FFmpeg: libavcodec/snow.h Source File

00001 /*
00002  * Copyright (C) 2004 Michael Niedermayer <michaelni@gmx.at>
00003  * Copyright (C) 2006 Robert Edele <yartrebo@earthlink.net>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #ifndef AVCODEC_SNOW_H
00023 #define AVCODEC_SNOW_H
00024 
00025 #include "dsputil.h"
00026 #include "dwt.h"
00027 
00028 #include "rangecoder.h"
00029 #include "mathops.h"
00030 #include "mpegvideo.h"
00031 
00032 #define MID_STATE 128
00033 
00034 #define MAX_PLANES 4
00035 #define QSHIFT 5
00036 #define QROOT (1<<QSHIFT)
00037 #define LOSSLESS_QLOG -128
00038 #define FRAC_BITS 4
00039 #define MAX_REF_FRAMES 8
00040 
00041 #define LOG2_OBMC_MAX 8
00042 #define OBMC_MAX (1<<(LOG2_OBMC_MAX))
00043 typedef struct BlockNode{
00044     int16_t mx;
00045     int16_t my;
00046     uint8_t ref;
00047     uint8_t color[3];
00048     uint8_t type;
00049 //#define TYPE_SPLIT    1
00050 #define BLOCK_INTRA   1
00051 #define BLOCK_OPT     2
00052 //#define TYPE_NOCOLOR  4
00053     uint8_t level; //FIXME merge into type?
00054 }BlockNode;
00055 
00056 static const BlockNode null_block= { //FIXME add border maybe
00057     .color= {128,128,128},
00058     .mx= 0,
00059     .my= 0,
00060     .ref= 0,
00061     .type= 0,
00062     .level= 0,
00063 };
00064 
00065 #define LOG2_MB_SIZE 4
00066 #define MB_SIZE (1<<LOG2_MB_SIZE)
00067 #define ENCODER_EXTRA_BITS 4
00068 #define HTAPS_MAX 8
00069 
00070 typedef struct x_and_coeff{
00071     int16_t x;
00072     uint16_t coeff;
00073 } x_and_coeff;
00074 
00075 typedef struct SubBand{
00076     int level;
00077     int stride;
00078     int width;
00079     int height;
00080     int qlog;        
00081     DWTELEM *buf;
00082     IDWTELEM *ibuf;
00083     int buf_x_offset;
00084     int buf_y_offset;
00085     int stride_line; 
00086     x_and_coeff * x_coeff;
00087     struct SubBand *parent;
00088     uint8_t state[/*7*2*/ 7 + 512][32];
00089 }SubBand;
00090 
00091 typedef struct Plane{
00092     int width;
00093     int height;
00094     SubBand band[MAX_DECOMPOSITIONS][4];
00095 
00096     int htaps;
00097     int8_t hcoeff[HTAPS_MAX/2];
00098     int diag_mc;
00099     int fast_mc;
00100 
00101     int last_htaps;
00102     int8_t last_hcoeff[HTAPS_MAX/2];
00103     int last_diag_mc;
00104 }Plane;
00105 
00106 typedef struct SnowContext{
00107     AVClass *class;
00108     AVCodecContext *avctx;
00109     RangeCoder c;
00110     DSPContext dsp;
00111     DWTContext dwt;
00112     AVFrame new_picture;
00113     AVFrame input_picture;              
00114     AVFrame current_picture;
00115     AVFrame last_picture[MAX_REF_FRAMES];
00116     uint8_t *halfpel_plane[MAX_REF_FRAMES][4][4];
00117     AVFrame mconly_picture;
00118 //     uint8_t q_context[16];
00119     uint8_t header_state[32];
00120     uint8_t block_state[128 + 32*128];
00121     int keyframe;
00122     int always_reset;
00123     int version;
00124     int spatial_decomposition_type;
00125     int last_spatial_decomposition_type;
00126     int temporal_decomposition_type;
00127     int spatial_decomposition_count;
00128     int last_spatial_decomposition_count;
00129     int temporal_decomposition_count;
00130     int max_ref_frames;
00131     int ref_frames;
00132     int16_t (*ref_mvs[MAX_REF_FRAMES])[2];
00133     uint32_t *ref_scores[MAX_REF_FRAMES];
00134     DWTELEM *spatial_dwt_buffer;
00135     IDWTELEM *spatial_idwt_buffer;
00136     int colorspace_type;
00137     int chroma_h_shift;
00138     int chroma_v_shift;
00139     int spatial_scalability;
00140     int qlog;
00141     int last_qlog;
00142     int lambda;
00143     int lambda2;
00144     int pass1_rc;
00145     int mv_scale;
00146     int last_mv_scale;
00147     int qbias;
00148     int last_qbias;
00149 #define QBIAS_SHIFT 3
00150     int b_width;
00151     int b_height;
00152     int block_max_depth;
00153     int last_block_max_depth;
00154     Plane plane[MAX_PLANES];
00155     BlockNode *block;
00156 #define ME_CACHE_SIZE 1024
00157     unsigned me_cache[ME_CACHE_SIZE];
00158     unsigned me_cache_generation;
00159     slice_buffer sb;
00160     int memc_only;
00161     int no_bitstream;
00162 
00163     MpegEncContext m; // needed for motion estimation, should not be used for anything else, the idea is to eventually make the motion estimation independent of MpegEncContext, so this will be removed then (FIXME/XXX)
00164 
00165     uint8_t *scratchbuf;
00166     int *runs;
00167 }SnowContext;
00168 
00169 /* Tables */
00170 extern const uint8_t * const ff_obmc_tab[4];
00171 extern uint8_t ff_qexp[QROOT];
00172 extern int ff_scale_mv_ref[MAX_REF_FRAMES][MAX_REF_FRAMES];
00173 
00174 /* C bits used by mmx/sse2/altivec */
00175 
00176 static av_always_inline void snow_interleave_line_header(int * i, int width, IDWTELEM * low, IDWTELEM * high){
00177     (*i) = (width) - 2;
00178 
00179     if (width & 1){
00180         low[(*i)+1] = low[((*i)+1)>>1];
00181         (*i)--;
00182     }
00183 }
00184 
00185 static av_always_inline void snow_interleave_line_footer(int * i, IDWTELEM * low, IDWTELEM * high){
00186     for (; (*i)>=0; (*i)-=2){
00187         low[(*i)+1] = high[(*i)>>1];
00188         low[*i] = low[(*i)>>1];
00189     }
00190 }
00191 
00192 static av_always_inline void snow_horizontal_compose_lift_lead_out(int i, IDWTELEM * dst, IDWTELEM * src, IDWTELEM * ref, int width, int w, int lift_high, int mul, int add, int shift){
00193     for(; i<w; i++){
00194         dst[i] = src[i] - ((mul * (ref[i] + ref[i + 1]) + add) >> shift);
00195     }
00196 
00197     if((width^lift_high)&1){
00198         dst[w] = src[w] - ((mul * 2 * ref[w] + add) >> shift);
00199     }
00200 }
00201 
00202 static av_always_inline void snow_horizontal_compose_liftS_lead_out(int i, IDWTELEM * dst, IDWTELEM * src, IDWTELEM * ref, int width, int w){
00203         for(; i<w; i++){
00204             dst[i] = src[i] + ((ref[i] + ref[(i+1)]+W_BO + 4 * src[i]) >> W_BS);
00205         }
00206 
00207         if(width&1){
00208             dst[w] = src[w] + ((2 * ref[w] + W_BO + 4 * src[w]) >> W_BS);
00209         }
00210 }
00211 
00212 /* common code */
00213 
00214 int ff_snow_common_init(AVCodecContext *avctx);
00215 int ff_snow_common_init_after_header(AVCodecContext *avctx);
00216 void ff_snow_common_end(SnowContext *s);
00217 void ff_snow_release_buffer(AVCodecContext *avctx);
00218 void ff_snow_reset_contexts(SnowContext *s);
00219 int ff_snow_alloc_blocks(SnowContext *s);
00220 int ff_snow_frame_start(SnowContext *s);
00221 void ff_snow_pred_block(SnowContext *s, uint8_t *dst, uint8_t *tmp, int stride,
00222                      int sx, int sy, int b_w, int b_h, BlockNode *block,
00223                      int plane_index, int w, int h);
00224 /* common inline functions */
00225 //XXX doublecheck all of them should stay inlined
00226 
00227 static inline void snow_set_blocks(SnowContext *s, int level, int x, int y, int l, int cb, int cr, int mx, int my, int ref, int type){
00228     const int w= s->b_width << s->block_max_depth;
00229     const int rem_depth= s->block_max_depth - level;
00230     const int index= (x + y*w) << rem_depth;
00231     const int block_w= 1<<rem_depth;
00232     BlockNode block;
00233     int i,j;
00234 
00235     block.color[0]= l;
00236     block.color[1]= cb;
00237     block.color[2]= cr;
00238     block.mx= mx;
00239     block.my= my;
00240     block.ref= ref;
00241     block.type= type;
00242     block.level= level;
00243 
00244     for(j=0; j<block_w; j++){
00245         for(i=0; i<block_w; i++){
00246             s->block[index + i + j*w]= block;
00247         }
00248     }
00249 }
00250 
00251 static inline void pred_mv(SnowContext *s, int *mx, int *my, int ref,
00252                            const BlockNode *left, const BlockNode *top, const BlockNode *tr){
00253     if(s->ref_frames == 1){
00254         *mx = mid_pred(left->mx, top->mx, tr->mx);
00255         *my = mid_pred(left->my, top->my, tr->my);
00256     }else{
00257         const int *scale = ff_scale_mv_ref[ref];
00258         *mx = mid_pred((left->mx * scale[left->ref] + 128) >>8,
00259                        (top ->mx * scale[top ->ref] + 128) >>8,
00260                        (tr  ->mx * scale[tr  ->ref] + 128) >>8);
00261         *my = mid_pred((left->my * scale[left->ref] + 128) >>8,
00262                        (top ->my * scale[top ->ref] + 128) >>8,
00263                        (tr  ->my * scale[tr  ->ref] + 128) >>8);
00264     }
00265 }
00266 
00267 static av_always_inline int same_block(BlockNode *a, BlockNode *b){
00268     if((a->type&BLOCK_INTRA) && (b->type&BLOCK_INTRA)){
00269         return !((a->color[0] - b->color[0]) | (a->color[1] - b->color[1]) | (a->color[2] - b->color[2]));
00270     }else{
00271         return !((a->mx - b->mx) | (a->my - b->my) | (a->ref - b->ref) | ((a->type ^ b->type)&BLOCK_INTRA));
00272     }
00273 }
00274 
00275 //FIXME name cleanup (b_w, block_w, b_width stuff)
00276 //XXX should we really inline it?
00277 static av_always_inline void add_yblock(SnowContext *s, int sliced, slice_buffer *sb, IDWTELEM *dst, uint8_t *dst8, const uint8_t *obmc, int src_x, int src_y, int b_w, int b_h, int w, int h, int dst_stride, int src_stride, int obmc_stride, int b_x, int b_y, int add, int offset_dst, int plane_index){
00278     const int b_width = s->b_width  << s->block_max_depth;
00279     const int b_height= s->b_height << s->block_max_depth;
00280     const int b_stride= b_width;
00281     BlockNode *lt= &s->block[b_x + b_y*b_stride];
00282     BlockNode *rt= lt+1;
00283     BlockNode *lb= lt+b_stride;
00284     BlockNode *rb= lb+1;
00285     uint8_t *block[4];
00286     int tmp_step= src_stride >= 7*MB_SIZE ? MB_SIZE : MB_SIZE*src_stride;
00287     uint8_t *tmp = s->scratchbuf;
00288     uint8_t *ptmp;
00289     int x,y;
00290 
00291     if(b_x<0){
00292         lt= rt;
00293         lb= rb;
00294     }else if(b_x + 1 >= b_width){
00295         rt= lt;
00296         rb= lb;
00297     }
00298     if(b_y<0){
00299         lt= lb;
00300         rt= rb;
00301     }else if(b_y + 1 >= b_height){
00302         lb= lt;
00303         rb= rt;
00304     }
00305 
00306     if(src_x<0){ //FIXME merge with prev & always round internal width up to *16
00307         obmc -= src_x;
00308         b_w += src_x;
00309         if(!sliced && !offset_dst)
00310             dst -= src_x;
00311         src_x=0;
00312     }else if(src_x + b_w > w){
00313         b_w = w - src_x;
00314     }
00315     if(src_y<0){
00316         obmc -= src_y*obmc_stride;
00317         b_h += src_y;
00318         if(!sliced && !offset_dst)
00319             dst -= src_y*dst_stride;
00320         src_y=0;
00321     }else if(src_y + b_h> h){
00322         b_h = h - src_y;
00323     }
00324 
00325     if(b_w<=0 || b_h<=0) return;
00326 
00327     assert(src_stride > 2*MB_SIZE + 5);
00328 
00329     if(!sliced && offset_dst)
00330         dst += src_x + src_y*dst_stride;
00331     dst8+= src_x + src_y*src_stride;
00332 //    src += src_x + src_y*src_stride;
00333 
00334     ptmp= tmp + 3*tmp_step;
00335     block[0]= ptmp;
00336     ptmp+=tmp_step;
00337     ff_snow_pred_block(s, block[0], tmp, src_stride, src_x, src_y, b_w, b_h, lt, plane_index, w, h);
00338 
00339     if(same_block(lt, rt)){
00340         block[1]= block[0];
00341     }else{
00342         block[1]= ptmp;
00343         ptmp+=tmp_step;
00344         ff_snow_pred_block(s, block[1], tmp, src_stride, src_x, src_y, b_w, b_h, rt, plane_index, w, h);
00345     }
00346 
00347     if(same_block(lt, lb)){
00348         block[2]= block[0];
00349     }else if(same_block(rt, lb)){
00350         block[2]= block[1];
00351     }else{
00352         block[2]= ptmp;
00353         ptmp+=tmp_step;
00354         ff_snow_pred_block(s, block[2], tmp, src_stride, src_x, src_y, b_w, b_h, lb, plane_index, w, h);
00355     }
00356 
00357     if(same_block(lt, rb) ){
00358         block[3]= block[0];
00359     }else if(same_block(rt, rb)){
00360         block[3]= block[1];
00361     }else if(same_block(lb, rb)){
00362         block[3]= block[2];
00363     }else{
00364         block[3]= ptmp;
00365         ff_snow_pred_block(s, block[3], tmp, src_stride, src_x, src_y, b_w, b_h, rb, plane_index, w, h);
00366     }
00367     if(sliced){
00368         s->dwt.inner_add_yblock(obmc, obmc_stride, block, b_w, b_h, src_x,src_y, src_stride, sb, add, dst8);
00369     }else{
00370         for(y=0; y<b_h; y++){
00371             //FIXME ugly misuse of obmc_stride
00372             const uint8_t *obmc1= obmc + y*obmc_stride;
00373             const uint8_t *obmc2= obmc1+ (obmc_stride>>1);
00374             const uint8_t *obmc3= obmc1+ obmc_stride*(obmc_stride>>1);
00375             const uint8_t *obmc4= obmc3+ (obmc_stride>>1);
00376             for(x=0; x<b_w; x++){
00377                 int v=   obmc1[x] * block[3][x + y*src_stride]
00378                         +obmc2[x] * block[2][x + y*src_stride]
00379                         +obmc3[x] * block[1][x + y*src_stride]
00380                         +obmc4[x] * block[0][x + y*src_stride];
00381 
00382                 v <<= 8 - LOG2_OBMC_MAX;
00383                 if(FRAC_BITS != 8){
00384                     v >>= 8 - FRAC_BITS;
00385                 }
00386                 if(add){
00387                     v += dst[x + y*dst_stride];
00388                     v = (v + (1<<(FRAC_BITS-1))) >> FRAC_BITS;
00389                     if(v&(~255)) v= ~(v>>31);
00390                     dst8[x + y*src_stride] = v;
00391                 }else{
00392                     dst[x + y*dst_stride] -= v;
00393                 }
00394             }
00395         }
00396     }
00397 }
00398 
00399 static av_always_inline void predict_slice(SnowContext *s, IDWTELEM *buf, int plane_index, int add, int mb_y){
00400     Plane *p= &s->plane[plane_index];
00401     const int mb_w= s->b_width  << s->block_max_depth;
00402     const int mb_h= s->b_height << s->block_max_depth;
00403     int x, y, mb_x;
00404     int block_size = MB_SIZE >> s->block_max_depth;
00405     int block_w    = plane_index ? block_size/2 : block_size;
00406     const uint8_t *obmc  = plane_index ? ff_obmc_tab[s->block_max_depth+1] : ff_obmc_tab[s->block_max_depth];
00407     const int obmc_stride= plane_index ? block_size : 2*block_size;
00408     int ref_stride= s->current_picture.linesize[plane_index];
00409     uint8_t *dst8= s->current_picture.data[plane_index];
00410     int w= p->width;
00411     int h= p->height;
00412 
00413     if(s->keyframe || (s->avctx->debug&512)){
00414         if(mb_y==mb_h)
00415             return;
00416 
00417         if(add){
00418             for(y=block_w*mb_y; y<FFMIN(h,block_w*(mb_y+1)); y++){
00419                 for(x=0; x<w; x++){
00420                     int v= buf[x + y*w] + (128<<FRAC_BITS) + (1<<(FRAC_BITS-1));
00421                     v >>= FRAC_BITS;
00422                     if(v&(~255)) v= ~(v>>31);
00423                     dst8[x + y*ref_stride]= v;
00424                 }
00425             }
00426         }else{
00427             for(y=block_w*mb_y; y<FFMIN(h,block_w*(mb_y+1)); y++){
00428                 for(x=0; x<w; x++){
00429                     buf[x + y*w]-= 128<<FRAC_BITS;
00430                 }
00431             }
00432         }
00433 
00434         return;
00435     }
00436 
00437     for(mb_x=0; mb_x<=mb_w; mb_x++){
00438         add_yblock(s, 0, NULL, buf, dst8, obmc,
00439                    block_w*mb_x - block_w/2,
00440                    block_w*mb_y - block_w/2,
00441                    block_w, block_w,
00442                    w, h,
00443                    w, ref_stride, obmc_stride,
00444                    mb_x - 1, mb_y - 1,
00445                    add, 1, plane_index);
00446     }
00447 }
00448 
00449 static av_always_inline void predict_plane(SnowContext *s, IDWTELEM *buf, int plane_index, int add){
00450     const int mb_h= s->b_height << s->block_max_depth;
00451     int mb_y;
00452     for(mb_y=0; mb_y<=mb_h; mb_y++)
00453         predict_slice(s, buf, plane_index, add, mb_y);
00454 }
00455 
00456 static inline void set_blocks(SnowContext *s, int level, int x, int y, int l, int cb, int cr, int mx, int my, int ref, int type){
00457     const int w= s->b_width << s->block_max_depth;
00458     const int rem_depth= s->block_max_depth - level;
00459     const int index= (x + y*w) << rem_depth;
00460     const int block_w= 1<<rem_depth;
00461     BlockNode block;
00462     int i,j;
00463 
00464     block.color[0]= l;
00465     block.color[1]= cb;
00466     block.color[2]= cr;
00467     block.mx= mx;
00468     block.my= my;
00469     block.ref= ref;
00470     block.type= type;
00471     block.level= level;
00472 
00473     for(j=0; j<block_w; j++){
00474         for(i=0; i<block_w; i++){
00475             s->block[index + i + j*w]= block;
00476         }
00477     }
00478 }
00479 
00480 static inline void init_ref(MotionEstContext *c, uint8_t *src[3], uint8_t *ref[3], uint8_t *ref2[3], int x, int y, int ref_index){
00481     const int offset[3]= {
00482           y*c->  stride + x,
00483         ((y*c->uvstride + x)>>1),
00484         ((y*c->uvstride + x)>>1),
00485     };
00486     int i;
00487     for(i=0; i<3; i++){
00488         c->src[0][i]= src [i];
00489         c->ref[0][i]= ref [i] + offset[i];
00490     }
00491     assert(!ref_index);
00492 }
00493 
00494 
00495 /* bitstream functions */
00496 
00497 extern const int8_t ff_quant3bA[256];
00498 
00499 #define QEXPSHIFT (7-FRAC_BITS+8) //FIXME try to change this to 0
00500 
00501 static inline void put_symbol(RangeCoder *c, uint8_t *state, int v, int is_signed){
00502     int i;
00503 
00504     if(v){
00505         const int a= FFABS(v);
00506         const int e= av_log2(a);
00507         const int el= FFMIN(e, 10);
00508         put_rac(c, state+0, 0);
00509 
00510         for(i=0; i<el; i++){
00511             put_rac(c, state+1+i, 1);  //1..10
00512         }
00513         for(; i<e; i++){
00514             put_rac(c, state+1+9, 1);  //1..10
00515         }
00516         put_rac(c, state+1+FFMIN(i,9), 0);
00517 
00518         for(i=e-1; i>=el; i--){
00519             put_rac(c, state+22+9, (a>>i)&1); //22..31
00520         }
00521         for(; i>=0; i--){
00522             put_rac(c, state+22+i, (a>>i)&1); //22..31
00523         }
00524 
00525         if(is_signed)
00526             put_rac(c, state+11 + el, v < 0); //11..21
00527     }else{
00528         put_rac(c, state+0, 1);
00529     }
00530 }
00531 
00532 static inline int get_symbol(RangeCoder *c, uint8_t *state, int is_signed){
00533     if(get_rac(c, state+0))
00534         return 0;
00535     else{
00536         int i, e, a;
00537         e= 0;
00538         while(get_rac(c, state+1 + FFMIN(e,9))){ //1..10
00539             e++;
00540         }
00541 
00542         a= 1;
00543         for(i=e-1; i>=0; i--){
00544             a += a + get_rac(c, state+22 + FFMIN(i,9)); //22..31
00545         }
00546 
00547         e= -(is_signed && get_rac(c, state+11 + FFMIN(e,10))); //11..21
00548         return (a^e)-e;
00549     }
00550 }
00551 
00552 static inline void put_symbol2(RangeCoder *c, uint8_t *state, int v, int log2){
00553     int i;
00554     int r= log2>=0 ? 1<<log2 : 1;
00555 
00556     assert(v>=0);
00557     assert(log2>=-4);
00558 
00559     while(v >= r){
00560         put_rac(c, state+4+log2, 1);
00561         v -= r;
00562         log2++;
00563         if(log2>0) r+=r;
00564     }
00565     put_rac(c, state+4+log2, 0);
00566 
00567     for(i=log2-1; i>=0; i--){
00568         put_rac(c, state+31-i, (v>>i)&1);
00569     }
00570 }
00571 
00572 static inline int get_symbol2(RangeCoder *c, uint8_t *state, int log2){
00573     int i;
00574     int r= log2>=0 ? 1<<log2 : 1;
00575     int v=0;
00576 
00577     assert(log2>=-4);
00578 
00579     while(get_rac(c, state+4+log2)){
00580         v+= r;
00581         log2++;
00582         if(log2>0) r+=r;
00583     }
00584 
00585     for(i=log2-1; i>=0; i--){
00586         v+= get_rac(c, state+31-i)<<i;
00587     }
00588 
00589     return v;
00590 }
00591 
00592 static inline void unpack_coeffs(SnowContext *s, SubBand *b, SubBand * parent, int orientation){
00593     const int w= b->width;
00594     const int h= b->height;
00595     int x,y;
00596 
00597     int run, runs;
00598     x_and_coeff *xc= b->x_coeff;
00599     x_and_coeff *prev_xc= NULL;
00600     x_and_coeff *prev2_xc= xc;
00601     x_and_coeff *parent_xc= parent ? parent->x_coeff : NULL;
00602     x_and_coeff *prev_parent_xc= parent_xc;
00603 
00604     runs= get_symbol2(&s->c, b->state[30], 0);
00605     if(runs-- > 0) run= get_symbol2(&s->c, b->state[1], 3);
00606     else           run= INT_MAX;
00607 
00608     for(y=0; y<h; y++){
00609         int v=0;
00610         int lt=0, t=0, rt=0;
00611 
00612         if(y && prev_xc->x == 0){
00613             rt= prev_xc->coeff;
00614         }
00615         for(x=0; x<w; x++){
00616             int p=0;
00617             const int l= v;
00618 
00619             lt= t; t= rt;
00620 
00621             if(y){
00622                 if(prev_xc->x <= x)
00623                     prev_xc++;
00624                 if(prev_xc->x == x + 1)
00625                     rt= prev_xc->coeff;
00626                 else
00627                     rt=0;
00628             }
00629             if(parent_xc){
00630                 if(x>>1 > parent_xc->x){
00631                     parent_xc++;
00632                 }
00633                 if(x>>1 == parent_xc->x){
00634                     p= parent_xc->coeff;
00635                 }
00636             }
00637             if(/*ll|*/l|lt|t|rt|p){
00638                 int context= av_log2(/*FFABS(ll) + */3*(l>>1) + (lt>>1) + (t&~1) + (rt>>1) + (p>>1));
00639 
00640                 v=get_rac(&s->c, &b->state[0][context]);
00641                 if(v){
00642                     v= 2*(get_symbol2(&s->c, b->state[context + 2], context-4) + 1);
00643                     v+=get_rac(&s->c, &b->state[0][16 + 1 + 3 + ff_quant3bA[l&0xFF] + 3*ff_quant3bA[t&0xFF]]);
00644 
00645                     xc->x=x;
00646                     (xc++)->coeff= v;
00647                 }
00648             }else{
00649                 if(!run){
00650                     if(runs-- > 0) run= get_symbol2(&s->c, b->state[1], 3);
00651                     else           run= INT_MAX;
00652                     v= 2*(get_symbol2(&s->c, b->state[0 + 2], 0-4) + 1);
00653                     v+=get_rac(&s->c, &b->state[0][16 + 1 + 3]);
00654 
00655                     xc->x=x;
00656                     (xc++)->coeff= v;
00657                 }else{
00658                     int max_run;
00659                     run--;
00660                     v=0;
00661 
00662                     if(y) max_run= FFMIN(run, prev_xc->x - x - 2);
00663                     else  max_run= FFMIN(run, w-x-1);
00664                     if(parent_xc)
00665                         max_run= FFMIN(max_run, 2*parent_xc->x - x - 1);
00666                     x+= max_run;
00667                     run-= max_run;
00668                 }
00669             }
00670         }
00671         (xc++)->x= w+1; //end marker
00672         prev_xc= prev2_xc;
00673         prev2_xc= xc;
00674 
00675         if(parent_xc){
00676             if(y&1){
00677                 while(parent_xc->x != parent->width+1)
00678                     parent_xc++;
00679                 parent_xc++;
00680                 prev_parent_xc= parent_xc;
00681             }else{
00682                 parent_xc= prev_parent_xc;
00683             }
00684         }
00685     }
00686 
00687     (xc++)->x= w+1; //end marker
00688 }
00689 
00690 #endif /* AVCODEC_SNOW_H */