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 "mpegvideodata.h"
  32 #include "mpeg4video.h"
  33 #include "h263.h"
  34 #include "thread.h"
  35 #include "xvididct.h"
  36
  37 /* The defines below define the number of bits that are read at once for
  38  * reading vlc values. Changing these may improve speed and data cache needs
  39  * be aware though that decreasing them may need the number of stages that is
  40  * passed to get_vlc* to be increased. */
  41 #define SPRITE_TRAJ_VLC_BITS 6
  42 #define DC_VLC_BITS 9
  43 #define MB_TYPE_B_VLC_BITS 4
  44
  45 static VLC dc_lum, dc_chrom;
  46 static VLC sprite_trajectory;
  47 static VLC mb_type_b_vlc;
  48
  49 static const int mb_type_b_map[4] = {
  50     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
  51     MB_TYPE_L0L1    | MB_TYPE_16x16,
  52     MB_TYPE_L1      | MB_TYPE_16x16,
  53     MB_TYPE_L0      | MB_TYPE_16x16,
  54 };
  55
  56 /**
  57  * Predict the ac.
  58  * @param n block index (0-3 are luma, 4-5 are chroma)
  59  * @param dir the ac prediction direction
  60  */
  61 void ff_mpeg4_pred_ac(MpegEncContext *s, int16_t *block, int n, int dir)
  62 {
  63     int i;
  64     int16_t *ac_val, *ac_val1;
  65     int8_t *const qscale_table = s->current_picture.qscale_table;
  66
  67     /* find prediction */
  68     ac_val  = s->ac_val[0][0] + s->block_index[n] * 16;
  69     ac_val1 = ac_val;
  70     if (s->ac_pred) {
  71         if (dir == 0) {
  72             const int xy = s->mb_x - 1 + s->mb_y * s->mb_stride;
  73             /* left prediction */
  74             ac_val -= 16;
  75
  76             if (s->mb_x == 0 || s->qscale == qscale_table[xy] ||
  77                 n == 1 || n == 3) {
  78                 /* same qscale */
  79                 for (i = 1; i < 8; i++)
  80                     block[s->idsp.idct_permutation[i << 3]] += ac_val[i];
  81             } else {
  82                 /* different qscale, we must rescale */
  83                 for (i = 1; i < 8; i++)
  84                     block[s->idsp.idct_permutation[i << 3]] += ROUNDED_DIV(ac_val[i] * qscale_table[xy], s->qscale);
  85             }
  86         } else {
  87             const int xy = s->mb_x + s->mb_y * s->mb_stride - s->mb_stride;
  88             /* top prediction */
  89             ac_val -= 16 * s->block_wrap[n];
  90
  91             if (s->mb_y == 0 || s->qscale == qscale_table[xy] ||
  92                 n == 2 || n == 3) {
  93                 /* same qscale */
  94                 for (i = 1; i < 8; i++)
  95                     block[s->idsp.idct_permutation[i]] += ac_val[i + 8];
  96             } else {
  97                 /* different qscale, we must rescale */
  98                 for (i = 1; i < 8; i++)
  99                     block[s->idsp.idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8] * qscale_table[xy], s->qscale);
 100             }
 101         }
 102     }
 103     /* left copy */
 104     for (i = 1; i < 8; i++)
 105         ac_val1[i] = block[s->idsp.idct_permutation[i << 3]];
 106
 107     /* top copy */
 108     for (i = 1; i < 8; i++)
 109         ac_val1[8 + i] = block[s->idsp.idct_permutation[i]];
 110 }
 111
 112 /**
 113  * check if the next stuff is a resync marker or the end.
 114  * @return 0 if not
 115  */
 116 static inline int mpeg4_is_resync(Mpeg4DecContext *ctx)
 117 {
 118     MpegEncContext *s = &ctx->m;
 119     int bits_count = get_bits_count(&s->gb);
 120     int v          = show_bits(&s->gb, 16);
 121
 122     if (s->workaround_bugs & FF_BUG_NO_PADDING && !ctx->resync_marker)
 123         return 0;
 124
 125     while (v <= 0xFF) {
 126         if (s->pict_type == AV_PICTURE_TYPE_B ||
 127             (v >> (8 - s->pict_type) != 1) || s->partitioned_frame)
 128             break;
 129         skip_bits(&s->gb, 8 + s->pict_type);
 130         bits_count += 8 + s->pict_type;
 131         v = show_bits(&s->gb, 16);
 132     }
 133
 134     if (bits_count + 8 >= s->gb.size_in_bits) {
 135         v >>= 8;
 136         v  |= 0x7F >> (7 - (bits_count & 7));
 137
 138         if (v == 0x7F)
 139             return s->mb_num;
 140     } else {
 141         if (v == ff_mpeg4_resync_prefix[bits_count & 7]) {
 142             int len, mb_num;
 143             int mb_num_bits = av_log2(s->mb_num - 1) + 1;
 144             GetBitContext gb = s->gb;
 145
 146             skip_bits(&s->gb, 1);
 147             align_get_bits(&s->gb);
 148
 149             for (len = 0; len < 32; len++)
 150                 if (get_bits1(&s->gb))
 151                     break;
 152
 153             mb_num = get_bits(&s->gb, mb_num_bits);
 154             if (!mb_num || mb_num > s->mb_num || get_bits_count(&s->gb)+6 > s->gb.size_in_bits)
 155                 mb_num= -1;
 156
 157             s->gb = gb;
 158
 159             if (len >= ff_mpeg4_get_video_packet_prefix_length(s))
 160                 return mb_num;
 161         }
 162     }
 163     return 0;
 164 }
 165
 166 static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *gb)
 167 {
 168     MpegEncContext *s = &ctx->m;
 169     int a     = 2 << s->sprite_warping_accuracy;
 170     int rho   = 3  - s->sprite_warping_accuracy;
 171     int r     = 16 / a;
 172     int alpha = 0;
 173     int beta  = 0;
 174     int w     = s->width;
 175     int h     = s->height;
 176     int min_ab, i, w2, h2, w3, h3;
 177     int sprite_ref[4][2];
 178     int virtual_ref[2][2];
 179
 180     // only true for rectangle shapes
 181     const int vop_ref[4][2] = { { 0, 0 },         { s->width, 0 },
 182                                 { 0, s->height }, { s->width, s->height } };
 183     int d[4][2]             = { { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } };
 184
 185     if (w <= 0 || h <= 0)
 186         return AVERROR_INVALIDDATA;
 187
 188     for (i = 0; i < ctx->num_sprite_warping_points; i++) {
 189         int length;
 190         int x = 0, y = 0;
 191
 192         length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 193         if (length > 0)
 194             x = get_xbits(gb, length);
 195
 196         if (!(ctx->divx_version == 500 && ctx->divx_build == 413))
 197             check_marker(gb, "before sprite_trajectory");
 198
 199         length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 200         if (length > 0)
 201             y = get_xbits(gb, length);
 202
 203         check_marker(gb, "after sprite_trajectory");
 204         ctx->sprite_traj[i][0] = d[i][0] = x;
 205         ctx->sprite_traj[i][1] = d[i][1] = y;
 206     }
 207     for (; i < 4; i++)
 208         ctx->sprite_traj[i][0] = ctx->sprite_traj[i][1] = 0;
 209
 210     while ((1 << alpha) < w)
 211         alpha++;
 212     while ((1 << beta) < h)
 213         beta++;  /* typo in the mpeg4 std for the definition of w' and h' */
 214     w2 = 1 << alpha;
 215     h2 = 1 << beta;
 216
 217     // Note, the 4th point isn't used for GMC
 218     if (ctx->divx_version == 500 && ctx->divx_build == 413) {
 219         sprite_ref[0][0] = a * vop_ref[0][0] + d[0][0];
 220         sprite_ref[0][1] = a * vop_ref[0][1] + d[0][1];
 221         sprite_ref[1][0] = a * vop_ref[1][0] + d[0][0] + d[1][0];
 222         sprite_ref[1][1] = a * vop_ref[1][1] + d[0][1] + d[1][1];
 223         sprite_ref[2][0] = a * vop_ref[2][0] + d[0][0] + d[2][0];
 224         sprite_ref[2][1] = a * vop_ref[2][1] + d[0][1] + d[2][1];
 225     } else {
 226         sprite_ref[0][0] = (a >> 1) * (2 * vop_ref[0][0] + d[0][0]);
 227         sprite_ref[0][1] = (a >> 1) * (2 * vop_ref[0][1] + d[0][1]);
 228         sprite_ref[1][0] = (a >> 1) * (2 * vop_ref[1][0] + d[0][0] + d[1][0]);
 229         sprite_ref[1][1] = (a >> 1) * (2 * vop_ref[1][1] + d[0][1] + d[1][1]);
 230         sprite_ref[2][0] = (a >> 1) * (2 * vop_ref[2][0] + d[0][0] + d[2][0]);
 231         sprite_ref[2][1] = (a >> 1) * (2 * vop_ref[2][1] + d[0][1] + d[2][1]);
 232     }
 233     /* sprite_ref[3][0] = (a >> 1) * (2 * vop_ref[3][0] + d[0][0] + d[1][0] + d[2][0] + d[3][0]);
 234      * sprite_ref[3][1] = (a >> 1) * (2 * vop_ref[3][1] + d[0][1] + d[1][1] + d[2][1] + d[3][1]); */
 235
 236     /* this is mostly identical to the mpeg4 std (and is totally unreadable
 237      * because of that...). Perhaps it should be reordered to be more readable.
 238      * The idea behind this virtual_ref mess is to be able to use shifts later
 239      * per pixel instead of divides so the distance between points is converted
 240      * from w&h based to w2&h2 based which are of the 2^x form. */
 241     virtual_ref[0][0] = 16 * (vop_ref[0][0] + w2) +
 242                          ROUNDED_DIV(((w - w2) *
 243                                       (r * sprite_ref[0][0] - 16 * vop_ref[0][0]) +
 244                                       w2 * (r * sprite_ref[1][0] - 16 * vop_ref[1][0])), w);
 245     virtual_ref[0][1] = 16 * vop_ref[0][1] +
 246                         ROUNDED_DIV(((w - w2) *
 247                                      (r * sprite_ref[0][1] - 16 * vop_ref[0][1]) +
 248                                      w2 * (r * sprite_ref[1][1] - 16 * vop_ref[1][1])), w);
 249     virtual_ref[1][0] = 16 * vop_ref[0][0] +
 250                         ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][0] - 16 * vop_ref[0][0]) +
 251                                      h2 * (r * sprite_ref[2][0] - 16 * vop_ref[2][0])), h);
 252     virtual_ref[1][1] = 16 * (vop_ref[0][1] + h2) +
 253                         ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][1] - 16 * vop_ref[0][1]) +
 254                                      h2 * (r * sprite_ref[2][1] - 16 * vop_ref[2][1])), h);
 255
 256     switch (ctx->num_sprite_warping_points) {
 257     case 0:
 258         s->sprite_offset[0][0] =
 259         s->sprite_offset[0][1] =
 260         s->sprite_offset[1][0] =
 261         s->sprite_offset[1][1] = 0;
 262         s->sprite_delta[0][0]  = a;
 263         s->sprite_delta[0][1]  =
 264         s->sprite_delta[1][0]  = 0;
 265         s->sprite_delta[1][1]  = a;
 266         ctx->sprite_shift[0]   =
 267         ctx->sprite_shift[1]   = 0;
 268         break;
 269     case 1:     // GMC only
 270         s->sprite_offset[0][0] = sprite_ref[0][0] - a * vop_ref[0][0];
 271         s->sprite_offset[0][1] = sprite_ref[0][1] - a * vop_ref[0][1];
 272         s->sprite_offset[1][0] = ((sprite_ref[0][0] >> 1) | (sprite_ref[0][0] & 1)) -
 273                                  a * (vop_ref[0][0] / 2);
 274         s->sprite_offset[1][1] = ((sprite_ref[0][1] >> 1) | (sprite_ref[0][1] & 1)) -
 275                                  a * (vop_ref[0][1] / 2);
 276         s->sprite_delta[0][0]  = a;
 277         s->sprite_delta[0][1]  =
 278         s->sprite_delta[1][0]  = 0;
 279         s->sprite_delta[1][1]  = a;
 280         ctx->sprite_shift[0]   =
 281         ctx->sprite_shift[1]   = 0;
 282         break;
 283     case 2:
 284         s->sprite_offset[0][0] = (sprite_ref[0][0] << (alpha + rho)) +
 285                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 286                                  (-vop_ref[0][0]) +
 287                                  (r * sprite_ref[0][1] - virtual_ref[0][1]) *
 288                                  (-vop_ref[0][1]) + (1 << (alpha + rho - 1));
 289         s->sprite_offset[0][1] = (sprite_ref[0][1] << (alpha + rho)) +
 290                                  (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 291                                  (-vop_ref[0][0]) +
 292                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 293                                  (-vop_ref[0][1]) + (1 << (alpha + rho - 1));
 294         s->sprite_offset[1][0] = ((-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 295                                   (-2 * vop_ref[0][0] + 1) +
 296                                   (r * sprite_ref[0][1] - virtual_ref[0][1]) *
 297                                   (-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
 298                                   sprite_ref[0][0] - 16 * w2 + (1 << (alpha + rho + 1)));
 299         s->sprite_offset[1][1] = ((-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 300                                   (-2 * vop_ref[0][0] + 1) +
 301                                   (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 302                                   (-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
 303                                   sprite_ref[0][1] - 16 * w2 + (1 << (alpha + rho + 1)));
 304         s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
 305         s->sprite_delta[0][1] = (+r * sprite_ref[0][1] - virtual_ref[0][1]);
 306         s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]);
 307         s->sprite_delta[1][1] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
 308
 309         ctx->sprite_shift[0]  = alpha + rho;
 310         ctx->sprite_shift[1]  = alpha + rho + 2;
 311         break;
 312     case 3:
 313         min_ab = FFMIN(alpha, beta);
 314         w3     = w2 >> min_ab;
 315         h3     = h2 >> min_ab;
 316         s->sprite_offset[0][0] = (sprite_ref[0][0] << (alpha + beta + rho - min_ab)) +
 317                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 318                                  h3 * (-vop_ref[0][0]) +
 319                                  (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
 320                                  w3 * (-vop_ref[0][1]) +
 321                                  (1 << (alpha + beta + rho - min_ab - 1));
 322         s->sprite_offset[0][1] = (sprite_ref[0][1] << (alpha + beta + rho - min_ab)) +
 323                                  (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 324                                  h3 * (-vop_ref[0][0]) +
 325                                  (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
 326                                  w3 * (-vop_ref[0][1]) +
 327                                  (1 << (alpha + beta + rho - min_ab - 1));
 328         s->sprite_offset[1][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 329                                  h3 * (-2 * vop_ref[0][0] + 1) +
 330                                  (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
 331                                  w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
 332                                  r * sprite_ref[0][0] - 16 * w2 * h3 +
 333                                  (1 << (alpha + beta + rho - min_ab + 1));
 334         s->sprite_offset[1][1] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 335                                  h3 * (-2 * vop_ref[0][0] + 1) +
 336                                  (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
 337                                  w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
 338                                  r * sprite_ref[0][1] - 16 * w2 * h3 +
 339                                  (1 << (alpha + beta + rho - min_ab + 1));
 340         s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3;
 341         s->sprite_delta[0][1] = (-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3;
 342         s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3;
 343         s->sprite_delta[1][1] = (-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3;
 344
 345         ctx->sprite_shift[0]  = alpha + beta + rho - min_ab;
 346         ctx->sprite_shift[1]  = alpha + beta + rho - min_ab + 2;
 347         break;
 348     }
 349     /* try to simplify the situation */
 350     if (s->sprite_delta[0][0] == a << ctx->sprite_shift[0] &&
 351         s->sprite_delta[0][1] == 0 &&
 352         s->sprite_delta[1][0] == 0 &&
 353         s->sprite_delta[1][1] == a << ctx->sprite_shift[0]) {
 354         s->sprite_offset[0][0] >>= ctx->sprite_shift[0];
 355         s->sprite_offset[0][1] >>= ctx->sprite_shift[0];
 356         s->sprite_offset[1][0] >>= ctx->sprite_shift[1];
 357         s->sprite_offset[1][1] >>= ctx->sprite_shift[1];
 358         s->sprite_delta[0][0] = a;
 359         s->sprite_delta[0][1] = 0;
 360         s->sprite_delta[1][0] = 0;
 361         s->sprite_delta[1][1] = a;
 362         ctx->sprite_shift[0] = 0;
 363         ctx->sprite_shift[1] = 0;
 364         s->real_sprite_warping_points = 1;
 365     } else {
 366         int shift_y = 16 - ctx->sprite_shift[0];
 367         int shift_c = 16 - ctx->sprite_shift[1];
 368         for (i = 0; i < 2; i++) {
 369             s->sprite_offset[0][i] <<= shift_y;
 370             s->sprite_offset[1][i] <<= shift_c;
 371             s->sprite_delta[0][i]  <<= shift_y;
 372             s->sprite_delta[1][i]  <<= shift_y;
 373             ctx->sprite_shift[i]     = 16;
 374         }
 375         s->real_sprite_warping_points = ctx->num_sprite_warping_points;
 376     }
 377
 378     return 0;
 379 }
 380
 381 static int decode_new_pred(Mpeg4DecContext *ctx, GetBitContext *gb) {
 382     int len = FFMIN(ctx->time_increment_bits + 3, 15);
 383
 384     get_bits(gb, len);
 385     if (get_bits1(gb))
 386         get_bits(gb, len);
 387     check_marker(gb, "after new_pred");
 388
 389     return 0;
 390 }
 391
 392 /**
 393  * Decode the next video packet.
 394  * @return <0 if something went wrong
 395  */
 396 int ff_mpeg4_decode_video_packet_header(Mpeg4DecContext *ctx)
 397 {
 398     MpegEncContext *s = &ctx->m;
 399
 400     int mb_num_bits      = av_log2(s->mb_num - 1) + 1;
 401     int header_extension = 0, mb_num, len;
 402
 403     /* is there enough space left for a video packet + header */
 404     if (get_bits_count(&s->gb) > s->gb.size_in_bits - 20)
 405         return -1;
 406
 407     for (len = 0; len < 32; len++)
 408         if (get_bits1(&s->gb))
 409             break;
 410
 411     if (len != ff_mpeg4_get_video_packet_prefix_length(s)) {
 412         av_log(s->avctx, AV_LOG_ERROR, "marker does not match f_code\n");
 413         return -1;
 414     }
 415
 416     if (ctx->shape != RECT_SHAPE) {
 417         header_extension = get_bits1(&s->gb);
 418         // FIXME more stuff here
 419     }
 420
 421     mb_num = get_bits(&s->gb, mb_num_bits);
 422     if (mb_num >= s->mb_num) {
 423         av_log(s->avctx, AV_LOG_ERROR,
 424                "illegal mb_num in video packet (%d %d) \n", mb_num, s->mb_num);
 425         return -1;
 426     }
 427
 428     s->mb_x = mb_num % s->mb_width;
 429     s->mb_y = mb_num / s->mb_width;
 430
 431     if (ctx->shape != BIN_ONLY_SHAPE) {
 432         int qscale = get_bits(&s->gb, s->quant_precision);
 433         if (qscale)
 434             s->chroma_qscale = s->qscale = qscale;
 435     }
 436
 437     if (ctx->shape == RECT_SHAPE)
 438         header_extension = get_bits1(&s->gb);
 439
 440     if (header_extension) {
 441         int time_incr = 0;
 442
 443         while (get_bits1(&s->gb) != 0)
 444             time_incr++;
 445
 446         check_marker(&s->gb, "before time_increment in video packed header");
 447         skip_bits(&s->gb, ctx->time_increment_bits);      /* time_increment */
 448         check_marker(&s->gb, "before vop_coding_type in video packed header");
 449
 450         skip_bits(&s->gb, 2); /* vop coding type */
 451         // FIXME not rect stuff here
 452
 453         if (ctx->shape != BIN_ONLY_SHAPE) {
 454             skip_bits(&s->gb, 3); /* intra dc vlc threshold */
 455             // FIXME don't just ignore everything
 456             if (s->pict_type == AV_PICTURE_TYPE_S &&
 457                 ctx->vol_sprite_usage == GMC_SPRITE) {
 458                 if (mpeg4_decode_sprite_trajectory(ctx, &s->gb) < 0)
 459                     return AVERROR_INVALIDDATA;
 460                 av_log(s->avctx, AV_LOG_ERROR, "untested\n");
 461             }
 462
 463             // FIXME reduced res stuff here
 464
 465             if (s->pict_type != AV_PICTURE_TYPE_I) {
 466                 int f_code = get_bits(&s->gb, 3);       /* fcode_for */
 467                 if (f_code == 0)
 468                     av_log(s->avctx, AV_LOG_ERROR,
 469                            "Error, video packet header damaged (f_code=0)\n");
 470             }
 471             if (s->pict_type == AV_PICTURE_TYPE_B) {
 472                 int b_code = get_bits(&s->gb, 3);
 473                 if (b_code == 0)
 474                     av_log(s->avctx, AV_LOG_ERROR,
 475                            "Error, video packet header damaged (b_code=0)\n");
 476             }
 477         }
 478     }
 479     if (ctx->new_pred)
 480         decode_new_pred(ctx, &s->gb);
 481
 482     return 0;
 483 }
 484
 485 /**
 486  * Get the average motion vector for a GMC MB.
 487  * @param n either 0 for the x component or 1 for y
 488  * @return the average MV for a GMC MB
 489  */
 490 static inline int get_amv(Mpeg4DecContext *ctx, int n)
 491 {
 492     MpegEncContext *s = &ctx->m;
 493     int x, y, mb_v, sum, dx, dy, shift;
 494     int len     = 1 << (s->f_code + 4);
 495     const int a = s->sprite_warping_accuracy;
 496
 497     if (s->workaround_bugs & FF_BUG_AMV)
 498         len >>= s->quarter_sample;
 499
 500     if (s->real_sprite_warping_points == 1) {
 501         if (ctx->divx_version == 500 && ctx->divx_build == 413)
 502             sum = s->sprite_offset[0][n] / (1 << (a - s->quarter_sample));
 503         else
 504             sum = RSHIFT(s->sprite_offset[0][n] << s->quarter_sample, a);
 505     } else {
 506         dx    = s->sprite_delta[n][0];
 507         dy    = s->sprite_delta[n][1];
 508         shift = ctx->sprite_shift[0];
 509         if (n)
 510             dy -= 1 << (shift + a + 1);
 511         else
 512             dx -= 1 << (shift + a + 1);
 513         mb_v = s->sprite_offset[0][n] + dx * s->mb_x * 16 + dy * s->mb_y * 16;
 514
 515         sum = 0;
 516         for (y = 0; y < 16; y++) {
 517             int v;
 518
 519             v = mb_v + dy * y;
 520             // FIXME optimize
 521             for (x = 0; x < 16; x++) {
 522                 sum += v >> shift;
 523                 v   += dx;
 524             }
 525         }
 526         sum = RSHIFT(sum, a + 8 - s->quarter_sample);
 527     }
 528
 529     if (sum < -len)
 530         sum = -len;
 531     else if (sum >= len)
 532         sum = len - 1;
 533
 534     return sum;
 535 }
 536
 537 /**
 538  * Decode the dc value.
 539  * @param n block index (0-3 are luma, 4-5 are chroma)
 540  * @param dir_ptr the prediction direction will be stored here
 541  * @return the quantized dc
 542  */
 543 static inline int mpeg4_decode_dc(MpegEncContext *s, int n, int *dir_ptr)
 544 {
 545     int level, code;
 546
 547     if (n < 4)
 548         code = get_vlc2(&s->gb, dc_lum.table, DC_VLC_BITS, 1);
 549     else
 550         code = get_vlc2(&s->gb, dc_chrom.table, DC_VLC_BITS, 1);
 551
 552     if (code < 0 || code > 9 /* && s->nbit < 9 */) {
 553         av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
 554         return -1;
 555     }
 556
 557     if (code == 0) {
 558         level = 0;
 559     } else {
 560         if (IS_3IV1) {
 561             if (code == 1)
 562                 level = 2 * get_bits1(&s->gb) - 1;
 563             else {
 564                 if (get_bits1(&s->gb))
 565                     level = get_bits(&s->gb, code - 1) + (1 << (code - 1));
 566                 else
 567                     level = -get_bits(&s->gb, code - 1) - (1 << (code - 1));
 568             }
 569         } else {
 570             level = get_xbits(&s->gb, code);
 571         }
 572
 573         if (code > 8) {
 574             if (get_bits1(&s->gb) == 0) { /* marker */
 575                 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT)) {
 576                     av_log(s->avctx, AV_LOG_ERROR, "dc marker bit missing\n");
 577                     return -1;
 578                 }
 579             }
 580         }
 581     }
 582
 583     return ff_mpeg4_pred_dc(s, n, level, dir_ptr, 0);
 584 }
 585
 586 /**
 587  * Decode first partition.
 588  * @return number of MBs decoded or <0 if an error occurred
 589  */
 590 static int mpeg4_decode_partition_a(Mpeg4DecContext *ctx)
 591 {
 592     MpegEncContext *s = &ctx->m;
 593     int mb_num = 0;
 594     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 595
 596     /* decode first partition */
 597     s->first_slice_line = 1;
 598     for (; s->mb_y < s->mb_height; s->mb_y++) {
 599         ff_init_block_index(s);
 600         for (; s->mb_x < s->mb_width; s->mb_x++) {
 601             const int xy = s->mb_x + s->mb_y * s->mb_stride;
 602             int cbpc;
 603             int dir = 0;
 604
 605             mb_num++;
 606             ff_update_block_index(s);
 607             if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
 608                 s->first_slice_line = 0;
 609
 610             if (s->pict_type == AV_PICTURE_TYPE_I) {
 611                 int i;
 612
 613                 do {
 614                     if (show_bits_long(&s->gb, 19) == DC_MARKER)
 615                         return mb_num - 1;
 616
 617                     cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 618                     if (cbpc < 0) {
 619                         av_log(s->avctx, AV_LOG_ERROR,
 620                                "mcbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 621                         return -1;
 622                     }
 623                 } while (cbpc == 8);
 624
 625                 s->cbp_table[xy]               = cbpc & 3;
 626                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 627                 s->mb_intra                    = 1;
 628
 629                 if (cbpc & 4)
 630                     ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 631
 632                 s->current_picture.qscale_table[xy] = s->qscale;
 633
 634                 s->mbintra_table[xy] = 1;
 635                 for (i = 0; i < 6; i++) {
 636                     int dc_pred_dir;
 637                     int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
 638                     if (dc < 0) {
 639                         av_log(s->avctx, AV_LOG_ERROR,
 640                                "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 641                         return -1;
 642                     }
 643                     dir <<= 1;
 644                     if (dc_pred_dir)
 645                         dir |= 1;
 646                 }
 647                 s->pred_dir_table[xy] = dir;
 648             } else { /* P/S_TYPE */
 649                 int mx, my, pred_x, pred_y, bits;
 650                 int16_t *const mot_val = s->current_picture.motion_val[0][s->block_index[0]];
 651                 const int stride       = s->b8_stride * 2;
 652
 653 try_again:
 654                 bits = show_bits(&s->gb, 17);
 655                 if (bits == MOTION_MARKER)
 656                     return mb_num - 1;
 657
 658                 skip_bits1(&s->gb);
 659                 if (bits & 0x10000) {
 660                     /* skip mb */
 661                     if (s->pict_type == AV_PICTURE_TYPE_S &&
 662                         ctx->vol_sprite_usage == GMC_SPRITE) {
 663                         s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
 664                                                          MB_TYPE_16x16 |
 665                                                          MB_TYPE_GMC   |
 666                                                          MB_TYPE_L0;
 667                         mx = get_amv(ctx, 0);
 668                         my = get_amv(ctx, 1);
 669                     } else {
 670                         s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
 671                                                          MB_TYPE_16x16 |
 672                                                          MB_TYPE_L0;
 673                         mx = my = 0;
 674                     }
 675                     mot_val[0]          =
 676                     mot_val[2]          =
 677                     mot_val[0 + stride] =
 678                     mot_val[2 + stride] = mx;
 679                     mot_val[1]          =
 680                     mot_val[3]          =
 681                     mot_val[1 + stride] =
 682                     mot_val[3 + stride] = my;
 683
 684                     if (s->mbintra_table[xy])
 685                         ff_clean_intra_table_entries(s);
 686                     continue;
 687                 }
 688
 689                 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 690                 if (cbpc < 0) {
 691                     av_log(s->avctx, AV_LOG_ERROR,
 692                            "mcbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 693                     return -1;
 694                 }
 695                 if (cbpc == 20)
 696                     goto try_again;
 697
 698                 s->cbp_table[xy] = cbpc & (8 + 3);  // 8 is dquant
 699
 700                 s->mb_intra = ((cbpc & 4) != 0);
 701
 702                 if (s->mb_intra) {
 703                     s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 704                     s->mbintra_table[xy] = 1;
 705                     mot_val[0]          =
 706                     mot_val[2]          =
 707                     mot_val[0 + stride] =
 708                     mot_val[2 + stride] = 0;
 709                     mot_val[1]          =
 710                     mot_val[3]          =
 711                     mot_val[1 + stride] =
 712                     mot_val[3 + stride] = 0;
 713                 } else {
 714                     if (s->mbintra_table[xy])
 715                         ff_clean_intra_table_entries(s);
 716
 717                     if (s->pict_type == AV_PICTURE_TYPE_S &&
 718                         ctx->vol_sprite_usage == GMC_SPRITE &&
 719                         (cbpc & 16) == 0)
 720                         s->mcsel = get_bits1(&s->gb);
 721                     else
 722                         s->mcsel = 0;
 723
 724                     if ((cbpc & 16) == 0) {
 725                         /* 16x16 motion prediction */
 726
 727                         ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 728                         if (!s->mcsel) {
 729                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
 730                             if (mx >= 0xffff)
 731                                 return -1;
 732
 733                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
 734                             if (my >= 0xffff)
 735                                 return -1;
 736                             s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
 737                                                              MB_TYPE_L0;
 738                         } else {
 739                             mx = get_amv(ctx, 0);
 740                             my = get_amv(ctx, 1);
 741                             s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
 742                                                              MB_TYPE_GMC   |
 743                                                              MB_TYPE_L0;
 744                         }
 745
 746                         mot_val[0]          =
 747                         mot_val[2]          =
 748                         mot_val[0 + stride] =
 749                         mot_val[2 + stride] = mx;
 750                         mot_val[1]          =
 751                         mot_val[3]          =
 752                         mot_val[1 + stride] =
 753                         mot_val[3 + stride] = my;
 754                     } else {
 755                         int i;
 756                         s->current_picture.mb_type[xy] = MB_TYPE_8x8 |
 757                                                          MB_TYPE_L0;
 758                         for (i = 0; i < 4; i++) {
 759                             int16_t *mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 760                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
 761                             if (mx >= 0xffff)
 762                                 return -1;
 763
 764                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
 765                             if (my >= 0xffff)
 766                                 return -1;
 767                             mot_val[0] = mx;
 768                             mot_val[1] = my;
 769                         }
 770                     }
 771                 }
 772             }
 773         }
 774         s->mb_x = 0;
 775     }
 776
 777     return mb_num;
 778 }
 779
 780 /**
 781  * decode second partition.
 782  * @return <0 if an error occurred
 783  */
 784 static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count)
 785 {
 786     int mb_num = 0;
 787     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 788
 789     s->mb_x = s->resync_mb_x;
 790     s->first_slice_line = 1;
 791     for (s->mb_y = s->resync_mb_y; mb_num < mb_count; s->mb_y++) {
 792         ff_init_block_index(s);
 793         for (; mb_num < mb_count && s->mb_x < s->mb_width; s->mb_x++) {
 794             const int xy = s->mb_x + s->mb_y * s->mb_stride;
 795
 796             mb_num++;
 797             ff_update_block_index(s);
 798             if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
 799                 s->first_slice_line = 0;
 800
 801             if (s->pict_type == AV_PICTURE_TYPE_I) {
 802                 int ac_pred = get_bits1(&s->gb);
 803                 int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 804                 if (cbpy < 0) {
 805                     av_log(s->avctx, AV_LOG_ERROR,
 806                            "cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 807                     return -1;
 808                 }
 809
 810                 s->cbp_table[xy]               |= cbpy << 2;
 811                 s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
 812             } else { /* P || S_TYPE */
 813                 if (IS_INTRA(s->current_picture.mb_type[xy])) {
 814                     int i;
 815                     int dir     = 0;
 816                     int ac_pred = get_bits1(&s->gb);
 817                     int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 818
 819                     if (cbpy < 0) {
 820                         av_log(s->avctx, AV_LOG_ERROR,
 821                                "I cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 822                         return -1;
 823                     }
 824
 825                     if (s->cbp_table[xy] & 8)
 826                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 827                     s->current_picture.qscale_table[xy] = s->qscale;
 828
 829                     for (i = 0; i < 6; i++) {
 830                         int dc_pred_dir;
 831                         int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
 832                         if (dc < 0) {
 833                             av_log(s->avctx, AV_LOG_ERROR,
 834                                    "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 835                             return -1;
 836                         }
 837                         dir <<= 1;
 838                         if (dc_pred_dir)
 839                             dir |= 1;
 840                     }
 841                     s->cbp_table[xy]               &= 3;  // remove dquant
 842                     s->cbp_table[xy]               |= cbpy << 2;
 843                     s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
 844                     s->pred_dir_table[xy]           = dir;
 845                 } else if (IS_SKIP(s->current_picture.mb_type[xy])) {
 846                     s->current_picture.qscale_table[xy] = s->qscale;
 847                     s->cbp_table[xy]                    = 0;
 848                 } else {
 849                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 850
 851                     if (cbpy < 0) {
 852                         av_log(s->avctx, AV_LOG_ERROR,
 853                                "P cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 854                         return -1;
 855                     }
 856
 857                     if (s->cbp_table[xy] & 8)
 858                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 859                     s->current_picture.qscale_table[xy] = s->qscale;
 860
 861                     s->cbp_table[xy] &= 3;  // remove dquant
 862                     s->cbp_table[xy] |= (cbpy ^ 0xf) << 2;
 863                 }
 864             }
 865         }
 866         if (mb_num >= mb_count)
 867             return 0;
 868         s->mb_x = 0;
 869     }
 870     return 0;
 871 }
 872
 873 /**
 874  * Decode the first and second partition.
 875  * @return <0 if error (and sets error type in the error_status_table)
 876  */
 877 int ff_mpeg4_decode_partitions(Mpeg4DecContext *ctx)
 878 {
 879     MpegEncContext *s = &ctx->m;
 880     int mb_num;
 881     const int part_a_error = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_ERROR | ER_MV_ERROR) : ER_MV_ERROR;
 882     const int part_a_end   = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_END   | ER_MV_END)   : ER_MV_END;
 883
 884     mb_num = mpeg4_decode_partition_a(ctx);
 885     if (mb_num < 0) {
 886         ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 887                         s->mb_x, s->mb_y, part_a_error);
 888         return -1;
 889     }
 890
 891     if (s->resync_mb_x + s->resync_mb_y * s->mb_width + mb_num > s->mb_num) {
 892         av_log(s->avctx, AV_LOG_ERROR, "slice below monitor ...\n");
 893         ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 894                         s->mb_x, s->mb_y, part_a_error);
 895         return -1;
 896     }
 897
 898     s->mb_num_left = mb_num;
 899
 900     if (s->pict_type == AV_PICTURE_TYPE_I) {
 901         while (show_bits(&s->gb, 9) == 1)
 902             skip_bits(&s->gb, 9);
 903         if (get_bits_long(&s->gb, 19) != DC_MARKER) {
 904             av_log(s->avctx, AV_LOG_ERROR,
 905                    "marker missing after first I partition at %d %d\n",
 906                    s->mb_x, s->mb_y);
 907             return -1;
 908         }
 909     } else {
 910         while (show_bits(&s->gb, 10) == 1)
 911             skip_bits(&s->gb, 10);
 912         if (get_bits(&s->gb, 17) != MOTION_MARKER) {
 913             av_log(s->avctx, AV_LOG_ERROR,
 914                    "marker missing after first P partition at %d %d\n",
 915                    s->mb_x, s->mb_y);
 916             return -1;
 917         }
 918     }
 919     ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 920                     s->mb_x - 1, s->mb_y, part_a_end);
 921
 922     if (mpeg4_decode_partition_b(s, mb_num) < 0) {
 923         if (s->pict_type == AV_PICTURE_TYPE_P)
 924             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 925                             s->mb_x, s->mb_y, ER_DC_ERROR);
 926         return -1;
 927     } else {
 928         if (s->pict_type == AV_PICTURE_TYPE_P)
 929             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 930                             s->mb_x - 1, s->mb_y, ER_DC_END);
 931     }
 932
 933     return 0;
 934 }
 935
 936 /**
 937  * Decode a block.
 938  * @return <0 if an error occurred
 939  */
 940 static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
 941                                      int n, int coded, int intra, int rvlc)
 942 {
 943     MpegEncContext *s = &ctx->m;
 944     int level, i, last, run, qmul, qadd;
 945     int av_uninit(dc_pred_dir);
 946     RLTable *rl;
 947     RL_VLC_ELEM *rl_vlc;
 948     const uint8_t *scan_table;
 949
 950     // Note intra & rvlc should be optimized away if this is inlined
 951
 952     if (intra) {
 953         if (ctx->use_intra_dc_vlc) {
 954             /* DC coef */
 955             if (s->partitioned_frame) {
 956                 level = s->dc_val[0][s->block_index[n]];
 957                 if (n < 4)
 958                     level = FASTDIV((level + (s->y_dc_scale >> 1)), s->y_dc_scale);
 959                 else
 960                     level = FASTDIV((level + (s->c_dc_scale >> 1)), s->c_dc_scale);
 961                 dc_pred_dir = (s->pred_dir_table[s->mb_x + s->mb_y * s->mb_stride] << n) & 32;
 962             } else {
 963                 level = mpeg4_decode_dc(s, n, &dc_pred_dir);
 964                 if (level < 0)
 965                     return -1;
 966             }
 967             block[0] = level;
 968             i        = 0;
 969         } else {
 970             i = -1;
 971             ff_mpeg4_pred_dc(s, n, 0, &dc_pred_dir, 0);
 972         }
 973         if (!coded)
 974             goto not_coded;
 975
 976         if (rvlc) {
 977             rl     = &ff_rvlc_rl_intra;
 978             rl_vlc = ff_rvlc_rl_intra.rl_vlc[0];
 979         } else {
 980             rl     = &ff_mpeg4_rl_intra;
 981             rl_vlc = ff_mpeg4_rl_intra.rl_vlc[0];
 982         }
 983         if (s->ac_pred) {
 984             if (dc_pred_dir == 0)
 985                 scan_table = s->intra_v_scantable.permutated;  /* left */
 986             else
 987                 scan_table = s->intra_h_scantable.permutated;  /* top */
 988         } else {
 989             scan_table = s->intra_scantable.permutated;
 990         }
 991         qmul = 1;
 992         qadd = 0;
 993     } else {
 994         i = -1;
 995         if (!coded) {
 996             s->block_last_index[n] = i;
 997             return 0;
 998         }
 999         if (rvlc)
1000             rl = &ff_rvlc_rl_inter;
1001         else
1002             rl = &ff_h263_rl_inter;
1003
1004         scan_table = s->intra_scantable.permutated;
1005
1006         if (s->mpeg_quant) {
1007             qmul = 1;
1008             qadd = 0;
1009             if (rvlc)
1010                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[0];
1011             else
1012                 rl_vlc = ff_h263_rl_inter.rl_vlc[0];
1013         } else {
1014             qmul = s->qscale << 1;
1015             qadd = (s->qscale - 1) | 1;
1016             if (rvlc)
1017                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[s->qscale];
1018             else
1019                 rl_vlc = ff_h263_rl_inter.rl_vlc[s->qscale];
1020         }
1021     }
1022     {
1023         OPEN_READER(re, &s->gb);
1024         for (;;) {
1025             UPDATE_CACHE(re, &s->gb);
1026             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
1027             if (level == 0) {
1028                 /* escape */
1029                 if (rvlc) {
1030                     if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1031                         av_log(s->avctx, AV_LOG_ERROR,
1032                                "1. marker bit missing in rvlc esc\n");
1033                         return -1;
1034                     }
1035                     SKIP_CACHE(re, &s->gb, 1);
1036
1037                     last = SHOW_UBITS(re, &s->gb, 1);
1038                     SKIP_CACHE(re, &s->gb, 1);
1039                     run = SHOW_UBITS(re, &s->gb, 6);
1040                     SKIP_COUNTER(re, &s->gb, 1 + 1 + 6);
1041                     UPDATE_CACHE(re, &s->gb);
1042
1043                     if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1044                         av_log(s->avctx, AV_LOG_ERROR,
1045                                "2. marker bit missing in rvlc esc\n");
1046                         return -1;
1047                     }
1048                     SKIP_CACHE(re, &s->gb, 1);
1049
1050                     level = SHOW_UBITS(re, &s->gb, 11);
1051                     SKIP_CACHE(re, &s->gb, 11);
1052
1053                     if (SHOW_UBITS(re, &s->gb, 5) != 0x10) {
1054                         av_log(s->avctx, AV_LOG_ERROR, "reverse esc missing\n");
1055                         return -1;
1056                     }
1057                     SKIP_CACHE(re, &s->gb, 5);
1058
1059                     level = level * qmul + qadd;
1060                     level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1061                     SKIP_COUNTER(re, &s->gb, 1 + 11 + 5 + 1);
1062
1063                     i += run + 1;
1064                     if (last)
1065                         i += 192;
1066                 } else {
1067                     int cache;
1068                     cache = GET_CACHE(re, &s->gb);
1069
1070                     if (IS_3IV1)
1071                         cache ^= 0xC0000000;
1072
1073                     if (cache & 0x80000000) {
1074                         if (cache & 0x40000000) {
1075                             /* third escape */
1076                             SKIP_CACHE(re, &s->gb, 2);
1077                             last = SHOW_UBITS(re, &s->gb, 1);
1078                             SKIP_CACHE(re, &s->gb, 1);
1079                             run = SHOW_UBITS(re, &s->gb, 6);
1080                             SKIP_COUNTER(re, &s->gb, 2 + 1 + 6);
1081                             UPDATE_CACHE(re, &s->gb);
1082
1083                             if (IS_3IV1) {
1084                                 level = SHOW_SBITS(re, &s->gb, 12);
1085                                 LAST_SKIP_BITS(re, &s->gb, 12);
1086                             } else {
1087                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1088                                     av_log(s->avctx, AV_LOG_ERROR,
1089                                            "1. marker bit missing in 3. esc\n");
1090                                     if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR))
1091                                         return -1;
1092                                 }
1093                                 SKIP_CACHE(re, &s->gb, 1);
1094
1095                                 level = SHOW_SBITS(re, &s->gb, 12);
1096                                 SKIP_CACHE(re, &s->gb, 12);
1097
1098                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1099                                     av_log(s->avctx, AV_LOG_ERROR,
1100                                            "2. marker bit missing in 3. esc\n");
1101                                     if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR))
1102                                         return -1;
1103                                 }
1104
1105                                 SKIP_COUNTER(re, &s->gb, 1 + 12 + 1);
1106                             }
1107
1108 #if 0
1109                             if (s->error_recognition >= FF_ER_COMPLIANT) {
1110                                 const int abs_level= FFABS(level);
1111                                 if (abs_level<=MAX_LEVEL && run<=MAX_RUN) {
1112                                     const int run1= run - rl->max_run[last][abs_level] - 1;
1113                                     if (abs_level <= rl->max_level[last][run]) {
1114                                         av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, vlc encoding possible\n");
1115                                         return -1;
1116                                     }
1117                                     if (s->error_recognition > FF_ER_COMPLIANT) {
1118                                         if (abs_level <= rl->max_level[last][run]*2) {
1119                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 1 encoding possible\n");
1120                                             return -1;
1121                                         }
1122                                         if (run1 >= 0 && abs_level <= rl->max_level[last][run1]) {
1123                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 2 encoding possible\n");
1124                                             return -1;
1125                                         }
1126                                     }
1127                                 }
1128                             }
1129 #endif
1130                             if (level > 0)
1131                                 level = level * qmul + qadd;
1132                             else
1133                                 level = level * qmul - qadd;
1134
1135                             if ((unsigned)(level + 2048) > 4095) {
1136                                 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_AGGRESSIVE)) {
1137                                     if (level > 2560 || level < -2560) {
1138                                         av_log(s->avctx, AV_LOG_ERROR,
1139                                                "|level| overflow in 3. esc, qp=%d\n",
1140                                                s->qscale);
1141                                         return -1;
1142                                     }
1143                                 }
1144                                 level = level < 0 ? -2048 : 2047;
1145                             }
1146
1147                             i += run + 1;
1148                             if (last)
1149                                 i += 192;
1150                         } else {
1151                             /* second escape */
1152                             SKIP_BITS(re, &s->gb, 2);
1153                             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1154                             i    += run + rl->max_run[run >> 7][level / qmul] + 1;  // FIXME opt indexing
1155                             level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1156                             LAST_SKIP_BITS(re, &s->gb, 1);
1157                         }
1158                     } else {
1159                         /* first escape */
1160                         SKIP_BITS(re, &s->gb, 1);
1161                         GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1162                         i    += run;
1163                         level = level + rl->max_level[run >> 7][(run - 1) & 63] * qmul;  // FIXME opt indexing
1164                         level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1165                         LAST_SKIP_BITS(re, &s->gb, 1);
1166                     }
1167                 }
1168             } else {
1169                 i    += run;
1170                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1171                 LAST_SKIP_BITS(re, &s->gb, 1);
1172             }
1173             ff_tlog(s->avctx, "dct[%d][%d] = %- 4d end?:%d\n", scan_table[i&63]&7, scan_table[i&63] >> 3, level, i>62);
1174             if (i > 62) {
1175                 i -= 192;
1176                 if (i & (~63)) {
1177                     av_log(s->avctx, AV_LOG_ERROR,
1178                            "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1179                     return -1;
1180                 }
1181
1182                 block[scan_table[i]] = level;
1183                 break;
1184             }
1185
1186             block[scan_table[i]] = level;
1187         }
1188         CLOSE_READER(re, &s->gb);
1189     }
1190
1191 not_coded:
1192     if (intra) {
1193         if (!ctx->use_intra_dc_vlc) {
1194             block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0);
1195
1196             i -= i >> 31;  // if (i == -1) i = 0;
1197         }
1198
1199         ff_mpeg4_pred_ac(s, block, n, dc_pred_dir);
1200         if (s->ac_pred)
1201             i = 63;  // FIXME not optimal
1202     }
1203     s->block_last_index[n] = i;
1204     return 0;
1205 }
1206
1207 /**
1208  * decode partition C of one MB.
1209  * @return <0 if an error occurred
1210  */
1211 static int mpeg4_decode_partitioned_mb(MpegEncContext *s, int16_t block[6][64])
1212 {
1213     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1214     int cbp, mb_type;
1215     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1216
1217     mb_type = s->current_picture.mb_type[xy];
1218     cbp     = s->cbp_table[xy];
1219
1220     ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1221
1222     if (s->current_picture.qscale_table[xy] != s->qscale)
1223         ff_set_qscale(s, s->current_picture.qscale_table[xy]);
1224
1225     if (s->pict_type == AV_PICTURE_TYPE_P ||
1226         s->pict_type == AV_PICTURE_TYPE_S) {
1227         int i;
1228         for (i = 0; i < 4; i++) {
1229             s->mv[0][i][0] = s->current_picture.motion_val[0][s->block_index[i]][0];
1230             s->mv[0][i][1] = s->current_picture.motion_val[0][s->block_index[i]][1];
1231         }
1232         s->mb_intra = IS_INTRA(mb_type);
1233
1234         if (IS_SKIP(mb_type)) {
1235             /* skip mb */
1236             for (i = 0; i < 6; i++)
1237                 s->block_last_index[i] = -1;
1238             s->mv_dir  = MV_DIR_FORWARD;
1239             s->mv_type = MV_TYPE_16X16;
1240             if (s->pict_type == AV_PICTURE_TYPE_S
1241                 && ctx->vol_sprite_usage == GMC_SPRITE) {
1242                 s->mcsel      = 1;
1243                 s->mb_skipped = 0;
1244             } else {
1245                 s->mcsel      = 0;
1246                 s->mb_skipped = 1;
1247             }
1248         } else if (s->mb_intra) {
1249             s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1250         } else if (!s->mb_intra) {
1251             // s->mcsel = 0;  // FIXME do we need to init that?
1252
1253             s->mv_dir = MV_DIR_FORWARD;
1254             if (IS_8X8(mb_type)) {
1255                 s->mv_type = MV_TYPE_8X8;
1256             } else {
1257                 s->mv_type = MV_TYPE_16X16;
1258             }
1259         }
1260     } else { /* I-Frame */
1261         s->mb_intra = 1;
1262         s->ac_pred  = IS_ACPRED(s->current_picture.mb_type[xy]);
1263     }
1264
1265     if (!IS_SKIP(mb_type)) {
1266         int i;
1267         s->bdsp.clear_blocks(s->block[0]);
1268         /* decode each block */
1269         for (i = 0; i < 6; i++) {
1270             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, s->mb_intra, ctx->rvlc) < 0) {
1271                 av_log(s->avctx, AV_LOG_ERROR,
1272                        "texture corrupted at %d %d %d\n",
1273                        s->mb_x, s->mb_y, s->mb_intra);
1274                 return -1;
1275             }
1276             cbp += cbp;
1277         }
1278     }
1279
1280     /* per-MB end of slice check */
1281     if (--s->mb_num_left <= 0) {
1282         if (mpeg4_is_resync(ctx))
1283             return SLICE_END;
1284         else
1285             return SLICE_NOEND;
1286     } else {
1287         if (mpeg4_is_resync(ctx)) {
1288             const int delta = s->mb_x + 1 == s->mb_width ? 2 : 1;
1289             if (s->cbp_table[xy + delta])
1290                 return SLICE_END;
1291         }
1292         return SLICE_OK;
1293     }
1294 }
1295
1296 static int mpeg4_decode_mb(MpegEncContext *s, int16_t block[6][64])
1297 {
1298     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1299     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
1300     int16_t *mot_val;
1301     static int8_t quant_tab[4] = { -1, -2, 1, 2 };
1302     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1303
1304     av_assert2(s->h263_pred);
1305
1306     if (s->pict_type == AV_PICTURE_TYPE_P ||
1307         s->pict_type == AV_PICTURE_TYPE_S) {
1308         do {
1309             if (get_bits1(&s->gb)) {
1310                 /* skip mb */
1311                 s->mb_intra = 0;
1312                 for (i = 0; i < 6; i++)
1313                     s->block_last_index[i] = -1;
1314                 s->mv_dir  = MV_DIR_FORWARD;
1315                 s->mv_type = MV_TYPE_16X16;
1316                 if (s->pict_type == AV_PICTURE_TYPE_S &&
1317                     ctx->vol_sprite_usage == GMC_SPRITE) {
1318                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1319                                                      MB_TYPE_GMC   |
1320                                                      MB_TYPE_16x16 |
1321                                                      MB_TYPE_L0;
1322                     s->mcsel       = 1;
1323                     s->mv[0][0][0] = get_amv(ctx, 0);
1324                     s->mv[0][0][1] = get_amv(ctx, 1);
1325                     s->mb_skipped  = 0;
1326                 } else {
1327                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1328                                                      MB_TYPE_16x16 |
1329                                                      MB_TYPE_L0;
1330                     s->mcsel       = 0;
1331                     s->mv[0][0][0] = 0;
1332                     s->mv[0][0][1] = 0;
1333                     s->mb_skipped  = 1;
1334                 }
1335                 goto end;
1336             }
1337             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
1338             if (cbpc < 0) {
1339                 av_log(s->avctx, AV_LOG_ERROR,
1340                        "mcbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1341                 return -1;
1342             }
1343         } while (cbpc == 20);
1344
1345         s->bdsp.clear_blocks(s->block[0]);
1346         dquant      = cbpc & 8;
1347         s->mb_intra = ((cbpc & 4) != 0);
1348         if (s->mb_intra)
1349             goto intra;
1350
1351         if (s->pict_type == AV_PICTURE_TYPE_S &&
1352             ctx->vol_sprite_usage == GMC_SPRITE && (cbpc & 16) == 0)
1353             s->mcsel = get_bits1(&s->gb);
1354         else
1355             s->mcsel = 0;
1356         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1) ^ 0x0F;
1357
1358         cbp = (cbpc & 3) | (cbpy << 2);
1359         if (dquant)
1360             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1361         if ((!s->progressive_sequence) &&
1362             (cbp || (s->workaround_bugs & FF_BUG_XVID_ILACE)))
1363             s->interlaced_dct = get_bits1(&s->gb);
1364
1365         s->mv_dir = MV_DIR_FORWARD;
1366         if ((cbpc & 16) == 0) {
1367             if (s->mcsel) {
1368                 s->current_picture.mb_type[xy] = MB_TYPE_GMC   |
1369                                                  MB_TYPE_16x16 |
1370                                                  MB_TYPE_L0;
1371                 /* 16x16 global motion prediction */
1372                 s->mv_type     = MV_TYPE_16X16;
1373                 mx             = get_amv(ctx, 0);
1374                 my             = get_amv(ctx, 1);
1375                 s->mv[0][0][0] = mx;
1376                 s->mv[0][0][1] = my;
1377             } else if ((!s->progressive_sequence) && get_bits1(&s->gb)) {
1378                 s->current_picture.mb_type[xy] = MB_TYPE_16x8 |
1379                                                  MB_TYPE_L0   |
1380                                                  MB_TYPE_INTERLACED;
1381                 /* 16x8 field motion prediction */
1382                 s->mv_type = MV_TYPE_FIELD;
1383
1384                 s->field_select[0][0] = get_bits1(&s->gb);
1385                 s->field_select[0][1] = get_bits1(&s->gb);
1386
1387                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1388
1389                 for (i = 0; i < 2; i++) {
1390                     mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1391                     if (mx >= 0xffff)
1392                         return -1;
1393
1394                     my = ff_h263_decode_motion(s, pred_y / 2, s->f_code);
1395                     if (my >= 0xffff)
1396                         return -1;
1397
1398                     s->mv[0][i][0] = mx;
1399                     s->mv[0][i][1] = my;
1400                 }
1401             } else {
1402                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
1403                 /* 16x16 motion prediction */
1404                 s->mv_type = MV_TYPE_16X16;
1405                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1406                 mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1407
1408                 if (mx >= 0xffff)
1409                     return -1;
1410
1411                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1412
1413                 if (my >= 0xffff)
1414                     return -1;
1415                 s->mv[0][0][0] = mx;
1416                 s->mv[0][0][1] = my;
1417             }
1418         } else {
1419             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
1420             s->mv_type                     = MV_TYPE_8X8;
1421             for (i = 0; i < 4; i++) {
1422                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
1423                 mx      = ff_h263_decode_motion(s, pred_x, s->f_code);
1424                 if (mx >= 0xffff)
1425                     return -1;
1426
1427                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1428                 if (my >= 0xffff)
1429                     return -1;
1430                 s->mv[0][i][0] = mx;
1431                 s->mv[0][i][1] = my;
1432                 mot_val[0]     = mx;
1433                 mot_val[1]     = my;
1434             }
1435         }
1436     } else if (s->pict_type == AV_PICTURE_TYPE_B) {
1437         int modb1;   // first bit of modb
1438         int modb2;   // second bit of modb
1439         int mb_type;
1440
1441         s->mb_intra = 0;  // B-frames never contain intra blocks
1442         s->mcsel    = 0;  //      ...               true gmc blocks
1443
1444         if (s->mb_x == 0) {
1445             for (i = 0; i < 2; i++) {
1446                 s->last_mv[i][0][0] =
1447                 s->last_mv[i][0][1] =
1448                 s->last_mv[i][1][0] =
1449                 s->last_mv[i][1][1] = 0;
1450             }
1451
1452             ff_thread_await_progress(&s->next_picture_ptr->tf, s->mb_y, 0);
1453         }
1454
1455         /* if we skipped it in the future P Frame than skip it now too */
1456         s->mb_skipped = s->next_picture.mbskip_table[s->mb_y * s->mb_stride + s->mb_x];  // Note, skiptab=0 if last was GMC
1457
1458         if (s->mb_skipped) {
1459             /* skip mb */
1460             for (i = 0; i < 6; i++)
1461                 s->block_last_index[i] = -1;
1462
1463             s->mv_dir      = MV_DIR_FORWARD;
1464             s->mv_type     = MV_TYPE_16X16;
1465             s->mv[0][0][0] =
1466             s->mv[0][0][1] =
1467             s->mv[1][0][0] =
1468             s->mv[1][0][1] = 0;
1469             s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1470                                              MB_TYPE_16x16 |
1471                                              MB_TYPE_L0;
1472             goto end;
1473         }
1474
1475         modb1 = get_bits1(&s->gb);
1476         if (modb1) {
1477             // like MB_TYPE_B_DIRECT but no vectors coded
1478             mb_type = MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1;
1479             cbp     = 0;
1480         } else {
1481             modb2   = get_bits1(&s->gb);
1482             mb_type = get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
1483             if (mb_type < 0) {
1484                 av_log(s->avctx, AV_LOG_ERROR, "illegal MB_type\n");
1485                 return -1;
1486             }
1487             mb_type = mb_type_b_map[mb_type];
1488             if (modb2) {
1489                 cbp = 0;
1490             } else {
1491                 s->bdsp.clear_blocks(s->block[0]);
1492                 cbp = get_bits(&s->gb, 6);
1493             }
1494
1495             if ((!IS_DIRECT(mb_type)) && cbp) {
1496                 if (get_bits1(&s->gb))
1497                     ff_set_qscale(s, s->qscale + get_bits1(&s->gb) * 4 - 2);
1498             }
1499
1500             if (!s->progressive_sequence) {
1501                 if (cbp)
1502                     s->interlaced_dct = get_bits1(&s->gb);
1503
1504                 if (!IS_DIRECT(mb_type) && get_bits1(&s->gb)) {
1505                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
1506                     mb_type &= ~MB_TYPE_16x16;
1507
1508                     if (USES_LIST(mb_type, 0)) {
1509                         s->field_select[0][0] = get_bits1(&s->gb);
1510                         s->field_select[0][1] = get_bits1(&s->gb);
1511                     }
1512                     if (USES_LIST(mb_type, 1)) {
1513                         s->field_select[1][0] = get_bits1(&s->gb);
1514                         s->field_select[1][1] = get_bits1(&s->gb);
1515                     }
1516                 }
1517             }
1518
1519             s->mv_dir = 0;
1520             if ((mb_type & (MB_TYPE_DIRECT2 | MB_TYPE_INTERLACED)) == 0) {
1521                 s->mv_type = MV_TYPE_16X16;
1522
1523                 if (USES_LIST(mb_type, 0)) {
1524                     s->mv_dir = MV_DIR_FORWARD;
1525
1526                     mx = ff_h263_decode_motion(s, s->last_mv[0][0][0], s->f_code);
1527                     my = ff_h263_decode_motion(s, s->last_mv[0][0][1], s->f_code);
1528                     s->last_mv[0][1][0] =
1529                     s->last_mv[0][0][0] =
1530                     s->mv[0][0][0]      = mx;
1531                     s->last_mv[0][1][1] =
1532                     s->last_mv[0][0][1] =
1533                     s->mv[0][0][1]      = my;
1534                 }
1535
1536                 if (USES_LIST(mb_type, 1)) {
1537                     s->mv_dir |= MV_DIR_BACKWARD;
1538
1539                     mx = ff_h263_decode_motion(s, s->last_mv[1][0][0], s->b_code);
1540                     my = ff_h263_decode_motion(s, s->last_mv[1][0][1], s->b_code);
1541                     s->last_mv[1][1][0] =
1542                     s->last_mv[1][0][0] =
1543                     s->mv[1][0][0]      = mx;
1544                     s->last_mv[1][1][1] =
1545                     s->last_mv[1][0][1] =
1546                     s->mv[1][0][1]      = my;
1547                 }
1548             } else if (!IS_DIRECT(mb_type)) {
1549                 s->mv_type = MV_TYPE_FIELD;
1550
1551                 if (USES_LIST(mb_type, 0)) {
1552                     s->mv_dir = MV_DIR_FORWARD;
1553
1554                     for (i = 0; i < 2; i++) {
1555                         mx = ff_h263_decode_motion(s, s->last_mv[0][i][0], s->f_code);
1556                         my = ff_h263_decode_motion(s, s->last_mv[0][i][1] / 2, s->f_code);
1557                         s->last_mv[0][i][0] =
1558                         s->mv[0][i][0]      = mx;
1559                         s->last_mv[0][i][1] = (s->mv[0][i][1] = my) * 2;
1560                     }
1561                 }
1562
1563                 if (USES_LIST(mb_type, 1)) {
1564                     s->mv_dir |= MV_DIR_BACKWARD;
1565
1566                     for (i = 0; i < 2; i++) {
1567                         mx = ff_h263_decode_motion(s, s->last_mv[1][i][0], s->b_code);
1568                         my = ff_h263_decode_motion(s, s->last_mv[1][i][1] / 2, s->b_code);
1569                         s->last_mv[1][i][0] =
1570                         s->mv[1][i][0]      = mx;
1571                         s->last_mv[1][i][1] = (s->mv[1][i][1] = my) * 2;
1572                     }
1573                 }
1574             }
1575         }
1576
1577         if (IS_DIRECT(mb_type)) {
1578             if (IS_SKIP(mb_type)) {
1579                 mx =
1580                 my = 0;
1581             } else {
1582                 mx = ff_h263_decode_motion(s, 0, 1);
1583                 my = ff_h263_decode_motion(s, 0, 1);
1584             }
1585
1586             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
1587             mb_type  |= ff_mpeg4_set_direct_mv(s, mx, my);
1588         }
1589         s->current_picture.mb_type[xy] = mb_type;
1590     } else { /* I-Frame */
1591         do {
1592             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
1593             if (cbpc < 0) {
1594                 av_log(s->avctx, AV_LOG_ERROR,
1595                        "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1596                 return -1;
1597             }
1598         } while (cbpc == 8);
1599
1600         dquant = cbpc & 4;
1601         s->mb_intra = 1;
1602
1603 intra:
1604         s->ac_pred = get_bits1(&s->gb);
1605         if (s->ac_pred)
1606             s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
1607         else
1608             s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
1609
1610         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
1611         if (cbpy < 0) {
1612             av_log(s->avctx, AV_LOG_ERROR,
1613                    "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
1614             return -1;
1615         }
1616         cbp = (cbpc & 3) | (cbpy << 2);
1617
1618         ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1619
1620         if (dquant)
1621             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1622
1623         if (!s->progressive_sequence)
1624             s->interlaced_dct = get_bits1(&s->gb);
1625
1626         s->bdsp.clear_blocks(s->block[0]);
1627         /* decode each block */
1628         for (i = 0; i < 6; i++) {
1629             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 1, 0) < 0)
1630                 return -1;
1631             cbp += cbp;
1632         }
1633         goto end;
1634     }
1635
1636     /* decode each block */
1637     for (i = 0; i < 6; i++) {
1638         if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 0, 0) < 0)
1639             return -1;
1640         cbp += cbp;
1641     }
1642
1643 end:
1644     /* per-MB end of slice check */
1645     if (s->codec_id == AV_CODEC_ID_MPEG4) {
1646         int next = mpeg4_is_resync(ctx);
1647         if (next) {
1648             if        (s->mb_x + s->mb_y*s->mb_width + 1 >  next && (s->avctx->err_recognition & AV_EF_AGGRESSIVE)) {
1649                 return -1;
1650             } else if (s->mb_x + s->mb_y*s->mb_width + 1 >= next)
1651                 return SLICE_END;
1652
1653             if (s->pict_type == AV_PICTURE_TYPE_B) {
1654                 const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1655                 ff_thread_await_progress(&s->next_picture_ptr->tf,
1656                                          (s->mb_x + delta >= s->mb_width)
1657                                          ? FFMIN(s->mb_y + 1, s->mb_height - 1)
1658                                          : s->mb_y, 0);
1659                 if (s->next_picture.mbskip_table[xy + delta])
1660                     return SLICE_OK;
1661             }
1662
1663             return SLICE_END;
1664         }
1665     }
1666
1667     return SLICE_OK;
1668 }
1669
1670 static int mpeg4_decode_gop_header(MpegEncContext *s, GetBitContext *gb)
1671 {
1672     int hours, minutes, seconds;
1673
1674     if (!show_bits(gb, 23)) {
1675         av_log(s->avctx, AV_LOG_WARNING, "GOP header invalid\n");
1676         return -1;
1677     }
1678
1679     hours   = get_bits(gb, 5);
1680     minutes = get_bits(gb, 6);
1681     check_marker(gb, "in gop_header");
1682     seconds = get_bits(gb, 6);
1683
1684     s->time_base = seconds + 60*(minutes + 60*hours);
1685
1686     skip_bits1(gb);
1687     skip_bits1(gb);
1688
1689     return 0;
1690 }
1691
1692 static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb)
1693 {
1694
1695     s->avctx->profile = get_bits(gb, 4);
1696     s->avctx->level   = get_bits(gb, 4);
1697
1698     // for Simple profile, level 0
1699     if (s->avctx->profile == 0 && s->avctx->level == 8) {
1700         s->avctx->level = 0;
1701     }
1702
1703     return 0;
1704 }
1705
1706 static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
1707 {
1708     MpegEncContext *s = &ctx->m;
1709     int width, height, vo_ver_id;
1710
1711     /* vol header */
1712     skip_bits(gb, 1);                   /* random access */
1713     s->vo_type = get_bits(gb, 8);
1714     if (get_bits1(gb) != 0) {           /* is_ol_id */
1715         vo_ver_id = get_bits(gb, 4);    /* vo_ver_id */
1716         skip_bits(gb, 3);               /* vo_priority */
1717     } else {
1718         vo_ver_id = 1;
1719     }
1720     s->aspect_ratio_info = get_bits(gb, 4);
1721     if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1722         s->avctx->sample_aspect_ratio.num = get_bits(gb, 8);  // par_width
1723         s->avctx->sample_aspect_ratio.den = get_bits(gb, 8);  // par_height
1724     } else {
1725         s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[s->aspect_ratio_info];
1726     }
1727
1728     if ((ctx->vol_control_parameters = get_bits1(gb))) { /* vol control parameter */
1729         int chroma_format = get_bits(gb, 2);
1730         if (chroma_format != CHROMA_420)
1731             av_log(s->avctx, AV_LOG_ERROR, "illegal chroma format\n");
1732
1733         s->low_delay = get_bits1(gb);
1734         if (get_bits1(gb)) {    /* vbv parameters */
1735             get_bits(gb, 15);   /* first_half_bitrate */
1736             check_marker(gb, "after first_half_bitrate");
1737             get_bits(gb, 15);   /* latter_half_bitrate */
1738             check_marker(gb, "after latter_half_bitrate");
1739             get_bits(gb, 15);   /* first_half_vbv_buffer_size */
1740             check_marker(gb, "after first_half_vbv_buffer_size");
1741             get_bits(gb, 3);    /* latter_half_vbv_buffer_size */
1742             get_bits(gb, 11);   /* first_half_vbv_occupancy */
1743             check_marker(gb, "after first_half_vbv_occupancy");
1744             get_bits(gb, 15);   /* latter_half_vbv_occupancy */
1745             check_marker(gb, "after latter_half_vbv_occupancy");
1746         }
1747     } else {
1748         /* is setting low delay flag only once the smartest thing to do?
1749          * low delay detection won't be overridden. */
1750         if (s->picture_number == 0)
1751             s->low_delay = 0;
1752     }
1753
1754     ctx->shape = get_bits(gb, 2); /* vol shape */
1755     if (ctx->shape != RECT_SHAPE)
1756         av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
1757     if (ctx->shape == GRAY_SHAPE && vo_ver_id != 1) {
1758         av_log(s->avctx, AV_LOG_ERROR, "Gray shape not supported\n");
1759         skip_bits(gb, 4);  /* video_object_layer_shape_extension */
1760     }
1761
1762     check_marker(gb, "before time_increment_resolution");
1763
1764     s->avctx->framerate.num = get_bits(gb, 16);
1765     if (!s->avctx->framerate.num) {
1766         av_log(s->avctx, AV_LOG_ERROR, "framerate==0\n");
1767         return AVERROR_INVALIDDATA;
1768     }
1769
1770     ctx->time_increment_bits = av_log2(s->avctx->framerate.num - 1) + 1;
1771     if (ctx->time_increment_bits < 1)
1772         ctx->time_increment_bits = 1;
1773
1774     check_marker(gb, "before fixed_vop_rate");
1775
1776     if (get_bits1(gb) != 0)     /* fixed_vop_rate  */
1777         s->avctx->framerate.den = get_bits(gb, ctx->time_increment_bits);
1778     else
1779         s->avctx->framerate.den = 1;
1780
1781     s->avctx->time_base = av_inv_q(av_mul_q(s->avctx->framerate, (AVRational){s->avctx->ticks_per_frame, 1}));
1782
1783     ctx->t_frame = 0;
1784
1785     if (ctx->shape != BIN_ONLY_SHAPE) {
1786         if (ctx->shape == RECT_SHAPE) {
1787             check_marker(gb, "before width");
1788             width = get_bits(gb, 13);
1789             check_marker(gb, "before height");
1790             height = get_bits(gb, 13);
1791             check_marker(gb, "after height");
1792             if (width && height &&  /* they should be non zero but who knows */
1793                 !(s->width && s->codec_tag == AV_RL32("MP4S"))) {
1794                 if (s->width && s->height &&
1795                     (s->width != width || s->height != height))
1796                     s->context_reinit = 1;
1797                 s->width  = width;
1798                 s->height = height;
1799             }
1800         }
1801
1802         s->progressive_sequence  =
1803         s->progressive_frame     = get_bits1(gb) ^ 1;
1804         s->interlaced_dct        = 0;
1805         if (!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
1806             av_log(s->avctx, AV_LOG_INFO,           /* OBMC Disable */
1807                    "MPEG4 OBMC not supported (very likely buggy encoder)\n");
1808         if (vo_ver_id == 1)
1809             ctx->vol_sprite_usage = get_bits1(gb);    /* vol_sprite_usage */
1810         else
1811             ctx->vol_sprite_usage = get_bits(gb, 2);  /* vol_sprite_usage */
1812
1813         if (ctx->vol_sprite_usage == STATIC_SPRITE)
1814             av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
1815         if (ctx->vol_sprite_usage == STATIC_SPRITE ||
1816             ctx->vol_sprite_usage == GMC_SPRITE) {
1817             if (ctx->vol_sprite_usage == STATIC_SPRITE) {
1818                 skip_bits(gb, 13); // sprite_width
1819                 check_marker(gb, "after sprite_width");
1820                 skip_bits(gb, 13); // sprite_height
1821                 check_marker(gb, "after sprite_height");
1822                 skip_bits(gb, 13); // sprite_left
1823                 check_marker(gb, "after sprite_left");
1824                 skip_bits(gb, 13); // sprite_top
1825                 check_marker(gb, "after sprite_top");
1826             }
1827             ctx->num_sprite_warping_points = get_bits(gb, 6);
1828             if (ctx->num_sprite_warping_points > 3) {
1829                 av_log(s->avctx, AV_LOG_ERROR,
1830                        "%d sprite_warping_points\n",
1831                        ctx->num_sprite_warping_points);
1832                 ctx->num_sprite_warping_points = 0;
1833                 return AVERROR_INVALIDDATA;
1834             }
1835             s->sprite_warping_accuracy  = get_bits(gb, 2);
1836             ctx->sprite_brightness_change = get_bits1(gb);
1837             if (ctx->vol_sprite_usage == STATIC_SPRITE)
1838                 skip_bits1(gb); // low_latency_sprite
1839         }
1840         // FIXME sadct disable bit if verid!=1 && shape not rect
1841
1842         if (get_bits1(gb) == 1) {                   /* not_8_bit */
1843             s->quant_precision = get_bits(gb, 4);   /* quant_precision */
1844             if (get_bits(gb, 4) != 8)               /* bits_per_pixel */
1845                 av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n");
1846             if (s->quant_precision != 5)
1847                 av_log(s->avctx, AV_LOG_ERROR,
1848                        "quant precision %d\n", s->quant_precision);
1849             if (s->quant_precision<3 || s->quant_precision>9) {
1850                 s->quant_precision = 5;
1851             }
1852         } else {
1853             s->quant_precision = 5;
1854         }
1855
1856         // FIXME a bunch of grayscale shape things
1857
1858         if ((s->mpeg_quant = get_bits1(gb))) { /* vol_quant_type */
1859             int i, v;
1860
1861             /* load default matrixes */
1862             for (i = 0; i < 64; i++) {
1863                 int j = s->idsp.idct_permutation[i];
1864                 v = ff_mpeg4_default_intra_matrix[i];
1865                 s->intra_matrix[j]        = v;
1866                 s->chroma_intra_matrix[j] = v;
1867
1868                 v = ff_mpeg4_default_non_intra_matrix[i];
1869                 s->inter_matrix[j]        = v;
1870                 s->chroma_inter_matrix[j] = v;
1871             }
1872
1873             /* load custom intra matrix */
1874             if (get_bits1(gb)) {
1875                 int last = 0;
1876                 for (i = 0; i < 64; i++) {
1877                     int j;
1878                     v = get_bits(gb, 8);
1879                     if (v == 0)
1880                         break;
1881
1882                     last = v;
1883                     j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1884                     s->intra_matrix[j]        = last;
1885                     s->chroma_intra_matrix[j] = last;
1886                 }
1887
1888                 /* replicate last value */
1889                 for (; i < 64; i++) {
1890                     int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1891                     s->intra_matrix[j]        = last;
1892                     s->chroma_intra_matrix[j] = last;
1893                 }
1894             }
1895
1896             /* load custom non intra matrix */
1897             if (get_bits1(gb)) {
1898                 int last = 0;
1899                 for (i = 0; i < 64; i++) {
1900                     int j;
1901                     v = get_bits(gb, 8);
1902                     if (v == 0)
1903                         break;
1904
1905                     last = v;
1906                     j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1907                     s->inter_matrix[j]        = v;
1908                     s->chroma_inter_matrix[j] = v;
1909                 }
1910
1911                 /* replicate last value */
1912                 for (; i < 64; i++) {
1913                     int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1914                     s->inter_matrix[j]        = last;
1915                     s->chroma_inter_matrix[j] = last;
1916                 }
1917             }
1918
1919             // FIXME a bunch of grayscale shape things
1920         }
1921
1922         if (vo_ver_id != 1)
1923             s->quarter_sample = get_bits1(gb);
1924         else
1925             s->quarter_sample = 0;
1926
1927         if (get_bits_left(gb) < 4) {
1928             av_log(s->avctx, AV_LOG_ERROR, "VOL Header truncated\n");
1929             return AVERROR_INVALIDDATA;
1930         }
1931
1932         if (!get_bits1(gb)) {
1933             int pos               = get_bits_count(gb);
1934             int estimation_method = get_bits(gb, 2);
1935             if (estimation_method < 2) {
1936                 if (!get_bits1(gb)) {
1937                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* opaque */
1938                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* transparent */
1939                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_cae */
1940                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* inter_cae */
1941                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* no_update */
1942                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* upampling */
1943                 }
1944                 if (!get_bits1(gb)) {
1945                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_blocks */
1946                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter_blocks */
1947                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter4v_blocks */
1948                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* not coded blocks */
1949                 }
1950                 if (!check_marker(gb, "in complexity estimation part 1")) {
1951                     skip_bits_long(gb, pos - get_bits_count(gb));
1952                     goto no_cplx_est;
1953                 }
1954                 if (!get_bits1(gb)) {
1955                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_coeffs */
1956                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_lines */
1957                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* vlc_syms */
1958                     ctx->cplx_estimation_trash_i += 4 * get_bits1(gb);  /* vlc_bits */
1959                 }
1960                 if (!get_bits1(gb)) {
1961                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* apm */
1962                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* npm */
1963                     ctx->cplx_estimation_trash_b += 8 * get_bits1(gb);  /* interpolate_mc_q */
1964                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* forwback_mc_q */
1965                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel2 */
1966                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel4 */
1967                 }
1968                 if (!check_marker(gb, "in complexity estimation part 2")) {
1969                     skip_bits_long(gb, pos - get_bits_count(gb));
1970                     goto no_cplx_est;
1971                 }
1972                 if (estimation_method == 1) {
1973                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* sadct */
1974                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* qpel */
1975                 }
1976             } else
1977                 av_log(s->avctx, AV_LOG_ERROR,
1978                        "Invalid Complexity estimation method %d\n",
1979                        estimation_method);
1980         } else {
1981
1982 no_cplx_est:
1983             ctx->cplx_estimation_trash_i =
1984             ctx->cplx_estimation_trash_p =
1985             ctx->cplx_estimation_trash_b = 0;
1986         }
1987
1988         ctx->resync_marker = !get_bits1(gb); /* resync_marker_disabled */
1989
1990         s->data_partitioning = get_bits1(gb);
1991         if (s->data_partitioning)
1992             ctx->rvlc = get_bits1(gb);
1993
1994         if (vo_ver_id != 1) {
1995             ctx->new_pred = get_bits1(gb);
1996             if (ctx->new_pred) {
1997                 av_log(s->avctx, AV_LOG_ERROR, "new pred not supported\n");
1998                 skip_bits(gb, 2); /* requested upstream message type */
1999                 skip_bits1(gb);   /* newpred segment type */
2000             }
2001             if (get_bits1(gb)) // reduced_res_vop
2002                 av_log(s->avctx, AV_LOG_ERROR,
2003                        "reduced resolution VOP not supported\n");
2004         } else {
2005             ctx->new_pred = 0;
2006         }
2007
2008         ctx->scalability = get_bits1(gb);
2009
2010         if (ctx->scalability) {
2011             GetBitContext bak = *gb;
2012             int h_sampling_factor_n;
2013             int h_sampling_factor_m;
2014             int v_sampling_factor_n;
2015             int v_sampling_factor_m;
2016
2017             skip_bits1(gb);    // hierarchy_type
2018             skip_bits(gb, 4);  /* ref_layer_id */
2019             skip_bits1(gb);    /* ref_layer_sampling_dir */
2020             h_sampling_factor_n = get_bits(gb, 5);
2021             h_sampling_factor_m = get_bits(gb, 5);
2022             v_sampling_factor_n = get_bits(gb, 5);
2023             v_sampling_factor_m = get_bits(gb, 5);
2024             ctx->enhancement_type = get_bits1(gb);
2025
2026             if (h_sampling_factor_n == 0 || h_sampling_factor_m == 0 ||
2027                 v_sampling_factor_n == 0 || v_sampling_factor_m == 0) {
2028                 /* illegal scalability header (VERY broken encoder),
2029                  * trying to workaround */
2030                 ctx->scalability = 0;
2031                 *gb            = bak;
2032             } else
2033                 av_log(s->avctx, AV_LOG_ERROR, "scalability not supported\n");
2034
2035             // bin shape stuff FIXME
2036         }
2037     }
2038
2039     if (s->avctx->debug&FF_DEBUG_PICT_INFO) {
2040         av_log(s->avctx, AV_LOG_DEBUG, "tb %d/%d, tincrbits:%d, qp_prec:%d, ps:%d,  %s%s%s%s\n",
2041                s->avctx->framerate.den, s->avctx->framerate.num,
2042                ctx->time_increment_bits,
2043                s->quant_precision,
2044                s->progressive_sequence,
2045                ctx->scalability ? "scalability " :"" , s->quarter_sample ? "qpel " : "",
2046                s->data_partitioning ? "partition " : "", ctx->rvlc ? "rvlc " : ""
2047         );
2048     }
2049
2050     return 0;
2051 }
2052
2053 /**
2054  * Decode the user data stuff in the header.
2055  * Also initializes divx/xvid/lavc_version/build.
2056  */
2057 static int decode_user_data(Mpeg4DecContext *ctx, GetBitContext *gb)
2058 {
2059     MpegEncContext *s = &ctx->m;
2060     char buf[256];
2061     int i;
2062     int e;
2063     int ver = 0, build = 0, ver2 = 0, ver3 = 0;
2064     char last;
2065
2066     for (i = 0; i < 255 && get_bits_count(gb) < gb->size_in_bits; i++) {
2067         if (show_bits(gb, 23) == 0)
2068             break;
2069         buf[i] = get_bits(gb, 8);
2070     }
2071     buf[i] = 0;
2072
2073     /* divx detection */
2074     e = sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
2075     if (e < 2)
2076         e = sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
2077     if (e >= 2) {
2078         ctx->divx_version = ver;
2079         ctx->divx_build   = build;
2080         s->divx_packed  = e == 3 && last == 'p';
2081     }
2082
2083     /* libavcodec detection */
2084     e = sscanf(buf, "FFmpe%*[^b]b%d", &build) + 3;
2085     if (e != 4)
2086         e = sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
2087     if (e != 4) {
2088         e = sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3) + 1;
2089         if (e > 1)
2090             build = (ver << 16) + (ver2 << 8) + ver3;
2091     }
2092     if (e != 4) {
2093         if (strcmp(buf, "ffmpeg") == 0)
2094             ctx->lavc_build = 4600;
2095     }
2096     if (e == 4)
2097         ctx->lavc_build = build;
2098
2099     /* Xvid detection */
2100     e = sscanf(buf, "XviD%d", &build);
2101     if (e == 1)
2102         ctx->xvid_build = build;
2103
2104     return 0;
2105 }
2106
2107 int ff_mpeg4_workaround_bugs(AVCodecContext *avctx)
2108 {
2109     Mpeg4DecContext *ctx = avctx->priv_data;
2110     MpegEncContext *s = &ctx->m;
2111
2112     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1) {
2113         if (s->codec_tag        == AV_RL32("XVID") ||
2114             s->codec_tag        == AV_RL32("XVIX") ||
2115             s->codec_tag        == AV_RL32("RMP4") ||
2116             s->codec_tag        == AV_RL32("ZMP4") ||
2117             s->codec_tag        == AV_RL32("SIPP"))
2118             ctx->xvid_build = 0;
2119     }
2120
2121     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1)
2122         if (s->codec_tag == AV_RL32("DIVX") && s->vo_type == 0 &&
2123             ctx->vol_control_parameters == 0)
2124             ctx->divx_version = 400;  // divx 4
2125
2126     if (ctx->xvid_build >= 0 && ctx->divx_version >= 0) {
2127         ctx->divx_version =
2128         ctx->divx_build   = -1;
2129     }
2130
2131     if (s->workaround_bugs & FF_BUG_AUTODETECT) {
2132         if (s->codec_tag == AV_RL32("XVIX"))
2133             s->workaround_bugs |= FF_BUG_XVID_ILACE;
2134
2135         if (s->codec_tag == AV_RL32("UMP4"))
2136             s->workaround_bugs |= FF_BUG_UMP4;
2137
2138         if (ctx->divx_version >= 500 && ctx->divx_build < 1814)
2139             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2140
2141         if (ctx->divx_version > 502 && ctx->divx_build < 1814)
2142             s->workaround_bugs |= FF_BUG_QPEL_CHROMA2;
2143
2144         if (ctx->xvid_build <= 3U)
2145             s->padding_bug_score = 256 * 256 * 256 * 64;
2146
2147         if (ctx->xvid_build <= 1U)
2148             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2149
2150         if (ctx->xvid_build <= 12U)
2151             s->workaround_bugs |= FF_BUG_EDGE;
2152
2153         if (ctx->xvid_build <= 32U)
2154             s->workaround_bugs |= FF_BUG_DC_CLIP;
2155
2156 #define SET_QPEL_FUNC(postfix1, postfix2)                           \
2157     s->qdsp.put_        ## postfix1 = ff_put_        ## postfix2;   \
2158     s->qdsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;   \
2159     s->qdsp.avg_        ## postfix1 = ff_avg_        ## postfix2;
2160
2161         if (ctx->lavc_build < 4653U)
2162             s->workaround_bugs |= FF_BUG_STD_QPEL;
2163
2164         if (ctx->lavc_build < 4655U)
2165             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2166
2167         if (ctx->lavc_build < 4670U)
2168             s->workaround_bugs |= FF_BUG_EDGE;
2169
2170         if (ctx->lavc_build <= 4712U)
2171             s->workaround_bugs |= FF_BUG_DC_CLIP;
2172
2173         if (ctx->divx_version >= 0)
2174             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2175         if (ctx->divx_version == 501 && ctx->divx_build == 20020416)
2176             s->padding_bug_score = 256 * 256 * 256 * 64;
2177
2178         if (ctx->divx_version < 500U)
2179             s->workaround_bugs |= FF_BUG_EDGE;
2180
2181         if (ctx->divx_version >= 0)
2182             s->workaround_bugs |= FF_BUG_HPEL_CHROMA;
2183     }
2184
2185     if (s->workaround_bugs & FF_BUG_STD_QPEL) {
2186         SET_QPEL_FUNC(qpel_pixels_tab[0][5], qpel16_mc11_old_c)
2187         SET_QPEL_FUNC(qpel_pixels_tab[0][7], qpel16_mc31_old_c)
2188         SET_QPEL_FUNC(qpel_pixels_tab[0][9], qpel16_mc12_old_c)
2189         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
2190         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
2191         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
2192
2193         SET_QPEL_FUNC(qpel_pixels_tab[1][5], qpel8_mc11_old_c)
2194         SET_QPEL_FUNC(qpel_pixels_tab[1][7], qpel8_mc31_old_c)
2195         SET_QPEL_FUNC(qpel_pixels_tab[1][9], qpel8_mc12_old_c)
2196         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
2197         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
2198         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
2199     }
2200
2201     if (avctx->debug & FF_DEBUG_BUGS)
2202         av_log(s->avctx, AV_LOG_DEBUG,
2203                "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
2204                s->workaround_bugs, ctx->lavc_build, ctx->xvid_build,
2205                ctx->divx_version, ctx->divx_build, s->divx_packed ? "p" : "");
2206
2207     if (CONFIG_MPEG4_DECODER && ctx->xvid_build >= 0 &&
2208         s->codec_id == AV_CODEC_ID_MPEG4 &&
2209         avctx->idct_algo == FF_IDCT_AUTO) {
2210         avctx->idct_algo = FF_IDCT_XVID;
2211         ff_mpv_idct_init(s);
2212         return 1;
2213     }
2214
2215     return 0;
2216 }
2217
2218 static int decode_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2219 {
2220     MpegEncContext *s = &ctx->m;
2221     int time_incr, time_increment;
2222     int64_t pts;
2223
2224     s->pict_type = get_bits(gb, 2) + AV_PICTURE_TYPE_I;        /* pict type: I = 0 , P = 1 */
2225     if (s->pict_type == AV_PICTURE_TYPE_B && s->low_delay &&
2226         ctx->vol_control_parameters == 0 && !(s->avctx->flags & CODEC_FLAG_LOW_DELAY)) {
2227         av_log(s->avctx, AV_LOG_ERROR, "low_delay flag set incorrectly, clearing it\n");
2228         s->low_delay = 0;
2229     }
2230
2231     s->partitioned_frame = s->data_partitioning && s->pict_type != AV_PICTURE_TYPE_B;
2232     if (s->partitioned_frame)
2233         s->decode_mb = mpeg4_decode_partitioned_mb;
2234     else
2235         s->decode_mb = mpeg4_decode_mb;
2236
2237     time_incr = 0;
2238     while (get_bits1(gb) != 0)
2239         time_incr++;
2240
2241     check_marker(gb, "before time_increment");
2242
2243     if (ctx->time_increment_bits == 0 ||
2244         !(show_bits(gb, ctx->time_increment_bits + 1) & 1)) {
2245         av_log(s->avctx, AV_LOG_WARNING,
2246                "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);
2247
2248         for (ctx->time_increment_bits = 1;
2249              ctx->time_increment_bits < 16;
2250              ctx->time_increment_bits++) {
2251             if (s->pict_type == AV_PICTURE_TYPE_P ||
2252                 (s->pict_type == AV_PICTURE_TYPE_S &&
2253                  ctx->vol_sprite_usage == GMC_SPRITE)) {
2254                 if ((show_bits(gb, ctx->time_increment_bits + 6) & 0x37) == 0x30)
2255                     break;
2256             } else if ((show_bits(gb, ctx->time_increment_bits + 5) & 0x1F) == 0x18)
2257                 break;
2258         }
2259
2260         av_log(s->avctx, AV_LOG_WARNING,
2261                "time_increment_bits set to %d bits, based on bitstream analysis\n", ctx->time_increment_bits);
2262         if (s->avctx->framerate.num && 4*s->avctx->framerate.num < 1<<ctx->time_increment_bits) {
2263             s->avctx->framerate.num = 1<<ctx->time_increment_bits;
2264             s->avctx->time_base = av_inv_q(av_mul_q(s->avctx->framerate, (AVRational){s->avctx->ticks_per_frame, 1}));
2265         }
2266     }
2267
2268     if (IS_3IV1)
2269         time_increment = get_bits1(gb);        // FIXME investigate further
2270     else
2271         time_increment = get_bits(gb, ctx->time_increment_bits);
2272
2273     if (s->pict_type != AV_PICTURE_TYPE_B) {
2274         s->last_time_base = s->time_base;
2275         s->time_base     += time_incr;
2276         s->time = s->time_base * s->avctx->framerate.num + time_increment;
2277         if (s->workaround_bugs & FF_BUG_UMP4) {
2278             if (s->time < s->last_non_b_time) {
2279                 /* header is not mpeg-4-compatible, broken encoder,
2280                  * trying to workaround */
2281                 s->time_base++;
2282                 s->time += s->avctx->framerate.num;
2283             }
2284         }
2285         s->pp_time         = s->time - s->last_non_b_time;
2286         s->last_non_b_time = s->time;
2287     } else {
2288         s->time    = (s->last_time_base + time_incr) * s->avctx->framerate.num + time_increment;
2289         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
2290         if (s->pp_time <= s->pb_time ||
2291             s->pp_time <= s->pp_time - s->pb_time ||
2292             s->pp_time <= 0) {
2293             /* messed up order, maybe after seeking? skipping current b-frame */
2294             return FRAME_SKIPPED;
2295         }
2296         ff_mpeg4_init_direct_mv(s);
2297
2298         if (ctx->t_frame == 0)
2299             ctx->t_frame = s->pb_time;
2300         if (ctx->t_frame == 0)
2301             ctx->t_frame = 1;  // 1/0 protection
2302         s->pp_field_time = (ROUNDED_DIV(s->last_non_b_time, ctx->t_frame) -
2303                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2304         s->pb_field_time = (ROUNDED_DIV(s->time, ctx->t_frame) -
2305                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2306         if (s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1) {
2307             s->pb_field_time = 2;
2308             s->pp_field_time = 4;
2309             if (!s->progressive_sequence)
2310                 return FRAME_SKIPPED;
2311         }
2312     }
2313
2314     if (s->avctx->framerate.den)
2315         pts = ROUNDED_DIV(s->time, s->avctx->framerate.den);
2316     else
2317         pts = AV_NOPTS_VALUE;
2318     if (s->avctx->debug&FF_DEBUG_PTS)
2319         av_log(s->avctx, AV_LOG_DEBUG, "MPEG4 PTS: %"PRId64"\n",
2320                pts);
2321
2322     check_marker(gb, "before vop_coded");
2323
2324     /* vop coded */
2325     if (get_bits1(gb) != 1) {
2326         if (s->avctx->debug & FF_DEBUG_PICT_INFO)
2327             av_log(s->avctx, AV_LOG_ERROR, "vop not coded\n");
2328         return FRAME_SKIPPED;
2329     }
2330     if (ctx->new_pred)
2331         decode_new_pred(ctx, gb);
2332
2333     if (ctx->shape != BIN_ONLY_SHAPE &&
2334                     (s->pict_type == AV_PICTURE_TYPE_P ||
2335                      (s->pict_type == AV_PICTURE_TYPE_S &&
2336                       ctx->vol_sprite_usage == GMC_SPRITE))) {
2337         /* rounding type for motion estimation */
2338         s->no_rounding = get_bits1(gb);
2339     } else {
2340         s->no_rounding = 0;
2341     }
2342     // FIXME reduced res stuff
2343
2344     if (ctx->shape != RECT_SHAPE) {
2345         if (ctx->vol_sprite_usage != 1 || s->pict_type != AV_PICTURE_TYPE_I) {
2346             skip_bits(gb, 13);  /* width */
2347             check_marker(gb, "after width");
2348             skip_bits(gb, 13);  /* height */
2349             check_marker(gb, "after height");
2350             skip_bits(gb, 13);  /* hor_spat_ref */
2351             check_marker(gb, "after hor_spat_ref");
2352             skip_bits(gb, 13);  /* ver_spat_ref */
2353         }
2354         skip_bits1(gb);         /* change_CR_disable */
2355
2356         if (get_bits1(gb) != 0)
2357             skip_bits(gb, 8);   /* constant_alpha_value */
2358     }
2359
2360     // FIXME complexity estimation stuff
2361
2362     if (ctx->shape != BIN_ONLY_SHAPE) {
2363         skip_bits_long(gb, ctx->cplx_estimation_trash_i);
2364         if (s->pict_type != AV_PICTURE_TYPE_I)
2365             skip_bits_long(gb, ctx->cplx_estimation_trash_p);
2366         if (s->pict_type == AV_PICTURE_TYPE_B)
2367             skip_bits_long(gb, ctx->cplx_estimation_trash_b);
2368
2369         if (get_bits_left(gb) < 3) {
2370             av_log(s->avctx, AV_LOG_ERROR, "Header truncated\n");
2371             return AVERROR_INVALIDDATA;
2372         }
2373         ctx->intra_dc_threshold = ff_mpeg4_dc_threshold[get_bits(gb, 3)];
2374         if (!s->progressive_sequence) {
2375             s->top_field_first = get_bits1(gb);
2376             s->alternate_scan  = get_bits1(gb);
2377         } else
2378             s->alternate_scan = 0;
2379     }
2380
2381     if (s->alternate_scan) {
2382         ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable,   ff_alternate_vertical_scan);
2383         ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,   ff_alternate_vertical_scan);
2384         ff_init_scantable(s->idsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
2385         ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2386     } else {
2387         ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable,   ff_zigzag_direct);
2388         ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,   ff_zigzag_direct);
2389         ff_init_scantable(s->idsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
2390         ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2391     }
2392
2393     if (s->pict_type == AV_PICTURE_TYPE_S &&
2394         (ctx->vol_sprite_usage == STATIC_SPRITE ||
2395          ctx->vol_sprite_usage == GMC_SPRITE)) {
2396         if (mpeg4_decode_sprite_trajectory(ctx, gb) < 0)
2397             return AVERROR_INVALIDDATA;
2398         if (ctx->sprite_brightness_change)
2399             av_log(s->avctx, AV_LOG_ERROR,
2400                    "sprite_brightness_change not supported\n");
2401         if (ctx->vol_sprite_usage == STATIC_SPRITE)
2402             av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
2403     }
2404
2405     if (ctx->shape != BIN_ONLY_SHAPE) {
2406         s->chroma_qscale = s->qscale = get_bits(gb, s->quant_precision);
2407         if (s->qscale == 0) {
2408             av_log(s->avctx, AV_LOG_ERROR,
2409                    "Error, header damaged or not MPEG4 header (qscale=0)\n");
2410             return AVERROR_INVALIDDATA;  // makes no sense to continue, as there is nothing left from the image then
2411         }
2412
2413         if (s->pict_type != AV_PICTURE_TYPE_I) {
2414             s->f_code = get_bits(gb, 3);        /* fcode_for */
2415             if (s->f_code == 0) {
2416                 av_log(s->avctx, AV_LOG_ERROR,
2417                        "Error, header damaged or not MPEG4 header (f_code=0)\n");
2418                 s->f_code = 1;
2419                 return AVERROR_INVALIDDATA;  // makes no sense to continue, as there is nothing left from the image then
2420             }
2421         } else
2422             s->f_code = 1;
2423
2424         if (s->pict_type == AV_PICTURE_TYPE_B) {
2425             s->b_code = get_bits(gb, 3);
2426             if (s->b_code == 0) {
2427                 av_log(s->avctx, AV_LOG_ERROR,
2428                        "Error, header damaged or not MPEG4 header (b_code=0)\n");
2429                 s->b_code=1;
2430                 return AVERROR_INVALIDDATA; // makes no sense to continue, as the MV decoding will break very quickly
2431             }
2432         } else
2433             s->b_code = 1;
2434
2435         if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
2436             av_log(s->avctx, AV_LOG_DEBUG,
2437                    "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",
2438                    s->qscale, s->f_code, s->b_code,
2439                    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")),
2440                    gb->size_in_bits,s->progressive_sequence, s->alternate_scan,
2441                    s->top_field_first, s->quarter_sample ? "q" : "h",
2442                    s->data_partitioning, ctx->resync_marker,
2443                    ctx->num_sprite_warping_points, s->sprite_warping_accuracy,
2444                    1 - s->no_rounding, s->vo_type,
2445                    ctx->vol_control_parameters ? " VOLC" : " ", ctx->intra_dc_threshold,
2446                    ctx->cplx_estimation_trash_i, ctx->cplx_estimation_trash_p,
2447                    ctx->cplx_estimation_trash_b,
2448                    s->time,
2449                    time_increment
2450                   );
2451         }
2452
2453         if (!ctx->scalability) {
2454             if (ctx->shape != RECT_SHAPE && s->pict_type != AV_PICTURE_TYPE_I)
2455                 skip_bits1(gb);  // vop shape coding type
2456         } else {
2457             if (ctx->enhancement_type) {
2458                 int load_backward_shape = get_bits1(gb);
2459                 if (load_backward_shape)
2460                     av_log(s->avctx, AV_LOG_ERROR,
2461                            "load backward shape isn't supported\n");
2462             }
2463             skip_bits(gb, 2);  // ref_select_code
2464         }
2465     }
2466     /* detect buggy encoders which don't set the low_delay flag
2467      * (divx4/xvid/opendivx). Note we cannot detect divx5 without b-frames
2468      * easily (although it's buggy too) */
2469     if (s->vo_type == 0 && ctx->vol_control_parameters == 0 &&
2470         ctx->divx_version == -1 && s->picture_number == 0) {
2471         av_log(s->avctx, AV_LOG_WARNING,
2472                "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
2473         s->low_delay = 1;
2474     }
2475
2476     s->picture_number++;  // better than pic number==0 always ;)
2477
2478     // FIXME add short header support
2479     s->y_dc_scale_table = ff_mpeg4_y_dc_scale_table;
2480     s->c_dc_scale_table = ff_mpeg4_c_dc_scale_table;
2481
2482     if (s->workaround_bugs & FF_BUG_EDGE) {
2483         s->h_edge_pos = s->width;
2484         s->v_edge_pos = s->height;
2485     }
2486     return 0;
2487 }
2488
2489 /**
2490  * Decode mpeg4 headers.
2491  * @return <0 if no VOP found (or a damaged one)
2492  *         FRAME_SKIPPED if a not coded VOP is found
2493  *         0 if a VOP is found
2494  */
2495 int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2496 {
2497     MpegEncContext *s = &ctx->m;
2498     unsigned startcode, v;
2499     int ret;
2500
2501     /* search next start code */
2502     align_get_bits(gb);
2503
2504     if (s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630) {
2505         skip_bits(gb, 24);
2506         if (get_bits(gb, 8) == 0xF0)
2507             goto end;
2508     }
2509
2510     startcode = 0xff;
2511     for (;;) {
2512         if (get_bits_count(gb) >= gb->size_in_bits) {
2513             if (gb->size_in_bits == 8 &&
2514                 (ctx->divx_version >= 0 || ctx->xvid_build >= 0) || s->codec_tag == AV_RL32("QMP4")) {
2515                 av_log(s->avctx, AV_LOG_VERBOSE, "frame skip %d\n", gb->size_in_bits);
2516                 return FRAME_SKIPPED;  // divx bug
2517             } else
2518                 return -1;  // end of stream
2519         }
2520
2521         /* use the bits after the test */
2522         v = get_bits(gb, 8);
2523         startcode = ((startcode << 8) | v) & 0xffffffff;
2524
2525         if ((startcode & 0xFFFFFF00) != 0x100)
2526             continue;  // no startcode
2527
2528         if (s->avctx->debug & FF_DEBUG_STARTCODE) {
2529             av_log(s->avctx, AV_LOG_DEBUG, "startcode: %3X ", startcode);
2530             if (startcode <= 0x11F)
2531                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
2532             else if (startcode <= 0x12F)
2533                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
2534             else if (startcode <= 0x13F)
2535                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2536             else if (startcode <= 0x15F)
2537                 av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
2538             else if (startcode <= 0x1AF)
2539                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2540             else if (startcode == 0x1B0)
2541                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
2542             else if (startcode == 0x1B1)
2543                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
2544             else if (startcode == 0x1B2)
2545                 av_log(s->avctx, AV_LOG_DEBUG, "User Data");
2546             else if (startcode == 0x1B3)
2547                 av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
2548             else if (startcode == 0x1B4)
2549                 av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
2550             else if (startcode == 0x1B5)
2551                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
2552             else if (startcode == 0x1B6)
2553                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
2554             else if (startcode == 0x1B7)
2555                 av_log(s->avctx, AV_LOG_DEBUG, "slice start");
2556             else if (startcode == 0x1B8)
2557                 av_log(s->avctx, AV_LOG_DEBUG, "extension start");
2558             else if (startcode == 0x1B9)
2559                 av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
2560             else if (startcode == 0x1BA)
2561                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
2562             else if (startcode == 0x1BB)
2563                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
2564             else if (startcode == 0x1BC)
2565                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
2566             else if (startcode == 0x1BD)
2567                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
2568             else if (startcode == 0x1BE)
2569                 av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
2570             else if (startcode == 0x1BF)
2571                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
2572             else if (startcode == 0x1C0)
2573                 av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
2574             else if (startcode == 0x1C1)
2575                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
2576             else if (startcode == 0x1C2)
2577                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
2578             else if (startcode == 0x1C3)
2579                 av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
2580             else if (startcode <= 0x1C5)
2581                 av_log(s->avctx, AV_LOG_DEBUG, "reserved");
2582             else if (startcode <= 0x1FF)
2583                 av_log(s->avctx, AV_LOG_DEBUG, "System start");
2584             av_log(s->avctx, AV_LOG_DEBUG, " at %d\n", get_bits_count(gb));
2585         }
2586
2587         if (startcode >= 0x120 && startcode <= 0x12F) {
2588             if ((ret = decode_vol_header(ctx, gb)) < 0)
2589                 return ret;
2590         } else if (startcode == USER_DATA_STARTCODE) {
2591             decode_user_data(ctx, gb);
2592         } else if (startcode == GOP_STARTCODE) {
2593             mpeg4_decode_gop_header(s, gb);
2594         } else if (startcode == VOS_STARTCODE) {
2595             mpeg4_decode_profile_level(s, gb);
2596         } else if (startcode == VOP_STARTCODE) {
2597             break;
2598         }
2599
2600         align_get_bits(gb);
2601         startcode = 0xff;
2602     }
2603
2604 end:
2605     if (s->avctx->flags & CODEC_FLAG_LOW_DELAY)
2606         s->low_delay = 1;
2607     s->avctx->has_b_frames = !s->low_delay;
2608
2609     return decode_vop_header(ctx, gb);
2610 }
2611
2612 av_cold void ff_mpeg4videodec_static_init(void) {
2613     static int done = 0;
2614
2615     if (!done) {
2616         ff_rl_init(&ff_mpeg4_rl_intra, ff_mpeg4_static_rl_table_store[0]);
2617         ff_rl_init(&ff_rvlc_rl_inter, ff_mpeg4_static_rl_table_store[1]);
2618         ff_rl_init(&ff_rvlc_rl_intra, ff_mpeg4_static_rl_table_store[2]);
2619         INIT_VLC_RL(ff_mpeg4_rl_intra, 554);
2620         INIT_VLC_RL(ff_rvlc_rl_inter, 1072);
2621         INIT_VLC_RL(ff_rvlc_rl_intra, 1072);
2622         INIT_VLC_STATIC(&dc_lum, DC_VLC_BITS, 10 /* 13 */,
2623                         &ff_mpeg4_DCtab_lum[0][1], 2, 1,
2624                         &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
2625         INIT_VLC_STATIC(&dc_chrom, DC_VLC_BITS, 10 /* 13 */,
2626                         &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
2627                         &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
2628         INIT_VLC_STATIC(&sprite_trajectory, SPRITE_TRAJ_VLC_BITS, 15,
2629                         &ff_sprite_trajectory_tab[0][1], 4, 2,
2630                         &ff_sprite_trajectory_tab[0][0], 4, 2, 128);
2631         INIT_VLC_STATIC(&mb_type_b_vlc, MB_TYPE_B_VLC_BITS, 4,
2632                         &ff_mb_type_b_tab[0][1], 2, 1,
2633                         &ff_mb_type_b_tab[0][0], 2, 1, 16);
2634         done = 1;
2635     }
2636 }
2637
2638 int ff_mpeg4_frame_end(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
2639 {
2640     Mpeg4DecContext *ctx = avctx->priv_data;
2641     MpegEncContext    *s = &ctx->m;
2642
2643     /* divx 5.01+ bitstream reorder stuff */
2644     /* Since this clobbers the input buffer and hwaccel codecs still need the
2645      * data during hwaccel->end_frame we should not do this any earlier */
2646     if (s->divx_packed) {
2647         int current_pos     = s->gb.buffer == s->bitstream_buffer ? 0 : (get_bits_count(&s->gb) >> 3);
2648         int startcode_found = 0;
2649
2650         if (buf_size - current_pos > 7) {
2651
2652             int i;
2653             for (i = current_pos; i < buf_size - 4; i++)
2654
2655                 if (buf[i]     == 0 &&
2656                     buf[i + 1] == 0 &&
2657                     buf[i + 2] == 1 &&
2658                     buf[i + 3] == 0xB6) {
2659                     startcode_found = !(buf[i + 4] & 0x40);
2660                     break;
2661                 }
2662         }
2663
2664         if (startcode_found) {
2665             if (!ctx->showed_packed_warning) {
2666                 av_log(s->avctx, AV_LOG_INFO, "Video uses a non-standard and "
2667                        "wasteful way to store B-frames ('packed B-frames'). "
2668                        "Consider using the mpeg4_unpack_bframes bitstream filter to fix it.\n");
2669                 ctx->showed_packed_warning = 1;
2670             }
2671             av_fast_padded_malloc(&s->bitstream_buffer,
2672                            &s->allocated_bitstream_buffer_size,
2673                            buf_size - current_pos);
2674             if (!s->bitstream_buffer) {
2675                 s->bitstream_buffer_size = 0;
2676                 return AVERROR(ENOMEM);
2677             }
2678             memcpy(s->bitstream_buffer, buf + current_pos,
2679                    buf_size - current_pos);
2680             s->bitstream_buffer_size = buf_size - current_pos;
2681         }
2682     }
2683
2684     return 0;
2685 }
2686
2687 static int mpeg4_update_thread_context(AVCodecContext *dst,
2688                                        const AVCodecContext *src)
2689 {
2690     Mpeg4DecContext *s = dst->priv_data;
2691     const Mpeg4DecContext *s1 = src->priv_data;
2692     int init = s->m.context_initialized;
2693
2694     int ret = ff_mpeg_update_thread_context(dst, src);
2695
2696     if (ret < 0)
2697         return ret;
2698
2699     memcpy(((uint8_t*)s) + sizeof(MpegEncContext), ((uint8_t*)s1) + sizeof(MpegEncContext), sizeof(Mpeg4DecContext) - sizeof(MpegEncContext));
2700
2701     if (CONFIG_MPEG4_DECODER && !init && s1->xvid_build >= 0)
2702         ff_xvid_idct_init(&s->m.idsp, dst);
2703
2704     return 0;
2705 }
2706
2707 static av_cold int decode_init(AVCodecContext *avctx)
2708 {
2709     Mpeg4DecContext *ctx = avctx->priv_data;
2710     MpegEncContext *s = &ctx->m;
2711     int ret;
2712
2713     ctx->divx_version =
2714     ctx->divx_build   =
2715     ctx->xvid_build   =
2716     ctx->lavc_build   = -1;
2717
2718     if ((ret = ff_h263_decode_init(avctx)) < 0)
2719         return ret;
2720
2721     ff_mpeg4videodec_static_init();
2722
2723     s->h263_pred = 1;
2724     s->low_delay = 0; /* default, might be overridden in the vol header during header parsing */
2725     s->decode_mb = mpeg4_decode_mb;
2726     ctx->time_increment_bits = 4; /* default value for broken headers */
2727
2728     avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
2729     avctx->internal->allocate_progress = 1;
2730
2731     return 0;
2732 }
2733
2734 static const AVProfile mpeg4_video_profiles[] = {
2735     { FF_PROFILE_MPEG4_SIMPLE,                    "Simple Profile" },
2736     { FF_PROFILE_MPEG4_SIMPLE_SCALABLE,           "Simple Scalable Profile" },
2737     { FF_PROFILE_MPEG4_CORE,                      "Core Profile" },
2738     { FF_PROFILE_MPEG4_MAIN,                      "Main Profile" },
2739     { FF_PROFILE_MPEG4_N_BIT,                     "N-bit Profile" },
2740     { FF_PROFILE_MPEG4_SCALABLE_TEXTURE,          "Scalable Texture Profile" },
2741     { FF_PROFILE_MPEG4_SIMPLE_FACE_ANIMATION,     "Simple Face Animation Profile" },
2742     { FF_PROFILE_MPEG4_BASIC_ANIMATED_TEXTURE,    "Basic Animated Texture Profile" },
2743     { FF_PROFILE_MPEG4_HYBRID,                    "Hybrid Profile" },
2744     { FF_PROFILE_MPEG4_ADVANCED_REAL_TIME,        "Advanced Real Time Simple Profile" },
2745     { FF_PROFILE_MPEG4_CORE_SCALABLE,             "Code Scalable Profile" },
2746     { FF_PROFILE_MPEG4_ADVANCED_CODING,           "Advanced Coding Profile" },
2747     { FF_PROFILE_MPEG4_ADVANCED_CORE,             "Advanced Core Profile" },
2748     { FF_PROFILE_MPEG4_ADVANCED_SCALABLE_TEXTURE, "Advanced Scalable Texture Profile" },
2749     { FF_PROFILE_MPEG4_SIMPLE_STUDIO,             "Simple Studio Profile" },
2750     { FF_PROFILE_MPEG4_ADVANCED_SIMPLE,           "Advanced Simple Profile" },
2751     { FF_PROFILE_UNKNOWN },
2752 };
2753
2754 static const AVOption mpeg4_options[] = {
2755     {"quarter_sample", "1/4 subpel MC", offsetof(MpegEncContext, quarter_sample), FF_OPT_TYPE_INT, {.i64 = 0}, 0, 1, 0},
2756     {"divx_packed", "divx style packed b frames", offsetof(MpegEncContext, divx_packed), FF_OPT_TYPE_INT, {.i64 = 0}, 0, 1, 0},
2757     {NULL}
2758 };
2759
2760 static const AVClass mpeg4_class = {
2761     "MPEG4 Video Decoder",
2762     av_default_item_name,
2763     mpeg4_options,
2764     LIBAVUTIL_VERSION_INT,
2765 };
2766
2767 AVCodec ff_mpeg4_decoder = {
2768     .name                  = "mpeg4",
2769     .long_name             = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
2770     .type                  = AVMEDIA_TYPE_VIDEO,
2771     .id                    = AV_CODEC_ID_MPEG4,
2772     .priv_data_size        = sizeof(Mpeg4DecContext),
2773     .init                  = decode_init,
2774     .close                 = ff_h263_decode_end,
2775     .decode                = ff_h263_decode_frame,
2776     .capabilities          = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
2777                              CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
2778                              CODEC_CAP_FRAME_THREADS,
2779     .flush                 = ff_mpeg_flush,
2780     .max_lowres            = 3,
2781     .pix_fmts              = ff_h263_hwaccel_pixfmt_list_420,
2782     .profiles              = NULL_IF_CONFIG_SMALL(mpeg4_video_profiles),
2783     .update_thread_context = ONLY_IF_THREADS_ENABLED(mpeg4_update_thread_context),
2784     .priv_class = &mpeg4_class,
2785 };
2786
2787
2788 #if CONFIG_MPEG4_VDPAU_DECODER
2789 static const AVClass mpeg4_vdpau_class = {
2790     "MPEG4 Video VDPAU Decoder",
2791     av_default_item_name,
2792     mpeg4_options,
2793     LIBAVUTIL_VERSION_INT,
2794 };
2795
2796 AVCodec ff_mpeg4_vdpau_decoder = {
2797     .name           = "mpeg4_vdpau",
2798     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),
2799     .type           = AVMEDIA_TYPE_VIDEO,
2800     .id             = AV_CODEC_ID_MPEG4,
2801     .priv_data_size = sizeof(Mpeg4DecContext),
2802     .init           = decode_init,
2803     .close          = ff_h263_decode_end,
2804     .decode         = ff_h263_decode_frame,
2805     .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
2806                       CODEC_CAP_HWACCEL_VDPAU,
2807     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_VDPAU_MPEG4,
2808                                                   AV_PIX_FMT_NONE },
2809     .priv_class     = &mpeg4_vdpau_class,
2810 };
2811 #endif