git.sesse.net Git - ffmpeg/blob - libavcodec/mpeg4videodec.c

   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 #define UNCHECKED_BITSTREAM_READER 1
  24
  25 #include "libavutil/opt.h"
  26 #include "error_resilience.h"
  27 #include "idctdsp.h"
  28 #include "internal.h"
  29 #include "mpegutils.h"
  30 #include "mpegvideo.h"
  31 #include "mpeg4video.h"
  32 #include "h263.h"
  33 #include "thread.h"
  34 #include "xvididct.h"
  35
  36 /* The defines below define the number of bits that are read at once for
  37  * reading vlc values. Changing these may improve speed and data cache needs
  38  * be aware though that decreasing them may need the number of stages that is
  39  * passed to get_vlc* to be increased. */
  40 #define SPRITE_TRAJ_VLC_BITS 6
  41 #define DC_VLC_BITS 9
  42 #define MB_TYPE_B_VLC_BITS 4
  43
  44 static VLC dc_lum, dc_chrom;
  45 static VLC sprite_trajectory;
  46 static VLC mb_type_b_vlc;
  47
  48 static const int mb_type_b_map[4] = {
  49     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
  50     MB_TYPE_L0L1    | MB_TYPE_16x16,
  51     MB_TYPE_L1      | MB_TYPE_16x16,
  52     MB_TYPE_L0      | MB_TYPE_16x16,
  53 };
  54
  55 /**
  56  * Predict the ac.
  57  * @param n block index (0-3 are luma, 4-5 are chroma)
  58  * @param dir the ac prediction direction
  59  */
  60 void ff_mpeg4_pred_ac(MpegEncContext *s, int16_t *block, int n, int dir)
  61 {
  62     int i;
  63     int16_t *ac_val, *ac_val1;
  64     int8_t *const qscale_table = s->current_picture.qscale_table;
  65
  66     /* find prediction */
  67     ac_val  = s->ac_val[0][0] + s->block_index[n] * 16;
  68     ac_val1 = ac_val;
  69     if (s->ac_pred) {
  70         if (dir == 0) {
  71             const int xy = s->mb_x - 1 + s->mb_y * s->mb_stride;
  72             /* left prediction */
  73             ac_val -= 16;
  74
  75             if (s->mb_x == 0 || s->qscale == qscale_table[xy] ||
  76                 n == 1 || n == 3) {
  77                 /* same qscale */
  78                 for (i = 1; i < 8; i++)
  79                     block[s->idsp.idct_permutation[i << 3]] += ac_val[i];
  80             } else {
  81                 /* different qscale, we must rescale */
  82                 for (i = 1; i < 8; i++)
  83                     block[s->idsp.idct_permutation[i << 3]] += ROUNDED_DIV(ac_val[i] * qscale_table[xy], s->qscale);
  84             }
  85         } else {
  86             const int xy = s->mb_x + s->mb_y * s->mb_stride - s->mb_stride;
  87             /* top prediction */
  88             ac_val -= 16 * s->block_wrap[n];
  89
  90             if (s->mb_y == 0 || s->qscale == qscale_table[xy] ||
  91                 n == 2 || n == 3) {
  92                 /* same qscale */
  93                 for (i = 1; i < 8; i++)
  94                     block[s->idsp.idct_permutation[i]] += ac_val[i + 8];
  95             } else {
  96                 /* different qscale, we must rescale */
  97                 for (i = 1; i < 8; i++)
  98                     block[s->idsp.idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8] * qscale_table[xy], s->qscale);
  99             }
 100         }
 101     }
 102     /* left copy */
 103     for (i = 1; i < 8; i++)
 104         ac_val1[i] = block[s->idsp.idct_permutation[i << 3]];
 105
 106     /* top copy */
 107     for (i = 1; i < 8; i++)
 108         ac_val1[8 + i] = block[s->idsp.idct_permutation[i]];
 109 }
 110
 111 /**
 112  * check if the next stuff is a resync marker or the end.
 113  * @return 0 if not
 114  */
 115 static inline int mpeg4_is_resync(Mpeg4DecContext *ctx)
 116 {
 117     MpegEncContext *s = &ctx->m;
 118     int bits_count = get_bits_count(&s->gb);
 119     int v          = show_bits(&s->gb, 16);
 120
 121     if (s->workaround_bugs & FF_BUG_NO_PADDING && !ctx->resync_marker)
 122         return 0;
 123
 124     while (v <= 0xFF) {
 125         if (s->pict_type == AV_PICTURE_TYPE_B ||
 126             (v >> (8 - s->pict_type) != 1) || s->partitioned_frame)
 127             break;
 128         skip_bits(&s->gb, 8 + s->pict_type);
 129         bits_count += 8 + s->pict_type;
 130         v = show_bits(&s->gb, 16);
 131     }
 132
 133     if (bits_count + 8 >= s->gb.size_in_bits) {
 134         v >>= 8;
 135         v  |= 0x7F >> (7 - (bits_count & 7));
 136
 137         if (v == 0x7F)
 138             return s->mb_num;
 139     } else {
 140         if (v == ff_mpeg4_resync_prefix[bits_count & 7]) {
 141             int len, mb_num;
 142             int mb_num_bits = av_log2(s->mb_num - 1) + 1;
 143             GetBitContext gb = s->gb;
 144
 145             skip_bits(&s->gb, 1);
 146             align_get_bits(&s->gb);
 147
 148             for (len = 0; len < 32; len++)
 149                 if (get_bits1(&s->gb))
 150                     break;
 151
 152             mb_num = get_bits(&s->gb, mb_num_bits);
 153             if (!mb_num || mb_num > s->mb_num || get_bits_count(&s->gb)+6 > s->gb.size_in_bits)
 154                 mb_num= -1;
 155
 156             s->gb = gb;
 157
 158             if (len >= ff_mpeg4_get_video_packet_prefix_length(s))
 159                 return mb_num;
 160         }
 161     }
 162     return 0;
 163 }
 164
 165 static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *gb)
 166 {
 167     MpegEncContext *s = &ctx->m;
 168     int a     = 2 << s->sprite_warping_accuracy;
 169     int rho   = 3  - s->sprite_warping_accuracy;
 170     int r     = 16 / a;
 171     int alpha = 0;
 172     int beta  = 0;
 173     int w     = s->width;
 174     int h     = s->height;
 175     int min_ab, i, w2, h2, w3, h3;
 176     int sprite_ref[4][2];
 177     int virtual_ref[2][2];
 178
 179     // only true for rectangle shapes
 180     const int vop_ref[4][2] = { { 0, 0 },         { s->width, 0 },
 181                                 { 0, s->height }, { s->width, s->height } };
 182     int d[4][2]             = { { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } };
 183
 184     if (w <= 0 || h <= 0)
 185         return AVERROR_INVALIDDATA;
 186
 187     for (i = 0; i < ctx->num_sprite_warping_points; i++) {
 188         int length;
 189         int x = 0, y = 0;
 190
 191         length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 192         if (length > 0)
 193             x = get_xbits(gb, length);
 194
 195         if (!(ctx->divx_version == 500 && ctx->divx_build == 413))
 196             check_marker(gb, "before sprite_trajectory");
 197
 198         length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 199         if (length > 0)
 200             y = get_xbits(gb, length);
 201
 202         check_marker(gb, "after sprite_trajectory");
 203         ctx->sprite_traj[i][0] = d[i][0] = x;
 204         ctx->sprite_traj[i][1] = d[i][1] = y;
 205     }
 206     for (; i < 4; i++)
 207         ctx->sprite_traj[i][0] = ctx->sprite_traj[i][1] = 0;
 208
 209     while ((1 << alpha) < w)
 210         alpha++;
 211     while ((1 << beta) < h)
 212         beta++;  /* typo in the mpeg4 std for the definition of w' and h' */
 213     w2 = 1 << alpha;
 214     h2 = 1 << beta;
 215
 216     // Note, the 4th point isn't used for GMC
 217     if (ctx->divx_version == 500 && ctx->divx_build == 413) {
 218         sprite_ref[0][0] = a * vop_ref[0][0] + d[0][0];
 219         sprite_ref[0][1] = a * vop_ref[0][1] + d[0][1];
 220         sprite_ref[1][0] = a * vop_ref[1][0] + d[0][0] + d[1][0];
 221         sprite_ref[1][1] = a * vop_ref[1][1] + d[0][1] + d[1][1];
 222         sprite_ref[2][0] = a * vop_ref[2][0] + d[0][0] + d[2][0];
 223         sprite_ref[2][1] = a * vop_ref[2][1] + d[0][1] + d[2][1];
 224     } else {
 225         sprite_ref[0][0] = (a >> 1) * (2 * vop_ref[0][0] + d[0][0]);
 226         sprite_ref[0][1] = (a >> 1) * (2 * vop_ref[0][1] + d[0][1]);
 227         sprite_ref[1][0] = (a >> 1) * (2 * vop_ref[1][0] + d[0][0] + d[1][0]);
 228         sprite_ref[1][1] = (a >> 1) * (2 * vop_ref[1][1] + d[0][1] + d[1][1]);
 229         sprite_ref[2][0] = (a >> 1) * (2 * vop_ref[2][0] + d[0][0] + d[2][0]);
 230         sprite_ref[2][1] = (a >> 1) * (2 * vop_ref[2][1] + d[0][1] + d[2][1]);
 231     }
 232     /* sprite_ref[3][0] = (a >> 1) * (2 * vop_ref[3][0] + d[0][0] + d[1][0] + d[2][0] + d[3][0]);
 233      * sprite_ref[3][1] = (a >> 1) * (2 * vop_ref[3][1] + d[0][1] + d[1][1] + d[2][1] + d[3][1]); */
 234
 235     /* this is mostly identical to the mpeg4 std (and is totally unreadable
 236      * because of that...). Perhaps it should be reordered to be more readable.
 237      * The idea behind this virtual_ref mess is to be able to use shifts later
 238      * per pixel instead of divides so the distance between points is converted
 239      * from w&h based to w2&h2 based which are of the 2^x form. */
 240     virtual_ref[0][0] = 16 * (vop_ref[0][0] + w2) +
 241                          ROUNDED_DIV(((w - w2) *
 242                                       (r * sprite_ref[0][0] - 16 * vop_ref[0][0]) +
 243                                       w2 * (r * sprite_ref[1][0] - 16 * vop_ref[1][0])), w);
 244     virtual_ref[0][1] = 16 * vop_ref[0][1] +
 245                         ROUNDED_DIV(((w - w2) *
 246                                      (r * sprite_ref[0][1] - 16 * vop_ref[0][1]) +
 247                                      w2 * (r * sprite_ref[1][1] - 16 * vop_ref[1][1])), w);
 248     virtual_ref[1][0] = 16 * vop_ref[0][0] +
 249                         ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][0] - 16 * vop_ref[0][0]) +
 250                                      h2 * (r * sprite_ref[2][0] - 16 * vop_ref[2][0])), h);
 251     virtual_ref[1][1] = 16 * (vop_ref[0][1] + h2) +
 252                         ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][1] - 16 * vop_ref[0][1]) +
 253                                      h2 * (r * sprite_ref[2][1] - 16 * vop_ref[2][1])), h);
 254
 255     switch (ctx->num_sprite_warping_points) {
 256     case 0:
 257         s->sprite_offset[0][0] =
 258         s->sprite_offset[0][1] =
 259         s->sprite_offset[1][0] =
 260         s->sprite_offset[1][1] = 0;
 261         s->sprite_delta[0][0]  = a;
 262         s->sprite_delta[0][1]  =
 263         s->sprite_delta[1][0]  = 0;
 264         s->sprite_delta[1][1]  = a;
 265         ctx->sprite_shift[0]   =
 266         ctx->sprite_shift[1]   = 0;
 267         break;
 268     case 1:     // GMC only
 269         s->sprite_offset[0][0] = sprite_ref[0][0] - a * vop_ref[0][0];
 270         s->sprite_offset[0][1] = sprite_ref[0][1] - a * vop_ref[0][1];
 271         s->sprite_offset[1][0] = ((sprite_ref[0][0] >> 1) | (sprite_ref[0][0] & 1)) -
 272                                  a * (vop_ref[0][0] / 2);
 273         s->sprite_offset[1][1] = ((sprite_ref[0][1] >> 1) | (sprite_ref[0][1] & 1)) -
 274                                  a * (vop_ref[0][1] / 2);
 275         s->sprite_delta[0][0]  = a;
 276         s->sprite_delta[0][1]  =
 277         s->sprite_delta[1][0]  = 0;
 278         s->sprite_delta[1][1]  = a;
 279         ctx->sprite_shift[0]   =
 280         ctx->sprite_shift[1]   = 0;
 281         break;
 282     case 2:
 283         s->sprite_offset[0][0] = (sprite_ref[0][0] << (alpha + rho)) +
 284                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 285                                  (-vop_ref[0][0]) +
 286                                  (r * sprite_ref[0][1] - virtual_ref[0][1]) *
 287                                  (-vop_ref[0][1]) + (1 << (alpha + rho - 1));
 288         s->sprite_offset[0][1] = (sprite_ref[0][1] << (alpha + rho)) +
 289                                  (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 290                                  (-vop_ref[0][0]) +
 291                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 292                                  (-vop_ref[0][1]) + (1 << (alpha + rho - 1));
 293         s->sprite_offset[1][0] = ((-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 294                                   (-2 * vop_ref[0][0] + 1) +
 295                                   (r * sprite_ref[0][1] - virtual_ref[0][1]) *
 296                                   (-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
 297                                   sprite_ref[0][0] - 16 * w2 + (1 << (alpha + rho + 1)));
 298         s->sprite_offset[1][1] = ((-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 299                                   (-2 * vop_ref[0][0] + 1) +
 300                                   (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 301                                   (-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
 302                                   sprite_ref[0][1] - 16 * w2 + (1 << (alpha + rho + 1)));
 303         s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
 304         s->sprite_delta[0][1] = (+r * sprite_ref[0][1] - virtual_ref[0][1]);
 305         s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]);
 306         s->sprite_delta[1][1] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
 307
 308         ctx->sprite_shift[0]  = alpha + rho;
 309         ctx->sprite_shift[1]  = alpha + rho + 2;
 310         break;
 311     case 3:
 312         min_ab = FFMIN(alpha, beta);
 313         w3     = w2 >> min_ab;
 314         h3     = h2 >> min_ab;
 315         s->sprite_offset[0][0] = (sprite_ref[0][0] << (alpha + beta + rho - min_ab)) +
 316                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 317                                  h3 * (-vop_ref[0][0]) +
 318                                  (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
 319                                  w3 * (-vop_ref[0][1]) +
 320                                  (1 << (alpha + beta + rho - min_ab - 1));
 321         s->sprite_offset[0][1] = (sprite_ref[0][1] << (alpha + beta + rho - min_ab)) +
 322                                  (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 323                                  h3 * (-vop_ref[0][0]) +
 324                                  (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
 325                                  w3 * (-vop_ref[0][1]) +
 326                                  (1 << (alpha + beta + rho - min_ab - 1));
 327         s->sprite_offset[1][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 328                                  h3 * (-2 * vop_ref[0][0] + 1) +
 329                                  (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
 330                                  w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
 331                                  r * sprite_ref[0][0] - 16 * w2 * h3 +
 332                                  (1 << (alpha + beta + rho - min_ab + 1));
 333         s->sprite_offset[1][1] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 334                                  h3 * (-2 * vop_ref[0][0] + 1) +
 335                                  (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
 336                                  w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
 337                                  r * sprite_ref[0][1] - 16 * w2 * h3 +
 338                                  (1 << (alpha + beta + rho - min_ab + 1));
 339         s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3;
 340         s->sprite_delta[0][1] = (-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3;
 341         s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3;
 342         s->sprite_delta[1][1] = (-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3;
 343
 344         ctx->sprite_shift[0]  = alpha + beta + rho - min_ab;
 345         ctx->sprite_shift[1]  = alpha + beta + rho - min_ab + 2;
 346         break;
 347     }
 348     /* try to simplify the situation */
 349     if (s->sprite_delta[0][0] == a << ctx->sprite_shift[0] &&
 350         s->sprite_delta[0][1] == 0 &&
 351         s->sprite_delta[1][0] == 0 &&
 352         s->sprite_delta[1][1] == a << ctx->sprite_shift[0]) {
 353         s->sprite_offset[0][0] >>= ctx->sprite_shift[0];
 354         s->sprite_offset[0][1] >>= ctx->sprite_shift[0];
 355         s->sprite_offset[1][0] >>= ctx->sprite_shift[1];
 356         s->sprite_offset[1][1] >>= ctx->sprite_shift[1];
 357         s->sprite_delta[0][0] = a;
 358         s->sprite_delta[0][1] = 0;
 359         s->sprite_delta[1][0] = 0;
 360         s->sprite_delta[1][1] = a;
 361         ctx->sprite_shift[0] = 0;
 362         ctx->sprite_shift[1] = 0;
 363         s->real_sprite_warping_points = 1;
 364     } else {
 365         int shift_y = 16 - ctx->sprite_shift[0];
 366         int shift_c = 16 - ctx->sprite_shift[1];
 367         for (i = 0; i < 2; i++) {
 368             s->sprite_offset[0][i] <<= shift_y;
 369             s->sprite_offset[1][i] <<= shift_c;
 370             s->sprite_delta[0][i]  <<= shift_y;
 371             s->sprite_delta[1][i]  <<= shift_y;
 372             ctx->sprite_shift[i]     = 16;
 373         }
 374         s->real_sprite_warping_points = ctx->num_sprite_warping_points;
 375     }
 376
 377     return 0;
 378 }
 379
 380 static int decode_new_pred(Mpeg4DecContext *ctx, GetBitContext *gb) {
 381     int len = FFMIN(ctx->time_increment_bits + 3, 15);
 382
 383     get_bits(gb, len);
 384     if (get_bits1(gb))
 385         get_bits(gb, len);
 386     check_marker(gb, "after new_pred");
 387
 388     return 0;
 389 }
 390
 391 /**
 392  * Decode the next video packet.
 393  * @return <0 if something went wrong
 394  */
 395 int ff_mpeg4_decode_video_packet_header(Mpeg4DecContext *ctx)
 396 {
 397     MpegEncContext *s = &ctx->m;
 398
 399     int mb_num_bits      = av_log2(s->mb_num - 1) + 1;
 400     int header_extension = 0, mb_num, len;
 401
 402     /* is there enough space left for a video packet + header */
 403     if (get_bits_count(&s->gb) > s->gb.size_in_bits - 20)
 404         return -1;
 405
 406     for (len = 0; len < 32; len++)
 407         if (get_bits1(&s->gb))
 408             break;
 409
 410     if (len != ff_mpeg4_get_video_packet_prefix_length(s)) {
 411         av_log(s->avctx, AV_LOG_ERROR, "marker does not match f_code\n");
 412         return -1;
 413     }
 414
 415     if (ctx->shape != RECT_SHAPE) {
 416         header_extension = get_bits1(&s->gb);
 417         // FIXME more stuff here
 418     }
 419
 420     mb_num = get_bits(&s->gb, mb_num_bits);
 421     if (mb_num >= s->mb_num) {
 422         av_log(s->avctx, AV_LOG_ERROR,
 423                "illegal mb_num in video packet (%d %d) \n", mb_num, s->mb_num);
 424         return -1;
 425     }
 426
 427     s->mb_x = mb_num % s->mb_width;
 428     s->mb_y = mb_num / s->mb_width;
 429
 430     if (ctx->shape != BIN_ONLY_SHAPE) {
 431         int qscale = get_bits(&s->gb, s->quant_precision);
 432         if (qscale)
 433             s->chroma_qscale = s->qscale = qscale;
 434     }
 435
 436     if (ctx->shape == RECT_SHAPE)
 437         header_extension = get_bits1(&s->gb);
 438
 439     if (header_extension) {
 440         int time_incr = 0;
 441
 442         while (get_bits1(&s->gb) != 0)
 443             time_incr++;
 444
 445         check_marker(&s->gb, "before time_increment in video packed header");
 446         skip_bits(&s->gb, ctx->time_increment_bits);      /* time_increment */
 447         check_marker(&s->gb, "before vop_coding_type in video packed header");
 448
 449         skip_bits(&s->gb, 2); /* vop coding type */
 450         // FIXME not rect stuff here
 451
 452         if (ctx->shape != BIN_ONLY_SHAPE) {
 453             skip_bits(&s->gb, 3); /* intra dc vlc threshold */
 454             // FIXME don't just ignore everything
 455             if (s->pict_type == AV_PICTURE_TYPE_S &&
 456                 ctx->vol_sprite_usage == GMC_SPRITE) {
 457                 if (mpeg4_decode_sprite_trajectory(ctx, &s->gb) < 0)
 458                     return AVERROR_INVALIDDATA;
 459                 av_log(s->avctx, AV_LOG_ERROR, "untested\n");
 460             }
 461
 462             // FIXME reduced res stuff here
 463
 464             if (s->pict_type != AV_PICTURE_TYPE_I) {
 465                 int f_code = get_bits(&s->gb, 3);       /* fcode_for */
 466                 if (f_code == 0)
 467                     av_log(s->avctx, AV_LOG_ERROR,
 468                            "Error, video packet header damaged (f_code=0)\n");
 469             }
 470             if (s->pict_type == AV_PICTURE_TYPE_B) {
 471                 int b_code = get_bits(&s->gb, 3);
 472                 if (b_code == 0)
 473                     av_log(s->avctx, AV_LOG_ERROR,
 474                            "Error, video packet header damaged (b_code=0)\n");
 475             }
 476         }
 477     }
 478     if (ctx->new_pred)
 479         decode_new_pred(ctx, &s->gb);
 480
 481     return 0;
 482 }
 483
 484 /**
 485  * Get the average motion vector for a GMC MB.
 486  * @param n either 0 for the x component or 1 for y
 487  * @return the average MV for a GMC MB
 488  */
 489 static inline int get_amv(Mpeg4DecContext *ctx, int n)
 490 {
 491     MpegEncContext *s = &ctx->m;
 492     int x, y, mb_v, sum, dx, dy, shift;
 493     int len     = 1 << (s->f_code + 4);
 494     const int a = s->sprite_warping_accuracy;
 495
 496     if (s->workaround_bugs & FF_BUG_AMV)
 497         len >>= s->quarter_sample;
 498
 499     if (s->real_sprite_warping_points == 1) {
 500         if (ctx->divx_version == 500 && ctx->divx_build == 413)
 501             sum = s->sprite_offset[0][n] / (1 << (a - s->quarter_sample));
 502         else
 503             sum = RSHIFT(s->sprite_offset[0][n] << s->quarter_sample, a);
 504     } else {
 505         dx    = s->sprite_delta[n][0];
 506         dy    = s->sprite_delta[n][1];
 507         shift = ctx->sprite_shift[0];
 508         if (n)
 509             dy -= 1 << (shift + a + 1);
 510         else
 511             dx -= 1 << (shift + a + 1);
 512         mb_v = s->sprite_offset[0][n] + dx * s->mb_x * 16 + dy * s->mb_y * 16;
 513
 514         sum = 0;
 515         for (y = 0; y < 16; y++) {
 516             int v;
 517
 518             v = mb_v + dy * y;
 519             // FIXME optimize
 520             for (x = 0; x < 16; x++) {
 521                 sum += v >> shift;
 522                 v   += dx;
 523             }
 524         }
 525         sum = RSHIFT(sum, a + 8 - s->quarter_sample);
 526     }
 527
 528     if (sum < -len)
 529         sum = -len;
 530     else if (sum >= len)
 531         sum = len - 1;
 532
 533     return sum;
 534 }
 535
 536 /**
 537  * Decode the dc value.
 538  * @param n block index (0-3 are luma, 4-5 are chroma)
 539  * @param dir_ptr the prediction direction will be stored here
 540  * @return the quantized dc
 541  */
 542 static inline int mpeg4_decode_dc(MpegEncContext *s, int n, int *dir_ptr)
 543 {
 544     int level, code;
 545
 546     if (n < 4)
 547         code = get_vlc2(&s->gb, dc_lum.table, DC_VLC_BITS, 1);
 548     else
 549         code = get_vlc2(&s->gb, dc_chrom.table, DC_VLC_BITS, 1);
 550
 551     if (code < 0 || code > 9 /* && s->nbit < 9 */) {
 552         av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
 553         return -1;
 554     }
 555
 556     if (code == 0) {
 557         level = 0;
 558     } else {
 559         if (IS_3IV1) {
 560             if (code == 1)
 561                 level = 2 * get_bits1(&s->gb) - 1;
 562             else {
 563                 if (get_bits1(&s->gb))
 564                     level = get_bits(&s->gb, code - 1) + (1 << (code - 1));
 565                 else
 566                     level = -get_bits(&s->gb, code - 1) - (1 << (code - 1));
 567             }
 568         } else {
 569             level = get_xbits(&s->gb, code);
 570         }
 571
 572         if (code > 8) {
 573             if (get_bits1(&s->gb) == 0) { /* marker */
 574                 if (s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT)) {
 575                     av_log(s->avctx, AV_LOG_ERROR, "dc marker bit missing\n");
 576                     return -1;
 577                 }
 578             }
 579         }
 580     }
 581
 582     return ff_mpeg4_pred_dc(s, n, level, dir_ptr, 0);
 583 }
 584
 585 /**
 586  * Decode first partition.
 587  * @return number of MBs decoded or <0 if an error occurred
 588  */
 589 static int mpeg4_decode_partition_a(Mpeg4DecContext *ctx)
 590 {
 591     MpegEncContext *s = &ctx->m;
 592     int mb_num = 0;
 593     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 594
 595     /* decode first partition */
 596     s->first_slice_line = 1;
 597     for (; s->mb_y < s->mb_height; s->mb_y++) {
 598         ff_init_block_index(s);
 599         for (; s->mb_x < s->mb_width; s->mb_x++) {
 600             const int xy = s->mb_x + s->mb_y * s->mb_stride;
 601             int cbpc;
 602             int dir = 0;
 603
 604             mb_num++;
 605             ff_update_block_index(s);
 606             if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
 607                 s->first_slice_line = 0;
 608
 609             if (s->pict_type == AV_PICTURE_TYPE_I) {
 610                 int i;
 611
 612                 do {
 613                     if (show_bits_long(&s->gb, 19) == DC_MARKER)
 614                         return mb_num - 1;
 615
 616                     cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 617                     if (cbpc < 0) {
 618                         av_log(s->avctx, AV_LOG_ERROR,
 619                                "mcbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 620                         return -1;
 621                     }
 622                 } while (cbpc == 8);
 623
 624                 s->cbp_table[xy]               = cbpc & 3;
 625                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 626                 s->mb_intra                    = 1;
 627
 628                 if (cbpc & 4)
 629                     ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 630
 631                 s->current_picture.qscale_table[xy] = s->qscale;
 632
 633                 s->mbintra_table[xy] = 1;
 634                 for (i = 0; i < 6; i++) {
 635                     int dc_pred_dir;
 636                     int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
 637                     if (dc < 0) {
 638                         av_log(s->avctx, AV_LOG_ERROR,
 639                                "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 640                         return -1;
 641                     }
 642                     dir <<= 1;
 643                     if (dc_pred_dir)
 644                         dir |= 1;
 645                 }
 646                 s->pred_dir_table[xy] = dir;
 647             } else { /* P/S_TYPE */
 648                 int mx, my, pred_x, pred_y, bits;
 649                 int16_t *const mot_val = s->current_picture.motion_val[0][s->block_index[0]];
 650                 const int stride       = s->b8_stride * 2;
 651
 652 try_again:
 653                 bits = show_bits(&s->gb, 17);
 654                 if (bits == MOTION_MARKER)
 655                     return mb_num - 1;
 656
 657                 skip_bits1(&s->gb);
 658                 if (bits & 0x10000) {
 659                     /* skip mb */
 660                     if (s->pict_type == AV_PICTURE_TYPE_S &&
 661                         ctx->vol_sprite_usage == GMC_SPRITE) {
 662                         s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
 663                                                          MB_TYPE_16x16 |
 664                                                          MB_TYPE_GMC   |
 665                                                          MB_TYPE_L0;
 666                         mx = get_amv(ctx, 0);
 667                         my = get_amv(ctx, 1);
 668                     } else {
 669                         s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
 670                                                          MB_TYPE_16x16 |
 671                                                          MB_TYPE_L0;
 672                         mx = my = 0;
 673                     }
 674                     mot_val[0]          =
 675                     mot_val[2]          =
 676                     mot_val[0 + stride] =
 677                     mot_val[2 + stride] = mx;
 678                     mot_val[1]          =
 679                     mot_val[3]          =
 680                     mot_val[1 + stride] =
 681                     mot_val[3 + stride] = my;
 682
 683                     if (s->mbintra_table[xy])
 684                         ff_clean_intra_table_entries(s);
 685                     continue;
 686                 }
 687
 688                 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 689                 if (cbpc < 0) {
 690                     av_log(s->avctx, AV_LOG_ERROR,
 691                            "mcbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 692                     return -1;
 693                 }
 694                 if (cbpc == 20)
 695                     goto try_again;
 696
 697                 s->cbp_table[xy] = cbpc & (8 + 3);  // 8 is dquant
 698
 699                 s->mb_intra = ((cbpc & 4) != 0);
 700
 701                 if (s->mb_intra) {
 702                     s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 703                     s->mbintra_table[xy] = 1;
 704                     mot_val[0]          =
 705                     mot_val[2]          =
 706                     mot_val[0 + stride] =
 707                     mot_val[2 + stride] = 0;
 708                     mot_val[1]          =
 709                     mot_val[3]          =
 710                     mot_val[1 + stride] =
 711                     mot_val[3 + stride] = 0;
 712                 } else {
 713                     if (s->mbintra_table[xy])
 714                         ff_clean_intra_table_entries(s);
 715
 716                     if (s->pict_type == AV_PICTURE_TYPE_S &&
 717                         ctx->vol_sprite_usage == GMC_SPRITE &&
 718                         (cbpc & 16) == 0)
 719                         s->mcsel = get_bits1(&s->gb);
 720                     else
 721                         s->mcsel = 0;
 722
 723                     if ((cbpc & 16) == 0) {
 724                         /* 16x16 motion prediction */
 725
 726                         ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 727                         if (!s->mcsel) {
 728                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
 729                             if (mx >= 0xffff)
 730                                 return -1;
 731
 732                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
 733                             if (my >= 0xffff)
 734                                 return -1;
 735                             s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
 736                                                              MB_TYPE_L0;
 737                         } else {
 738                             mx = get_amv(ctx, 0);
 739                             my = get_amv(ctx, 1);
 740                             s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
 741                                                              MB_TYPE_GMC   |
 742                                                              MB_TYPE_L0;
 743                         }
 744
 745                         mot_val[0]          =
 746                         mot_val[2]          =
 747                         mot_val[0 + stride] =
 748                         mot_val[2 + stride] = mx;
 749                         mot_val[1]          =
 750                         mot_val[3]          =
 751                         mot_val[1 + stride] =
 752                         mot_val[3 + stride] = my;
 753                     } else {
 754                         int i;
 755                         s->current_picture.mb_type[xy] = MB_TYPE_8x8 |
 756                                                          MB_TYPE_L0;
 757                         for (i = 0; i < 4; i++) {
 758                             int16_t *mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 759                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
 760                             if (mx >= 0xffff)
 761                                 return -1;
 762
 763                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
 764                             if (my >= 0xffff)
 765                                 return -1;
 766                             mot_val[0] = mx;
 767                             mot_val[1] = my;
 768                         }
 769                     }
 770                 }
 771             }
 772         }
 773         s->mb_x = 0;
 774     }
 775
 776     return mb_num;
 777 }
 778
 779 /**
 780  * decode second partition.
 781  * @return <0 if an error occurred
 782  */
 783 static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count)
 784 {
 785     int mb_num = 0;
 786     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 787
 788     s->mb_x = s->resync_mb_x;
 789     s->first_slice_line = 1;
 790     for (s->mb_y = s->resync_mb_y; mb_num < mb_count; s->mb_y++) {
 791         ff_init_block_index(s);
 792         for (; mb_num < mb_count && s->mb_x < s->mb_width; s->mb_x++) {
 793             const int xy = s->mb_x + s->mb_y * s->mb_stride;
 794
 795             mb_num++;
 796             ff_update_block_index(s);
 797             if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
 798                 s->first_slice_line = 0;
 799
 800             if (s->pict_type == AV_PICTURE_TYPE_I) {
 801                 int ac_pred = get_bits1(&s->gb);
 802                 int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 803                 if (cbpy < 0) {
 804                     av_log(s->avctx, AV_LOG_ERROR,
 805                            "cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 806                     return -1;
 807                 }
 808
 809                 s->cbp_table[xy]               |= cbpy << 2;
 810                 s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
 811             } else { /* P || S_TYPE */
 812                 if (IS_INTRA(s->current_picture.mb_type[xy])) {
 813                     int i;
 814                     int dir     = 0;
 815                     int ac_pred = get_bits1(&s->gb);
 816                     int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 817
 818                     if (cbpy < 0) {
 819                         av_log(s->avctx, AV_LOG_ERROR,
 820                                "I cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 821                         return -1;
 822                     }
 823
 824                     if (s->cbp_table[xy] & 8)
 825                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 826                     s->current_picture.qscale_table[xy] = s->qscale;
 827
 828                     for (i = 0; i < 6; i++) {
 829                         int dc_pred_dir;
 830                         int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
 831                         if (dc < 0) {
 832                             av_log(s->avctx, AV_LOG_ERROR,
 833                                    "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 834                             return -1;
 835                         }
 836                         dir <<= 1;
 837                         if (dc_pred_dir)
 838                             dir |= 1;
 839                     }
 840                     s->cbp_table[xy]               &= 3;  // remove dquant
 841                     s->cbp_table[xy]               |= cbpy << 2;
 842                     s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
 843                     s->pred_dir_table[xy]           = dir;
 844                 } else if (IS_SKIP(s->current_picture.mb_type[xy])) {
 845                     s->current_picture.qscale_table[xy] = s->qscale;
 846                     s->cbp_table[xy]                    = 0;
 847                 } else {
 848                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 849
 850                     if (cbpy < 0) {
 851                         av_log(s->avctx, AV_LOG_ERROR,
 852                                "P cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 853                         return -1;
 854                     }
 855
 856                     if (s->cbp_table[xy] & 8)
 857                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 858                     s->current_picture.qscale_table[xy] = s->qscale;
 859
 860                     s->cbp_table[xy] &= 3;  // remove dquant
 861                     s->cbp_table[xy] |= (cbpy ^ 0xf) << 2;
 862                 }
 863             }
 864         }
 865         if (mb_num >= mb_count)
 866             return 0;
 867         s->mb_x = 0;
 868     }
 869     return 0;
 870 }
 871
 872 /**
 873  * Decode the first and second partition.
 874  * @return <0 if error (and sets error type in the error_status_table)
 875  */
 876 int ff_mpeg4_decode_partitions(Mpeg4DecContext *ctx)
 877 {
 878     MpegEncContext *s = &ctx->m;
 879     int mb_num;
 880     const int part_a_error = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_ERROR | ER_MV_ERROR) : ER_MV_ERROR;
 881     const int part_a_end   = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_END   | ER_MV_END)   : ER_MV_END;
 882
 883     mb_num = mpeg4_decode_partition_a(ctx);
 884     if (mb_num < 0) {
 885         ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 886                         s->mb_x, s->mb_y, part_a_error);
 887         return -1;
 888     }
 889
 890     if (s->resync_mb_x + s->resync_mb_y * s->mb_width + mb_num > s->mb_num) {
 891         av_log(s->avctx, AV_LOG_ERROR, "slice below monitor ...\n");
 892         ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 893                         s->mb_x, s->mb_y, part_a_error);
 894         return -1;
 895     }
 896
 897     s->mb_num_left = mb_num;
 898
 899     if (s->pict_type == AV_PICTURE_TYPE_I) {
 900         while (show_bits(&s->gb, 9) == 1)
 901             skip_bits(&s->gb, 9);
 902         if (get_bits_long(&s->gb, 19) != DC_MARKER) {
 903             av_log(s->avctx, AV_LOG_ERROR,
 904                    "marker missing after first I partition at %d %d\n",
 905                    s->mb_x, s->mb_y);
 906             return -1;
 907         }
 908     } else {
 909         while (show_bits(&s->gb, 10) == 1)
 910             skip_bits(&s->gb, 10);
 911         if (get_bits(&s->gb, 17) != MOTION_MARKER) {
 912             av_log(s->avctx, AV_LOG_ERROR,
 913                    "marker missing after first P partition at %d %d\n",
 914                    s->mb_x, s->mb_y);
 915             return -1;
 916         }
 917     }
 918     ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 919                     s->mb_x - 1, s->mb_y, part_a_end);
 920
 921     if (mpeg4_decode_partition_b(s, mb_num) < 0) {
 922         if (s->pict_type == AV_PICTURE_TYPE_P)
 923             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 924                             s->mb_x, s->mb_y, ER_DC_ERROR);
 925         return -1;
 926     } else {
 927         if (s->pict_type == AV_PICTURE_TYPE_P)
 928             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 929                             s->mb_x - 1, s->mb_y, ER_DC_END);
 930     }
 931
 932     return 0;
 933 }
 934
 935 /**
 936  * Decode a block.
 937  * @return <0 if an error occurred
 938  */
 939 static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
 940                                      int n, int coded, int intra, int rvlc)
 941 {
 942     MpegEncContext *s = &ctx->m;
 943     int level, i, last, run, qmul, qadd;
 944     int av_uninit(dc_pred_dir);
 945     RLTable *rl;
 946     RL_VLC_ELEM *rl_vlc;
 947     const uint8_t *scan_table;
 948
 949     // Note intra & rvlc should be optimized away if this is inlined
 950
 951     if (intra) {
 952         if (ctx->use_intra_dc_vlc) {
 953             /* DC coef */
 954             if (s->partitioned_frame) {
 955                 level = s->dc_val[0][s->block_index[n]];
 956                 if (n < 4)
 957                     level = FASTDIV((level + (s->y_dc_scale >> 1)), s->y_dc_scale);
 958                 else
 959                     level = FASTDIV((level + (s->c_dc_scale >> 1)), s->c_dc_scale);
 960                 dc_pred_dir = (s->pred_dir_table[s->mb_x + s->mb_y * s->mb_stride] << n) & 32;
 961             } else {
 962                 level = mpeg4_decode_dc(s, n, &dc_pred_dir);
 963                 if (level < 0)
 964                     return -1;
 965             }
 966             block[0] = level;
 967             i        = 0;
 968         } else {
 969             i = -1;
 970             ff_mpeg4_pred_dc(s, n, 0, &dc_pred_dir, 0);
 971         }
 972         if (!coded)
 973             goto not_coded;
 974
 975         if (rvlc) {
 976             rl     = &ff_rvlc_rl_intra;
 977             rl_vlc = ff_rvlc_rl_intra.rl_vlc[0];
 978         } else {
 979             rl     = &ff_mpeg4_rl_intra;
 980             rl_vlc = ff_mpeg4_rl_intra.rl_vlc[0];
 981         }
 982         if (s->ac_pred) {
 983             if (dc_pred_dir == 0)
 984                 scan_table = s->intra_v_scantable.permutated;  /* left */
 985             else
 986                 scan_table = s->intra_h_scantable.permutated;  /* top */
 987         } else {
 988             scan_table = s->intra_scantable.permutated;
 989         }
 990         qmul = 1;
 991         qadd = 0;
 992     } else {
 993         i = -1;
 994         if (!coded) {
 995             s->block_last_index[n] = i;
 996             return 0;
 997         }
 998         if (rvlc)
 999             rl = &ff_rvlc_rl_inter;
1000         else
1001             rl = &ff_h263_rl_inter;
1002
1003         scan_table = s->intra_scantable.permutated;
1004
1005         if (s->mpeg_quant) {
1006             qmul = 1;
1007             qadd = 0;
1008             if (rvlc)
1009                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[0];
1010             else
1011                 rl_vlc = ff_h263_rl_inter.rl_vlc[0];
1012         } else {
1013             qmul = s->qscale << 1;
1014             qadd = (s->qscale - 1) | 1;
1015             if (rvlc)
1016                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[s->qscale];
1017             else
1018                 rl_vlc = ff_h263_rl_inter.rl_vlc[s->qscale];
1019         }
1020     }
1021     {
1022         OPEN_READER(re, &s->gb);
1023         for (;;) {
1024             UPDATE_CACHE(re, &s->gb);
1025             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
1026             if (level == 0) {
1027                 /* escape */
1028                 if (rvlc) {
1029                     if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1030                         av_log(s->avctx, AV_LOG_ERROR,
1031                                "1. marker bit missing in rvlc esc\n");
1032                         return -1;
1033                     }
1034                     SKIP_CACHE(re, &s->gb, 1);
1035
1036                     last = SHOW_UBITS(re, &s->gb, 1);
1037                     SKIP_CACHE(re, &s->gb, 1);
1038                     run = SHOW_UBITS(re, &s->gb, 6);
1039                     SKIP_COUNTER(re, &s->gb, 1 + 1 + 6);
1040                     UPDATE_CACHE(re, &s->gb);
1041
1042                     if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1043                         av_log(s->avctx, AV_LOG_ERROR,
1044                                "2. marker bit missing in rvlc esc\n");
1045                         return -1;
1046                     }
1047                     SKIP_CACHE(re, &s->gb, 1);
1048
1049                     level = SHOW_UBITS(re, &s->gb, 11);
1050                     SKIP_CACHE(re, &s->gb, 11);
1051
1052                     if (SHOW_UBITS(re, &s->gb, 5) != 0x10) {
1053                         av_log(s->avctx, AV_LOG_ERROR, "reverse esc missing\n");
1054                         return -1;
1055                     }
1056                     SKIP_CACHE(re, &s->gb, 5);
1057
1058                     level = level * qmul + qadd;
1059                     level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1060                     SKIP_COUNTER(re, &s->gb, 1 + 11 + 5 + 1);
1061
1062                     i += run + 1;
1063                     if (last)
1064                         i += 192;
1065                 } else {
1066                     int cache;
1067                     cache = GET_CACHE(re, &s->gb);
1068
1069                     if (IS_3IV1)
1070                         cache ^= 0xC0000000;
1071
1072                     if (cache & 0x80000000) {
1073                         if (cache & 0x40000000) {
1074                             /* third escape */
1075                             SKIP_CACHE(re, &s->gb, 2);
1076                             last = SHOW_UBITS(re, &s->gb, 1);
1077                             SKIP_CACHE(re, &s->gb, 1);
1078                             run = SHOW_UBITS(re, &s->gb, 6);
1079                             SKIP_COUNTER(re, &s->gb, 2 + 1 + 6);
1080                             UPDATE_CACHE(re, &s->gb);
1081
1082                             if (IS_3IV1) {
1083                                 level = SHOW_SBITS(re, &s->gb, 12);
1084                                 LAST_SKIP_BITS(re, &s->gb, 12);
1085                             } else {
1086                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1087                                     av_log(s->avctx, AV_LOG_ERROR,
1088                                            "1. marker bit missing in 3. esc\n");
1089                                     if (!(s->err_recognition & AV_EF_IGNORE_ERR))
1090                                         return -1;
1091                                 }
1092                                 SKIP_CACHE(re, &s->gb, 1);
1093
1094                                 level = SHOW_SBITS(re, &s->gb, 12);
1095                                 SKIP_CACHE(re, &s->gb, 12);
1096
1097                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1098                                     av_log(s->avctx, AV_LOG_ERROR,
1099                                            "2. marker bit missing in 3. esc\n");
1100                                     if (!(s->err_recognition & AV_EF_IGNORE_ERR))
1101                                         return -1;
1102                                 }
1103
1104                                 SKIP_COUNTER(re, &s->gb, 1 + 12 + 1);
1105                             }
1106
1107 #if 0
1108                             if (s->error_recognition >= FF_ER_COMPLIANT) {
1109                                 const int abs_level= FFABS(level);
1110                                 if (abs_level<=MAX_LEVEL && run<=MAX_RUN) {
1111                                     const int run1= run - rl->max_run[last][abs_level] - 1;
1112                                     if (abs_level <= rl->max_level[last][run]) {
1113                                         av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, vlc encoding possible\n");
1114                                         return -1;
1115                                     }
1116                                     if (s->error_recognition > FF_ER_COMPLIANT) {
1117                                         if (abs_level <= rl->max_level[last][run]*2) {
1118                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 1 encoding possible\n");
1119                                             return -1;
1120                                         }
1121                                         if (run1 >= 0 && abs_level <= rl->max_level[last][run1]) {
1122                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 2 encoding possible\n");
1123                                             return -1;
1124                                         }
1125                                     }
1126                                 }
1127                             }
1128 #endif
1129                             if (level > 0)
1130                                 level = level * qmul + qadd;
1131                             else
1132                                 level = level * qmul - qadd;
1133
1134                             if ((unsigned)(level + 2048) > 4095) {
1135                                 if (s->err_recognition & (AV_EF_BITSTREAM|AV_EF_AGGRESSIVE)) {
1136                                     if (level > 2560 || level < -2560) {
1137                                         av_log(s->avctx, AV_LOG_ERROR,
1138                                                "|level| overflow in 3. esc, qp=%d\n",
1139                                                s->qscale);
1140                                         return -1;
1141                                     }
1142                                 }
1143                                 level = level < 0 ? -2048 : 2047;
1144                             }
1145
1146                             i += run + 1;
1147                             if (last)
1148                                 i += 192;
1149                         } else {
1150                             /* second escape */
1151                             SKIP_BITS(re, &s->gb, 2);
1152                             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1153                             i    += run + rl->max_run[run >> 7][level / qmul] + 1;  // FIXME opt indexing
1154                             level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1155                             LAST_SKIP_BITS(re, &s->gb, 1);
1156                         }
1157                     } else {
1158                         /* first escape */
1159                         SKIP_BITS(re, &s->gb, 1);
1160                         GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1161                         i    += run;
1162                         level = level + rl->max_level[run >> 7][(run - 1) & 63] * qmul;  // FIXME opt indexing
1163                         level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1164                         LAST_SKIP_BITS(re, &s->gb, 1);
1165                     }
1166                 }
1167             } else {
1168                 i    += run;
1169                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1170                 LAST_SKIP_BITS(re, &s->gb, 1);
1171             }
1172             ff_tlog(s->avctx, "dct[%d][%d] = %- 4d end?:%d\n", scan_table[i&63]&7, scan_table[i&63] >> 3, level, i>62);
1173             if (i > 62) {
1174                 i -= 192;
1175                 if (i & (~63)) {
1176                     av_log(s->avctx, AV_LOG_ERROR,
1177                            "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1178                     return -1;
1179                 }
1180
1181                 block[scan_table[i]] = level;
1182                 break;
1183             }
1184
1185             block[scan_table[i]] = level;
1186         }
1187         CLOSE_READER(re, &s->gb);
1188     }
1189
1190 not_coded:
1191     if (intra) {
1192         if (!ctx->use_intra_dc_vlc) {
1193             block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0);
1194
1195             i -= i >> 31;  // if (i == -1) i = 0;
1196         }
1197
1198         ff_mpeg4_pred_ac(s, block, n, dc_pred_dir);
1199         if (s->ac_pred)
1200             i = 63;  // FIXME not optimal
1201     }
1202     s->block_last_index[n] = i;
1203     return 0;
1204 }
1205
1206 /**
1207  * decode partition C of one MB.
1208  * @return <0 if an error occurred
1209  */
1210 static int mpeg4_decode_partitioned_mb(MpegEncContext *s, int16_t block[6][64])
1211 {
1212     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1213     int cbp, mb_type;
1214     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1215
1216     mb_type = s->current_picture.mb_type[xy];
1217     cbp     = s->cbp_table[xy];
1218
1219     ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1220
1221     if (s->current_picture.qscale_table[xy] != s->qscale)
1222         ff_set_qscale(s, s->current_picture.qscale_table[xy]);
1223
1224     if (s->pict_type == AV_PICTURE_TYPE_P ||
1225         s->pict_type == AV_PICTURE_TYPE_S) {
1226         int i;
1227         for (i = 0; i < 4; i++) {
1228             s->mv[0][i][0] = s->current_picture.motion_val[0][s->block_index[i]][0];
1229             s->mv[0][i][1] = s->current_picture.motion_val[0][s->block_index[i]][1];
1230         }
1231         s->mb_intra = IS_INTRA(mb_type);
1232
1233         if (IS_SKIP(mb_type)) {
1234             /* skip mb */
1235             for (i = 0; i < 6; i++)
1236                 s->block_last_index[i] = -1;
1237             s->mv_dir  = MV_DIR_FORWARD;
1238             s->mv_type = MV_TYPE_16X16;
1239             if (s->pict_type == AV_PICTURE_TYPE_S
1240                 && ctx->vol_sprite_usage == GMC_SPRITE) {
1241                 s->mcsel      = 1;
1242                 s->mb_skipped = 0;
1243             } else {
1244                 s->mcsel      = 0;
1245                 s->mb_skipped = 1;
1246             }
1247         } else if (s->mb_intra) {
1248             s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1249         } else if (!s->mb_intra) {
1250             // s->mcsel = 0;  // FIXME do we need to init that?
1251
1252             s->mv_dir = MV_DIR_FORWARD;
1253             if (IS_8X8(mb_type)) {
1254                 s->mv_type = MV_TYPE_8X8;
1255             } else {
1256                 s->mv_type = MV_TYPE_16X16;
1257             }
1258         }
1259     } else { /* I-Frame */
1260         s->mb_intra = 1;
1261         s->ac_pred  = IS_ACPRED(s->current_picture.mb_type[xy]);
1262     }
1263
1264     if (!IS_SKIP(mb_type)) {
1265         int i;
1266         s->bdsp.clear_blocks(s->block[0]);
1267         /* decode each block */
1268         for (i = 0; i < 6; i++) {
1269             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, s->mb_intra, ctx->rvlc) < 0) {
1270                 av_log(s->avctx, AV_LOG_ERROR,
1271                        "texture corrupted at %d %d %d\n",
1272                        s->mb_x, s->mb_y, s->mb_intra);
1273                 return -1;
1274             }
1275             cbp += cbp;
1276         }
1277     }
1278
1279     /* per-MB end of slice check */
1280     if (--s->mb_num_left <= 0) {
1281         if (mpeg4_is_resync(ctx))
1282             return SLICE_END;
1283         else
1284             return SLICE_NOEND;
1285     } else {
1286         if (mpeg4_is_resync(ctx)) {
1287             const int delta = s->mb_x + 1 == s->mb_width ? 2 : 1;
1288             if (s->cbp_table[xy + delta])
1289                 return SLICE_END;
1290         }
1291         return SLICE_OK;
1292     }
1293 }
1294
1295 static int mpeg4_decode_mb(MpegEncContext *s, int16_t block[6][64])
1296 {
1297     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1298     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
1299     int16_t *mot_val;
1300     static int8_t quant_tab[4] = { -1, -2, 1, 2 };
1301     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1302
1303     av_assert2(s->h263_pred);
1304
1305     if (s->pict_type == AV_PICTURE_TYPE_P ||
1306         s->pict_type == AV_PICTURE_TYPE_S) {
1307         do {
1308             if (get_bits1(&s->gb)) {
1309                 /* skip mb */
1310                 s->mb_intra = 0;
1311                 for (i = 0; i < 6; i++)
1312                     s->block_last_index[i] = -1;
1313                 s->mv_dir  = MV_DIR_FORWARD;
1314                 s->mv_type = MV_TYPE_16X16;
1315                 if (s->pict_type == AV_PICTURE_TYPE_S &&
1316                     ctx->vol_sprite_usage == GMC_SPRITE) {
1317                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1318                                                      MB_TYPE_GMC   |
1319                                                      MB_TYPE_16x16 |
1320                                                      MB_TYPE_L0;
1321                     s->mcsel       = 1;
1322                     s->mv[0][0][0] = get_amv(ctx, 0);
1323                     s->mv[0][0][1] = get_amv(ctx, 1);
1324                     s->mb_skipped  = 0;
1325                 } else {
1326                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1327                                                      MB_TYPE_16x16 |
1328                                                      MB_TYPE_L0;
1329                     s->mcsel       = 0;
1330                     s->mv[0][0][0] = 0;
1331                     s->mv[0][0][1] = 0;
1332                     s->mb_skipped  = 1;
1333                 }
1334                 goto end;
1335             }
1336             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
1337             if (cbpc < 0) {
1338                 av_log(s->avctx, AV_LOG_ERROR,
1339                        "mcbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1340                 return -1;
1341             }
1342         } while (cbpc == 20);
1343
1344         s->bdsp.clear_blocks(s->block[0]);
1345         dquant      = cbpc & 8;
1346         s->mb_intra = ((cbpc & 4) != 0);
1347         if (s->mb_intra)
1348             goto intra;
1349
1350         if (s->pict_type == AV_PICTURE_TYPE_S &&
1351             ctx->vol_sprite_usage == GMC_SPRITE && (cbpc & 16) == 0)
1352             s->mcsel = get_bits1(&s->gb);
1353         else
1354             s->mcsel = 0;
1355         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1) ^ 0x0F;
1356
1357         cbp = (cbpc & 3) | (cbpy << 2);
1358         if (dquant)
1359             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1360         if ((!s->progressive_sequence) &&
1361             (cbp || (s->workaround_bugs & FF_BUG_XVID_ILACE)))
1362             s->interlaced_dct = get_bits1(&s->gb);
1363
1364         s->mv_dir = MV_DIR_FORWARD;
1365         if ((cbpc & 16) == 0) {
1366             if (s->mcsel) {
1367                 s->current_picture.mb_type[xy] = MB_TYPE_GMC   |
1368                                                  MB_TYPE_16x16 |
1369                                                  MB_TYPE_L0;
1370                 /* 16x16 global motion prediction */
1371                 s->mv_type     = MV_TYPE_16X16;
1372                 mx             = get_amv(ctx, 0);
1373                 my             = get_amv(ctx, 1);
1374                 s->mv[0][0][0] = mx;
1375                 s->mv[0][0][1] = my;
1376             } else if ((!s->progressive_sequence) && get_bits1(&s->gb)) {
1377                 s->current_picture.mb_type[xy] = MB_TYPE_16x8 |
1378                                                  MB_TYPE_L0   |
1379                                                  MB_TYPE_INTERLACED;
1380                 /* 16x8 field motion prediction */
1381                 s->mv_type = MV_TYPE_FIELD;
1382
1383                 s->field_select[0][0] = get_bits1(&s->gb);
1384                 s->field_select[0][1] = get_bits1(&s->gb);
1385
1386                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1387
1388                 for (i = 0; i < 2; i++) {
1389                     mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1390                     if (mx >= 0xffff)
1391                         return -1;
1392
1393                     my = ff_h263_decode_motion(s, pred_y / 2, s->f_code);
1394                     if (my >= 0xffff)
1395                         return -1;
1396
1397                     s->mv[0][i][0] = mx;
1398                     s->mv[0][i][1] = my;
1399                 }
1400             } else {
1401                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
1402                 /* 16x16 motion prediction */
1403                 s->mv_type = MV_TYPE_16X16;
1404                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1405                 mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1406
1407                 if (mx >= 0xffff)
1408                     return -1;
1409
1410                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1411
1412                 if (my >= 0xffff)
1413                     return -1;
1414                 s->mv[0][0][0] = mx;
1415                 s->mv[0][0][1] = my;
1416             }
1417         } else {
1418             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
1419             s->mv_type                     = MV_TYPE_8X8;
1420             for (i = 0; i < 4; i++) {
1421                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
1422                 mx      = ff_h263_decode_motion(s, pred_x, s->f_code);
1423                 if (mx >= 0xffff)
1424                     return -1;
1425
1426                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1427                 if (my >= 0xffff)
1428                     return -1;
1429                 s->mv[0][i][0] = mx;
1430                 s->mv[0][i][1] = my;
1431                 mot_val[0]     = mx;
1432                 mot_val[1]     = my;
1433             }
1434         }
1435     } else if (s->pict_type == AV_PICTURE_TYPE_B) {
1436         int modb1;   // first bit of modb
1437         int modb2;   // second bit of modb
1438         int mb_type;
1439
1440         s->mb_intra = 0;  // B-frames never contain intra blocks
1441         s->mcsel    = 0;  //      ...               true gmc blocks
1442
1443         if (s->mb_x == 0) {
1444             for (i = 0; i < 2; i++) {
1445                 s->last_mv[i][0][0] =
1446                 s->last_mv[i][0][1] =
1447                 s->last_mv[i][1][0] =
1448                 s->last_mv[i][1][1] = 0;
1449             }
1450
1451             ff_thread_await_progress(&s->next_picture_ptr->tf, s->mb_y, 0);
1452         }
1453
1454         /* if we skipped it in the future P Frame than skip it now too */
1455         s->mb_skipped = s->next_picture.mbskip_table[s->mb_y * s->mb_stride + s->mb_x];  // Note, skiptab=0 if last was GMC
1456
1457         if (s->mb_skipped) {
1458             /* skip mb */
1459             for (i = 0; i < 6; i++)
1460                 s->block_last_index[i] = -1;
1461
1462             s->mv_dir      = MV_DIR_FORWARD;
1463             s->mv_type     = MV_TYPE_16X16;
1464             s->mv[0][0][0] =
1465             s->mv[0][0][1] =
1466             s->mv[1][0][0] =
1467             s->mv[1][0][1] = 0;
1468             s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1469                                              MB_TYPE_16x16 |
1470                                              MB_TYPE_L0;
1471             goto end;
1472         }
1473
1474         modb1 = get_bits1(&s->gb);
1475         if (modb1) {
1476             // like MB_TYPE_B_DIRECT but no vectors coded
1477             mb_type = MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1;
1478             cbp     = 0;
1479         } else {
1480             modb2   = get_bits1(&s->gb);
1481             mb_type = get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
1482             if (mb_type < 0) {
1483                 av_log(s->avctx, AV_LOG_ERROR, "illegal MB_type\n");
1484                 return -1;
1485             }
1486             mb_type = mb_type_b_map[mb_type];
1487             if (modb2) {
1488                 cbp = 0;
1489             } else {
1490                 s->bdsp.clear_blocks(s->block[0]);
1491                 cbp = get_bits(&s->gb, 6);
1492             }
1493
1494             if ((!IS_DIRECT(mb_type)) && cbp) {
1495                 if (get_bits1(&s->gb))
1496                     ff_set_qscale(s, s->qscale + get_bits1(&s->gb) * 4 - 2);
1497             }
1498
1499             if (!s->progressive_sequence) {
1500                 if (cbp)
1501                     s->interlaced_dct = get_bits1(&s->gb);
1502
1503                 if (!IS_DIRECT(mb_type) && get_bits1(&s->gb)) {
1504                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
1505                     mb_type &= ~MB_TYPE_16x16;
1506
1507                     if (USES_LIST(mb_type, 0)) {
1508                         s->field_select[0][0] = get_bits1(&s->gb);
1509                         s->field_select[0][1] = get_bits1(&s->gb);
1510                     }
1511                     if (USES_LIST(mb_type, 1)) {
1512                         s->field_select[1][0] = get_bits1(&s->gb);
1513                         s->field_select[1][1] = get_bits1(&s->gb);
1514                     }
1515                 }
1516             }
1517
1518             s->mv_dir = 0;
1519             if ((mb_type & (MB_TYPE_DIRECT2 | MB_TYPE_INTERLACED)) == 0) {
1520                 s->mv_type = MV_TYPE_16X16;
1521
1522                 if (USES_LIST(mb_type, 0)) {
1523                     s->mv_dir = MV_DIR_FORWARD;
1524
1525                     mx = ff_h263_decode_motion(s, s->last_mv[0][0][0], s->f_code);
1526                     my = ff_h263_decode_motion(s, s->last_mv[0][0][1], s->f_code);
1527                     s->last_mv[0][1][0] =
1528                     s->last_mv[0][0][0] =
1529                     s->mv[0][0][0]      = mx;
1530                     s->last_mv[0][1][1] =
1531                     s->last_mv[0][0][1] =
1532                     s->mv[0][0][1]      = my;
1533                 }
1534
1535                 if (USES_LIST(mb_type, 1)) {
1536                     s->mv_dir |= MV_DIR_BACKWARD;
1537
1538                     mx = ff_h263_decode_motion(s, s->last_mv[1][0][0], s->b_code);
1539                     my = ff_h263_decode_motion(s, s->last_mv[1][0][1], s->b_code);
1540                     s->last_mv[1][1][0] =
1541                     s->last_mv[1][0][0] =
1542                     s->mv[1][0][0]      = mx;
1543                     s->last_mv[1][1][1] =
1544                     s->last_mv[1][0][1] =
1545                     s->mv[1][0][1]      = my;
1546                 }
1547             } else if (!IS_DIRECT(mb_type)) {
1548                 s->mv_type = MV_TYPE_FIELD;
1549
1550                 if (USES_LIST(mb_type, 0)) {
1551                     s->mv_dir = MV_DIR_FORWARD;
1552
1553                     for (i = 0; i < 2; i++) {
1554                         mx = ff_h263_decode_motion(s, s->last_mv[0][i][0], s->f_code);
1555                         my = ff_h263_decode_motion(s, s->last_mv[0][i][1] / 2, s->f_code);
1556                         s->last_mv[0][i][0] =
1557                         s->mv[0][i][0]      = mx;
1558                         s->last_mv[0][i][1] = (s->mv[0][i][1] = my) * 2;
1559                     }
1560                 }
1561
1562                 if (USES_LIST(mb_type, 1)) {
1563                     s->mv_dir |= MV_DIR_BACKWARD;
1564
1565                     for (i = 0; i < 2; i++) {
1566                         mx = ff_h263_decode_motion(s, s->last_mv[1][i][0], s->b_code);
1567                         my = ff_h263_decode_motion(s, s->last_mv[1][i][1] / 2, s->b_code);
1568                         s->last_mv[1][i][0] =
1569                         s->mv[1][i][0]      = mx;
1570                         s->last_mv[1][i][1] = (s->mv[1][i][1] = my) * 2;
1571                     }
1572                 }
1573             }
1574         }
1575
1576         if (IS_DIRECT(mb_type)) {
1577             if (IS_SKIP(mb_type)) {
1578                 mx =
1579                 my = 0;
1580             } else {
1581                 mx = ff_h263_decode_motion(s, 0, 1);
1582                 my = ff_h263_decode_motion(s, 0, 1);
1583             }
1584
1585             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
1586             mb_type  |= ff_mpeg4_set_direct_mv(s, mx, my);
1587         }
1588         s->current_picture.mb_type[xy] = mb_type;
1589     } else { /* I-Frame */
1590         do {
1591             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
1592             if (cbpc < 0) {
1593                 av_log(s->avctx, AV_LOG_ERROR,
1594                        "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1595                 return -1;
1596             }
1597         } while (cbpc == 8);
1598
1599         dquant = cbpc & 4;
1600         s->mb_intra = 1;
1601
1602 intra:
1603         s->ac_pred = get_bits1(&s->gb);
1604         if (s->ac_pred)
1605             s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
1606         else
1607             s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
1608
1609         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
1610         if (cbpy < 0) {
1611             av_log(s->avctx, AV_LOG_ERROR,
1612                    "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
1613             return -1;
1614         }
1615         cbp = (cbpc & 3) | (cbpy << 2);
1616
1617         ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1618
1619         if (dquant)
1620             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1621
1622         if (!s->progressive_sequence)
1623             s->interlaced_dct = get_bits1(&s->gb);
1624
1625         s->bdsp.clear_blocks(s->block[0]);
1626         /* decode each block */
1627         for (i = 0; i < 6; i++) {
1628             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 1, 0) < 0)
1629                 return -1;
1630             cbp += cbp;
1631         }
1632         goto end;
1633     }
1634
1635     /* decode each block */
1636     for (i = 0; i < 6; i++) {
1637         if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 0, 0) < 0)
1638             return -1;
1639         cbp += cbp;
1640     }
1641
1642 end:
1643     /* per-MB end of slice check */
1644     if (s->codec_id == AV_CODEC_ID_MPEG4) {
1645         int next = mpeg4_is_resync(ctx);
1646         if (next) {
1647             if        (s->mb_x + s->mb_y*s->mb_width + 1 >  next && (s->avctx->err_recognition & AV_EF_AGGRESSIVE)) {
1648                 return -1;
1649             } else if (s->mb_x + s->mb_y*s->mb_width + 1 >= next)
1650                 return SLICE_END;
1651
1652             if (s->pict_type == AV_PICTURE_TYPE_B) {
1653                 const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1654                 ff_thread_await_progress(&s->next_picture_ptr->tf,
1655                                          (s->mb_x + delta >= s->mb_width)
1656                                          ? FFMIN(s->mb_y + 1, s->mb_height - 1)
1657                                          : s->mb_y, 0);
1658                 if (s->next_picture.mbskip_table[xy + delta])
1659                     return SLICE_OK;
1660             }
1661
1662             return SLICE_END;
1663         }
1664     }
1665
1666     return SLICE_OK;
1667 }
1668
1669 static int mpeg4_decode_gop_header(MpegEncContext *s, GetBitContext *gb)
1670 {
1671     int hours, minutes, seconds;
1672
1673     if (!show_bits(gb, 23)) {
1674         av_log(s->avctx, AV_LOG_WARNING, "GOP header invalid\n");
1675         return -1;
1676     }
1677
1678     hours   = get_bits(gb, 5);
1679     minutes = get_bits(gb, 6);
1680     check_marker(gb, "in gop_header");
1681     seconds = get_bits(gb, 6);
1682
1683     s->time_base = seconds + 60*(minutes + 60*hours);
1684
1685     skip_bits1(gb);
1686     skip_bits1(gb);
1687
1688     return 0;
1689 }
1690
1691 static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb)
1692 {
1693
1694     s->avctx->profile = get_bits(gb, 4);
1695     s->avctx->level   = get_bits(gb, 4);
1696
1697     // for Simple profile, level 0
1698     if (s->avctx->profile == 0 && s->avctx->level == 8) {
1699         s->avctx->level = 0;
1700     }
1701
1702     return 0;
1703 }
1704
1705 static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
1706 {
1707     MpegEncContext *s = &ctx->m;
1708     int width, height, vo_ver_id;
1709
1710     /* vol header */
1711     skip_bits(gb, 1);                   /* random access */
1712     s->vo_type = get_bits(gb, 8);
1713     if (get_bits1(gb) != 0) {           /* is_ol_id */
1714         vo_ver_id = get_bits(gb, 4);    /* vo_ver_id */
1715         skip_bits(gb, 3);               /* vo_priority */
1716     } else {
1717         vo_ver_id = 1;
1718     }
1719     s->aspect_ratio_info = get_bits(gb, 4);
1720     if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1721         s->avctx->sample_aspect_ratio.num = get_bits(gb, 8);  // par_width
1722         s->avctx->sample_aspect_ratio.den = get_bits(gb, 8);  // par_height
1723     } else {
1724         s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[s->aspect_ratio_info];
1725     }
1726
1727     if ((ctx->vol_control_parameters = get_bits1(gb))) { /* vol control parameter */
1728         int chroma_format = get_bits(gb, 2);
1729         if (chroma_format != CHROMA_420)
1730             av_log(s->avctx, AV_LOG_ERROR, "illegal chroma format\n");
1731
1732         s->low_delay = get_bits1(gb);
1733         if (get_bits1(gb)) {    /* vbv parameters */
1734             get_bits(gb, 15);   /* first_half_bitrate */
1735             check_marker(gb, "after first_half_bitrate");
1736             get_bits(gb, 15);   /* latter_half_bitrate */
1737             check_marker(gb, "after latter_half_bitrate");
1738             get_bits(gb, 15);   /* first_half_vbv_buffer_size */
1739             check_marker(gb, "after first_half_vbv_buffer_size");
1740             get_bits(gb, 3);    /* latter_half_vbv_buffer_size */
1741             get_bits(gb, 11);   /* first_half_vbv_occupancy */
1742             check_marker(gb, "after first_half_vbv_occupancy");
1743             get_bits(gb, 15);   /* latter_half_vbv_occupancy */
1744             check_marker(gb, "after latter_half_vbv_occupancy");
1745         }
1746     } else {
1747         /* is setting low delay flag only once the smartest thing to do?
1748          * low delay detection won't be overridden. */
1749         if (s->picture_number == 0)
1750             s->low_delay = 0;
1751     }
1752
1753     ctx->shape = get_bits(gb, 2); /* vol shape */
1754     if (ctx->shape != RECT_SHAPE)
1755         av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
1756     if (ctx->shape == GRAY_SHAPE && vo_ver_id != 1) {
1757         av_log(s->avctx, AV_LOG_ERROR, "Gray shape not supported\n");
1758         skip_bits(gb, 4);  /* video_object_layer_shape_extension */
1759     }
1760
1761     check_marker(gb, "before time_increment_resolution");
1762
1763     s->avctx->framerate.num = get_bits(gb, 16);
1764     if (!s->avctx->framerate.num) {
1765         av_log(s->avctx, AV_LOG_ERROR, "framerate==0\n");
1766         return AVERROR_INVALIDDATA;
1767     }
1768
1769     ctx->time_increment_bits = av_log2(s->avctx->framerate.num - 1) + 1;
1770     if (ctx->time_increment_bits < 1)
1771         ctx->time_increment_bits = 1;
1772
1773     check_marker(gb, "before fixed_vop_rate");
1774
1775     if (get_bits1(gb) != 0)     /* fixed_vop_rate  */
1776         s->avctx->framerate.den = get_bits(gb, ctx->time_increment_bits);
1777     else
1778         s->avctx->framerate.den = 1;
1779
1780     s->avctx->time_base = av_inv_q(av_mul_q(s->avctx->framerate, (AVRational){s->avctx->ticks_per_frame, 1}));
1781
1782     ctx->t_frame = 0;
1783
1784     if (ctx->shape != BIN_ONLY_SHAPE) {
1785         if (ctx->shape == RECT_SHAPE) {
1786             check_marker(gb, "before width");
1787             width = get_bits(gb, 13);
1788             check_marker(gb, "before height");
1789             height = get_bits(gb, 13);
1790             check_marker(gb, "after height");
1791             if (width && height &&  /* they should be non zero but who knows */
1792                 !(s->width && s->codec_tag == AV_RL32("MP4S"))) {
1793                 if (s->width && s->height &&
1794                     (s->width != width || s->height != height))
1795                     s->context_reinit = 1;
1796                 s->width  = width;
1797                 s->height = height;
1798             }
1799         }
1800
1801         s->progressive_sequence  =
1802         s->progressive_frame     = get_bits1(gb) ^ 1;
1803         s->interlaced_dct        = 0;
1804         if (!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
1805             av_log(s->avctx, AV_LOG_INFO,           /* OBMC Disable */
1806                    "MPEG4 OBMC not supported (very likely buggy encoder)\n");
1807         if (vo_ver_id == 1)
1808             ctx->vol_sprite_usage = get_bits1(gb);    /* vol_sprite_usage */
1809         else
1810             ctx->vol_sprite_usage = get_bits(gb, 2);  /* vol_sprite_usage */
1811
1812         if (ctx->vol_sprite_usage == STATIC_SPRITE)
1813             av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
1814         if (ctx->vol_sprite_usage == STATIC_SPRITE ||
1815             ctx->vol_sprite_usage == GMC_SPRITE) {
1816             if (ctx->vol_sprite_usage == STATIC_SPRITE) {
1817                 skip_bits(gb, 13); // sprite_width
1818                 check_marker(gb, "after sprite_width");
1819                 skip_bits(gb, 13); // sprite_height
1820                 check_marker(gb, "after sprite_height");
1821                 skip_bits(gb, 13); // sprite_left
1822                 check_marker(gb, "after sprite_left");
1823                 skip_bits(gb, 13); // sprite_top
1824                 check_marker(gb, "after sprite_top");
1825             }
1826             ctx->num_sprite_warping_points = get_bits(gb, 6);
1827             if (ctx->num_sprite_warping_points > 3) {
1828                 av_log(s->avctx, AV_LOG_ERROR,
1829                        "%d sprite_warping_points\n",
1830                        ctx->num_sprite_warping_points);
1831                 ctx->num_sprite_warping_points = 0;
1832                 return AVERROR_INVALIDDATA;
1833             }
1834             s->sprite_warping_accuracy  = get_bits(gb, 2);
1835             ctx->sprite_brightness_change = get_bits1(gb);
1836             if (ctx->vol_sprite_usage == STATIC_SPRITE)
1837                 skip_bits1(gb); // low_latency_sprite
1838         }
1839         // FIXME sadct disable bit if verid!=1 && shape not rect
1840
1841         if (get_bits1(gb) == 1) {                   /* not_8_bit */
1842             s->quant_precision = get_bits(gb, 4);   /* quant_precision */
1843             if (get_bits(gb, 4) != 8)               /* bits_per_pixel */
1844                 av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n");
1845             if (s->quant_precision != 5)
1846                 av_log(s->avctx, AV_LOG_ERROR,
1847                        "quant precision %d\n", s->quant_precision);
1848             if (s->quant_precision<3 || s->quant_precision>9) {
1849                 s->quant_precision = 5;
1850             }
1851         } else {
1852             s->quant_precision = 5;
1853         }
1854
1855         // FIXME a bunch of grayscale shape things
1856
1857         if ((s->mpeg_quant = get_bits1(gb))) { /* vol_quant_type */
1858             int i, v;
1859
1860             /* load default matrixes */
1861             for (i = 0; i < 64; i++) {
1862                 int j = s->idsp.idct_permutation[i];
1863                 v = ff_mpeg4_default_intra_matrix[i];
1864                 s->intra_matrix[j]        = v;
1865                 s->chroma_intra_matrix[j] = v;
1866
1867                 v = ff_mpeg4_default_non_intra_matrix[i];
1868                 s->inter_matrix[j]        = v;
1869                 s->chroma_inter_matrix[j] = v;
1870             }
1871
1872             /* load custom intra matrix */
1873             if (get_bits1(gb)) {
1874                 int last = 0;
1875                 for (i = 0; i < 64; i++) {
1876                     int j;
1877                     v = get_bits(gb, 8);
1878                     if (v == 0)
1879                         break;
1880
1881                     last = v;
1882                     j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1883                     s->intra_matrix[j]        = last;
1884                     s->chroma_intra_matrix[j] = last;
1885                 }
1886
1887                 /* replicate last value */
1888                 for (; i < 64; i++) {
1889                     int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1890                     s->intra_matrix[j]        = last;
1891                     s->chroma_intra_matrix[j] = last;
1892                 }
1893             }
1894
1895             /* load custom non intra matrix */
1896             if (get_bits1(gb)) {
1897                 int last = 0;
1898                 for (i = 0; i < 64; i++) {
1899                     int j;
1900                     v = get_bits(gb, 8);
1901                     if (v == 0)
1902                         break;
1903
1904                     last = v;
1905                     j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1906                     s->inter_matrix[j]        = v;
1907                     s->chroma_inter_matrix[j] = v;
1908                 }
1909
1910                 /* replicate last value */
1911                 for (; i < 64; i++) {
1912                     int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1913                     s->inter_matrix[j]        = last;
1914                     s->chroma_inter_matrix[j] = last;
1915                 }
1916             }
1917
1918             // FIXME a bunch of grayscale shape things
1919         }
1920
1921         if (vo_ver_id != 1)
1922             s->quarter_sample = get_bits1(gb);
1923         else
1924             s->quarter_sample = 0;
1925
1926         if (get_bits_left(gb) < 4) {
1927             av_log(s->avctx, AV_LOG_ERROR, "VOL Header truncated\n");
1928             return AVERROR_INVALIDDATA;
1929         }
1930
1931         if (!get_bits1(gb)) {
1932             int pos               = get_bits_count(gb);
1933             int estimation_method = get_bits(gb, 2);
1934             if (estimation_method < 2) {
1935                 if (!get_bits1(gb)) {
1936                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* opaque */
1937                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* transparent */
1938                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_cae */
1939                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* inter_cae */
1940                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* no_update */
1941                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* upampling */
1942                 }
1943                 if (!get_bits1(gb)) {
1944                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_blocks */
1945                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter_blocks */
1946                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter4v_blocks */
1947                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* not coded blocks */
1948                 }
1949                 if (!check_marker(gb, "in complexity estimation part 1")) {
1950                     skip_bits_long(gb, pos - get_bits_count(gb));
1951                     goto no_cplx_est;
1952                 }
1953                 if (!get_bits1(gb)) {
1954                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_coeffs */
1955                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_lines */
1956                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* vlc_syms */
1957                     ctx->cplx_estimation_trash_i += 4 * get_bits1(gb);  /* vlc_bits */
1958                 }
1959                 if (!get_bits1(gb)) {
1960                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* apm */
1961                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* npm */
1962                     ctx->cplx_estimation_trash_b += 8 * get_bits1(gb);  /* interpolate_mc_q */
1963                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* forwback_mc_q */
1964                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel2 */
1965                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel4 */
1966                 }
1967                 if (!check_marker(gb, "in complexity estimation part 2")) {
1968                     skip_bits_long(gb, pos - get_bits_count(gb));
1969                     goto no_cplx_est;
1970                 }
1971                 if (estimation_method == 1) {
1972                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* sadct */
1973                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* qpel */
1974                 }
1975             } else
1976                 av_log(s->avctx, AV_LOG_ERROR,
1977                        "Invalid Complexity estimation method %d\n",
1978                        estimation_method);
1979         } else {
1980
1981 no_cplx_est:
1982             ctx->cplx_estimation_trash_i =
1983             ctx->cplx_estimation_trash_p =
1984             ctx->cplx_estimation_trash_b = 0;
1985         }
1986
1987         ctx->resync_marker = !get_bits1(gb); /* resync_marker_disabled */
1988
1989         s->data_partitioning = get_bits1(gb);
1990         if (s->data_partitioning)
1991             ctx->rvlc = get_bits1(gb);
1992
1993         if (vo_ver_id != 1) {
1994             ctx->new_pred = get_bits1(gb);
1995             if (ctx->new_pred) {
1996                 av_log(s->avctx, AV_LOG_ERROR, "new pred not supported\n");
1997                 skip_bits(gb, 2); /* requested upstream message type */
1998                 skip_bits1(gb);   /* newpred segment type */
1999             }
2000             if (get_bits1(gb)) // reduced_res_vop
2001                 av_log(s->avctx, AV_LOG_ERROR,
2002                        "reduced resolution VOP not supported\n");
2003         } else {
2004             ctx->new_pred = 0;
2005         }
2006
2007         ctx->scalability = get_bits1(gb);
2008
2009         if (ctx->scalability) {
2010             GetBitContext bak = *gb;
2011             int h_sampling_factor_n;
2012             int h_sampling_factor_m;
2013             int v_sampling_factor_n;
2014             int v_sampling_factor_m;
2015
2016             skip_bits1(gb);    // hierarchy_type
2017             skip_bits(gb, 4);  /* ref_layer_id */
2018             skip_bits1(gb);    /* ref_layer_sampling_dir */
2019             h_sampling_factor_n = get_bits(gb, 5);
2020             h_sampling_factor_m = get_bits(gb, 5);
2021             v_sampling_factor_n = get_bits(gb, 5);
2022             v_sampling_factor_m = get_bits(gb, 5);
2023             ctx->enhancement_type = get_bits1(gb);
2024
2025             if (h_sampling_factor_n == 0 || h_sampling_factor_m == 0 ||
2026                 v_sampling_factor_n == 0 || v_sampling_factor_m == 0) {
2027                 /* illegal scalability header (VERY broken encoder),
2028                  * trying to workaround */
2029                 ctx->scalability = 0;
2030                 *gb            = bak;
2031             } else
2032                 av_log(s->avctx, AV_LOG_ERROR, "scalability not supported\n");
2033
2034             // bin shape stuff FIXME
2035         }
2036     }
2037
2038     if (s->avctx->debug&FF_DEBUG_PICT_INFO) {
2039         av_log(s->avctx, AV_LOG_DEBUG, "tb %d/%d, tincrbits:%d, qp_prec:%d, ps:%d,  %s%s%s%s\n",
2040                s->avctx->framerate.den, s->avctx->framerate.num,
2041                ctx->time_increment_bits,
2042                s->quant_precision,
2043                s->progressive_sequence,
2044                ctx->scalability ? "scalability " :"" , s->quarter_sample ? "qpel " : "",
2045                s->data_partitioning ? "partition " : "", ctx->rvlc ? "rvlc " : ""
2046         );
2047     }
2048
2049     return 0;
2050 }
2051
2052 /**
2053  * Decode the user data stuff in the header.
2054  * Also initializes divx/xvid/lavc_version/build.
2055  */
2056 static int decode_user_data(Mpeg4DecContext *ctx, GetBitContext *gb)
2057 {
2058     MpegEncContext *s = &ctx->m;
2059     char buf[256];
2060     int i;
2061     int e;
2062     int ver = 0, build = 0, ver2 = 0, ver3 = 0;
2063     char last;
2064
2065     for (i = 0; i < 255 && get_bits_count(gb) < gb->size_in_bits; i++) {
2066         if (show_bits(gb, 23) == 0)
2067             break;
2068         buf[i] = get_bits(gb, 8);
2069     }
2070     buf[i] = 0;
2071
2072     /* divx detection */
2073     e = sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
2074     if (e < 2)
2075         e = sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
2076     if (e >= 2) {
2077         ctx->divx_version = ver;
2078         ctx->divx_build   = build;
2079         s->divx_packed  = e == 3 && last == 'p';
2080     }
2081
2082     /* libavcodec detection */
2083     e = sscanf(buf, "FFmpe%*[^b]b%d", &build) + 3;
2084     if (e != 4)
2085         e = sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
2086     if (e != 4) {
2087         e = sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3) + 1;
2088         if (e > 1)
2089             build = (ver << 16) + (ver2 << 8) + ver3;
2090     }
2091     if (e != 4) {
2092         if (strcmp(buf, "ffmpeg") == 0)
2093             ctx->lavc_build = 4600;
2094     }
2095     if (e == 4)
2096         ctx->lavc_build = build;
2097
2098     /* Xvid detection */
2099     e = sscanf(buf, "XviD%d", &build);
2100     if (e == 1)
2101         ctx->xvid_build = build;
2102
2103     return 0;
2104 }
2105
2106 int ff_mpeg4_workaround_bugs(AVCodecContext *avctx)
2107 {
2108     Mpeg4DecContext *ctx = avctx->priv_data;
2109     MpegEncContext *s = &ctx->m;
2110
2111     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1) {
2112         if (s->codec_tag        == AV_RL32("XVID") ||
2113             s->codec_tag        == AV_RL32("XVIX") ||
2114             s->codec_tag        == AV_RL32("RMP4") ||
2115             s->codec_tag        == AV_RL32("ZMP4") ||
2116             s->codec_tag        == AV_RL32("SIPP"))
2117             ctx->xvid_build = 0;
2118     }
2119
2120     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1)
2121         if (s->codec_tag == AV_RL32("DIVX") && s->vo_type == 0 &&
2122             ctx->vol_control_parameters == 0)
2123             ctx->divx_version = 400;  // divx 4
2124
2125     if (ctx->xvid_build >= 0 && ctx->divx_version >= 0) {
2126         ctx->divx_version =
2127         ctx->divx_build   = -1;
2128     }
2129
2130     if (s->workaround_bugs & FF_BUG_AUTODETECT) {
2131         if (s->codec_tag == AV_RL32("XVIX"))
2132             s->workaround_bugs |= FF_BUG_XVID_ILACE;
2133
2134         if (s->codec_tag == AV_RL32("UMP4"))
2135             s->workaround_bugs |= FF_BUG_UMP4;
2136
2137         if (ctx->divx_version >= 500 && ctx->divx_build < 1814)
2138             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2139
2140         if (ctx->divx_version > 502 && ctx->divx_build < 1814)
2141             s->workaround_bugs |= FF_BUG_QPEL_CHROMA2;
2142
2143         if (ctx->xvid_build <= 3U)
2144             s->padding_bug_score = 256 * 256 * 256 * 64;
2145
2146         if (ctx->xvid_build <= 1U)
2147             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2148
2149         if (ctx->xvid_build <= 12U)
2150             s->workaround_bugs |= FF_BUG_EDGE;
2151
2152         if (ctx->xvid_build <= 32U)
2153             s->workaround_bugs |= FF_BUG_DC_CLIP;
2154
2155 #define SET_QPEL_FUNC(postfix1, postfix2)                           \
2156     s->qdsp.put_        ## postfix1 = ff_put_        ## postfix2;   \
2157     s->qdsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;   \
2158     s->qdsp.avg_        ## postfix1 = ff_avg_        ## postfix2;
2159
2160         if (ctx->lavc_build < 4653U)
2161             s->workaround_bugs |= FF_BUG_STD_QPEL;
2162
2163         if (ctx->lavc_build < 4655U)
2164             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2165
2166         if (ctx->lavc_build < 4670U)
2167             s->workaround_bugs |= FF_BUG_EDGE;
2168
2169         if (ctx->lavc_build <= 4712U)
2170             s->workaround_bugs |= FF_BUG_DC_CLIP;
2171
2172         if (ctx->divx_version >= 0)
2173             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2174         if (ctx->divx_version == 501 && ctx->divx_build == 20020416)
2175             s->padding_bug_score = 256 * 256 * 256 * 64;
2176
2177         if (ctx->divx_version < 500U)
2178             s->workaround_bugs |= FF_BUG_EDGE;
2179
2180         if (ctx->divx_version >= 0)
2181             s->workaround_bugs |= FF_BUG_HPEL_CHROMA;
2182     }
2183
2184     if (s->workaround_bugs & FF_BUG_STD_QPEL) {
2185         SET_QPEL_FUNC(qpel_pixels_tab[0][5], qpel16_mc11_old_c)
2186         SET_QPEL_FUNC(qpel_pixels_tab[0][7], qpel16_mc31_old_c)
2187         SET_QPEL_FUNC(qpel_pixels_tab[0][9], qpel16_mc12_old_c)
2188         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
2189         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
2190         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
2191
2192         SET_QPEL_FUNC(qpel_pixels_tab[1][5], qpel8_mc11_old_c)
2193         SET_QPEL_FUNC(qpel_pixels_tab[1][7], qpel8_mc31_old_c)
2194         SET_QPEL_FUNC(qpel_pixels_tab[1][9], qpel8_mc12_old_c)
2195         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
2196         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
2197         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
2198     }
2199
2200     if (avctx->debug & FF_DEBUG_BUGS)
2201         av_log(s->avctx, AV_LOG_DEBUG,
2202                "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
2203                s->workaround_bugs, ctx->lavc_build, ctx->xvid_build,
2204                ctx->divx_version, ctx->divx_build, s->divx_packed ? "p" : "");
2205
2206     if (CONFIG_MPEG4_DECODER && ctx->xvid_build >= 0 &&
2207         s->codec_id == AV_CODEC_ID_MPEG4 &&
2208         avctx->idct_algo == FF_IDCT_AUTO) {
2209         avctx->idct_algo = FF_IDCT_XVID;
2210         ff_mpv_idct_init(s);
2211         return 1;
2212     }
2213
2214     return 0;
2215 }
2216
2217 static int decode_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2218 {
2219     MpegEncContext *s = &ctx->m;
2220     int time_incr, time_increment;
2221     int64_t pts;
2222
2223     s->pict_type = get_bits(gb, 2) + AV_PICTURE_TYPE_I;        /* pict type: I = 0 , P = 1 */
2224     if (s->pict_type == AV_PICTURE_TYPE_B && s->low_delay &&
2225         ctx->vol_control_parameters == 0 && !(s->flags & CODEC_FLAG_LOW_DELAY)) {
2226         av_log(s->avctx, AV_LOG_ERROR, "low_delay flag set incorrectly, clearing it\n");
2227         s->low_delay = 0;
2228     }
2229
2230     s->partitioned_frame = s->data_partitioning && s->pict_type != AV_PICTURE_TYPE_B;
2231     if (s->partitioned_frame)
2232         s->decode_mb = mpeg4_decode_partitioned_mb;
2233     else
2234         s->decode_mb = mpeg4_decode_mb;
2235
2236     time_incr = 0;
2237     while (get_bits1(gb) != 0)
2238         time_incr++;
2239
2240     check_marker(gb, "before time_increment");
2241
2242     if (ctx->time_increment_bits == 0 ||
2243         !(show_bits(gb, ctx->time_increment_bits + 1) & 1)) {
2244         av_log(s->avctx, AV_LOG_WARNING,
2245                "time_increment_bits %d is invalid in relation to the current bitstream, this is likely caused by a missing VOL header\n", ctx->time_increment_bits);
2246
2247         for (ctx->time_increment_bits = 1;
2248              ctx->time_increment_bits < 16;
2249              ctx->time_increment_bits++) {
2250             if (s->pict_type == AV_PICTURE_TYPE_P ||
2251                 (s->pict_type == AV_PICTURE_TYPE_S &&
2252                  ctx->vol_sprite_usage == GMC_SPRITE)) {
2253                 if ((show_bits(gb, ctx->time_increment_bits + 6) & 0x37) == 0x30)
2254                     break;
2255             } else if ((show_bits(gb, ctx->time_increment_bits + 5) & 0x1F) == 0x18)
2256                 break;
2257         }
2258
2259         av_log(s->avctx, AV_LOG_WARNING,
2260                "time_increment_bits set to %d bits, based on bitstream analysis\n", ctx->time_increment_bits);
2261         if (s->avctx->framerate.num && 4*s->avctx->framerate.num < 1<<ctx->time_increment_bits) {
2262             s->avctx->framerate.num = 1<<ctx->time_increment_bits;
2263             s->avctx->time_base = av_inv_q(av_mul_q(s->avctx->framerate, (AVRational){s->avctx->ticks_per_frame, 1}));
2264         }
2265     }
2266
2267     if (IS_3IV1)
2268         time_increment = get_bits1(gb);        // FIXME investigate further
2269     else
2270         time_increment = get_bits(gb, ctx->time_increment_bits);
2271
2272     if (s->pict_type != AV_PICTURE_TYPE_B) {
2273         s->last_time_base = s->time_base;
2274         s->time_base     += time_incr;
2275         s->time = s->time_base * s->avctx->framerate.num + time_increment;
2276         if (s->workaround_bugs & FF_BUG_UMP4) {
2277             if (s->time < s->last_non_b_time) {
2278                 /* header is not mpeg-4-compatible, broken encoder,
2279                  * trying to workaround */
2280                 s->time_base++;
2281                 s->time += s->avctx->framerate.num;
2282             }
2283         }
2284         s->pp_time         = s->time - s->last_non_b_time;
2285         s->last_non_b_time = s->time;
2286     } else {
2287         s->time    = (s->last_time_base + time_incr) * s->avctx->framerate.num + time_increment;
2288         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
2289         if (s->pp_time <= s->pb_time ||
2290             s->pp_time <= s->pp_time - s->pb_time ||
2291             s->pp_time <= 0) {
2292             /* messed up order, maybe after seeking? skipping current b-frame */
2293             return FRAME_SKIPPED;
2294         }
2295         ff_mpeg4_init_direct_mv(s);
2296
2297         if (ctx->t_frame == 0)
2298             ctx->t_frame = s->pb_time;
2299         if (ctx->t_frame == 0)
2300             ctx->t_frame = 1;  // 1/0 protection
2301         s->pp_field_time = (ROUNDED_DIV(s->last_non_b_time, ctx->t_frame) -
2302                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2303         s->pb_field_time = (ROUNDED_DIV(s->time, ctx->t_frame) -
2304                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2305         if (s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1) {
2306             s->pb_field_time = 2;
2307             s->pp_field_time = 4;
2308             if (!s->progressive_sequence)
2309                 return FRAME_SKIPPED;
2310         }
2311     }
2312
2313     if (s->avctx->framerate.den)
2314         pts = ROUNDED_DIV(s->time, s->avctx->framerate.den);
2315     else
2316         pts = AV_NOPTS_VALUE;
2317     if (s->avctx->debug&FF_DEBUG_PTS)
2318         av_log(s->avctx, AV_LOG_DEBUG, "MPEG4 PTS: %"PRId64"\n",
2319                pts);
2320
2321     check_marker(gb, "before vop_coded");
2322
2323     /* vop coded */
2324     if (get_bits1(gb) != 1) {
2325         if (s->avctx->debug & FF_DEBUG_PICT_INFO)
2326             av_log(s->avctx, AV_LOG_ERROR, "vop not coded\n");
2327         return FRAME_SKIPPED;
2328     }
2329     if (ctx->new_pred)
2330         decode_new_pred(ctx, gb);
2331
2332     if (ctx->shape != BIN_ONLY_SHAPE &&
2333                     (s->pict_type == AV_PICTURE_TYPE_P ||
2334                      (s->pict_type == AV_PICTURE_TYPE_S &&
2335                       ctx->vol_sprite_usage == GMC_SPRITE))) {
2336         /* rounding type for motion estimation */
2337         s->no_rounding = get_bits1(gb);
2338     } else {
2339         s->no_rounding = 0;
2340     }
2341     // FIXME reduced res stuff
2342
2343     if (ctx->shape != RECT_SHAPE) {
2344         if (ctx->vol_sprite_usage != 1 || s->pict_type != AV_PICTURE_TYPE_I) {
2345             skip_bits(gb, 13);  /* width */
2346             check_marker(gb, "after width");
2347             skip_bits(gb, 13);  /* height */
2348             check_marker(gb, "after height");
2349             skip_bits(gb, 13);  /* hor_spat_ref */
2350             check_marker(gb, "after hor_spat_ref");
2351             skip_bits(gb, 13);  /* ver_spat_ref */
2352         }
2353         skip_bits1(gb);         /* change_CR_disable */
2354
2355         if (get_bits1(gb) != 0)
2356             skip_bits(gb, 8);   /* constant_alpha_value */
2357     }
2358
2359     // FIXME complexity estimation stuff
2360
2361     if (ctx->shape != BIN_ONLY_SHAPE) {
2362         skip_bits_long(gb, ctx->cplx_estimation_trash_i);
2363         if (s->pict_type != AV_PICTURE_TYPE_I)
2364             skip_bits_long(gb, ctx->cplx_estimation_trash_p);
2365         if (s->pict_type == AV_PICTURE_TYPE_B)
2366             skip_bits_long(gb, ctx->cplx_estimation_trash_b);
2367
2368         if (get_bits_left(gb) < 3) {
2369             av_log(s->avctx, AV_LOG_ERROR, "Header truncated\n");
2370             return AVERROR_INVALIDDATA;
2371         }
2372         ctx->intra_dc_threshold = ff_mpeg4_dc_threshold[get_bits(gb, 3)];
2373         if (!s->progressive_sequence) {
2374             s->top_field_first = get_bits1(gb);
2375             s->alternate_scan  = get_bits1(gb);
2376         } else
2377             s->alternate_scan = 0;
2378     }
2379
2380     if (s->alternate_scan) {
2381         ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable,   ff_alternate_vertical_scan);
2382         ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,   ff_alternate_vertical_scan);
2383         ff_init_scantable(s->idsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
2384         ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2385     } else {
2386         ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable,   ff_zigzag_direct);
2387         ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,   ff_zigzag_direct);
2388         ff_init_scantable(s->idsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
2389         ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2390     }
2391
2392     if (s->pict_type == AV_PICTURE_TYPE_S &&
2393         (ctx->vol_sprite_usage == STATIC_SPRITE ||
2394          ctx->vol_sprite_usage == GMC_SPRITE)) {
2395         if (mpeg4_decode_sprite_trajectory(ctx, gb) < 0)
2396             return AVERROR_INVALIDDATA;
2397         if (ctx->sprite_brightness_change)
2398             av_log(s->avctx, AV_LOG_ERROR,
2399                    "sprite_brightness_change not supported\n");
2400         if (ctx->vol_sprite_usage == STATIC_SPRITE)
2401             av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
2402     }
2403
2404     if (ctx->shape != BIN_ONLY_SHAPE) {
2405         s->chroma_qscale = s->qscale = get_bits(gb, s->quant_precision);
2406         if (s->qscale == 0) {
2407             av_log(s->avctx, AV_LOG_ERROR,
2408                    "Error, header damaged or not MPEG4 header (qscale=0)\n");
2409             return AVERROR_INVALIDDATA;  // makes no sense to continue, as there is nothing left from the image then
2410         }
2411
2412         if (s->pict_type != AV_PICTURE_TYPE_I) {
2413             s->f_code = get_bits(gb, 3);        /* fcode_for */
2414             if (s->f_code == 0) {
2415                 av_log(s->avctx, AV_LOG_ERROR,
2416                        "Error, header damaged or not MPEG4 header (f_code=0)\n");
2417                 s->f_code = 1;
2418                 return AVERROR_INVALIDDATA;  // makes no sense to continue, as there is nothing left from the image then
2419             }
2420         } else
2421             s->f_code = 1;
2422
2423         if (s->pict_type == AV_PICTURE_TYPE_B) {
2424             s->b_code = get_bits(gb, 3);
2425             if (s->b_code == 0) {
2426                 av_log(s->avctx, AV_LOG_ERROR,
2427                        "Error, header damaged or not MPEG4 header (b_code=0)\n");
2428                 s->b_code=1;
2429                 return AVERROR_INVALIDDATA; // makes no sense to continue, as the MV decoding will break very quickly
2430             }
2431         } else
2432             s->b_code = 1;
2433
2434         if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
2435             av_log(s->avctx, AV_LOG_DEBUG,
2436                    "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 time:%"PRId64" tincr:%d\n",
2437                    s->qscale, s->f_code, s->b_code,
2438                    s->pict_type == AV_PICTURE_TYPE_I ? "I" : (s->pict_type == AV_PICTURE_TYPE_P ? "P" : (s->pict_type == AV_PICTURE_TYPE_B ? "B" : "S")),
2439                    gb->size_in_bits,s->progressive_sequence, s->alternate_scan,
2440                    s->top_field_first, s->quarter_sample ? "q" : "h",
2441                    s->data_partitioning, ctx->resync_marker,
2442                    ctx->num_sprite_warping_points, s->sprite_warping_accuracy,
2443                    1 - s->no_rounding, s->vo_type,
2444                    ctx->vol_control_parameters ? " VOLC" : " ", ctx->intra_dc_threshold,
2445                    ctx->cplx_estimation_trash_i, ctx->cplx_estimation_trash_p,
2446                    ctx->cplx_estimation_trash_b,
2447                    s->time,
2448                    time_increment
2449                   );
2450         }
2451
2452         if (!ctx->scalability) {
2453             if (ctx->shape != RECT_SHAPE && s->pict_type != AV_PICTURE_TYPE_I)
2454                 skip_bits1(gb);  // vop shape coding type
2455         } else {
2456             if (ctx->enhancement_type) {
2457                 int load_backward_shape = get_bits1(gb);
2458                 if (load_backward_shape)
2459                     av_log(s->avctx, AV_LOG_ERROR,
2460                            "load backward shape isn't supported\n");
2461             }
2462             skip_bits(gb, 2);  // ref_select_code
2463         }
2464     }
2465     /* detect buggy encoders which don't set the low_delay flag
2466      * (divx4/xvid/opendivx). Note we cannot detect divx5 without b-frames
2467      * easily (although it's buggy too) */
2468     if (s->vo_type == 0 && ctx->vol_control_parameters == 0 &&
2469         ctx->divx_version == -1 && s->picture_number == 0) {
2470         av_log(s->avctx, AV_LOG_WARNING,
2471                "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
2472         s->low_delay = 1;
2473     }
2474
2475     s->picture_number++;  // better than pic number==0 always ;)
2476
2477     // FIXME add short header support
2478     s->y_dc_scale_table = ff_mpeg4_y_dc_scale_table;
2479     s->c_dc_scale_table = ff_mpeg4_c_dc_scale_table;
2480
2481     if (s->workaround_bugs & FF_BUG_EDGE) {
2482         s->h_edge_pos = s->width;
2483         s->v_edge_pos = s->height;
2484     }
2485     return 0;
2486 }
2487
2488 /**
2489  * Decode mpeg4 headers.
2490  * @return <0 if no VOP found (or a damaged one)
2491  *         FRAME_SKIPPED if a not coded VOP is found
2492  *         0 if a VOP is found
2493  */
2494 int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2495 {
2496     MpegEncContext *s = &ctx->m;
2497     unsigned startcode, v;
2498     int ret;
2499
2500     /* search next start code */
2501     align_get_bits(gb);
2502
2503     if (s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630) {
2504         skip_bits(gb, 24);
2505         if (get_bits(gb, 8) == 0xF0)
2506             goto end;
2507     }
2508
2509     startcode = 0xff;
2510     for (;;) {
2511         if (get_bits_count(gb) >= gb->size_in_bits) {
2512             if (gb->size_in_bits == 8 &&
2513                 (ctx->divx_version >= 0 || ctx->xvid_build >= 0) || s->codec_tag == AV_RL32("QMP4")) {
2514                 av_log(s->avctx, AV_LOG_VERBOSE, "frame skip %d\n", gb->size_in_bits);
2515                 return FRAME_SKIPPED;  // divx bug
2516             } else
2517                 return -1;  // end of stream
2518         }
2519
2520         /* use the bits after the test */
2521         v = get_bits(gb, 8);
2522         startcode = ((startcode << 8) | v) & 0xffffffff;
2523
2524         if ((startcode & 0xFFFFFF00) != 0x100)
2525             continue;  // no startcode
2526
2527         if (s->avctx->debug & FF_DEBUG_STARTCODE) {
2528             av_log(s->avctx, AV_LOG_DEBUG, "startcode: %3X ", startcode);
2529             if (startcode <= 0x11F)
2530                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
2531             else if (startcode <= 0x12F)
2532                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
2533             else if (startcode <= 0x13F)
2534                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2535             else if (startcode <= 0x15F)
2536                 av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
2537             else if (startcode <= 0x1AF)
2538                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2539             else if (startcode == 0x1B0)
2540                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
2541             else if (startcode == 0x1B1)
2542                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
2543             else if (startcode == 0x1B2)
2544                 av_log(s->avctx, AV_LOG_DEBUG, "User Data");
2545             else if (startcode == 0x1B3)
2546                 av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
2547             else if (startcode == 0x1B4)
2548                 av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
2549             else if (startcode == 0x1B5)
2550                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
2551             else if (startcode == 0x1B6)
2552                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
2553             else if (startcode == 0x1B7)
2554                 av_log(s->avctx, AV_LOG_DEBUG, "slice start");
2555             else if (startcode == 0x1B8)
2556                 av_log(s->avctx, AV_LOG_DEBUG, "extension start");
2557             else if (startcode == 0x1B9)
2558                 av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
2559             else if (startcode == 0x1BA)
2560                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
2561             else if (startcode == 0x1BB)
2562                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
2563             else if (startcode == 0x1BC)
2564                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
2565             else if (startcode == 0x1BD)
2566                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
2567             else if (startcode == 0x1BE)
2568                 av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
2569             else if (startcode == 0x1BF)
2570                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
2571             else if (startcode == 0x1C0)
2572                 av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
2573             else if (startcode == 0x1C1)
2574                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
2575             else if (startcode == 0x1C2)
2576                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
2577             else if (startcode == 0x1C3)
2578                 av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
2579             else if (startcode <= 0x1C5)
2580                 av_log(s->avctx, AV_LOG_DEBUG, "reserved");
2581             else if (startcode <= 0x1FF)
2582                 av_log(s->avctx, AV_LOG_DEBUG, "System start");
2583             av_log(s->avctx, AV_LOG_DEBUG, " at %d\n", get_bits_count(gb));
2584         }
2585
2586         if (startcode >= 0x120 && startcode <= 0x12F) {
2587             if ((ret = decode_vol_header(ctx, gb)) < 0)
2588                 return ret;
2589         } else if (startcode == USER_DATA_STARTCODE) {
2590             decode_user_data(ctx, gb);
2591         } else if (startcode == GOP_STARTCODE) {
2592             mpeg4_decode_gop_header(s, gb);
2593         } else if (startcode == VOS_STARTCODE) {
2594             mpeg4_decode_profile_level(s, gb);
2595         } else if (startcode == VOP_STARTCODE) {
2596             break;
2597         }
2598
2599         align_get_bits(gb);
2600         startcode = 0xff;
2601     }
2602
2603 end:
2604     if (s->flags & CODEC_FLAG_LOW_DELAY)
2605         s->low_delay = 1;
2606     s->avctx->has_b_frames = !s->low_delay;
2607
2608     return decode_vop_header(ctx, gb);
2609 }
2610
2611 av_cold void ff_mpeg4videodec_static_init(void) {
2612     static int done = 0;
2613
2614     if (!done) {
2615         ff_init_rl(&ff_mpeg4_rl_intra, ff_mpeg4_static_rl_table_store[0]);
2616         ff_init_rl(&ff_rvlc_rl_inter, ff_mpeg4_static_rl_table_store[1]);
2617         ff_init_rl(&ff_rvlc_rl_intra, ff_mpeg4_static_rl_table_store[2]);
2618         INIT_VLC_RL(ff_mpeg4_rl_intra, 554);
2619         INIT_VLC_RL(ff_rvlc_rl_inter, 1072);
2620         INIT_VLC_RL(ff_rvlc_rl_intra, 1072);
2621         INIT_VLC_STATIC(&dc_lum, DC_VLC_BITS, 10 /* 13 */,
2622                         &ff_mpeg4_DCtab_lum[0][1], 2, 1,
2623                         &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
2624         INIT_VLC_STATIC(&dc_chrom, DC_VLC_BITS, 10 /* 13 */,
2625                         &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
2626                         &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
2627         INIT_VLC_STATIC(&sprite_trajectory, SPRITE_TRAJ_VLC_BITS, 15,
2628                         &ff_sprite_trajectory_tab[0][1], 4, 2,
2629                         &ff_sprite_trajectory_tab[0][0], 4, 2, 128);
2630         INIT_VLC_STATIC(&mb_type_b_vlc, MB_TYPE_B_VLC_BITS, 4,
2631                         &ff_mb_type_b_tab[0][1], 2, 1,
2632                         &ff_mb_type_b_tab[0][0], 2, 1, 16);
2633         done = 1;
2634     }
2635 }
2636
2637 int ff_mpeg4_frame_end(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
2638 {
2639     Mpeg4DecContext *ctx = avctx->priv_data;
2640     MpegEncContext    *s = &ctx->m;
2641
2642     /* divx 5.01+ bitstream reorder stuff */
2643     /* Since this clobbers the input buffer and hwaccel codecs still need the
2644      * data during hwaccel->end_frame we should not do this any earlier */
2645     if (s->divx_packed) {
2646         int current_pos     = s->gb.buffer == s->bitstream_buffer ? 0 : (get_bits_count(&s->gb) >> 3);
2647         int startcode_found = 0;
2648
2649         if (buf_size - current_pos > 7) {
2650
2651             int i;
2652             for (i = current_pos; i < buf_size - 4; i++)
2653
2654                 if (buf[i]     == 0 &&
2655                     buf[i + 1] == 0 &&
2656                     buf[i + 2] == 1 &&
2657                     buf[i + 3] == 0xB6) {
2658                     startcode_found = !(buf[i + 4] & 0x40);
2659                     break;
2660                 }
2661         }
2662
2663         if (startcode_found) {
2664             if (!ctx->showed_packed_warning) {
2665                 av_log(s->avctx, AV_LOG_INFO, "Video uses a non-standard and "
2666                        "wasteful way to store B-frames ('packed B-frames'). "
2667                        "Consider using the mpeg4_unpack_bframes bitstream filter to fix it.\n");
2668                 ctx->showed_packed_warning = 1;
2669             }
2670             av_fast_padded_malloc(&s->bitstream_buffer,
2671                            &s->allocated_bitstream_buffer_size,
2672                            buf_size - current_pos);
2673             if (!s->bitstream_buffer)
2674                 return AVERROR(ENOMEM);
2675             memcpy(s->bitstream_buffer, buf + current_pos,
2676                    buf_size - current_pos);
2677             s->bitstream_buffer_size = buf_size - current_pos;
2678         }
2679     }
2680
2681     return 0;
2682 }
2683
2684 static int mpeg4_update_thread_context(AVCodecContext *dst,
2685                                        const AVCodecContext *src)
2686 {
2687     Mpeg4DecContext *s = dst->priv_data;
2688     const Mpeg4DecContext *s1 = src->priv_data;
2689     int init = s->m.context_initialized;
2690
2691     int ret = ff_mpeg_update_thread_context(dst, src);
2692
2693     if (ret < 0)
2694         return ret;
2695
2696     memcpy(((uint8_t*)s) + sizeof(MpegEncContext), ((uint8_t*)s1) + sizeof(MpegEncContext), sizeof(Mpeg4DecContext) - sizeof(MpegEncContext));
2697
2698     if (CONFIG_MPEG4_DECODER && !init && s1->xvid_build >= 0)
2699         ff_xvid_idct_init(&s->m.idsp, dst);
2700
2701     return 0;
2702 }
2703
2704 static av_cold int decode_init(AVCodecContext *avctx)
2705 {
2706     Mpeg4DecContext *ctx = avctx->priv_data;
2707     MpegEncContext *s = &ctx->m;
2708     int ret;
2709
2710     ctx->divx_version =
2711     ctx->divx_build   =
2712     ctx->xvid_build   =
2713     ctx->lavc_build   = -1;
2714
2715     if ((ret = ff_h263_decode_init(avctx)) < 0)
2716         return ret;
2717
2718     ff_mpeg4videodec_static_init();
2719
2720     s->h263_pred = 1;
2721     s->low_delay = 0; /* default, might be overridden in the vol header during header parsing */
2722     s->decode_mb = mpeg4_decode_mb;
2723     ctx->time_increment_bits = 4; /* default value for broken headers */
2724
2725     avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
2726     avctx->internal->allocate_progress = 1;
2727
2728     return 0;
2729 }
2730
2731 static const AVProfile mpeg4_video_profiles[] = {
2732     { FF_PROFILE_MPEG4_SIMPLE,                    "Simple Profile" },
2733     { FF_PROFILE_MPEG4_SIMPLE_SCALABLE,           "Simple Scalable Profile" },
2734     { FF_PROFILE_MPEG4_CORE,                      "Core Profile" },
2735     { FF_PROFILE_MPEG4_MAIN,                      "Main Profile" },
2736     { FF_PROFILE_MPEG4_N_BIT,                     "N-bit Profile" },
2737     { FF_PROFILE_MPEG4_SCALABLE_TEXTURE,          "Scalable Texture Profile" },
2738     { FF_PROFILE_MPEG4_SIMPLE_FACE_ANIMATION,     "Simple Face Animation Profile" },
2739     { FF_PROFILE_MPEG4_BASIC_ANIMATED_TEXTURE,    "Basic Animated Texture Profile" },
2740     { FF_PROFILE_MPEG4_HYBRID,                    "Hybrid Profile" },
2741     { FF_PROFILE_MPEG4_ADVANCED_REAL_TIME,        "Advanced Real Time Simple Profile" },
2742     { FF_PROFILE_MPEG4_CORE_SCALABLE,             "Code Scalable Profile" },
2743     { FF_PROFILE_MPEG4_ADVANCED_CODING,           "Advanced Coding Profile" },
2744     { FF_PROFILE_MPEG4_ADVANCED_CORE,             "Advanced Core Profile" },
2745     { FF_PROFILE_MPEG4_ADVANCED_SCALABLE_TEXTURE, "Advanced Scalable Texture Profile" },
2746     { FF_PROFILE_MPEG4_SIMPLE_STUDIO,             "Simple Studio Profile" },
2747     { FF_PROFILE_MPEG4_ADVANCED_SIMPLE,           "Advanced Simple Profile" },
2748     { FF_PROFILE_UNKNOWN },
2749 };
2750
2751 static const AVOption mpeg4_options[] = {
2752     {"quarter_sample", "1/4 subpel MC", offsetof(MpegEncContext, quarter_sample), FF_OPT_TYPE_INT, {.i64 = 0}, 0, 1, 0},
2753     {"divx_packed", "divx style packed b frames", offsetof(MpegEncContext, divx_packed), FF_OPT_TYPE_INT, {.i64 = 0}, 0, 1, 0},
2754     {NULL}
2755 };
2756
2757 static const AVClass mpeg4_class = {
2758     "MPEG4 Video Decoder",
2759     av_default_item_name,
2760     mpeg4_options,
2761     LIBAVUTIL_VERSION_INT,
2762 };
2763
2764 AVCodec ff_mpeg4_decoder = {
2765     .name                  = "mpeg4",
2766     .long_name             = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
2767     .type                  = AVMEDIA_TYPE_VIDEO,
2768     .id                    = AV_CODEC_ID_MPEG4,
2769     .priv_data_size        = sizeof(Mpeg4DecContext),
2770     .init                  = decode_init,
2771     .close                 = ff_h263_decode_end,
2772     .decode                = ff_h263_decode_frame,
2773     .capabilities          = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
2774                              CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
2775                              CODEC_CAP_FRAME_THREADS,
2776     .flush                 = ff_mpeg_flush,
2777     .max_lowres            = 3,
2778     .pix_fmts              = ff_h263_hwaccel_pixfmt_list_420,
2779     .profiles              = NULL_IF_CONFIG_SMALL(mpeg4_video_profiles),
2780     .update_thread_context = ONLY_IF_THREADS_ENABLED(mpeg4_update_thread_context),
2781     .priv_class = &mpeg4_class,
2782 };
2783
2784
2785 #if CONFIG_MPEG4_VDPAU_DECODER
2786 static const AVClass mpeg4_vdpau_class = {
2787     "MPEG4 Video VDPAU Decoder",
2788     av_default_item_name,
2789     mpeg4_options,
2790     LIBAVUTIL_VERSION_INT,
2791 };
2792
2793 AVCodec ff_mpeg4_vdpau_decoder = {
2794     .name           = "mpeg4_vdpau",
2795     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),
2796     .type           = AVMEDIA_TYPE_VIDEO,
2797     .id             = AV_CODEC_ID_MPEG4,
2798     .priv_data_size = sizeof(Mpeg4DecContext),
2799     .init           = decode_init,
2800     .close          = ff_h263_decode_end,
2801     .decode         = ff_h263_decode_frame,
2802     .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
2803                       CODEC_CAP_HWACCEL_VDPAU,
2804     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_VDPAU_MPEG4,
2805                                                   AV_PIX_FMT_NONE },
2806     .priv_class     = &mpeg4_vdpau_class,
2807 };
2808 #endif