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

   1 /*
   2  * Copyright (C) 2004 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "libavutil/intmath.h"
  22 #include "libavutil/log.h"
  23 #include "libavutil/opt.h"
  24 #include "avcodec.h"
  25 #include "dsputil.h"
  26 #include "dwt.h"
  27 #include "internal.h"
  28 #include "snow.h"
  29
  30 #include "rangecoder.h"
  31 #include "mathops.h"
  32
  33 #include "mpegvideo.h"
  34 #include "h263.h"
  35
  36 #undef NDEBUG
  37 #include <assert.h>
  38
  39 static av_always_inline void predict_slice_buffered(SnowContext *s, slice_buffer * sb, IDWTELEM * old_buffer, int plane_index, int add, int mb_y){
  40     Plane *p= &s->plane[plane_index];
  41     const int mb_w= s->b_width  << s->block_max_depth;
  42     const int mb_h= s->b_height << s->block_max_depth;
  43     int x, y, mb_x;
  44     int block_size = MB_SIZE >> s->block_max_depth;
  45     int block_w    = plane_index ? block_size>>s->chroma_h_shift : block_size;
  46     int block_h    = plane_index ? block_size>>s->chroma_v_shift : block_size;
  47     const uint8_t *obmc  = plane_index ? ff_obmc_tab[s->block_max_depth+s->chroma_h_shift] : ff_obmc_tab[s->block_max_depth];
  48     int obmc_stride= plane_index ? (2*block_size)>>s->chroma_h_shift : 2*block_size;
  49     int ref_stride= s->current_picture.linesize[plane_index];
  50     uint8_t *dst8= s->current_picture.data[plane_index];
  51     int w= p->width;
  52     int h= p->height;
  53
  54     if(s->keyframe || (s->avctx->debug&512)){
  55         if(mb_y==mb_h)
  56             return;
  57
  58         if(add){
  59             for(y=block_h*mb_y; y<FFMIN(h,block_h*(mb_y+1)); y++){
  60 //                DWTELEM * line = slice_buffer_get_line(sb, y);
  61                 IDWTELEM * line = sb->line[y];
  62                 for(x=0; x<w; x++){
  63 //                    int v= buf[x + y*w] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
  64                     int v= line[x] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
  65                     v >>= FRAC_BITS;
  66                     if(v&(~255)) v= ~(v>>31);
  67                     dst8[x + y*ref_stride]= v;
  68                 }
  69             }
  70         }else{
  71             for(y=block_h*mb_y; y<FFMIN(h,block_h*(mb_y+1)); y++){
  72 //                DWTELEM * line = slice_buffer_get_line(sb, y);
  73                 IDWTELEM * line = sb->line[y];
  74                 for(x=0; x<w; x++){
  75                     line[x] -= 128 << FRAC_BITS;
  76 //                    buf[x + y*w]-= 128<<FRAC_BITS;
  77                 }
  78             }
  79         }
  80
  81         return;
  82     }
  83
  84     for(mb_x=0; mb_x<=mb_w; mb_x++){
  85         add_yblock(s, 1, sb, old_buffer, dst8, obmc,
  86                    block_w*mb_x - block_w/2,
  87                    block_h*mb_y - block_h/2,
  88                    block_w, block_h,
  89                    w, h,
  90                    w, ref_stride, obmc_stride,
  91                    mb_x - 1, mb_y - 1,
  92                    add, 0, plane_index);
  93     }
  94 }
  95
  96 static inline void decode_subband_slice_buffered(SnowContext *s, SubBand *b, slice_buffer * sb, int start_y, int h, int save_state[1]){
  97     const int w= b->width;
  98     int y;
  99     const int qlog= av_clip(s->qlog + b->qlog, 0, QROOT*16);
 100     int qmul= ff_qexp[qlog&(QROOT-1)]<<(qlog>>QSHIFT);
 101     int qadd= (s->qbias*qmul)>>QBIAS_SHIFT;
 102     int new_index = 0;
 103
 104     if(b->ibuf == s->spatial_idwt_buffer || s->qlog == LOSSLESS_QLOG){
 105         qadd= 0;
 106         qmul= 1<<QEXPSHIFT;
 107     }
 108
 109     /* If we are on the second or later slice, restore our index. */
 110     if (start_y != 0)
 111         new_index = save_state[0];
 112
 113
 114     for(y=start_y; y<h; y++){
 115         int x = 0;
 116         int v;
 117         IDWTELEM * line = slice_buffer_get_line(sb, y * b->stride_line + b->buf_y_offset) + b->buf_x_offset;
 118         memset(line, 0, b->width*sizeof(IDWTELEM));
 119         v = b->x_coeff[new_index].coeff;
 120         x = b->x_coeff[new_index++].x;
 121         while(x < w){
 122             register int t= ( (v>>1)*qmul + qadd)>>QEXPSHIFT;
 123             register int u= -(v&1);
 124             line[x] = (t^u) - u;
 125
 126             v = b->x_coeff[new_index].coeff;
 127             x = b->x_coeff[new_index++].x;
 128         }
 129     }
 130
 131     /* Save our variables for the next slice. */
 132     save_state[0] = new_index;
 133
 134     return;
 135 }
 136
 137 static int decode_q_branch(SnowContext *s, int level, int x, int y){
 138     const int w= s->b_width << s->block_max_depth;
 139     const int rem_depth= s->block_max_depth - level;
 140     const int index= (x + y*w) << rem_depth;
 141     int trx= (x+1)<<rem_depth;
 142     const BlockNode *left  = x ? &s->block[index-1] : &null_block;
 143     const BlockNode *top   = y ? &s->block[index-w] : &null_block;
 144     const BlockNode *tl    = y && x ? &s->block[index-w-1] : left;
 145     const BlockNode *tr    = y && trx<w && ((x&1)==0 || level==0) ? &s->block[index-w+(1<<rem_depth)] : tl; //FIXME use lt
 146     int s_context= 2*left->level + 2*top->level + tl->level + tr->level;
 147     int res;
 148
 149     if(s->keyframe){
 150         set_blocks(s, level, x, y, null_block.color[0], null_block.color[1], null_block.color[2], null_block.mx, null_block.my, null_block.ref, BLOCK_INTRA);
 151         return 0;
 152     }
 153
 154     if(level==s->block_max_depth || get_rac(&s->c, &s->block_state[4 + s_context])){
 155         int type, mx, my;
 156         int l = left->color[0];
 157         int cb= left->color[1];
 158         int cr= left->color[2];
 159         int ref = 0;
 160         int ref_context= av_log2(2*left->ref) + av_log2(2*top->ref);
 161         int mx_context= av_log2(2*FFABS(left->mx - top->mx)) + 0*av_log2(2*FFABS(tr->mx - top->mx));
 162         int my_context= av_log2(2*FFABS(left->my - top->my)) + 0*av_log2(2*FFABS(tr->my - top->my));
 163
 164         type= get_rac(&s->c, &s->block_state[1 + left->type + top->type]) ? BLOCK_INTRA : 0;
 165
 166         if(type){
 167             pred_mv(s, &mx, &my, 0, left, top, tr);
 168             l += get_symbol(&s->c, &s->block_state[32], 1);
 169             cb+= get_symbol(&s->c, &s->block_state[64], 1);
 170             cr+= get_symbol(&s->c, &s->block_state[96], 1);
 171         }else{
 172             if(s->ref_frames > 1)
 173                 ref= get_symbol(&s->c, &s->block_state[128 + 1024 + 32*ref_context], 0);
 174             if (ref >= s->ref_frames) {
 175                 av_log(s->avctx, AV_LOG_ERROR, "Invalid ref\n");
 176                 return AVERROR_INVALIDDATA;
 177             }
 178             pred_mv(s, &mx, &my, ref, left, top, tr);
 179             mx+= get_symbol(&s->c, &s->block_state[128 + 32*(mx_context + 16*!!ref)], 1);
 180             my+= get_symbol(&s->c, &s->block_state[128 + 32*(my_context + 16*!!ref)], 1);
 181         }
 182         set_blocks(s, level, x, y, l, cb, cr, mx, my, ref, type);
 183     }else{
 184         if ((res = decode_q_branch(s, level+1, 2*x+0, 2*y+0)) < 0 ||
 185             (res = decode_q_branch(s, level+1, 2*x+1, 2*y+0)) < 0 ||
 186             (res = decode_q_branch(s, level+1, 2*x+0, 2*y+1)) < 0 ||
 187             (res = decode_q_branch(s, level+1, 2*x+1, 2*y+1)) < 0)
 188             return res;
 189     }
 190     return 0;
 191 }
 192
 193 static void dequantize_slice_buffered(SnowContext *s, slice_buffer * sb, SubBand *b, IDWTELEM *src, int stride, int start_y, int end_y){
 194     const int w= b->width;
 195     const int qlog= av_clip(s->qlog + b->qlog, 0, QROOT*16);
 196     const int qmul= ff_qexp[qlog&(QROOT-1)]<<(qlog>>QSHIFT);
 197     const int qadd= (s->qbias*qmul)>>QBIAS_SHIFT;
 198     int x,y;
 199
 200     if(s->qlog == LOSSLESS_QLOG) return;
 201
 202     for(y=start_y; y<end_y; y++){
 203 //        DWTELEM * line = slice_buffer_get_line_from_address(sb, src + (y * stride));
 204         IDWTELEM * line = slice_buffer_get_line(sb, (y * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
 205         for(x=0; x<w; x++){
 206             int i= line[x];
 207             if(i<0){
 208                 line[x]= -((-i*qmul + qadd)>>(QEXPSHIFT)); //FIXME try different bias
 209             }else if(i>0){
 210                 line[x]=  (( i*qmul + qadd)>>(QEXPSHIFT));
 211             }
 212         }
 213     }
 214 }
 215
 216 static void correlate_slice_buffered(SnowContext *s, slice_buffer * sb, SubBand *b, IDWTELEM *src, int stride, int inverse, int use_median, int start_y, int end_y){
 217     const int w= b->width;
 218     int x,y;
 219
 220     IDWTELEM * line=0; // silence silly "could be used without having been initialized" warning
 221     IDWTELEM * prev;
 222
 223     if (start_y != 0)
 224         line = slice_buffer_get_line(sb, ((start_y - 1) * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
 225
 226     for(y=start_y; y<end_y; y++){
 227         prev = line;
 228 //        line = slice_buffer_get_line_from_address(sb, src + (y * stride));
 229         line = slice_buffer_get_line(sb, (y * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
 230         for(x=0; x<w; x++){
 231             if(x){
 232                 if(use_median){
 233                     if(y && x+1<w) line[x] += mid_pred(line[x - 1], prev[x], prev[x + 1]);
 234                     else  line[x] += line[x - 1];
 235                 }else{
 236                     if(y) line[x] += mid_pred(line[x - 1], prev[x], line[x - 1] + prev[x] - prev[x - 1]);
 237                     else  line[x] += line[x - 1];
 238                 }
 239             }else{
 240                 if(y) line[x] += prev[x];
 241             }
 242         }
 243     }
 244 }
 245
 246 static void decode_qlogs(SnowContext *s){
 247     int plane_index, level, orientation;
 248
 249     for(plane_index=0; plane_index<3; plane_index++){
 250         for(level=0; level<s->spatial_decomposition_count; level++){
 251             for(orientation=level ? 1:0; orientation<4; orientation++){
 252                 int q;
 253                 if     (plane_index==2) q= s->plane[1].band[level][orientation].qlog;
 254                 else if(orientation==2) q= s->plane[plane_index].band[level][1].qlog;
 255                 else                    q= get_symbol(&s->c, s->header_state, 1);
 256                 s->plane[plane_index].band[level][orientation].qlog= q;
 257             }
 258         }
 259     }
 260 }
 261
 262 #define GET_S(dst, check) \
 263     tmp= get_symbol(&s->c, s->header_state, 0);\
 264     if(!(check)){\
 265         av_log(s->avctx, AV_LOG_ERROR, "Error " #dst " is %d\n", tmp);\
 266         return -1;\
 267     }\
 268     dst= tmp;
 269
 270 static int decode_header(SnowContext *s){
 271     int plane_index, tmp;
 272     uint8_t kstate[32];
 273
 274     memset(kstate, MID_STATE, sizeof(kstate));
 275
 276     s->keyframe= get_rac(&s->c, kstate);
 277     if(s->keyframe || s->always_reset){
 278         ff_snow_reset_contexts(s);
 279         s->spatial_decomposition_type=
 280         s->qlog=
 281         s->qbias=
 282         s->mv_scale=
 283         s->block_max_depth= 0;
 284     }
 285     if(s->keyframe){
 286         GET_S(s->version, tmp <= 0U)
 287         s->always_reset= get_rac(&s->c, s->header_state);
 288         s->temporal_decomposition_type= get_symbol(&s->c, s->header_state, 0);
 289         s->temporal_decomposition_count= get_symbol(&s->c, s->header_state, 0);
 290         GET_S(s->spatial_decomposition_count, 0 < tmp && tmp <= MAX_DECOMPOSITIONS)
 291         s->colorspace_type= get_symbol(&s->c, s->header_state, 0);
 292         s->chroma_h_shift= get_symbol(&s->c, s->header_state, 0);
 293         s->chroma_v_shift= get_symbol(&s->c, s->header_state, 0);
 294
 295         if(s->chroma_h_shift == 1 && s->chroma_v_shift==1){
 296             s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
 297         }else if(s->chroma_h_shift == 0 && s->chroma_v_shift==0){
 298             s->avctx->pix_fmt= AV_PIX_FMT_YUV444P;
 299         }else if(s->chroma_h_shift == 2 && s->chroma_v_shift==2){
 300             s->avctx->pix_fmt= AV_PIX_FMT_YUV410P;
 301         } else {
 302             av_log(s, AV_LOG_ERROR, "unsupported color subsample mode %d %d\n", s->chroma_h_shift, s->chroma_v_shift);
 303             s->chroma_h_shift = s->chroma_v_shift = 1;
 304             s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
 305             return AVERROR_INVALIDDATA;
 306         }
 307
 308         s->spatial_scalability= get_rac(&s->c, s->header_state);
 309 //        s->rate_scalability= get_rac(&s->c, s->header_state);
 310         GET_S(s->max_ref_frames, tmp < (unsigned)MAX_REF_FRAMES)
 311         s->max_ref_frames++;
 312
 313         decode_qlogs(s);
 314     }
 315
 316     if(!s->keyframe){
 317         if(get_rac(&s->c, s->header_state)){
 318             for(plane_index=0; plane_index<2; plane_index++){
 319                 int htaps, i, sum=0;
 320                 Plane *p= &s->plane[plane_index];
 321                 p->diag_mc= get_rac(&s->c, s->header_state);
 322                 htaps= get_symbol(&s->c, s->header_state, 0)*2 + 2;
 323                 if((unsigned)htaps > HTAPS_MAX || htaps==0)
 324                     return -1;
 325                 p->htaps= htaps;
 326                 for(i= htaps/2; i; i--){
 327                     p->hcoeff[i]= get_symbol(&s->c, s->header_state, 0) * (1-2*(i&1));
 328                     sum += p->hcoeff[i];
 329                 }
 330                 p->hcoeff[0]= 32-sum;
 331             }
 332             s->plane[2].diag_mc= s->plane[1].diag_mc;
 333             s->plane[2].htaps  = s->plane[1].htaps;
 334             memcpy(s->plane[2].hcoeff, s->plane[1].hcoeff, sizeof(s->plane[1].hcoeff));
 335         }
 336         if(get_rac(&s->c, s->header_state)){
 337             GET_S(s->spatial_decomposition_count, 0 < tmp && tmp <= MAX_DECOMPOSITIONS)
 338             decode_qlogs(s);
 339         }
 340     }
 341
 342     s->spatial_decomposition_type+= get_symbol(&s->c, s->header_state, 1);
 343     if(s->spatial_decomposition_type > 1U){
 344         av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_type %d not supported\n", s->spatial_decomposition_type);
 345         return -1;
 346     }
 347     if(FFMIN(s->avctx-> width>>s->chroma_h_shift,
 348              s->avctx->height>>s->chroma_v_shift) >> (s->spatial_decomposition_count-1) <= 0){
 349         av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_count %d too large for size\n", s->spatial_decomposition_count);
 350         return -1;
 351     }
 352
 353
 354     s->qlog           += get_symbol(&s->c, s->header_state, 1);
 355     s->mv_scale       += get_symbol(&s->c, s->header_state, 1);
 356     s->qbias          += get_symbol(&s->c, s->header_state, 1);
 357     s->block_max_depth+= get_symbol(&s->c, s->header_state, 1);
 358     if(s->block_max_depth > 1 || s->block_max_depth < 0){
 359         av_log(s->avctx, AV_LOG_ERROR, "block_max_depth= %d is too large\n", s->block_max_depth);
 360         s->block_max_depth= 0;
 361         return -1;
 362     }
 363
 364     return 0;
 365 }
 366
 367 static av_cold int decode_init(AVCodecContext *avctx)
 368 {
 369     int ret;
 370
 371     if ((ret = ff_snow_common_init(avctx)) < 0) {
 372         ff_snow_common_end(avctx->priv_data);
 373         return ret;
 374     }
 375
 376     return 0;
 377 }
 378
 379 static int decode_blocks(SnowContext *s){
 380     int x, y;
 381     int w= s->b_width;
 382     int h= s->b_height;
 383     int res;
 384
 385     for(y=0; y<h; y++){
 386         for(x=0; x<w; x++){
 387             if ((res = decode_q_branch(s, 0, x, y)) < 0)
 388                 return res;
 389         }
 390     }
 391     return 0;
 392 }
 393
 394 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt){
 395     const uint8_t *buf = avpkt->data;
 396     int buf_size = avpkt->size;
 397     SnowContext *s = avctx->priv_data;
 398     RangeCoder * const c= &s->c;
 399     int bytes_read;
 400     AVFrame *picture = data;
 401     int level, orientation, plane_index;
 402     int res;
 403
 404     ff_init_range_decoder(c, buf, buf_size);
 405     ff_build_rac_states(c, 0.05*(1LL<<32), 256-8);
 406
 407     s->current_picture.pict_type= AV_PICTURE_TYPE_I; //FIXME I vs. P
 408     if(decode_header(s)<0)
 409         return -1;
 410     if ((res=ff_snow_common_init_after_header(avctx)) < 0)
 411         return res;
 412
 413     // realloc slice buffer for the case that spatial_decomposition_count changed
 414     ff_slice_buffer_destroy(&s->sb);
 415     if ((res = ff_slice_buffer_init(&s->sb, s->plane[0].height,
 416                                     (MB_SIZE >> s->block_max_depth) +
 417                                     s->spatial_decomposition_count * 11 + 1,
 418                                     s->plane[0].width,
 419                                     s->spatial_idwt_buffer)) < 0)
 420         return res;
 421
 422     for(plane_index=0; plane_index<3; plane_index++){
 423         Plane *p= &s->plane[plane_index];
 424         p->fast_mc= p->diag_mc && p->htaps==6 && p->hcoeff[0]==40
 425                                               && p->hcoeff[1]==-10
 426                                               && p->hcoeff[2]==2;
 427     }
 428
 429     ff_snow_alloc_blocks(s);
 430
 431     if(ff_snow_frame_start(s) < 0)
 432         return -1;
 433     //keyframe flag duplication mess FIXME
 434     if(avctx->debug&FF_DEBUG_PICT_INFO)
 435         av_log(avctx, AV_LOG_ERROR, "keyframe:%d qlog:%d\n", s->keyframe, s->qlog);
 436
 437     if ((res = decode_blocks(s)) < 0)
 438         return res;
 439
 440     for(plane_index=0; plane_index<3; plane_index++){
 441         Plane *p= &s->plane[plane_index];
 442         int w= p->width;
 443         int h= p->height;
 444         int x, y;
 445         int decode_state[MAX_DECOMPOSITIONS][4][1]; /* Stored state info for unpack_coeffs. 1 variable per instance. */
 446
 447         if(s->avctx->debug&2048){
 448             memset(s->spatial_dwt_buffer, 0, sizeof(DWTELEM)*w*h);
 449             predict_plane(s, s->spatial_idwt_buffer, plane_index, 1);
 450
 451             for(y=0; y<h; y++){
 452                 for(x=0; x<w; x++){
 453                     int v= s->current_picture.data[plane_index][y*s->current_picture.linesize[plane_index] + x];
 454                     s->mconly_picture.data[plane_index][y*s->mconly_picture.linesize[plane_index] + x]= v;
 455                 }
 456             }
 457         }
 458
 459         {
 460         for(level=0; level<s->spatial_decomposition_count; level++){
 461             for(orientation=level ? 1 : 0; orientation<4; orientation++){
 462                 SubBand *b= &p->band[level][orientation];
 463                 unpack_coeffs(s, b, b->parent, orientation);
 464             }
 465         }
 466         }
 467
 468         {
 469         const int mb_h= s->b_height << s->block_max_depth;
 470         const int block_size = MB_SIZE >> s->block_max_depth;
 471         const int block_h    = plane_index ? block_size>>s->chroma_v_shift : block_size;
 472         int mb_y;
 473         DWTCompose cs[MAX_DECOMPOSITIONS];
 474         int yd=0, yq=0;
 475         int y;
 476         int end_y;
 477
 478         ff_spatial_idwt_buffered_init(cs, &s->sb, w, h, 1, s->spatial_decomposition_type, s->spatial_decomposition_count);
 479         for(mb_y=0; mb_y<=mb_h; mb_y++){
 480
 481             int slice_starty = block_h*mb_y;
 482             int slice_h = block_h*(mb_y+1);
 483
 484             if (!(s->keyframe || s->avctx->debug&512)){
 485                 slice_starty = FFMAX(0, slice_starty - (block_h >> 1));
 486                 slice_h -= (block_h >> 1);
 487             }
 488
 489             for(level=0; level<s->spatial_decomposition_count; level++){
 490                 for(orientation=level ? 1 : 0; orientation<4; orientation++){
 491                     SubBand *b= &p->band[level][orientation];
 492                     int start_y;
 493                     int end_y;
 494                     int our_mb_start = mb_y;
 495                     int our_mb_end = (mb_y + 1);
 496                     const int extra= 3;
 497                     start_y = (mb_y ? ((block_h * our_mb_start) >> (s->spatial_decomposition_count - level)) + s->spatial_decomposition_count - level + extra: 0);
 498                     end_y = (((block_h * our_mb_end) >> (s->spatial_decomposition_count - level)) + s->spatial_decomposition_count - level + extra);
 499                     if (!(s->keyframe || s->avctx->debug&512)){
 500                         start_y = FFMAX(0, start_y - (block_h >> (1+s->spatial_decomposition_count - level)));
 501                         end_y = FFMAX(0, end_y - (block_h >> (1+s->spatial_decomposition_count - level)));
 502                     }
 503                     start_y = FFMIN(b->height, start_y);
 504                     end_y = FFMIN(b->height, end_y);
 505
 506                     if (start_y != end_y){
 507                         if (orientation == 0){
 508                             SubBand * correlate_band = &p->band[0][0];
 509                             int correlate_end_y = FFMIN(b->height, end_y + 1);
 510                             int correlate_start_y = FFMIN(b->height, (start_y ? start_y + 1 : 0));
 511                             decode_subband_slice_buffered(s, correlate_band, &s->sb, correlate_start_y, correlate_end_y, decode_state[0][0]);
 512                             correlate_slice_buffered(s, &s->sb, correlate_band, correlate_band->ibuf, correlate_band->stride, 1, 0, correlate_start_y, correlate_end_y);
 513                             dequantize_slice_buffered(s, &s->sb, correlate_band, correlate_band->ibuf, correlate_band->stride, start_y, end_y);
 514                         }
 515                         else
 516                             decode_subband_slice_buffered(s, b, &s->sb, start_y, end_y, decode_state[level][orientation]);
 517                     }
 518                 }
 519             }
 520
 521             for(; yd<slice_h; yd+=4){
 522                 ff_spatial_idwt_buffered_slice(&s->dwt, cs, &s->sb, s->temp_idwt_buffer, w, h, 1, s->spatial_decomposition_type, s->spatial_decomposition_count, yd);
 523             }
 524
 525             if(s->qlog == LOSSLESS_QLOG){
 526                 for(; yq<slice_h && yq<h; yq++){
 527                     IDWTELEM * line = slice_buffer_get_line(&s->sb, yq);
 528                     for(x=0; x<w; x++){
 529                         line[x] <<= FRAC_BITS;
 530                     }
 531                 }
 532             }
 533
 534             predict_slice_buffered(s, &s->sb, s->spatial_idwt_buffer, plane_index, 1, mb_y);
 535
 536             y = FFMIN(p->height, slice_starty);
 537             end_y = FFMIN(p->height, slice_h);
 538             while(y < end_y)
 539                 ff_slice_buffer_release(&s->sb, y++);
 540         }
 541
 542         ff_slice_buffer_flush(&s->sb);
 543         }
 544
 545     }
 546
 547     emms_c();
 548
 549     ff_snow_release_buffer(avctx);
 550
 551     if(!(s->avctx->debug&2048))
 552         *picture= s->current_picture;
 553     else
 554         *picture= s->mconly_picture;
 555
 556     *data_size = sizeof(AVFrame);
 557
 558     bytes_read= c->bytestream - c->bytestream_start;
 559     if(bytes_read ==0) av_log(s->avctx, AV_LOG_ERROR, "error at end of frame\n"); //FIXME
 560
 561     return bytes_read;
 562 }
 563
 564 static av_cold int decode_end(AVCodecContext *avctx)
 565 {
 566     SnowContext *s = avctx->priv_data;
 567
 568     ff_slice_buffer_destroy(&s->sb);
 569
 570     ff_snow_common_end(s);
 571
 572     return 0;
 573 }
 574
 575 AVCodec ff_snow_decoder = {
 576     .name           = "snow",
 577     .type           = AVMEDIA_TYPE_VIDEO,
 578     .id             = AV_CODEC_ID_SNOW,
 579     .priv_data_size = sizeof(SnowContext),
 580     .init           = decode_init,
 581     .close          = decode_end,
 582     .decode         = decode_frame,
 583     .capabilities   = CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
 584     .long_name      = NULL_IF_CONFIG_SMALL("Snow"),
 585 };