libavcodec/mss2.c

   1 /*
   2  * Microsoft Screen 2 (aka Windows Media Video V9 Screen) decoder
   3  *
   4  * This file is part of Libav.
   5  *
   6  * Libav is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * Libav is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with Libav; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * Microsoft Screen 2 (aka Windows Media Video V9 Screen) decoder
  24  */
  25
  26 #include "libavutil/avassert.h"
  27 #include "internal.h"
  28 #include "msmpeg4data.h"
  29 #include "vc1.h"
  30 #include "mss12.h"
  31 #include "mss2dsp.h"
  32
  33 typedef struct MSS2Context {
  34     VC1Context     v;
  35     int            split_position;
  36     AVFrame        pic;
  37     AVFrame        last_pic;
  38     MSS12Context   c;
  39     MSS2DSPContext dsp;
  40     SliceContext   sc[2];
  41 } MSS2Context;
  42
  43 static void arith2_normalise(ArithCoder *c)
  44 {
  45     while ((c->high >> 15) - (c->low >> 15) < 2) {
  46         if ((c->low ^ c->high) & 0x10000) {
  47             c->high  ^= 0x8000;
  48             c->value ^= 0x8000;
  49             c->low   ^= 0x8000;
  50         }
  51         c->high  = c->high  << 8 & 0xFFFFFF | 0xFF;
  52         c->value = c->value << 8 & 0xFFFFFF | bytestream2_get_byte(c->gbc.gB);
  53         c->low   = c->low   << 8 & 0xFFFFFF;
  54     }
  55 }
  56
  57 ARITH_GET_BIT(2)
  58
  59 /* L. Stuiver and A. Moffat: "Piecewise Integer Mapping for Arithmetic Coding."
  60  * In Proc. 8th Data Compression Conference (DCC '98), pp. 3-12, Mar. 1998 */
  61
  62 static int arith2_get_scaled_value(int value, int n, int range)
  63 {
  64     int split = (n << 1) - range;
  65
  66     if (value > split)
  67         return split + (value - split >> 1);
  68     else
  69         return value;
  70 }
  71
  72 static void arith2_rescale_interval(ArithCoder *c, int range,
  73                                     int low, int high, int n)
  74 {
  75     int split = (n << 1) - range;
  76
  77     if (high > split)
  78         c->high = split + (high - split << 1);
  79     else
  80         c->high = high;
  81
  82     c->high += c->low - 1;
  83
  84     if (low > split)
  85         c->low += split + (low - split << 1);
  86     else
  87         c->low += low;
  88 }
  89
  90 static int arith2_get_number(ArithCoder *c, int n)
  91 {
  92     int range = c->high - c->low + 1;
  93     int scale = av_log2(range) - av_log2(n);
  94     int val;
  95
  96     if (n << scale > range)
  97         scale--;
  98
  99     n <<= scale;
 100
 101     val = arith2_get_scaled_value(c->value - c->low, n, range) >> scale;
 102
 103     arith2_rescale_interval(c, range, val << scale, (val + 1) << scale, n);
 104
 105     arith2_normalise(c);
 106
 107     return val;
 108 }
 109
 110 static int arith2_get_prob(ArithCoder *c, int16_t *probs)
 111 {
 112     int range = c->high - c->low + 1, n = *probs;
 113     int scale = av_log2(range) - av_log2(n);
 114     int i     = 0, val;
 115
 116     if (n << scale > range)
 117         scale--;
 118
 119     n <<= scale;
 120
 121     val = arith2_get_scaled_value(c->value - c->low, n, range) >> scale;
 122     while (probs[++i] > val) ;
 123
 124     arith2_rescale_interval(c, range,
 125                             probs[i] << scale, probs[i - 1] << scale, n);
 126
 127     return i;
 128 }
 129
 130 ARITH_GET_MODEL_SYM(2)
 131
 132 static int arith2_get_consumed_bytes(ArithCoder *c)
 133 {
 134     int diff = (c->high >> 16) - (c->low >> 16);
 135     int bp   = bytestream2_tell(c->gbc.gB) - 3 << 3;
 136     int bits = 1;
 137
 138     while (!(diff & 0x80)) {
 139         bits++;
 140         diff <<= 1;
 141     }
 142
 143     return (bits + bp + 7 >> 3) + ((c->low >> 16) + 1 == c->high >> 16);
 144 }
 145
 146 static void arith2_init(ArithCoder *c, GetByteContext *gB)
 147 {
 148     c->low           = 0;
 149     c->high          = 0xFFFFFF;
 150     c->value         = bytestream2_get_be24(gB);
 151     c->gbc.gB        = gB;
 152     c->get_model_sym = arith2_get_model_sym;
 153     c->get_number    = arith2_get_number;
 154 }
 155
 156 static int decode_pal_v2(MSS12Context *ctx, const uint8_t *buf, int buf_size)
 157 {
 158     int i, ncol;
 159     uint32_t *pal = ctx->pal + 256 - ctx->free_colours;
 160
 161     if (!ctx->free_colours)
 162         return 0;
 163
 164     ncol = *buf++;
 165     if (ncol > ctx->free_colours || buf_size < 2 + ncol * 3)
 166         return -1;
 167     for (i = 0; i < ncol; i++)
 168         *pal++ = AV_RB24(buf + 3 * i);
 169
 170     return 1 + ncol * 3;
 171 }
 172
 173 static int decode_555(GetByteContext *gB, uint16_t *dst, int stride,
 174                       int keyframe, int w, int h)
 175 {
 176     int last_symbol = 0, repeat = 0, prev_avail = 0;
 177
 178     if (!keyframe) {
 179         int x, y, endx, endy, t;
 180
 181 #define READ_PAIR(a, b)                 \
 182     a  = bytestream2_get_byte(gB) << 4; \
 183     t  = bytestream2_get_byte(gB);      \
 184     a |= t >> 4;                        \
 185     b  = (t & 0xF) << 8;                \
 186     b |= bytestream2_get_byte(gB);      \
 187
 188         READ_PAIR(x, endx)
 189         READ_PAIR(y, endy)
 190
 191         if (endx >= w || endy >= h || x > endx || y > endy)
 192             return -1;
 193         dst += x + stride * y;
 194         w    = endx - x + 1;
 195         h    = endy - y + 1;
 196         if (y)
 197             prev_avail = 1;
 198     }
 199
 200     do {
 201         uint16_t *p = dst;
 202         do {
 203             if (repeat-- < 1) {
 204                 int b = bytestream2_get_byte(gB);
 205                 if (b < 128)
 206                     last_symbol = b << 8 | bytestream2_get_byte(gB);
 207                 else if (b > 129) {
 208                     repeat = 0;
 209                     while (b-- > 130)
 210                         repeat = (repeat << 8) + bytestream2_get_byte(gB) + 1;
 211                     if (last_symbol == -2) {
 212                         int skip = FFMIN((unsigned)repeat, dst + w - p);
 213                         repeat -= skip;
 214                         p      += skip;
 215                     }
 216                 } else
 217                     last_symbol = 127 - b;
 218             }
 219             if (last_symbol >= 0)
 220                 *p = last_symbol;
 221             else if (last_symbol == -1 && prev_avail)
 222                 *p = *(p - stride);
 223         } while (++p < dst + w);
 224         dst       += stride;
 225         prev_avail = 1;
 226     } while (--h);
 227
 228     return 0;
 229 }
 230
 231 static int decode_rle(GetBitContext *gb, uint8_t *pal_dst, int pal_stride,
 232                       uint8_t *rgb_dst, int rgb_stride, uint32_t *pal,
 233                       int keyframe, int kf_slipt, int slice, int w, int h)
 234 {
 235     uint8_t bits[270] = { 0 };
 236     uint32_t codes[270];
 237     VLC vlc;
 238
 239     int current_length = 0, read_codes = 0, next_code = 0, current_codes = 0;
 240     int remaining_codes, surplus_codes, i;
 241
 242     const int alphabet_size = 270 - keyframe;
 243
 244     int last_symbol = 0, repeat = 0, prev_avail = 0;
 245
 246     if (!keyframe) {
 247         int x, y, clipw, cliph;
 248
 249         x     = get_bits(gb, 12);
 250         y     = get_bits(gb, 12);
 251         clipw = get_bits(gb, 12) + 1;
 252         cliph = get_bits(gb, 12) + 1;
 253
 254         if (x + clipw > w || y + cliph > h)
 255             return AVERROR_INVALIDDATA;
 256         pal_dst += pal_stride * y + x;
 257         rgb_dst += rgb_stride * y + x * 3;
 258         w        = clipw;
 259         h        = cliph;
 260         if (y)
 261             prev_avail = 1;
 262     } else {
 263         if (slice > 0) {
 264             pal_dst   += pal_stride * kf_slipt;
 265             rgb_dst   += rgb_stride * kf_slipt;
 266             prev_avail = 1;
 267             h         -= kf_slipt;
 268         } else
 269             h = kf_slipt;
 270     }
 271
 272     /* read explicit codes */
 273     do {
 274         while (current_codes--) {
 275             int symbol = get_bits(gb, 8);
 276             if (symbol >= 204 - keyframe)
 277                 symbol += 14 - keyframe;
 278             else if (symbol > 189)
 279                 symbol = get_bits1(gb) + (symbol << 1) - 190;
 280             if (bits[symbol])
 281                 return AVERROR_INVALIDDATA;
 282             bits[symbol]  = current_length;
 283             codes[symbol] = next_code++;
 284             read_codes++;
 285         }
 286         current_length++;
 287         next_code     <<= 1;
 288         remaining_codes = (1 << current_length) - next_code;
 289         current_codes   = get_bits(gb, av_ceil_log2(remaining_codes + 1));
 290         if (current_length > 22 || current_codes > remaining_codes)
 291             return AVERROR_INVALIDDATA;
 292     } while (current_codes != remaining_codes);
 293
 294     remaining_codes = alphabet_size - read_codes;
 295
 296     /* determine the minimum length to fit the rest of the alphabet */
 297     while ((surplus_codes = (2 << current_length) -
 298                             (next_code << 1) - remaining_codes) < 0) {
 299         current_length++;
 300         next_code <<= 1;
 301     }
 302
 303     /* add the rest of the symbols lexicographically */
 304     for (i = 0; i < alphabet_size; i++)
 305         if (!bits[i]) {
 306             if (surplus_codes-- == 0) {
 307                 current_length++;
 308                 next_code <<= 1;
 309             }
 310             bits[i]  = current_length;
 311             codes[i] = next_code++;
 312         }
 313
 314     if (next_code != 1 << current_length)
 315         return AVERROR_INVALIDDATA;
 316
 317     if (i = init_vlc(&vlc, 9, alphabet_size, bits, 1, 1, codes, 4, 4, 0))
 318         return i;
 319
 320     /* frame decode */
 321     do {
 322         uint8_t *pp = pal_dst;
 323         uint8_t *rp = rgb_dst;
 324         do {
 325             if (repeat-- < 1) {
 326                 int b = get_vlc2(gb, vlc.table, 9, 3);
 327                 if (b < 256)
 328                     last_symbol = b;
 329                 else if (b < 268) {
 330                     b -= 256;
 331                     if (b == 11)
 332                         b = get_bits(gb, 4) + 10;
 333
 334                     if (!b)
 335                         repeat = 0;
 336                     else
 337                         repeat = get_bits(gb, b);
 338
 339                     repeat += (1 << b) - 1;
 340
 341                     if (last_symbol == -2) {
 342                         int skip = FFMIN(repeat, pal_dst + w - pp);
 343                         repeat -= skip;
 344                         pp     += skip;
 345                         rp     += skip * 3;
 346                     }
 347                 } else
 348                     last_symbol = 267 - b;
 349             }
 350             if (last_symbol >= 0) {
 351                 *pp = last_symbol;
 352                 AV_WB24(rp, pal[last_symbol]);
 353             } else if (last_symbol == -1 && prev_avail) {
 354                 *pp = *(pp - pal_stride);
 355                 memcpy(rp, rp - rgb_stride, 3);
 356             }
 357             rp += 3;
 358         } while (++pp < pal_dst + w);
 359         pal_dst   += pal_stride;
 360         rgb_dst   += rgb_stride;
 361         prev_avail = 1;
 362     } while (--h);
 363
 364     ff_free_vlc(&vlc);
 365     return 0;
 366 }
 367
 368 static int decode_wmv9(AVCodecContext *avctx, const uint8_t *buf, int buf_size,
 369                        int x, int y, int w, int h, int wmv9_mask)
 370 {
 371     MSS2Context *ctx  = avctx->priv_data;
 372     MSS12Context *c   = &ctx->c;
 373     VC1Context *v     = avctx->priv_data;
 374     MpegEncContext *s = &v->s;
 375     AVFrame *f;
 376
 377     ff_mpeg_flush(avctx);
 378
 379     if (s->current_picture_ptr == NULL || s->current_picture_ptr->f.data[0]) {
 380         int i = ff_find_unused_picture(s, 0);
 381         if (i < 0)
 382             return -1;
 383         s->current_picture_ptr = &s->picture[i];
 384     }
 385
 386     init_get_bits(&s->gb, buf, buf_size * 8);
 387
 388     s->loop_filter = avctx->skip_loop_filter < AVDISCARD_ALL;
 389
 390     if (ff_vc1_parse_frame_header(v, &s->gb) == -1) {
 391         av_log(v->s.avctx, AV_LOG_ERROR, "header error\n");
 392         return AVERROR_INVALIDDATA;
 393     }
 394
 395     if (s->pict_type != AV_PICTURE_TYPE_I) {
 396         av_log(v->s.avctx, AV_LOG_ERROR, "expected I-frame\n");
 397         return AVERROR_INVALIDDATA;
 398     }
 399
 400     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
 401
 402     if (ff_MPV_frame_start(s, avctx) < 0) {
 403         av_log(v->s.avctx, AV_LOG_ERROR, "ff_MPV_frame_start error\n");
 404         avctx->pix_fmt = AV_PIX_FMT_RGB24;
 405         return -1;
 406     }
 407
 408     ff_er_frame_start(s);
 409
 410     v->bits = buf_size * 8;
 411
 412     v->end_mb_x = (w + 15) >> 4;
 413     s->end_mb_y = (h + 15) >> 4;
 414     if (v->respic & 1)
 415         v->end_mb_x = v->end_mb_x + 1 >> 1;
 416     if (v->respic & 2)
 417         s->end_mb_y = s->end_mb_y + 1 >> 1;
 418
 419     ff_vc1_decode_blocks(v);
 420
 421     ff_er_frame_end(s);
 422
 423     ff_MPV_frame_end(s);
 424
 425     f = &s->current_picture.f;
 426
 427     if (v->respic == 3) {
 428         ctx->dsp.upsample_plane(f->data[0], f->linesize[0], w,      h);
 429         ctx->dsp.upsample_plane(f->data[1], f->linesize[1], w >> 1, h >> 1);
 430         ctx->dsp.upsample_plane(f->data[2], f->linesize[2], w >> 1, h >> 1);
 431     } else if (v->respic)
 432         av_log_ask_for_sample(v->s.avctx,
 433                               "Asymmetric WMV9 rectangle subsampling\n");
 434
 435     av_assert0(f->linesize[1] == f->linesize[2]);
 436
 437     if (wmv9_mask != -1)
 438         ctx->dsp.mss2_blit_wmv9_masked(c->rgb_pic + y * c->rgb_stride + x * 3,
 439                                        c->rgb_stride, wmv9_mask,
 440                                        c->pal_pic + y * c->pal_stride + x,
 441                                        c->pal_stride,
 442                                        f->data[0], f->linesize[0],
 443                                        f->data[1], f->data[2], f->linesize[1],
 444                                        w, h);
 445     else
 446         ctx->dsp.mss2_blit_wmv9(c->rgb_pic + y * c->rgb_stride + x * 3,
 447                                 c->rgb_stride,
 448                                 f->data[0], f->linesize[0],
 449                                 f->data[1], f->data[2], f->linesize[1],
 450                                 w, h);
 451
 452     avctx->pix_fmt = AV_PIX_FMT_RGB24;
 453
 454     return 0;
 455 }
 456
 457 typedef struct Rectangle {
 458     int coded, x, y, w, h;
 459 } Rectangle;
 460
 461 #define MAX_WMV9_RECTANGLES 20
 462 #define ARITH2_PADDING 2
 463
 464 static int mss2_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
 465                              AVPacket *avpkt)
 466 {
 467     const uint8_t *buf = avpkt->data;
 468     int buf_size       = avpkt->size;
 469     MSS2Context *ctx = avctx->priv_data;
 470     MSS12Context *c  = &ctx->c;
 471     GetBitContext gb;
 472     GetByteContext gB;
 473     ArithCoder acoder;
 474
 475     int keyframe, has_wmv9, has_mv, is_rle, is_555, ret;
 476
 477     Rectangle wmv9rects[MAX_WMV9_RECTANGLES], *r;
 478     int used_rects = 0, i, implicit_rect = 0, av_uninit(wmv9_mask);
 479
 480     av_assert0(FF_INPUT_BUFFER_PADDING_SIZE >=
 481                ARITH2_PADDING + (MIN_CACHE_BITS + 7) / 8);
 482
 483     init_get_bits(&gb, buf, buf_size * 8);
 484
 485     if (keyframe = get_bits1(&gb))
 486         skip_bits(&gb, 7);
 487     has_wmv9 = get_bits1(&gb);
 488     has_mv   = keyframe ? 0 : get_bits1(&gb);
 489     is_rle   = get_bits1(&gb);
 490     is_555   = is_rle && get_bits1(&gb);
 491     if (c->slice_split > 0)
 492         ctx->split_position = c->slice_split;
 493     else if (c->slice_split < 0) {
 494         if (get_bits1(&gb)) {
 495             if (get_bits1(&gb)) {
 496                 if (get_bits1(&gb))
 497                     ctx->split_position = get_bits(&gb, 16);
 498                 else
 499                     ctx->split_position = get_bits(&gb, 12);
 500             } else
 501                 ctx->split_position = get_bits(&gb, 8) << 4;
 502         } else {
 503             if (keyframe)
 504                 ctx->split_position = avctx->height / 2;
 505         }
 506     } else
 507         ctx->split_position = avctx->height;
 508
 509     if (c->slice_split && (ctx->split_position < 1 - is_555 ||
 510                            ctx->split_position > avctx->height - 1))
 511         return AVERROR_INVALIDDATA;
 512
 513     align_get_bits(&gb);
 514     buf      += get_bits_count(&gb) >> 3;
 515     buf_size -= get_bits_count(&gb) >> 3;
 516
 517     if (buf_size < 1)
 518         return AVERROR_INVALIDDATA;
 519
 520     if (is_555 && (has_wmv9 || has_mv || c->slice_split && ctx->split_position))
 521         return AVERROR_INVALIDDATA;
 522
 523     avctx->pix_fmt = is_555 ? AV_PIX_FMT_RGB555 : AV_PIX_FMT_RGB24;
 524     if (ctx->pic.data[0] && ctx->pic.format != avctx->pix_fmt)
 525         avctx->release_buffer(avctx, &ctx->pic);
 526
 527     if (has_wmv9) {
 528         bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
 529         arith2_init(&acoder, &gB);
 530
 531         implicit_rect = !arith2_get_bit(&acoder);
 532
 533         while (arith2_get_bit(&acoder)) {
 534             if (used_rects == MAX_WMV9_RECTANGLES)
 535                 return AVERROR_INVALIDDATA;
 536             r = &wmv9rects[used_rects];
 537             if (!used_rects)
 538                 r->x = arith2_get_number(&acoder, avctx->width);
 539             else
 540                 r->x = arith2_get_number(&acoder, avctx->width -
 541                                          wmv9rects[used_rects - 1].x) +
 542                        wmv9rects[used_rects - 1].x;
 543             r->y = arith2_get_number(&acoder, avctx->height);
 544             r->w = arith2_get_number(&acoder, avctx->width  - r->x) + 1;
 545             r->h = arith2_get_number(&acoder, avctx->height - r->y) + 1;
 546             used_rects++;
 547         }
 548
 549         if (implicit_rect && used_rects) {
 550             av_log(avctx, AV_LOG_ERROR, "implicit_rect && used_rects > 0\n");
 551             return AVERROR_INVALIDDATA;
 552         }
 553
 554         if (implicit_rect) {
 555             wmv9rects[0].x = 0;
 556             wmv9rects[0].y = 0;
 557             wmv9rects[0].w = avctx->width;
 558             wmv9rects[0].h = avctx->height;
 559
 560             used_rects = 1;
 561         }
 562         for (i = 0; i < used_rects; i++) {
 563             if (!implicit_rect && arith2_get_bit(&acoder)) {
 564                 av_log(avctx, AV_LOG_ERROR, "Unexpected grandchildren\n");
 565                 return AVERROR_INVALIDDATA;
 566             }
 567             if (!i) {
 568                 wmv9_mask = arith2_get_bit(&acoder) - 1;
 569                 if (!wmv9_mask)
 570                     wmv9_mask = arith2_get_number(&acoder, 256);
 571             }
 572             wmv9rects[i].coded = arith2_get_number(&acoder, 2);
 573         }
 574
 575         buf      += arith2_get_consumed_bytes(&acoder);
 576         buf_size -= arith2_get_consumed_bytes(&acoder);
 577         if (buf_size < 1)
 578             return AVERROR_INVALIDDATA;
 579     }
 580
 581     c->mvX = c->mvY = 0;
 582     if (keyframe && !is_555) {
 583         if ((i = decode_pal_v2(c, buf, buf_size)) < 0)
 584             return AVERROR_INVALIDDATA;
 585         buf      += i;
 586         buf_size -= i;
 587     } else if (has_mv) {
 588         buf      += 4;
 589         buf_size -= 4;
 590         if (buf_size < 1)
 591             return AVERROR_INVALIDDATA;
 592         c->mvX = AV_RB16(buf - 4) - avctx->width;
 593         c->mvY = AV_RB16(buf - 2) - avctx->height;
 594     }
 595
 596     if (c->mvX < 0 || c->mvY < 0) {
 597         FFSWAP(AVFrame, ctx->pic, ctx->last_pic);
 598         FFSWAP(uint8_t *, c->pal_pic, c->last_pal_pic);
 599
 600         if (ctx->pic.data[0])
 601             avctx->release_buffer(avctx, &ctx->pic);
 602
 603         ctx->pic.reference    = 3;
 604         ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID    |
 605                                 FF_BUFFER_HINTS_READABLE |
 606                                 FF_BUFFER_HINTS_PRESERVE |
 607                                 FF_BUFFER_HINTS_REUSABLE;
 608
 609         if ((ret = ff_get_buffer(avctx, &ctx->pic)) < 0) {
 610             av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 611             return ret;
 612         }
 613
 614         if (ctx->last_pic.data[0]) {
 615             av_assert0(ctx->pic.linesize[0] == ctx->last_pic.linesize[0]);
 616             c->last_rgb_pic = ctx->last_pic.data[0] +
 617                               ctx->last_pic.linesize[0] * (avctx->height - 1);
 618         } else {
 619             av_log(avctx, AV_LOG_ERROR, "Missing keyframe\n");
 620             return -1;
 621         }
 622     } else {
 623         if (ctx->last_pic.data[0])
 624             avctx->release_buffer(avctx, &ctx->last_pic);
 625
 626         ctx->pic.reference    = 3;
 627         ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID    |
 628                                 FF_BUFFER_HINTS_READABLE |
 629                                 FF_BUFFER_HINTS_PRESERVE |
 630                                 FF_BUFFER_HINTS_REUSABLE;
 631
 632         if ((ret = avctx->reget_buffer(avctx, &ctx->pic)) < 0) {
 633             av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 634             return ret;
 635         }
 636
 637         c->last_rgb_pic = NULL;
 638     }
 639     c->rgb_pic    = ctx->pic.data[0] +
 640                     ctx->pic.linesize[0] * (avctx->height - 1);
 641     c->rgb_stride = -ctx->pic.linesize[0];
 642
 643     ctx->pic.key_frame = keyframe;
 644     ctx->pic.pict_type = keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
 645
 646     if (is_555) {
 647         bytestream2_init(&gB, buf, buf_size);
 648
 649         if (decode_555(&gB, (uint16_t *)c->rgb_pic, c->rgb_stride >> 1,
 650                        keyframe, avctx->width, avctx->height))
 651             return AVERROR_INVALIDDATA;
 652
 653         buf_size -= bytestream2_tell(&gB);
 654     } else {
 655         if (keyframe) {
 656             c->corrupted = 0;
 657             ff_mss12_slicecontext_reset(&ctx->sc[0]);
 658             if (c->slice_split)
 659                 ff_mss12_slicecontext_reset(&ctx->sc[1]);
 660         }
 661         if (is_rle) {
 662             init_get_bits(&gb, buf, buf_size * 8);
 663             if (ret = decode_rle(&gb, c->pal_pic, c->pal_stride,
 664                                  c->rgb_pic, c->rgb_stride, c->pal, keyframe,
 665                                  ctx->split_position, 0,
 666                                  avctx->width, avctx->height))
 667                 return ret;
 668             align_get_bits(&gb);
 669
 670             if (c->slice_split)
 671                 if (ret = decode_rle(&gb, c->pal_pic, c->pal_stride,
 672                                      c->rgb_pic, c->rgb_stride, c->pal, keyframe,
 673                                      ctx->split_position, 1,
 674                                      avctx->width, avctx->height))
 675                     return ret;
 676
 677             align_get_bits(&gb);
 678             buf      += get_bits_count(&gb) >> 3;
 679             buf_size -= get_bits_count(&gb) >> 3;
 680         } else if (!implicit_rect || wmv9_mask != -1) {
 681             if (c->corrupted)
 682                 return AVERROR_INVALIDDATA;
 683             bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
 684             arith2_init(&acoder, &gB);
 685             c->keyframe = keyframe;
 686             if (c->corrupted = ff_mss12_decode_rect(&ctx->sc[0], &acoder, 0, 0,
 687                                                     avctx->width,
 688                                                     ctx->split_position))
 689                 return AVERROR_INVALIDDATA;
 690
 691             buf      += arith2_get_consumed_bytes(&acoder);
 692             buf_size -= arith2_get_consumed_bytes(&acoder);
 693             if (c->slice_split) {
 694                 if (buf_size < 1)
 695                     return AVERROR_INVALIDDATA;
 696                 bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
 697                 arith2_init(&acoder, &gB);
 698                 if (c->corrupted = ff_mss12_decode_rect(&ctx->sc[1], &acoder, 0,
 699                                                         ctx->split_position,
 700                                                         avctx->width,
 701                                                         avctx->height - ctx->split_position))
 702                     return AVERROR_INVALIDDATA;
 703
 704                 buf      += arith2_get_consumed_bytes(&acoder);
 705                 buf_size -= arith2_get_consumed_bytes(&acoder);
 706             }
 707         } else
 708             memset(c->pal_pic, 0, c->pal_stride * avctx->height);
 709     }
 710
 711     if (has_wmv9) {
 712         for (i = 0; i < used_rects; i++) {
 713             int x = wmv9rects[i].x;
 714             int y = wmv9rects[i].y;
 715             int w = wmv9rects[i].w;
 716             int h = wmv9rects[i].h;
 717             if (wmv9rects[i].coded) {
 718                 int WMV9codedFrameSize;
 719                 if (buf_size < 4 || !(WMV9codedFrameSize = AV_RL24(buf)))
 720                     return AVERROR_INVALIDDATA;
 721                 if (ret = decode_wmv9(avctx, buf + 3, buf_size - 3,
 722                                       x, y, w, h, wmv9_mask))
 723                     return ret;
 724                 buf      += WMV9codedFrameSize + 3;
 725                 buf_size -= WMV9codedFrameSize + 3;
 726             } else {
 727                 uint8_t *dst = c->rgb_pic + y * c->rgb_stride + x * 3;
 728                 if (wmv9_mask != -1) {
 729                     ctx->dsp.mss2_gray_fill_masked(dst, c->rgb_stride,
 730                                                    wmv9_mask,
 731                                                    c->pal_pic + y * c->pal_stride + x,
 732                                                    c->pal_stride,
 733                                                    w, h);
 734                 } else {
 735                     do {
 736                         memset(dst, 0x80, w * 3);
 737                         dst += c->rgb_stride;
 738                     } while (--h);
 739                 }
 740             }
 741         }
 742     }
 743
 744     if (buf_size)
 745         av_log(avctx, AV_LOG_WARNING, "buffer not fully consumed\n");
 746
 747     *got_frame       = 1;
 748     *(AVFrame *)data = ctx->pic;
 749
 750     return avpkt->size;
 751 }
 752
 753 static av_cold int wmv9_init(AVCodecContext *avctx)
 754 {
 755     VC1Context *v = avctx->priv_data;
 756
 757     v->s.avctx    = avctx;
 758     avctx->flags |= CODEC_FLAG_EMU_EDGE;
 759     v->s.flags   |= CODEC_FLAG_EMU_EDGE;
 760
 761     if (avctx->idct_algo == FF_IDCT_AUTO)
 762         avctx->idct_algo = FF_IDCT_WMV2;
 763
 764     if (ff_vc1_init_common(v) < 0)
 765         return -1;
 766     ff_vc1dsp_init(&v->vc1dsp);
 767
 768     v->profile = PROFILE_MAIN;
 769
 770     v->zz_8x4     = ff_wmv2_scantableA;
 771     v->zz_4x8     = ff_wmv2_scantableB;
 772     v->res_y411   = 0;
 773     v->res_sprite = 0;
 774
 775     v->frmrtq_postproc = 7;
 776     v->bitrtq_postproc = 31;
 777
 778     v->res_x8          = 0;
 779     v->multires        = 0;
 780     v->res_fasttx      = 1;
 781
 782     v->fastuvmc        = 0;
 783
 784     v->extended_mv     = 0;
 785
 786     v->dquant          = 1;
 787     v->vstransform     = 1;
 788
 789     v->res_transtab    = 0;
 790
 791     v->overlap         = 0;
 792
 793     v->s.resync_marker = 0;
 794     v->rangered        = 0;
 795
 796     v->s.max_b_frames = avctx->max_b_frames = 0;
 797     v->quantizer_mode = 0;
 798
 799     v->finterpflag = 0;
 800
 801     v->res_rtm_flag = 1;
 802
 803     ff_vc1_init_transposed_scantables(v);
 804
 805     if (ff_msmpeg4_decode_init(avctx) < 0 ||
 806         ff_vc1_decode_init_alloc_tables(v) < 0)
 807         return -1;
 808
 809     /* error concealment */
 810     v->s.me.qpel_put = v->s.dsp.put_qpel_pixels_tab;
 811     v->s.me.qpel_avg = v->s.dsp.avg_qpel_pixels_tab;
 812
 813     return 0;
 814 }
 815
 816 static av_cold int mss2_decode_end(AVCodecContext *avctx)
 817 {
 818     MSS2Context *const ctx = avctx->priv_data;
 819
 820     if (ctx->pic.data[0])
 821         avctx->release_buffer(avctx, &ctx->pic);
 822     if (ctx->last_pic.data[0])
 823         avctx->release_buffer(avctx, &ctx->last_pic);
 824
 825     ff_mss12_decode_end(&ctx->c);
 826     av_freep(&ctx->c.pal_pic);
 827     av_freep(&ctx->c.last_pal_pic);
 828     ff_vc1_decode_end(avctx);
 829
 830     return 0;
 831 }
 832
 833 static av_cold int mss2_decode_init(AVCodecContext *avctx)
 834 {
 835     MSS2Context * const ctx = avctx->priv_data;
 836     MSS12Context *c = &ctx->c;
 837     int ret;
 838     c->avctx = avctx;
 839     avctx->coded_frame = &ctx->pic;
 840     if (ret = ff_mss12_decode_init(c, 1, &ctx->sc[0], &ctx->sc[1]))
 841         return ret;
 842     c->pal_stride   = c->mask_stride;
 843     c->pal_pic      = av_mallocz(c->pal_stride * avctx->height);
 844     c->last_pal_pic = av_mallocz(c->pal_stride * avctx->height);
 845     if (!c->pal_pic || !c->last_pal_pic) {
 846         mss2_decode_end(avctx);
 847         return AVERROR(ENOMEM);
 848     }
 849     if (ret = wmv9_init(avctx)) {
 850         mss2_decode_end(avctx);
 851         return ret;
 852     }
 853     ff_mss2dsp_init(&ctx->dsp);
 854
 855     avctx->pix_fmt = c->free_colours == 127 ? AV_PIX_FMT_RGB555
 856                                             : AV_PIX_FMT_RGB24;
 857
 858     return 0;
 859 }
 860
 861 AVCodec ff_mss2_decoder = {
 862     .name           = "mss2",
 863     .type           = AVMEDIA_TYPE_VIDEO,
 864     .id             = AV_CODEC_ID_MSS2,
 865     .priv_data_size = sizeof(MSS2Context),
 866     .init           = mss2_decode_init,
 867     .close          = mss2_decode_end,
 868     .decode         = mss2_decode_frame,
 869     .capabilities   = CODEC_CAP_DR1,
 870     .long_name      = NULL_IF_CONFIG_SMALL("MS Windows Media Video V9 Screen"),
 871 };