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