avcodec/gsmdec_template: Fix runtime error: signed integer overflow: -22527 * 99113...
[ffmpeg.git] / 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 "snow_dwt.h"
26 #include "internal.h"
27 #include "snow.h"
28
29 #include "rangecoder.h"
30 #include "mathops.h"
31
32 #include "mpegvideo.h"
33 #include "h263.h"
34
35 static av_always_inline void predict_slice_buffered(SnowContext *s, slice_buffer * sb, IDWTELEM * old_buffer, int plane_index, int add, int mb_y){
36     Plane *p= &s->plane[plane_index];
37     const int mb_w= s->b_width  << s->block_max_depth;
38     const int mb_h= s->b_height << s->block_max_depth;
39     int x, y, mb_x;
40     int block_size = MB_SIZE >> s->block_max_depth;
41     int block_w    = plane_index ? block_size>>s->chroma_h_shift : block_size;
42     int block_h    = plane_index ? block_size>>s->chroma_v_shift : block_size;
43     const uint8_t *obmc  = plane_index ? ff_obmc_tab[s->block_max_depth+s->chroma_h_shift] : ff_obmc_tab[s->block_max_depth];
44     int obmc_stride= plane_index ? (2*block_size)>>s->chroma_h_shift : 2*block_size;
45     int ref_stride= s->current_picture->linesize[plane_index];
46     uint8_t *dst8= s->current_picture->data[plane_index];
47     int w= p->width;
48     int h= p->height;
49
50     if(s->keyframe || (s->avctx->debug&512)){
51         if(mb_y==mb_h)
52             return;
53
54         if(add){
55             for(y=block_h*mb_y; y<FFMIN(h,block_h*(mb_y+1)); y++){
56 //                DWTELEM * line = slice_buffer_get_line(sb, y);
57                 IDWTELEM * line = sb->line[y];
58                 for(x=0; x<w; x++){
59 //                    int v= buf[x + y*w] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
60                     int v= line[x] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
61                     v >>= FRAC_BITS;
62                     if(v&(~255)) v= ~(v>>31);
63                     dst8[x + y*ref_stride]= v;
64                 }
65             }
66         }else{
67             for(y=block_h*mb_y; y<FFMIN(h,block_h*(mb_y+1)); y++){
68 //                DWTELEM * line = slice_buffer_get_line(sb, y);
69                 IDWTELEM * line = sb->line[y];
70                 for(x=0; x<w; x++){
71                     line[x] -= 128 << FRAC_BITS;
72 //                    buf[x + y*w]-= 128<<FRAC_BITS;
73                 }
74             }
75         }
76
77         return;
78     }
79
80     for(mb_x=0; mb_x<=mb_w; mb_x++){
81         add_yblock(s, 1, sb, old_buffer, dst8, obmc,
82                    block_w*mb_x - block_w/2,
83                    block_h*mb_y - block_h/2,
84                    block_w, block_h,
85                    w, h,
86                    w, ref_stride, obmc_stride,
87                    mb_x - 1, mb_y - 1,
88                    add, 0, plane_index);
89     }
90
91     if(s->avmv && mb_y < mb_h && plane_index == 0)
92         for(mb_x=0; mb_x<mb_w; mb_x++){
93             AVMotionVector *avmv = s->avmv + s->avmv_index;
94             const int b_width = s->b_width  << s->block_max_depth;
95             const int b_stride= b_width;
96             BlockNode *bn= &s->block[mb_x + mb_y*b_stride];
97
98             if (bn->type)
99                 continue;
100
101             s->avmv_index++;
102
103             avmv->w = block_w;
104             avmv->h = block_h;
105             avmv->dst_x = block_w*mb_x - block_w/2;
106             avmv->dst_y = block_h*mb_y - block_h/2;
107             avmv->motion_scale = 8;
108             avmv->motion_x = bn->mx * s->mv_scale;
109             avmv->motion_y = bn->my * s->mv_scale;
110             avmv->src_x = avmv->dst_x + avmv->motion_x / 8;
111             avmv->src_y = avmv->dst_y + avmv->motion_y / 8;
112             avmv->source= -1 - bn->ref;
113             avmv->flags = 0;
114         }
115 }
116
117 static inline void decode_subband_slice_buffered(SnowContext *s, SubBand *b, slice_buffer * sb, int start_y, int h, int save_state[1]){
118     const int w= b->width;
119     int y;
120     const int qlog= av_clip(s->qlog + b->qlog, 0, QROOT*16);
121     int qmul= ff_qexp[qlog&(QROOT-1)]<<(qlog>>QSHIFT);
122     int qadd= (s->qbias*qmul)>>QBIAS_SHIFT;
123     int new_index = 0;
124
125     if(b->ibuf == s->spatial_idwt_buffer || s->qlog == LOSSLESS_QLOG){
126         qadd= 0;
127         qmul= 1<<QEXPSHIFT;
128     }
129
130     /* If we are on the second or later slice, restore our index. */
131     if (start_y != 0)
132         new_index = save_state[0];
133
134
135     for(y=start_y; y<h; y++){
136         int x = 0;
137         int v;
138         IDWTELEM * line = slice_buffer_get_line(sb, y * b->stride_line + b->buf_y_offset) + b->buf_x_offset;
139         memset(line, 0, b->width*sizeof(IDWTELEM));
140         v = b->x_coeff[new_index].coeff;
141         x = b->x_coeff[new_index++].x;
142         while(x < w){
143             register int t= ( (v>>1)*qmul + qadd)>>QEXPSHIFT;
144             register int u= -(v&1);
145             line[x] = (t^u) - u;
146
147             v = b->x_coeff[new_index].coeff;
148             x = b->x_coeff[new_index++].x;
149         }
150     }
151
152     /* Save our variables for the next slice. */
153     save_state[0] = new_index;
154
155     return;
156 }
157
158 static int decode_q_branch(SnowContext *s, int level, int x, int y){
159     const int w= s->b_width << s->block_max_depth;
160     const int rem_depth= s->block_max_depth - level;
161     const int index= (x + y*w) << rem_depth;
162     int trx= (x+1)<<rem_depth;
163     const BlockNode *left  = x ? &s->block[index-1] : &null_block;
164     const BlockNode *top   = y ? &s->block[index-w] : &null_block;
165     const BlockNode *tl    = y && x ? &s->block[index-w-1] : left;
166     const BlockNode *tr    = y && trx<w && ((x&1)==0 || level==0) ? &s->block[index-w+(1<<rem_depth)] : tl; //FIXME use lt
167     int s_context= 2*left->level + 2*top->level + tl->level + tr->level;
168     int res;
169
170     if(s->keyframe){
171         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);
172         return 0;
173     }
174
175     if(level==s->block_max_depth || get_rac(&s->c, &s->block_state[4 + s_context])){
176         int type, mx, my;
177         int l = left->color[0];
178         int cb= left->color[1];
179         int cr= left->color[2];
180         unsigned ref = 0;
181         int ref_context= av_log2(2*left->ref) + av_log2(2*top->ref);
182         int mx_context= av_log2(2*FFABS(left->mx - top->mx)) + 0*av_log2(2*FFABS(tr->mx - top->mx));
183         int my_context= av_log2(2*FFABS(left->my - top->my)) + 0*av_log2(2*FFABS(tr->my - top->my));
184
185         type= get_rac(&s->c, &s->block_state[1 + left->type + top->type]) ? BLOCK_INTRA : 0;
186
187         if(type){
188             pred_mv(s, &mx, &my, 0, left, top, tr);
189             l += get_symbol(&s->c, &s->block_state[32], 1);
190             if (s->nb_planes > 2) {
191                 cb+= get_symbol(&s->c, &s->block_state[64], 1);
192                 cr+= get_symbol(&s->c, &s->block_state[96], 1);
193             }
194         }else{
195             if(s->ref_frames > 1)
196                 ref= get_symbol(&s->c, &s->block_state[128 + 1024 + 32*ref_context], 0);
197             if (ref >= s->ref_frames) {
198                 av_log(s->avctx, AV_LOG_ERROR, "Invalid ref\n");
199                 return AVERROR_INVALIDDATA;
200             }
201             pred_mv(s, &mx, &my, ref, left, top, tr);
202             mx+= get_symbol(&s->c, &s->block_state[128 + 32*(mx_context + 16*!!ref)], 1);
203             my+= get_symbol(&s->c, &s->block_state[128 + 32*(my_context + 16*!!ref)], 1);
204         }
205         set_blocks(s, level, x, y, l, cb, cr, mx, my, ref, type);
206     }else{
207         if ((res = decode_q_branch(s, level+1, 2*x+0, 2*y+0)) < 0 ||
208             (res = decode_q_branch(s, level+1, 2*x+1, 2*y+0)) < 0 ||
209             (res = decode_q_branch(s, level+1, 2*x+0, 2*y+1)) < 0 ||
210             (res = decode_q_branch(s, level+1, 2*x+1, 2*y+1)) < 0)
211             return res;
212     }
213     return 0;
214 }
215
216 static void dequantize_slice_buffered(SnowContext *s, slice_buffer * sb, SubBand *b, IDWTELEM *src, int stride, int start_y, int end_y){
217     const int w= b->width;
218     const int qlog= av_clip(s->qlog + b->qlog, 0, QROOT*16);
219     const int qmul= ff_qexp[qlog&(QROOT-1)]<<(qlog>>QSHIFT);
220     const int qadd= (s->qbias*qmul)>>QBIAS_SHIFT;
221     int x,y;
222
223     if(s->qlog == LOSSLESS_QLOG) return;
224
225     for(y=start_y; y<end_y; y++){
226 //        DWTELEM * line = slice_buffer_get_line_from_address(sb, src + (y * stride));
227         IDWTELEM * line = slice_buffer_get_line(sb, (y * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
228         for(x=0; x<w; x++){
229             int i= line[x];
230             if(i<0){
231                 line[x]= -((-i*qmul + qadd)>>(QEXPSHIFT)); //FIXME try different bias
232             }else if(i>0){
233                 line[x]=  (( i*qmul + qadd)>>(QEXPSHIFT));
234             }
235         }
236     }
237 }
238
239 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){
240     const int w= b->width;
241     int x,y;
242
243     IDWTELEM * line=0; // silence silly "could be used without having been initialized" warning
244     IDWTELEM * prev;
245
246     if (start_y != 0)
247         line = slice_buffer_get_line(sb, ((start_y - 1) * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
248
249     for(y=start_y; y<end_y; y++){
250         prev = line;
251 //        line = slice_buffer_get_line_from_address(sb, src + (y * stride));
252         line = slice_buffer_get_line(sb, (y * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
253         for(x=0; x<w; x++){
254             if(x){
255                 if(use_median){
256                     if(y && x+1<w) line[x] += mid_pred(line[x - 1], prev[x], prev[x + 1]);
257                     else  line[x] += line[x - 1];
258                 }else{
259                     if(y) line[x] += mid_pred(line[x - 1], prev[x], line[x - 1] + prev[x] - prev[x - 1]);
260                     else  line[x] += line[x - 1];
261                 }
262             }else{
263                 if(y) line[x] += prev[x];
264             }
265         }
266     }
267 }
268
269 static void decode_qlogs(SnowContext *s){
270     int plane_index, level, orientation;
271
272     for(plane_index=0; plane_index < s->nb_planes; plane_index++){
273         for(level=0; level<s->spatial_decomposition_count; level++){
274             for(orientation=level ? 1:0; orientation<4; orientation++){
275                 int q;
276                 if     (plane_index==2) q= s->plane[1].band[level][orientation].qlog;
277                 else if(orientation==2) q= s->plane[plane_index].band[level][1].qlog;
278                 else                    q= get_symbol(&s->c, s->header_state, 1);
279                 s->plane[plane_index].band[level][orientation].qlog= q;
280             }
281         }
282     }
283 }
284
285 #define GET_S(dst, check) \
286     tmp= get_symbol(&s->c, s->header_state, 0);\
287     if(!(check)){\
288         av_log(s->avctx, AV_LOG_ERROR, "Error " #dst " is %d\n", tmp);\
289         return AVERROR_INVALIDDATA;\
290     }\
291     dst= tmp;
292
293 static int decode_header(SnowContext *s){
294     int plane_index, tmp;
295     uint8_t kstate[32];
296
297     memset(kstate, MID_STATE, sizeof(kstate));
298
299     s->keyframe= get_rac(&s->c, kstate);
300     if(s->keyframe || s->always_reset){
301         ff_snow_reset_contexts(s);
302         s->spatial_decomposition_type=
303         s->qlog=
304         s->qbias=
305         s->mv_scale=
306         s->block_max_depth= 0;
307     }
308     if(s->keyframe){
309         GET_S(s->version, tmp <= 0U)
310         s->always_reset= get_rac(&s->c, s->header_state);
311         s->temporal_decomposition_type= get_symbol(&s->c, s->header_state, 0);
312         s->temporal_decomposition_count= get_symbol(&s->c, s->header_state, 0);
313         GET_S(s->spatial_decomposition_count, 0 < tmp && tmp <= MAX_DECOMPOSITIONS)
314         s->colorspace_type= get_symbol(&s->c, s->header_state, 0);
315         if (s->colorspace_type == 1) {
316             s->avctx->pix_fmt= AV_PIX_FMT_GRAY8;
317             s->nb_planes = 1;
318         } else if(s->colorspace_type == 0) {
319             s->chroma_h_shift= get_symbol(&s->c, s->header_state, 0);
320             s->chroma_v_shift= get_symbol(&s->c, s->header_state, 0);
321
322             if(s->chroma_h_shift == 1 && s->chroma_v_shift==1){
323                 s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
324             }else if(s->chroma_h_shift == 0 && s->chroma_v_shift==0){
325                 s->avctx->pix_fmt= AV_PIX_FMT_YUV444P;
326             }else if(s->chroma_h_shift == 2 && s->chroma_v_shift==2){
327                 s->avctx->pix_fmt= AV_PIX_FMT_YUV410P;
328             } else {
329                 av_log(s, AV_LOG_ERROR, "unsupported color subsample mode %d %d\n", s->chroma_h_shift, s->chroma_v_shift);
330                 s->chroma_h_shift = s->chroma_v_shift = 1;
331                 s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
332                 return AVERROR_INVALIDDATA;
333             }
334             s->nb_planes = 3;
335         } else {
336             av_log(s, AV_LOG_ERROR, "unsupported color space\n");
337             s->chroma_h_shift = s->chroma_v_shift = 1;
338             s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
339             return AVERROR_INVALIDDATA;
340         }
341
342
343         s->spatial_scalability= get_rac(&s->c, s->header_state);
344 //        s->rate_scalability= get_rac(&s->c, s->header_state);
345         GET_S(s->max_ref_frames, tmp < (unsigned)MAX_REF_FRAMES)
346         s->max_ref_frames++;
347
348         decode_qlogs(s);
349     }
350
351     if(!s->keyframe){
352         if(get_rac(&s->c, s->header_state)){
353             for(plane_index=0; plane_index<FFMIN(s->nb_planes, 2); plane_index++){
354                 int htaps, i, sum=0;
355                 Plane *p= &s->plane[plane_index];
356                 p->diag_mc= get_rac(&s->c, s->header_state);
357                 htaps= get_symbol(&s->c, s->header_state, 0)*2 + 2;
358                 if((unsigned)htaps > HTAPS_MAX || htaps==0)
359                     return AVERROR_INVALIDDATA;
360                 p->htaps= htaps;
361                 for(i= htaps/2; i; i--){
362                     p->hcoeff[i]= get_symbol(&s->c, s->header_state, 0) * (1-2*(i&1));
363                     sum += p->hcoeff[i];
364                 }
365                 p->hcoeff[0]= 32-sum;
366             }
367             s->plane[2].diag_mc= s->plane[1].diag_mc;
368             s->plane[2].htaps  = s->plane[1].htaps;
369             memcpy(s->plane[2].hcoeff, s->plane[1].hcoeff, sizeof(s->plane[1].hcoeff));
370         }
371         if(get_rac(&s->c, s->header_state)){
372             GET_S(s->spatial_decomposition_count, 0 < tmp && tmp <= MAX_DECOMPOSITIONS)
373             decode_qlogs(s);
374         }
375     }
376
377     s->spatial_decomposition_type+= get_symbol(&s->c, s->header_state, 1);
378     if(s->spatial_decomposition_type > 1U){
379         av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_type %d not supported\n", s->spatial_decomposition_type);
380         return AVERROR_INVALIDDATA;
381     }
382     if(FFMIN(s->avctx-> width>>s->chroma_h_shift,
383              s->avctx->height>>s->chroma_v_shift) >> (s->spatial_decomposition_count-1) <= 1){
384         av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_count %d too large for size\n", s->spatial_decomposition_count);
385         return AVERROR_INVALIDDATA;
386     }
387
388
389     s->qlog           += get_symbol(&s->c, s->header_state, 1);
390     s->mv_scale       += get_symbol(&s->c, s->header_state, 1);
391     s->qbias          += get_symbol(&s->c, s->header_state, 1);
392     s->block_max_depth+= get_symbol(&s->c, s->header_state, 1);
393     if(s->block_max_depth > 1 || s->block_max_depth < 0){
394         av_log(s->avctx, AV_LOG_ERROR, "block_max_depth= %d is too large\n", s->block_max_depth);
395         s->block_max_depth= 0;
396         return AVERROR_INVALIDDATA;
397     }
398
399     return 0;
400 }
401
402 static av_cold int decode_init(AVCodecContext *avctx)
403 {
404     int ret;
405
406     if ((ret = ff_snow_common_init(avctx)) < 0) {
407         return ret;
408     }
409
410     return 0;
411 }
412
413 static int decode_blocks(SnowContext *s){
414     int x, y;
415     int w= s->b_width;
416     int h= s->b_height;
417     int res;
418
419     for(y=0; y<h; y++){
420         for(x=0; x<w; x++){
421             if ((res = decode_q_branch(s, 0, x, y)) < 0)
422                 return res;
423         }
424     }
425     return 0;
426 }
427
428 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
429                         AVPacket *avpkt)
430 {
431     const uint8_t *buf = avpkt->data;
432     int buf_size = avpkt->size;
433     SnowContext *s = avctx->priv_data;
434     RangeCoder * const c= &s->c;
435     int bytes_read;
436     AVFrame *picture = data;
437     int level, orientation, plane_index;
438     int res;
439
440     ff_init_range_decoder(c, buf, buf_size);
441     ff_build_rac_states(c, 0.05*(1LL<<32), 256-8);
442
443     s->current_picture->pict_type= AV_PICTURE_TYPE_I; //FIXME I vs. P
444     if ((res = decode_header(s)) < 0)
445         return res;
446     if ((res=ff_snow_common_init_after_header(avctx)) < 0)
447         return res;
448
449     // realloc slice buffer for the case that spatial_decomposition_count changed
450     ff_slice_buffer_destroy(&s->sb);
451     if ((res = ff_slice_buffer_init(&s->sb, s->plane[0].height,
452                                     (MB_SIZE >> s->block_max_depth) +
453                                     s->spatial_decomposition_count * 11 + 1,
454                                     s->plane[0].width,
455                                     s->spatial_idwt_buffer)) < 0)
456         return res;
457
458     for(plane_index=0; plane_index < s->nb_planes; plane_index++){
459         Plane *p= &s->plane[plane_index];
460         p->fast_mc= p->diag_mc && p->htaps==6 && p->hcoeff[0]==40
461                                               && p->hcoeff[1]==-10
462                                               && p->hcoeff[2]==2;
463     }
464
465     ff_snow_alloc_blocks(s);
466
467     if((res = ff_snow_frame_start(s)) < 0)
468         return res;
469
470     s->current_picture->pict_type = s->keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
471
472     //keyframe flag duplication mess FIXME
473     if(avctx->debug&FF_DEBUG_PICT_INFO)
474         av_log(avctx, AV_LOG_ERROR,
475                "keyframe:%d qlog:%d qbias: %d mvscale: %d "
476                "decomposition_type:%d decomposition_count:%d\n",
477                s->keyframe, s->qlog, s->qbias, s->mv_scale,
478                s->spatial_decomposition_type,
479                s->spatial_decomposition_count
480               );
481
482     av_assert0(!s->avmv);
483     if (s->avctx->flags2 & AV_CODEC_FLAG2_EXPORT_MVS) {
484         s->avmv = av_malloc_array(s->b_width * s->b_height, sizeof(AVMotionVector) << (s->block_max_depth*2));
485     }
486     s->avmv_index = 0;
487
488     if ((res = decode_blocks(s)) < 0)
489         return res;
490
491     for(plane_index=0; plane_index < s->nb_planes; plane_index++){
492         Plane *p= &s->plane[plane_index];
493         int w= p->width;
494         int h= p->height;
495         int x, y;
496         int decode_state[MAX_DECOMPOSITIONS][4][1]; /* Stored state info for unpack_coeffs. 1 variable per instance. */
497
498         if(s->avctx->debug&2048){
499             memset(s->spatial_dwt_buffer, 0, sizeof(DWTELEM)*w*h);
500             predict_plane(s, s->spatial_idwt_buffer, plane_index, 1);
501
502             for(y=0; y<h; y++){
503                 for(x=0; x<w; x++){
504                     int v= s->current_picture->data[plane_index][y*s->current_picture->linesize[plane_index] + x];
505                     s->mconly_picture->data[plane_index][y*s->mconly_picture->linesize[plane_index] + x]= v;
506                 }
507             }
508         }
509
510         {
511         for(level=0; level<s->spatial_decomposition_count; level++){
512             for(orientation=level ? 1 : 0; orientation<4; orientation++){
513                 SubBand *b= &p->band[level][orientation];
514                 unpack_coeffs(s, b, b->parent, orientation);
515             }
516         }
517         }
518
519         {
520         const int mb_h= s->b_height << s->block_max_depth;
521         const int block_size = MB_SIZE >> s->block_max_depth;
522         const int block_h    = plane_index ? block_size>>s->chroma_v_shift : block_size;
523         int mb_y;
524         DWTCompose cs[MAX_DECOMPOSITIONS];
525         int yd=0, yq=0;
526         int y;
527         int end_y;
528
529         ff_spatial_idwt_buffered_init(cs, &s->sb, w, h, 1, s->spatial_decomposition_type, s->spatial_decomposition_count);
530         for(mb_y=0; mb_y<=mb_h; mb_y++){
531
532             int slice_starty = block_h*mb_y;
533             int slice_h = block_h*(mb_y+1);
534
535             if (!(s->keyframe || s->avctx->debug&512)){
536                 slice_starty = FFMAX(0, slice_starty - (block_h >> 1));
537                 slice_h -= (block_h >> 1);
538             }
539
540             for(level=0; level<s->spatial_decomposition_count; level++){
541                 for(orientation=level ? 1 : 0; orientation<4; orientation++){
542                     SubBand *b= &p->band[level][orientation];
543                     int start_y;
544                     int end_y;
545                     int our_mb_start = mb_y;
546                     int our_mb_end = (mb_y + 1);
547                     const int extra= 3;
548                     start_y = (mb_y ? ((block_h * our_mb_start) >> (s->spatial_decomposition_count - level)) + s->spatial_decomposition_count - level + extra: 0);
549                     end_y = (((block_h * our_mb_end) >> (s->spatial_decomposition_count - level)) + s->spatial_decomposition_count - level + extra);
550                     if (!(s->keyframe || s->avctx->debug&512)){
551                         start_y = FFMAX(0, start_y - (block_h >> (1+s->spatial_decomposition_count - level)));
552                         end_y = FFMAX(0, end_y - (block_h >> (1+s->spatial_decomposition_count - level)));
553                     }
554                     start_y = FFMIN(b->height, start_y);
555                     end_y = FFMIN(b->height, end_y);
556
557                     if (start_y != end_y){
558                         if (orientation == 0){
559                             SubBand * correlate_band = &p->band[0][0];
560                             int correlate_end_y = FFMIN(b->height, end_y + 1);
561                             int correlate_start_y = FFMIN(b->height, (start_y ? start_y + 1 : 0));
562                             decode_subband_slice_buffered(s, correlate_band, &s->sb, correlate_start_y, correlate_end_y, decode_state[0][0]);
563                             correlate_slice_buffered(s, &s->sb, correlate_band, correlate_band->ibuf, correlate_band->stride, 1, 0, correlate_start_y, correlate_end_y);
564                             dequantize_slice_buffered(s, &s->sb, correlate_band, correlate_band->ibuf, correlate_band->stride, start_y, end_y);
565                         }
566                         else
567                             decode_subband_slice_buffered(s, b, &s->sb, start_y, end_y, decode_state[level][orientation]);
568                     }
569                 }
570             }
571
572             for(; yd<slice_h; yd+=4){
573                 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);
574             }
575
576             if(s->qlog == LOSSLESS_QLOG){
577                 for(; yq<slice_h && yq<h; yq++){
578                     IDWTELEM * line = slice_buffer_get_line(&s->sb, yq);
579                     for(x=0; x<w; x++){
580                         line[x] <<= FRAC_BITS;
581                     }
582                 }
583             }
584
585             predict_slice_buffered(s, &s->sb, s->spatial_idwt_buffer, plane_index, 1, mb_y);
586
587             y = FFMIN(p->height, slice_starty);
588             end_y = FFMIN(p->height, slice_h);
589             while(y < end_y)
590                 ff_slice_buffer_release(&s->sb, y++);
591         }
592
593         ff_slice_buffer_flush(&s->sb);
594         }
595
596     }
597
598     emms_c();
599
600     ff_snow_release_buffer(avctx);
601
602     if(!(s->avctx->debug&2048))
603         res = av_frame_ref(picture, s->current_picture);
604     else
605         res = av_frame_ref(picture, s->mconly_picture);
606     if (res >= 0 && s->avmv_index) {
607         AVFrameSideData *sd;
608
609         sd = av_frame_new_side_data(picture, AV_FRAME_DATA_MOTION_VECTORS, s->avmv_index * sizeof(AVMotionVector));
610         if (!sd)
611             return AVERROR(ENOMEM);
612         memcpy(sd->data, s->avmv, s->avmv_index * sizeof(AVMotionVector));
613     }
614
615     av_freep(&s->avmv);
616
617     if (res < 0)
618         return res;
619
620     *got_frame = 1;
621
622     bytes_read= c->bytestream - c->bytestream_start;
623     if(bytes_read ==0) av_log(s->avctx, AV_LOG_ERROR, "error at end of frame\n"); //FIXME
624
625     return bytes_read;
626 }
627
628 static av_cold int decode_end(AVCodecContext *avctx)
629 {
630     SnowContext *s = avctx->priv_data;
631
632     ff_slice_buffer_destroy(&s->sb);
633
634     ff_snow_common_end(s);
635
636     return 0;
637 }
638
639 AVCodec ff_snow_decoder = {
640     .name           = "snow",
641     .long_name      = NULL_IF_CONFIG_SMALL("Snow"),
642     .type           = AVMEDIA_TYPE_VIDEO,
643     .id             = AV_CODEC_ID_SNOW,
644     .priv_data_size = sizeof(SnowContext),
645     .init           = decode_init,
646     .close          = decode_end,
647     .decode         = decode_frame,
648     .capabilities   = AV_CODEC_CAP_DR1 /*| AV_CODEC_CAP_DRAW_HORIZ_BAND*/,
649     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
650                       FF_CODEC_CAP_INIT_CLEANUP,
651 };