 853             level = s->dc_val[0][ s->block_index[n] ];
 854             if(n<4) level= FASTDIV((level + (s->y_dc_scale>>1)), s->y_dc_scale);
 855             else    level= FASTDIV((level + (s->c_dc_scale>>1)), s->c_dc_scale);
 856             dc_pred_dir= (s->pred_dir_table[s->mb_x + s->mb_y*s->mb_stride]<<n)&32;
 857         }else{
 858             level = mpeg4_decode_dc(s, n, &dc_pred_dir);
 859             if (level < 0)
 860                 return -1;
 861         }
 862         block[0] = level;
 863         i = 0;
 864       }else{
 865             i = -1;
 866             ff_mpeg4_pred_dc(s, n, 0, &dc_pred_dir, 0);
 867       }
 868       if (!coded)
 869           goto not_coded;
 870
 871       if(rvlc){
 872           rl = &rvlc_rl_intra;
 873           rl_vlc = rvlc_rl_intra.rl_vlc[0];
 874       }else{
 875           rl = &ff_mpeg4_rl_intra;
 876           rl_vlc = ff_mpeg4_rl_intra.rl_vlc[0];
 877       }
 878       if (s->ac_pred) {
 879           if (dc_pred_dir == 0)
 880               scan_table = s->intra_v_scantable.permutated; /* left */
 881           else
 882               scan_table = s->intra_h_scantable.permutated; /* top */
 883       } else {
 884             scan_table = s->intra_scantable.permutated;
 885       }
 886       qmul=1;
 887       qadd=0;
 888     } else {
 889         i = -1;
 890         if (!coded) {
 891             s->block_last_index[n] = i;
 892             return 0;
 893         }
 894         if(rvlc) rl = &rvlc_rl_inter;
 895         else     rl = &ff_h263_rl_inter;
 896
 897         scan_table = s->intra_scantable.permutated;
 898
 899         if(s->mpeg_quant){
 900             qmul=1;
 901             qadd=0;
 902             if(rvlc){
 903                 rl_vlc = rvlc_rl_inter.rl_vlc[0];
 904             }else{
 905                 rl_vlc = ff_h263_rl_inter.rl_vlc[0];
 906             }
 907         }else{
 908             qmul = s->qscale << 1;
 909             qadd = (s->qscale - 1) | 1;
 910             if(rvlc){
 911                 rl_vlc = rvlc_rl_inter.rl_vlc[s->qscale];
 912             }else{
 913                 rl_vlc = ff_h263_rl_inter.rl_vlc[s->qscale];
 914             }
 915         }
 916     }
 917   {
 918     OPEN_READER(re, &s->gb);
 919     for(;;) {
 920         UPDATE_CACHE(re, &s->gb);
 921         GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
 922         if (level==0) {
 923           /* escape */
 924           if(rvlc){
 925                 if(SHOW_UBITS(re, &s->gb, 1)==0){
 926                     av_log(s->avctx, AV_LOG_ERROR, "1. marker bit missing in rvlc esc\n");
 927                     return -1;
 928                 }; SKIP_CACHE(re, &s->gb, 1);
 929
 930                 last=  SHOW_UBITS(re, &s->gb, 1); SKIP_CACHE(re, &s->gb, 1);
 931                 run=   SHOW_UBITS(re, &s->gb, 6); LAST_SKIP_CACHE(re, &s->gb, 6);
 932                 SKIP_COUNTER(re, &s->gb, 1+1+6);
 933                 UPDATE_CACHE(re, &s->gb);
 934
 935                 if(SHOW_UBITS(re, &s->gb, 1)==0){
 936                     av_log(s->avctx, AV_LOG_ERROR, "2. marker bit missing in rvlc esc\n");
 937                     return -1;
 938                 }; SKIP_CACHE(re, &s->gb, 1);
 939
 940                 level= SHOW_UBITS(re, &s->gb, 11); SKIP_CACHE(re, &s->gb, 11);
 941
 942                 if(SHOW_UBITS(re, &s->gb, 5)!=0x10){
 943                     av_log(s->avctx, AV_LOG_ERROR, "reverse esc missing\n");
 944                     return -1;
 945                 }; SKIP_CACHE(re, &s->gb, 5);
 946
 947                 level=  level * qmul + qadd;
 948                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1); LAST_SKIP_CACHE(re, &s->gb, 1);
 949                 SKIP_COUNTER(re, &s->gb, 1+11+5+1);
 950
 951                 i+= run + 1;
 952                 if(last) i+=192;
 953           }else{
 954             int cache;
 955             cache= GET_CACHE(re, &s->gb);
 956
 957             if(IS_3IV1)
 958                 cache ^= 0xC0000000;
 959
 960             if (cache&0x80000000) {
 961                 if (cache&0x40000000) {
 962                     /* third escape */
 963                     SKIP_CACHE(re, &s->gb, 2);
 964                     last=  SHOW_UBITS(re, &s->gb, 1); SKIP_CACHE(re, &s->gb, 1);
 965                     run=   SHOW_UBITS(re, &s->gb, 6); LAST_SKIP_CACHE(re, &s->gb, 6);
 966                     SKIP_COUNTER(re, &s->gb, 2+1+6);
 967                     UPDATE_CACHE(re, &s->gb);
 968
 969                     if(IS_3IV1){
 970                         level= SHOW_SBITS(re, &s->gb, 12); LAST_SKIP_BITS(re, &s->gb, 12);
 971                     }else{
 972                         if(SHOW_UBITS(re, &s->gb, 1)==0){
 973                             av_log(s->avctx, AV_LOG_ERROR, "1. marker bit missing in 3. esc\n");
 974                             return -1;
 975                         }; SKIP_CACHE(re, &s->gb, 1);
 976
 977                         level= SHOW_SBITS(re, &s->gb, 12); SKIP_CACHE(re, &s->gb, 12);
 978
 979                         if(SHOW_UBITS(re, &s->gb, 1)==0){
 980                             av_log(s->avctx, AV_LOG_ERROR, "2. marker bit missing in 3. esc\n");
 981                             return -1;
 982                         }; LAST_SKIP_CACHE(re, &s->gb, 1);
 983
 984                         SKIP_COUNTER(re, &s->gb, 1+12+1);
 985                     }
 986
 987 #if 0
 988                     if(s->error_recognition >= FF_ER_COMPLIANT){
 989                         const int abs_level= FFABS(level);
 990                         if(abs_level<=MAX_LEVEL && run<=MAX_RUN){
 991                             const int run1= run - rl->max_run[last][abs_level] - 1;
 992                             if(abs_level <= rl->max_level[last][run]){
 993                                 av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, vlc encoding possible\n");
 994                                 return -1;
 995                             }
 996                             if(s->error_recognition > FF_ER_COMPLIANT){
 997                                 if(abs_level <= rl->max_level[last][run]*2){
 998                                     av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 1 encoding possible\n");
 999                                     return -1;
1000                                 }
1001                                 if(run1 >= 0 && abs_level <= rl->max_level[last][run1]){
1002                                     av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 2 encoding possible\n");
1003                                     return -1;
1004                                 }
1005                             }
1006                         }
1007                     }
1008 #endif
1009                     if (level>0) level= level * qmul + qadd;
1010                     else         level= level * qmul - qadd;
1011
1012                     if((unsigned)(level + 2048) > 4095){
1013                         if(s->error_recognition > FF_ER_COMPLIANT){
1014                             if(level > 2560 || level<-2560){
1015                                 av_log(s->avctx, AV_LOG_ERROR, "|level| overflow in 3. esc, qp=%d\n", s->qscale);
1016                                 return -1;
1017                             }
1018                         }
1019                         level= level<0 ? -2048 : 2047;
1020                     }
1021
1022                     i+= run + 1;
1023                     if(last) i+=192;
1024                 } else {
1025                     /* second escape */
1026                     SKIP_BITS(re, &s->gb, 2);
1027                     GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1028                     i+= run + rl->max_run[run>>7][level/qmul] +1; //FIXME opt indexing
1029                     level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1030                     LAST_SKIP_BITS(re, &s->gb, 1);
1031                 }
1032             } else {
1033                 /* first escape */
1034                 SKIP_BITS(re, &s->gb, 1);
1035                 GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1036                 i+= run;
1037                 level = level + rl->max_level[run>>7][(run-1)&63] * qmul;//FIXME opt indexing
1038                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1039                 LAST_SKIP_BITS(re, &s->gb, 1);
1040             }
1041           }
1042         } else {
1043             i+= run;
1044             level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1045             LAST_SKIP_BITS(re, &s->gb, 1);
1046         }
1047         if (i > 62){
1048             i-= 192;
1049             if(i&(~63)){
1050                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1051                 return -1;
1052             }
1053
1054             block[scan_table[i]] = level;
1055             break;
1056         }
1057
1058         block[scan_table[i]] = level;
1059     }
1060     CLOSE_READER(re, &s->gb);
1061   }
1062  not_coded:
1063     if (intra) {
1064         if(!s->use_intra_dc_vlc){
1065             block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0);
1066
1067             i -= i>>31; //if(i == -1) i=0;
1068         }
1069
1070         mpeg4_pred_ac(s, block, n, dc_pred_dir);
1071         if (s->ac_pred) {
1072             i = 63; /* XXX: not optimal */
1073         }
1074     }
1075     s->block_last_index[n] = i;
1076     return 0;
1077 }
1078
1079 /**
1080  * decode partition C of one MB.
1081  * @return <0 if an error occurred
1082  */
1083 static int mpeg4_decode_partitioned_mb(MpegEncContext *s, DCTELEM block[6][64])
1084 {
1085     int cbp, mb_type;
1086     const int xy= s->mb_x + s->mb_y*s->mb_stride;
1087
1088     mb_type= s->current_picture.mb_type[xy];
1089     cbp = s->cbp_table[xy];
1090
1091     s->use_intra_dc_vlc= s->qscale < s->intra_dc_threshold;
1092
1093     if(s->current_picture.qscale_table[xy] != s->qscale){
1094         ff_set_qscale(s, s->current_picture.qscale_table[xy] );
1095     }
1096
1097     if (s->pict_type == FF_P_TYPE || s->pict_type==FF_S_TYPE) {
1098         int i;
1099         for(i=0; i<4; i++){
1100             s->mv[0][i][0] = s->current_picture.motion_val[0][ s->block_index[i] ][0];
1101             s->mv[0][i][1] = s->current_picture.motion_val[0][ s->block_index[i] ][1];
1102         }
1103         s->mb_intra = IS_INTRA(mb_type);
1104
1105         if (IS_SKIP(mb_type)) {
1106             /* skip mb */
1107             for(i=0;i<6;i++)
1108                 s->block_last_index[i] = -1;
1109             s->mv_dir = MV_DIR_FORWARD;
1110             s->mv_type = MV_TYPE_16X16;
1111             if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE){
1112                 s->mcsel=1;
1113                 s->mb_skipped = 0;
1114             }else{
1115                 s->mcsel=0;
1116                 s->mb_skipped = 1;
1117             }
1118         }else if(s->mb_intra){
1119             s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1120         }else if(!s->mb_intra){
1121 //            s->mcsel= 0; //FIXME do we need to init that
1122
1123             s->mv_dir = MV_DIR_FORWARD;
1124             if (IS_8X8(mb_type)) {
1125                 s->mv_type = MV_TYPE_8X8;
1126             } else {
1127                 s->mv_type = MV_TYPE_16X16;
1128             }
1129         }
1130     } else { /* I-Frame */
1131         s->mb_intra = 1;
1132         s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1133     }
1134
1135     if (!IS_SKIP(mb_type)) {
1136         int i;
1137         s->dsp.clear_blocks(s->block[0]);
1138         /* decode each block */
1139         for (i = 0; i < 6; i++) {
1140             if(mpeg4_decode_block(s, block[i], i, cbp&32, s->mb_intra, s->rvlc) < 0){
1141                 av_log(s->avctx, AV_LOG_ERROR, "texture corrupted at %d %d %d\n", s->mb_x, s->mb_y, s->mb_intra);
1142                 return -1;
1143             }
1144             cbp+=cbp;
1145         }
1146     }
1147
1148     /* per-MB end of slice check */
1149
1150     if(--s->mb_num_left <= 0){
1151         if(mpeg4_is_resync(s))
1152             return SLICE_END;
1153         else
1154             return SLICE_NOEND;
1155     }else{
1156         if(mpeg4_is_resync(s)){
1157             const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1158             if(s->cbp_table[xy+delta])
1159                 return SLICE_END;
1160         }
1161         return SLICE_OK;
1162     }
1163 }
1164
1165 static int mpeg4_decode_mb(MpegEncContext *s,
1166                       DCTELEM block[6][64])
1167 {
1168     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
1169     int16_t *mot_val;
1170     static int8_t quant_tab[4] = { -1, -2, 1, 2 };
1171     const int xy= s->mb_x + s->mb_y * s->mb_stride;
1172
1173     assert(s->h263_pred);
1174
1175     if (s->pict_type == FF_P_TYPE || s->pict_type==FF_S_TYPE) {
1176         do{
1177             if (get_bits1(&s->gb)) {
1178                 /* skip mb */
1179                 s->mb_intra = 0;
1180                 for(i=0;i<6;i++)
1181                     s->block_last_index[i] = -1;
1182                 s->mv_dir = MV_DIR_FORWARD;
1183                 s->mv_type = MV_TYPE_16X16;
1184                 if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE){
1185                     s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_GMC | MB_TYPE_16x16 | MB_TYPE_L0;
1186                     s->mcsel=1;
1187                     s->mv[0][0][0]= get_amv(s, 0);
1188                     s->mv[0][0][1]= get_amv(s, 1);
1189
1190                     s->mb_skipped = 0;
1191                 }else{
1192                     s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
1193                     s->mcsel=0;
1194                     s->mv[0][0][0] = 0;
1195                     s->mv[0][0][1] = 0;
1196                     s->mb_skipped = 1;
1197                 }
1198                 goto end;
1199             }
1200             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
1201             if (cbpc < 0){
1202                 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1203                 return -1;
1204             }
1205         }while(cbpc == 20);
1206
1207         s->dsp.clear_blocks(s->block[0]);
1208         dquant = cbpc & 8;
1209         s->mb_intra = ((cbpc & 4) != 0);
1210         if (s->mb_intra) goto intra;
1211
1212         if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE && (cbpc & 16) == 0)
1213             s->mcsel= get_bits1(&s->gb);
1214         else s->mcsel= 0;
1215         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1) ^ 0x0F;
1216
1217         cbp = (cbpc & 3) | (cbpy << 2);
1218         if (dquant) {
1219             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1220         }
1221         if((!s->progressive_sequence) && (cbp || (s->workaround_bugs&FF_BUG_XVID_ILACE)))
1222             s->interlaced_dct= get_bits1(&s->gb);
1223
1224         s->mv_dir = MV_DIR_FORWARD;
1225         if ((cbpc & 16) == 0) {
1226             if(s->mcsel){
1227                 s->current_picture.mb_type[xy]= MB_TYPE_GMC | MB_TYPE_16x16 | MB_TYPE_L0;
1228                 /* 16x16 global motion prediction */
1229                 s->mv_type = MV_TYPE_16X16;
1230                 mx= get_amv(s, 0);
1231                 my= get_amv(s, 1);
1232                 s->mv[0][0][0] = mx;
1233                 s->mv[0][0][1] = my;
1234             }else if((!s->progressive_sequence) && get_bits1(&s->gb)){
1235                 s->current_picture.mb_type[xy]= MB_TYPE_16x8 | MB_TYPE_L0 | MB_TYPE_INTERLACED;
1236                 /* 16x8 field motion prediction */
1237                 s->mv_type= MV_TYPE_FIELD;
1238
1239                 s->field_select[0][0]= get_bits1(&s->gb);
1240                 s->field_select[0][1]= get_bits1(&s->gb);
1241
1242                 h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1243
1244                 for(i=0; i<2; i++){
1245                     mx = h263_decode_motion(s, pred_x, s->f_code);
1246                     if (mx >= 0xffff)
1247                         return -1;
1248
1249                     my = h263_decode_motion(s, pred_y/2, s->f_code);
1250                     if (my >= 0xffff)
1251                         return -1;
1252
1253                     s->mv[0][i][0] = mx;
1254                     s->mv[0][i][1] = my;
1255                 }
1256             }else{
1257                 s->current_picture.mb_type[xy]= MB_TYPE_16x16 | MB_TYPE_L0;
1258                 /* 16x16 motion prediction */
1259                 s->mv_type = MV_TYPE_16X16;
1260                 h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1261                 mx = h263_decode_motion(s, pred_x, s->f_code);
1262
1263                 if (mx >= 0xffff)
1264                     return -1;
1265
1266                 my = h263_decode_motion(s, pred_y, s->f_code);
1267
1268                 if (my >= 0xffff)
1269                     return -1;
1270                 s->mv[0][0][0] = mx;
1271                 s->mv[0][0][1] = my;
1272             }
1273         } else {
1274             s->current_picture.mb_type[xy]= MB_TYPE_8x8 | MB_TYPE_L0;
1275             s->mv_type = MV_TYPE_8X8;
1276             for(i=0;i<4;i++) {
1277                 mot_val = h263_pred_motion(s, i, 0, &pred_x, &pred_y);
1278                 mx = h263_decode_motion(s, pred_x, s->f_code);
1279                 if (mx >= 0xffff)
1280                     return -1;
1281
1282                 my = h263_decode_motion(s, pred_y, s->f_code);
1283                 if (my >= 0xffff)
1284                     return -1;
1285                 s->mv[0][i][0] = mx;
1286                 s->mv[0][i][1] = my;
1287                 mot_val[0] = mx;
1288                 mot_val[1] = my;
1289             }
1290         }
1291     } else if(s->pict_type==FF_B_TYPE) {
1292         int modb1; // first bit of modb
1293         int modb2; // second bit of modb
1294         int mb_type;
1295
1296         s->mb_intra = 0; //B-frames never contain intra blocks
1297         s->mcsel=0;      //     ...               true gmc blocks
1298
1299         if(s->mb_x==0){
1300             for(i=0; i<2; i++){
1301                 s->last_mv[i][0][0]=
1302                 s->last_mv[i][0][1]=
1303                 s->last_mv[i][1][0]=
1304                 s->last_mv[i][1][1]= 0;
1305             }
1306         }
1307
1308         /* if we skipped it in the future P Frame than skip it now too */
1309         s->mb_skipped= s->next_picture.mbskip_table[s->mb_y * s->mb_stride + s->mb_x]; // Note, skiptab=0 if last was GMC
1310
1311         if(s->mb_skipped){
1312                 /* skip mb */
1313             for(i=0;i<6;i++)
1314                 s->block_last_index[i] = -1;
1315
1316             s->mv_dir = MV_DIR_FORWARD;
1317             s->mv_type = MV_TYPE_16X16;
1318             s->mv[0][0][0] = 0;
1319             s->mv[0][0][1] = 0;
1320             s->mv[1][0][0] = 0;
1321             s->mv[1][0][1] = 0;
1322             s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
1323             goto end;
1324         }
1325
1326         modb1= get_bits1(&s->gb);
1327         if(modb1){
1328             mb_type= MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1; //like MB_TYPE_B_DIRECT but no vectors coded
1329             cbp=0;
1330         }else{
1331             modb2= get_bits1(&s->gb);
1332             mb_type= get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
1333             if(mb_type<0){
1334                 av_log(s->avctx, AV_LOG_ERROR, "illegal MB_type\n");
1335                 return -1;
1336             }
1337             mb_type= mb_type_b_map[ mb_type ];
1338             if(modb2) cbp= 0;
1339             else{
1340                 s->dsp.clear_blocks(s->block[0]);
1341                 cbp= get_bits(&s->gb, 6);
1342             }
1343
1344             if ((!IS_DIRECT(mb_type)) && cbp) {
1345                 if(get_bits1(&s->gb)){
1346                     ff_set_qscale(s, s->qscale + get_bits1(&s->gb)*4 - 2);
1347                 }
1348             }
1349
1350             if(!s->progressive_sequence){
1351                 if(cbp)
1352                     s->interlaced_dct= get_bits1(&s->gb);
1353
1354                 if(!IS_DIRECT(mb_type) && get_bits1(&s->gb)){
1355                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
1356                     mb_type &= ~MB_TYPE_16x16;
1357
1358                     if(USES_LIST(mb_type, 0)){
1359                         s->field_select[0][0]= get_bits1(&s->gb);
1360                         s->field_select[0][1]= get_bits1(&s->gb);
1361                     }
1362                     if(USES_LIST(mb_type, 1)){
1363                         s->field_select[1][0]= get_bits1(&s->gb);
1364                         s->field_select[1][1]= get_bits1(&s->gb);
1365                     }
1366                 }
1367             }
1368
1369             s->mv_dir = 0;
1370             if((mb_type & (MB_TYPE_DIRECT2|MB_TYPE_INTERLACED)) == 0){
1371                 s->mv_type= MV_TYPE_16X16;
1372
1373                 if(USES_LIST(mb_type, 0)){
1374                     s->mv_dir = MV_DIR_FORWARD;
1375
1376                     mx = h263_decode_motion(s, s->last_mv[0][0][0], s->f_code);
1377                     my = h263_decode_motion(s, s->last_mv[0][0][1], s->f_code);
1378                     s->last_mv[0][1][0]= s->last_mv[0][0][0]= s->mv[0][0][0] = mx;
1379                     s->last_mv[0][1][1]= s->last_mv[0][0][1]= s->mv[0][0][1] = my;
1380                 }
1381
1382                 if(USES_LIST(mb_type, 1)){
1383                     s->mv_dir |= MV_DIR_BACKWARD;
1384
1385                     mx = h263_decode_motion(s, s->last_mv[1][0][0], s->b_code);
1386                     my = h263_decode_motion(s, s->last_mv[1][0][1], s->b_code);
1387                     s->last_mv[1][1][0]= s->last_mv[1][0][0]= s->mv[1][0][0] = mx;
1388                     s->last_mv[1][1][1]= s->last_mv[1][0][1]= s->mv[1][0][1] = my;
1389                 }
1390             }else if(!IS_DIRECT(mb_type)){
1391                 s->mv_type= MV_TYPE_FIELD;
1392
1393                 if(USES_LIST(mb_type, 0)){
1394                     s->mv_dir = MV_DIR_FORWARD;
1395
1396                     for(i=0; i<2; i++){
1397                         mx = h263_decode_motion(s, s->last_mv[0][i][0]  , s->f_code);
1398                         my = h263_decode_motion(s, s->last_mv[0][i][1]/2, s->f_code);
1399                         s->last_mv[0][i][0]=  s->mv[0][i][0] = mx;
1400                         s->last_mv[0][i][1]= (s->mv[0][i][1] = my)*2;
1401                     }
1402                 }
1403
1404                 if(USES_LIST(mb_type, 1)){
1405                     s->mv_dir |= MV_DIR_BACKWARD;
1406
1407                     for(i=0; i<2; i++){
1408                         mx = h263_decode_motion(s, s->last_mv[1][i][0]  , s->b_code);
1409                         my = h263_decode_motion(s, s->last_mv[1][i][1]/2, s->b_code);
1410                         s->last_mv[1][i][0]=  s->mv[1][i][0] = mx;
1411                         s->last_mv[1][i][1]= (s->mv[1][i][1] = my)*2;
1412                     }
1413                 }
1414             }
1415         }
1416
1417         if(IS_DIRECT(mb_type)){
1418             if(IS_SKIP(mb_type))
1419                 mx=my=0;
1420             else{
1421                 mx = h263_decode_motion(s, 0, 1);
1422                 my = h263_decode_motion(s, 0, 1);
1423             }
1424
1425             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
1426             mb_type |= ff_mpeg4_set_direct_mv(s, mx, my);
1427         }
1428         s->current_picture.mb_type[xy]= mb_type;
1429     } else { /* I-Frame */
1430         do{
1431             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
1432             if (cbpc < 0){
1433                 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1434                 return -1;
1435             }
1436         }while(cbpc == 8);
1437
1438         dquant = cbpc & 4;
1439         s->mb_intra = 1;
1440 intra:
1441         s->ac_pred = get_bits1(&s->gb);
1442         if(s->ac_pred)
1443             s->current_picture.mb_type[xy]= MB_TYPE_INTRA | MB_TYPE_ACPRED;
1444         else
1445             s->current_picture.mb_type[xy]= MB_TYPE_INTRA;
1446
1447         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
1448         if(cbpy<0){
1449             av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
1450             return -1;
1451         }
1452         cbp = (cbpc & 3) | (cbpy << 2);
1453
1454         s->use_intra_dc_vlc= s->qscale < s->intra_dc_threshold;
1455
1456         if (dquant) {
1457             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1458         }
1459
1460         if(!s->progressive_sequence)
1461             s->interlaced_dct= get_bits1(&s->gb);
1462
1463         s->dsp.clear_blocks(s->block[0]);
1464         /* decode each block */
1465         for (i = 0; i < 6; i++) {
1466             if (mpeg4_decode_block(s, block[i], i, cbp&32, 1, 0) < 0)
1467                 return -1;
1468             cbp+=cbp;
1469         }
1470         goto end;
1471     }
1472
1473     /* decode each block */
1474     for (i = 0; i < 6; i++) {
1475         if (mpeg4_decode_block(s, block[i], i, cbp&32, 0, 0) < 0)
1476             return -1;
1477         cbp+=cbp;
1478     }
1479 end:
1480
1481         /* per-MB end of slice check */
1482     if(s->codec_id==CODEC_ID_MPEG4){
1483         if(mpeg4_is_resync(s)){
1484             const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1485             if(s->pict_type==FF_B_TYPE && s->next_picture.mbskip_table[xy + delta])
1486                 return SLICE_OK;
1487             return SLICE_END;
1488         }
1489     }
1490
1491     return SLICE_OK;
1492 }
1493
1494
1495 static int mpeg4_decode_gop_header(MpegEncContext * s, GetBitContext *gb){
1496     int hours, minutes, seconds;
1497     unsigned time_code = show_bits(gb, 18);
1498
1499     if (time_code & 0x40) {     /* marker_bit */
1500         hours   = time_code >> 13;
1501         minutes = time_code >>  7 & 0x3f;
1502         seconds = time_code       & 0x3f;
1503         s->time_base = seconds + 60*(minutes + 60*hours);
1504         skip_bits(gb, 20);      /* time_code, closed_gov, broken_link */
1505     } else {
1506         av_log(s->avctx, AV_LOG_WARNING, "GOP header missing marker_bit\n");
1507     }
1508
1509     return 0;
1510 }
1511
1512 static int decode_vol_header(MpegEncContext *s, GetBitContext *gb){
1513     int width, height, vo_ver_id;
1514
1515     /* vol header */
1516     skip_bits(gb, 1); /* random access */
1517     s->vo_type= get_bits(gb, 8);
1518     if (get_bits1(gb) != 0) { /* is_ol_id */
1519         vo_ver_id = get_bits(gb, 4); /* vo_ver_id */
1520         skip_bits(gb, 3); /* vo_priority */
1521     } else {
1522         vo_ver_id = 1;
1523     }
1524     s->aspect_ratio_info= get_bits(gb, 4);
1525     if(s->aspect_ratio_info == FF_ASPECT_EXTENDED){
1526         s->avctx->sample_aspect_ratio.num= get_bits(gb, 8); // par_width
1527         s->avctx->sample_aspect_ratio.den= get_bits(gb, 8); // par_height
1528     }else{
1529         s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1530     }
1531
1532     if ((s->vol_control_parameters=get_bits1(gb))) { /* vol control parameter */
1533         int chroma_format= get_bits(gb, 2);
1534         if(chroma_format!=CHROMA_420){
1535             av_log(s->avctx, AV_LOG_ERROR, "illegal chroma format\n");
1536         }
1537         s->low_delay= get_bits1(gb);
1538         if(get_bits1(gb)){ /* vbv parameters */
1539             get_bits(gb, 15);   /* first_half_bitrate */
1540             skip_bits1(gb);     /* marker */
1541             get_bits(gb, 15);   /* latter_half_bitrate */
1542             skip_bits1(gb);     /* marker */
1543             get_bits(gb, 15);   /* first_half_vbv_buffer_size */
1544             skip_bits1(gb);     /* marker */
1545             get_bits(gb, 3);    /* latter_half_vbv_buffer_size */
1546             get_bits(gb, 11);   /* first_half_vbv_occupancy */
1547             skip_bits1(gb);     /* marker */
1548             get_bits(gb, 15);   /* latter_half_vbv_occupancy */
1549             skip_bits1(gb);     /* marker */
1550         }
1551     }else{
1552         // set low delay flag only once the smartest? low delay detection won't be overriden
1553         if(s->picture_number==0)
1554             s->low_delay=0;
1555     }
1556
1557     s->shape = get_bits(gb, 2); /* vol shape */
1558     if(s->shape != RECT_SHAPE) av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
1559     if(s->shape == GRAY_SHAPE && vo_ver_id != 1){
1560         av_log(s->avctx, AV_LOG_ERROR, "Gray shape not supported\n");
1561         skip_bits(gb, 4);  //video_object_layer_shape_extension
1562     }
1563
1564     check_marker(gb, "before time_increment_resolution");
1565
1566     s->avctx->time_base.den = get_bits(gb, 16);
1567     if(!s->avctx->time_base.den){
1568         av_log(s->avctx, AV_LOG_ERROR, "time_base.den==0\n");
1569         s->avctx->time_base.num = 0;
1570         return -1;
1571     }
1572
1573     s->time_increment_bits = av_log2(s->avctx->time_base.den - 1) + 1;
1574     if (s->time_increment_bits < 1)
1575         s->time_increment_bits = 1;
1576
1577     check_marker(gb, "before fixed_vop_rate");
1578
1579     if (get_bits1(gb) != 0) {   /* fixed_vop_rate  */
1580         s->avctx->time_base.num = get_bits(gb, s->time_increment_bits);
1581     }else
1582         s->avctx->time_base.num = 1;
1583
1584     s->t_frame=0;
1585
1586     if (s->shape != BIN_ONLY_SHAPE) {
1587         if (s->shape == RECT_SHAPE) {
1588             skip_bits1(gb);   /* marker */
1589             width = get_bits(gb, 13);
1590             skip_bits1(gb);   /* marker */
1591             height = get_bits(gb, 13);
1592             skip_bits1(gb);   /* marker */
1593             if(width && height && !(s->width && s->codec_tag == AV_RL32("MP4S"))){ /* they should be non zero but who knows ... */
1594                 s->width = width;
1595                 s->height = height;
1596             }
1597         }
1598
1599         s->progressive_sequence=
1600         s->progressive_frame= get_bits1(gb)^1;
1601         s->interlaced_dct=0;
1602         if(!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
1603             av_log(s->avctx, AV_LOG_INFO, "MPEG4 OBMC not supported (very likely buggy encoder)\n");   /* OBMC Disable */
1604         if (vo_ver_id == 1) {
1605             s->vol_sprite_usage = get_bits1(gb); /* vol_sprite_usage */
1606         } else {
1607             s->vol_sprite_usage = get_bits(gb, 2); /* vol_sprite_usage */
1608         }
1609         if(s->vol_sprite_usage==STATIC_SPRITE) av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
1610         if(s->vol_sprite_usage==STATIC_SPRITE || s->vol_sprite_usage==GMC_SPRITE){
1611             if(s->vol_sprite_usage==STATIC_SPRITE){
1612                 s->sprite_width = get_bits(gb, 13);
1613                 skip_bits1(gb); /* marker */
1614                 s->sprite_height= get_bits(gb, 13);
1615                 skip_bits1(gb); /* marker */
1616                 s->sprite_left  = get_bits(gb, 13);
1617                 skip_bits1(gb); /* marker */
1618                 s->sprite_top   = get_bits(gb, 13);
1619                 skip_bits1(gb); /* marker */
1620             }
1621             s->num_sprite_warping_points= get_bits(gb, 6);
1622             if(s->num_sprite_warping_points > 3){
1623                 av_log(s->avctx, AV_LOG_ERROR, "%d sprite_warping_points\n", s->num_sprite_warping_points);
1624                 s->num_sprite_warping_points= 0;
1625                 return -1;
1626             }
1627             s->sprite_warping_accuracy = get_bits(gb, 2);
1628             s->sprite_brightness_change= get_bits1(gb);
1629             if(s->vol_sprite_usage==STATIC_SPRITE)
1630                 s->low_latency_sprite= get_bits1(gb);
1631         }
1632         // FIXME sadct disable bit if verid!=1 && shape not rect
1633
1634         if (get_bits1(gb) == 1) {   /* not_8_bit */
1635             s->quant_precision = get_bits(gb, 4); /* quant_precision */
1636             if(get_bits(gb, 4)!=8) av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n"); /* bits_per_pixel */
1637             if(s->quant_precision!=5) av_log(s->avctx, AV_LOG_ERROR, "quant precision %d\n", s->quant_precision);
1638         } else {
1639             s->quant_precision = 5;
1640         }
1641
1642         // FIXME a bunch of grayscale shape things
1643
1644         if((s->mpeg_quant=get_bits1(gb))){ /* vol_quant_type */
1645             int i, v;
1646
1647             /* load default matrixes */
1648             for(i=0; i<64; i++){
1649                 int j= s->dsp.idct_permutation[i];
1650                 v= ff_mpeg4_default_intra_matrix[i];
1651                 s->intra_matrix[j]= v;
1652                 s->chroma_intra_matrix[j]= v;
1653
1654                 v= ff_mpeg4_default_non_intra_matrix[i];
1655                 s->inter_matrix[j]= v;
1656                 s->chroma_inter_matrix[j]= v;
1657             }
1658
1659             /* load custom intra matrix */
1660             if(get_bits1(gb)){
1661                 int last=0;
1662                 for(i=0; i<64; i++){
1663                     int j;
1664                     v= get_bits(gb, 8);
1665                     if(v==0) break;
1666
1667                     last= v;
1668                     j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1669                     s->intra_matrix[j]= v;
1670                     s->chroma_intra_matrix[j]= v;
1671                 }
1672
1673                 /* replicate last value */
1674                 for(; i<64; i++){
1675                     int j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1676                     s->intra_matrix[j]= last;
1677                     s->chroma_intra_matrix[j]= last;
1678                 }
1679             }
1680
1681             /* load custom non intra matrix */
1682             if(get_bits1(gb)){
1683                 int last=0;
1684                 for(i=0; i<64; i++){
1685                     int j;
1686                     v= get_bits(gb, 8);
1687                     if(v==0) break;
1688
1689                     last= v;
1690                     j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1691                     s->inter_matrix[j]= v;
1692                     s->chroma_inter_matrix[j]= v;
1693                 }
1694
1695                 /* replicate last value */
1696                 for(; i<64; i++){
1697                     int j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1698                     s->inter_matrix[j]= last;
1699                     s->chroma_inter_matrix[j]= last;
1700                 }
1701             }
1702
1703             // FIXME a bunch of grayscale shape things
1704         }
1705
1706         if(vo_ver_id != 1)
1707              s->quarter_sample= get_bits1(gb);
1708         else s->quarter_sample=0;
1709
1710         if(!get_bits1(gb)){
1711             int pos= get_bits_count(gb);
1712             int estimation_method= get_bits(gb, 2);
1713             if(estimation_method<2){
1714                 if(!get_bits1(gb)){
1715                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //opaque
1716                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //transparent
1717                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //intra_cae
1718                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //inter_cae
1719                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //no_update
1720                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //upampling
1721                 }
1722                 if(!get_bits1(gb)){
1723                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //intra_blocks
1724                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //inter_blocks
1725                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //inter4v_blocks
1726                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //not coded blocks
1727                 }
1728                 if(!check_marker(gb, "in complexity estimation part 1")){
1729                     skip_bits_long(gb, pos - get_bits_count(gb));
1730                     goto no_cplx_est;
1731                 }
1732                 if(!get_bits1(gb)){
1733                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //dct_coeffs
1734                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //dct_lines
1735                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //vlc_syms
1736                     s->cplx_estimation_trash_i += 4*get_bits1(gb); //vlc_bits
1737                 }
1738                 if(!get_bits1(gb)){
1739                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //apm
1740                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //npm
1741                     s->cplx_estimation_trash_b += 8*get_bits1(gb); //interpolate_mc_q
1742                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //forwback_mc_q
1743                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //halfpel2
1744                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //halfpel4
1745                 }
1746                 if(!check_marker(gb, "in complexity estimation part 2")){
1747                     skip_bits_long(gb, pos - get_bits_count(gb));
1748                     goto no_cplx_est;
1749                 }
1750                 if(estimation_method==1){
1751                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //sadct
1752                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //qpel
1753                 }
1754             }else
1755                 av_log(s->avctx, AV_LOG_ERROR, "Invalid Complexity estimation method %d\n", estimation_method);
1756         }else{
1757 no_cplx_est:
1758             s->cplx_estimation_trash_i=
1759             s->cplx_estimation_trash_p=
1760             s->cplx_estimation_trash_b= 0;
1761         }
1762
1763         s->resync_marker= !get_bits1(gb); /* resync_marker_disabled */
1764
1765         s->data_partitioning= get_bits1(gb);
1766         if(s->data_partitioning){
1767             s->rvlc= get_bits1(gb);
1768         }
1769
1770         if(vo_ver_id != 1) {
1771             s->new_pred= get_bits1(gb);
1772             if(s->new_pred){
1773                 av_log(s->avctx, AV_LOG_ERROR, "new pred not supported\n");
1774                 skip_bits(gb, 2); /* requested upstream message type */
1775                 skip_bits1(gb); /* newpred segment type */
1776             }
1777             s->reduced_res_vop= get_bits1(gb);
1778             if(s->reduced_res_vop) av_log(s->avctx, AV_LOG_ERROR, "reduced resolution VOP not supported\n");
1779         }
1780         else{
1781             s->new_pred=0;
1782             s->reduced_res_vop= 0;
1783         }
1784
1785         s->scalability= get_bits1(gb);
1786
1787         if (s->scalability) {
1788             GetBitContext bak= *gb;
1789             int ref_layer_id;
1790             int ref_layer_sampling_dir;
1791             int h_sampling_factor_n;
1792             int h_sampling_factor_m;
1793             int v_sampling_factor_n;
1794             int v_sampling_factor_m;
1795
1796             s->hierachy_type= get_bits1(gb);
1797             ref_layer_id= get_bits(gb, 4);
1798             ref_layer_sampling_dir= get_bits1(gb);
1799             h_sampling_factor_n= get_bits(gb, 5);
1800             h_sampling_factor_m= get_bits(gb, 5);
1801             v_sampling_factor_n= get_bits(gb, 5);
1802             v_sampling_factor_m= get_bits(gb, 5);
1803             s->enhancement_type= get_bits1(gb);
1804
1805             if(   h_sampling_factor_n==0 || h_sampling_factor_m==0
1806                || v_sampling_factor_n==0 || v_sampling_factor_m==0){
1807                 /* illegal scalability header (VERY broken encoder),
1808                  * trying to workaround */
1809                 s->scalability=0;
1810                 *gb= bak;
1811             }else
1812                 av_log(s->avctx, AV_LOG_ERROR, "scalability not supported\n");
1813
1814             // bin shape stuff FIXME
1815         }
1816     }
1817     return 0;
1818 }
1819
1820 /**
1821  * decodes the user data stuff in the header.
1822  * Also initializes divx/xvid/lavc_version/build.
1823  */
1824 static int decode_user_data(MpegEncContext *s, GetBitContext *gb){
1825     char buf[256];
1826     int i;
1827     int e;
1828     int ver = 0, build = 0, ver2 = 0, ver3 = 0;
1829     char last;
1830
1831     for(i=0; i<255 && get_bits_count(gb) < gb->size_in_bits; i++){
1832         if(show_bits(gb, 23) == 0) break;
1833         buf[i]= get_bits(gb, 8);
1834     }
1835     buf[i]=0;
1836
1837     /* divx detection */
1838     e=sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
1839     if(e<2)
1840         e=sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
1841     if(e>=2){
1842         s->divx_version= ver;
1843         s->divx_build= build;
1844         s->divx_packed= e==3 && last=='p';
1845         if(s->divx_packed && !s->showed_packed_warning) {
1846             av_log(s->avctx, AV_LOG_WARNING, "Invalid and inefficient vfw-avi packed B frames detected\n");
1847             s->showed_packed_warning=1;
1848         }
1849     }
1850
1851     /* ffmpeg detection */
1852     e=sscanf(buf, "FFmpe%*[^b]b%d", &build)+3;
1853     if(e!=4)
1854         e=sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
1855     if(e!=4){
1856         e=sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3)+1;
1857         if (e>1)
1858             build= (ver<<16) + (ver2<<8) + ver3;
1859     }
1860     if(e!=4){
1861         if(strcmp(buf, "ffmpeg")==0){
1862             s->lavc_build= 4600;
1863         }
1864     }
1865     if(e==4){
1866         s->lavc_build= build;
1867     }
1868
1869     /* Xvid detection */
1870     e=sscanf(buf, "XviD%d", &build);
1871     if(e==1){
1872         s->xvid_build= build;
1873     }
1874
1875     return 0;
1876 }
1877
1878 static int decode_vop_header(MpegEncContext *s, GetBitContext *gb){
1879     int time_incr, time_increment;
1880
1881     s->pict_type = get_bits(gb, 2) + FF_I_TYPE;        /* pict type: I = 0 , P = 1 */
1882     if(s->pict_type==FF_B_TYPE && s->low_delay && s->vol_control_parameters==0 && !(s->flags & CODEC_FLAG_LOW_DELAY)){
1883         av_log(s->avctx, AV_LOG_ERROR, "low_delay flag incorrectly, clearing it\n");
1884         s->low_delay=0;
1885     }
1886
1887     s->partitioned_frame= s->data_partitioning && s->pict_type!=FF_B_TYPE;
1888     if(s->partitioned_frame)
1889         s->decode_mb= mpeg4_decode_partitioned_mb;
1890     else
1891         s->decode_mb= mpeg4_decode_mb;
1892
1893     time_incr=0;
1894     while (get_bits1(gb) != 0)
1895         time_incr++;
1896
1897     check_marker(gb, "before time_increment");
1898
1899     if(s->time_increment_bits==0 || !(show_bits(gb, s->time_increment_bits+1)&1)){
1900         av_log(s->avctx, AV_LOG_ERROR, "hmm, seems the headers are not complete, trying to guess time_increment_bits\n");
1901
1902         for(s->time_increment_bits=1 ;s->time_increment_bits<16; s->time_increment_bits++){
1903             if (    s->pict_type == FF_P_TYPE
1904                 || (s->pict_type == FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE)) {
1905                 if((show_bits(gb, s->time_increment_bits+6)&0x37) == 0x30) break;
1906             }else
1907                 if((show_bits(gb, s->time_increment_bits+5)&0x1F) == 0x18) break;
1908         }
1909
1910         av_log(s->avctx, AV_LOG_ERROR, "my guess is %d bits ;)\n",s->time_increment_bits);
1911     }
1912
1913     if(IS_3IV1) time_increment= get_bits1(gb); //FIXME investigate further
1914     else time_increment= get_bits(gb, s->time_increment_bits);
1915
1916     if(s->pict_type!=FF_B_TYPE){
1917         s->last_time_base= s->time_base;
1918         s->time_base+= time_incr;
1919         s->time= s->time_base*s->avctx->time_base.den + time_increment;
1920         if(s->workaround_bugs&FF_BUG_UMP4){
1921             if(s->time < s->last_non_b_time){
1922                 /* header is not mpeg-4-compatible, broken encoder,
1923                  * trying to workaround */
1924                 s->time_base++;
1925                 s->time+= s->avctx->time_base.den;
1926             }
1927         }
1928         s->pp_time= s->time - s->last_non_b_time;
1929         s->last_non_b_time= s->time;
1930     }else{
1931         s->time= (s->last_time_base + time_incr)*s->avctx->time_base.den + time_increment;
1932         s->pb_time= s->pp_time - (s->last_non_b_time - s->time);
1933         if(s->pp_time <=s->pb_time || s->pp_time <= s->pp_time - s->pb_time || s->pp_time<=0){
1934             /* messed up order, maybe after seeking? skipping current b-frame */
1935             return FRAME_SKIPPED;
1936         }
1937         ff_mpeg4_init_direct_mv(s);
1938
1939         if(s->t_frame==0) s->t_frame= s->pb_time;
1940         if(s->t_frame==0) s->t_frame=1; // 1/0 protection
1941         s->pp_field_time= (  ROUNDED_DIV(s->last_non_b_time, s->t_frame)
1942                            - ROUNDED_DIV(s->last_non_b_time - s->pp_time, s->t_frame))*2;
1943         s->pb_field_time= (  ROUNDED_DIV(s->time, s->t_frame)
1944                            - ROUNDED_DIV(s->last_non_b_time - s->pp_time, s->t_frame))*2;
1945         if(!s->progressive_sequence){
1946             if(s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1)
1947                 return FRAME_SKIPPED;
1948         }
1949     }
1950
1951     if(s->avctx->time_base.num)
1952         s->current_picture_ptr->pts= (s->time + s->avctx->time_base.num/2) / s->avctx->time_base.num;
1953     else
1954         s->current_picture_ptr->pts= AV_NOPTS_VALUE;
1955     if(s->avctx->debug&FF_DEBUG_PTS)
1956         av_log(s->avctx, AV_LOG_DEBUG, "MPEG4 PTS: %"PRId64"\n", s->current_picture_ptr->pts);
1957
1958     check_marker(gb, "before vop_coded");
1959
1960     /* vop coded */
1961     if (get_bits1(gb) != 1){
1962         if(s->avctx->debug&FF_DEBUG_PICT_INFO)
1963             av_log(s->avctx, AV_LOG_ERROR, "vop not coded\n");
1964         return FRAME_SKIPPED;
1965     }
1966     if (s->shape != BIN_ONLY_SHAPE && ( s->pict_type == FF_P_TYPE
1967                           || (s->pict_type == FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE))) {
1968         /* rounding type for motion estimation */
1969         s->no_rounding = get_bits1(gb);
1970     } else {
1971         s->no_rounding = 0;
1972     }
1973 //FIXME reduced res stuff
1974
1975      if (s->shape != RECT_SHAPE) {
1976          if (s->vol_sprite_usage != 1 || s->pict_type != FF_I_TYPE) {
1977              int width, height, hor_spat_ref, ver_spat_ref;
1978
1979              width = get_bits(gb, 13);
1980              skip_bits1(gb);   /* marker */
1981              height = get_bits(gb, 13);
1982              skip_bits1(gb);   /* marker */
1983              hor_spat_ref = get_bits(gb, 13); /* hor_spat_ref */
1984              skip_bits1(gb);   /* marker */
1985              ver_spat_ref = get_bits(gb, 13); /* ver_spat_ref */
1986          }
1987          skip_bits1(gb); /* change_CR_disable */
1988
1989          if (get_bits1(gb) != 0) {
1990              skip_bits(gb, 8); /* constant_alpha_value */
1991          }
1992      }
1993 //FIXME complexity estimation stuff
1994
1995      if (s->shape != BIN_ONLY_SHAPE) {
1996          skip_bits_long(gb, s->cplx_estimation_trash_i);
1997          if(s->pict_type != FF_I_TYPE)
1998             skip_bits_long(gb, s->cplx_estimation_trash_p);
1999          if(s->pict_type == FF_B_TYPE)
2000             skip_bits_long(gb, s->cplx_estimation_trash_b);
2001
2002          s->intra_dc_threshold= mpeg4_dc_threshold[ get_bits(gb, 3) ];
2003          if(!s->progressive_sequence){
2004              s->top_field_first= get_bits1(gb);
2005              s->alternate_scan= get_bits1(gb);
2006          }else
2007              s->alternate_scan= 0;
2008      }
2009
2010      if(s->alternate_scan){
2011          ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_alternate_vertical_scan);
2012          ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_alternate_vertical_scan);
2013          ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
2014          ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2015      } else{
2016          ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_zigzag_direct);
2017          ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_zigzag_direct);
2018          ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
2019          ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2020      }
2021
2022      if(s->pict_type == FF_S_TYPE && (s->vol_sprite_usage==STATIC_SPRITE || s->vol_sprite_usage==GMC_SPRITE)){
2023          mpeg4_decode_sprite_trajectory(s, gb);
2024          if(s->sprite_brightness_change) av_log(s->avctx, AV_LOG_ERROR, "sprite_brightness_change not supported\n");
2025          if(s->vol_sprite_usage==STATIC_SPRITE) av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
2026      }
2027
2028      if (s->shape != BIN_ONLY_SHAPE) {
2029          s->chroma_qscale= s->qscale = get_bits(gb, s->quant_precision);
2030          if(s->qscale==0){
2031              av_log(s->avctx, AV_LOG_ERROR, "Error, header damaged or not MPEG4 header (qscale=0)\n");
2032              return -1; // makes no sense to continue, as there is nothing left from the image then
2033          }
2034
2035          if (s->pict_type != FF_I_TYPE) {
2036              s->f_code = get_bits(gb, 3);       /* fcode_for */
2037              if(s->f_code==0){
2038                  av_log(s->avctx, AV_LOG_ERROR, "Error, header damaged or not MPEG4 header (f_code=0)\n");
2039                  return -1; // makes no sense to continue, as the MV decoding will break very quickly
2040              }
2041          }else
2042              s->f_code=1;
2043
2044          if (s->pict_type == FF_B_TYPE) {
2045              s->b_code = get_bits(gb, 3);
2046          }else
2047              s->b_code=1;
2048
2049          if(s->avctx->debug&FF_DEBUG_PICT_INFO){
2050              av_log(s->avctx, AV_LOG_DEBUG, "qp:%d fc:%d,%d %s size:%d pro:%d alt:%d top:%d %spel part:%d resync:%d w:%d a:%d rnd:%d vot:%d%s dc:%d ce:%d/%d/%d\n",
2051                  s->qscale, s->f_code, s->b_code,
2052                  s->pict_type == FF_I_TYPE ? "I" : (s->pict_type == FF_P_TYPE ? "P" : (s->pict_type == FF_B_TYPE ? "B" : "S")),
2053                  gb->size_in_bits,s->progressive_sequence, s->alternate_scan, s->top_field_first,
2054                  s->quarter_sample ? "q" : "h", s->data_partitioning, s->resync_marker, s->num_sprite_warping_points,
2055                  s->sprite_warping_accuracy, 1-s->no_rounding, s->vo_type, s->vol_control_parameters ? " VOLC" : " ", s->intra_dc_threshold, s->cplx_estimation_trash_i, s->cplx_estimation_trash_p, s->cplx_estimation_trash_b);
2056          }
2057
2058          if(!s->scalability){
2059              if (s->shape!=RECT_SHAPE && s->pict_type!=FF_I_TYPE) {
2060                  skip_bits1(gb); // vop shape coding type
2061              }
2062          }else{
2063              if(s->enhancement_type){
2064                  int load_backward_shape= get_bits1(gb);
2065                  if(load_backward_shape){
2066                      av_log(s->avctx, AV_LOG_ERROR, "load backward shape isn't supported\n");
2067                  }
2068              }
2069              skip_bits(gb, 2); //ref_select_code
2070          }
2071      }
2072      /* detect buggy encoders which don't set the low_delay flag (divx4/xvid/opendivx)*/
2073      // note we cannot detect divx5 without b-frames easily (although it's buggy too)
2074      if(s->vo_type==0 && s->vol_control_parameters==0 && s->divx_version==-1 && s->picture_number==0){
2075          av_log(s->avctx, AV_LOG_WARNING, "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
2076          s->low_delay=1;
2077      }
2078
2079      s->picture_number++; // better than pic number==0 always ;)
2080
2081      s->y_dc_scale_table= ff_mpeg4_y_dc_scale_table; //FIXME add short header support
2082      s->c_dc_scale_table= ff_mpeg4_c_dc_scale_table;
2083
2084      if(s->workaround_bugs&FF_BUG_EDGE){
2085          s->h_edge_pos= s->width;
2086          s->v_edge_pos= s->height;
2087      }
2088      return 0;
2089 }
2090
2091 /**
2092  * decode mpeg4 headers
2093  * @return <0 if no VOP found (or a damaged one)
2094  *         FRAME_SKIPPED if a not coded VOP is found
2095  *         0 if a VOP is found
2096  */
2097 int ff_mpeg4_decode_picture_header(MpegEncContext * s, GetBitContext *gb)
2098 {
2099     int startcode, v;
2100
2101     /* search next start code */
2102     align_get_bits(gb);
2103
2104     if(s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630){
2105         skip_bits(gb, 24);
2106         if(get_bits(gb, 8) == 0xF0)
2107             goto end;
2108     }
2109
2110     startcode = 0xff;
2111     for(;;) {
2112         if(get_bits_count(gb) >= gb->size_in_bits){
2113             if(gb->size_in_bits==8 && (s->divx_version>=0 || s->xvid_build>=0)){
2114                 av_log(s->avctx, AV_LOG_WARNING, "frame skip %d\n", gb->size_in_bits);
2115                 return FRAME_SKIPPED; //divx bug
2116             }else
2117                 return -1; //end of stream
2118         }
2119
2120         /* use the bits after the test */
2121         v = get_bits(gb, 8);
2122         startcode = ((startcode << 8) | v) & 0xffffffff;
2123
2124         if((startcode&0xFFFFFF00) != 0x100)
2125             continue; //no startcode
2126
2127         if(s->avctx->debug&FF_DEBUG_STARTCODE){
2128             av_log(s->avctx, AV_LOG_DEBUG, "startcode: %3X ", startcode);
2129             if     (startcode<=0x11F) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
2130             else if(startcode<=0x12F) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
2131             else if(startcode<=0x13F) av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2132             else if(startcode<=0x15F) av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
2133             else if(startcode<=0x1AF) av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2134             else if(startcode==0x1B0) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
2135             else if(startcode==0x1B1) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
2136             else if(startcode==0x1B2) av_log(s->avctx, AV_LOG_DEBUG, "User Data");
2137             else if(startcode==0x1B3) av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
2138             else if(startcode==0x1B4) av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
2139             else if(startcode==0x1B5) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
2140             else if(startcode==0x1B6) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
2141             else if(startcode==0x1B7) av_log(s->avctx, AV_LOG_DEBUG, "slice start");
2142             else if(startcode==0x1B8) av_log(s->avctx, AV_LOG_DEBUG, "extension start");
2143             else if(startcode==0x1B9) av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
2144             else if(startcode==0x1BA) av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
2145             else if(startcode==0x1BB) av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
2146             else if(startcode==0x1BC) av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
2147             else if(startcode==0x1BD) av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
2148             else if(startcode==0x1BE) av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
2149             else if(startcode==0x1BF) av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
2150             else if(startcode==0x1C0) av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
2151             else if(startcode==0x1C1) av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
2152             else if(startcode==0x1C2) av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
2153             else if(startcode==0x1C3) av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
2154             else if(startcode<=0x1C5) av_log(s->avctx, AV_LOG_DEBUG, "reserved");
2155             else if(startcode<=0x1FF) av_log(s->avctx, AV_LOG_DEBUG, "System start");
2156             av_log(s->avctx, AV_LOG_DEBUG, " at %d\n", get_bits_count(gb));
2157         }
2158
2159         if(startcode >= 0x120 && startcode <= 0x12F){
2160             if(decode_vol_header(s, gb) < 0)
2161                 return -1;
2162         }
2163         else if(startcode == USER_DATA_STARTCODE){
2164             decode_user_data(s, gb);
2165         }
2166         else if(startcode == GOP_STARTCODE){
2167             mpeg4_decode_gop_header(s, gb);
2168         }
2169         else if(startcode == VOP_STARTCODE){
2170             break;
2171         }
2172
2173         align_get_bits(gb);
2174         startcode = 0xff;
2175     }
2176 end:
2177     if(s->flags& CODEC_FLAG_LOW_DELAY)
2178         s->low_delay=1;
2179     s->avctx->has_b_frames= !s->low_delay;
2180     return decode_vop_header(s, gb);
2181 }
2182
2183 static av_cold int decode_init(AVCodecContext *avctx)
2184 {
2185     MpegEncContext *s = avctx->priv_data;
2186     int ret;
2187     static int done = 0;
2188
2189     s->divx_version=
2190     s->divx_build=
2191     s->xvid_build=
2192     s->lavc_build= -1;
2193
2194     if((ret=ff_h263_decode_init(avctx)) < 0)
2195         return ret;
2196
2197     if (!done) {
2198         done = 1;
2199
2200         init_rl(&ff_mpeg4_rl_intra, ff_mpeg4_static_rl_table_store[0]);
2201         init_rl(&rvlc_rl_inter, ff_mpeg4_static_rl_table_store[1]);
2202         init_rl(&rvlc_rl_intra, ff_mpeg4_static_rl_table_store[2]);
2203         INIT_VLC_RL(ff_mpeg4_rl_intra, 554);
2204         INIT_VLC_RL(rvlc_rl_inter, 1072);
2205         INIT_VLC_RL(rvlc_rl_intra, 1072);
2206         INIT_VLC_STATIC(&dc_lum, DC_VLC_BITS, 10 /* 13 */,
2207                  &ff_mpeg4_DCtab_lum[0][1], 2, 1,
2208                  &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
2209         INIT_VLC_STATIC(&dc_chrom, DC_VLC_BITS, 10 /* 13 */,
2210                  &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
2211                  &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
2212         INIT_VLC_STATIC(&sprite_trajectory, SPRITE_TRAJ_VLC_BITS, 15,
2213                  &sprite_trajectory_tab[0][1], 4, 2,
2214                  &sprite_trajectory_tab[0][0], 4, 2, 128);
2215         INIT_VLC_STATIC(&mb_type_b_vlc, MB_TYPE_B_VLC_BITS, 4,
2216                  &mb_type_b_tab[0][1], 2, 1,
2217                  &mb_type_b_tab[0][0], 2, 1, 16);
2218     }
2219
2220     s->h263_pred = 1;
2221     s->low_delay = 0; //default, might be overriden in the vol header during header parsing
2222     s->decode_mb= mpeg4_decode_mb;
2223     s->time_increment_bits = 4; /* default value for broken headers */
2224     avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
2225
2226     return 0;
2227 }
2228
2229 AVCodec ff_mpeg4_decoder = {
2230     "mpeg4",
2231     AVMEDIA_TYPE_VIDEO,
2232     CODEC_ID_MPEG4,
2233     sizeof(MpegEncContext),
2234     decode_init,
2235     NULL,
2236     ff_h263_decode_end,
2237     ff_h263_decode_frame,
2238     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
2239     .flush= ff_mpeg_flush,
2240     .max_lowres= 3,
2241     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
2242     .pix_fmts= ff_hwaccel_pixfmt_list_420,
2243 };
2244
2245
2246 #if CONFIG_MPEG4_VDPAU_DECODER
2247 AVCodec ff_mpeg4_vdpau_decoder = {
2248     "mpeg4_vdpau",
2249     AVMEDIA_TYPE_VIDEO,
2250     CODEC_ID_MPEG4,
2251     sizeof(MpegEncContext),
2252     decode_init,
2253     NULL,
2254     ff_h263_decode_end,
2255     ff_h263_decode_frame,
2256     CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY | CODEC_CAP_HWACCEL_VDPAU,
2257     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),
2258     .pix_fmts= (const enum PixelFormat[]){PIX_FMT_VDPAU_MPEG4, PIX_FMT_NONE},
2259 };
2260 #endif