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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 FFmpeg.
   7  *
   8  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #include "thread.h"
  27
  28 // The defines below define the number of bits that are read at once for
  29 // reading vlc values. Changing these may improve speed and data cache needs
  30 // be aware though that decreasing them may need the number of stages that is
  31 // passed to get_vlc* to be increased.
  32 #define SPRITE_TRAJ_VLC_BITS 6
  33 #define DC_VLC_BITS 9
  34 #define MB_TYPE_B_VLC_BITS 4
  35
  36
  37 static VLC dc_lum, dc_chrom;
  38 static VLC sprite_trajectory;
  39 static VLC mb_type_b_vlc;
  40
  41 static const int mb_type_b_map[4]= {
  42     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
  43     MB_TYPE_L0L1 | MB_TYPE_16x16,
  44     MB_TYPE_L1 | MB_TYPE_16x16,
  45     MB_TYPE_L0 | MB_TYPE_16x16,
  46 };
  47
  48 /**
  49  * predicts the ac.
  50  * @param n block index (0-3 are luma, 4-5 are chroma)
  51  * @param dir the ac prediction direction
  52  */
  53 void mpeg4_pred_ac(MpegEncContext * s, DCTELEM *block, int n,
  54                    int dir)
  55 {
  56     int i;
  57     int16_t *ac_val, *ac_val1;
  58     int8_t * const qscale_table= s->current_picture.qscale_table;
  59
  60     /* find prediction */
  61     ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
  62     ac_val1 = ac_val;
  63     if (s->ac_pred) {
  64         if (dir == 0) {
  65             const int xy= s->mb_x-1 + s->mb_y*s->mb_stride;
  66             /* left prediction */
  67             ac_val -= 16;
  68
  69             if(s->mb_x==0 || s->qscale == qscale_table[xy] || n==1 || n==3){
  70                 /* same qscale */
  71                 for(i=1;i<8;i++) {
  72                     block[s->dsp.idct_permutation[i<<3]] += ac_val[i];
  73                 }
  74             }else{
  75                 /* different qscale, we must rescale */
  76                 for(i=1;i<8;i++) {
  77                     block[s->dsp.idct_permutation[i<<3]] += ROUNDED_DIV(ac_val[i]*qscale_table[xy], s->qscale);
  78                 }
  79             }
  80         } else {
  81             const int xy= s->mb_x + s->mb_y*s->mb_stride - s->mb_stride;
  82             /* top prediction */
  83             ac_val -= 16 * s->block_wrap[n];
  84
  85             if(s->mb_y==0 || s->qscale == qscale_table[xy] || n==2 || n==3){
  86                 /* same qscale */
  87                 for(i=1;i<8;i++) {
  88                     block[s->dsp.idct_permutation[i]] += ac_val[i + 8];
  89                 }
  90             }else{
  91                 /* different qscale, we must rescale */
  92                 for(i=1;i<8;i++) {
  93                     block[s->dsp.idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8]*qscale_table[xy], s->qscale);
  94                 }
  95             }
  96         }
  97     }
  98     /* left copy */
  99     for(i=1;i<8;i++)
 100         ac_val1[i    ] = block[s->dsp.idct_permutation[i<<3]];
 101
 102     /* top copy */
 103     for(i=1;i<8;i++)
 104         ac_val1[8 + i] = block[s->dsp.idct_permutation[i   ]];
 105
 106 }
 107
 108 /**
 109  * check if the next stuff is a resync marker or the end.
 110  * @return 0 if not
 111  */
 112 static inline int mpeg4_is_resync(MpegEncContext *s){
 113     int bits_count= get_bits_count(&s->gb);
 114     int v= show_bits(&s->gb, 16);
 115
 116     if(s->workaround_bugs&FF_BUG_NO_PADDING){
 117         return 0;
 118     }
 119
 120     while(v<=0xFF){
 121         if(s->pict_type==FF_B_TYPE || (v>>(8-s->pict_type)!=1) || s->partitioned_frame)
 122             break;
 123         skip_bits(&s->gb, 8+s->pict_type);
 124         bits_count+= 8+s->pict_type;
 125         v= show_bits(&s->gb, 16);
 126     }
 127
 128     if(bits_count + 8 >= s->gb.size_in_bits){
 129         v>>=8;
 130         v|= 0x7F >> (7-(bits_count&7));
 131
 132         if(v==0x7F)
 133             return 1;
 134     }else{
 135         if(v == ff_mpeg4_resync_prefix[bits_count&7]){
 136             int len;
 137             GetBitContext gb= s->gb;
 138
 139             skip_bits(&s->gb, 1);
 140             align_get_bits(&s->gb);
 141
 142             for(len=0; len<32; len++){
 143                 if(get_bits1(&s->gb)) break;
 144             }
 145
 146             s->gb= gb;
 147
 148             if(len>=ff_mpeg4_get_video_packet_prefix_length(s))
 149                 return 1;
 150         }
 151     }
 152     return 0;
 153 }
 154
 155 static void mpeg4_decode_sprite_trajectory(MpegEncContext * s, GetBitContext *gb)
 156 {
 157     int i;
 158     int a= 2<<s->sprite_warping_accuracy;
 159     int rho= 3-s->sprite_warping_accuracy;
 160     int r=16/a;
 161     const int vop_ref[4][2]= {{0,0}, {s->width,0}, {0, s->height}, {s->width, s->height}}; // only true for rectangle shapes
 162     int d[4][2]={{0,0}, {0,0}, {0,0}, {0,0}};
 163     int sprite_ref[4][2];
 164     int virtual_ref[2][2];
 165     int w2, h2, w3, h3;
 166     int alpha=0, beta=0;
 167     int w= s->width;
 168     int h= s->height;
 169     int min_ab;
 170
 171     for(i=0; i<s->num_sprite_warping_points; i++){
 172         int length;
 173         int x=0, y=0;
 174
 175         length= get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 176         if(length){
 177             x= get_xbits(gb, length);
 178         }
 179         if(!(s->divx_version==500 && s->divx_build==413)) skip_bits1(gb); /* marker bit */
 180
 181         length= get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 182         if(length){
 183             y=get_xbits(gb, length);
 184         }
 185         skip_bits1(gb); /* marker bit */
 186         s->sprite_traj[i][0]= d[i][0]= x;
 187         s->sprite_traj[i][1]= d[i][1]= y;
 188     }
 189     for(; i<4; i++)
 190         s->sprite_traj[i][0]= s->sprite_traj[i][1]= 0;
 191
 192     while((1<<alpha)<w) alpha++;
 193     while((1<<beta )<h) beta++; // there seems to be a typo in the mpeg4 std for the definition of w' and h'
 194     w2= 1<<alpha;
 195     h2= 1<<beta;
 196
 197 // Note, the 4th point isn't used for GMC
 198     if(s->divx_version==500 && s->divx_build==413){
 199         sprite_ref[0][0]= a*vop_ref[0][0] + d[0][0];
 200         sprite_ref[0][1]= a*vop_ref[0][1] + d[0][1];
 201         sprite_ref[1][0]= a*vop_ref[1][0] + d[0][0] + d[1][0];
 202         sprite_ref[1][1]= a*vop_ref[1][1] + d[0][1] + d[1][1];
 203         sprite_ref[2][0]= a*vop_ref[2][0] + d[0][0] + d[2][0];
 204         sprite_ref[2][1]= a*vop_ref[2][1] + d[0][1] + d[2][1];
 205     } else {
 206         sprite_ref[0][0]= (a>>1)*(2*vop_ref[0][0] + d[0][0]);
 207         sprite_ref[0][1]= (a>>1)*(2*vop_ref[0][1] + d[0][1]);
 208         sprite_ref[1][0]= (a>>1)*(2*vop_ref[1][0] + d[0][0] + d[1][0]);
 209         sprite_ref[1][1]= (a>>1)*(2*vop_ref[1][1] + d[0][1] + d[1][1]);
 210         sprite_ref[2][0]= (a>>1)*(2*vop_ref[2][0] + d[0][0] + d[2][0]);
 211         sprite_ref[2][1]= (a>>1)*(2*vop_ref[2][1] + d[0][1] + d[2][1]);
 212     }
 213 /*    sprite_ref[3][0]= (a>>1)*(2*vop_ref[3][0] + d[0][0] + d[1][0] + d[2][0] + d[3][0]);
 214     sprite_ref[3][1]= (a>>1)*(2*vop_ref[3][1] + d[0][1] + d[1][1] + d[2][1] + d[3][1]); */
 215
 216 // this is mostly identical to the mpeg4 std (and is totally unreadable because of that ...)
 217 // perhaps it should be reordered to be more readable ...
 218 // the idea behind this virtual_ref mess is to be able to use shifts later per pixel instead of divides
 219 // so the distance between points is converted from w&h based to w2&h2 based which are of the 2^x form
 220     virtual_ref[0][0]= 16*(vop_ref[0][0] + w2)
 221         + 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);
 222     virtual_ref[0][1]= 16*vop_ref[0][1]
 223         + 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);
 224     virtual_ref[1][0]= 16*vop_ref[0][0]
 225         + 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);
 226     virtual_ref[1][1]= 16*(vop_ref[0][1] + h2)
 227         + 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);
 228
 229     switch(s->num_sprite_warping_points)
 230     {
 231         case 0:
 232             s->sprite_offset[0][0]= 0;
 233             s->sprite_offset[0][1]= 0;
 234             s->sprite_offset[1][0]= 0;
 235             s->sprite_offset[1][1]= 0;
 236             s->sprite_delta[0][0]= a;
 237             s->sprite_delta[0][1]= 0;
 238             s->sprite_delta[1][0]= 0;
 239             s->sprite_delta[1][1]= a;
 240             s->sprite_shift[0]= 0;
 241             s->sprite_shift[1]= 0;
 242             break;
 243         case 1: //GMC only
 244             s->sprite_offset[0][0]= sprite_ref[0][0] - a*vop_ref[0][0];
 245             s->sprite_offset[0][1]= sprite_ref[0][1] - a*vop_ref[0][1];
 246             s->sprite_offset[1][0]= ((sprite_ref[0][0]>>1)|(sprite_ref[0][0]&1)) - a*(vop_ref[0][0]/2);
 247             s->sprite_offset[1][1]= ((sprite_ref[0][1]>>1)|(sprite_ref[0][1]&1)) - a*(vop_ref[0][1]/2);
 248             s->sprite_delta[0][0]= a;
 249             s->sprite_delta[0][1]= 0;
 250             s->sprite_delta[1][0]= 0;
 251             s->sprite_delta[1][1]= a;
 252             s->sprite_shift[0]= 0;
 253             s->sprite_shift[1]= 0;
 254             break;
 255         case 2:
 256             s->sprite_offset[0][0]= (sprite_ref[0][0]<<(alpha+rho))
 257                                                   + (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-vop_ref[0][0])
 258                                                   + ( r*sprite_ref[0][1] - virtual_ref[0][1])*(-vop_ref[0][1])
 259                                                   + (1<<(alpha+rho-1));
 260             s->sprite_offset[0][1]= (sprite_ref[0][1]<<(alpha+rho))
 261                                                   + (-r*sprite_ref[0][1] + virtual_ref[0][1])*(-vop_ref[0][0])
 262                                                   + (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-vop_ref[0][1])
 263                                                   + (1<<(alpha+rho-1));
 264             s->sprite_offset[1][0]= ( (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-2*vop_ref[0][0] + 1)
 265                                      +( r*sprite_ref[0][1] - virtual_ref[0][1])*(-2*vop_ref[0][1] + 1)
 266                                      +2*w2*r*sprite_ref[0][0]
 267                                      - 16*w2
 268                                      + (1<<(alpha+rho+1)));
 269             s->sprite_offset[1][1]= ( (-r*sprite_ref[0][1] + virtual_ref[0][1])*(-2*vop_ref[0][0] + 1)
 270                                      +(-r*sprite_ref[0][0] + virtual_ref[0][0])*(-2*vop_ref[0][1] + 1)
 271                                      +2*w2*r*sprite_ref[0][1]
 272                                      - 16*w2
 273                                      + (1<<(alpha+rho+1)));
 274             s->sprite_delta[0][0]=   (-r*sprite_ref[0][0] + virtual_ref[0][0]);
 275             s->sprite_delta[0][1]=   (+r*sprite_ref[0][1] - virtual_ref[0][1]);
 276             s->sprite_delta[1][0]=   (-r*sprite_ref[0][1] + virtual_ref[0][1]);
 277             s->sprite_delta[1][1]=   (-r*sprite_ref[0][0] + virtual_ref[0][0]);
 278
 279             s->sprite_shift[0]= alpha+rho;
 280             s->sprite_shift[1]= alpha+rho+2;
 281             break;
 282         case 3:
 283             min_ab= FFMIN(alpha, beta);
 284             w3= w2>>min_ab;
 285             h3= h2>>min_ab;
 286             s->sprite_offset[0][0]=  (sprite_ref[0][0]<<(alpha+beta+rho-min_ab))
 287                                    + (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3*(-vop_ref[0][0])
 288                                    + (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3*(-vop_ref[0][1])
 289                                    + (1<<(alpha+beta+rho-min_ab-1));
 290             s->sprite_offset[0][1]=  (sprite_ref[0][1]<<(alpha+beta+rho-min_ab))
 291                                    + (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3*(-vop_ref[0][0])
 292                                    + (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3*(-vop_ref[0][1])
 293                                    + (1<<(alpha+beta+rho-min_ab-1));
 294             s->sprite_offset[1][0]=  (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3*(-2*vop_ref[0][0] + 1)
 295                                    + (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3*(-2*vop_ref[0][1] + 1)
 296                                    + 2*w2*h3*r*sprite_ref[0][0]
 297                                    - 16*w2*h3
 298                                    + (1<<(alpha+beta+rho-min_ab+1));
 299             s->sprite_offset[1][1]=  (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3*(-2*vop_ref[0][0] + 1)
 300                                    + (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3*(-2*vop_ref[0][1] + 1)
 301                                    + 2*w2*h3*r*sprite_ref[0][1]
 302                                    - 16*w2*h3
 303                                    + (1<<(alpha+beta+rho-min_ab+1));
 304             s->sprite_delta[0][0]=   (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3;
 305             s->sprite_delta[0][1]=   (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3;
 306             s->sprite_delta[1][0]=   (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3;
 307             s->sprite_delta[1][1]=   (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3;
 308
 309             s->sprite_shift[0]= alpha + beta + rho - min_ab;
 310             s->sprite_shift[1]= alpha + beta + rho - min_ab + 2;
 311             break;
 312     }
 313     /* try to simplify the situation */
 314     if(   s->sprite_delta[0][0] == a<<s->sprite_shift[0]
 315        && s->sprite_delta[0][1] == 0
 316        && s->sprite_delta[1][0] == 0
 317        && s->sprite_delta[1][1] == a<<s->sprite_shift[0])
 318     {
 319         s->sprite_offset[0][0]>>=s->sprite_shift[0];
 320         s->sprite_offset[0][1]>>=s->sprite_shift[0];
 321         s->sprite_offset[1][0]>>=s->sprite_shift[1];
 322         s->sprite_offset[1][1]>>=s->sprite_shift[1];
 323         s->sprite_delta[0][0]= a;
 324         s->sprite_delta[0][1]= 0;
 325         s->sprite_delta[1][0]= 0;
 326         s->sprite_delta[1][1]= a;
 327         s->sprite_shift[0]= 0;
 328         s->sprite_shift[1]= 0;
 329         s->real_sprite_warping_points=1;
 330     }
 331     else{
 332         int shift_y= 16 - s->sprite_shift[0];
 333         int shift_c= 16 - s->sprite_shift[1];
 334         for(i=0; i<2; i++){
 335             s->sprite_offset[0][i]<<= shift_y;
 336             s->sprite_offset[1][i]<<= shift_c;
 337             s->sprite_delta[0][i]<<= shift_y;
 338             s->sprite_delta[1][i]<<= shift_y;
 339             s->sprite_shift[i]= 16;
 340         }
 341         s->real_sprite_warping_points= s->num_sprite_warping_points;
 342     }
 343 }
 344
 345 /**
 346  * decodes the next video packet.
 347  * @return <0 if something went wrong
 348  */
 349 int mpeg4_decode_video_packet_header(MpegEncContext *s)
 350 {
 351     int mb_num_bits= av_log2(s->mb_num - 1) + 1;
 352     int header_extension=0, mb_num, len;
 353
 354     /* is there enough space left for a video packet + header */
 355     if( get_bits_count(&s->gb) > s->gb.size_in_bits-20) return -1;
 356
 357     for(len=0; len<32; len++){
 358         if(get_bits1(&s->gb)) break;
 359     }
 360
 361     if(len!=ff_mpeg4_get_video_packet_prefix_length(s)){
 362         av_log(s->avctx, AV_LOG_ERROR, "marker does not match f_code\n");
 363         return -1;
 364     }
 365
 366     if(s->shape != RECT_SHAPE){
 367         header_extension= get_bits1(&s->gb);
 368         //FIXME more stuff here
 369     }
 370
 371     mb_num= get_bits(&s->gb, mb_num_bits);
 372     if(mb_num>=s->mb_num){
 373         av_log(s->avctx, AV_LOG_ERROR, "illegal mb_num in video packet (%d %d) \n", mb_num, s->mb_num);
 374         return -1;
 375     }
 376     if(s->pict_type == FF_B_TYPE){
 377         int mb_x = 0, mb_y = 0;
 378
 379         while(s->next_picture.mbskip_table[ s->mb_index2xy[ mb_num ] ]) {
 380             if (!mb_x) ff_thread_await_progress((AVFrame*)s->next_picture_ptr, mb_y++, 0);
 381             mb_num++;
 382             if (++mb_x == s->mb_width) mb_x = 0;
 383         }
 384         if(mb_num >= s->mb_num) return -1; // slice contains just skipped MBs which where already decoded
 385     }
 386
 387     s->mb_x= mb_num % s->mb_width;
 388     s->mb_y= mb_num / s->mb_width;
 389
 390     if(s->shape != BIN_ONLY_SHAPE){
 391         int qscale= get_bits(&s->gb, s->quant_precision);
 392         if(qscale)
 393             s->chroma_qscale=s->qscale= qscale;
 394     }
 395
 396     if(s->shape == RECT_SHAPE){
 397         header_extension= get_bits1(&s->gb);
 398     }
 399     if(header_extension){
 400         int time_increment;
 401         int time_incr=0;
 402
 403         while (get_bits1(&s->gb) != 0)
 404             time_incr++;
 405
 406         check_marker(&s->gb, "before time_increment in video packed header");
 407         time_increment= get_bits(&s->gb, s->time_increment_bits);
 408         check_marker(&s->gb, "before vop_coding_type in video packed header");
 409
 410         skip_bits(&s->gb, 2); /* vop coding type */
 411         //FIXME not rect stuff here
 412
 413         if(s->shape != BIN_ONLY_SHAPE){
 414             skip_bits(&s->gb, 3); /* intra dc vlc threshold */
 415 //FIXME don't just ignore everything
 416             if(s->pict_type == FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE){
 417                 mpeg4_decode_sprite_trajectory(s, &s->gb);
 418                 av_log(s->avctx, AV_LOG_ERROR, "untested\n");
 419             }
 420
 421             //FIXME reduced res stuff here
 422
 423             if (s->pict_type != FF_I_TYPE) {
 424                 int f_code = get_bits(&s->gb, 3);       /* fcode_for */
 425                 if(f_code==0){
 426                     av_log(s->avctx, AV_LOG_ERROR, "Error, video packet header damaged (f_code=0)\n");
 427                 }
 428             }
 429             if (s->pict_type == FF_B_TYPE) {
 430                 int b_code = get_bits(&s->gb, 3);
 431                 if(b_code==0){
 432                     av_log(s->avctx, AV_LOG_ERROR, "Error, video packet header damaged (b_code=0)\n");
 433                 }
 434             }
 435         }
 436     }
 437     //FIXME new-pred stuff
 438
 439     return 0;
 440 }
 441
 442 /**
 443  * gets the average motion vector for a GMC MB.
 444  * @param n either 0 for the x component or 1 for y
 445  * @return the average MV for a GMC MB
 446  */
 447 static inline int get_amv(MpegEncContext *s, int n){
 448     int x, y, mb_v, sum, dx, dy, shift;
 449     int len = 1 << (s->f_code + 4);
 450     const int a= s->sprite_warping_accuracy;
 451
 452     if(s->workaround_bugs & FF_BUG_AMV)
 453         len >>= s->quarter_sample;
 454
 455     if(s->real_sprite_warping_points==1){
 456         if(s->divx_version==500 && s->divx_build==413)
 457             sum= s->sprite_offset[0][n] / (1<<(a - s->quarter_sample));
 458         else
 459             sum= RSHIFT(s->sprite_offset[0][n]<<s->quarter_sample, a);
 460     }else{
 461         dx= s->sprite_delta[n][0];
 462         dy= s->sprite_delta[n][1];
 463         shift= s->sprite_shift[0];
 464         if(n) dy -= 1<<(shift + a + 1);
 465         else  dx -= 1<<(shift + a + 1);
 466         mb_v= s->sprite_offset[0][n] + dx*s->mb_x*16 + dy*s->mb_y*16;
 467
 468         sum=0;
 469         for(y=0; y<16; y++){
 470             int v;
 471
 472             v= mb_v + dy*y;
 473             //XXX FIXME optimize
 474             for(x=0; x<16; x++){
 475                 sum+= v>>shift;
 476                 v+= dx;
 477             }
 478         }
 479         sum= RSHIFT(sum, a+8-s->quarter_sample);
 480     }
 481
 482     if      (sum < -len) sum= -len;
 483     else if (sum >= len) sum= len-1;
 484
 485     return sum;
 486 }
 487
 488 /**
 489  * decodes the dc value.
 490  * @param n block index (0-3 are luma, 4-5 are chroma)
 491  * @param dir_ptr the prediction direction will be stored here
 492  * @return the quantized dc
 493  */
 494 static inline int mpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr)
 495 {
 496     int level, code;
 497
 498     if (n < 4)
 499         code = get_vlc2(&s->gb, dc_lum.table, DC_VLC_BITS, 1);
 500     else
 501         code = get_vlc2(&s->gb, dc_chrom.table, DC_VLC_BITS, 1);
 502     if (code < 0 || code > 9 /* && s->nbit<9 */){
 503         av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
 504         return -1;
 505     }
 506     if (code == 0) {
 507         level = 0;
 508     } else {
 509         if(IS_3IV1){
 510             if(code==1)
 511                 level= 2*get_bits1(&s->gb)-1;
 512             else{
 513                 if(get_bits1(&s->gb))
 514                     level = get_bits(&s->gb, code-1) + (1<<(code-1));
 515                 else
 516                     level = -get_bits(&s->gb, code-1) - (1<<(code-1));
 517             }
 518         }else{
 519             level = get_xbits(&s->gb, code);
 520         }
 521
 522         if (code > 8){
 523             if(get_bits1(&s->gb)==0){ /* marker */
 524                 if(s->error_recognition>=2){
 525                     av_log(s->avctx, AV_LOG_ERROR, "dc marker bit missing\n");
 526                     return -1;
 527                 }
 528             }
 529         }
 530     }
 531
 532     return ff_mpeg4_pred_dc(s, n, level, dir_ptr, 0);
 533 }
 534
 535 /**
 536  * decodes first partition.
 537  * @return number of MBs decoded or <0 if an error occurred
 538  */
 539 static int mpeg4_decode_partition_a(MpegEncContext *s){
 540     int mb_num;
 541     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 542
 543     /* decode first partition */
 544     mb_num=0;
 545     s->first_slice_line=1;
 546     for(; s->mb_y<s->mb_height; s->mb_y++){
 547         ff_init_block_index(s);
 548         for(; s->mb_x<s->mb_width; s->mb_x++){
 549             const int xy= s->mb_x + s->mb_y*s->mb_stride;
 550             int cbpc;
 551             int dir=0;
 552
 553             mb_num++;
 554             ff_update_block_index(s);
 555             if(s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y+1)
 556                 s->first_slice_line=0;
 557
 558             if(s->pict_type==FF_I_TYPE){
 559                 int i;
 560
 561                 do{
 562                     if(show_bits_long(&s->gb, 19)==DC_MARKER){
 563                         return mb_num-1;
 564                     }
 565
 566                     cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 567                     if (cbpc < 0){
 568                         av_log(s->avctx, AV_LOG_ERROR, "cbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 569                         return -1;
 570                     }
 571                 }while(cbpc == 8);
 572
 573                 s->cbp_table[xy]= cbpc & 3;
 574                 s->current_picture.mb_type[xy]= MB_TYPE_INTRA;
 575                 s->mb_intra = 1;
 576
 577                 if(cbpc & 4) {
 578                     ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 579                 }
 580                 s->current_picture.qscale_table[xy]= s->qscale;
 581
 582                 s->mbintra_table[xy]= 1;
 583                 for(i=0; i<6; i++){
 584                     int dc_pred_dir;
 585                     int dc= mpeg4_decode_dc(s, i, &dc_pred_dir);
 586                     if(dc < 0){
 587                         av_log(s->avctx, AV_LOG_ERROR, "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 588                         return -1;
 589                     }
 590                     dir<<=1;
 591                     if(dc_pred_dir) dir|=1;
 592                 }
 593                 s->pred_dir_table[xy]= dir;
 594             }else{ /* P/S_TYPE */
 595                 int mx, my, pred_x, pred_y, bits;
 596                 int16_t * const mot_val= s->current_picture.motion_val[0][s->block_index[0]];
 597                 const int stride= s->b8_stride*2;
 598
 599 try_again:
 600                 bits= show_bits(&s->gb, 17);
 601                 if(bits==MOTION_MARKER){
 602                     return mb_num-1;
 603                 }
 604                 skip_bits1(&s->gb);
 605                 if(bits&0x10000){
 606                     /* skip mb */
 607                     if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE){
 608                         s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_GMC | MB_TYPE_L0;
 609                         mx= get_amv(s, 0);
 610                         my= get_amv(s, 1);
 611                     }else{
 612                         s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 613                         mx=my=0;
 614                     }
 615                     mot_val[0       ]= mot_val[2       ]=
 616                     mot_val[0+stride]= mot_val[2+stride]= mx;
 617                     mot_val[1       ]= mot_val[3       ]=
 618                     mot_val[1+stride]= mot_val[3+stride]= my;
 619
 620                     if(s->mbintra_table[xy])
 621                         ff_clean_intra_table_entries(s);
 622                     continue;
 623                 }
 624
 625                 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 626                 if (cbpc < 0){
 627                     av_log(s->avctx, AV_LOG_ERROR, "cbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 628                     return -1;
 629                 }
 630                 if(cbpc == 20)
 631                     goto try_again;
 632
 633                 s->cbp_table[xy]= cbpc&(8+3); //8 is dquant
 634
 635                 s->mb_intra = ((cbpc & 4) != 0);
 636
 637                 if(s->mb_intra){
 638                     s->current_picture.mb_type[xy]= MB_TYPE_INTRA;
 639                     s->mbintra_table[xy]= 1;
 640                     mot_val[0       ]= mot_val[2       ]=
 641                     mot_val[0+stride]= mot_val[2+stride]= 0;
 642                     mot_val[1       ]= mot_val[3       ]=
 643                     mot_val[1+stride]= mot_val[3+stride]= 0;
 644                 }else{
 645                     if(s->mbintra_table[xy])
 646                         ff_clean_intra_table_entries(s);
 647
 648                     if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE && (cbpc & 16) == 0)
 649                         s->mcsel= get_bits1(&s->gb);
 650                     else s->mcsel= 0;
 651
 652                     if ((cbpc & 16) == 0) {
 653                         /* 16x16 motion prediction */
 654
 655                         h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 656                         if(!s->mcsel){
 657                             mx = h263_decode_motion(s, pred_x, s->f_code);
 658                             if (mx >= 0xffff)
 659                                 return -1;
 660
 661                             my = h263_decode_motion(s, pred_y, s->f_code);
 662                             if (my >= 0xffff)
 663                                 return -1;
 664                             s->current_picture.mb_type[xy]= MB_TYPE_16x16 | MB_TYPE_L0;
 665                         } else {
 666                             mx = get_amv(s, 0);
 667                             my = get_amv(s, 1);
 668                             s->current_picture.mb_type[xy]= MB_TYPE_16x16 | MB_TYPE_GMC | MB_TYPE_L0;
 669                         }
 670
 671                         mot_val[0       ]= mot_val[2       ] =
 672                         mot_val[0+stride]= mot_val[2+stride]= mx;
 673                         mot_val[1       ]= mot_val[3       ]=
 674                         mot_val[1+stride]= mot_val[3+stride]= my;
 675                     } else {
 676                         int i;
 677                         s->current_picture.mb_type[xy]= MB_TYPE_8x8 | MB_TYPE_L0;
 678                         for(i=0;i<4;i++) {
 679                             int16_t *mot_val= h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 680                             mx = h263_decode_motion(s, pred_x, s->f_code);
 681                             if (mx >= 0xffff)
 682                                 return -1;
 683
 684                             my = h263_decode_motion(s, pred_y, s->f_code);
 685                             if (my >= 0xffff)
 686                                 return -1;
 687                             mot_val[0] = mx;
 688                             mot_val[1] = my;
 689                         }
 690                     }
 691                 }
 692             }
 693         }
 694         s->mb_x= 0;
 695     }
 696
 697     return mb_num;
 698 }
 699
 700 /**
 701  * decode second partition.
 702  * @return <0 if an error occurred
 703  */
 704 static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count){
 705     int mb_num=0;
 706     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 707
 708     s->mb_x= s->resync_mb_x;
 709     s->first_slice_line=1;
 710     for(s->mb_y= s->resync_mb_y; mb_num < mb_count; s->mb_y++){
 711         ff_init_block_index(s);
 712         for(; mb_num < mb_count && s->mb_x<s->mb_width; s->mb_x++){
 713             const int xy= s->mb_x + s->mb_y*s->mb_stride;
 714
 715             mb_num++;
 716             ff_update_block_index(s);
 717             if(s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y+1)
 718                 s->first_slice_line=0;
 719
 720             if(s->pict_type==FF_I_TYPE){
 721                 int ac_pred= get_bits1(&s->gb);
 722                 int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 723                 if(cbpy<0){
 724                     av_log(s->avctx, AV_LOG_ERROR, "cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 725                     return -1;
 726                 }
 727
 728                 s->cbp_table[xy]|= cbpy<<2;
 729                 s->current_picture.mb_type[xy] |= ac_pred*MB_TYPE_ACPRED;
 730             }else{ /* P || S_TYPE */
 731                 if(IS_INTRA(s->current_picture.mb_type[xy])){
 732                     int dir=0,i;
 733                     int ac_pred = get_bits1(&s->gb);
 734                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 735
 736                     if(cbpy<0){
 737                         av_log(s->avctx, AV_LOG_ERROR, "I cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 738                         return -1;
 739                     }
 740
 741                     if(s->cbp_table[xy] & 8) {
 742                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 743                     }
 744                     s->current_picture.qscale_table[xy]= s->qscale;
 745
 746                     for(i=0; i<6; i++){
 747                         int dc_pred_dir;
 748                         int dc= mpeg4_decode_dc(s, i, &dc_pred_dir);
 749                         if(dc < 0){
 750                             av_log(s->avctx, AV_LOG_ERROR, "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 751                             return -1;
 752                         }
 753                         dir<<=1;
 754                         if(dc_pred_dir) dir|=1;
 755                     }
 756                     s->cbp_table[xy]&= 3; //remove dquant
 757                     s->cbp_table[xy]|= cbpy<<2;
 758                     s->current_picture.mb_type[xy] |= ac_pred*MB_TYPE_ACPRED;
 759                     s->pred_dir_table[xy]= dir;
 760                 }else if(IS_SKIP(s->current_picture.mb_type[xy])){
 761                     s->current_picture.qscale_table[xy]= s->qscale;
 762                     s->cbp_table[xy]= 0;
 763                 }else{
 764                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 765
 766                     if(cbpy<0){
 767                         av_log(s->avctx, AV_LOG_ERROR, "P cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 768                         return -1;
 769                     }
 770
 771                     if(s->cbp_table[xy] & 8) {
 772                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 773                     }
 774                     s->current_picture.qscale_table[xy]= s->qscale;
 775
 776                     s->cbp_table[xy]&= 3; //remove dquant
 777                     s->cbp_table[xy]|= (cbpy^0xf)<<2;
 778                 }
 779             }
 780         }
 781         if(mb_num >= mb_count) return 0;
 782         s->mb_x= 0;
 783     }
 784     return 0;
 785 }
 786
 787 /**
 788  * decodes the first & second partition
 789  * @return <0 if error (and sets error type in the error_status_table)
 790  */
 791 int ff_mpeg4_decode_partitions(MpegEncContext *s)
 792 {
 793     int mb_num;
 794     const int part_a_error= s->pict_type==FF_I_TYPE ? (DC_ERROR|MV_ERROR) : MV_ERROR;
 795     const int part_a_end  = s->pict_type==FF_I_TYPE ? (DC_END  |MV_END)   : MV_END;
 796
 797     mb_num= mpeg4_decode_partition_a(s);
 798     if(mb_num<0){
 799         ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, part_a_error);
 800         return -1;
 801     }
 802
 803     if(s->resync_mb_x + s->resync_mb_y*s->mb_width + mb_num > s->mb_num){
 804         av_log(s->avctx, AV_LOG_ERROR, "slice below monitor ...\n");
 805         ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, part_a_error);
 806         return -1;
 807     }
 808
 809     s->mb_num_left= mb_num;
 810
 811     if(s->pict_type==FF_I_TYPE){
 812         while(show_bits(&s->gb, 9) == 1)
 813             skip_bits(&s->gb, 9);
 814         if(get_bits_long(&s->gb, 19)!=DC_MARKER){
 815             av_log(s->avctx, AV_LOG_ERROR, "marker missing after first I partition at %d %d\n", s->mb_x, s->mb_y);
 816             return -1;
 817         }
 818     }else{
 819         while(show_bits(&s->gb, 10) == 1)
 820             skip_bits(&s->gb, 10);
 821         if(get_bits(&s->gb, 17)!=MOTION_MARKER){
 822             av_log(s->avctx, AV_LOG_ERROR, "marker missing after first P partition at %d %d\n", s->mb_x, s->mb_y);
 823             return -1;
 824         }
 825     }
 826     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, part_a_end);
 827
 828     if( mpeg4_decode_partition_b(s, mb_num) < 0){
 829         if(s->pict_type==FF_P_TYPE)
 830             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, DC_ERROR);
 831         return -1;
 832     }else{
 833         if(s->pict_type==FF_P_TYPE)
 834             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, DC_END);
 835     }
 836
 837     return 0;
 838 }
 839
 840 /**
 841  * decodes a block.
 842  * @return <0 if an error occurred
 843  */
 844 static inline int mpeg4_decode_block(MpegEncContext * s, DCTELEM * block,
 845                               int n, int coded, int intra, int rvlc)
 846 {
 847     int level, i, last, run;
 848     int dc_pred_dir;
 849     RLTable * rl;
 850     RL_VLC_ELEM * rl_vlc;
 851     const uint8_t * scan_table;
 852     int qmul, qadd;
 853
 854     //Note intra & rvlc should be optimized away if this is inlined
 855
 856     if(intra) {
 857       if(s->use_intra_dc_vlc){
 858         /* DC coef */
 859         if(s->partitioned_frame){
 860             level = s->dc_val[0][ s->block_index[n] ];
 861             if(n<4) level= FASTDIV((level + (s->y_dc_scale>>1)), s->y_dc_scale);
 862             else    level= FASTDIV((level + (s->c_dc_scale>>1)), s->c_dc_scale);
 863             dc_pred_dir= (s->pred_dir_table[s->mb_x + s->mb_y*s->mb_stride]<<n)&32;
 864         }else{
 865             level = mpeg4_decode_dc(s, n, &dc_pred_dir);
 866             if (level < 0)
 867                 return -1;
 868         }
 869         block[0] = level;
 870         i = 0;
 871       }else{
 872             i = -1;
 873             ff_mpeg4_pred_dc(s, n, 0, &dc_pred_dir, 0);
 874       }
 875       if (!coded)
 876           goto not_coded;
 877
 878       if(rvlc){
 879           rl = &rvlc_rl_intra;
 880           rl_vlc = rvlc_rl_intra.rl_vlc[0];
 881       }else{
 882           rl = &ff_mpeg4_rl_intra;
 883           rl_vlc = ff_mpeg4_rl_intra.rl_vlc[0];
 884       }
 885       if (s->ac_pred) {
 886           if (dc_pred_dir == 0)
 887               scan_table = s->intra_v_scantable.permutated; /* left */
 888           else
 889               scan_table = s->intra_h_scantable.permutated; /* top */
 890       } else {
 891             scan_table = s->intra_scantable.permutated;
 892       }
 893       qmul=1;
 894       qadd=0;
 895     } else {
 896         i = -1;
 897         if (!coded) {
 898             s->block_last_index[n] = i;
 899             return 0;
 900         }
 901         if(rvlc) rl = &rvlc_rl_inter;
 902         else     rl = &ff_h263_rl_inter;
 903
 904         scan_table = s->intra_scantable.permutated;
 905
 906         if(s->mpeg_quant){
 907             qmul=1;
 908             qadd=0;
 909             if(rvlc){
 910                 rl_vlc = rvlc_rl_inter.rl_vlc[0];
 911             }else{
 912                 rl_vlc = ff_h263_rl_inter.rl_vlc[0];
 913             }
 914         }else{
 915             qmul = s->qscale << 1;
 916             qadd = (s->qscale - 1) | 1;
 917             if(rvlc){
 918                 rl_vlc = rvlc_rl_inter.rl_vlc[s->qscale];
 919             }else{
 920                 rl_vlc = ff_h263_rl_inter.rl_vlc[s->qscale];
 921             }
 922         }
 923     }
 924   {
 925     OPEN_READER(re, &s->gb);
 926     for(;;) {
 927         UPDATE_CACHE(re, &s->gb);
 928         GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
 929         if (level==0) {
 930           /* escape */
 931           if(rvlc){
 932                 if(SHOW_UBITS(re, &s->gb, 1)==0){
 933                     av_log(s->avctx, AV_LOG_ERROR, "1. marker bit missing in rvlc esc\n");
 934                     return -1;
 935                 }; SKIP_CACHE(re, &s->gb, 1);
 936
 937                 last=  SHOW_UBITS(re, &s->gb, 1); SKIP_CACHE(re, &s->gb, 1);
 938                 run=   SHOW_UBITS(re, &s->gb, 6); LAST_SKIP_CACHE(re, &s->gb, 6);
 939                 SKIP_COUNTER(re, &s->gb, 1+1+6);
 940                 UPDATE_CACHE(re, &s->gb);
 941
 942                 if(SHOW_UBITS(re, &s->gb, 1)==0){
 943                     av_log(s->avctx, AV_LOG_ERROR, "2. marker bit missing in rvlc esc\n");
 944                     return -1;
 945                 }; SKIP_CACHE(re, &s->gb, 1);
 946
 947                 level= SHOW_UBITS(re, &s->gb, 11); SKIP_CACHE(re, &s->gb, 11);
 948
 949                 if(SHOW_UBITS(re, &s->gb, 5)!=0x10){
 950                     av_log(s->avctx, AV_LOG_ERROR, "reverse esc missing\n");
 951                     return -1;
 952                 }; SKIP_CACHE(re, &s->gb, 5);
 953
 954                 level=  level * qmul + qadd;
 955                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1); LAST_SKIP_CACHE(re, &s->gb, 1);
 956                 SKIP_COUNTER(re, &s->gb, 1+11+5+1);
 957
 958                 i+= run + 1;
 959                 if(last) i+=192;
 960           }else{
 961             int cache;
 962             cache= GET_CACHE(re, &s->gb);
 963
 964             if(IS_3IV1)
 965                 cache ^= 0xC0000000;
 966
 967             if (cache&0x80000000) {
 968                 if (cache&0x40000000) {
 969                     /* third escape */
 970                     SKIP_CACHE(re, &s->gb, 2);
 971                     last=  SHOW_UBITS(re, &s->gb, 1); SKIP_CACHE(re, &s->gb, 1);
 972                     run=   SHOW_UBITS(re, &s->gb, 6); LAST_SKIP_CACHE(re, &s->gb, 6);
 973                     SKIP_COUNTER(re, &s->gb, 2+1+6);
 974                     UPDATE_CACHE(re, &s->gb);
 975
 976                     if(IS_3IV1){
 977                         level= SHOW_SBITS(re, &s->gb, 12); LAST_SKIP_BITS(re, &s->gb, 12);
 978                     }else{
 979                         if(SHOW_UBITS(re, &s->gb, 1)==0){
 980                             av_log(s->avctx, AV_LOG_ERROR, "1. marker bit missing in 3. esc\n");
 981                             return -1;
 982                         }; SKIP_CACHE(re, &s->gb, 1);
 983
 984                         level= SHOW_SBITS(re, &s->gb, 12); SKIP_CACHE(re, &s->gb, 12);
 985
 986                         if(SHOW_UBITS(re, &s->gb, 1)==0){
 987                             av_log(s->avctx, AV_LOG_ERROR, "2. marker bit missing in 3. esc\n");
 988                             return -1;
 989                         }; LAST_SKIP_CACHE(re, &s->gb, 1);
 990
 991                         SKIP_COUNTER(re, &s->gb, 1+12+1);
 992                     }
 993
 994 #if 0
 995                     if(s->error_recognition >= FF_ER_COMPLIANT){
 996                         const int abs_level= FFABS(level);
 997                         if(abs_level<=MAX_LEVEL && run<=MAX_RUN){
 998                             const int run1= run - rl->max_run[last][abs_level] - 1;
 999                             if(abs_level <= rl->max_level[last][run]){
1000                                 av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, vlc encoding possible\n");
1001                                 return -1;
1002                             }
1003                             if(s->error_recognition > FF_ER_COMPLIANT){
1004                                 if(abs_level <= rl->max_level[last][run]*2){
1005                                     av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 1 encoding possible\n");
1006                                     return -1;
1007                                 }
1008                                 if(run1 >= 0 && abs_level <= rl->max_level[last][run1]){
1009                                     av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 2 encoding possible\n");
1010                                     return -1;
1011                                 }
1012                             }
1013                         }
1014                     }
1015 #endif
1016                     if (level>0) level= level * qmul + qadd;
1017                     else         level= level * qmul - qadd;
1018
1019                     if((unsigned)(level + 2048) > 4095){
1020                         if(s->error_recognition > FF_ER_COMPLIANT){
1021                             if(level > 2560 || level<-2560){
1022                                 av_log(s->avctx, AV_LOG_ERROR, "|level| overflow in 3. esc, qp=%d\n", s->qscale);
1023                                 return -1;
1024                             }
1025                         }
1026                         level= level<0 ? -2048 : 2047;
1027                     }
1028
1029                     i+= run + 1;
1030                     if(last) i+=192;
1031                 } else {
1032                     /* second escape */
1033                     SKIP_BITS(re, &s->gb, 2);
1034                     GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1035                     i+= run + rl->max_run[run>>7][level/qmul] +1; //FIXME opt indexing
1036                     level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1037                     LAST_SKIP_BITS(re, &s->gb, 1);
1038                 }
1039             } else {
1040                 /* first escape */
1041                 SKIP_BITS(re, &s->gb, 1);
1042                 GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1043                 i+= run;
1044                 level = level + rl->max_level[run>>7][(run-1)&63] * qmul;//FIXME opt indexing
1045                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1046                 LAST_SKIP_BITS(re, &s->gb, 1);
1047             }
1048           }
1049         } else {
1050             i+= run;
1051             level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1052             LAST_SKIP_BITS(re, &s->gb, 1);
1053         }
1054         if (i > 62){
1055             i-= 192;
1056             if(i&(~63)){
1057                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1058                 return -1;
1059             }
1060
1061             block[scan_table[i]] = level;
1062             break;
1063         }
1064
1065         block[scan_table[i]] = level;
1066     }
1067     CLOSE_READER(re, &s->gb);
1068   }
1069  not_coded:
1070     if (intra) {
1071         if(!s->use_intra_dc_vlc){
1072             block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0);
1073
1074             i -= i>>31; //if(i == -1) i=0;
1075         }
1076
1077         mpeg4_pred_ac(s, block, n, dc_pred_dir);
1078         if (s->ac_pred) {
1079             i = 63; /* XXX: not optimal */
1080         }
1081     }
1082     s->block_last_index[n] = i;
1083     return 0;
1084 }
1085
1086 /**
1087  * decode partition C of one MB.
1088  * @return <0 if an error occurred
1089  */
1090 static int mpeg4_decode_partitioned_mb(MpegEncContext *s, DCTELEM block[6][64])
1091 {
1092     int cbp, mb_type;
1093     const int xy= s->mb_x + s->mb_y*s->mb_stride;
1094
1095     mb_type= s->current_picture.mb_type[xy];
1096     cbp = s->cbp_table[xy];
1097
1098     s->use_intra_dc_vlc= s->qscale < s->intra_dc_threshold;
1099
1100     if(s->current_picture.qscale_table[xy] != s->qscale){
1101         ff_set_qscale(s, s->current_picture.qscale_table[xy] );
1102     }
1103
1104     if (s->pict_type == FF_P_TYPE || s->pict_type==FF_S_TYPE) {
1105         int i;
1106         for(i=0; i<4; i++){
1107             s->mv[0][i][0] = s->current_picture.motion_val[0][ s->block_index[i] ][0];
1108             s->mv[0][i][1] = s->current_picture.motion_val[0][ s->block_index[i] ][1];
1109         }
1110         s->mb_intra = IS_INTRA(mb_type);
1111
1112         if (IS_SKIP(mb_type)) {
1113             /* skip mb */
1114             for(i=0;i<6;i++)
1115                 s->block_last_index[i] = -1;
1116             s->mv_dir = MV_DIR_FORWARD;
1117             s->mv_type = MV_TYPE_16X16;
1118             if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE){
1119                 s->mcsel=1;
1120                 s->mb_skipped = 0;
1121             }else{
1122                 s->mcsel=0;
1123                 s->mb_skipped = 1;
1124             }
1125         }else if(s->mb_intra){
1126             s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1127         }else if(!s->mb_intra){
1128 //            s->mcsel= 0; //FIXME do we need to init that
1129
1130             s->mv_dir = MV_DIR_FORWARD;
1131             if (IS_8X8(mb_type)) {
1132                 s->mv_type = MV_TYPE_8X8;
1133             } else {
1134                 s->mv_type = MV_TYPE_16X16;
1135             }
1136         }
1137     } else { /* I-Frame */
1138         s->mb_intra = 1;
1139         s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1140     }
1141
1142     if (!IS_SKIP(mb_type)) {
1143         int i;
1144         s->dsp.clear_blocks(s->block[0]);
1145         /* decode each block */
1146         for (i = 0; i < 6; i++) {
1147             if(mpeg4_decode_block(s, block[i], i, cbp&32, s->mb_intra, s->rvlc) < 0){
1148                 av_log(s->avctx, AV_LOG_ERROR, "texture corrupted at %d %d %d\n", s->mb_x, s->mb_y, s->mb_intra);
1149                 return -1;
1150             }
1151             cbp+=cbp;
1152         }
1153     }
1154
1155     /* per-MB end of slice check */
1156
1157     if(--s->mb_num_left <= 0){
1158         if(mpeg4_is_resync(s))
1159             return SLICE_END;
1160         else
1161             return SLICE_NOEND;
1162     }else{
1163         if(mpeg4_is_resync(s)){
1164             const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1165             if(s->cbp_table[xy+delta])
1166                 return SLICE_END;
1167         }
1168         return SLICE_OK;
1169     }
1170 }
1171
1172 static int mpeg4_decode_mb(MpegEncContext *s,
1173                       DCTELEM block[6][64])
1174 {
1175     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
1176     int16_t *mot_val;
1177     static int8_t quant_tab[4] = { -1, -2, 1, 2 };
1178     const int xy= s->mb_x + s->mb_y * s->mb_stride;
1179
1180     assert(s->h263_pred);
1181
1182     if (s->pict_type == FF_P_TYPE || s->pict_type==FF_S_TYPE) {
1183         do{
1184             if (get_bits1(&s->gb)) {
1185                 /* skip mb */
1186                 s->mb_intra = 0;
1187                 for(i=0;i<6;i++)
1188                     s->block_last_index[i] = -1;
1189                 s->mv_dir = MV_DIR_FORWARD;
1190                 s->mv_type = MV_TYPE_16X16;
1191                 if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE){
1192                     s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_GMC | MB_TYPE_16x16 | MB_TYPE_L0;
1193                     s->mcsel=1;
1194                     s->mv[0][0][0]= get_amv(s, 0);
1195                     s->mv[0][0][1]= get_amv(s, 1);
1196
1197                     s->mb_skipped = 0;
1198                 }else{
1199                     s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
1200                     s->mcsel=0;
1201                     s->mv[0][0][0] = 0;
1202                     s->mv[0][0][1] = 0;
1203                     s->mb_skipped = 1;
1204                 }
1205                 goto end;
1206             }
1207             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
1208             if (cbpc < 0){
1209                 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1210                 return -1;
1211             }
1212         }while(cbpc == 20);
1213
1214         s->dsp.clear_blocks(s->block[0]);
1215         dquant = cbpc & 8;
1216         s->mb_intra = ((cbpc & 4) != 0);
1217         if (s->mb_intra) goto intra;
1218
1219         if(s->pict_type==FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE && (cbpc & 16) == 0)
1220             s->mcsel= get_bits1(&s->gb);
1221         else s->mcsel= 0;
1222         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1) ^ 0x0F;
1223
1224         cbp = (cbpc & 3) | (cbpy << 2);
1225         if (dquant) {
1226             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1227         }
1228         if((!s->progressive_sequence) && (cbp || (s->workaround_bugs&FF_BUG_XVID_ILACE)))
1229             s->interlaced_dct= get_bits1(&s->gb);
1230
1231         s->mv_dir = MV_DIR_FORWARD;
1232         if ((cbpc & 16) == 0) {
1233             if(s->mcsel){
1234                 s->current_picture.mb_type[xy]= MB_TYPE_GMC | MB_TYPE_16x16 | MB_TYPE_L0;
1235                 /* 16x16 global motion prediction */
1236                 s->mv_type = MV_TYPE_16X16;
1237                 mx= get_amv(s, 0);
1238                 my= get_amv(s, 1);
1239                 s->mv[0][0][0] = mx;
1240                 s->mv[0][0][1] = my;
1241             }else if((!s->progressive_sequence) && get_bits1(&s->gb)){
1242                 s->current_picture.mb_type[xy]= MB_TYPE_16x8 | MB_TYPE_L0 | MB_TYPE_INTERLACED;
1243                 /* 16x8 field motion prediction */
1244                 s->mv_type= MV_TYPE_FIELD;
1245
1246                 s->field_select[0][0]= get_bits1(&s->gb);
1247                 s->field_select[0][1]= get_bits1(&s->gb);
1248
1249                 h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1250
1251                 for(i=0; i<2; i++){
1252                     mx = h263_decode_motion(s, pred_x, s->f_code);
1253                     if (mx >= 0xffff)
1254                         return -1;
1255
1256                     my = h263_decode_motion(s, pred_y/2, s->f_code);
1257                     if (my >= 0xffff)
1258                         return -1;
1259
1260                     s->mv[0][i][0] = mx;
1261                     s->mv[0][i][1] = my;
1262                 }
1263             }else{
1264                 s->current_picture.mb_type[xy]= MB_TYPE_16x16 | MB_TYPE_L0;
1265                 /* 16x16 motion prediction */
1266                 s->mv_type = MV_TYPE_16X16;
1267                 h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1268                 mx = h263_decode_motion(s, pred_x, s->f_code);
1269
1270                 if (mx >= 0xffff)
1271                     return -1;
1272
1273                 my = h263_decode_motion(s, pred_y, s->f_code);
1274
1275                 if (my >= 0xffff)
1276                     return -1;
1277                 s->mv[0][0][0] = mx;
1278                 s->mv[0][0][1] = my;
1279             }
1280         } else {
1281             s->current_picture.mb_type[xy]= MB_TYPE_8x8 | MB_TYPE_L0;
1282             s->mv_type = MV_TYPE_8X8;
1283             for(i=0;i<4;i++) {
1284                 mot_val = h263_pred_motion(s, i, 0, &pred_x, &pred_y);
1285                 mx = h263_decode_motion(s, pred_x, s->f_code);
1286                 if (mx >= 0xffff)
1287                     return -1;
1288
1289                 my = h263_decode_motion(s, pred_y, s->f_code);
1290                 if (my >= 0xffff)
1291                     return -1;
1292                 s->mv[0][i][0] = mx;
1293                 s->mv[0][i][1] = my;
1294                 mot_val[0] = mx;
1295                 mot_val[1] = my;
1296             }
1297         }
1298     } else if(s->pict_type==FF_B_TYPE) {
1299         int modb1; // first bit of modb
1300         int modb2; // second bit of modb
1301         int mb_type;
1302
1303         s->mb_intra = 0; //B-frames never contain intra blocks
1304         s->mcsel=0;      //     ...               true gmc blocks
1305
1306         if(s->mb_x==0){
1307             for(i=0; i<2; i++){
1308                 s->last_mv[i][0][0]=
1309                 s->last_mv[i][0][1]=
1310                 s->last_mv[i][1][0]=
1311                 s->last_mv[i][1][1]= 0;
1312             }
1313
1314             ff_thread_await_progress((AVFrame*)s->next_picture_ptr, s->mb_y, 0);
1315         }
1316
1317         /* if we skipped it in the future P Frame than skip it now too */
1318         s->mb_skipped= s->next_picture.mbskip_table[s->mb_y * s->mb_stride + s->mb_x]; // Note, skiptab=0 if last was GMC
1319
1320         if(s->mb_skipped){
1321                 /* skip mb */
1322             for(i=0;i<6;i++)
1323                 s->block_last_index[i] = -1;
1324
1325             s->mv_dir = MV_DIR_FORWARD;
1326             s->mv_type = MV_TYPE_16X16;
1327             s->mv[0][0][0] = 0;
1328             s->mv[0][0][1] = 0;
1329             s->mv[1][0][0] = 0;
1330             s->mv[1][0][1] = 0;
1331             s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
1332             goto end;
1333         }
1334
1335         modb1= get_bits1(&s->gb);
1336         if(modb1){
1337             mb_type= MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1; //like MB_TYPE_B_DIRECT but no vectors coded
1338             cbp=0;
1339         }else{
1340             modb2= get_bits1(&s->gb);
1341             mb_type= get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
1342             if(mb_type<0){
1343                 av_log(s->avctx, AV_LOG_ERROR, "illegal MB_type\n");
1344                 return -1;
1345             }
1346             mb_type= mb_type_b_map[ mb_type ];
1347             if(modb2) cbp= 0;
1348             else{
1349                 s->dsp.clear_blocks(s->block[0]);
1350                 cbp= get_bits(&s->gb, 6);
1351             }
1352
1353             if ((!IS_DIRECT(mb_type)) && cbp) {
1354                 if(get_bits1(&s->gb)){
1355                     ff_set_qscale(s, s->qscale + get_bits1(&s->gb)*4 - 2);
1356                 }
1357             }
1358
1359             if(!s->progressive_sequence){
1360                 if(cbp)
1361                     s->interlaced_dct= get_bits1(&s->gb);
1362
1363                 if(!IS_DIRECT(mb_type) && get_bits1(&s->gb)){
1364                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
1365                     mb_type &= ~MB_TYPE_16x16;
1366
1367                     if(USES_LIST(mb_type, 0)){
1368                         s->field_select[0][0]= get_bits1(&s->gb);
1369                         s->field_select[0][1]= get_bits1(&s->gb);
1370                     }
1371                     if(USES_LIST(mb_type, 1)){
1372                         s->field_select[1][0]= get_bits1(&s->gb);
1373                         s->field_select[1][1]= get_bits1(&s->gb);
1374                     }
1375                 }
1376             }
1377
1378             s->mv_dir = 0;
1379             if((mb_type & (MB_TYPE_DIRECT2|MB_TYPE_INTERLACED)) == 0){
1380                 s->mv_type= MV_TYPE_16X16;
1381
1382                 if(USES_LIST(mb_type, 0)){
1383                     s->mv_dir = MV_DIR_FORWARD;
1384
1385                     mx = h263_decode_motion(s, s->last_mv[0][0][0], s->f_code);
1386                     my = h263_decode_motion(s, s->last_mv[0][0][1], s->f_code);
1387                     s->last_mv[0][1][0]= s->last_mv[0][0][0]= s->mv[0][0][0] = mx;
1388                     s->last_mv[0][1][1]= s->last_mv[0][0][1]= s->mv[0][0][1] = my;
1389                 }
1390
1391                 if(USES_LIST(mb_type, 1)){
1392                     s->mv_dir |= MV_DIR_BACKWARD;
1393
1394                     mx = h263_decode_motion(s, s->last_mv[1][0][0], s->b_code);
1395                     my = h263_decode_motion(s, s->last_mv[1][0][1], s->b_code);
1396                     s->last_mv[1][1][0]= s->last_mv[1][0][0]= s->mv[1][0][0] = mx;
1397                     s->last_mv[1][1][1]= s->last_mv[1][0][1]= s->mv[1][0][1] = my;
1398                 }
1399             }else if(!IS_DIRECT(mb_type)){
1400                 s->mv_type= MV_TYPE_FIELD;
1401
1402                 if(USES_LIST(mb_type, 0)){
1403                     s->mv_dir = MV_DIR_FORWARD;
1404
1405                     for(i=0; i<2; i++){
1406                         mx = h263_decode_motion(s, s->last_mv[0][i][0]  , s->f_code);
1407                         my = h263_decode_motion(s, s->last_mv[0][i][1]/2, s->f_code);
1408                         s->last_mv[0][i][0]=  s->mv[0][i][0] = mx;
1409                         s->last_mv[0][i][1]= (s->mv[0][i][1] = my)*2;
1410                     }
1411                 }
1412
1413                 if(USES_LIST(mb_type, 1)){
1414                     s->mv_dir |= MV_DIR_BACKWARD;
1415
1416                     for(i=0; i<2; i++){
1417                         mx = h263_decode_motion(s, s->last_mv[1][i][0]  , s->b_code);
1418                         my = h263_decode_motion(s, s->last_mv[1][i][1]/2, s->b_code);
1419                         s->last_mv[1][i][0]=  s->mv[1][i][0] = mx;
1420                         s->last_mv[1][i][1]= (s->mv[1][i][1] = my)*2;
1421                     }
1422                 }
1423             }
1424         }
1425
1426         if(IS_DIRECT(mb_type)){
1427             if(IS_SKIP(mb_type))
1428                 mx=my=0;
1429             else{
1430                 mx = h263_decode_motion(s, 0, 1);
1431                 my = h263_decode_motion(s, 0, 1);
1432             }
1433
1434             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
1435             mb_type |= ff_mpeg4_set_direct_mv(s, mx, my);
1436         }
1437         s->current_picture.mb_type[xy]= mb_type;
1438     } else { /* I-Frame */
1439         do{
1440             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
1441             if (cbpc < 0){
1442                 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1443                 return -1;
1444             }
1445         }while(cbpc == 8);
1446
1447         dquant = cbpc & 4;
1448         s->mb_intra = 1;
1449 intra:
1450         s->ac_pred = get_bits1(&s->gb);
1451         if(s->ac_pred)
1452             s->current_picture.mb_type[xy]= MB_TYPE_INTRA | MB_TYPE_ACPRED;
1453         else
1454             s->current_picture.mb_type[xy]= MB_TYPE_INTRA;
1455
1456         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
1457         if(cbpy<0){
1458             av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
1459             return -1;
1460         }
1461         cbp = (cbpc & 3) | (cbpy << 2);
1462
1463         s->use_intra_dc_vlc= s->qscale < s->intra_dc_threshold;
1464
1465         if (dquant) {
1466             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1467         }
1468
1469         if(!s->progressive_sequence)
1470             s->interlaced_dct= get_bits1(&s->gb);
1471
1472         s->dsp.clear_blocks(s->block[0]);
1473         /* decode each block */
1474         for (i = 0; i < 6; i++) {
1475             if (mpeg4_decode_block(s, block[i], i, cbp&32, 1, 0) < 0)
1476                 return -1;
1477             cbp+=cbp;
1478         }
1479         goto end;
1480     }
1481
1482     /* decode each block */
1483     for (i = 0; i < 6; i++) {
1484         if (mpeg4_decode_block(s, block[i], i, cbp&32, 0, 0) < 0)
1485             return -1;
1486         cbp+=cbp;
1487     }
1488 end:
1489
1490         /* per-MB end of slice check */
1491     if(s->codec_id==CODEC_ID_MPEG4){
1492         if(mpeg4_is_resync(s)){
1493             const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1494
1495             if(s->pict_type==FF_B_TYPE){
1496                 ff_thread_await_progress((AVFrame*)s->next_picture_ptr,
1497                                         (s->mb_x + delta >= s->mb_width) ? FFMIN(s->mb_y+1, s->mb_height-1) : s->mb_y, 0);
1498             }
1499
1500             if(s->pict_type==FF_B_TYPE && s->next_picture.mbskip_table[xy + delta])
1501                 return SLICE_OK;
1502             return SLICE_END;
1503         }
1504     }
1505
1506     return SLICE_OK;
1507 }
1508
1509
1510 static int mpeg4_decode_gop_header(MpegEncContext * s, GetBitContext *gb){
1511     int hours, minutes, seconds;
1512
1513     if(!show_bits(gb, 23)){
1514         av_log(s->avctx, AV_LOG_WARNING, "GOP header invalid\n");
1515         return -1;
1516     }
1517
1518     hours= get_bits(gb, 5);
1519     minutes= get_bits(gb, 6);
1520     skip_bits1(gb);
1521     seconds= get_bits(gb, 6);
1522
1523     s->time_base= seconds + 60*(minutes + 60*hours);
1524
1525     skip_bits1(gb);
1526     skip_bits1(gb);
1527
1528     return 0;
1529 }
1530
1531 static int decode_vol_header(MpegEncContext *s, GetBitContext *gb){
1532     int width, height, vo_ver_id;
1533
1534     /* vol header */
1535     skip_bits(gb, 1); /* random access */
1536     s->vo_type= get_bits(gb, 8);
1537     if (get_bits1(gb) != 0) { /* is_ol_id */
1538         vo_ver_id = get_bits(gb, 4); /* vo_ver_id */
1539         skip_bits(gb, 3); /* vo_priority */
1540     } else {
1541         vo_ver_id = 1;
1542     }
1543     s->aspect_ratio_info= get_bits(gb, 4);
1544     if(s->aspect_ratio_info == FF_ASPECT_EXTENDED){
1545         s->avctx->sample_aspect_ratio.num= get_bits(gb, 8); // par_width
1546         s->avctx->sample_aspect_ratio.den= get_bits(gb, 8); // par_height
1547     }else{
1548         s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1549     }
1550
1551     if ((s->vol_control_parameters=get_bits1(gb))) { /* vol control parameter */
1552         int chroma_format= get_bits(gb, 2);
1553         if(chroma_format!=CHROMA_420){
1554             av_log(s->avctx, AV_LOG_ERROR, "illegal chroma format\n");
1555         }
1556         s->low_delay= get_bits1(gb);
1557         if(get_bits1(gb)){ /* vbv parameters */
1558             get_bits(gb, 15);   /* first_half_bitrate */
1559             skip_bits1(gb);     /* marker */
1560             get_bits(gb, 15);   /* latter_half_bitrate */
1561             skip_bits1(gb);     /* marker */
1562             get_bits(gb, 15);   /* first_half_vbv_buffer_size */
1563             skip_bits1(gb);     /* marker */
1564             get_bits(gb, 3);    /* latter_half_vbv_buffer_size */
1565             get_bits(gb, 11);   /* first_half_vbv_occupancy */
1566             skip_bits1(gb);     /* marker */
1567             get_bits(gb, 15);   /* latter_half_vbv_occupancy */
1568             skip_bits1(gb);     /* marker */
1569         }
1570     }else{
1571         // set low delay flag only once the smartest? low delay detection won't be overriden
1572         if(s->picture_number==0)
1573             s->low_delay=0;
1574     }
1575
1576     s->shape = get_bits(gb, 2); /* vol shape */
1577     if(s->shape != RECT_SHAPE) av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
1578     if(s->shape == GRAY_SHAPE && vo_ver_id != 1){
1579         av_log(s->avctx, AV_LOG_ERROR, "Gray shape not supported\n");
1580         skip_bits(gb, 4);  //video_object_layer_shape_extension
1581     }
1582
1583     check_marker(gb, "before time_increment_resolution");
1584
1585     s->avctx->time_base.den = get_bits(gb, 16);
1586     if(!s->avctx->time_base.den){
1587         av_log(s->avctx, AV_LOG_ERROR, "time_base.den==0\n");
1588         s->avctx->time_base.num = 0;
1589         return -1;
1590     }
1591
1592     s->time_increment_bits = av_log2(s->avctx->time_base.den - 1) + 1;
1593     if (s->time_increment_bits < 1)
1594         s->time_increment_bits = 1;
1595
1596     check_marker(gb, "before fixed_vop_rate");
1597
1598     if (get_bits1(gb) != 0) {   /* fixed_vop_rate  */
1599         s->avctx->time_base.num = get_bits(gb, s->time_increment_bits);
1600     }else
1601         s->avctx->time_base.num = 1;
1602
1603     s->t_frame=0;
1604
1605     if (s->shape != BIN_ONLY_SHAPE) {
1606         if (s->shape == RECT_SHAPE) {
1607             skip_bits1(gb);   /* marker */
1608             width = get_bits(gb, 13);
1609             skip_bits1(gb);   /* marker */
1610             height = get_bits(gb, 13);
1611             skip_bits1(gb);   /* marker */
1612             if(width && height && !(s->width && s->codec_tag == AV_RL32("MP4S"))){ /* they should be non zero but who knows ... */
1613                 s->width = width;
1614                 s->height = height;
1615             }
1616         }
1617
1618         s->progressive_sequence=
1619         s->progressive_frame= get_bits1(gb)^1;
1620         s->interlaced_dct=0;
1621         if(!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
1622             av_log(s->avctx, AV_LOG_INFO, "MPEG4 OBMC not supported (very likely buggy encoder)\n");   /* OBMC Disable */
1623         if (vo_ver_id == 1) {
1624             s->vol_sprite_usage = get_bits1(gb); /* vol_sprite_usage */
1625         } else {
1626             s->vol_sprite_usage = get_bits(gb, 2); /* vol_sprite_usage */
1627         }
1628         if(s->vol_sprite_usage==STATIC_SPRITE) av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
1629         if(s->vol_sprite_usage==STATIC_SPRITE || s->vol_sprite_usage==GMC_SPRITE){
1630             if(s->vol_sprite_usage==STATIC_SPRITE){
1631                 s->sprite_width = get_bits(gb, 13);
1632                 skip_bits1(gb); /* marker */
1633                 s->sprite_height= get_bits(gb, 13);
1634                 skip_bits1(gb); /* marker */
1635                 s->sprite_left  = get_bits(gb, 13);
1636                 skip_bits1(gb); /* marker */
1637                 s->sprite_top   = get_bits(gb, 13);
1638                 skip_bits1(gb); /* marker */
1639             }
1640             s->num_sprite_warping_points= get_bits(gb, 6);
1641             if(s->num_sprite_warping_points > 3){
1642                 av_log(s->avctx, AV_LOG_ERROR, "%d sprite_warping_points\n", s->num_sprite_warping_points);
1643                 s->num_sprite_warping_points= 0;
1644                 return -1;
1645             }
1646             s->sprite_warping_accuracy = get_bits(gb, 2);
1647             s->sprite_brightness_change= get_bits1(gb);
1648             if(s->vol_sprite_usage==STATIC_SPRITE)
1649                 s->low_latency_sprite= get_bits1(gb);
1650         }
1651         // FIXME sadct disable bit if verid!=1 && shape not rect
1652
1653         if (get_bits1(gb) == 1) {   /* not_8_bit */
1654             s->quant_precision = get_bits(gb, 4); /* quant_precision */
1655             if(get_bits(gb, 4)!=8) av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n"); /* bits_per_pixel */
1656             if(s->quant_precision!=5) av_log(s->avctx, AV_LOG_ERROR, "quant precision %d\n", s->quant_precision);
1657         } else {
1658             s->quant_precision = 5;
1659         }
1660
1661         // FIXME a bunch of grayscale shape things
1662
1663         if((s->mpeg_quant=get_bits1(gb))){ /* vol_quant_type */
1664             int i, v;
1665
1666             /* load default matrixes */
1667             for(i=0; i<64; i++){
1668                 int j= s->dsp.idct_permutation[i];
1669                 v= ff_mpeg4_default_intra_matrix[i];
1670                 s->intra_matrix[j]= v;
1671                 s->chroma_intra_matrix[j]= v;
1672
1673                 v= ff_mpeg4_default_non_intra_matrix[i];
1674                 s->inter_matrix[j]= v;
1675                 s->chroma_inter_matrix[j]= v;
1676             }
1677
1678             /* load custom intra matrix */
1679             if(get_bits1(gb)){
1680                 int last=0;
1681                 for(i=0; i<64; i++){
1682                     int j;
1683                     v= get_bits(gb, 8);
1684                     if(v==0) break;
1685
1686                     last= v;
1687                     j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1688                     s->intra_matrix[j]= v;
1689                     s->chroma_intra_matrix[j]= v;
1690                 }
1691
1692                 /* replicate last value */
1693                 for(; i<64; i++){
1694                     int j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1695                     s->intra_matrix[j]= last;
1696                     s->chroma_intra_matrix[j]= last;
1697                 }
1698             }
1699
1700             /* load custom non intra matrix */
1701             if(get_bits1(gb)){
1702                 int last=0;
1703                 for(i=0; i<64; i++){
1704                     int j;
1705                     v= get_bits(gb, 8);
1706                     if(v==0) break;
1707
1708                     last= v;
1709                     j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1710                     s->inter_matrix[j]= v;
1711                     s->chroma_inter_matrix[j]= v;
1712                 }
1713
1714                 /* replicate last value */
1715                 for(; i<64; i++){
1716                     int j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1717                     s->inter_matrix[j]= last;
1718                     s->chroma_inter_matrix[j]= last;
1719                 }
1720             }
1721
1722             // FIXME a bunch of grayscale shape things
1723         }
1724
1725         if(vo_ver_id != 1)
1726              s->quarter_sample= get_bits1(gb);
1727         else s->quarter_sample=0;
1728
1729         if(!get_bits1(gb)){
1730             int pos= get_bits_count(gb);
1731             int estimation_method= get_bits(gb, 2);
1732             if(estimation_method<2){
1733                 if(!get_bits1(gb)){
1734                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //opaque
1735                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //transparent
1736                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //intra_cae
1737                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //inter_cae
1738                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //no_update
1739                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //upampling
1740                 }
1741                 if(!get_bits1(gb)){
1742                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //intra_blocks
1743                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //inter_blocks
1744                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //inter4v_blocks
1745                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //not coded blocks
1746                 }
1747                 if(!check_marker(gb, "in complexity estimation part 1")){
1748                     skip_bits_long(gb, pos - get_bits_count(gb));
1749                     goto no_cplx_est;
1750                 }
1751                 if(!get_bits1(gb)){
1752                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //dct_coeffs
1753                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //dct_lines
1754                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //vlc_syms
1755                     s->cplx_estimation_trash_i += 4*get_bits1(gb); //vlc_bits
1756                 }
1757                 if(!get_bits1(gb)){
1758                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //apm
1759                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //npm
1760                     s->cplx_estimation_trash_b += 8*get_bits1(gb); //interpolate_mc_q
1761                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //forwback_mc_q
1762                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //halfpel2
1763                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //halfpel4
1764                 }
1765                 if(!check_marker(gb, "in complexity estimation part 2")){
1766                     skip_bits_long(gb, pos - get_bits_count(gb));
1767                     goto no_cplx_est;
1768                 }
1769                 if(estimation_method==1){
1770                     s->cplx_estimation_trash_i += 8*get_bits1(gb); //sadct
1771                     s->cplx_estimation_trash_p += 8*get_bits1(gb); //qpel
1772                 }
1773             }else
1774                 av_log(s->avctx, AV_LOG_ERROR, "Invalid Complexity estimation method %d\n", estimation_method);
1775         }else{
1776 no_cplx_est:
1777             s->cplx_estimation_trash_i=
1778             s->cplx_estimation_trash_p=
1779             s->cplx_estimation_trash_b= 0;
1780         }
1781
1782         s->resync_marker= !get_bits1(gb); /* resync_marker_disabled */
1783
1784         s->data_partitioning= get_bits1(gb);
1785         if(s->data_partitioning){
1786             s->rvlc= get_bits1(gb);
1787         }
1788
1789         if(vo_ver_id != 1) {
1790             s->new_pred= get_bits1(gb);
1791             if(s->new_pred){
1792                 av_log(s->avctx, AV_LOG_ERROR, "new pred not supported\n");
1793                 skip_bits(gb, 2); /* requested upstream message type */
1794                 skip_bits1(gb); /* newpred segment type */
1795             }
1796             s->reduced_res_vop= get_bits1(gb);
1797             if(s->reduced_res_vop) av_log(s->avctx, AV_LOG_ERROR, "reduced resolution VOP not supported\n");
1798         }
1799         else{
1800             s->new_pred=0;
1801             s->reduced_res_vop= 0;
1802         }
1803
1804         s->scalability= get_bits1(gb);
1805
1806         if (s->scalability) {
1807             GetBitContext bak= *gb;
1808             int ref_layer_id;
1809             int ref_layer_sampling_dir;
1810             int h_sampling_factor_n;
1811             int h_sampling_factor_m;
1812             int v_sampling_factor_n;
1813             int v_sampling_factor_m;
1814
1815             s->hierachy_type= get_bits1(gb);
1816             ref_layer_id= get_bits(gb, 4);
1817             ref_layer_sampling_dir= get_bits1(gb);
1818             h_sampling_factor_n= get_bits(gb, 5);
1819             h_sampling_factor_m= get_bits(gb, 5);
1820             v_sampling_factor_n= get_bits(gb, 5);
1821             v_sampling_factor_m= get_bits(gb, 5);
1822             s->enhancement_type= get_bits1(gb);
1823
1824             if(   h_sampling_factor_n==0 || h_sampling_factor_m==0
1825                || v_sampling_factor_n==0 || v_sampling_factor_m==0){
1826                 /* illegal scalability header (VERY broken encoder),
1827                  * trying to workaround */
1828                 s->scalability=0;
1829                 *gb= bak;
1830             }else
1831                 av_log(s->avctx, AV_LOG_ERROR, "scalability not supported\n");
1832
1833             // bin shape stuff FIXME
1834         }
1835     }
1836     return 0;
1837 }
1838
1839 /**
1840  * decodes the user data stuff in the header.
1841  * Also initializes divx/xvid/lavc_version/build.
1842  */
1843 static int decode_user_data(MpegEncContext *s, GetBitContext *gb){
1844     char buf[256];
1845     int i;
1846     int e;
1847     int ver = 0, build = 0, ver2 = 0, ver3 = 0;
1848     char last;
1849
1850     for(i=0; i<255 && get_bits_count(gb) < gb->size_in_bits; i++){
1851         if(show_bits(gb, 23) == 0) break;
1852         buf[i]= get_bits(gb, 8);
1853     }
1854     buf[i]=0;
1855
1856     /* divx detection */
1857     e=sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
1858     if(e<2)
1859         e=sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
1860     if(e>=2){
1861         s->divx_version= ver;
1862         s->divx_build= build;
1863         s->divx_packed= e==3 && last=='p';
1864         if(s->divx_packed && !s->showed_packed_warning) {
1865             av_log(s->avctx, AV_LOG_WARNING, "Invalid and inefficient vfw-avi packed B frames detected\n");
1866             s->showed_packed_warning=1;
1867         }
1868     }
1869
1870     /* ffmpeg detection */
1871     e=sscanf(buf, "FFmpe%*[^b]b%d", &build)+3;
1872     if(e!=4)
1873         e=sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
1874     if(e!=4){
1875         e=sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3)+1;
1876         if (e>1)
1877             build= (ver<<16) + (ver2<<8) + ver3;
1878     }
1879     if(e!=4){
1880         if(strcmp(buf, "ffmpeg")==0){
1881             s->lavc_build= 4600;
1882         }
1883     }
1884     if(e==4){
1885         s->lavc_build= build;
1886     }
1887
1888     /* Xvid detection */
1889     e=sscanf(buf, "XviD%d", &build);
1890     if(e==1){
1891         s->xvid_build= build;
1892     }
1893
1894     return 0;
1895 }
1896
1897 static int decode_vop_header(MpegEncContext *s, GetBitContext *gb){
1898     int time_incr, time_increment;
1899
1900     s->pict_type = get_bits(gb, 2) + FF_I_TYPE;        /* pict type: I = 0 , P = 1 */
1901     if(s->pict_type==FF_B_TYPE && s->low_delay && s->vol_control_parameters==0 && !(s->flags & CODEC_FLAG_LOW_DELAY)){
1902         av_log(s->avctx, AV_LOG_ERROR, "low_delay flag incorrectly, clearing it\n");
1903         s->low_delay=0;
1904     }
1905
1906     s->partitioned_frame= s->data_partitioning && s->pict_type!=FF_B_TYPE;
1907     if(s->partitioned_frame)
1908         s->decode_mb= mpeg4_decode_partitioned_mb;
1909     else
1910         s->decode_mb= mpeg4_decode_mb;
1911
1912     time_incr=0;
1913     while (get_bits1(gb) != 0)
1914         time_incr++;
1915
1916     check_marker(gb, "before time_increment");
1917
1918     if(s->time_increment_bits==0 || !(show_bits(gb, s->time_increment_bits+1)&1)){
1919         av_log(s->avctx, AV_LOG_ERROR, "hmm, seems the headers are not complete, trying to guess time_increment_bits\n");
1920
1921         for(s->time_increment_bits=1 ;s->time_increment_bits<16; s->time_increment_bits++){
1922             if (    s->pict_type == FF_P_TYPE
1923                 || (s->pict_type == FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE)) {
1924                 if((show_bits(gb, s->time_increment_bits+6)&0x37) == 0x30) break;
1925             }else
1926                 if((show_bits(gb, s->time_increment_bits+5)&0x1F) == 0x18) break;
1927         }
1928
1929         av_log(s->avctx, AV_LOG_ERROR, "my guess is %d bits ;)\n",s->time_increment_bits);
1930     }
1931
1932     if(IS_3IV1) time_increment= get_bits1(gb); //FIXME investigate further
1933     else time_increment= get_bits(gb, s->time_increment_bits);
1934
1935     if(s->pict_type!=FF_B_TYPE){
1936         s->last_time_base= s->time_base;
1937         s->time_base+= time_incr;
1938         s->time= s->time_base*s->avctx->time_base.den + time_increment;
1939         if(s->workaround_bugs&FF_BUG_UMP4){
1940             if(s->time < s->last_non_b_time){
1941                 /* header is not mpeg-4-compatible, broken encoder,
1942                  * trying to workaround */
1943                 s->time_base++;
1944                 s->time+= s->avctx->time_base.den;
1945             }
1946         }
1947         s->pp_time= s->time - s->last_non_b_time;
1948         s->last_non_b_time= s->time;
1949     }else{
1950         s->time= (s->last_time_base + time_incr)*s->avctx->time_base.den + time_increment;
1951         s->pb_time= s->pp_time - (s->last_non_b_time - s->time);
1952         if(s->pp_time <=s->pb_time || s->pp_time <= s->pp_time - s->pb_time || s->pp_time<=0){
1953             /* messed up order, maybe after seeking? skipping current b-frame */
1954             return FRAME_SKIPPED;
1955         }
1956         ff_mpeg4_init_direct_mv(s);
1957
1958         if(s->t_frame==0) s->t_frame= s->pb_time;
1959         if(s->t_frame==0) s->t_frame=1; // 1/0 protection
1960         s->pp_field_time= (  ROUNDED_DIV(s->last_non_b_time, s->t_frame)
1961                            - ROUNDED_DIV(s->last_non_b_time - s->pp_time, s->t_frame))*2;
1962         s->pb_field_time= (  ROUNDED_DIV(s->time, s->t_frame)
1963                            - ROUNDED_DIV(s->last_non_b_time - s->pp_time, s->t_frame))*2;
1964         if(!s->progressive_sequence){
1965             if(s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1)
1966                 return FRAME_SKIPPED;
1967         }
1968     }
1969
1970     if(s->avctx->time_base.num)
1971         s->current_picture_ptr->pts= (s->time + s->avctx->time_base.num/2) / s->avctx->time_base.num;
1972     else
1973         s->current_picture_ptr->pts= AV_NOPTS_VALUE;
1974     if(s->avctx->debug&FF_DEBUG_PTS)
1975         av_log(s->avctx, AV_LOG_DEBUG, "MPEG4 PTS: %"PRId64"\n", s->current_picture_ptr->pts);
1976
1977     check_marker(gb, "before vop_coded");
1978
1979     /* vop coded */
1980     if (get_bits1(gb) != 1){
1981         if(s->avctx->debug&FF_DEBUG_PICT_INFO)
1982             av_log(s->avctx, AV_LOG_ERROR, "vop not coded\n");
1983         return FRAME_SKIPPED;
1984     }
1985     if (s->shape != BIN_ONLY_SHAPE && ( s->pict_type == FF_P_TYPE
1986                           || (s->pict_type == FF_S_TYPE && s->vol_sprite_usage==GMC_SPRITE))) {
1987         /* rounding type for motion estimation */
1988         s->no_rounding = get_bits1(gb);
1989     } else {
1990         s->no_rounding = 0;
1991     }
1992 //FIXME reduced res stuff
1993
1994      if (s->shape != RECT_SHAPE) {
1995          if (s->vol_sprite_usage != 1 || s->pict_type != FF_I_TYPE) {
1996              int width, height, hor_spat_ref, ver_spat_ref;
1997
1998              width = get_bits(gb, 13);
1999              skip_bits1(gb);   /* marker */
2000              height = get_bits(gb, 13);
2001              skip_bits1(gb);   /* marker */
2002              hor_spat_ref = get_bits(gb, 13); /* hor_spat_ref */
2003              skip_bits1(gb);   /* marker */
2004              ver_spat_ref = get_bits(gb, 13); /* ver_spat_ref */
2005          }
2006          skip_bits1(gb); /* change_CR_disable */
2007
2008          if (get_bits1(gb) != 0) {
2009              skip_bits(gb, 8); /* constant_alpha_value */
2010          }
2011      }
2012 //FIXME complexity estimation stuff
2013
2014      if (s->shape != BIN_ONLY_SHAPE) {
2015          skip_bits_long(gb, s->cplx_estimation_trash_i);
2016          if(s->pict_type != FF_I_TYPE)
2017             skip_bits_long(gb, s->cplx_estimation_trash_p);
2018          if(s->pict_type == FF_B_TYPE)
2019             skip_bits_long(gb, s->cplx_estimation_trash_b);
2020
2021          s->intra_dc_threshold= mpeg4_dc_threshold[ get_bits(gb, 3) ];
2022          if(!s->progressive_sequence){
2023              s->top_field_first= get_bits1(gb);
2024              s->alternate_scan= get_bits1(gb);
2025          }else
2026              s->alternate_scan= 0;
2027      }
2028
2029      if(s->alternate_scan){
2030          ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_alternate_vertical_scan);
2031          ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_alternate_vertical_scan);
2032          ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
2033          ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2034      } else{
2035          ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_zigzag_direct);
2036          ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_zigzag_direct);
2037          ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
2038          ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2039      }
2040
2041      if(s->pict_type == FF_S_TYPE && (s->vol_sprite_usage==STATIC_SPRITE || s->vol_sprite_usage==GMC_SPRITE)){
2042          mpeg4_decode_sprite_trajectory(s, gb);
2043          if(s->sprite_brightness_change) av_log(s->avctx, AV_LOG_ERROR, "sprite_brightness_change not supported\n");
2044          if(s->vol_sprite_usage==STATIC_SPRITE) av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
2045      }
2046
2047      if (s->shape != BIN_ONLY_SHAPE) {
2048          s->chroma_qscale= s->qscale = get_bits(gb, s->quant_precision);
2049          if(s->qscale==0){
2050              av_log(s->avctx, AV_LOG_ERROR, "Error, header damaged or not MPEG4 header (qscale=0)\n");
2051              return -1; // makes no sense to continue, as there is nothing left from the image then
2052          }
2053
2054          if (s->pict_type != FF_I_TYPE) {
2055              s->f_code = get_bits(gb, 3);       /* fcode_for */
2056              if(s->f_code==0){
2057                  av_log(s->avctx, AV_LOG_ERROR, "Error, header damaged or not MPEG4 header (f_code=0)\n");
2058                  return -1; // makes no sense to continue, as the MV decoding will break very quickly
2059              }
2060          }else
2061              s->f_code=1;
2062
2063          if (s->pict_type == FF_B_TYPE) {
2064              s->b_code = get_bits(gb, 3);
2065          }else
2066              s->b_code=1;
2067
2068          if(s->avctx->debug&FF_DEBUG_PICT_INFO){
2069              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",
2070                  s->qscale, s->f_code, s->b_code,
2071                  s->pict_type == FF_I_TYPE ? "I" : (s->pict_type == FF_P_TYPE ? "P" : (s->pict_type == FF_B_TYPE ? "B" : "S")),
2072                  gb->size_in_bits,s->progressive_sequence, s->alternate_scan, s->top_field_first,
2073                  s->quarter_sample ? "q" : "h", s->data_partitioning, s->resync_marker, s->num_sprite_warping_points,
2074                  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);
2075          }
2076
2077          if(!s->scalability){
2078              if (s->shape!=RECT_SHAPE && s->pict_type!=FF_I_TYPE) {
2079                  skip_bits1(gb); // vop shape coding type
2080              }
2081          }else{
2082              if(s->enhancement_type){
2083                  int load_backward_shape= get_bits1(gb);
2084                  if(load_backward_shape){
2085                      av_log(s->avctx, AV_LOG_ERROR, "load backward shape isn't supported\n");
2086                  }
2087              }
2088              skip_bits(gb, 2); //ref_select_code
2089          }
2090      }
2091      /* detect buggy encoders which don't set the low_delay flag (divx4/xvid/opendivx)*/
2092      // note we cannot detect divx5 without b-frames easily (although it's buggy too)
2093      if(s->vo_type==0 && s->vol_control_parameters==0 && s->divx_version==-1 && s->picture_number==0){
2094          av_log(s->avctx, AV_LOG_WARNING, "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
2095          s->low_delay=1;
2096      }
2097
2098      s->picture_number++; // better than pic number==0 always ;)
2099
2100      s->y_dc_scale_table= ff_mpeg4_y_dc_scale_table; //FIXME add short header support
2101      s->c_dc_scale_table= ff_mpeg4_c_dc_scale_table;
2102
2103      if(s->workaround_bugs&FF_BUG_EDGE){
2104          s->h_edge_pos= s->width;
2105          s->v_edge_pos= s->height;
2106      }
2107      return 0;
2108 }
2109
2110 /**
2111  * decode mpeg4 headers
2112  * @return <0 if no VOP found (or a damaged one)
2113  *         FRAME_SKIPPED if a not coded VOP is found
2114  *         0 if a VOP is found
2115  */
2116 int ff_mpeg4_decode_picture_header(MpegEncContext * s, GetBitContext *gb)
2117 {
2118     int startcode, v;
2119
2120     /* search next start code */
2121     align_get_bits(gb);
2122
2123     if(s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630){
2124         skip_bits(gb, 24);
2125         if(get_bits(gb, 8) == 0xF0)
2126             goto end;
2127     }
2128
2129     startcode = 0xff;
2130     for(;;) {
2131         if(get_bits_count(gb) >= gb->size_in_bits){
2132             if(gb->size_in_bits==8 && (s->divx_version>=0 || s->xvid_build>=0)){
2133                 av_log(s->avctx, AV_LOG_WARNING, "frame skip %d\n", gb->size_in_bits);
2134                 return FRAME_SKIPPED; //divx bug
2135             }else
2136                 return -1; //end of stream
2137         }
2138
2139         /* use the bits after the test */
2140         v = get_bits(gb, 8);
2141         startcode = ((startcode << 8) | v) & 0xffffffff;
2142
2143         if((startcode&0xFFFFFF00) != 0x100)
2144             continue; //no startcode
2145
2146         if(s->avctx->debug&FF_DEBUG_STARTCODE){
2147             av_log(s->avctx, AV_LOG_DEBUG, "startcode: %3X ", startcode);
2148             if     (startcode<=0x11F) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
2149             else if(startcode<=0x12F) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
2150             else if(startcode<=0x13F) av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2151             else if(startcode<=0x15F) av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
2152             else if(startcode<=0x1AF) av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2153             else if(startcode==0x1B0) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
2154             else if(startcode==0x1B1) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
2155             else if(startcode==0x1B2) av_log(s->avctx, AV_LOG_DEBUG, "User Data");
2156             else if(startcode==0x1B3) av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
2157             else if(startcode==0x1B4) av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
2158             else if(startcode==0x1B5) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
2159             else if(startcode==0x1B6) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
2160             else if(startcode==0x1B7) av_log(s->avctx, AV_LOG_DEBUG, "slice start");
2161             else if(startcode==0x1B8) av_log(s->avctx, AV_LOG_DEBUG, "extension start");
2162             else if(startcode==0x1B9) av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
2163             else if(startcode==0x1BA) av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
2164             else if(startcode==0x1BB) av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
2165             else if(startcode==0x1BC) av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
2166             else if(startcode==0x1BD) av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
2167             else if(startcode==0x1BE) av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
2168             else if(startcode==0x1BF) av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
2169             else if(startcode==0x1C0) av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
2170             else if(startcode==0x1C1) av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
2171             else if(startcode==0x1C2) av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
2172             else if(startcode==0x1C3) av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
2173             else if(startcode<=0x1C5) av_log(s->avctx, AV_LOG_DEBUG, "reserved");
2174             else if(startcode<=0x1FF) av_log(s->avctx, AV_LOG_DEBUG, "System start");
2175             av_log(s->avctx, AV_LOG_DEBUG, " at %d\n", get_bits_count(gb));
2176         }
2177
2178         if(startcode >= 0x120 && startcode <= 0x12F){
2179             if(decode_vol_header(s, gb) < 0)
2180                 return -1;
2181         }
2182         else if(startcode == USER_DATA_STARTCODE){
2183             decode_user_data(s, gb);
2184         }
2185         else if(startcode == GOP_STARTCODE){
2186             mpeg4_decode_gop_header(s, gb);
2187         }
2188         else if(startcode == VOP_STARTCODE){
2189             break;
2190         }
2191
2192         align_get_bits(gb);
2193         startcode = 0xff;
2194     }
2195 end:
2196     if(s->flags& CODEC_FLAG_LOW_DELAY)
2197         s->low_delay=1;
2198     s->avctx->has_b_frames= !s->low_delay;
2199     return decode_vop_header(s, gb);
2200 }
2201
2202 static av_cold int decode_init(AVCodecContext *avctx)
2203 {
2204     MpegEncContext *s = avctx->priv_data;
2205     int ret;
2206     static int done = 0;
2207
2208     s->divx_version=
2209     s->divx_build=
2210     s->xvid_build=
2211     s->lavc_build= -1;
2212
2213     if((ret=ff_h263_decode_init(avctx)) < 0)
2214         return ret;
2215
2216     if (!done) {
2217         done = 1;
2218
2219         init_rl(&ff_mpeg4_rl_intra, ff_mpeg4_static_rl_table_store[0]);
2220         init_rl(&rvlc_rl_inter, ff_mpeg4_static_rl_table_store[1]);
2221         init_rl(&rvlc_rl_intra, ff_mpeg4_static_rl_table_store[2]);
2222         INIT_VLC_RL(ff_mpeg4_rl_intra, 554);
2223         INIT_VLC_RL(rvlc_rl_inter, 1072);
2224         INIT_VLC_RL(rvlc_rl_intra, 1072);
2225         INIT_VLC_STATIC(&dc_lum, DC_VLC_BITS, 10 /* 13 */,
2226                  &ff_mpeg4_DCtab_lum[0][1], 2, 1,
2227                  &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
2228         INIT_VLC_STATIC(&dc_chrom, DC_VLC_BITS, 10 /* 13 */,
2229                  &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
2230                  &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
2231         INIT_VLC_STATIC(&sprite_trajectory, SPRITE_TRAJ_VLC_BITS, 15,
2232                  &sprite_trajectory_tab[0][1], 4, 2,
2233                  &sprite_trajectory_tab[0][0], 4, 2, 128);
2234         INIT_VLC_STATIC(&mb_type_b_vlc, MB_TYPE_B_VLC_BITS, 4,
2235                  &mb_type_b_tab[0][1], 2, 1,
2236                  &mb_type_b_tab[0][0], 2, 1, 16);
2237     }
2238
2239     s->h263_pred = 1;
2240     s->low_delay = 0; //default, might be overriden in the vol header during header parsing
2241     s->decode_mb= mpeg4_decode_mb;
2242     s->time_increment_bits = 4; /* default value for broken headers */
2243     avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
2244
2245     return 0;
2246 }
2247
2248 AVCodec ff_mpeg4_decoder = {
2249     "mpeg4",
2250     AVMEDIA_TYPE_VIDEO,
2251     CODEC_ID_MPEG4,
2252     sizeof(MpegEncContext),
2253     decode_init,
2254     NULL,
2255     ff_h263_decode_end,
2256     ff_h263_decode_frame,
2257     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY | CODEC_CAP_FRAME_THREADS,
2258     .flush= ff_mpeg_flush,
2259     .max_lowres= 3,
2260     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
2261     .pix_fmts= ff_hwaccel_pixfmt_list_420,
2262     .update_thread_context= ONLY_IF_THREADS_ENABLED(ff_mpeg_update_thread_context)
2263 };
2264
2265
2266 #if CONFIG_MPEG4_VDPAU_DECODER
2267 AVCodec ff_mpeg4_vdpau_decoder = {
2268     "mpeg4_vdpau",
2269     AVMEDIA_TYPE_VIDEO,
2270     CODEC_ID_MPEG4,
2271     sizeof(MpegEncContext),
2272     decode_init,
2273     NULL,
2274     ff_h263_decode_end,
2275     ff_h263_decode_frame,
2276     CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY | CODEC_CAP_HWACCEL_VDPAU,
2277     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),
2278     .pix_fmts= (const enum PixelFormat[]){PIX_FMT_VDPAU_MPEG4, PIX_FMT_NONE},
2279 };
2280 #endif