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/emms.h"
  22 #include "libavutil/intmath.h"
  23 #include "libavutil/log.h"
  24 #include "libavutil/mem.h"
  25 #include "avcodec.h"
  26 #include "codec_internal.h"
  27 #include "decode.h"
  28 #include "snow_dwt.h"
  29 #include "snow.h"
  30
  31 #include "rangecoder.h"
  32 #include "mathops.h"
  33
  34 static inline int get_symbol(RangeCoder *c, uint8_t *state, int is_signed)
  35 {
  36     if (get_rac(c, state + 0))
  37         return 0;
  38     else {
  39         int e;
  40         unsigned a;
  41         e = 0;
  42         while (get_rac(c, state + 1 + FFMIN(e, 9))) { //1..10
  43             e++;
  44             if (e > 31)
  45                 return AVERROR_INVALIDDATA;
  46         }
  47
  48         a = 1;
  49         for (int i = e - 1; i >= 0; i--)
  50             a += a + get_rac(c, state + 22 + FFMIN(i, 9)); //22..31
  51
  52         e = -(is_signed && get_rac(c, state + 11 + FFMIN(e, 10))); //11..21
  53         return (a ^ e) - e;
  54     }
  55 }
  56
  57 static inline int get_symbol2(RangeCoder *c, uint8_t *state, int log2)
  58 {
  59     int r = log2 >= 0 ? 1 << log2 : 1;
  60     int v = 0;
  61
  62     av_assert2(log2 >= -4);
  63
  64     while (log2 < 28 && get_rac(c, state + 4 + log2)) {
  65         v += r;
  66         log2++;
  67         if (log2 > 0) r += r;
  68     }
  69
  70     for (int i = log2 - 1; i >= 0; i--)
  71         v += get_rac(c, state + 31 - i) << i;
  72
  73     return v;
  74 }
  75
  76 static void unpack_coeffs(SnowContext *s, SubBand *b, SubBand * parent, int orientation)
  77 {
  78     const int w = b->width;
  79     const int h = b->height;
  80
  81     int run, runs;
  82     x_and_coeff *xc = b->x_coeff;
  83     x_and_coeff *prev_xc = NULL;
  84     x_and_coeff *prev2_xc = xc;
  85     x_and_coeff *parent_xc = parent ? parent->x_coeff : NULL;
  86     x_and_coeff *prev_parent_xc = parent_xc;
  87
  88     runs = get_symbol2(&s->c, b->state[30], 0);
  89     if (runs-- > 0) run = get_symbol2(&s->c, b->state[1], 3);
  90     else            run = INT_MAX;
  91
  92     for (int y = 0; y < h; y++) {
  93         int v = 0;
  94         int lt = 0, t = 0, rt = 0;
  95
  96         if (y && prev_xc->x == 0)
  97             rt = prev_xc->coeff;
  98
  99         for (int x = 0; x < w; x++) {
 100             int p = 0;
 101             const int l = v;
 102
 103             lt= t; t= rt;
 104
 105             if (y) {
 106                 if (prev_xc->x <= x)
 107                     prev_xc++;
 108                 if (prev_xc->x == x + 1)
 109                     rt = prev_xc->coeff;
 110                 else
 111                     rt = 0;
 112             }
 113             if (parent_xc) {
 114                 if (x>>1 > parent_xc->x)
 115                     parent_xc++;
 116                 if (x>>1 == parent_xc->x)
 117                     p = parent_xc->coeff;
 118             }
 119             if (/*ll|*/l|lt|t|rt|p) {
 120                 int context = av_log2(/*FFABS(ll) + */3*(l>>1) + (lt>>1) + (t&~1) + (rt>>1) + (p>>1));
 121
 122                 v = get_rac(&s->c, &b->state[0][context]);
 123                 if (v) {
 124                     v  = 2*(get_symbol2(&s->c, b->state[context + 2], context-4) + 1);
 125                     v += get_rac(&s->c, &b->state[0][16 + 1 + 3 + ff_quant3bA[l&0xFF] + 3 * ff_quant3bA[t&0xFF]]);
 126                     if ((uint16_t)v != v) {
 127                         av_log(s->avctx, AV_LOG_ERROR, "Coefficient damaged\n");
 128                         v = 1;
 129                     }
 130                     xc->x = x;
 131                     (xc++)->coeff = v;
 132                 }
 133             } else {
 134                 if (!run) {
 135                     if (runs-- > 0) run = get_symbol2(&s->c, b->state[1], 3);
 136                     else            run = INT_MAX;
 137                     v  = 2 * (get_symbol2(&s->c, b->state[0 + 2], 0-4) + 1);
 138                     v += get_rac(&s->c, &b->state[0][16 + 1 + 3]);
 139                     if ((uint16_t)v != v) {
 140                         av_log(s->avctx, AV_LOG_ERROR, "Coefficient damaged\n");
 141                         v = 1;
 142                     }
 143
 144                     xc->x = x;
 145                     (xc++)->coeff = v;
 146                 } else {
 147                     int max_run;
 148                     run--;
 149                     v = 0;
 150                     av_assert2(run >= 0);
 151                     if (y) max_run = FFMIN(run, prev_xc->x - x - 2);
 152                     else   max_run = FFMIN(run, w-x-1);
 153                     if (parent_xc)
 154                         max_run = FFMIN(max_run, 2*parent_xc->x - x - 1);
 155                     av_assert2(max_run >= 0 && max_run <= run);
 156
 157                     x   += max_run;
 158                     run -= max_run;
 159                 }
 160             }
 161         }
 162         (xc++)->x = w+1; //end marker
 163         prev_xc  = prev2_xc;
 164         prev2_xc = xc;
 165
 166         if (parent_xc) {
 167             if (y & 1) {
 168                 while (parent_xc->x != parent->width+1)
 169                     parent_xc++;
 170                 parent_xc++;
 171                 prev_parent_xc= parent_xc;
 172             } else {
 173                 parent_xc= prev_parent_xc;
 174             }
 175         }
 176     }
 177
 178     (xc++)->x = w + 1; //end marker
 179 }
 180
 181 static av_always_inline void predict_slice_buffered(SnowContext *s, slice_buffer * sb, IDWTELEM * old_buffer, int plane_index, int add, int mb_y){
 182     Plane *p= &s->plane[plane_index];
 183     const int mb_w= s->b_width  << s->block_max_depth;
 184     const int mb_h= s->b_height << s->block_max_depth;
 185     int x, y, mb_x;
 186     int block_size = MB_SIZE >> s->block_max_depth;
 187     int block_w    = plane_index ? block_size>>s->chroma_h_shift : block_size;
 188     int block_h    = plane_index ? block_size>>s->chroma_v_shift : block_size;
 189     const uint8_t *obmc  = plane_index ? ff_obmc_tab[s->block_max_depth+s->chroma_h_shift] : ff_obmc_tab[s->block_max_depth];
 190     int obmc_stride= plane_index ? (2*block_size)>>s->chroma_h_shift : 2*block_size;
 191     int ref_stride= s->current_picture->linesize[plane_index];
 192     uint8_t *dst8= s->current_picture->data[plane_index];
 193     int w= p->width;
 194     int h= p->height;
 195
 196     if(s->keyframe || (s->avctx->debug&512)){
 197         if(mb_y==mb_h)
 198             return;
 199
 200         if(add){
 201             for(y=block_h*mb_y; y<FFMIN(h,block_h*(mb_y+1)); y++){
 202 //                DWTELEM * line = slice_buffer_get_line(sb, y);
 203                 IDWTELEM * line = sb->line[y];
 204                 for(x=0; x<w; x++){
 205 //                    int v= buf[x + y*w] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
 206                     int v= line[x] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
 207                     v >>= FRAC_BITS;
 208                     if(v&(~255)) v= ~(v>>31);
 209                     dst8[x + y*ref_stride]= v;
 210                 }
 211             }
 212         }else{
 213             for(y=block_h*mb_y; y<FFMIN(h,block_h*(mb_y+1)); y++){
 214 //                DWTELEM * line = slice_buffer_get_line(sb, y);
 215                 IDWTELEM * line = sb->line[y];
 216                 for(x=0; x<w; x++){
 217                     line[x] -= 128 << FRAC_BITS;
 218 //                    buf[x + y*w]-= 128<<FRAC_BITS;
 219                 }
 220             }
 221         }
 222
 223         return;
 224     }
 225
 226     for(mb_x=0; mb_x<=mb_w; mb_x++){
 227         add_yblock(s, 1, sb, old_buffer, dst8, obmc,
 228                    block_w*mb_x - block_w/2,
 229                    block_h*mb_y - block_h/2,
 230                    block_w, block_h,
 231                    w, h,
 232                    w, ref_stride, obmc_stride,
 233                    mb_x - 1, mb_y - 1,
 234                    add, 0, plane_index);
 235     }
 236
 237     if(s->avmv && mb_y < mb_h && plane_index == 0)
 238         for(mb_x=0; mb_x<mb_w; mb_x++){
 239             AVMotionVector *avmv = s->avmv + s->avmv_index;
 240             const int b_width = s->b_width  << s->block_max_depth;
 241             const int b_stride= b_width;
 242             BlockNode *bn= &s->block[mb_x + mb_y*b_stride];
 243
 244             if (bn->type)
 245                 continue;
 246
 247             s->avmv_index++;
 248
 249             avmv->w = block_w;
 250             avmv->h = block_h;
 251             avmv->dst_x = block_w*mb_x - block_w/2;
 252             avmv->dst_y = block_h*mb_y - block_h/2;
 253             avmv->motion_scale = 8;
 254             avmv->motion_x = bn->mx * s->mv_scale;
 255             avmv->motion_y = bn->my * s->mv_scale;
 256             avmv->src_x = avmv->dst_x + avmv->motion_x / 8;
 257             avmv->src_y = avmv->dst_y + avmv->motion_y / 8;
 258             avmv->source= -1 - bn->ref;
 259             avmv->flags = 0;
 260         }
 261 }
 262
 263 static inline void decode_subband_slice_buffered(SnowContext *s, SubBand *b, slice_buffer * sb, int start_y, int h, int save_state[1]){
 264     const int w= b->width;
 265     int y;
 266     const int qlog= av_clip(s->qlog + (int64_t)b->qlog, 0, QROOT*16);
 267     int qmul= ff_qexp[qlog&(QROOT-1)]<<(qlog>>QSHIFT);
 268     int qadd= (s->qbias*qmul)>>QBIAS_SHIFT;
 269     int new_index = 0;
 270
 271     if(b->ibuf == s->spatial_idwt_buffer || s->qlog == LOSSLESS_QLOG){
 272         qadd= 0;
 273         qmul= 1<<QEXPSHIFT;
 274     }
 275
 276     /* If we are on the second or later slice, restore our index. */
 277     if (start_y != 0)
 278         new_index = save_state[0];
 279
 280
 281     for(y=start_y; y<h; y++){
 282         int x = 0;
 283         int v;
 284         IDWTELEM * line = slice_buffer_get_line(sb, y * b->stride_line + b->buf_y_offset) + b->buf_x_offset;
 285         memset(line, 0, b->width*sizeof(IDWTELEM));
 286         v = b->x_coeff[new_index].coeff;
 287         x = b->x_coeff[new_index++].x;
 288         while(x < w){
 289             register int t= (int)( (v>>1)*(unsigned)qmul + qadd)>>QEXPSHIFT;
 290             register int u= -(v&1);
 291             line[x] = (t^u) - u;
 292
 293             v = b->x_coeff[new_index].coeff;
 294             x = b->x_coeff[new_index++].x;
 295         }
 296     }
 297
 298     /* Save our variables for the next slice. */
 299     save_state[0] = new_index;
 300
 301     return;
 302 }
 303
 304 static int decode_q_branch(SnowContext *s, int level, int x, int y){
 305     const int w= s->b_width << s->block_max_depth;
 306     const int rem_depth= s->block_max_depth - level;
 307     const int index= (x + y*w) << rem_depth;
 308     int trx= (x+1)<<rem_depth;
 309     const BlockNode *left  = x ? &s->block[index-1] : &null_block;
 310     const BlockNode *top   = y ? &s->block[index-w] : &null_block;
 311     const BlockNode *tl    = y && x ? &s->block[index-w-1] : left;
 312     const BlockNode *tr    = y && trx<w && ((x&1)==0 || level==0) ? &s->block[index-w+(1<<rem_depth)] : tl; //FIXME use lt
 313     int s_context= 2*left->level + 2*top->level + tl->level + tr->level;
 314     int res;
 315
 316     if(s->keyframe){
 317         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);
 318         return 0;
 319     }
 320
 321     if(level==s->block_max_depth || get_rac(&s->c, &s->block_state[4 + s_context])){
 322         int type, mx, my;
 323         int l = left->color[0];
 324         int cb= left->color[1];
 325         int cr= left->color[2];
 326         unsigned ref = 0;
 327         int ref_context= av_log2(2*left->ref) + av_log2(2*top->ref);
 328         int mx_context= av_log2(2*FFABS(left->mx - top->mx)) + 0*av_log2(2*FFABS(tr->mx - top->mx));
 329         int my_context= av_log2(2*FFABS(left->my - top->my)) + 0*av_log2(2*FFABS(tr->my - top->my));
 330
 331         type= get_rac(&s->c, &s->block_state[1 + left->type + top->type]) ? BLOCK_INTRA : 0;
 332         if(type){
 333             int ld, cbd, crd;
 334             pred_mv(s, &mx, &my, 0, left, top, tr);
 335             ld = get_symbol(&s->c, &s->block_state[32], 1);
 336             if (ld < -255 || ld > 255) {
 337                 return AVERROR_INVALIDDATA;
 338             }
 339             l += ld;
 340             if (s->nb_planes > 2) {
 341                 cbd = get_symbol(&s->c, &s->block_state[64], 1);
 342                 crd = get_symbol(&s->c, &s->block_state[96], 1);
 343                 if (cbd < -255 || cbd > 255 || crd < -255 || crd > 255) {
 344                     return AVERROR_INVALIDDATA;
 345                 }
 346                 cb += cbd;
 347                 cr += crd;
 348             }
 349         }else{
 350             if(s->ref_frames > 1)
 351                 ref= get_symbol(&s->c, &s->block_state[128 + 1024 + 32*ref_context], 0);
 352             if (ref >= s->ref_frames) {
 353                 av_log(s->avctx, AV_LOG_ERROR, "Invalid ref\n");
 354                 return AVERROR_INVALIDDATA;
 355             }
 356             pred_mv(s, &mx, &my, ref, left, top, tr);
 357             mx+= (unsigned)get_symbol(&s->c, &s->block_state[128 + 32*(mx_context + 16*!!ref)], 1);
 358             my+= (unsigned)get_symbol(&s->c, &s->block_state[128 + 32*(my_context + 16*!!ref)], 1);
 359         }
 360         set_blocks(s, level, x, y, l, cb, cr, mx, my, ref, type);
 361     }else{
 362         if ((res = decode_q_branch(s, level+1, 2*x+0, 2*y+0)) < 0 ||
 363             (res = decode_q_branch(s, level+1, 2*x+1, 2*y+0)) < 0 ||
 364             (res = decode_q_branch(s, level+1, 2*x+0, 2*y+1)) < 0 ||
 365             (res = decode_q_branch(s, level+1, 2*x+1, 2*y+1)) < 0)
 366             return res;
 367     }
 368     return 0;
 369 }
 370
 371 static void dequantize_slice_buffered(SnowContext *s, slice_buffer * sb, SubBand *b, IDWTELEM *src, int stride, int start_y, int end_y){
 372     const int w= b->width;
 373     const int qlog= av_clip(s->qlog + (int64_t)b->qlog, 0, QROOT*16);
 374     const int qmul= ff_qexp[qlog&(QROOT-1)]<<(qlog>>QSHIFT);
 375     const int qadd= (s->qbias*qmul)>>QBIAS_SHIFT;
 376     int x,y;
 377
 378     if(s->qlog == LOSSLESS_QLOG) return;
 379
 380     for(y=start_y; y<end_y; y++){
 381 //        DWTELEM * line = slice_buffer_get_line_from_address(sb, src + (y * stride));
 382         IDWTELEM * line = slice_buffer_get_line(sb, (y * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
 383         for(x=0; x<w; x++){
 384             int i= line[x];
 385             if(i<0){
 386                 line[x]= -((-i*(unsigned)qmul + qadd)>>(QEXPSHIFT)); //FIXME try different bias
 387             }else if(i>0){
 388                 line[x]=  (( i*(unsigned)qmul + qadd)>>(QEXPSHIFT));
 389             }
 390         }
 391     }
 392 }
 393
 394 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){
 395     const int w= b->width;
 396     int x,y;
 397
 398     IDWTELEM * line=0; // silence silly "could be used without having been initialized" warning
 399     IDWTELEM * prev;
 400
 401     if (start_y != 0)
 402         line = slice_buffer_get_line(sb, ((start_y - 1) * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
 403
 404     for(y=start_y; y<end_y; y++){
 405         prev = line;
 406 //        line = slice_buffer_get_line_from_address(sb, src + (y * stride));
 407         line = slice_buffer_get_line(sb, (y * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
 408         for(x=0; x<w; x++){
 409             if(x){
 410                 if(use_median){
 411                     if(y && x+1<w) line[x] += mid_pred(line[x - 1], prev[x], prev[x + 1]);
 412                     else  line[x] += line[x - 1];
 413                 }else{
 414                     if(y) line[x] += mid_pred(line[x - 1], prev[x], line[x - 1] + prev[x] - prev[x - 1]);
 415                     else  line[x] += line[x - 1];
 416                 }
 417             }else{
 418                 if(y) line[x] += prev[x];
 419             }
 420         }
 421     }
 422 }
 423
 424 static void decode_qlogs(SnowContext *s){
 425     int plane_index, level, orientation;
 426
 427     for(plane_index=0; plane_index < s->nb_planes; plane_index++){
 428         for(level=0; level<s->spatial_decomposition_count; level++){
 429             for(orientation=level ? 1:0; orientation<4; orientation++){
 430                 int q;
 431                 if     (plane_index==2) q= s->plane[1].band[level][orientation].qlog;
 432                 else if(orientation==2) q= s->plane[plane_index].band[level][1].qlog;
 433                 else                    q= get_symbol(&s->c, s->header_state, 1);
 434                 s->plane[plane_index].band[level][orientation].qlog= q;
 435             }
 436         }
 437     }
 438 }
 439
 440 #define GET_S(dst, check) \
 441     tmp= get_symbol(&s->c, s->header_state, 0);\
 442     if(!(check)){\
 443         av_log(s->avctx, AV_LOG_ERROR, "Error " #dst " is %d\n", tmp);\
 444         return AVERROR_INVALIDDATA;\
 445     }\
 446     dst= tmp;
 447
 448 static int decode_header(SnowContext *s){
 449     int plane_index, tmp;
 450     uint8_t kstate[32];
 451
 452     memset(kstate, MID_STATE, sizeof(kstate));
 453
 454     s->keyframe= get_rac(&s->c, kstate);
 455     if(s->keyframe || s->always_reset){
 456         ff_snow_reset_contexts(s);
 457         s->spatial_decomposition_type=
 458         s->qlog=
 459         s->qbias=
 460         s->mv_scale=
 461         s->block_max_depth= 0;
 462     }
 463     if(s->keyframe){
 464         GET_S(s->version, tmp <= 0U)
 465         s->always_reset= get_rac(&s->c, s->header_state);
 466         s->temporal_decomposition_type= get_symbol(&s->c, s->header_state, 0);
 467         s->temporal_decomposition_count= get_symbol(&s->c, s->header_state, 0);
 468         GET_S(s->spatial_decomposition_count, 0 < tmp && tmp <= MAX_DECOMPOSITIONS)
 469         s->colorspace_type= get_symbol(&s->c, s->header_state, 0);
 470         if (s->colorspace_type == 1) {
 471             s->avctx->pix_fmt= AV_PIX_FMT_GRAY8;
 472             s->nb_planes = 1;
 473         } else if(s->colorspace_type == 0) {
 474             s->chroma_h_shift= get_symbol(&s->c, s->header_state, 0);
 475             s->chroma_v_shift= get_symbol(&s->c, s->header_state, 0);
 476
 477             if(s->chroma_h_shift == 1 && s->chroma_v_shift==1){
 478                 s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
 479             }else if(s->chroma_h_shift == 0 && s->chroma_v_shift==0){
 480                 s->avctx->pix_fmt= AV_PIX_FMT_YUV444P;
 481             }else if(s->chroma_h_shift == 2 && s->chroma_v_shift==2){
 482                 s->avctx->pix_fmt= AV_PIX_FMT_YUV410P;
 483             } else {
 484                 av_log(s, AV_LOG_ERROR, "unsupported color subsample mode %d %d\n", s->chroma_h_shift, s->chroma_v_shift);
 485                 s->chroma_h_shift = s->chroma_v_shift = 1;
 486                 s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
 487                 return AVERROR_INVALIDDATA;
 488             }
 489             s->nb_planes = 3;
 490         } else {
 491             av_log(s, AV_LOG_ERROR, "unsupported color space\n");
 492             s->chroma_h_shift = s->chroma_v_shift = 1;
 493             s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
 494             return AVERROR_INVALIDDATA;
 495         }
 496
 497
 498         s->spatial_scalability= get_rac(&s->c, s->header_state);
 499 //        s->rate_scalability= get_rac(&s->c, s->header_state);
 500         GET_S(s->max_ref_frames, tmp < (unsigned)MAX_REF_FRAMES)
 501         s->max_ref_frames++;
 502
 503         decode_qlogs(s);
 504     }
 505
 506     if(!s->keyframe){
 507         if(get_rac(&s->c, s->header_state)){
 508             for(plane_index=0; plane_index<FFMIN(s->nb_planes, 2); plane_index++){
 509                 int htaps, i, sum=0;
 510                 Plane *p= &s->plane[plane_index];
 511                 p->diag_mc= get_rac(&s->c, s->header_state);
 512                 htaps= get_symbol(&s->c, s->header_state, 0);
 513                 if((unsigned)htaps >= HTAPS_MAX/2 - 1)
 514                     return AVERROR_INVALIDDATA;
 515                 htaps = htaps*2 + 2;
 516                 p->htaps= htaps;
 517                 for(i= htaps/2; i; i--){
 518                     unsigned hcoeff = get_symbol(&s->c, s->header_state, 0);
 519                     if (hcoeff > 127)
 520                         return AVERROR_INVALIDDATA;
 521                     p->hcoeff[i]= hcoeff * (1-2*(i&1));
 522                     sum += p->hcoeff[i];
 523                 }
 524                 p->hcoeff[0]= 32-sum;
 525             }
 526             s->plane[2].diag_mc= s->plane[1].diag_mc;
 527             s->plane[2].htaps  = s->plane[1].htaps;
 528             memcpy(s->plane[2].hcoeff, s->plane[1].hcoeff, sizeof(s->plane[1].hcoeff));
 529         }
 530         if(get_rac(&s->c, s->header_state)){
 531             GET_S(s->spatial_decomposition_count, 0 < tmp && tmp <= MAX_DECOMPOSITIONS)
 532             decode_qlogs(s);
 533         }
 534     }
 535
 536     s->spatial_decomposition_type+= (unsigned)get_symbol(&s->c, s->header_state, 1);
 537     if(s->spatial_decomposition_type > 1U){
 538         av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_type %d not supported\n", s->spatial_decomposition_type);
 539         return AVERROR_INVALIDDATA;
 540     }
 541     if(FFMIN(s->avctx-> width>>s->chroma_h_shift,
 542              s->avctx->height>>s->chroma_v_shift) >> (s->spatial_decomposition_count-1) <= 1){
 543         av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_count %d too large for size\n", s->spatial_decomposition_count);
 544         return AVERROR_INVALIDDATA;
 545     }
 546     if (s->avctx->width > 65536-4) {
 547         av_log(s->avctx, AV_LOG_ERROR, "Width %d is too large\n", s->avctx->width);
 548         return AVERROR_INVALIDDATA;
 549     }
 550
 551
 552     s->qlog           += (unsigned)get_symbol(&s->c, s->header_state, 1);
 553     s->mv_scale       += (unsigned)get_symbol(&s->c, s->header_state, 1);
 554     s->qbias          += (unsigned)get_symbol(&s->c, s->header_state, 1);
 555     s->block_max_depth+= (unsigned)get_symbol(&s->c, s->header_state, 1);
 556     if(s->block_max_depth > 1 || s->block_max_depth < 0 || s->mv_scale > 256U){
 557         av_log(s->avctx, AV_LOG_ERROR, "block_max_depth= %d is too large\n", s->block_max_depth);
 558         s->block_max_depth= 0;
 559         s->mv_scale = 0;
 560         return AVERROR_INVALIDDATA;
 561     }
 562     if (FFABS(s->qbias) > 127) {
 563         av_log(s->avctx, AV_LOG_ERROR, "qbias %d is too large\n", s->qbias);
 564         s->qbias = 0;
 565         return AVERROR_INVALIDDATA;
 566     }
 567
 568     return 0;
 569 }
 570
 571 static int decode_blocks(SnowContext *s){
 572     int x, y;
 573     int w= s->b_width;
 574     int h= s->b_height;
 575     int res;
 576
 577     for(y=0; y<h; y++){
 578         for(x=0; x<w; x++){
 579             if (s->c.bytestream >= s->c.bytestream_end)
 580                 return AVERROR_INVALIDDATA;
 581             if ((res = decode_q_branch(s, 0, x, y)) < 0)
 582                 return res;
 583         }
 584     }
 585     return 0;
 586 }
 587
 588 static int decode_frame(AVCodecContext *avctx, AVFrame *picture,
 589                         int *got_frame, AVPacket *avpkt)
 590 {
 591     const uint8_t *buf = avpkt->data;
 592     int buf_size = avpkt->size;
 593     SnowContext *s = avctx->priv_data;
 594     RangeCoder * const c= &s->c;
 595     int bytes_read;
 596     int level, orientation, plane_index;
 597     int res;
 598
 599     ff_init_range_decoder(c, buf, buf_size);
 600     ff_build_rac_states(c, 0.05*(1LL<<32), 256-8);
 601
 602     s->current_picture->pict_type= AV_PICTURE_TYPE_I; //FIXME I vs. P
 603     if ((res = decode_header(s)) < 0)
 604         return res;
 605
 606     if (!s->mconly_picture->data[0]) {
 607         res = ff_get_buffer(avctx, s->mconly_picture, AV_GET_BUFFER_FLAG_REF);
 608         if (res < 0)
 609             return res;
 610     }
 611     if (s->mconly_picture->format != avctx->pix_fmt) {
 612         av_log(avctx, AV_LOG_ERROR, "pixel format changed\n");
 613         return AVERROR_INVALIDDATA;
 614     }
 615
 616     if ((res=ff_snow_common_init_after_header(avctx)) < 0)
 617         return res;
 618
 619     // realloc slice buffer for the case that spatial_decomposition_count changed
 620     ff_slice_buffer_destroy(&s->sb);
 621     if ((res = ff_slice_buffer_init(&s->sb, s->plane[0].height,
 622                                     (MB_SIZE >> s->block_max_depth) +
 623                                     s->spatial_decomposition_count * 11 + 1,
 624                                     s->plane[0].width,
 625                                     s->spatial_idwt_buffer)) < 0)
 626         return res;
 627
 628     for(plane_index=0; plane_index < s->nb_planes; plane_index++){
 629         Plane *p= &s->plane[plane_index];
 630         p->fast_mc= p->diag_mc && p->htaps==6 && p->hcoeff[0]==40
 631                                               && p->hcoeff[1]==-10
 632                                               && p->hcoeff[2]==2;
 633     }
 634
 635     ff_snow_alloc_blocks(s);
 636
 637     if ((res = ff_snow_frames_prepare(s)) < 0)
 638         return res;
 639
 640     s->current_picture->width  = s->avctx->width;
 641     s->current_picture->height = s->avctx->height;
 642     res = ff_get_buffer(s->avctx, s->current_picture, AV_GET_BUFFER_FLAG_REF);
 643     if (res < 0)
 644         return res;
 645
 646     s->current_picture->pict_type = s->keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
 647
 648     //keyframe flag duplication mess FIXME
 649     if(avctx->debug&FF_DEBUG_PICT_INFO)
 650         av_log(avctx, AV_LOG_ERROR,
 651                "keyframe:%d qlog:%d qbias: %d mvscale: %d "
 652                "decomposition_type:%d decomposition_count:%d\n",
 653                s->keyframe, s->qlog, s->qbias, s->mv_scale,
 654                s->spatial_decomposition_type,
 655                s->spatial_decomposition_count
 656               );
 657
 658     if (s->avctx->export_side_data & AV_CODEC_EXPORT_DATA_MVS) {
 659         size_t size;
 660         res = av_size_mult(s->b_width * s->b_height, sizeof(AVMotionVector) << (s->block_max_depth*2), &size);
 661         if (res)
 662             return res;
 663         av_fast_malloc(&s->avmv, &s->avmv_size, size);
 664         if (!s->avmv)
 665             return AVERROR(ENOMEM);
 666     } else {
 667         s->avmv_size = 0;
 668         av_freep(&s->avmv);
 669     }
 670     s->avmv_index = 0;
 671
 672     if ((res = decode_blocks(s)) < 0)
 673         return res;
 674
 675     for(plane_index=0; plane_index < s->nb_planes; plane_index++){
 676         Plane *p= &s->plane[plane_index];
 677         int w= p->width;
 678         int h= p->height;
 679         int x, y;
 680         int decode_state[MAX_DECOMPOSITIONS][4][1]; /* Stored state info for unpack_coeffs. 1 variable per instance. */
 681
 682         if(s->avctx->debug&2048){
 683             memset(s->spatial_dwt_buffer, 0, sizeof(DWTELEM)*w*h);
 684             predict_plane(s, s->spatial_idwt_buffer, plane_index, 1);
 685
 686             for(y=0; y<h; y++){
 687                 for(x=0; x<w; x++){
 688                     int v= s->current_picture->data[plane_index][y*s->current_picture->linesize[plane_index] + x];
 689                     s->mconly_picture->data[plane_index][y*s->mconly_picture->linesize[plane_index] + x]= v;
 690                 }
 691             }
 692         }
 693
 694         for(level=0; level<s->spatial_decomposition_count; level++){
 695             for(orientation=level ? 1 : 0; orientation<4; orientation++){
 696                 SubBand *b= &p->band[level][orientation];
 697                 unpack_coeffs(s, b, b->parent, orientation);
 698             }
 699         }
 700
 701         {
 702         const int mb_h= s->b_height << s->block_max_depth;
 703         const int block_size = MB_SIZE >> s->block_max_depth;
 704         const int block_h    = plane_index ? block_size>>s->chroma_v_shift : block_size;
 705         int mb_y;
 706         DWTCompose cs[MAX_DECOMPOSITIONS];
 707         int yd=0, yq=0;
 708         int y;
 709         int end_y;
 710
 711         ff_spatial_idwt_buffered_init(cs, &s->sb, w, h, 1, s->spatial_decomposition_type, s->spatial_decomposition_count);
 712         for(mb_y=0; mb_y<=mb_h; mb_y++){
 713
 714             int slice_starty = block_h*mb_y;
 715             int slice_h = block_h*(mb_y+1);
 716
 717             if (!(s->keyframe || s->avctx->debug&512)){
 718                 slice_starty = FFMAX(0, slice_starty - (block_h >> 1));
 719                 slice_h -= (block_h >> 1);
 720             }
 721
 722             for(level=0; level<s->spatial_decomposition_count; level++){
 723                 for(orientation=level ? 1 : 0; orientation<4; orientation++){
 724                     SubBand *b= &p->band[level][orientation];
 725                     int start_y;
 726                     int end_y;
 727                     int our_mb_start = mb_y;
 728                     int our_mb_end = (mb_y + 1);
 729                     const int extra= 3;
 730                     start_y = (mb_y ? ((block_h * our_mb_start) >> (s->spatial_decomposition_count - level)) + s->spatial_decomposition_count - level + extra: 0);
 731                     end_y = (((block_h * our_mb_end) >> (s->spatial_decomposition_count - level)) + s->spatial_decomposition_count - level + extra);
 732                     if (!(s->keyframe || s->avctx->debug&512)){
 733                         start_y = FFMAX(0, start_y - (block_h >> (1+s->spatial_decomposition_count - level)));
 734                         end_y = FFMAX(0, end_y - (block_h >> (1+s->spatial_decomposition_count - level)));
 735                     }
 736                     start_y = FFMIN(b->height, start_y);
 737                     end_y = FFMIN(b->height, end_y);
 738
 739                     if (start_y != end_y){
 740                         if (orientation == 0){
 741                             SubBand * correlate_band = &p->band[0][0];
 742                             int correlate_end_y = FFMIN(b->height, end_y + 1);
 743                             int correlate_start_y = FFMIN(b->height, (start_y ? start_y + 1 : 0));
 744                             decode_subband_slice_buffered(s, correlate_band, &s->sb, correlate_start_y, correlate_end_y, decode_state[0][0]);
 745                             correlate_slice_buffered(s, &s->sb, correlate_band, correlate_band->ibuf, correlate_band->stride, 1, 0, correlate_start_y, correlate_end_y);
 746                             dequantize_slice_buffered(s, &s->sb, correlate_band, correlate_band->ibuf, correlate_band->stride, start_y, end_y);
 747                         }
 748                         else
 749                             decode_subband_slice_buffered(s, b, &s->sb, start_y, end_y, decode_state[level][orientation]);
 750                     }
 751                 }
 752             }
 753
 754             for(; yd<slice_h; yd+=4){
 755                 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);
 756             }
 757
 758             if(s->qlog == LOSSLESS_QLOG){
 759                 for(; yq<slice_h && yq<h; yq++){
 760                     IDWTELEM * line = slice_buffer_get_line(&s->sb, yq);
 761                     for(x=0; x<w; x++){
 762                         line[x] *= 1<<FRAC_BITS;
 763                     }
 764                 }
 765             }
 766
 767             predict_slice_buffered(s, &s->sb, s->spatial_idwt_buffer, plane_index, 1, mb_y);
 768
 769             y = FFMIN(p->height, slice_starty);
 770             end_y = FFMIN(p->height, slice_h);
 771             while(y < end_y)
 772                 ff_slice_buffer_release(&s->sb, y++);
 773         }
 774
 775         ff_slice_buffer_flush(&s->sb);
 776         }
 777
 778     }
 779
 780     emms_c();
 781
 782     ff_snow_release_buffer(avctx);
 783
 784     if(!(s->avctx->debug&2048))
 785         res = av_frame_ref(picture, s->current_picture);
 786     else
 787         res = av_frame_ref(picture, s->mconly_picture);
 788     if (res >= 0 && s->avmv_index) {
 789         AVFrameSideData *sd;
 790
 791         sd = av_frame_new_side_data(picture, AV_FRAME_DATA_MOTION_VECTORS, s->avmv_index * sizeof(AVMotionVector));
 792         if (!sd)
 793             return AVERROR(ENOMEM);
 794         memcpy(sd->data, s->avmv, s->avmv_index * sizeof(AVMotionVector));
 795     }
 796
 797     if (res < 0)
 798         return res;
 799
 800     *got_frame = 1;
 801
 802     bytes_read= c->bytestream - c->bytestream_start;
 803     if(bytes_read ==0) av_log(s->avctx, AV_LOG_ERROR, "error at end of frame\n"); //FIXME
 804
 805     return bytes_read;
 806 }
 807
 808 static av_cold int decode_end(AVCodecContext *avctx)
 809 {
 810     SnowContext *s = avctx->priv_data;
 811
 812     ff_slice_buffer_destroy(&s->sb);
 813
 814     ff_snow_common_end(s);
 815
 816     s->avmv_size = 0;
 817     av_freep(&s->avmv);
 818
 819     return 0;
 820 }
 821
 822 const FFCodec ff_snow_decoder = {
 823     .p.name         = "snow",
 824     CODEC_LONG_NAME("Snow"),
 825     .p.type         = AVMEDIA_TYPE_VIDEO,
 826     .p.id           = AV_CODEC_ID_SNOW,
 827     .priv_data_size = sizeof(SnowContext),
 828     .init           = ff_snow_common_init,
 829     .close          = decode_end,
 830     FF_CODEC_DECODE_CB(decode_frame),
 831     .p.capabilities = AV_CODEC_CAP_DR1,
 832     .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
 833 };