libavcodec/vp56.c

   1 /**
   2  * @file vp56.c
   3  * VP5 and VP6 compatible video decoder (common features)
   4  *
   5  * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #include "avcodec.h"
  25 #include "bytestream.h"
  26
  27 #include "vp56.h"
  28 #include "vp56data.h"
  29
  30
  31 void vp56_init_dequant(vp56_context_t *s, int quantizer)
  32 {
  33     s->quantizer = quantizer;
  34     s->dequant_dc = vp56_dc_dequant[quantizer] << 2;
  35     s->dequant_ac = vp56_ac_dequant[quantizer] << 2;
  36 }
  37
  38 static int vp56_get_vectors_predictors(vp56_context_t *s, int row, int col,
  39                                        vp56_frame_t ref_frame)
  40 {
  41     int nb_pred = 0;
  42     vp56_mv_t vect[2] = {{0,0}, {0,0}};
  43     int pos, offset;
  44     vp56_mv_t mvp;
  45
  46     for (pos=0; pos<12; pos++) {
  47         mvp.x = col + vp56_candidate_predictor_pos[pos][0];
  48         mvp.y = row + vp56_candidate_predictor_pos[pos][1];
  49         if (mvp.x < 0 || mvp.x >= s->mb_width ||
  50             mvp.y < 0 || mvp.y >= s->mb_height)
  51             continue;
  52         offset = mvp.x + s->mb_width*mvp.y;
  53
  54         if (vp56_reference_frame[s->macroblocks[offset].type] != ref_frame)
  55             continue;
  56         if ((s->macroblocks[offset].mv.x == vect[0].x &&
  57              s->macroblocks[offset].mv.y == vect[0].y) ||
  58             (s->macroblocks[offset].mv.x == 0 &&
  59              s->macroblocks[offset].mv.y == 0))
  60             continue;
  61
  62         vect[nb_pred++] = s->macroblocks[offset].mv;
  63         if (nb_pred > 1) {
  64             nb_pred = -1;
  65             break;
  66         }
  67         s->vector_candidate_pos = pos;
  68     }
  69
  70     s->vector_candidate[0] = vect[0];
  71     s->vector_candidate[1] = vect[1];
  72
  73     return nb_pred+1;
  74 }
  75
  76 static void vp56_parse_mb_type_models(vp56_context_t *s)
  77 {
  78     vp56_range_coder_t *c = &s->c;
  79     vp56_model_t *model = s->modelp;
  80     int i, ctx, type;
  81
  82     for (ctx=0; ctx<3; ctx++) {
  83         if (vp56_rac_get_prob(c, 174)) {
  84             int idx = vp56_rac_gets(c, 4);
  85             memcpy(model->mb_types_stats[ctx],
  86                    vp56_pre_def_mb_type_stats[idx][ctx],
  87                    sizeof(model->mb_types_stats[ctx]));
  88         }
  89         if (vp56_rac_get_prob(c, 254)) {
  90             for (type=0; type<10; type++) {
  91                 for(i=0; i<2; i++) {
  92                     if (vp56_rac_get_prob(c, 205)) {
  93                         int delta, sign = vp56_rac_get(c);
  94
  95                         delta = vp56_rac_get_tree(c, vp56_pmbtm_tree,
  96                                                   vp56_mb_type_model_model);
  97                         if (!delta)
  98                             delta = 4 * vp56_rac_gets(c, 7);
  99                         model->mb_types_stats[ctx][type][i] += (delta ^ -sign) + sign;
 100                     }
 101                 }
 102             }
 103         }
 104     }
 105
 106     /* compute MB type probability tables based on previous MB type */
 107     for (ctx=0; ctx<3; ctx++) {
 108         int p[10];
 109
 110         for (type=0; type<10; type++)
 111             p[type] = 100 * model->mb_types_stats[ctx][type][1];
 112
 113         for (type=0; type<10; type++) {
 114             int p02, p34, p0234, p17, p56, p89, p5689, p156789;
 115
 116             /* conservative MB type probability */
 117             model->mb_type[ctx][type][0] = 255 - (255 * model->mb_types_stats[ctx][type][0]) / (1 + model->mb_types_stats[ctx][type][0] + model->mb_types_stats[ctx][type][1]);
 118
 119             p[type] = 0;    /* same MB type => weight is null */
 120
 121             /* binary tree parsing probabilities */
 122             p02 = p[0] + p[2];
 123             p34 = p[3] + p[4];
 124             p0234 = p02 + p34;
 125             p17 = p[1] + p[7];
 126             p56 = p[5] + p[6];
 127             p89 = p[8] + p[9];
 128             p5689 = p56 + p89;
 129             p156789 = p17 + p5689;
 130
 131             model->mb_type[ctx][type][1] = 1 + 255 * p0234/(1+p0234+p156789);
 132             model->mb_type[ctx][type][2] = 1 + 255 * p02  / (1+p0234);
 133             model->mb_type[ctx][type][3] = 1 + 255 * p17  / (1+p156789);
 134             model->mb_type[ctx][type][4] = 1 + 255 * p[0] / (1+p02);
 135             model->mb_type[ctx][type][5] = 1 + 255 * p[3] / (1+p34);
 136             model->mb_type[ctx][type][6] = 1 + 255 * p[1] / (1+p17);
 137             model->mb_type[ctx][type][7] = 1 + 255 * p56  / (1+p5689);
 138             model->mb_type[ctx][type][8] = 1 + 255 * p[5] / (1+p56);
 139             model->mb_type[ctx][type][9] = 1 + 255 * p[8] / (1+p89);
 140
 141             /* restore initial value */
 142             p[type] = 100 * model->mb_types_stats[ctx][type][1];
 143         }
 144     }
 145 }
 146
 147 static vp56_mb_t vp56_parse_mb_type(vp56_context_t *s,
 148                                     vp56_mb_t prev_type, int ctx)
 149 {
 150     uint8_t *mb_type_model = s->modelp->mb_type[ctx][prev_type];
 151     vp56_range_coder_t *c = &s->c;
 152
 153     if (vp56_rac_get_prob(c, mb_type_model[0]))
 154         return prev_type;
 155     else
 156         return vp56_rac_get_tree(c, vp56_pmbt_tree, mb_type_model);
 157 }
 158
 159 static void vp56_decode_4mv(vp56_context_t *s, int row, int col)
 160 {
 161     vp56_mv_t mv = {0,0};
 162     int type[4];
 163     int b;
 164
 165     /* parse each block type */
 166     for (b=0; b<4; b++) {
 167         type[b] = vp56_rac_gets(&s->c, 2);
 168         if (type[b])
 169             type[b]++;  /* only returns 0, 2, 3 or 4 (all INTER_PF) */
 170     }
 171
 172     /* get vectors */
 173     for (b=0; b<4; b++) {
 174         switch (type[b]) {
 175             case VP56_MB_INTER_NOVEC_PF:
 176                 s->mv[b] = (vp56_mv_t) {0,0};
 177                 break;
 178             case VP56_MB_INTER_DELTA_PF:
 179                 s->parse_vector_adjustment(s, &s->mv[b]);
 180                 break;
 181             case VP56_MB_INTER_V1_PF:
 182                 s->mv[b] = s->vector_candidate[0];
 183                 break;
 184             case VP56_MB_INTER_V2_PF:
 185                 s->mv[b] = s->vector_candidate[1];
 186                 break;
 187         }
 188         mv.x += s->mv[b].x;
 189         mv.y += s->mv[b].y;
 190     }
 191
 192     /* this is the one selected for the whole MB for prediction */
 193     s->macroblocks[row * s->mb_width + col].mv = s->mv[3];
 194
 195     /* chroma vectors are average luma vectors */
 196     if (s->avctx->codec->id == CODEC_ID_VP5) {
 197         s->mv[4].x = s->mv[5].x = RSHIFT(mv.x,2);
 198         s->mv[4].y = s->mv[5].y = RSHIFT(mv.y,2);
 199     } else {
 200         s->mv[4] = s->mv[5] = (vp56_mv_t) {mv.x/4, mv.y/4};
 201     }
 202 }
 203
 204 static vp56_mb_t vp56_decode_mv(vp56_context_t *s, int row, int col)
 205 {
 206     vp56_mv_t *mv, vect = {0,0};
 207     int ctx, b;
 208
 209     ctx = vp56_get_vectors_predictors(s, row, col, VP56_FRAME_PREVIOUS);
 210     s->mb_type = vp56_parse_mb_type(s, s->mb_type, ctx);
 211     s->macroblocks[row * s->mb_width + col].type = s->mb_type;
 212
 213     switch (s->mb_type) {
 214         case VP56_MB_INTER_V1_PF:
 215             mv = &s->vector_candidate[0];
 216             break;
 217
 218         case VP56_MB_INTER_V2_PF:
 219             mv = &s->vector_candidate[1];
 220             break;
 221
 222         case VP56_MB_INTER_V1_GF:
 223             vp56_get_vectors_predictors(s, row, col, VP56_FRAME_GOLDEN);
 224             mv = &s->vector_candidate[0];
 225             break;
 226
 227         case VP56_MB_INTER_V2_GF:
 228             vp56_get_vectors_predictors(s, row, col, VP56_FRAME_GOLDEN);
 229             mv = &s->vector_candidate[1];
 230             break;
 231
 232         case VP56_MB_INTER_DELTA_PF:
 233             s->parse_vector_adjustment(s, &vect);
 234             mv = &vect;
 235             break;
 236
 237         case VP56_MB_INTER_DELTA_GF:
 238             vp56_get_vectors_predictors(s, row, col, VP56_FRAME_GOLDEN);
 239             s->parse_vector_adjustment(s, &vect);
 240             mv = &vect;
 241             break;
 242
 243         case VP56_MB_INTER_4V:
 244             vp56_decode_4mv(s, row, col);
 245             return s->mb_type;
 246
 247         default:
 248             mv = &vect;
 249             break;
 250     }
 251
 252     s->macroblocks[row*s->mb_width + col].mv = *mv;
 253
 254     /* same vector for all blocks */
 255     for (b=0; b<6; b++)
 256         s->mv[b] = *mv;
 257
 258     return s->mb_type;
 259 }
 260
 261 static void vp56_add_predictors_dc(vp56_context_t *s, vp56_frame_t ref_frame)
 262 {
 263     int idx = s->scantable.permutated[0];
 264     int b;
 265
 266     for (b=0; b<6; b++) {
 267         vp56_ref_dc_t *ab = &s->above_blocks[s->above_block_idx[b]];
 268         vp56_ref_dc_t *lb = &s->left_block[vp56_b6to4[b]];
 269         int count = 0;
 270         int dc = 0;
 271         int i;
 272
 273         if (ref_frame == lb->ref_frame) {
 274             dc += lb->dc_coeff;
 275             count++;
 276         }
 277         if (ref_frame == ab->ref_frame) {
 278             dc += ab->dc_coeff;
 279             count++;
 280         }
 281         if (s->avctx->codec->id == CODEC_ID_VP5)
 282             for (i=0; i<2; i++)
 283                 if (count < 2 && ref_frame == ab[-1+2*i].ref_frame) {
 284                     dc += ab[-1+2*i].dc_coeff;
 285                     count++;
 286                 }
 287         if (count == 0)
 288             dc = s->prev_dc[vp56_b2p[b]][ref_frame];
 289         else if (count == 2)
 290             dc /= 2;
 291
 292         s->block_coeff[b][idx] += dc;
 293         s->prev_dc[vp56_b2p[b]][ref_frame] = s->block_coeff[b][idx];
 294         ab->dc_coeff = s->block_coeff[b][idx];
 295         ab->ref_frame = ref_frame;
 296         lb->dc_coeff = s->block_coeff[b][idx];
 297         lb->ref_frame = ref_frame;
 298         s->block_coeff[b][idx] *= s->dequant_dc;
 299     }
 300 }
 301
 302 static void vp56_edge_filter(vp56_context_t *s, uint8_t *yuv,
 303                              int pix_inc, int line_inc, int t)
 304 {
 305     int pix2_inc = 2 * pix_inc;
 306     int i, v;
 307
 308     for (i=0; i<12; i++) {
 309         v = (yuv[-pix2_inc] + 3*(yuv[0]-yuv[-pix_inc]) - yuv[pix_inc] + 4) >>3;
 310         v = s->adjust(v, t);
 311         yuv[-pix_inc] = av_clip_uint8(yuv[-pix_inc] + v);
 312         yuv[0] = av_clip_uint8(yuv[0] - v);
 313         yuv += line_inc;
 314     }
 315 }
 316
 317 static void vp56_deblock_filter(vp56_context_t *s, uint8_t *yuv,
 318                                 int stride, int dx, int dy)
 319 {
 320     int t = vp56_filter_threshold[s->quantizer];
 321     if (dx)  vp56_edge_filter(s, yuv +         10-dx ,      1, stride, t);
 322     if (dy)  vp56_edge_filter(s, yuv + stride*(10-dy), stride,      1, t);
 323 }
 324
 325 static void vp56_mc(vp56_context_t *s, int b, int plane, uint8_t *src,
 326                     int stride, int x, int y)
 327 {
 328     uint8_t *dst=s->framep[VP56_FRAME_CURRENT]->data[plane]+s->block_offset[b];
 329     uint8_t *src_block;
 330     int src_offset;
 331     int overlap_offset = 0;
 332     int mask = s->vp56_coord_div[b] - 1;
 333     int deblock_filtering = s->deblock_filtering;
 334     int dx;
 335     int dy;
 336
 337     if (s->avctx->skip_loop_filter >= AVDISCARD_ALL ||
 338         (s->avctx->skip_loop_filter >= AVDISCARD_NONKEY
 339          && !s->framep[VP56_FRAME_CURRENT]->key_frame))
 340         deblock_filtering = 0;
 341
 342     dx = s->mv[b].x / s->vp56_coord_div[b];
 343     dy = s->mv[b].y / s->vp56_coord_div[b];
 344
 345     if (b >= 4) {
 346         x /= 2;
 347         y /= 2;
 348     }
 349     x += dx - 2;
 350     y += dy - 2;
 351
 352     if (x<0 || x+12>=s->plane_width[plane] ||
 353         y<0 || y+12>=s->plane_height[plane]) {
 354         ff_emulated_edge_mc(s->edge_emu_buffer,
 355                             src + s->block_offset[b] + (dy-2)*stride + (dx-2),
 356                             stride, 12, 12, x, y,
 357                             s->plane_width[plane],
 358                             s->plane_height[plane]);
 359         src_block = s->edge_emu_buffer;
 360         src_offset = 2 + 2*stride;
 361     } else if (deblock_filtering) {
 362         /* only need a 12x12 block, but there is no such dsp function, */
 363         /* so copy a 16x12 block */
 364         s->dsp.put_pixels_tab[0][0](s->edge_emu_buffer,
 365                                     src + s->block_offset[b] + (dy-2)*stride + (dx-2),
 366                                     stride, 12);
 367         src_block = s->edge_emu_buffer;
 368         src_offset = 2 + 2*stride;
 369     } else {
 370         src_block = src;
 371         src_offset = s->block_offset[b] + dy*stride + dx;
 372     }
 373
 374     if (deblock_filtering)
 375         vp56_deblock_filter(s, src_block, stride, dx&7, dy&7);
 376
 377     if (s->mv[b].x & mask)
 378         overlap_offset += (s->mv[b].x > 0) ? 1 : -1;
 379     if (s->mv[b].y & mask)
 380         overlap_offset += (s->mv[b].y > 0) ? stride : -stride;
 381
 382     if (overlap_offset) {
 383         if (s->filter)
 384             s->filter(s, dst, src_block, src_offset, src_offset+overlap_offset,
 385                       stride, s->mv[b], mask, s->filter_selection, b<4);
 386         else
 387             s->dsp.put_no_rnd_pixels_l2[1](dst, src_block+src_offset,
 388                                            src_block+src_offset+overlap_offset,
 389                                            stride, 8);
 390     } else {
 391         s->dsp.put_pixels_tab[1][0](dst, src_block+src_offset, stride, 8);
 392     }
 393 }
 394
 395 static void vp56_decode_mb(vp56_context_t *s, int row, int col, int is_alpha)
 396 {
 397     AVFrame *frame_current, *frame_ref;
 398     vp56_mb_t mb_type;
 399     vp56_frame_t ref_frame;
 400     int b, ab, b_max, plane, off;
 401
 402     if (s->framep[VP56_FRAME_CURRENT]->key_frame)
 403         mb_type = VP56_MB_INTRA;
 404     else
 405         mb_type = vp56_decode_mv(s, row, col);
 406     ref_frame = vp56_reference_frame[mb_type];
 407
 408     memset(s->block_coeff, 0, sizeof(s->block_coeff));
 409
 410     s->parse_coeff(s);
 411
 412     vp56_add_predictors_dc(s, ref_frame);
 413
 414     frame_current = s->framep[VP56_FRAME_CURRENT];
 415     frame_ref = s->framep[ref_frame];
 416
 417     ab = 6*is_alpha;
 418     b_max = 6 - 2*is_alpha;
 419
 420     switch (mb_type) {
 421         case VP56_MB_INTRA:
 422             for (b=0; b<b_max; b++) {
 423                 plane = vp56_b2p[b+ab];
 424                 s->dsp.idct_put(frame_current->data[plane] + s->block_offset[b],
 425                                 s->stride[plane], s->block_coeff[b]);
 426             }
 427             break;
 428
 429         case VP56_MB_INTER_NOVEC_PF:
 430         case VP56_MB_INTER_NOVEC_GF:
 431             for (b=0; b<b_max; b++) {
 432                 plane = vp56_b2p[b+ab];
 433                 off = s->block_offset[b];
 434                 s->dsp.put_pixels_tab[1][0](frame_current->data[plane] + off,
 435                                             frame_ref->data[plane] + off,
 436                                             s->stride[plane], 8);
 437                 s->dsp.idct_add(frame_current->data[plane] + off,
 438                                 s->stride[plane], s->block_coeff[b]);
 439             }
 440             break;
 441
 442         case VP56_MB_INTER_DELTA_PF:
 443         case VP56_MB_INTER_V1_PF:
 444         case VP56_MB_INTER_V2_PF:
 445         case VP56_MB_INTER_DELTA_GF:
 446         case VP56_MB_INTER_4V:
 447         case VP56_MB_INTER_V1_GF:
 448         case VP56_MB_INTER_V2_GF:
 449             for (b=0; b<b_max; b++) {
 450                 int x_off = b==1 || b==3 ? 8 : 0;
 451                 int y_off = b==2 || b==3 ? 8 : 0;
 452                 plane = vp56_b2p[b+ab];
 453                 vp56_mc(s, b, plane, frame_ref->data[plane], s->stride[plane],
 454                         16*col+x_off, 16*row+y_off);
 455                 s->dsp.idct_add(frame_current->data[plane] + s->block_offset[b],
 456                                 s->stride[plane], s->block_coeff[b]);
 457             }
 458             break;
 459     }
 460 }
 461
 462 static int vp56_size_changed(AVCodecContext *avctx)
 463 {
 464     vp56_context_t *s = avctx->priv_data;
 465     int stride = s->framep[VP56_FRAME_CURRENT]->linesize[0];
 466     int i;
 467
 468     s->plane_width[0]  = s->plane_width[3]  = avctx->coded_width;
 469     s->plane_width[1]  = s->plane_width[2]  = avctx->coded_width/2;
 470     s->plane_height[0] = s->plane_height[3] = avctx->coded_height;
 471     s->plane_height[1] = s->plane_height[2] = avctx->coded_height/2;
 472
 473     for (i=0; i<4; i++)
 474         s->stride[i] = s->flip * s->framep[VP56_FRAME_CURRENT]->linesize[i];
 475
 476     s->mb_width  = (avctx->coded_width +15) / 16;
 477     s->mb_height = (avctx->coded_height+15) / 16;
 478
 479     if (s->mb_width > 1000 || s->mb_height > 1000) {
 480         av_log(avctx, AV_LOG_ERROR, "picture too big\n");
 481         return -1;
 482     }
 483
 484     s->above_blocks = av_realloc(s->above_blocks,
 485                                  (4*s->mb_width+6) * sizeof(*s->above_blocks));
 486     s->macroblocks = av_realloc(s->macroblocks,
 487                                 s->mb_width*s->mb_height*sizeof(*s->macroblocks));
 488     av_free(s->edge_emu_buffer_alloc);
 489     s->edge_emu_buffer_alloc = av_malloc(16*stride);
 490     s->edge_emu_buffer = s->edge_emu_buffer_alloc;
 491     if (s->flip < 0)
 492         s->edge_emu_buffer += 15 * stride;
 493
 494     return 0;
 495 }
 496
 497 int vp56_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
 498                       const uint8_t *buf, int buf_size)
 499 {
 500     vp56_context_t *s = avctx->priv_data;
 501     AVFrame *const p = s->framep[VP56_FRAME_CURRENT];
 502     int remaining_buf_size = buf_size;
 503     int is_alpha, alpha_offset;
 504
 505     if (s->has_alpha) {
 506         alpha_offset = bytestream_get_be24(&buf);
 507         remaining_buf_size -= 3;
 508     }
 509
 510     for (is_alpha=0; is_alpha < 1+s->has_alpha; is_alpha++) {
 511         int mb_row, mb_col, mb_row_flip, mb_offset = 0;
 512         int block, y, uv, stride_y, stride_uv;
 513         int golden_frame = 0;
 514         int res;
 515
 516         s->modelp = &s->models[is_alpha];
 517
 518         res = s->parse_header(s, buf, remaining_buf_size, &golden_frame);
 519         if (!res)
 520             return -1;
 521
 522         if (!is_alpha) {
 523             p->reference = 1;
 524             if (avctx->get_buffer(avctx, p) < 0) {
 525                 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 526                 return -1;
 527             }
 528
 529             if (res == 2)
 530                 if (vp56_size_changed(avctx)) {
 531                     avctx->release_buffer(avctx, p);
 532                     return -1;
 533                 }
 534         }
 535
 536         if (p->key_frame) {
 537             p->pict_type = FF_I_TYPE;
 538             s->default_models_init(s);
 539             for (block=0; block<s->mb_height*s->mb_width; block++)
 540                 s->macroblocks[block].type = VP56_MB_INTRA;
 541         } else {
 542             p->pict_type = FF_P_TYPE;
 543             vp56_parse_mb_type_models(s);
 544             s->parse_vector_models(s);
 545             s->mb_type = VP56_MB_INTER_NOVEC_PF;
 546         }
 547
 548         s->parse_coeff_models(s);
 549
 550         memset(s->prev_dc, 0, sizeof(s->prev_dc));
 551         s->prev_dc[1][VP56_FRAME_CURRENT] = 128;
 552         s->prev_dc[2][VP56_FRAME_CURRENT] = 128;
 553
 554         for (block=0; block < 4*s->mb_width+6; block++) {
 555             s->above_blocks[block].ref_frame = VP56_FRAME_NONE;
 556             s->above_blocks[block].dc_coeff = 0;
 557             s->above_blocks[block].not_null_dc = 0;
 558         }
 559         s->above_blocks[2*s->mb_width + 2].ref_frame = VP56_FRAME_CURRENT;
 560         s->above_blocks[3*s->mb_width + 4].ref_frame = VP56_FRAME_CURRENT;
 561
 562         stride_y  = p->linesize[0];
 563         stride_uv = p->linesize[1];
 564
 565         if (s->flip < 0)
 566             mb_offset = 7;
 567
 568         /* main macroblocks loop */
 569         for (mb_row=0; mb_row<s->mb_height; mb_row++) {
 570             if (s->flip < 0)
 571                 mb_row_flip = s->mb_height - mb_row - 1;
 572             else
 573                 mb_row_flip = mb_row;
 574
 575             for (block=0; block<4; block++) {
 576                 s->left_block[block].ref_frame = VP56_FRAME_NONE;
 577                 s->left_block[block].dc_coeff = 0;
 578                 s->left_block[block].not_null_dc = 0;
 579             }
 580             memset(s->coeff_ctx, 0, sizeof(s->coeff_ctx));
 581             memset(s->coeff_ctx_last, 24, sizeof(s->coeff_ctx_last));
 582
 583             s->above_block_idx[0] = 1;
 584             s->above_block_idx[1] = 2;
 585             s->above_block_idx[2] = 1;
 586             s->above_block_idx[3] = 2;
 587             s->above_block_idx[4] = 2*s->mb_width + 2 + 1;
 588             s->above_block_idx[5] = 3*s->mb_width + 4 + 1;
 589
 590             s->block_offset[s->frbi] = (mb_row_flip*16 + mb_offset) * stride_y;
 591             s->block_offset[s->srbi] = s->block_offset[s->frbi] + 8*stride_y;
 592             s->block_offset[1] = s->block_offset[0] + 8;
 593             s->block_offset[3] = s->block_offset[2] + 8;
 594             s->block_offset[4] = (mb_row_flip*8 + mb_offset) * stride_uv;
 595             s->block_offset[5] = s->block_offset[4];
 596
 597             for (mb_col=0; mb_col<s->mb_width; mb_col++) {
 598                 vp56_decode_mb(s, mb_row, mb_col, is_alpha);
 599
 600                 for (y=0; y<4; y++) {
 601                     s->above_block_idx[y] += 2;
 602                     s->block_offset[y] += 16;
 603                 }
 604
 605                 for (uv=4; uv<6; uv++) {
 606                     s->above_block_idx[uv] += 1;
 607                     s->block_offset[uv] += 8;
 608                 }
 609             }
 610         }
 611
 612         if (p->key_frame || golden_frame) {
 613             if (s->framep[VP56_FRAME_GOLDEN]->data[0] &&
 614                 s->framep[VP56_FRAME_GOLDEN] != s->framep[VP56_FRAME_GOLDEN2])
 615                 avctx->release_buffer(avctx, s->framep[VP56_FRAME_GOLDEN]);
 616             s->framep[VP56_FRAME_GOLDEN] = p;
 617         }
 618
 619         if (s->has_alpha) {
 620             FFSWAP(AVFrame *, s->framep[VP56_FRAME_GOLDEN],
 621                               s->framep[VP56_FRAME_GOLDEN2]);
 622             buf += alpha_offset;
 623             remaining_buf_size -= alpha_offset;
 624         }
 625     }
 626
 627     if (s->framep[VP56_FRAME_PREVIOUS] == s->framep[VP56_FRAME_GOLDEN] ||
 628         s->framep[VP56_FRAME_PREVIOUS] == s->framep[VP56_FRAME_GOLDEN2]) {
 629         if (s->framep[VP56_FRAME_UNUSED] != s->framep[VP56_FRAME_GOLDEN] &&
 630             s->framep[VP56_FRAME_UNUSED] != s->framep[VP56_FRAME_GOLDEN2])
 631             FFSWAP(AVFrame *, s->framep[VP56_FRAME_PREVIOUS],
 632                               s->framep[VP56_FRAME_UNUSED]);
 633         else
 634             FFSWAP(AVFrame *, s->framep[VP56_FRAME_PREVIOUS],
 635                               s->framep[VP56_FRAME_UNUSED2]);
 636     } else if (s->framep[VP56_FRAME_PREVIOUS]->data[0])
 637         avctx->release_buffer(avctx, s->framep[VP56_FRAME_PREVIOUS]);
 638     FFSWAP(AVFrame *, s->framep[VP56_FRAME_CURRENT],
 639                       s->framep[VP56_FRAME_PREVIOUS]);
 640
 641     *(AVFrame*)data = *p;
 642     *data_size = sizeof(AVFrame);
 643
 644     return buf_size;
 645 }
 646
 647 av_cold void vp56_init(AVCodecContext *avctx, int flip, int has_alpha)
 648 {
 649     vp56_context_t *s = avctx->priv_data;
 650     int i;
 651
 652     s->avctx = avctx;
 653     avctx->pix_fmt = has_alpha ? PIX_FMT_YUVA420P : PIX_FMT_YUV420P;
 654
 655     if (avctx->idct_algo == FF_IDCT_AUTO)
 656         avctx->idct_algo = FF_IDCT_VP3;
 657     dsputil_init(&s->dsp, avctx);
 658     ff_init_scantable(s->dsp.idct_permutation, &s->scantable,ff_zigzag_direct);
 659
 660     avcodec_set_dimensions(avctx, 0, 0);
 661
 662     for (i=0; i<4; i++)
 663         s->framep[i] = &s->frames[i];
 664     s->framep[VP56_FRAME_UNUSED] = s->framep[VP56_FRAME_GOLDEN];
 665     s->framep[VP56_FRAME_UNUSED2] = s->framep[VP56_FRAME_GOLDEN2];
 666     s->edge_emu_buffer_alloc = NULL;
 667
 668     s->above_blocks = NULL;
 669     s->macroblocks = NULL;
 670     s->quantizer = -1;
 671     s->deblock_filtering = 1;
 672
 673     s->filter = NULL;
 674
 675     s->has_alpha = has_alpha;
 676     if (flip) {
 677         s->flip = -1;
 678         s->frbi = 2;
 679         s->srbi = 0;
 680     } else {
 681         s->flip = 1;
 682         s->frbi = 0;
 683         s->srbi = 2;
 684     }
 685 }
 686
 687 av_cold int vp56_free(AVCodecContext *avctx)
 688 {
 689     vp56_context_t *s = avctx->priv_data;
 690
 691     av_free(s->above_blocks);
 692     av_free(s->macroblocks);
 693     av_free(s->edge_emu_buffer_alloc);
 694     if (s->framep[VP56_FRAME_GOLDEN]->data[0])
 695         avctx->release_buffer(avctx, s->framep[VP56_FRAME_GOLDEN]);
 696     if (s->framep[VP56_FRAME_GOLDEN2]->data[0])
 697         avctx->release_buffer(avctx, s->framep[VP56_FRAME_GOLDEN2]);
 698     if (s->framep[VP56_FRAME_PREVIOUS]->data[0])
 699         avctx->release_buffer(avctx, s->framep[VP56_FRAME_PREVIOUS]);
 700     return 0;
 701 }