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   1 /*
   2  * MPEG-4 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/internal.h"
  26 #include "libavutil/opt.h"
  27 #include "error_resilience.h"
  28 #include "idctdsp.h"
  29 #include "internal.h"
  30 #include "mpegutils.h"
  31 #include "mpegvideo.h"
  32 #include "mpegvideodata.h"
  33 #include "mpeg4video.h"
  34 #include "h263.h"
  35 #include "profiles.h"
  36 #include "thread.h"
  37 #include "xvididct.h"
  38
  39 /* The defines below define the number of bits that are read at once for
  40  * reading vlc values. Changing these may improve speed and data cache needs
  41  * be aware though that decreasing them may need the number of stages that is
  42  * passed to get_vlc* to be increased. */
  43 #define SPRITE_TRAJ_VLC_BITS 6
  44 #define DC_VLC_BITS 9
  45 #define MB_TYPE_B_VLC_BITS 4
  46
  47 static VLC dc_lum, dc_chrom;
  48 static VLC sprite_trajectory;
  49 static VLC mb_type_b_vlc;
  50
  51 static const int mb_type_b_map[4] = {
  52     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
  53     MB_TYPE_L0L1    | MB_TYPE_16x16,
  54     MB_TYPE_L1      | MB_TYPE_16x16,
  55     MB_TYPE_L0      | MB_TYPE_16x16,
  56 };
  57
  58 /**
  59  * Predict the ac.
  60  * @param n block index (0-3 are luma, 4-5 are chroma)
  61  * @param dir the ac prediction direction
  62  */
  63 void ff_mpeg4_pred_ac(MpegEncContext *s, int16_t *block, int n, int dir)
  64 {
  65     int i;
  66     int16_t *ac_val, *ac_val1;
  67     int8_t *const qscale_table = s->current_picture.qscale_table;
  68
  69     /* find prediction */
  70     ac_val  = &s->ac_val[0][0][0] + s->block_index[n] * 16;
  71     ac_val1 = ac_val;
  72     if (s->ac_pred) {
  73         if (dir == 0) {
  74             const int xy = s->mb_x - 1 + s->mb_y * s->mb_stride;
  75             /* left prediction */
  76             ac_val -= 16;
  77
  78             if (s->mb_x == 0 || s->qscale == qscale_table[xy] ||
  79                 n == 1 || n == 3) {
  80                 /* same qscale */
  81                 for (i = 1; i < 8; i++)
  82                     block[s->idsp.idct_permutation[i << 3]] += ac_val[i];
  83             } else {
  84                 /* different qscale, we must rescale */
  85                 for (i = 1; i < 8; i++)
  86                     block[s->idsp.idct_permutation[i << 3]] += ROUNDED_DIV(ac_val[i] * qscale_table[xy], s->qscale);
  87             }
  88         } else {
  89             const int xy = s->mb_x + s->mb_y * s->mb_stride - s->mb_stride;
  90             /* top prediction */
  91             ac_val -= 16 * s->block_wrap[n];
  92
  93             if (s->mb_y == 0 || s->qscale == qscale_table[xy] ||
  94                 n == 2 || n == 3) {
  95                 /* same qscale */
  96                 for (i = 1; i < 8; i++)
  97                     block[s->idsp.idct_permutation[i]] += ac_val[i + 8];
  98             } else {
  99                 /* different qscale, we must rescale */
 100                 for (i = 1; i < 8; i++)
 101                     block[s->idsp.idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8] * qscale_table[xy], s->qscale);
 102             }
 103         }
 104     }
 105     /* left copy */
 106     for (i = 1; i < 8; i++)
 107         ac_val1[i] = block[s->idsp.idct_permutation[i << 3]];
 108
 109     /* top copy */
 110     for (i = 1; i < 8; i++)
 111         ac_val1[8 + i] = block[s->idsp.idct_permutation[i]];
 112 }
 113
 114 /**
 115  * check if the next stuff is a resync marker or the end.
 116  * @return 0 if not
 117  */
 118 static inline int mpeg4_is_resync(Mpeg4DecContext *ctx)
 119 {
 120     MpegEncContext *s = &ctx->m;
 121     int bits_count = get_bits_count(&s->gb);
 122     int v          = show_bits(&s->gb, 16);
 123
 124     if (s->workaround_bugs & FF_BUG_NO_PADDING && !ctx->resync_marker)
 125         return 0;
 126
 127     while (v <= 0xFF) {
 128         if (s->pict_type == AV_PICTURE_TYPE_B ||
 129             (v >> (8 - s->pict_type) != 1) || s->partitioned_frame)
 130             break;
 131         skip_bits(&s->gb, 8 + s->pict_type);
 132         bits_count += 8 + s->pict_type;
 133         v = show_bits(&s->gb, 16);
 134     }
 135
 136     if (bits_count + 8 >= s->gb.size_in_bits) {
 137         v >>= 8;
 138         v  |= 0x7F >> (7 - (bits_count & 7));
 139
 140         if (v == 0x7F)
 141             return s->mb_num;
 142     } else {
 143         if (v == ff_mpeg4_resync_prefix[bits_count & 7]) {
 144             int len, mb_num;
 145             int mb_num_bits = av_log2(s->mb_num - 1) + 1;
 146             GetBitContext gb = s->gb;
 147
 148             skip_bits(&s->gb, 1);
 149             align_get_bits(&s->gb);
 150
 151             for (len = 0; len < 32; len++)
 152                 if (get_bits1(&s->gb))
 153                     break;
 154
 155             mb_num = get_bits(&s->gb, mb_num_bits);
 156             if (!mb_num || mb_num > s->mb_num || get_bits_count(&s->gb)+6 > s->gb.size_in_bits)
 157                 mb_num= -1;
 158
 159             s->gb = gb;
 160
 161             if (len >= ff_mpeg4_get_video_packet_prefix_length(s))
 162                 return mb_num;
 163         }
 164     }
 165     return 0;
 166 }
 167
 168 static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *gb)
 169 {
 170     MpegEncContext *s = &ctx->m;
 171     int a     = 2 << s->sprite_warping_accuracy;
 172     int rho   = 3  - s->sprite_warping_accuracy;
 173     int r     = 16 / a;
 174     int alpha = 1;
 175     int beta  = 0;
 176     int w     = s->width;
 177     int h     = s->height;
 178     int min_ab, i, w2, h2, w3, h3;
 179     int sprite_ref[4][2];
 180     int virtual_ref[2][2];
 181     int64_t sprite_offset[2][2];
 182
 183     // only true for rectangle shapes
 184     const int vop_ref[4][2] = { { 0, 0 },         { s->width, 0 },
 185                                 { 0, s->height }, { s->width, s->height } };
 186     int d[4][2]             = { { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } };
 187
 188     if (w <= 0 || h <= 0)
 189         return AVERROR_INVALIDDATA;
 190
 191     for (i = 0; i < ctx->num_sprite_warping_points; i++) {
 192         int length;
 193         int x = 0, y = 0;
 194
 195         length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 196         if (length > 0)
 197             x = get_xbits(gb, length);
 198
 199         if (!(ctx->divx_version == 500 && ctx->divx_build == 413))
 200             check_marker(s->avctx, gb, "before sprite_trajectory");
 201
 202         length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
 203         if (length > 0)
 204             y = get_xbits(gb, length);
 205
 206         check_marker(s->avctx, gb, "after sprite_trajectory");
 207         ctx->sprite_traj[i][0] = d[i][0] = x;
 208         ctx->sprite_traj[i][1] = d[i][1] = y;
 209     }
 210     for (; i < 4; i++)
 211         ctx->sprite_traj[i][0] = ctx->sprite_traj[i][1] = 0;
 212
 213     while ((1 << alpha) < w)
 214         alpha++;
 215     while ((1 << beta) < h)
 216         beta++;  /* typo in the MPEG-4 std for the definition of w' and h' */
 217     w2 = 1 << alpha;
 218     h2 = 1 << beta;
 219
 220     // Note, the 4th point isn't used for GMC
 221     if (ctx->divx_version == 500 && ctx->divx_build == 413) {
 222         sprite_ref[0][0] = a * vop_ref[0][0] + d[0][0];
 223         sprite_ref[0][1] = a * vop_ref[0][1] + d[0][1];
 224         sprite_ref[1][0] = a * vop_ref[1][0] + d[0][0] + d[1][0];
 225         sprite_ref[1][1] = a * vop_ref[1][1] + d[0][1] + d[1][1];
 226         sprite_ref[2][0] = a * vop_ref[2][0] + d[0][0] + d[2][0];
 227         sprite_ref[2][1] = a * vop_ref[2][1] + d[0][1] + d[2][1];
 228     } else {
 229         sprite_ref[0][0] = (a >> 1) * (2 * vop_ref[0][0] + d[0][0]);
 230         sprite_ref[0][1] = (a >> 1) * (2 * vop_ref[0][1] + d[0][1]);
 231         sprite_ref[1][0] = (a >> 1) * (2 * vop_ref[1][0] + d[0][0] + d[1][0]);
 232         sprite_ref[1][1] = (a >> 1) * (2 * vop_ref[1][1] + d[0][1] + d[1][1]);
 233         sprite_ref[2][0] = (a >> 1) * (2 * vop_ref[2][0] + d[0][0] + d[2][0]);
 234         sprite_ref[2][1] = (a >> 1) * (2 * vop_ref[2][1] + d[0][1] + d[2][1]);
 235     }
 236     /* sprite_ref[3][0] = (a >> 1) * (2 * vop_ref[3][0] + d[0][0] + d[1][0] + d[2][0] + d[3][0]);
 237      * sprite_ref[3][1] = (a >> 1) * (2 * vop_ref[3][1] + d[0][1] + d[1][1] + d[2][1] + d[3][1]); */
 238
 239     /* This is mostly identical to the MPEG-4 std (and is totally unreadable
 240      * because of that...). Perhaps it should be reordered to be more readable.
 241      * The idea behind this virtual_ref mess is to be able to use shifts later
 242      * per pixel instead of divides so the distance between points is converted
 243      * from w&h based to w2&h2 based which are of the 2^x form. */
 244     virtual_ref[0][0] = 16 * (vop_ref[0][0] + w2) +
 245                          ROUNDED_DIV(((w - w2) *
 246                                            (r * sprite_ref[0][0] - 16LL * vop_ref[0][0]) +
 247                                       w2 * (r * sprite_ref[1][0] - 16LL * vop_ref[1][0])), w);
 248     virtual_ref[0][1] = 16 * vop_ref[0][1] +
 249                         ROUNDED_DIV(((w - w2) *
 250                                           (r * sprite_ref[0][1] - 16LL * vop_ref[0][1]) +
 251                                      w2 * (r * sprite_ref[1][1] - 16LL * vop_ref[1][1])), w);
 252     virtual_ref[1][0] = 16 * vop_ref[0][0] +
 253                         ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][0] - 16LL * vop_ref[0][0]) +
 254                                            h2 * (r * sprite_ref[2][0] - 16LL * vop_ref[2][0])), h);
 255     virtual_ref[1][1] = 16 * (vop_ref[0][1] + h2) +
 256                         ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][1] - 16LL * vop_ref[0][1]) +
 257                                            h2 * (r * sprite_ref[2][1] - 16LL * vop_ref[2][1])), h);
 258
 259     switch (ctx->num_sprite_warping_points) {
 260     case 0:
 261         sprite_offset[0][0]    =
 262         sprite_offset[0][1]    =
 263         sprite_offset[1][0]    =
 264         sprite_offset[1][1]    = 0;
 265         s->sprite_delta[0][0]  = a;
 266         s->sprite_delta[0][1]  =
 267         s->sprite_delta[1][0]  = 0;
 268         s->sprite_delta[1][1]  = a;
 269         ctx->sprite_shift[0]   =
 270         ctx->sprite_shift[1]   = 0;
 271         break;
 272     case 1:     // GMC only
 273         sprite_offset[0][0]    = sprite_ref[0][0] - a * vop_ref[0][0];
 274         sprite_offset[0][1]    = sprite_ref[0][1] - a * vop_ref[0][1];
 275         sprite_offset[1][0]    = ((sprite_ref[0][0] >> 1) | (sprite_ref[0][0] & 1)) -
 276                                  a * (vop_ref[0][0] / 2);
 277         sprite_offset[1][1]    = ((sprite_ref[0][1] >> 1) | (sprite_ref[0][1] & 1)) -
 278                                  a * (vop_ref[0][1] / 2);
 279         s->sprite_delta[0][0]  = a;
 280         s->sprite_delta[0][1]  =
 281         s->sprite_delta[1][0]  = 0;
 282         s->sprite_delta[1][1]  = a;
 283         ctx->sprite_shift[0]   =
 284         ctx->sprite_shift[1]   = 0;
 285         break;
 286     case 2:
 287         sprite_offset[0][0]    = ((int64_t)      sprite_ref[0][0] * (1 << alpha + rho)) +
 288                                  ((int64_t) -r * sprite_ref[0][0] + virtual_ref[0][0]) *
 289                                  ((int64_t)        -vop_ref[0][0]) +
 290                                  ((int64_t)  r * sprite_ref[0][1] - virtual_ref[0][1]) *
 291                                  ((int64_t)        -vop_ref[0][1]) + (1 << (alpha + rho - 1));
 292         sprite_offset[0][1]    = ((int64_t)      sprite_ref[0][1] * (1 << alpha + rho)) +
 293                                  ((int64_t) -r * sprite_ref[0][1] + virtual_ref[0][1]) *
 294                                  ((int64_t)        -vop_ref[0][0]) +
 295                                  ((int64_t) -r * sprite_ref[0][0] + virtual_ref[0][0]) *
 296                                  ((int64_t)        -vop_ref[0][1]) + (1 << (alpha + rho - 1));
 297         sprite_offset[1][0]    = (((int64_t)-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 298                                   ((int64_t)-2 *    vop_ref[0][0] + 1) +
 299                                   ((int64_t) r * sprite_ref[0][1] - virtual_ref[0][1]) *
 300                                   ((int64_t)-2 *    vop_ref[0][1] + 1) + 2 * w2 * r *
 301                                    (int64_t)     sprite_ref[0][0] - 16 * w2 + (1 << (alpha + rho + 1)));
 302         sprite_offset[1][1]    = (((int64_t)-r * sprite_ref[0][1] + virtual_ref[0][1]) *
 303                                   ((int64_t)-2 *    vop_ref[0][0] + 1) +
 304                                   ((int64_t)-r * sprite_ref[0][0] + virtual_ref[0][0]) *
 305                                   ((int64_t)-2 *    vop_ref[0][1] + 1) + 2 * w2 * r *
 306                                   (int64_t)      sprite_ref[0][1] - 16 * w2 + (1 << (alpha + rho + 1)));
 307         s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
 308         s->sprite_delta[0][1] = (+r * sprite_ref[0][1] - virtual_ref[0][1]);
 309         s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]);
 310         s->sprite_delta[1][1] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
 311
 312         ctx->sprite_shift[0]  = alpha + rho;
 313         ctx->sprite_shift[1]  = alpha + rho + 2;
 314         break;
 315     case 3:
 316         min_ab = FFMIN(alpha, beta);
 317         w3     = w2 >> min_ab;
 318         h3     = h2 >> min_ab;
 319         sprite_offset[0][0]    = ((int64_t)sprite_ref[0][0] * (1 << (alpha + beta + rho - min_ab))) +
 320                                  ((int64_t)-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3 * (-vop_ref[0][0]) +
 321                                  ((int64_t)-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3 * (-vop_ref[0][1]) +
 322                                  ((int64_t)1 << (alpha + beta + rho - min_ab - 1));
 323         sprite_offset[0][1]    = ((int64_t)sprite_ref[0][1] * (1 << (alpha + beta + rho - min_ab))) +
 324                                  ((int64_t)-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3 * (-vop_ref[0][0]) +
 325                                  ((int64_t)-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3 * (-vop_ref[0][1]) +
 326                                  ((int64_t)1 << (alpha + beta + rho - min_ab - 1));
 327         sprite_offset[1][0]    = ((int64_t)-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3 * (-2 * vop_ref[0][0] + 1) +
 328                                  ((int64_t)-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3 * (-2 * vop_ref[0][1] + 1) +
 329                                   (int64_t)2 * w2 * h3 * r * sprite_ref[0][0] - 16 * w2 * h3 +
 330                                  ((int64_t)1 << (alpha + beta + rho - min_ab + 1));
 331         sprite_offset[1][1]    = ((int64_t)-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3 * (-2 * vop_ref[0][0] + 1) +
 332                                  ((int64_t)-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3 * (-2 * vop_ref[0][1] + 1) +
 333                                   (int64_t)2 * w2 * h3 * r * sprite_ref[0][1] - 16 * w2 * h3 +
 334                                  ((int64_t)1 << (alpha + beta + rho - min_ab + 1));
 335         s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3;
 336         s->sprite_delta[0][1] = (-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3;
 337         s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3;
 338         s->sprite_delta[1][1] = (-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3;
 339
 340         ctx->sprite_shift[0]  = alpha + beta + rho - min_ab;
 341         ctx->sprite_shift[1]  = alpha + beta + rho - min_ab + 2;
 342         break;
 343     }
 344     /* try to simplify the situation */
 345     if (s->sprite_delta[0][0] == a << ctx->sprite_shift[0] &&
 346         s->sprite_delta[0][1] == 0 &&
 347         s->sprite_delta[1][0] == 0 &&
 348         s->sprite_delta[1][1] == a << ctx->sprite_shift[0]) {
 349         sprite_offset[0][0] >>= ctx->sprite_shift[0];
 350         sprite_offset[0][1] >>= ctx->sprite_shift[0];
 351         sprite_offset[1][0] >>= ctx->sprite_shift[1];
 352         sprite_offset[1][1] >>= ctx->sprite_shift[1];
 353         s->sprite_delta[0][0] = a;
 354         s->sprite_delta[0][1] = 0;
 355         s->sprite_delta[1][0] = 0;
 356         s->sprite_delta[1][1] = a;
 357         ctx->sprite_shift[0] = 0;
 358         ctx->sprite_shift[1] = 0;
 359         s->real_sprite_warping_points = 1;
 360     } else {
 361         int shift_y = 16 - ctx->sprite_shift[0];
 362         int shift_c = 16 - ctx->sprite_shift[1];
 363
 364         for (i = 0; i < 2; i++) {
 365             if (shift_c < 0 || shift_y < 0 ||
 366                 FFABS(  sprite_offset[0][i]) >= INT_MAX >> shift_y  ||
 367                 FFABS(  sprite_offset[1][i]) >= INT_MAX >> shift_c  ||
 368                 FFABS(s->sprite_delta[0][i]) >= INT_MAX >> shift_y  ||
 369                 FFABS(s->sprite_delta[1][i]) >= INT_MAX >> shift_y
 370             ) {
 371                 avpriv_request_sample(s->avctx, "Too large sprite shift, delta or offset");
 372                 goto overflow;
 373             }
 374         }
 375
 376         for (i = 0; i < 2; i++) {
 377             sprite_offset[0][i]    *= 1 << shift_y;
 378             sprite_offset[1][i]    *= 1 << shift_c;
 379             s->sprite_delta[0][i]  *= 1 << shift_y;
 380             s->sprite_delta[1][i]  *= 1 << shift_y;
 381             ctx->sprite_shift[i]     = 16;
 382
 383         }
 384         for (i = 0; i < 2; i++) {
 385             int64_t sd[2] = {
 386                 s->sprite_delta[i][0] - a * (1LL<<16),
 387                 s->sprite_delta[i][1] - a * (1LL<<16)
 388             };
 389
 390             if (llabs(sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL)) >= INT_MAX ||
 391                 llabs(sprite_offset[0][i] + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX ||
 392                 llabs(sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL) + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX ||
 393                 llabs(s->sprite_delta[i][0] * (w+16LL)) >= INT_MAX ||
 394                 llabs(s->sprite_delta[i][1] * (w+16LL)) >= INT_MAX ||
 395                 llabs(sd[0]) >= INT_MAX ||
 396                 llabs(sd[1]) >= INT_MAX ||
 397                 llabs(sprite_offset[0][i] + sd[0] * (w+16LL)) >= INT_MAX ||
 398                 llabs(sprite_offset[0][i] + sd[1] * (h+16LL)) >= INT_MAX ||
 399                 llabs(sprite_offset[0][i] + sd[0] * (w+16LL) + sd[1] * (h+16LL)) >= INT_MAX
 400             ) {
 401                 avpriv_request_sample(s->avctx, "Overflow on sprite points");
 402                 goto overflow;
 403             }
 404         }
 405         s->real_sprite_warping_points = ctx->num_sprite_warping_points;
 406     }
 407
 408     s->sprite_offset[0][0] = sprite_offset[0][0];
 409     s->sprite_offset[0][1] = sprite_offset[0][1];
 410     s->sprite_offset[1][0] = sprite_offset[1][0];
 411     s->sprite_offset[1][1] = sprite_offset[1][1];
 412
 413     return 0;
 414 overflow:
 415     memset(s->sprite_offset, 0, sizeof(s->sprite_offset));
 416     memset(s->sprite_delta, 0, sizeof(s->sprite_delta));
 417     return AVERROR_PATCHWELCOME;
 418 }
 419
 420 static int decode_new_pred(Mpeg4DecContext *ctx, GetBitContext *gb) {
 421     MpegEncContext *s = &ctx->m;
 422     int len = FFMIN(ctx->time_increment_bits + 3, 15);
 423
 424     get_bits(gb, len);
 425     if (get_bits1(gb))
 426         get_bits(gb, len);
 427     check_marker(s->avctx, gb, "after new_pred");
 428
 429     return 0;
 430 }
 431
 432 /**
 433  * Decode the next video packet.
 434  * @return <0 if something went wrong
 435  */
 436 int ff_mpeg4_decode_video_packet_header(Mpeg4DecContext *ctx)
 437 {
 438     MpegEncContext *s = &ctx->m;
 439
 440     int mb_num_bits      = av_log2(s->mb_num - 1) + 1;
 441     int header_extension = 0, mb_num, len;
 442
 443     /* is there enough space left for a video packet + header */
 444     if (get_bits_count(&s->gb) > s->gb.size_in_bits - 20)
 445         return -1;
 446
 447     for (len = 0; len < 32; len++)
 448         if (get_bits1(&s->gb))
 449             break;
 450
 451     if (len != ff_mpeg4_get_video_packet_prefix_length(s)) {
 452         av_log(s->avctx, AV_LOG_ERROR, "marker does not match f_code\n");
 453         return -1;
 454     }
 455
 456     if (ctx->shape != RECT_SHAPE) {
 457         header_extension = get_bits1(&s->gb);
 458         // FIXME more stuff here
 459     }
 460
 461     mb_num = get_bits(&s->gb, mb_num_bits);
 462     if (mb_num >= s->mb_num) {
 463         av_log(s->avctx, AV_LOG_ERROR,
 464                "illegal mb_num in video packet (%d %d) \n", mb_num, s->mb_num);
 465         return -1;
 466     }
 467
 468     s->mb_x = mb_num % s->mb_width;
 469     s->mb_y = mb_num / s->mb_width;
 470
 471     if (ctx->shape != BIN_ONLY_SHAPE) {
 472         int qscale = get_bits(&s->gb, s->quant_precision);
 473         if (qscale)
 474             s->chroma_qscale = s->qscale = qscale;
 475     }
 476
 477     if (ctx->shape == RECT_SHAPE)
 478         header_extension = get_bits1(&s->gb);
 479
 480     if (header_extension) {
 481         int time_incr = 0;
 482
 483         while (get_bits1(&s->gb) != 0)
 484             time_incr++;
 485
 486         check_marker(s->avctx, &s->gb, "before time_increment in video packed header");
 487         skip_bits(&s->gb, ctx->time_increment_bits);      /* time_increment */
 488         check_marker(s->avctx, &s->gb, "before vop_coding_type in video packed header");
 489
 490         skip_bits(&s->gb, 2); /* vop coding type */
 491         // FIXME not rect stuff here
 492
 493         if (ctx->shape != BIN_ONLY_SHAPE) {
 494             skip_bits(&s->gb, 3); /* intra dc vlc threshold */
 495             // FIXME don't just ignore everything
 496             if (s->pict_type == AV_PICTURE_TYPE_S &&
 497                 ctx->vol_sprite_usage == GMC_SPRITE) {
 498                 if (mpeg4_decode_sprite_trajectory(ctx, &s->gb) < 0)
 499                     return AVERROR_INVALIDDATA;
 500                 av_log(s->avctx, AV_LOG_ERROR, "untested\n");
 501             }
 502
 503             // FIXME reduced res stuff here
 504
 505             if (s->pict_type != AV_PICTURE_TYPE_I) {
 506                 int f_code = get_bits(&s->gb, 3);       /* fcode_for */
 507                 if (f_code == 0)
 508                     av_log(s->avctx, AV_LOG_ERROR,
 509                            "Error, video packet header damaged (f_code=0)\n");
 510             }
 511             if (s->pict_type == AV_PICTURE_TYPE_B) {
 512                 int b_code = get_bits(&s->gb, 3);
 513                 if (b_code == 0)
 514                     av_log(s->avctx, AV_LOG_ERROR,
 515                            "Error, video packet header damaged (b_code=0)\n");
 516             }
 517         }
 518     }
 519     if (ctx->new_pred)
 520         decode_new_pred(ctx, &s->gb);
 521
 522     return 0;
 523 }
 524
 525 /**
 526  * Get the average motion vector for a GMC MB.
 527  * @param n either 0 for the x component or 1 for y
 528  * @return the average MV for a GMC MB
 529  */
 530 static inline int get_amv(Mpeg4DecContext *ctx, int n)
 531 {
 532     MpegEncContext *s = &ctx->m;
 533     int x, y, mb_v, sum, dx, dy, shift;
 534     int len     = 1 << (s->f_code + 4);
 535     const int a = s->sprite_warping_accuracy;
 536
 537     if (s->workaround_bugs & FF_BUG_AMV)
 538         len >>= s->quarter_sample;
 539
 540     if (s->real_sprite_warping_points == 1) {
 541         if (ctx->divx_version == 500 && ctx->divx_build == 413)
 542             sum = s->sprite_offset[0][n] / (1 << (a - s->quarter_sample));
 543         else
 544             sum = RSHIFT(s->sprite_offset[0][n] * (1 << s->quarter_sample), a);
 545     } else {
 546         dx    = s->sprite_delta[n][0];
 547         dy    = s->sprite_delta[n][1];
 548         shift = ctx->sprite_shift[0];
 549         if (n)
 550             dy -= 1 << (shift + a + 1);
 551         else
 552             dx -= 1 << (shift + a + 1);
 553         mb_v = s->sprite_offset[0][n] + dx * s->mb_x * 16 + dy * s->mb_y * 16;
 554
 555         sum = 0;
 556         for (y = 0; y < 16; y++) {
 557             int v;
 558
 559             v = mb_v + dy * y;
 560             // FIXME optimize
 561             for (x = 0; x < 16; x++) {
 562                 sum += v >> shift;
 563                 v   += dx;
 564             }
 565         }
 566         sum = RSHIFT(sum, a + 8 - s->quarter_sample);
 567     }
 568
 569     if (sum < -len)
 570         sum = -len;
 571     else if (sum >= len)
 572         sum = len - 1;
 573
 574     return sum;
 575 }
 576
 577 /**
 578  * Decode the dc value.
 579  * @param n block index (0-3 are luma, 4-5 are chroma)
 580  * @param dir_ptr the prediction direction will be stored here
 581  * @return the quantized dc
 582  */
 583 static inline int mpeg4_decode_dc(MpegEncContext *s, int n, int *dir_ptr)
 584 {
 585     int level, code;
 586
 587     if (n < 4)
 588         code = get_vlc2(&s->gb, dc_lum.table, DC_VLC_BITS, 1);
 589     else
 590         code = get_vlc2(&s->gb, dc_chrom.table, DC_VLC_BITS, 1);
 591
 592     if (code < 0 || code > 9 /* && s->nbit < 9 */) {
 593         av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
 594         return -1;
 595     }
 596
 597     if (code == 0) {
 598         level = 0;
 599     } else {
 600         if (IS_3IV1) {
 601             if (code == 1)
 602                 level = 2 * get_bits1(&s->gb) - 1;
 603             else {
 604                 if (get_bits1(&s->gb))
 605                     level = get_bits(&s->gb, code - 1) + (1 << (code - 1));
 606                 else
 607                     level = -get_bits(&s->gb, code - 1) - (1 << (code - 1));
 608             }
 609         } else {
 610             level = get_xbits(&s->gb, code);
 611         }
 612
 613         if (code > 8) {
 614             if (get_bits1(&s->gb) == 0) { /* marker */
 615                 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT)) {
 616                     av_log(s->avctx, AV_LOG_ERROR, "dc marker bit missing\n");
 617                     return -1;
 618                 }
 619             }
 620         }
 621     }
 622
 623     return ff_mpeg4_pred_dc(s, n, level, dir_ptr, 0);
 624 }
 625
 626 /**
 627  * Decode first partition.
 628  * @return number of MBs decoded or <0 if an error occurred
 629  */
 630 static int mpeg4_decode_partition_a(Mpeg4DecContext *ctx)
 631 {
 632     MpegEncContext *s = &ctx->m;
 633     int mb_num = 0;
 634     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 635
 636     /* decode first partition */
 637     s->first_slice_line = 1;
 638     for (; s->mb_y < s->mb_height; s->mb_y++) {
 639         ff_init_block_index(s);
 640         for (; s->mb_x < s->mb_width; s->mb_x++) {
 641             const int xy = s->mb_x + s->mb_y * s->mb_stride;
 642             int cbpc;
 643             int dir = 0;
 644
 645             mb_num++;
 646             ff_update_block_index(s);
 647             if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
 648                 s->first_slice_line = 0;
 649
 650             if (s->pict_type == AV_PICTURE_TYPE_I) {
 651                 int i;
 652
 653                 do {
 654                     if (show_bits_long(&s->gb, 19) == DC_MARKER)
 655                         return mb_num - 1;
 656
 657                     cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 658                     if (cbpc < 0) {
 659                         av_log(s->avctx, AV_LOG_ERROR,
 660                                "mcbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 661                         return -1;
 662                     }
 663                 } while (cbpc == 8);
 664
 665                 s->cbp_table[xy]               = cbpc & 3;
 666                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 667                 s->mb_intra                    = 1;
 668
 669                 if (cbpc & 4)
 670                     ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 671
 672                 s->current_picture.qscale_table[xy] = s->qscale;
 673
 674                 s->mbintra_table[xy] = 1;
 675                 for (i = 0; i < 6; i++) {
 676                     int dc_pred_dir;
 677                     int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
 678                     if (dc < 0) {
 679                         av_log(s->avctx, AV_LOG_ERROR,
 680                                "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 681                         return -1;
 682                     }
 683                     dir <<= 1;
 684                     if (dc_pred_dir)
 685                         dir |= 1;
 686                 }
 687                 s->pred_dir_table[xy] = dir;
 688             } else { /* P/S_TYPE */
 689                 int mx, my, pred_x, pred_y, bits;
 690                 int16_t *const mot_val = s->current_picture.motion_val[0][s->block_index[0]];
 691                 const int stride       = s->b8_stride * 2;
 692
 693 try_again:
 694                 bits = show_bits(&s->gb, 17);
 695                 if (bits == MOTION_MARKER)
 696                     return mb_num - 1;
 697
 698                 skip_bits1(&s->gb);
 699                 if (bits & 0x10000) {
 700                     /* skip mb */
 701                     if (s->pict_type == AV_PICTURE_TYPE_S &&
 702                         ctx->vol_sprite_usage == GMC_SPRITE) {
 703                         s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
 704                                                          MB_TYPE_16x16 |
 705                                                          MB_TYPE_GMC   |
 706                                                          MB_TYPE_L0;
 707                         mx = get_amv(ctx, 0);
 708                         my = get_amv(ctx, 1);
 709                     } else {
 710                         s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
 711                                                          MB_TYPE_16x16 |
 712                                                          MB_TYPE_L0;
 713                         mx = my = 0;
 714                     }
 715                     mot_val[0]          =
 716                     mot_val[2]          =
 717                     mot_val[0 + stride] =
 718                     mot_val[2 + stride] = mx;
 719                     mot_val[1]          =
 720                     mot_val[3]          =
 721                     mot_val[1 + stride] =
 722                     mot_val[3 + stride] = my;
 723
 724                     if (s->mbintra_table[xy])
 725                         ff_clean_intra_table_entries(s);
 726                     continue;
 727                 }
 728
 729                 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 730                 if (cbpc < 0) {
 731                     av_log(s->avctx, AV_LOG_ERROR,
 732                            "mcbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
 733                     return -1;
 734                 }
 735                 if (cbpc == 20)
 736                     goto try_again;
 737
 738                 s->cbp_table[xy] = cbpc & (8 + 3);  // 8 is dquant
 739
 740                 s->mb_intra = ((cbpc & 4) != 0);
 741
 742                 if (s->mb_intra) {
 743                     s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 744                     s->mbintra_table[xy] = 1;
 745                     mot_val[0]          =
 746                     mot_val[2]          =
 747                     mot_val[0 + stride] =
 748                     mot_val[2 + stride] = 0;
 749                     mot_val[1]          =
 750                     mot_val[3]          =
 751                     mot_val[1 + stride] =
 752                     mot_val[3 + stride] = 0;
 753                 } else {
 754                     if (s->mbintra_table[xy])
 755                         ff_clean_intra_table_entries(s);
 756
 757                     if (s->pict_type == AV_PICTURE_TYPE_S &&
 758                         ctx->vol_sprite_usage == GMC_SPRITE &&
 759                         (cbpc & 16) == 0)
 760                         s->mcsel = get_bits1(&s->gb);
 761                     else
 762                         s->mcsel = 0;
 763
 764                     if ((cbpc & 16) == 0) {
 765                         /* 16x16 motion prediction */
 766
 767                         ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 768                         if (!s->mcsel) {
 769                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
 770                             if (mx >= 0xffff)
 771                                 return -1;
 772
 773                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
 774                             if (my >= 0xffff)
 775                                 return -1;
 776                             s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
 777                                                              MB_TYPE_L0;
 778                         } else {
 779                             mx = get_amv(ctx, 0);
 780                             my = get_amv(ctx, 1);
 781                             s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
 782                                                              MB_TYPE_GMC   |
 783                                                              MB_TYPE_L0;
 784                         }
 785
 786                         mot_val[0]          =
 787                         mot_val[2]          =
 788                         mot_val[0 + stride] =
 789                         mot_val[2 + stride] = mx;
 790                         mot_val[1]          =
 791                         mot_val[3]          =
 792                         mot_val[1 + stride] =
 793                         mot_val[3 + stride] = my;
 794                     } else {
 795                         int i;
 796                         s->current_picture.mb_type[xy] = MB_TYPE_8x8 |
 797                                                          MB_TYPE_L0;
 798                         for (i = 0; i < 4; i++) {
 799                             int16_t *mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 800                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
 801                             if (mx >= 0xffff)
 802                                 return -1;
 803
 804                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
 805                             if (my >= 0xffff)
 806                                 return -1;
 807                             mot_val[0] = mx;
 808                             mot_val[1] = my;
 809                         }
 810                     }
 811                 }
 812             }
 813         }
 814         s->mb_x = 0;
 815     }
 816
 817     return mb_num;
 818 }
 819
 820 /**
 821  * decode second partition.
 822  * @return <0 if an error occurred
 823  */
 824 static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count)
 825 {
 826     int mb_num = 0;
 827     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 828
 829     s->mb_x = s->resync_mb_x;
 830     s->first_slice_line = 1;
 831     for (s->mb_y = s->resync_mb_y; mb_num < mb_count; s->mb_y++) {
 832         ff_init_block_index(s);
 833         for (; mb_num < mb_count && s->mb_x < s->mb_width; s->mb_x++) {
 834             const int xy = s->mb_x + s->mb_y * s->mb_stride;
 835
 836             mb_num++;
 837             ff_update_block_index(s);
 838             if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
 839                 s->first_slice_line = 0;
 840
 841             if (s->pict_type == AV_PICTURE_TYPE_I) {
 842                 int ac_pred = get_bits1(&s->gb);
 843                 int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 844                 if (cbpy < 0) {
 845                     av_log(s->avctx, AV_LOG_ERROR,
 846                            "cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 847                     return -1;
 848                 }
 849
 850                 s->cbp_table[xy]               |= cbpy << 2;
 851                 s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
 852             } else { /* P || S_TYPE */
 853                 if (IS_INTRA(s->current_picture.mb_type[xy])) {
 854                     int i;
 855                     int dir     = 0;
 856                     int ac_pred = get_bits1(&s->gb);
 857                     int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 858
 859                     if (cbpy < 0) {
 860                         av_log(s->avctx, AV_LOG_ERROR,
 861                                "I cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 862                         return -1;
 863                     }
 864
 865                     if (s->cbp_table[xy] & 8)
 866                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 867                     s->current_picture.qscale_table[xy] = s->qscale;
 868
 869                     for (i = 0; i < 6; i++) {
 870                         int dc_pred_dir;
 871                         int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
 872                         if (dc < 0) {
 873                             av_log(s->avctx, AV_LOG_ERROR,
 874                                    "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
 875                             return -1;
 876                         }
 877                         dir <<= 1;
 878                         if (dc_pred_dir)
 879                             dir |= 1;
 880                     }
 881                     s->cbp_table[xy]               &= 3;  // remove dquant
 882                     s->cbp_table[xy]               |= cbpy << 2;
 883                     s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
 884                     s->pred_dir_table[xy]           = dir;
 885                 } else if (IS_SKIP(s->current_picture.mb_type[xy])) {
 886                     s->current_picture.qscale_table[xy] = s->qscale;
 887                     s->cbp_table[xy]                    = 0;
 888                 } else {
 889                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 890
 891                     if (cbpy < 0) {
 892                         av_log(s->avctx, AV_LOG_ERROR,
 893                                "P cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
 894                         return -1;
 895                     }
 896
 897                     if (s->cbp_table[xy] & 8)
 898                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
 899                     s->current_picture.qscale_table[xy] = s->qscale;
 900
 901                     s->cbp_table[xy] &= 3;  // remove dquant
 902                     s->cbp_table[xy] |= (cbpy ^ 0xf) << 2;
 903                 }
 904             }
 905         }
 906         if (mb_num >= mb_count)
 907             return 0;
 908         s->mb_x = 0;
 909     }
 910     return 0;
 911 }
 912
 913 /**
 914  * Decode the first and second partition.
 915  * @return <0 if error (and sets error type in the error_status_table)
 916  */
 917 int ff_mpeg4_decode_partitions(Mpeg4DecContext *ctx)
 918 {
 919     MpegEncContext *s = &ctx->m;
 920     int mb_num;
 921     const int part_a_error = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_ERROR | ER_MV_ERROR) : ER_MV_ERROR;
 922     const int part_a_end   = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_END   | ER_MV_END)   : ER_MV_END;
 923
 924     mb_num = mpeg4_decode_partition_a(ctx);
 925     if (mb_num <= 0) {
 926         ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 927                         s->mb_x, s->mb_y, part_a_error);
 928         return -1;
 929     }
 930
 931     if (s->resync_mb_x + s->resync_mb_y * s->mb_width + mb_num > s->mb_num) {
 932         av_log(s->avctx, AV_LOG_ERROR, "slice below monitor ...\n");
 933         ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 934                         s->mb_x, s->mb_y, part_a_error);
 935         return -1;
 936     }
 937
 938     s->mb_num_left = mb_num;
 939
 940     if (s->pict_type == AV_PICTURE_TYPE_I) {
 941         while (show_bits(&s->gb, 9) == 1)
 942             skip_bits(&s->gb, 9);
 943         if (get_bits_long(&s->gb, 19) != DC_MARKER) {
 944             av_log(s->avctx, AV_LOG_ERROR,
 945                    "marker missing after first I partition at %d %d\n",
 946                    s->mb_x, s->mb_y);
 947             return -1;
 948         }
 949     } else {
 950         while (show_bits(&s->gb, 10) == 1)
 951             skip_bits(&s->gb, 10);
 952         if (get_bits(&s->gb, 17) != MOTION_MARKER) {
 953             av_log(s->avctx, AV_LOG_ERROR,
 954                    "marker missing after first P partition at %d %d\n",
 955                    s->mb_x, s->mb_y);
 956             return -1;
 957         }
 958     }
 959     ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 960                     s->mb_x - 1, s->mb_y, part_a_end);
 961
 962     if (mpeg4_decode_partition_b(s, mb_num) < 0) {
 963         if (s->pict_type == AV_PICTURE_TYPE_P)
 964             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 965                             s->mb_x, s->mb_y, ER_DC_ERROR);
 966         return -1;
 967     } else {
 968         if (s->pict_type == AV_PICTURE_TYPE_P)
 969             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
 970                             s->mb_x - 1, s->mb_y, ER_DC_END);
 971     }
 972
 973     return 0;
 974 }
 975
 976 /**
 977  * Decode a block.
 978  * @return <0 if an error occurred
 979  */
 980 static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
 981                                      int n, int coded, int intra, int rvlc)
 982 {
 983     MpegEncContext *s = &ctx->m;
 984     int level, i, last, run, qmul, qadd;
 985     int av_uninit(dc_pred_dir);
 986     RLTable *rl;
 987     RL_VLC_ELEM *rl_vlc;
 988     const uint8_t *scan_table;
 989
 990     // Note intra & rvlc should be optimized away if this is inlined
 991
 992     if (intra) {
 993         if (ctx->use_intra_dc_vlc) {
 994             /* DC coef */
 995             if (s->partitioned_frame) {
 996                 level = s->dc_val[0][s->block_index[n]];
 997                 if (n < 4)
 998                     level = FASTDIV((level + (s->y_dc_scale >> 1)), s->y_dc_scale);
 999                 else
1000                     level = FASTDIV((level + (s->c_dc_scale >> 1)), s->c_dc_scale);
1001                 dc_pred_dir = (s->pred_dir_table[s->mb_x + s->mb_y * s->mb_stride] << n) & 32;
1002             } else {
1003                 level = mpeg4_decode_dc(s, n, &dc_pred_dir);
1004                 if (level < 0)
1005                     return -1;
1006             }
1007             block[0] = level;
1008             i        = 0;
1009         } else {
1010             i = -1;
1011             ff_mpeg4_pred_dc(s, n, 0, &dc_pred_dir, 0);
1012         }
1013         if (!coded)
1014             goto not_coded;
1015
1016         if (rvlc) {
1017             rl     = &ff_rvlc_rl_intra;
1018             rl_vlc = ff_rvlc_rl_intra.rl_vlc[0];
1019         } else {
1020             rl     = &ff_mpeg4_rl_intra;
1021             rl_vlc = ff_mpeg4_rl_intra.rl_vlc[0];
1022         }
1023         if (s->ac_pred) {
1024             if (dc_pred_dir == 0)
1025                 scan_table = s->intra_v_scantable.permutated;  /* left */
1026             else
1027                 scan_table = s->intra_h_scantable.permutated;  /* top */
1028         } else {
1029             scan_table = s->intra_scantable.permutated;
1030         }
1031         qmul = 1;
1032         qadd = 0;
1033     } else {
1034         i = -1;
1035         if (!coded) {
1036             s->block_last_index[n] = i;
1037             return 0;
1038         }
1039         if (rvlc)
1040             rl = &ff_rvlc_rl_inter;
1041         else
1042             rl = &ff_h263_rl_inter;
1043
1044         scan_table = s->intra_scantable.permutated;
1045
1046         if (s->mpeg_quant) {
1047             qmul = 1;
1048             qadd = 0;
1049             if (rvlc)
1050                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[0];
1051             else
1052                 rl_vlc = ff_h263_rl_inter.rl_vlc[0];
1053         } else {
1054             qmul = s->qscale << 1;
1055             qadd = (s->qscale - 1) | 1;
1056             if (rvlc)
1057                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[s->qscale];
1058             else
1059                 rl_vlc = ff_h263_rl_inter.rl_vlc[s->qscale];
1060         }
1061     }
1062     {
1063         OPEN_READER(re, &s->gb);
1064         for (;;) {
1065             UPDATE_CACHE(re, &s->gb);
1066             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
1067             if (level == 0) {
1068                 /* escape */
1069                 if (rvlc) {
1070                     if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1071                         av_log(s->avctx, AV_LOG_ERROR,
1072                                "1. marker bit missing in rvlc esc\n");
1073                         return -1;
1074                     }
1075                     SKIP_CACHE(re, &s->gb, 1);
1076
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, 1 + 1 + 6);
1081                     UPDATE_CACHE(re, &s->gb);
1082
1083                     if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1084                         av_log(s->avctx, AV_LOG_ERROR,
1085                                "2. marker bit missing in rvlc esc\n");
1086                         return -1;
1087                     }
1088                     SKIP_CACHE(re, &s->gb, 1);
1089
1090                     level = SHOW_UBITS(re, &s->gb, 11);
1091                     SKIP_CACHE(re, &s->gb, 11);
1092
1093                     if (SHOW_UBITS(re, &s->gb, 5) != 0x10) {
1094                         av_log(s->avctx, AV_LOG_ERROR, "reverse esc missing\n");
1095                         return -1;
1096                     }
1097                     SKIP_CACHE(re, &s->gb, 5);
1098
1099                     level = level * qmul + qadd;
1100                     level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1101                     SKIP_COUNTER(re, &s->gb, 1 + 11 + 5 + 1);
1102
1103                     i += run + 1;
1104                     if (last)
1105                         i += 192;
1106                 } else {
1107                     int cache;
1108                     cache = GET_CACHE(re, &s->gb);
1109
1110                     if (IS_3IV1)
1111                         cache ^= 0xC0000000;
1112
1113                     if (cache & 0x80000000) {
1114                         if (cache & 0x40000000) {
1115                             /* third escape */
1116                             SKIP_CACHE(re, &s->gb, 2);
1117                             last = SHOW_UBITS(re, &s->gb, 1);
1118                             SKIP_CACHE(re, &s->gb, 1);
1119                             run = SHOW_UBITS(re, &s->gb, 6);
1120                             SKIP_COUNTER(re, &s->gb, 2 + 1 + 6);
1121                             UPDATE_CACHE(re, &s->gb);
1122
1123                             if (IS_3IV1) {
1124                                 level = SHOW_SBITS(re, &s->gb, 12);
1125                                 LAST_SKIP_BITS(re, &s->gb, 12);
1126                             } else {
1127                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1128                                     av_log(s->avctx, AV_LOG_ERROR,
1129                                            "1. marker bit missing in 3. esc\n");
1130                                     if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR))
1131                                         return -1;
1132                                 }
1133                                 SKIP_CACHE(re, &s->gb, 1);
1134
1135                                 level = SHOW_SBITS(re, &s->gb, 12);
1136                                 SKIP_CACHE(re, &s->gb, 12);
1137
1138                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1139                                     av_log(s->avctx, AV_LOG_ERROR,
1140                                            "2. marker bit missing in 3. esc\n");
1141                                     if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR))
1142                                         return -1;
1143                                 }
1144
1145                                 SKIP_COUNTER(re, &s->gb, 1 + 12 + 1);
1146                             }
1147
1148 #if 0
1149                             if (s->error_recognition >= FF_ER_COMPLIANT) {
1150                                 const int abs_level= FFABS(level);
1151                                 if (abs_level<=MAX_LEVEL && run<=MAX_RUN) {
1152                                     const int run1= run - rl->max_run[last][abs_level] - 1;
1153                                     if (abs_level <= rl->max_level[last][run]) {
1154                                         av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, vlc encoding possible\n");
1155                                         return -1;
1156                                     }
1157                                     if (s->error_recognition > FF_ER_COMPLIANT) {
1158                                         if (abs_level <= rl->max_level[last][run]*2) {
1159                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 1 encoding possible\n");
1160                                             return -1;
1161                                         }
1162                                         if (run1 >= 0 && abs_level <= rl->max_level[last][run1]) {
1163                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 2 encoding possible\n");
1164                                             return -1;
1165                                         }
1166                                     }
1167                                 }
1168                             }
1169 #endif
1170                             if (level > 0)
1171                                 level = level * qmul + qadd;
1172                             else
1173                                 level = level * qmul - qadd;
1174
1175                             if ((unsigned)(level + 2048) > 4095) {
1176                                 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_AGGRESSIVE)) {
1177                                     if (level > 2560 || level < -2560) {
1178                                         av_log(s->avctx, AV_LOG_ERROR,
1179                                                "|level| overflow in 3. esc, qp=%d\n",
1180                                                s->qscale);
1181                                         return -1;
1182                                     }
1183                                 }
1184                                 level = level < 0 ? -2048 : 2047;
1185                             }
1186
1187                             i += run + 1;
1188                             if (last)
1189                                 i += 192;
1190                         } else {
1191                             /* second escape */
1192                             SKIP_BITS(re, &s->gb, 2);
1193                             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1194                             i    += run + rl->max_run[run >> 7][level / qmul] + 1;  // FIXME opt indexing
1195                             level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1196                             LAST_SKIP_BITS(re, &s->gb, 1);
1197                         }
1198                     } else {
1199                         /* first escape */
1200                         SKIP_BITS(re, &s->gb, 1);
1201                         GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1202                         i    += run;
1203                         level = level + rl->max_level[run >> 7][(run - 1) & 63] * qmul;  // FIXME opt indexing
1204                         level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1205                         LAST_SKIP_BITS(re, &s->gb, 1);
1206                     }
1207                 }
1208             } else {
1209                 i    += run;
1210                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1211                 LAST_SKIP_BITS(re, &s->gb, 1);
1212             }
1213             ff_tlog(s->avctx, "dct[%d][%d] = %- 4d end?:%d\n", scan_table[i&63]&7, scan_table[i&63] >> 3, level, i>62);
1214             if (i > 62) {
1215                 i -= 192;
1216                 if (i & (~63)) {
1217                     av_log(s->avctx, AV_LOG_ERROR,
1218                            "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1219                     return -1;
1220                 }
1221
1222                 block[scan_table[i]] = level;
1223                 break;
1224             }
1225
1226             block[scan_table[i]] = level;
1227         }
1228         CLOSE_READER(re, &s->gb);
1229     }
1230
1231 not_coded:
1232     if (intra) {
1233         if (!ctx->use_intra_dc_vlc) {
1234             block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0);
1235
1236             i -= i >> 31;  // if (i == -1) i = 0;
1237         }
1238
1239         ff_mpeg4_pred_ac(s, block, n, dc_pred_dir);
1240         if (s->ac_pred)
1241             i = 63;  // FIXME not optimal
1242     }
1243     s->block_last_index[n] = i;
1244     return 0;
1245 }
1246
1247 /**
1248  * decode partition C of one MB.
1249  * @return <0 if an error occurred
1250  */
1251 static int mpeg4_decode_partitioned_mb(MpegEncContext *s, int16_t block[6][64])
1252 {
1253     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1254     int cbp, mb_type;
1255     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1256
1257     mb_type = s->current_picture.mb_type[xy];
1258     cbp     = s->cbp_table[xy];
1259
1260     ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1261
1262     if (s->current_picture.qscale_table[xy] != s->qscale)
1263         ff_set_qscale(s, s->current_picture.qscale_table[xy]);
1264
1265     if (s->pict_type == AV_PICTURE_TYPE_P ||
1266         s->pict_type == AV_PICTURE_TYPE_S) {
1267         int i;
1268         for (i = 0; i < 4; i++) {
1269             s->mv[0][i][0] = s->current_picture.motion_val[0][s->block_index[i]][0];
1270             s->mv[0][i][1] = s->current_picture.motion_val[0][s->block_index[i]][1];
1271         }
1272         s->mb_intra = IS_INTRA(mb_type);
1273
1274         if (IS_SKIP(mb_type)) {
1275             /* skip mb */
1276             for (i = 0; i < 6; i++)
1277                 s->block_last_index[i] = -1;
1278             s->mv_dir  = MV_DIR_FORWARD;
1279             s->mv_type = MV_TYPE_16X16;
1280             if (s->pict_type == AV_PICTURE_TYPE_S
1281                 && ctx->vol_sprite_usage == GMC_SPRITE) {
1282                 s->mcsel      = 1;
1283                 s->mb_skipped = 0;
1284             } else {
1285                 s->mcsel      = 0;
1286                 s->mb_skipped = 1;
1287             }
1288         } else if (s->mb_intra) {
1289             s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1290         } else if (!s->mb_intra) {
1291             // s->mcsel = 0;  // FIXME do we need to init that?
1292
1293             s->mv_dir = MV_DIR_FORWARD;
1294             if (IS_8X8(mb_type)) {
1295                 s->mv_type = MV_TYPE_8X8;
1296             } else {
1297                 s->mv_type = MV_TYPE_16X16;
1298             }
1299         }
1300     } else { /* I-Frame */
1301         s->mb_intra = 1;
1302         s->ac_pred  = IS_ACPRED(s->current_picture.mb_type[xy]);
1303     }
1304
1305     if (!IS_SKIP(mb_type)) {
1306         int i;
1307         s->bdsp.clear_blocks(s->block[0]);
1308         /* decode each block */
1309         for (i = 0; i < 6; i++) {
1310             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, s->mb_intra, ctx->rvlc) < 0) {
1311                 av_log(s->avctx, AV_LOG_ERROR,
1312                        "texture corrupted at %d %d %d\n",
1313                        s->mb_x, s->mb_y, s->mb_intra);
1314                 return -1;
1315             }
1316             cbp += cbp;
1317         }
1318     }
1319
1320     /* per-MB end of slice check */
1321     if (--s->mb_num_left <= 0) {
1322         if (mpeg4_is_resync(ctx))
1323             return SLICE_END;
1324         else
1325             return SLICE_NOEND;
1326     } else {
1327         if (mpeg4_is_resync(ctx)) {
1328             const int delta = s->mb_x + 1 == s->mb_width ? 2 : 1;
1329             if (s->cbp_table[xy + delta])
1330                 return SLICE_END;
1331         }
1332         return SLICE_OK;
1333     }
1334 }
1335
1336 static int mpeg4_decode_mb(MpegEncContext *s, int16_t block[6][64])
1337 {
1338     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1339     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
1340     int16_t *mot_val;
1341     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
1342     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1343
1344     av_assert2(s->h263_pred);
1345
1346     if (s->pict_type == AV_PICTURE_TYPE_P ||
1347         s->pict_type == AV_PICTURE_TYPE_S) {
1348         do {
1349             if (get_bits1(&s->gb)) {
1350                 /* skip mb */
1351                 s->mb_intra = 0;
1352                 for (i = 0; i < 6; i++)
1353                     s->block_last_index[i] = -1;
1354                 s->mv_dir  = MV_DIR_FORWARD;
1355                 s->mv_type = MV_TYPE_16X16;
1356                 if (s->pict_type == AV_PICTURE_TYPE_S &&
1357                     ctx->vol_sprite_usage == GMC_SPRITE) {
1358                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1359                                                      MB_TYPE_GMC   |
1360                                                      MB_TYPE_16x16 |
1361                                                      MB_TYPE_L0;
1362                     s->mcsel       = 1;
1363                     s->mv[0][0][0] = get_amv(ctx, 0);
1364                     s->mv[0][0][1] = get_amv(ctx, 1);
1365                     s->mb_skipped  = 0;
1366                 } else {
1367                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1368                                                      MB_TYPE_16x16 |
1369                                                      MB_TYPE_L0;
1370                     s->mcsel       = 0;
1371                     s->mv[0][0][0] = 0;
1372                     s->mv[0][0][1] = 0;
1373                     s->mb_skipped  = 1;
1374                 }
1375                 goto end;
1376             }
1377             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
1378             if (cbpc < 0) {
1379                 av_log(s->avctx, AV_LOG_ERROR,
1380                        "mcbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1381                 return -1;
1382             }
1383         } while (cbpc == 20);
1384
1385         s->bdsp.clear_blocks(s->block[0]);
1386         dquant      = cbpc & 8;
1387         s->mb_intra = ((cbpc & 4) != 0);
1388         if (s->mb_intra)
1389             goto intra;
1390
1391         if (s->pict_type == AV_PICTURE_TYPE_S &&
1392             ctx->vol_sprite_usage == GMC_SPRITE && (cbpc & 16) == 0)
1393             s->mcsel = get_bits1(&s->gb);
1394         else
1395             s->mcsel = 0;
1396         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1) ^ 0x0F;
1397         if (cbpy < 0) {
1398             av_log(s->avctx, AV_LOG_ERROR,
1399                    "P cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
1400             return AVERROR_INVALIDDATA;
1401         }
1402
1403         cbp = (cbpc & 3) | (cbpy << 2);
1404         if (dquant)
1405             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1406         if ((!s->progressive_sequence) &&
1407             (cbp || (s->workaround_bugs & FF_BUG_XVID_ILACE)))
1408             s->interlaced_dct = get_bits1(&s->gb);
1409
1410         s->mv_dir = MV_DIR_FORWARD;
1411         if ((cbpc & 16) == 0) {
1412             if (s->mcsel) {
1413                 s->current_picture.mb_type[xy] = MB_TYPE_GMC   |
1414                                                  MB_TYPE_16x16 |
1415                                                  MB_TYPE_L0;
1416                 /* 16x16 global motion prediction */
1417                 s->mv_type     = MV_TYPE_16X16;
1418                 mx             = get_amv(ctx, 0);
1419                 my             = get_amv(ctx, 1);
1420                 s->mv[0][0][0] = mx;
1421                 s->mv[0][0][1] = my;
1422             } else if ((!s->progressive_sequence) && get_bits1(&s->gb)) {
1423                 s->current_picture.mb_type[xy] = MB_TYPE_16x8 |
1424                                                  MB_TYPE_L0   |
1425                                                  MB_TYPE_INTERLACED;
1426                 /* 16x8 field motion prediction */
1427                 s->mv_type = MV_TYPE_FIELD;
1428
1429                 s->field_select[0][0] = get_bits1(&s->gb);
1430                 s->field_select[0][1] = get_bits1(&s->gb);
1431
1432                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1433
1434                 for (i = 0; i < 2; i++) {
1435                     mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1436                     if (mx >= 0xffff)
1437                         return -1;
1438
1439                     my = ff_h263_decode_motion(s, pred_y / 2, s->f_code);
1440                     if (my >= 0xffff)
1441                         return -1;
1442
1443                     s->mv[0][i][0] = mx;
1444                     s->mv[0][i][1] = my;
1445                 }
1446             } else {
1447                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
1448                 /* 16x16 motion prediction */
1449                 s->mv_type = MV_TYPE_16X16;
1450                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1451                 mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1452
1453                 if (mx >= 0xffff)
1454                     return -1;
1455
1456                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1457
1458                 if (my >= 0xffff)
1459                     return -1;
1460                 s->mv[0][0][0] = mx;
1461                 s->mv[0][0][1] = my;
1462             }
1463         } else {
1464             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
1465             s->mv_type                     = MV_TYPE_8X8;
1466             for (i = 0; i < 4; i++) {
1467                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
1468                 mx      = ff_h263_decode_motion(s, pred_x, s->f_code);
1469                 if (mx >= 0xffff)
1470                     return -1;
1471
1472                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1473                 if (my >= 0xffff)
1474                     return -1;
1475                 s->mv[0][i][0] = mx;
1476                 s->mv[0][i][1] = my;
1477                 mot_val[0]     = mx;
1478                 mot_val[1]     = my;
1479             }
1480         }
1481     } else if (s->pict_type == AV_PICTURE_TYPE_B) {
1482         int modb1;   // first bit of modb
1483         int modb2;   // second bit of modb
1484         int mb_type;
1485
1486         s->mb_intra = 0;  // B-frames never contain intra blocks
1487         s->mcsel    = 0;  //      ...               true gmc blocks
1488
1489         if (s->mb_x == 0) {
1490             for (i = 0; i < 2; i++) {
1491                 s->last_mv[i][0][0] =
1492                 s->last_mv[i][0][1] =
1493                 s->last_mv[i][1][0] =
1494                 s->last_mv[i][1][1] = 0;
1495             }
1496
1497             ff_thread_await_progress(&s->next_picture_ptr->tf, s->mb_y, 0);
1498         }
1499
1500         /* if we skipped it in the future P-frame than skip it now too */
1501         s->mb_skipped = s->next_picture.mbskip_table[s->mb_y * s->mb_stride + s->mb_x];  // Note, skiptab=0 if last was GMC
1502
1503         if (s->mb_skipped) {
1504             /* skip mb */
1505             for (i = 0; i < 6; i++)
1506                 s->block_last_index[i] = -1;
1507
1508             s->mv_dir      = MV_DIR_FORWARD;
1509             s->mv_type     = MV_TYPE_16X16;
1510             s->mv[0][0][0] =
1511             s->mv[0][0][1] =
1512             s->mv[1][0][0] =
1513             s->mv[1][0][1] = 0;
1514             s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1515                                              MB_TYPE_16x16 |
1516                                              MB_TYPE_L0;
1517             goto end;
1518         }
1519
1520         modb1 = get_bits1(&s->gb);
1521         if (modb1) {
1522             // like MB_TYPE_B_DIRECT but no vectors coded
1523             mb_type = MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1;
1524             cbp     = 0;
1525         } else {
1526             modb2   = get_bits1(&s->gb);
1527             mb_type = get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
1528             if (mb_type < 0) {
1529                 av_log(s->avctx, AV_LOG_ERROR, "illegal MB_type\n");
1530                 return -1;
1531             }
1532             mb_type = mb_type_b_map[mb_type];
1533             if (modb2) {
1534                 cbp = 0;
1535             } else {
1536                 s->bdsp.clear_blocks(s->block[0]);
1537                 cbp = get_bits(&s->gb, 6);
1538             }
1539
1540             if ((!IS_DIRECT(mb_type)) && cbp) {
1541                 if (get_bits1(&s->gb))
1542                     ff_set_qscale(s, s->qscale + get_bits1(&s->gb) * 4 - 2);
1543             }
1544
1545             if (!s->progressive_sequence) {
1546                 if (cbp)
1547                     s->interlaced_dct = get_bits1(&s->gb);
1548
1549                 if (!IS_DIRECT(mb_type) && get_bits1(&s->gb)) {
1550                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
1551                     mb_type &= ~MB_TYPE_16x16;
1552
1553                     if (USES_LIST(mb_type, 0)) {
1554                         s->field_select[0][0] = get_bits1(&s->gb);
1555                         s->field_select[0][1] = get_bits1(&s->gb);
1556                     }
1557                     if (USES_LIST(mb_type, 1)) {
1558                         s->field_select[1][0] = get_bits1(&s->gb);
1559                         s->field_select[1][1] = get_bits1(&s->gb);
1560                     }
1561                 }
1562             }
1563
1564             s->mv_dir = 0;
1565             if ((mb_type & (MB_TYPE_DIRECT2 | MB_TYPE_INTERLACED)) == 0) {
1566                 s->mv_type = MV_TYPE_16X16;
1567
1568                 if (USES_LIST(mb_type, 0)) {
1569                     s->mv_dir = MV_DIR_FORWARD;
1570
1571                     mx = ff_h263_decode_motion(s, s->last_mv[0][0][0], s->f_code);
1572                     my = ff_h263_decode_motion(s, s->last_mv[0][0][1], s->f_code);
1573                     s->last_mv[0][1][0] =
1574                     s->last_mv[0][0][0] =
1575                     s->mv[0][0][0]      = mx;
1576                     s->last_mv[0][1][1] =
1577                     s->last_mv[0][0][1] =
1578                     s->mv[0][0][1]      = my;
1579                 }
1580
1581                 if (USES_LIST(mb_type, 1)) {
1582                     s->mv_dir |= MV_DIR_BACKWARD;
1583
1584                     mx = ff_h263_decode_motion(s, s->last_mv[1][0][0], s->b_code);
1585                     my = ff_h263_decode_motion(s, s->last_mv[1][0][1], s->b_code);
1586                     s->last_mv[1][1][0] =
1587                     s->last_mv[1][0][0] =
1588                     s->mv[1][0][0]      = mx;
1589                     s->last_mv[1][1][1] =
1590                     s->last_mv[1][0][1] =
1591                     s->mv[1][0][1]      = my;
1592                 }
1593             } else if (!IS_DIRECT(mb_type)) {
1594                 s->mv_type = MV_TYPE_FIELD;
1595
1596                 if (USES_LIST(mb_type, 0)) {
1597                     s->mv_dir = MV_DIR_FORWARD;
1598
1599                     for (i = 0; i < 2; i++) {
1600                         mx = ff_h263_decode_motion(s, s->last_mv[0][i][0], s->f_code);
1601                         my = ff_h263_decode_motion(s, s->last_mv[0][i][1] / 2, s->f_code);
1602                         s->last_mv[0][i][0] =
1603                         s->mv[0][i][0]      = mx;
1604                         s->last_mv[0][i][1] = (s->mv[0][i][1] = my) * 2;
1605                     }
1606                 }
1607
1608                 if (USES_LIST(mb_type, 1)) {
1609                     s->mv_dir |= MV_DIR_BACKWARD;
1610
1611                     for (i = 0; i < 2; i++) {
1612                         mx = ff_h263_decode_motion(s, s->last_mv[1][i][0], s->b_code);
1613                         my = ff_h263_decode_motion(s, s->last_mv[1][i][1] / 2, s->b_code);
1614                         s->last_mv[1][i][0] =
1615                         s->mv[1][i][0]      = mx;
1616                         s->last_mv[1][i][1] = (s->mv[1][i][1] = my) * 2;
1617                     }
1618                 }
1619             }
1620         }
1621
1622         if (IS_DIRECT(mb_type)) {
1623             if (IS_SKIP(mb_type)) {
1624                 mx =
1625                 my = 0;
1626             } else {
1627                 mx = ff_h263_decode_motion(s, 0, 1);
1628                 my = ff_h263_decode_motion(s, 0, 1);
1629             }
1630
1631             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
1632             mb_type  |= ff_mpeg4_set_direct_mv(s, mx, my);
1633         }
1634         s->current_picture.mb_type[xy] = mb_type;
1635     } else { /* I-Frame */
1636         do {
1637             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
1638             if (cbpc < 0) {
1639                 av_log(s->avctx, AV_LOG_ERROR,
1640                        "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1641                 return -1;
1642             }
1643         } while (cbpc == 8);
1644
1645         dquant = cbpc & 4;
1646         s->mb_intra = 1;
1647
1648 intra:
1649         s->ac_pred = get_bits1(&s->gb);
1650         if (s->ac_pred)
1651             s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
1652         else
1653             s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
1654
1655         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
1656         if (cbpy < 0) {
1657             av_log(s->avctx, AV_LOG_ERROR,
1658                    "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
1659             return -1;
1660         }
1661         cbp = (cbpc & 3) | (cbpy << 2);
1662
1663         ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1664
1665         if (dquant)
1666             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1667
1668         if (!s->progressive_sequence)
1669             s->interlaced_dct = get_bits1(&s->gb);
1670
1671         s->bdsp.clear_blocks(s->block[0]);
1672         /* decode each block */
1673         for (i = 0; i < 6; i++) {
1674             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 1, 0) < 0)
1675                 return -1;
1676             cbp += cbp;
1677         }
1678         goto end;
1679     }
1680
1681     /* decode each block */
1682     for (i = 0; i < 6; i++) {
1683         if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 0, 0) < 0)
1684             return -1;
1685         cbp += cbp;
1686     }
1687
1688 end:
1689     /* per-MB end of slice check */
1690     if (s->codec_id == AV_CODEC_ID_MPEG4) {
1691         int next = mpeg4_is_resync(ctx);
1692         if (next) {
1693             if        (s->mb_x + s->mb_y*s->mb_width + 1 >  next && (s->avctx->err_recognition & AV_EF_AGGRESSIVE)) {
1694                 return -1;
1695             } else if (s->mb_x + s->mb_y*s->mb_width + 1 >= next)
1696                 return SLICE_END;
1697
1698             if (s->pict_type == AV_PICTURE_TYPE_B) {
1699                 const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1700                 ff_thread_await_progress(&s->next_picture_ptr->tf,
1701                                          (s->mb_x + delta >= s->mb_width)
1702                                          ? FFMIN(s->mb_y + 1, s->mb_height - 1)
1703                                          : s->mb_y, 0);
1704                 if (s->next_picture.mbskip_table[xy + delta])
1705                     return SLICE_OK;
1706             }
1707
1708             return SLICE_END;
1709         }
1710     }
1711
1712     return SLICE_OK;
1713 }
1714
1715 static int mpeg4_decode_gop_header(MpegEncContext *s, GetBitContext *gb)
1716 {
1717     int hours, minutes, seconds;
1718
1719     if (!show_bits(gb, 23)) {
1720         av_log(s->avctx, AV_LOG_WARNING, "GOP header invalid\n");
1721         return -1;
1722     }
1723
1724     hours   = get_bits(gb, 5);
1725     minutes = get_bits(gb, 6);
1726     check_marker(s->avctx, gb, "in gop_header");
1727     seconds = get_bits(gb, 6);
1728
1729     s->time_base = seconds + 60*(minutes + 60*hours);
1730
1731     skip_bits1(gb);
1732     skip_bits1(gb);
1733
1734     return 0;
1735 }
1736
1737 static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb)
1738 {
1739
1740     s->avctx->profile = get_bits(gb, 4);
1741     s->avctx->level   = get_bits(gb, 4);
1742
1743     // for Simple profile, level 0
1744     if (s->avctx->profile == 0 && s->avctx->level == 8) {
1745         s->avctx->level = 0;
1746     }
1747
1748     return 0;
1749 }
1750
1751 static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
1752 {
1753     MpegEncContext *s = &ctx->m;
1754     int width, height, vo_ver_id;
1755
1756     /* vol header */
1757     skip_bits(gb, 1);                   /* random access */
1758     s->vo_type = get_bits(gb, 8);
1759     if (get_bits1(gb) != 0) {           /* is_ol_id */
1760         vo_ver_id = get_bits(gb, 4);    /* vo_ver_id */
1761         skip_bits(gb, 3);               /* vo_priority */
1762     } else {
1763         vo_ver_id = 1;
1764     }
1765     s->aspect_ratio_info = get_bits(gb, 4);
1766     if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1767         s->avctx->sample_aspect_ratio.num = get_bits(gb, 8);  // par_width
1768         s->avctx->sample_aspect_ratio.den = get_bits(gb, 8);  // par_height
1769     } else {
1770         s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[s->aspect_ratio_info];
1771     }
1772
1773     if ((ctx->vol_control_parameters = get_bits1(gb))) { /* vol control parameter */
1774         int chroma_format = get_bits(gb, 2);
1775         if (chroma_format != CHROMA_420)
1776             av_log(s->avctx, AV_LOG_ERROR, "illegal chroma format\n");
1777
1778         s->low_delay = get_bits1(gb);
1779         if (get_bits1(gb)) {    /* vbv parameters */
1780             get_bits(gb, 15);   /* first_half_bitrate */
1781             check_marker(s->avctx, gb, "after first_half_bitrate");
1782             get_bits(gb, 15);   /* latter_half_bitrate */
1783             check_marker(s->avctx, gb, "after latter_half_bitrate");
1784             get_bits(gb, 15);   /* first_half_vbv_buffer_size */
1785             check_marker(s->avctx, gb, "after first_half_vbv_buffer_size");
1786             get_bits(gb, 3);    /* latter_half_vbv_buffer_size */
1787             get_bits(gb, 11);   /* first_half_vbv_occupancy */
1788             check_marker(s->avctx, gb, "after first_half_vbv_occupancy");
1789             get_bits(gb, 15);   /* latter_half_vbv_occupancy */
1790             check_marker(s->avctx, gb, "after latter_half_vbv_occupancy");
1791         }
1792     } else {
1793         /* is setting low delay flag only once the smartest thing to do?
1794          * low delay detection will not be overridden. */
1795         if (s->picture_number == 0) {
1796             switch(s->vo_type) {
1797             case SIMPLE_VO_TYPE:
1798             case ADV_SIMPLE_VO_TYPE:
1799                 s->low_delay = 1;
1800                 break;
1801             default:
1802                 s->low_delay = 0;
1803             }
1804         }
1805     }
1806
1807     ctx->shape = get_bits(gb, 2); /* vol shape */
1808     if (ctx->shape != RECT_SHAPE)
1809         av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
1810     if (ctx->shape == GRAY_SHAPE && vo_ver_id != 1) {
1811         av_log(s->avctx, AV_LOG_ERROR, "Gray shape not supported\n");
1812         skip_bits(gb, 4);  /* video_object_layer_shape_extension */
1813     }
1814
1815     check_marker(s->avctx, gb, "before time_increment_resolution");
1816
1817     s->avctx->framerate.num = get_bits(gb, 16);
1818     if (!s->avctx->framerate.num) {
1819         av_log(s->avctx, AV_LOG_ERROR, "framerate==0\n");
1820         return AVERROR_INVALIDDATA;
1821     }
1822
1823     ctx->time_increment_bits = av_log2(s->avctx->framerate.num - 1) + 1;
1824     if (ctx->time_increment_bits < 1)
1825         ctx->time_increment_bits = 1;
1826
1827     check_marker(s->avctx, gb, "before fixed_vop_rate");
1828
1829     if (get_bits1(gb) != 0)     /* fixed_vop_rate  */
1830         s->avctx->framerate.den = get_bits(gb, ctx->time_increment_bits);
1831     else
1832         s->avctx->framerate.den = 1;
1833
1834     s->avctx->time_base = av_inv_q(av_mul_q(s->avctx->framerate, (AVRational){s->avctx->ticks_per_frame, 1}));
1835
1836     ctx->t_frame = 0;
1837
1838     if (ctx->shape != BIN_ONLY_SHAPE) {
1839         if (ctx->shape == RECT_SHAPE) {
1840             check_marker(s->avctx, gb, "before width");
1841             width = get_bits(gb, 13);
1842             check_marker(s->avctx, gb, "before height");
1843             height = get_bits(gb, 13);
1844             check_marker(s->avctx, gb, "after height");
1845             if (width && height &&  /* they should be non zero but who knows */
1846                 !(s->width && s->codec_tag == AV_RL32("MP4S"))) {
1847                 if (s->width && s->height &&
1848                     (s->width != width || s->height != height))
1849                     s->context_reinit = 1;
1850                 s->width  = width;
1851                 s->height = height;
1852             }
1853         }
1854
1855         s->progressive_sequence  =
1856         s->progressive_frame     = get_bits1(gb) ^ 1;
1857         s->interlaced_dct        = 0;
1858         if (!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
1859             av_log(s->avctx, AV_LOG_INFO,           /* OBMC Disable */
1860                    "MPEG-4 OBMC not supported (very likely buggy encoder)\n");
1861         if (vo_ver_id == 1)
1862             ctx->vol_sprite_usage = get_bits1(gb);    /* vol_sprite_usage */
1863         else
1864             ctx->vol_sprite_usage = get_bits(gb, 2);  /* vol_sprite_usage */
1865
1866         if (ctx->vol_sprite_usage == STATIC_SPRITE)
1867             av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
1868         if (ctx->vol_sprite_usage == STATIC_SPRITE ||
1869             ctx->vol_sprite_usage == GMC_SPRITE) {
1870             if (ctx->vol_sprite_usage == STATIC_SPRITE) {
1871                 skip_bits(gb, 13); // sprite_width
1872                 check_marker(s->avctx, gb, "after sprite_width");
1873                 skip_bits(gb, 13); // sprite_height
1874                 check_marker(s->avctx, gb, "after sprite_height");
1875                 skip_bits(gb, 13); // sprite_left
1876                 check_marker(s->avctx, gb, "after sprite_left");
1877                 skip_bits(gb, 13); // sprite_top
1878                 check_marker(s->avctx, gb, "after sprite_top");
1879             }
1880             ctx->num_sprite_warping_points = get_bits(gb, 6);
1881             if (ctx->num_sprite_warping_points > 3) {
1882                 av_log(s->avctx, AV_LOG_ERROR,
1883                        "%d sprite_warping_points\n",
1884                        ctx->num_sprite_warping_points);
1885                 ctx->num_sprite_warping_points = 0;
1886                 return AVERROR_INVALIDDATA;
1887             }
1888             s->sprite_warping_accuracy  = get_bits(gb, 2);
1889             ctx->sprite_brightness_change = get_bits1(gb);
1890             if (ctx->vol_sprite_usage == STATIC_SPRITE)
1891                 skip_bits1(gb); // low_latency_sprite
1892         }
1893         // FIXME sadct disable bit if verid!=1 && shape not rect
1894
1895         if (get_bits1(gb) == 1) {                   /* not_8_bit */
1896             s->quant_precision = get_bits(gb, 4);   /* quant_precision */
1897             if (get_bits(gb, 4) != 8)               /* bits_per_pixel */
1898                 av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n");
1899             if (s->quant_precision != 5)
1900                 av_log(s->avctx, AV_LOG_ERROR,
1901                        "quant precision %d\n", s->quant_precision);
1902             if (s->quant_precision<3 || s->quant_precision>9) {
1903                 s->quant_precision = 5;
1904             }
1905         } else {
1906             s->quant_precision = 5;
1907         }
1908
1909         // FIXME a bunch of grayscale shape things
1910
1911         if ((s->mpeg_quant = get_bits1(gb))) { /* vol_quant_type */
1912             int i, v;
1913
1914             /* load default matrixes */
1915             for (i = 0; i < 64; i++) {
1916                 int j = s->idsp.idct_permutation[i];
1917                 v = ff_mpeg4_default_intra_matrix[i];
1918                 s->intra_matrix[j]        = v;
1919                 s->chroma_intra_matrix[j] = v;
1920
1921                 v = ff_mpeg4_default_non_intra_matrix[i];
1922                 s->inter_matrix[j]        = v;
1923                 s->chroma_inter_matrix[j] = v;
1924             }
1925
1926             /* load custom intra matrix */
1927             if (get_bits1(gb)) {
1928                 int last = 0;
1929                 for (i = 0; i < 64; i++) {
1930                     int j;
1931                     if (get_bits_left(gb) < 8) {
1932                         av_log(s->avctx, AV_LOG_ERROR, "insufficient data for custom matrix\n");
1933                         return AVERROR_INVALIDDATA;
1934                     }
1935                     v = get_bits(gb, 8);
1936                     if (v == 0)
1937                         break;
1938
1939                     last = v;
1940                     j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1941                     s->intra_matrix[j]        = last;
1942                     s->chroma_intra_matrix[j] = last;
1943                 }
1944
1945                 /* replicate last value */
1946                 for (; i < 64; i++) {
1947                     int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1948                     s->intra_matrix[j]        = last;
1949                     s->chroma_intra_matrix[j] = last;
1950                 }
1951             }
1952
1953             /* load custom non intra matrix */
1954             if (get_bits1(gb)) {
1955                 int last = 0;
1956                 for (i = 0; i < 64; i++) {
1957                     int j;
1958                     if (get_bits_left(gb) < 8) {
1959                         av_log(s->avctx, AV_LOG_ERROR, "insufficient data for custom matrix\n");
1960                         return AVERROR_INVALIDDATA;
1961                     }
1962                     v = get_bits(gb, 8);
1963                     if (v == 0)
1964                         break;
1965
1966                     last = v;
1967                     j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1968                     s->inter_matrix[j]        = v;
1969                     s->chroma_inter_matrix[j] = v;
1970                 }
1971
1972                 /* replicate last value */
1973                 for (; i < 64; i++) {
1974                     int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
1975                     s->inter_matrix[j]        = last;
1976                     s->chroma_inter_matrix[j] = last;
1977                 }
1978             }
1979
1980             // FIXME a bunch of grayscale shape things
1981         }
1982
1983         if (vo_ver_id != 1)
1984             s->quarter_sample = get_bits1(gb);
1985         else
1986             s->quarter_sample = 0;
1987
1988         if (get_bits_left(gb) < 4) {
1989             av_log(s->avctx, AV_LOG_ERROR, "VOL Header truncated\n");
1990             return AVERROR_INVALIDDATA;
1991         }
1992
1993         if (!get_bits1(gb)) {
1994             int pos               = get_bits_count(gb);
1995             int estimation_method = get_bits(gb, 2);
1996             if (estimation_method < 2) {
1997                 if (!get_bits1(gb)) {
1998                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* opaque */
1999                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* transparent */
2000                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_cae */
2001                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* inter_cae */
2002                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* no_update */
2003                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* upsampling */
2004                 }
2005                 if (!get_bits1(gb)) {
2006                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_blocks */
2007                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter_blocks */
2008                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter4v_blocks */
2009                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* not coded blocks */
2010                 }
2011                 if (!check_marker(s->avctx, gb, "in complexity estimation part 1")) {
2012                     skip_bits_long(gb, pos - get_bits_count(gb));
2013                     goto no_cplx_est;
2014                 }
2015                 if (!get_bits1(gb)) {
2016                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_coeffs */
2017                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_lines */
2018                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* vlc_syms */
2019                     ctx->cplx_estimation_trash_i += 4 * get_bits1(gb);  /* vlc_bits */
2020                 }
2021                 if (!get_bits1(gb)) {
2022                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* apm */
2023                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* npm */
2024                     ctx->cplx_estimation_trash_b += 8 * get_bits1(gb);  /* interpolate_mc_q */
2025                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* forwback_mc_q */
2026                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel2 */
2027                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel4 */
2028                 }
2029                 if (!check_marker(s->avctx, gb, "in complexity estimation part 2")) {
2030                     skip_bits_long(gb, pos - get_bits_count(gb));
2031                     goto no_cplx_est;
2032                 }
2033                 if (estimation_method == 1) {
2034                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* sadct */
2035                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* qpel */
2036                 }
2037             } else
2038                 av_log(s->avctx, AV_LOG_ERROR,
2039                        "Invalid Complexity estimation method %d\n",
2040                        estimation_method);
2041         } else {
2042
2043 no_cplx_est:
2044             ctx->cplx_estimation_trash_i =
2045             ctx->cplx_estimation_trash_p =
2046             ctx->cplx_estimation_trash_b = 0;
2047         }
2048
2049         ctx->resync_marker = !get_bits1(gb); /* resync_marker_disabled */
2050
2051         s->data_partitioning = get_bits1(gb);
2052         if (s->data_partitioning)
2053             ctx->rvlc = get_bits1(gb);
2054
2055         if (vo_ver_id != 1) {
2056             ctx->new_pred = get_bits1(gb);
2057             if (ctx->new_pred) {
2058                 av_log(s->avctx, AV_LOG_ERROR, "new pred not supported\n");
2059                 skip_bits(gb, 2); /* requested upstream message type */
2060                 skip_bits1(gb);   /* newpred segment type */
2061             }
2062             if (get_bits1(gb)) // reduced_res_vop
2063                 av_log(s->avctx, AV_LOG_ERROR,
2064                        "reduced resolution VOP not supported\n");
2065         } else {
2066             ctx->new_pred = 0;
2067         }
2068
2069         ctx->scalability = get_bits1(gb);
2070
2071         if (ctx->scalability) {
2072             GetBitContext bak = *gb;
2073             int h_sampling_factor_n;
2074             int h_sampling_factor_m;
2075             int v_sampling_factor_n;
2076             int v_sampling_factor_m;
2077
2078             skip_bits1(gb);    // hierarchy_type
2079             skip_bits(gb, 4);  /* ref_layer_id */
2080             skip_bits1(gb);    /* ref_layer_sampling_dir */
2081             h_sampling_factor_n = get_bits(gb, 5);
2082             h_sampling_factor_m = get_bits(gb, 5);
2083             v_sampling_factor_n = get_bits(gb, 5);
2084             v_sampling_factor_m = get_bits(gb, 5);
2085             ctx->enhancement_type = get_bits1(gb);
2086
2087             if (h_sampling_factor_n == 0 || h_sampling_factor_m == 0 ||
2088                 v_sampling_factor_n == 0 || v_sampling_factor_m == 0) {
2089                 /* illegal scalability header (VERY broken encoder),
2090                  * trying to workaround */
2091                 ctx->scalability = 0;
2092                 *gb            = bak;
2093             } else
2094                 av_log(s->avctx, AV_LOG_ERROR, "scalability not supported\n");
2095
2096             // bin shape stuff FIXME
2097         }
2098     }
2099
2100     if (s->avctx->debug&FF_DEBUG_PICT_INFO) {
2101         av_log(s->avctx, AV_LOG_DEBUG, "tb %d/%d, tincrbits:%d, qp_prec:%d, ps:%d, low_delay:%d  %s%s%s%s\n",
2102                s->avctx->framerate.den, s->avctx->framerate.num,
2103                ctx->time_increment_bits,
2104                s->quant_precision,
2105                s->progressive_sequence,
2106                s->low_delay,
2107                ctx->scalability ? "scalability " :"" , s->quarter_sample ? "qpel " : "",
2108                s->data_partitioning ? "partition " : "", ctx->rvlc ? "rvlc " : ""
2109         );
2110     }
2111
2112     return 0;
2113 }
2114
2115 /**
2116  * Decode the user data stuff in the header.
2117  * Also initializes divx/xvid/lavc_version/build.
2118  */
2119 static int decode_user_data(Mpeg4DecContext *ctx, GetBitContext *gb)
2120 {
2121     MpegEncContext *s = &ctx->m;
2122     char buf[256];
2123     int i;
2124     int e;
2125     int ver = 0, build = 0, ver2 = 0, ver3 = 0;
2126     char last;
2127
2128     for (i = 0; i < 255 && get_bits_count(gb) < gb->size_in_bits; i++) {
2129         if (show_bits(gb, 23) == 0)
2130             break;
2131         buf[i] = get_bits(gb, 8);
2132     }
2133     buf[i] = 0;
2134
2135     /* divx detection */
2136     e = sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
2137     if (e < 2)
2138         e = sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
2139     if (e >= 2) {
2140         ctx->divx_version = ver;
2141         ctx->divx_build   = build;
2142         s->divx_packed  = e == 3 && last == 'p';
2143     }
2144
2145     /* libavcodec detection */
2146     e = sscanf(buf, "FFmpe%*[^b]b%d", &build) + 3;
2147     if (e != 4)
2148         e = sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
2149     if (e != 4) {
2150         e = sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3) + 1;
2151         if (e > 1)
2152             build = (ver << 16) + (ver2 << 8) + ver3;
2153     }
2154     if (e != 4) {
2155         if (strcmp(buf, "ffmpeg") == 0)
2156             ctx->lavc_build = 4600;
2157     }
2158     if (e == 4)
2159         ctx->lavc_build = build;
2160
2161     /* Xvid detection */
2162     e = sscanf(buf, "XviD%d", &build);
2163     if (e == 1)
2164         ctx->xvid_build = build;
2165
2166     return 0;
2167 }
2168
2169 int ff_mpeg4_workaround_bugs(AVCodecContext *avctx)
2170 {
2171     Mpeg4DecContext *ctx = avctx->priv_data;
2172     MpegEncContext *s = &ctx->m;
2173
2174     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1) {
2175         if (s->codec_tag        == AV_RL32("XVID") ||
2176             s->codec_tag        == AV_RL32("XVIX") ||
2177             s->codec_tag        == AV_RL32("RMP4") ||
2178             s->codec_tag        == AV_RL32("ZMP4") ||
2179             s->codec_tag        == AV_RL32("SIPP"))
2180             ctx->xvid_build = 0;
2181     }
2182
2183     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1)
2184         if (s->codec_tag == AV_RL32("DIVX") && s->vo_type == 0 &&
2185             ctx->vol_control_parameters == 0)
2186             ctx->divx_version = 400;  // divx 4
2187
2188     if (ctx->xvid_build >= 0 && ctx->divx_version >= 0) {
2189         ctx->divx_version =
2190         ctx->divx_build   = -1;
2191     }
2192
2193     if (s->workaround_bugs & FF_BUG_AUTODETECT) {
2194         if (s->codec_tag == AV_RL32("XVIX"))
2195             s->workaround_bugs |= FF_BUG_XVID_ILACE;
2196
2197         if (s->codec_tag == AV_RL32("UMP4"))
2198             s->workaround_bugs |= FF_BUG_UMP4;
2199
2200         if (ctx->divx_version >= 500 && ctx->divx_build < 1814)
2201             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2202
2203         if (ctx->divx_version > 502 && ctx->divx_build < 1814)
2204             s->workaround_bugs |= FF_BUG_QPEL_CHROMA2;
2205
2206         if (ctx->xvid_build <= 3U)
2207             s->padding_bug_score = 256 * 256 * 256 * 64;
2208
2209         if (ctx->xvid_build <= 1U)
2210             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2211
2212         if (ctx->xvid_build <= 12U)
2213             s->workaround_bugs |= FF_BUG_EDGE;
2214
2215         if (ctx->xvid_build <= 32U)
2216             s->workaround_bugs |= FF_BUG_DC_CLIP;
2217
2218 #define SET_QPEL_FUNC(postfix1, postfix2)                           \
2219     s->qdsp.put_        ## postfix1 = ff_put_        ## postfix2;   \
2220     s->qdsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;   \
2221     s->qdsp.avg_        ## postfix1 = ff_avg_        ## postfix2;
2222
2223         if (ctx->lavc_build < 4653U)
2224             s->workaround_bugs |= FF_BUG_STD_QPEL;
2225
2226         if (ctx->lavc_build < 4655U)
2227             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2228
2229         if (ctx->lavc_build < 4670U)
2230             s->workaround_bugs |= FF_BUG_EDGE;
2231
2232         if (ctx->lavc_build <= 4712U)
2233             s->workaround_bugs |= FF_BUG_DC_CLIP;
2234
2235         if ((ctx->lavc_build&0xFF) >= 100) {
2236             if (ctx->lavc_build > 3621476 && ctx->lavc_build < 3752552 &&
2237                (ctx->lavc_build < 3752037 || ctx->lavc_build > 3752191) // 3.2.1+
2238             )
2239                 s->workaround_bugs |= FF_BUG_IEDGE;
2240         }
2241
2242         if (ctx->divx_version >= 0)
2243             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2244         if (ctx->divx_version == 501 && ctx->divx_build == 20020416)
2245             s->padding_bug_score = 256 * 256 * 256 * 64;
2246
2247         if (ctx->divx_version < 500U)
2248             s->workaround_bugs |= FF_BUG_EDGE;
2249
2250         if (ctx->divx_version >= 0)
2251             s->workaround_bugs |= FF_BUG_HPEL_CHROMA;
2252     }
2253
2254     if (s->workaround_bugs & FF_BUG_STD_QPEL) {
2255         SET_QPEL_FUNC(qpel_pixels_tab[0][5], qpel16_mc11_old_c)
2256         SET_QPEL_FUNC(qpel_pixels_tab[0][7], qpel16_mc31_old_c)
2257         SET_QPEL_FUNC(qpel_pixels_tab[0][9], qpel16_mc12_old_c)
2258         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
2259         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
2260         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
2261
2262         SET_QPEL_FUNC(qpel_pixels_tab[1][5], qpel8_mc11_old_c)
2263         SET_QPEL_FUNC(qpel_pixels_tab[1][7], qpel8_mc31_old_c)
2264         SET_QPEL_FUNC(qpel_pixels_tab[1][9], qpel8_mc12_old_c)
2265         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
2266         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
2267         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
2268     }
2269
2270     if (avctx->debug & FF_DEBUG_BUGS)
2271         av_log(s->avctx, AV_LOG_DEBUG,
2272                "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
2273                s->workaround_bugs, ctx->lavc_build, ctx->xvid_build,
2274                ctx->divx_version, ctx->divx_build, s->divx_packed ? "p" : "");
2275
2276     if (CONFIG_MPEG4_DECODER && ctx->xvid_build >= 0 &&
2277         s->codec_id == AV_CODEC_ID_MPEG4 &&
2278         avctx->idct_algo == FF_IDCT_AUTO) {
2279         avctx->idct_algo = FF_IDCT_XVID;
2280         ff_mpv_idct_init(s);
2281         return 1;
2282     }
2283
2284     return 0;
2285 }
2286
2287 static int decode_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2288 {
2289     MpegEncContext *s = &ctx->m;
2290     int time_incr, time_increment;
2291     int64_t pts;
2292
2293     s->mcsel       = 0;
2294     s->pict_type = get_bits(gb, 2) + AV_PICTURE_TYPE_I;        /* pict type: I = 0 , P = 1 */
2295     if (s->pict_type == AV_PICTURE_TYPE_B && s->low_delay &&
2296         ctx->vol_control_parameters == 0 && !(s->avctx->flags & AV_CODEC_FLAG_LOW_DELAY)) {
2297         av_log(s->avctx, AV_LOG_ERROR, "low_delay flag set incorrectly, clearing it\n");
2298         s->low_delay = 0;
2299     }
2300
2301     s->partitioned_frame = s->data_partitioning && s->pict_type != AV_PICTURE_TYPE_B;
2302     if (s->partitioned_frame)
2303         s->decode_mb = mpeg4_decode_partitioned_mb;
2304     else
2305         s->decode_mb = mpeg4_decode_mb;
2306
2307     time_incr = 0;
2308     while (get_bits1(gb) != 0)
2309         time_incr++;
2310
2311     check_marker(s->avctx, gb, "before time_increment");
2312
2313     if (ctx->time_increment_bits == 0 ||
2314         !(show_bits(gb, ctx->time_increment_bits + 1) & 1)) {
2315         av_log(s->avctx, AV_LOG_WARNING,
2316                "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);
2317
2318         for (ctx->time_increment_bits = 1;
2319              ctx->time_increment_bits < 16;
2320              ctx->time_increment_bits++) {
2321             if (s->pict_type == AV_PICTURE_TYPE_P ||
2322                 (s->pict_type == AV_PICTURE_TYPE_S &&
2323                  ctx->vol_sprite_usage == GMC_SPRITE)) {
2324                 if ((show_bits(gb, ctx->time_increment_bits + 6) & 0x37) == 0x30)
2325                     break;
2326             } else if ((show_bits(gb, ctx->time_increment_bits + 5) & 0x1F) == 0x18)
2327                 break;
2328         }
2329
2330         av_log(s->avctx, AV_LOG_WARNING,
2331                "time_increment_bits set to %d bits, based on bitstream analysis\n", ctx->time_increment_bits);
2332         if (s->avctx->framerate.num && 4*s->avctx->framerate.num < 1<<ctx->time_increment_bits) {
2333             s->avctx->framerate.num = 1<<ctx->time_increment_bits;
2334             s->avctx->time_base = av_inv_q(av_mul_q(s->avctx->framerate, (AVRational){s->avctx->ticks_per_frame, 1}));
2335         }
2336     }
2337
2338     if (IS_3IV1)
2339         time_increment = get_bits1(gb);        // FIXME investigate further
2340     else
2341         time_increment = get_bits(gb, ctx->time_increment_bits);
2342
2343     if (s->pict_type != AV_PICTURE_TYPE_B) {
2344         s->last_time_base = s->time_base;
2345         s->time_base     += time_incr;
2346         s->time = s->time_base * (int64_t)s->avctx->framerate.num + time_increment;
2347         if (s->workaround_bugs & FF_BUG_UMP4) {
2348             if (s->time < s->last_non_b_time) {
2349                 /* header is not mpeg-4-compatible, broken encoder,
2350                  * trying to workaround */
2351                 s->time_base++;
2352                 s->time += s->avctx->framerate.num;
2353             }
2354         }
2355         s->pp_time         = s->time - s->last_non_b_time;
2356         s->last_non_b_time = s->time;
2357     } else {
2358         s->time    = (s->last_time_base + time_incr) * (int64_t)s->avctx->framerate.num + time_increment;
2359         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
2360         if (s->pp_time <= s->pb_time ||
2361             s->pp_time <= s->pp_time - s->pb_time ||
2362             s->pp_time <= 0) {
2363             /* messed up order, maybe after seeking? skipping current B-frame */
2364             return FRAME_SKIPPED;
2365         }
2366         ff_mpeg4_init_direct_mv(s);
2367
2368         if (ctx->t_frame == 0)
2369             ctx->t_frame = s->pb_time;
2370         if (ctx->t_frame == 0)
2371             ctx->t_frame = 1;  // 1/0 protection
2372         s->pp_field_time = (ROUNDED_DIV(s->last_non_b_time, ctx->t_frame) -
2373                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2374         s->pb_field_time = (ROUNDED_DIV(s->time, ctx->t_frame) -
2375                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2376         if (s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1) {
2377             s->pb_field_time = 2;
2378             s->pp_field_time = 4;
2379             if (!s->progressive_sequence)
2380                 return FRAME_SKIPPED;
2381         }
2382     }
2383
2384     if (s->avctx->framerate.den)
2385         pts = ROUNDED_DIV(s->time, s->avctx->framerate.den);
2386     else
2387         pts = AV_NOPTS_VALUE;
2388     ff_dlog(s->avctx, "MPEG4 PTS: %"PRId64"\n", pts);
2389
2390     check_marker(s->avctx, gb, "before vop_coded");
2391
2392     /* vop coded */
2393     if (get_bits1(gb) != 1) {
2394         if (s->avctx->debug & FF_DEBUG_PICT_INFO)
2395             av_log(s->avctx, AV_LOG_ERROR, "vop not coded\n");
2396         return FRAME_SKIPPED;
2397     }
2398     if (ctx->new_pred)
2399         decode_new_pred(ctx, gb);
2400
2401     if (ctx->shape != BIN_ONLY_SHAPE &&
2402                     (s->pict_type == AV_PICTURE_TYPE_P ||
2403                      (s->pict_type == AV_PICTURE_TYPE_S &&
2404                       ctx->vol_sprite_usage == GMC_SPRITE))) {
2405         /* rounding type for motion estimation */
2406         s->no_rounding = get_bits1(gb);
2407     } else {
2408         s->no_rounding = 0;
2409     }
2410     // FIXME reduced res stuff
2411
2412     if (ctx->shape != RECT_SHAPE) {
2413         if (ctx->vol_sprite_usage != 1 || s->pict_type != AV_PICTURE_TYPE_I) {
2414             skip_bits(gb, 13);  /* width */
2415             check_marker(s->avctx, gb, "after width");
2416             skip_bits(gb, 13);  /* height */
2417             check_marker(s->avctx, gb, "after height");
2418             skip_bits(gb, 13);  /* hor_spat_ref */
2419             check_marker(s->avctx, gb, "after hor_spat_ref");
2420             skip_bits(gb, 13);  /* ver_spat_ref */
2421         }
2422         skip_bits1(gb);         /* change_CR_disable */
2423
2424         if (get_bits1(gb) != 0)
2425             skip_bits(gb, 8);   /* constant_alpha_value */
2426     }
2427
2428     // FIXME complexity estimation stuff
2429
2430     if (ctx->shape != BIN_ONLY_SHAPE) {
2431         skip_bits_long(gb, ctx->cplx_estimation_trash_i);
2432         if (s->pict_type != AV_PICTURE_TYPE_I)
2433             skip_bits_long(gb, ctx->cplx_estimation_trash_p);
2434         if (s->pict_type == AV_PICTURE_TYPE_B)
2435             skip_bits_long(gb, ctx->cplx_estimation_trash_b);
2436
2437         if (get_bits_left(gb) < 3) {
2438             av_log(s->avctx, AV_LOG_ERROR, "Header truncated\n");
2439             return AVERROR_INVALIDDATA;
2440         }
2441         ctx->intra_dc_threshold = ff_mpeg4_dc_threshold[get_bits(gb, 3)];
2442         if (!s->progressive_sequence) {
2443             s->top_field_first = get_bits1(gb);
2444             s->alternate_scan  = get_bits1(gb);
2445         } else
2446             s->alternate_scan = 0;
2447     }
2448
2449     if (s->alternate_scan) {
2450         ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable,   ff_alternate_vertical_scan);
2451         ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,   ff_alternate_vertical_scan);
2452         ff_init_scantable(s->idsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
2453         ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2454     } else {
2455         ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable,   ff_zigzag_direct);
2456         ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,   ff_zigzag_direct);
2457         ff_init_scantable(s->idsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
2458         ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2459     }
2460
2461     if (s->pict_type == AV_PICTURE_TYPE_S) {
2462         if((ctx->vol_sprite_usage == STATIC_SPRITE ||
2463             ctx->vol_sprite_usage == GMC_SPRITE)) {
2464             if (mpeg4_decode_sprite_trajectory(ctx, gb) < 0)
2465                 return AVERROR_INVALIDDATA;
2466             if (ctx->sprite_brightness_change)
2467                 av_log(s->avctx, AV_LOG_ERROR,
2468                     "sprite_brightness_change not supported\n");
2469             if (ctx->vol_sprite_usage == STATIC_SPRITE)
2470                 av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
2471         } else {
2472             memset(s->sprite_offset, 0, sizeof(s->sprite_offset));
2473             memset(s->sprite_delta, 0, sizeof(s->sprite_delta));
2474         }
2475     }
2476
2477     if (ctx->shape != BIN_ONLY_SHAPE) {
2478         s->chroma_qscale = s->qscale = get_bits(gb, s->quant_precision);
2479         if (s->qscale == 0) {
2480             av_log(s->avctx, AV_LOG_ERROR,
2481                    "Error, header damaged or not MPEG-4 header (qscale=0)\n");
2482             return AVERROR_INVALIDDATA;  // makes no sense to continue, as there is nothing left from the image then
2483         }
2484
2485         if (s->pict_type != AV_PICTURE_TYPE_I) {
2486             s->f_code = get_bits(gb, 3);        /* fcode_for */
2487             if (s->f_code == 0) {
2488                 av_log(s->avctx, AV_LOG_ERROR,
2489                        "Error, header damaged or not MPEG-4 header (f_code=0)\n");
2490                 s->f_code = 1;
2491                 return AVERROR_INVALIDDATA;  // makes no sense to continue, as there is nothing left from the image then
2492             }
2493         } else
2494             s->f_code = 1;
2495
2496         if (s->pict_type == AV_PICTURE_TYPE_B) {
2497             s->b_code = get_bits(gb, 3);
2498             if (s->b_code == 0) {
2499                 av_log(s->avctx, AV_LOG_ERROR,
2500                        "Error, header damaged or not MPEG4 header (b_code=0)\n");
2501                 s->b_code=1;
2502                 return AVERROR_INVALIDDATA; // makes no sense to continue, as the MV decoding will break very quickly
2503             }
2504         } else
2505             s->b_code = 1;
2506
2507         if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
2508             av_log(s->avctx, AV_LOG_DEBUG,
2509                    "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",
2510                    s->qscale, s->f_code, s->b_code,
2511                    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")),
2512                    gb->size_in_bits,s->progressive_sequence, s->alternate_scan,
2513                    s->top_field_first, s->quarter_sample ? "q" : "h",
2514                    s->data_partitioning, ctx->resync_marker,
2515                    ctx->num_sprite_warping_points, s->sprite_warping_accuracy,
2516                    1 - s->no_rounding, s->vo_type,
2517                    ctx->vol_control_parameters ? " VOLC" : " ", ctx->intra_dc_threshold,
2518                    ctx->cplx_estimation_trash_i, ctx->cplx_estimation_trash_p,
2519                    ctx->cplx_estimation_trash_b,
2520                    s->time,
2521                    time_increment
2522                   );
2523         }
2524
2525         if (!ctx->scalability) {
2526             if (ctx->shape != RECT_SHAPE && s->pict_type != AV_PICTURE_TYPE_I)
2527                 skip_bits1(gb);  // vop shape coding type
2528         } else {
2529             if (ctx->enhancement_type) {
2530                 int load_backward_shape = get_bits1(gb);
2531                 if (load_backward_shape)
2532                     av_log(s->avctx, AV_LOG_ERROR,
2533                            "load backward shape isn't supported\n");
2534             }
2535             skip_bits(gb, 2);  // ref_select_code
2536         }
2537     }
2538     /* detect buggy encoders which don't set the low_delay flag
2539      * (divx4/xvid/opendivx). Note we cannot detect divx5 without B-frames
2540      * easily (although it's buggy too) */
2541     if (s->vo_type == 0 && ctx->vol_control_parameters == 0 &&
2542         ctx->divx_version == -1 && s->picture_number == 0) {
2543         av_log(s->avctx, AV_LOG_WARNING,
2544                "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
2545         s->low_delay = 1;
2546     }
2547
2548     s->picture_number++;  // better than pic number==0 always ;)
2549
2550     // FIXME add short header support
2551     s->y_dc_scale_table = ff_mpeg4_y_dc_scale_table;
2552     s->c_dc_scale_table = ff_mpeg4_c_dc_scale_table;
2553
2554     if (s->workaround_bugs & FF_BUG_EDGE) {
2555         s->h_edge_pos = s->width;
2556         s->v_edge_pos = s->height;
2557     }
2558     return 0;
2559 }
2560
2561 /**
2562  * Decode MPEG-4 headers.
2563  * @return <0 if no VOP found (or a damaged one)
2564  *         FRAME_SKIPPED if a not coded VOP is found
2565  *         0 if a VOP is found
2566  */
2567 int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2568 {
2569     MpegEncContext *s = &ctx->m;
2570     unsigned startcode, v;
2571     int ret;
2572     int vol = 0;
2573
2574     /* search next start code */
2575     align_get_bits(gb);
2576
2577     if (s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630) {
2578         skip_bits(gb, 24);
2579         if (get_bits(gb, 8) == 0xF0)
2580             goto end;
2581     }
2582
2583     startcode = 0xff;
2584     for (;;) {
2585         if (get_bits_count(gb) >= gb->size_in_bits) {
2586             if (gb->size_in_bits == 8 &&
2587                 (ctx->divx_version >= 0 || ctx->xvid_build >= 0) || s->codec_tag == AV_RL32("QMP4")) {
2588                 av_log(s->avctx, AV_LOG_VERBOSE, "frame skip %d\n", gb->size_in_bits);
2589                 return FRAME_SKIPPED;  // divx bug
2590             } else
2591                 return -1;  // end of stream
2592         }
2593
2594         /* use the bits after the test */
2595         v = get_bits(gb, 8);
2596         startcode = ((startcode << 8) | v) & 0xffffffff;
2597
2598         if ((startcode & 0xFFFFFF00) != 0x100)
2599             continue;  // no startcode
2600
2601         if (s->avctx->debug & FF_DEBUG_STARTCODE) {
2602             av_log(s->avctx, AV_LOG_DEBUG, "startcode: %3X ", startcode);
2603             if (startcode <= 0x11F)
2604                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
2605             else if (startcode <= 0x12F)
2606                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
2607             else if (startcode <= 0x13F)
2608                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2609             else if (startcode <= 0x15F)
2610                 av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
2611             else if (startcode <= 0x1AF)
2612                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2613             else if (startcode == 0x1B0)
2614                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
2615             else if (startcode == 0x1B1)
2616                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
2617             else if (startcode == 0x1B2)
2618                 av_log(s->avctx, AV_LOG_DEBUG, "User Data");
2619             else if (startcode == 0x1B3)
2620                 av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
2621             else if (startcode == 0x1B4)
2622                 av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
2623             else if (startcode == 0x1B5)
2624                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
2625             else if (startcode == 0x1B6)
2626                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
2627             else if (startcode == 0x1B7)
2628                 av_log(s->avctx, AV_LOG_DEBUG, "slice start");
2629             else if (startcode == 0x1B8)
2630                 av_log(s->avctx, AV_LOG_DEBUG, "extension start");
2631             else if (startcode == 0x1B9)
2632                 av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
2633             else if (startcode == 0x1BA)
2634                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
2635             else if (startcode == 0x1BB)
2636                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
2637             else if (startcode == 0x1BC)
2638                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
2639             else if (startcode == 0x1BD)
2640                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
2641             else if (startcode == 0x1BE)
2642                 av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
2643             else if (startcode == 0x1BF)
2644                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
2645             else if (startcode == 0x1C0)
2646                 av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
2647             else if (startcode == 0x1C1)
2648                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
2649             else if (startcode == 0x1C2)
2650                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
2651             else if (startcode == 0x1C3)
2652                 av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
2653             else if (startcode <= 0x1C5)
2654                 av_log(s->avctx, AV_LOG_DEBUG, "reserved");
2655             else if (startcode <= 0x1FF)
2656                 av_log(s->avctx, AV_LOG_DEBUG, "System start");
2657             av_log(s->avctx, AV_LOG_DEBUG, " at %d\n", get_bits_count(gb));
2658         }
2659
2660         if (startcode >= 0x120 && startcode <= 0x12F) {
2661             if (vol) {
2662                 av_log(s->avctx, AV_LOG_ERROR, "Multiple VOL headers");
2663                 return AVERROR_INVALIDDATA;
2664             }
2665             vol++;
2666             if ((ret = decode_vol_header(ctx, gb)) < 0)
2667                 return ret;
2668         } else if (startcode == USER_DATA_STARTCODE) {
2669             decode_user_data(ctx, gb);
2670         } else if (startcode == GOP_STARTCODE) {
2671             mpeg4_decode_gop_header(s, gb);
2672         } else if (startcode == VOS_STARTCODE) {
2673             mpeg4_decode_profile_level(s, gb);
2674         } else if (startcode == VOP_STARTCODE) {
2675             break;
2676         }
2677
2678         align_get_bits(gb);
2679         startcode = 0xff;
2680     }
2681
2682 end:
2683     if (s->avctx->flags & AV_CODEC_FLAG_LOW_DELAY)
2684         s->low_delay = 1;
2685     s->avctx->has_b_frames = !s->low_delay;
2686
2687     return decode_vop_header(ctx, gb);
2688 }
2689
2690 av_cold void ff_mpeg4videodec_static_init(void) {
2691     static int done = 0;
2692
2693     if (!done) {
2694         ff_rl_init(&ff_mpeg4_rl_intra, ff_mpeg4_static_rl_table_store[0]);
2695         ff_rl_init(&ff_rvlc_rl_inter, ff_mpeg4_static_rl_table_store[1]);
2696         ff_rl_init(&ff_rvlc_rl_intra, ff_mpeg4_static_rl_table_store[2]);
2697         INIT_VLC_RL(ff_mpeg4_rl_intra, 554);
2698         INIT_VLC_RL(ff_rvlc_rl_inter, 1072);
2699         INIT_VLC_RL(ff_rvlc_rl_intra, 1072);
2700         INIT_VLC_STATIC(&dc_lum, DC_VLC_BITS, 10 /* 13 */,
2701                         &ff_mpeg4_DCtab_lum[0][1], 2, 1,
2702                         &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
2703         INIT_VLC_STATIC(&dc_chrom, DC_VLC_BITS, 10 /* 13 */,
2704                         &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
2705                         &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
2706         INIT_VLC_STATIC(&sprite_trajectory, SPRITE_TRAJ_VLC_BITS, 15,
2707                         &ff_sprite_trajectory_tab[0][1], 4, 2,
2708                         &ff_sprite_trajectory_tab[0][0], 4, 2, 128);
2709         INIT_VLC_STATIC(&mb_type_b_vlc, MB_TYPE_B_VLC_BITS, 4,
2710                         &ff_mb_type_b_tab[0][1], 2, 1,
2711                         &ff_mb_type_b_tab[0][0], 2, 1, 16);
2712         done = 1;
2713     }
2714 }
2715
2716 int ff_mpeg4_frame_end(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
2717 {
2718     Mpeg4DecContext *ctx = avctx->priv_data;
2719     MpegEncContext    *s = &ctx->m;
2720
2721     /* divx 5.01+ bitstream reorder stuff */
2722     /* Since this clobbers the input buffer and hwaccel codecs still need the
2723      * data during hwaccel->end_frame we should not do this any earlier */
2724     if (s->divx_packed) {
2725         int current_pos     = s->gb.buffer == s->bitstream_buffer ? 0 : (get_bits_count(&s->gb) >> 3);
2726         int startcode_found = 0;
2727
2728         if (buf_size - current_pos > 7) {
2729
2730             int i;
2731             for (i = current_pos; i < buf_size - 4; i++)
2732
2733                 if (buf[i]     == 0 &&
2734                     buf[i + 1] == 0 &&
2735                     buf[i + 2] == 1 &&
2736                     buf[i + 3] == 0xB6) {
2737                     startcode_found = !(buf[i + 4] & 0x40);
2738                     break;
2739                 }
2740         }
2741
2742         if (startcode_found) {
2743             if (!ctx->showed_packed_warning) {
2744                 av_log(s->avctx, AV_LOG_INFO, "Video uses a non-standard and "
2745                        "wasteful way to store B-frames ('packed B-frames'). "
2746                        "Consider using the mpeg4_unpack_bframes bitstream filter without encoding but stream copy to fix it.\n");
2747                 ctx->showed_packed_warning = 1;
2748             }
2749             av_fast_padded_malloc(&s->bitstream_buffer,
2750                            &s->allocated_bitstream_buffer_size,
2751                            buf_size - current_pos);
2752             if (!s->bitstream_buffer) {
2753                 s->bitstream_buffer_size = 0;
2754                 return AVERROR(ENOMEM);
2755             }
2756             memcpy(s->bitstream_buffer, buf + current_pos,
2757                    buf_size - current_pos);
2758             s->bitstream_buffer_size = buf_size - current_pos;
2759         }
2760     }
2761
2762     return 0;
2763 }
2764
2765 #if HAVE_THREADS
2766 static int mpeg4_update_thread_context(AVCodecContext *dst,
2767                                        const AVCodecContext *src)
2768 {
2769     Mpeg4DecContext *s = dst->priv_data;
2770     const Mpeg4DecContext *s1 = src->priv_data;
2771     int init = s->m.context_initialized;
2772
2773     int ret = ff_mpeg_update_thread_context(dst, src);
2774
2775     if (ret < 0)
2776         return ret;
2777
2778     memcpy(((uint8_t*)s) + sizeof(MpegEncContext), ((uint8_t*)s1) + sizeof(MpegEncContext), sizeof(Mpeg4DecContext) - sizeof(MpegEncContext));
2779
2780     if (CONFIG_MPEG4_DECODER && !init && s1->xvid_build >= 0)
2781         ff_xvid_idct_init(&s->m.idsp, dst);
2782
2783     return 0;
2784 }
2785 #endif
2786
2787 static av_cold int decode_init(AVCodecContext *avctx)
2788 {
2789     Mpeg4DecContext *ctx = avctx->priv_data;
2790     MpegEncContext *s = &ctx->m;
2791     int ret;
2792
2793     ctx->divx_version =
2794     ctx->divx_build   =
2795     ctx->xvid_build   =
2796     ctx->lavc_build   = -1;
2797
2798     if ((ret = ff_h263_decode_init(avctx)) < 0)
2799         return ret;
2800
2801     ff_mpeg4videodec_static_init();
2802
2803     s->h263_pred = 1;
2804     s->low_delay = 0; /* default, might be overridden in the vol header during header parsing */
2805     s->decode_mb = mpeg4_decode_mb;
2806     ctx->time_increment_bits = 4; /* default value for broken headers */
2807
2808     avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
2809     avctx->internal->allocate_progress = 1;
2810
2811     return 0;
2812 }
2813
2814 static const AVOption mpeg4_options[] = {
2815     {"quarter_sample", "1/4 subpel MC", offsetof(MpegEncContext, quarter_sample), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, 0},
2816     {"divx_packed", "divx style packed b frames", offsetof(MpegEncContext, divx_packed), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, 0},
2817     {NULL}
2818 };
2819
2820 static const AVClass mpeg4_class = {
2821     "MPEG4 Video Decoder",
2822     av_default_item_name,
2823     mpeg4_options,
2824     LIBAVUTIL_VERSION_INT,
2825 };
2826
2827 AVCodec ff_mpeg4_decoder = {
2828     .name                  = "mpeg4",
2829     .long_name             = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
2830     .type                  = AVMEDIA_TYPE_VIDEO,
2831     .id                    = AV_CODEC_ID_MPEG4,
2832     .priv_data_size        = sizeof(Mpeg4DecContext),
2833     .init                  = decode_init,
2834     .close                 = ff_h263_decode_end,
2835     .decode                = ff_h263_decode_frame,
2836     .capabilities          = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1 |
2837                              AV_CODEC_CAP_TRUNCATED | AV_CODEC_CAP_DELAY |
2838                              AV_CODEC_CAP_FRAME_THREADS,
2839     .caps_internal         = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
2840     .flush                 = ff_mpeg_flush,
2841     .max_lowres            = 3,
2842     .pix_fmts              = ff_h263_hwaccel_pixfmt_list_420,
2843     .profiles              = NULL_IF_CONFIG_SMALL(ff_mpeg4_video_profiles),
2844     .update_thread_context = ONLY_IF_THREADS_ENABLED(mpeg4_update_thread_context),
2845     .priv_class = &mpeg4_class,
2846 };
2847
2848
2849 #if CONFIG_MPEG4_VDPAU_DECODER && FF_API_VDPAU
2850 static const AVClass mpeg4_vdpau_class = {
2851     "MPEG4 Video VDPAU Decoder",
2852     av_default_item_name,
2853     mpeg4_options,
2854     LIBAVUTIL_VERSION_INT,
2855 };
2856
2857 AVCodec ff_mpeg4_vdpau_decoder = {
2858     .name           = "mpeg4_vdpau",
2859     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),
2860     .type           = AVMEDIA_TYPE_VIDEO,
2861     .id             = AV_CODEC_ID_MPEG4,
2862     .priv_data_size = sizeof(Mpeg4DecContext),
2863     .init           = decode_init,
2864     .close          = ff_h263_decode_end,
2865     .decode         = ff_h263_decode_frame,
2866     .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_TRUNCATED | AV_CODEC_CAP_DELAY |
2867                       AV_CODEC_CAP_HWACCEL_VDPAU,
2868     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_VDPAU_MPEG4,
2869                                                   AV_PIX_FMT_NONE },
2870     .priv_class     = &mpeg4_vdpau_class,
2871 };
2872 #endif