xref: /third_party/ffmpeg/libavcodec/snowdec.c (revision cabdff1a)
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 "codec_internal.h"
26#include "snow_dwt.h"
27#include "snow.h"
28
29#include "rangecoder.h"
30#include "mathops.h"
31
32static av_always_inline void predict_slice_buffered(SnowContext *s, slice_buffer * sb, IDWTELEM * old_buffer, int plane_index, int add, int mb_y){
33    Plane *p= &s->plane[plane_index];
34    const int mb_w= s->b_width  << s->block_max_depth;
35    const int mb_h= s->b_height << s->block_max_depth;
36    int x, y, mb_x;
37    int block_size = MB_SIZE >> s->block_max_depth;
38    int block_w    = plane_index ? block_size>>s->chroma_h_shift : block_size;
39    int block_h    = plane_index ? block_size>>s->chroma_v_shift : block_size;
40    const uint8_t *obmc  = plane_index ? ff_obmc_tab[s->block_max_depth+s->chroma_h_shift] : ff_obmc_tab[s->block_max_depth];
41    int obmc_stride= plane_index ? (2*block_size)>>s->chroma_h_shift : 2*block_size;
42    int ref_stride= s->current_picture->linesize[plane_index];
43    uint8_t *dst8= s->current_picture->data[plane_index];
44    int w= p->width;
45    int h= p->height;
46
47    if(s->keyframe || (s->avctx->debug&512)){
48        if(mb_y==mb_h)
49            return;
50
51        if(add){
52            for(y=block_h*mb_y; y<FFMIN(h,block_h*(mb_y+1)); y++){
53//                DWTELEM * line = slice_buffer_get_line(sb, y);
54                IDWTELEM * line = sb->line[y];
55                for(x=0; x<w; x++){
56//                    int v= buf[x + y*w] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
57                    int v= line[x] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
58                    v >>= FRAC_BITS;
59                    if(v&(~255)) v= ~(v>>31);
60                    dst8[x + y*ref_stride]= v;
61                }
62            }
63        }else{
64            for(y=block_h*mb_y; y<FFMIN(h,block_h*(mb_y+1)); y++){
65//                DWTELEM * line = slice_buffer_get_line(sb, y);
66                IDWTELEM * line = sb->line[y];
67                for(x=0; x<w; x++){
68                    line[x] -= 128 << FRAC_BITS;
69//                    buf[x + y*w]-= 128<<FRAC_BITS;
70                }
71            }
72        }
73
74        return;
75    }
76
77    for(mb_x=0; mb_x<=mb_w; mb_x++){
78        add_yblock(s, 1, sb, old_buffer, dst8, obmc,
79                   block_w*mb_x - block_w/2,
80                   block_h*mb_y - block_h/2,
81                   block_w, block_h,
82                   w, h,
83                   w, ref_stride, obmc_stride,
84                   mb_x - 1, mb_y - 1,
85                   add, 0, plane_index);
86    }
87
88    if(s->avmv && mb_y < mb_h && plane_index == 0)
89        for(mb_x=0; mb_x<mb_w; mb_x++){
90            AVMotionVector *avmv = s->avmv + s->avmv_index;
91            const int b_width = s->b_width  << s->block_max_depth;
92            const int b_stride= b_width;
93            BlockNode *bn= &s->block[mb_x + mb_y*b_stride];
94
95            if (bn->type)
96                continue;
97
98            s->avmv_index++;
99
100            avmv->w = block_w;
101            avmv->h = block_h;
102            avmv->dst_x = block_w*mb_x - block_w/2;
103            avmv->dst_y = block_h*mb_y - block_h/2;
104            avmv->motion_scale = 8;
105            avmv->motion_x = bn->mx * s->mv_scale;
106            avmv->motion_y = bn->my * s->mv_scale;
107            avmv->src_x = avmv->dst_x + avmv->motion_x / 8;
108            avmv->src_y = avmv->dst_y + avmv->motion_y / 8;
109            avmv->source= -1 - bn->ref;
110            avmv->flags = 0;
111        }
112}
113
114static inline void decode_subband_slice_buffered(SnowContext *s, SubBand *b, slice_buffer * sb, int start_y, int h, int save_state[1]){
115    const int w= b->width;
116    int y;
117    const int qlog= av_clip(s->qlog + (int64_t)b->qlog, 0, QROOT*16);
118    int qmul= ff_qexp[qlog&(QROOT-1)]<<(qlog>>QSHIFT);
119    int qadd= (s->qbias*qmul)>>QBIAS_SHIFT;
120    int new_index = 0;
121
122    if(b->ibuf == s->spatial_idwt_buffer || s->qlog == LOSSLESS_QLOG){
123        qadd= 0;
124        qmul= 1<<QEXPSHIFT;
125    }
126
127    /* If we are on the second or later slice, restore our index. */
128    if (start_y != 0)
129        new_index = save_state[0];
130
131
132    for(y=start_y; y<h; y++){
133        int x = 0;
134        int v;
135        IDWTELEM * line = slice_buffer_get_line(sb, y * b->stride_line + b->buf_y_offset) + b->buf_x_offset;
136        memset(line, 0, b->width*sizeof(IDWTELEM));
137        v = b->x_coeff[new_index].coeff;
138        x = b->x_coeff[new_index++].x;
139        while(x < w){
140            register int t= (int)( (v>>1)*(unsigned)qmul + qadd)>>QEXPSHIFT;
141            register int u= -(v&1);
142            line[x] = (t^u) - u;
143
144            v = b->x_coeff[new_index].coeff;
145            x = b->x_coeff[new_index++].x;
146        }
147    }
148
149    /* Save our variables for the next slice. */
150    save_state[0] = new_index;
151
152    return;
153}
154
155static int decode_q_branch(SnowContext *s, int level, int x, int y){
156    const int w= s->b_width << s->block_max_depth;
157    const int rem_depth= s->block_max_depth - level;
158    const int index= (x + y*w) << rem_depth;
159    int trx= (x+1)<<rem_depth;
160    const BlockNode *left  = x ? &s->block[index-1] : &null_block;
161    const BlockNode *top   = y ? &s->block[index-w] : &null_block;
162    const BlockNode *tl    = y && x ? &s->block[index-w-1] : left;
163    const BlockNode *tr    = y && trx<w && ((x&1)==0 || level==0) ? &s->block[index-w+(1<<rem_depth)] : tl; //FIXME use lt
164    int s_context= 2*left->level + 2*top->level + tl->level + tr->level;
165    int res;
166
167    if(s->keyframe){
168        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);
169        return 0;
170    }
171
172    if(level==s->block_max_depth || get_rac(&s->c, &s->block_state[4 + s_context])){
173        int type, mx, my;
174        int l = left->color[0];
175        int cb= left->color[1];
176        int cr= left->color[2];
177        unsigned ref = 0;
178        int ref_context= av_log2(2*left->ref) + av_log2(2*top->ref);
179        int mx_context= av_log2(2*FFABS(left->mx - top->mx)) + 0*av_log2(2*FFABS(tr->mx - top->mx));
180        int my_context= av_log2(2*FFABS(left->my - top->my)) + 0*av_log2(2*FFABS(tr->my - top->my));
181
182        type= get_rac(&s->c, &s->block_state[1 + left->type + top->type]) ? BLOCK_INTRA : 0;
183        if(type){
184            int ld, cbd, crd;
185            pred_mv(s, &mx, &my, 0, left, top, tr);
186            ld = get_symbol(&s->c, &s->block_state[32], 1);
187            if (ld < -255 || ld > 255) {
188                return AVERROR_INVALIDDATA;
189            }
190            l += ld;
191            if (s->nb_planes > 2) {
192                cbd = get_symbol(&s->c, &s->block_state[64], 1);
193                crd = get_symbol(&s->c, &s->block_state[96], 1);
194                if (cbd < -255 || cbd > 255 || crd < -255 || crd > 255) {
195                    return AVERROR_INVALIDDATA;
196                }
197                cb += cbd;
198                cr += crd;
199            }
200        }else{
201            if(s->ref_frames > 1)
202                ref= get_symbol(&s->c, &s->block_state[128 + 1024 + 32*ref_context], 0);
203            if (ref >= s->ref_frames) {
204                av_log(s->avctx, AV_LOG_ERROR, "Invalid ref\n");
205                return AVERROR_INVALIDDATA;
206            }
207            pred_mv(s, &mx, &my, ref, left, top, tr);
208            mx+= (unsigned)get_symbol(&s->c, &s->block_state[128 + 32*(mx_context + 16*!!ref)], 1);
209            my+= (unsigned)get_symbol(&s->c, &s->block_state[128 + 32*(my_context + 16*!!ref)], 1);
210        }
211        set_blocks(s, level, x, y, l, cb, cr, mx, my, ref, type);
212    }else{
213        if ((res = decode_q_branch(s, level+1, 2*x+0, 2*y+0)) < 0 ||
214            (res = decode_q_branch(s, level+1, 2*x+1, 2*y+0)) < 0 ||
215            (res = decode_q_branch(s, level+1, 2*x+0, 2*y+1)) < 0 ||
216            (res = decode_q_branch(s, level+1, 2*x+1, 2*y+1)) < 0)
217            return res;
218    }
219    return 0;
220}
221
222static void dequantize_slice_buffered(SnowContext *s, slice_buffer * sb, SubBand *b, IDWTELEM *src, int stride, int start_y, int end_y){
223    const int w= b->width;
224    const int qlog= av_clip(s->qlog + (int64_t)b->qlog, 0, QROOT*16);
225    const int qmul= ff_qexp[qlog&(QROOT-1)]<<(qlog>>QSHIFT);
226    const int qadd= (s->qbias*qmul)>>QBIAS_SHIFT;
227    int x,y;
228
229    if(s->qlog == LOSSLESS_QLOG) return;
230
231    for(y=start_y; y<end_y; y++){
232//        DWTELEM * line = slice_buffer_get_line_from_address(sb, src + (y * stride));
233        IDWTELEM * line = slice_buffer_get_line(sb, (y * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
234        for(x=0; x<w; x++){
235            int i= line[x];
236            if(i<0){
237                line[x]= -((-i*(unsigned)qmul + qadd)>>(QEXPSHIFT)); //FIXME try different bias
238            }else if(i>0){
239                line[x]=  (( i*(unsigned)qmul + qadd)>>(QEXPSHIFT));
240            }
241        }
242    }
243}
244
245static 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){
246    const int w= b->width;
247    int x,y;
248
249    IDWTELEM * line=0; // silence silly "could be used without having been initialized" warning
250    IDWTELEM * prev;
251
252    if (start_y != 0)
253        line = slice_buffer_get_line(sb, ((start_y - 1) * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
254
255    for(y=start_y; y<end_y; y++){
256        prev = line;
257//        line = slice_buffer_get_line_from_address(sb, src + (y * stride));
258        line = slice_buffer_get_line(sb, (y * b->stride_line) + b->buf_y_offset) + b->buf_x_offset;
259        for(x=0; x<w; x++){
260            if(x){
261                if(use_median){
262                    if(y && x+1<w) line[x] += mid_pred(line[x - 1], prev[x], prev[x + 1]);
263                    else  line[x] += line[x - 1];
264                }else{
265                    if(y) line[x] += mid_pred(line[x - 1], prev[x], line[x - 1] + prev[x] - prev[x - 1]);
266                    else  line[x] += line[x - 1];
267                }
268            }else{
269                if(y) line[x] += prev[x];
270            }
271        }
272    }
273}
274
275static void decode_qlogs(SnowContext *s){
276    int plane_index, level, orientation;
277
278    for(plane_index=0; plane_index < s->nb_planes; plane_index++){
279        for(level=0; level<s->spatial_decomposition_count; level++){
280            for(orientation=level ? 1:0; orientation<4; orientation++){
281                int q;
282                if     (plane_index==2) q= s->plane[1].band[level][orientation].qlog;
283                else if(orientation==2) q= s->plane[plane_index].band[level][1].qlog;
284                else                    q= get_symbol(&s->c, s->header_state, 1);
285                s->plane[plane_index].band[level][orientation].qlog= q;
286            }
287        }
288    }
289}
290
291#define GET_S(dst, check) \
292    tmp= get_symbol(&s->c, s->header_state, 0);\
293    if(!(check)){\
294        av_log(s->avctx, AV_LOG_ERROR, "Error " #dst " is %d\n", tmp);\
295        return AVERROR_INVALIDDATA;\
296    }\
297    dst= tmp;
298
299static int decode_header(SnowContext *s){
300    int plane_index, tmp;
301    uint8_t kstate[32];
302
303    memset(kstate, MID_STATE, sizeof(kstate));
304
305    s->keyframe= get_rac(&s->c, kstate);
306    if(s->keyframe || s->always_reset){
307        ff_snow_reset_contexts(s);
308        s->spatial_decomposition_type=
309        s->qlog=
310        s->qbias=
311        s->mv_scale=
312        s->block_max_depth= 0;
313    }
314    if(s->keyframe){
315        GET_S(s->version, tmp <= 0U)
316        s->always_reset= get_rac(&s->c, s->header_state);
317        s->temporal_decomposition_type= get_symbol(&s->c, s->header_state, 0);
318        s->temporal_decomposition_count= get_symbol(&s->c, s->header_state, 0);
319        GET_S(s->spatial_decomposition_count, 0 < tmp && tmp <= MAX_DECOMPOSITIONS)
320        s->colorspace_type= get_symbol(&s->c, s->header_state, 0);
321        if (s->colorspace_type == 1) {
322            s->avctx->pix_fmt= AV_PIX_FMT_GRAY8;
323            s->nb_planes = 1;
324        } else if(s->colorspace_type == 0) {
325            s->chroma_h_shift= get_symbol(&s->c, s->header_state, 0);
326            s->chroma_v_shift= get_symbol(&s->c, s->header_state, 0);
327
328            if(s->chroma_h_shift == 1 && s->chroma_v_shift==1){
329                s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
330            }else if(s->chroma_h_shift == 0 && s->chroma_v_shift==0){
331                s->avctx->pix_fmt= AV_PIX_FMT_YUV444P;
332            }else if(s->chroma_h_shift == 2 && s->chroma_v_shift==2){
333                s->avctx->pix_fmt= AV_PIX_FMT_YUV410P;
334            } else {
335                av_log(s, AV_LOG_ERROR, "unsupported color subsample mode %d %d\n", s->chroma_h_shift, s->chroma_v_shift);
336                s->chroma_h_shift = s->chroma_v_shift = 1;
337                s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
338                return AVERROR_INVALIDDATA;
339            }
340            s->nb_planes = 3;
341        } else {
342            av_log(s, AV_LOG_ERROR, "unsupported color space\n");
343            s->chroma_h_shift = s->chroma_v_shift = 1;
344            s->avctx->pix_fmt= AV_PIX_FMT_YUV420P;
345            return AVERROR_INVALIDDATA;
346        }
347
348
349        s->spatial_scalability= get_rac(&s->c, s->header_state);
350//        s->rate_scalability= get_rac(&s->c, s->header_state);
351        GET_S(s->max_ref_frames, tmp < (unsigned)MAX_REF_FRAMES)
352        s->max_ref_frames++;
353
354        decode_qlogs(s);
355    }
356
357    if(!s->keyframe){
358        if(get_rac(&s->c, s->header_state)){
359            for(plane_index=0; plane_index<FFMIN(s->nb_planes, 2); plane_index++){
360                int htaps, i, sum=0;
361                Plane *p= &s->plane[plane_index];
362                p->diag_mc= get_rac(&s->c, s->header_state);
363                htaps= get_symbol(&s->c, s->header_state, 0);
364                if((unsigned)htaps >= HTAPS_MAX/2 - 1)
365                    return AVERROR_INVALIDDATA;
366                htaps = htaps*2 + 2;
367                p->htaps= htaps;
368                for(i= htaps/2; i; i--){
369                    unsigned hcoeff = get_symbol(&s->c, s->header_state, 0);
370                    if (hcoeff > 127)
371                        return AVERROR_INVALIDDATA;
372                    p->hcoeff[i]= hcoeff * (1-2*(i&1));
373                    sum += p->hcoeff[i];
374                }
375                p->hcoeff[0]= 32-sum;
376            }
377            s->plane[2].diag_mc= s->plane[1].diag_mc;
378            s->plane[2].htaps  = s->plane[1].htaps;
379            memcpy(s->plane[2].hcoeff, s->plane[1].hcoeff, sizeof(s->plane[1].hcoeff));
380        }
381        if(get_rac(&s->c, s->header_state)){
382            GET_S(s->spatial_decomposition_count, 0 < tmp && tmp <= MAX_DECOMPOSITIONS)
383            decode_qlogs(s);
384        }
385    }
386
387    s->spatial_decomposition_type+= (unsigned)get_symbol(&s->c, s->header_state, 1);
388    if(s->spatial_decomposition_type > 1U){
389        av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_type %d not supported\n", s->spatial_decomposition_type);
390        return AVERROR_INVALIDDATA;
391    }
392    if(FFMIN(s->avctx-> width>>s->chroma_h_shift,
393             s->avctx->height>>s->chroma_v_shift) >> (s->spatial_decomposition_count-1) <= 1){
394        av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_count %d too large for size\n", s->spatial_decomposition_count);
395        return AVERROR_INVALIDDATA;
396    }
397    if (s->avctx->width > 65536-4) {
398        av_log(s->avctx, AV_LOG_ERROR, "Width %d is too large\n", s->avctx->width);
399        return AVERROR_INVALIDDATA;
400    }
401
402
403    s->qlog           += (unsigned)get_symbol(&s->c, s->header_state, 1);
404    s->mv_scale       += (unsigned)get_symbol(&s->c, s->header_state, 1);
405    s->qbias          += (unsigned)get_symbol(&s->c, s->header_state, 1);
406    s->block_max_depth+= (unsigned)get_symbol(&s->c, s->header_state, 1);
407    if(s->block_max_depth > 1 || s->block_max_depth < 0 || s->mv_scale > 256U){
408        av_log(s->avctx, AV_LOG_ERROR, "block_max_depth= %d is too large\n", s->block_max_depth);
409        s->block_max_depth= 0;
410        s->mv_scale = 0;
411        return AVERROR_INVALIDDATA;
412    }
413    if (FFABS(s->qbias) > 127) {
414        av_log(s->avctx, AV_LOG_ERROR, "qbias %d is too large\n", s->qbias);
415        s->qbias = 0;
416        return AVERROR_INVALIDDATA;
417    }
418
419    return 0;
420}
421
422static int decode_blocks(SnowContext *s){
423    int x, y;
424    int w= s->b_width;
425    int h= s->b_height;
426    int res;
427
428    for(y=0; y<h; y++){
429        for(x=0; x<w; x++){
430            if (s->c.bytestream >= s->c.bytestream_end)
431                return AVERROR_INVALIDDATA;
432            if ((res = decode_q_branch(s, 0, x, y)) < 0)
433                return res;
434        }
435    }
436    return 0;
437}
438
439static int decode_frame(AVCodecContext *avctx, AVFrame *picture,
440                        int *got_frame, AVPacket *avpkt)
441{
442    const uint8_t *buf = avpkt->data;
443    int buf_size = avpkt->size;
444    SnowContext *s = avctx->priv_data;
445    RangeCoder * const c= &s->c;
446    int bytes_read;
447    int level, orientation, plane_index;
448    int res;
449
450    ff_init_range_decoder(c, buf, buf_size);
451    ff_build_rac_states(c, 0.05*(1LL<<32), 256-8);
452
453    s->current_picture->pict_type= AV_PICTURE_TYPE_I; //FIXME I vs. P
454    if ((res = decode_header(s)) < 0)
455        return res;
456    if ((res=ff_snow_common_init_after_header(avctx)) < 0)
457        return res;
458
459    // realloc slice buffer for the case that spatial_decomposition_count changed
460    ff_slice_buffer_destroy(&s->sb);
461    if ((res = ff_slice_buffer_init(&s->sb, s->plane[0].height,
462                                    (MB_SIZE >> s->block_max_depth) +
463                                    s->spatial_decomposition_count * 11 + 1,
464                                    s->plane[0].width,
465                                    s->spatial_idwt_buffer)) < 0)
466        return res;
467
468    for(plane_index=0; plane_index < s->nb_planes; plane_index++){
469        Plane *p= &s->plane[plane_index];
470        p->fast_mc= p->diag_mc && p->htaps==6 && p->hcoeff[0]==40
471                                              && p->hcoeff[1]==-10
472                                              && p->hcoeff[2]==2;
473    }
474
475    ff_snow_alloc_blocks(s);
476
477    if((res = ff_snow_frame_start(s)) < 0)
478        return res;
479
480    s->current_picture->pict_type = s->keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
481
482    //keyframe flag duplication mess FIXME
483    if(avctx->debug&FF_DEBUG_PICT_INFO)
484        av_log(avctx, AV_LOG_ERROR,
485               "keyframe:%d qlog:%d qbias: %d mvscale: %d "
486               "decomposition_type:%d decomposition_count:%d\n",
487               s->keyframe, s->qlog, s->qbias, s->mv_scale,
488               s->spatial_decomposition_type,
489               s->spatial_decomposition_count
490              );
491
492    if (s->avctx->export_side_data & AV_CODEC_EXPORT_DATA_MVS) {
493        size_t size;
494        res = av_size_mult(s->b_width * s->b_height, sizeof(AVMotionVector) << (s->block_max_depth*2), &size);
495        if (res)
496            return res;
497        av_fast_malloc(&s->avmv, &s->avmv_size, size);
498        if (!s->avmv)
499            return AVERROR(ENOMEM);
500    } else {
501        s->avmv_size = 0;
502        av_freep(&s->avmv);
503    }
504    s->avmv_index = 0;
505
506    if ((res = decode_blocks(s)) < 0)
507        return res;
508
509    for(plane_index=0; plane_index < s->nb_planes; plane_index++){
510        Plane *p= &s->plane[plane_index];
511        int w= p->width;
512        int h= p->height;
513        int x, y;
514        int decode_state[MAX_DECOMPOSITIONS][4][1]; /* Stored state info for unpack_coeffs. 1 variable per instance. */
515
516        if(s->avctx->debug&2048){
517            memset(s->spatial_dwt_buffer, 0, sizeof(DWTELEM)*w*h);
518            predict_plane(s, s->spatial_idwt_buffer, plane_index, 1);
519
520            for(y=0; y<h; y++){
521                for(x=0; x<w; x++){
522                    int v= s->current_picture->data[plane_index][y*s->current_picture->linesize[plane_index] + x];
523                    s->mconly_picture->data[plane_index][y*s->mconly_picture->linesize[plane_index] + x]= v;
524                }
525            }
526        }
527
528        for(level=0; level<s->spatial_decomposition_count; level++){
529            for(orientation=level ? 1 : 0; orientation<4; orientation++){
530                SubBand *b= &p->band[level][orientation];
531                unpack_coeffs(s, b, b->parent, orientation);
532            }
533        }
534
535        {
536        const int mb_h= s->b_height << s->block_max_depth;
537        const int block_size = MB_SIZE >> s->block_max_depth;
538        const int block_h    = plane_index ? block_size>>s->chroma_v_shift : block_size;
539        int mb_y;
540        DWTCompose cs[MAX_DECOMPOSITIONS];
541        int yd=0, yq=0;
542        int y;
543        int end_y;
544
545        ff_spatial_idwt_buffered_init(cs, &s->sb, w, h, 1, s->spatial_decomposition_type, s->spatial_decomposition_count);
546        for(mb_y=0; mb_y<=mb_h; mb_y++){
547
548            int slice_starty = block_h*mb_y;
549            int slice_h = block_h*(mb_y+1);
550
551            if (!(s->keyframe || s->avctx->debug&512)){
552                slice_starty = FFMAX(0, slice_starty - (block_h >> 1));
553                slice_h -= (block_h >> 1);
554            }
555
556            for(level=0; level<s->spatial_decomposition_count; level++){
557                for(orientation=level ? 1 : 0; orientation<4; orientation++){
558                    SubBand *b= &p->band[level][orientation];
559                    int start_y;
560                    int end_y;
561                    int our_mb_start = mb_y;
562                    int our_mb_end = (mb_y + 1);
563                    const int extra= 3;
564                    start_y = (mb_y ? ((block_h * our_mb_start) >> (s->spatial_decomposition_count - level)) + s->spatial_decomposition_count - level + extra: 0);
565                    end_y = (((block_h * our_mb_end) >> (s->spatial_decomposition_count - level)) + s->spatial_decomposition_count - level + extra);
566                    if (!(s->keyframe || s->avctx->debug&512)){
567                        start_y = FFMAX(0, start_y - (block_h >> (1+s->spatial_decomposition_count - level)));
568                        end_y = FFMAX(0, end_y - (block_h >> (1+s->spatial_decomposition_count - level)));
569                    }
570                    start_y = FFMIN(b->height, start_y);
571                    end_y = FFMIN(b->height, end_y);
572
573                    if (start_y != end_y){
574                        if (orientation == 0){
575                            SubBand * correlate_band = &p->band[0][0];
576                            int correlate_end_y = FFMIN(b->height, end_y + 1);
577                            int correlate_start_y = FFMIN(b->height, (start_y ? start_y + 1 : 0));
578                            decode_subband_slice_buffered(s, correlate_band, &s->sb, correlate_start_y, correlate_end_y, decode_state[0][0]);
579                            correlate_slice_buffered(s, &s->sb, correlate_band, correlate_band->ibuf, correlate_band->stride, 1, 0, correlate_start_y, correlate_end_y);
580                            dequantize_slice_buffered(s, &s->sb, correlate_band, correlate_band->ibuf, correlate_band->stride, start_y, end_y);
581                        }
582                        else
583                            decode_subband_slice_buffered(s, b, &s->sb, start_y, end_y, decode_state[level][orientation]);
584                    }
585                }
586            }
587
588            for(; yd<slice_h; yd+=4){
589                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);
590            }
591
592            if(s->qlog == LOSSLESS_QLOG){
593                for(; yq<slice_h && yq<h; yq++){
594                    IDWTELEM * line = slice_buffer_get_line(&s->sb, yq);
595                    for(x=0; x<w; x++){
596                        line[x] *= 1<<FRAC_BITS;
597                    }
598                }
599            }
600
601            predict_slice_buffered(s, &s->sb, s->spatial_idwt_buffer, plane_index, 1, mb_y);
602
603            y = FFMIN(p->height, slice_starty);
604            end_y = FFMIN(p->height, slice_h);
605            while(y < end_y)
606                ff_slice_buffer_release(&s->sb, y++);
607        }
608
609        ff_slice_buffer_flush(&s->sb);
610        }
611
612    }
613
614    emms_c();
615
616    ff_snow_release_buffer(avctx);
617
618    if(!(s->avctx->debug&2048))
619        res = av_frame_ref(picture, s->current_picture);
620    else
621        res = av_frame_ref(picture, s->mconly_picture);
622    if (res >= 0 && s->avmv_index) {
623        AVFrameSideData *sd;
624
625        sd = av_frame_new_side_data(picture, AV_FRAME_DATA_MOTION_VECTORS, s->avmv_index * sizeof(AVMotionVector));
626        if (!sd)
627            return AVERROR(ENOMEM);
628        memcpy(sd->data, s->avmv, s->avmv_index * sizeof(AVMotionVector));
629    }
630
631    if (res < 0)
632        return res;
633
634    *got_frame = 1;
635
636    bytes_read= c->bytestream - c->bytestream_start;
637    if(bytes_read ==0) av_log(s->avctx, AV_LOG_ERROR, "error at end of frame\n"); //FIXME
638
639    return bytes_read;
640}
641
642static av_cold int decode_end(AVCodecContext *avctx)
643{
644    SnowContext *s = avctx->priv_data;
645
646    ff_slice_buffer_destroy(&s->sb);
647
648    ff_snow_common_end(s);
649
650    s->avmv_size = 0;
651    av_freep(&s->avmv);
652
653    return 0;
654}
655
656const FFCodec ff_snow_decoder = {
657    .p.name         = "snow",
658    .p.long_name    = NULL_IF_CONFIG_SMALL("Snow"),
659    .p.type         = AVMEDIA_TYPE_VIDEO,
660    .p.id           = AV_CODEC_ID_SNOW,
661    .priv_data_size = sizeof(SnowContext),
662    .init           = ff_snow_common_init,
663    .close          = decode_end,
664    FF_CODEC_DECODE_CB(decode_frame),
665    .p.capabilities = AV_CODEC_CAP_DR1 /*| AV_CODEC_CAP_DRAW_HORIZ_BAND*/,
666    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
667                      FF_CODEC_CAP_INIT_CLEANUP,
668};
669