/*
  * Copyright (C) 2004 Michael Niedermayer <michaelni@gmx.at>
  *

  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either

  * version 2.1 of the License, or (at your option) any later version.

  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */
 

 #include "libavutil/intmath.h"

 #include "libavutil/log.h"
 #include "libavutil/opt.h"

 #include "avcodec.h"

 #include "me_cmp.h"

 #include "snow_dwt.h"

 #include "internal.h"

 #include "snow.h"

 #include "snowdata.h"

 
 #include "rangecoder.h"

 #include "mathops.h"

 #include "h263.h"

 void ff_snow_inner_add_yblock(const uint8_t *obmc, const int obmc_stride, uint8_t * * block, int b_w, int b_h,
                               int src_x, int src_y, int src_stride, slice_buffer * sb, int add, uint8_t * dst8){
     int y, x;
     IDWTELEM * dst;
     for(y=0; y<b_h; y++){
         //FIXME ugly misuse of obmc_stride
         const uint8_t *obmc1= obmc + y*obmc_stride;
         const uint8_t *obmc2= obmc1+ (obmc_stride>>1);
         const uint8_t *obmc3= obmc1+ obmc_stride*(obmc_stride>>1);
         const uint8_t *obmc4= obmc3+ (obmc_stride>>1);
         dst = slice_buffer_get_line(sb, src_y + y);
         for(x=0; x<b_w; x++){
             int v=   obmc1[x] * block[3][x + y*src_stride]
                     +obmc2[x] * block[2][x + y*src_stride]
                     +obmc3[x] * block[1][x + y*src_stride]
                     +obmc4[x] * block[0][x + y*src_stride];

             v <<= 8 - LOG2_OBMC_MAX;
             if(FRAC_BITS != 8){
                 v >>= 8 - FRAC_BITS;

             }

             if(add){
                 v += dst[x + src_x];
                 v = (v + (1<<(FRAC_BITS-1))) >> FRAC_BITS;
                 if(v&(~255)) v= ~(v>>31);
                 dst8[x + y*src_stride] = v;

             }else{

                 dst[x + src_x] -= v;

             }
         }

     }

 }
 

 int ff_snow_get_buffer(SnowContext *s, AVFrame *frame)
 {
     int ret, i;

     int edges_needed = av_codec_is_encoder(s->avctx->codec);

     frame->width  = s->avctx->width ;
     frame->height = s->avctx->height;
     if (edges_needed) {
         frame->width  += 2 * EDGE_WIDTH;
         frame->height += 2 * EDGE_WIDTH;
     }

     if ((ret = ff_get_buffer(s->avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
         return ret;

     if (edges_needed) {
         for (i = 0; frame->data[i]; i++) {
             int offset = (EDGE_WIDTH >> (i ? s->chroma_v_shift : 0)) *
                             frame->linesize[i] +
                             (EDGE_WIDTH >> (i ? s->chroma_h_shift : 0));
             frame->data[i] += offset;
         }
         frame->width  = s->avctx->width;
         frame->height = s->avctx->height;

     }
 
     return 0;
 }
 

 void ff_snow_reset_contexts(SnowContext *s){ //FIXME better initial contexts

     int plane_index, level, orientation;
 

     for(plane_index=0; plane_index<3; plane_index++){

         for(level=0; level<MAX_DECOMPOSITIONS; level++){

             for(orientation=level ? 1:0; orientation<4; orientation++){

                 memset(s->plane[plane_index].band[level][orientation].state, MID_STATE, sizeof(s->plane[plane_index].band[level][orientation].state));

             }
         }
     }

     memset(s->header_state, MID_STATE, sizeof(s->header_state));
     memset(s->block_state, MID_STATE, sizeof(s->block_state));

 }
 

 int ff_snow_alloc_blocks(SnowContext *s){

     int w= AV_CEIL_RSHIFT(s->avctx->width,  LOG2_MB_SIZE);
     int h= AV_CEIL_RSHIFT(s->avctx->height, LOG2_MB_SIZE);

     s->b_width = w;
     s->b_height= h;

     av_free(s->block);

     s->block= av_mallocz_array(w * h,  sizeof(BlockNode) << (s->block_max_depth*2));

     if (!s->block)
         return AVERROR(ENOMEM);
 

     return 0;
 }
 

 static av_cold void init_qexp(void){

     int i;

     double v=128;

     for(i=0; i<QROOT; i++){

         ff_qexp[i]= lrintf(v);

         v *= pow(2, 1.0 / QROOT);

     }

 }

 static void mc_block(Plane *p, uint8_t *dst, const uint8_t *src, int stride, int b_w, int b_h, int dx, int dy){

     static const uint8_t weight[64]={

     8,7,6,5,4,3,2,1,
     7,7,0,0,0,0,0,1,
     6,0,6,0,0,0,2,0,
     5,0,0,5,0,3,0,0,
     4,0,0,0,4,0,0,0,
     3,0,0,5,0,3,0,0,
     2,0,6,0,0,0,2,0,
     1,7,0,0,0,0,0,1,
     };
 

     static const uint8_t brane[256]={

     0x00,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x11,0x12,0x12,0x12,0x12,0x12,0x12,0x12,
     0x04,0x05,0xcc,0xcc,0xcc,0xcc,0xcc,0x41,0x15,0x16,0xcc,0xcc,0xcc,0xcc,0xcc,0x52,
     0x04,0xcc,0x05,0xcc,0xcc,0xcc,0x41,0xcc,0x15,0xcc,0x16,0xcc,0xcc,0xcc,0x52,0xcc,
     0x04,0xcc,0xcc,0x05,0xcc,0x41,0xcc,0xcc,0x15,0xcc,0xcc,0x16,0xcc,0x52,0xcc,0xcc,
     0x04,0xcc,0xcc,0xcc,0x41,0xcc,0xcc,0xcc,0x15,0xcc,0xcc,0xcc,0x16,0xcc,0xcc,0xcc,
     0x04,0xcc,0xcc,0x41,0xcc,0x05,0xcc,0xcc,0x15,0xcc,0xcc,0x52,0xcc,0x16,0xcc,0xcc,
     0x04,0xcc,0x41,0xcc,0xcc,0xcc,0x05,0xcc,0x15,0xcc,0x52,0xcc,0xcc,0xcc,0x16,0xcc,
     0x04,0x41,0xcc,0xcc,0xcc,0xcc,0xcc,0x05,0x15,0x52,0xcc,0xcc,0xcc,0xcc,0xcc,0x16,
     0x44,0x45,0x45,0x45,0x45,0x45,0x45,0x45,0x55,0x56,0x56,0x56,0x56,0x56,0x56,0x56,
     0x48,0x49,0xcc,0xcc,0xcc,0xcc,0xcc,0x85,0x59,0x5A,0xcc,0xcc,0xcc,0xcc,0xcc,0x96,
     0x48,0xcc,0x49,0xcc,0xcc,0xcc,0x85,0xcc,0x59,0xcc,0x5A,0xcc,0xcc,0xcc,0x96,0xcc,
     0x48,0xcc,0xcc,0x49,0xcc,0x85,0xcc,0xcc,0x59,0xcc,0xcc,0x5A,0xcc,0x96,0xcc,0xcc,
     0x48,0xcc,0xcc,0xcc,0x49,0xcc,0xcc,0xcc,0x59,0xcc,0xcc,0xcc,0x96,0xcc,0xcc,0xcc,
     0x48,0xcc,0xcc,0x85,0xcc,0x49,0xcc,0xcc,0x59,0xcc,0xcc,0x96,0xcc,0x5A,0xcc,0xcc,
     0x48,0xcc,0x85,0xcc,0xcc,0xcc,0x49,0xcc,0x59,0xcc,0x96,0xcc,0xcc,0xcc,0x5A,0xcc,
     0x48,0x85,0xcc,0xcc,0xcc,0xcc,0xcc,0x49,0x59,0x96,0xcc,0xcc,0xcc,0xcc,0xcc,0x5A,
     };
 

     static const uint8_t needs[16]={

     0,1,0,0,
     2,4,2,0,
     0,1,0,0,
     15
     };
 
     int x, y, b, r, l;

     int16_t tmpIt   [64*(32+HTAPS_MAX)];

     uint8_t tmp2t[3][64*(32+HTAPS_MAX)];

     int16_t *tmpI= tmpIt;
     uint8_t *tmp2= tmp2t[0];

     const uint8_t *hpel[11];

     av_assert2(dx<16 && dy<16);

     r= brane[dx + 16*dy]&15;
     l= brane[dx + 16*dy]>>4;
 
     b= needs[l] | needs[r];

     if(p && !p->diag_mc)
         b= 15;

 
     if(b&5){

         for(y=0; y < b_h+HTAPS_MAX-1; y++){

             for(x=0; x < b_w; x++){

                 int a_1=src[x + HTAPS_MAX/2-4];
                 int a0= src[x + HTAPS_MAX/2-3];
                 int a1= src[x + HTAPS_MAX/2-2];
                 int a2= src[x + HTAPS_MAX/2-1];
                 int a3= src[x + HTAPS_MAX/2+0];
                 int a4= src[x + HTAPS_MAX/2+1];
                 int a5= src[x + HTAPS_MAX/2+2];
                 int a6= src[x + HTAPS_MAX/2+3];

                 int am=0;
                 if(!p || p->fast_mc){
                     am= 20*(a2+a3) - 5*(a1+a4) + (a0+a5);
                     tmpI[x]= am;
                     am= (am+16)>>5;
                 }else{
                     am= p->hcoeff[0]*(a2+a3) + p->hcoeff[1]*(a1+a4) + p->hcoeff[2]*(a0+a5) + p->hcoeff[3]*(a_1+a6);
                     tmpI[x]= am;
                     am= (am+32)>>6;
                 }

                 if(am&(~255)) am= ~(am>>31);
                 tmp2[x]= am;
             }
             tmpI+= 64;

             tmp2+= 64;

             src += stride;

         }

         src -= stride*y;

     }

     src += HTAPS_MAX/2 - 1;

     tmp2= tmp2t[1];

     if(b&2){

         for(y=0; y < b_h; y++){
             for(x=0; x < b_w+1; x++){

                 int a_1=src[x + (HTAPS_MAX/2-4)*stride];
                 int a0= src[x + (HTAPS_MAX/2-3)*stride];
                 int a1= src[x + (HTAPS_MAX/2-2)*stride];
                 int a2= src[x + (HTAPS_MAX/2-1)*stride];
                 int a3= src[x + (HTAPS_MAX/2+0)*stride];
                 int a4= src[x + (HTAPS_MAX/2+1)*stride];
                 int a5= src[x + (HTAPS_MAX/2+2)*stride];
                 int a6= src[x + (HTAPS_MAX/2+3)*stride];

                 int am=0;
                 if(!p || p->fast_mc)
                     am= (20*(a2+a3) - 5*(a1+a4) + (a0+a5) + 16)>>5;
                 else
                     am= (p->hcoeff[0]*(a2+a3) + p->hcoeff[1]*(a1+a4) + p->hcoeff[2]*(a0+a5) + p->hcoeff[3]*(a_1+a6) + 32)>>6;

                 if(am&(~255)) am= ~(am>>31);
                 tmp2[x]= am;
             }
             src += stride;

             tmp2+= 64;

         }

         src -= stride*y;

     }

     src += stride*(HTAPS_MAX/2 - 1);

     tmp2= tmp2t[2];
     tmpI= tmpIt;
     if(b&4){
         for(y=0; y < b_h; y++){
             for(x=0; x < b_w; x++){

                 int a_1=tmpI[x + (HTAPS_MAX/2-4)*64];
                 int a0= tmpI[x + (HTAPS_MAX/2-3)*64];
                 int a1= tmpI[x + (HTAPS_MAX/2-2)*64];
                 int a2= tmpI[x + (HTAPS_MAX/2-1)*64];
                 int a3= tmpI[x + (HTAPS_MAX/2+0)*64];
                 int a4= tmpI[x + (HTAPS_MAX/2+1)*64];
                 int a5= tmpI[x + (HTAPS_MAX/2+2)*64];
                 int a6= tmpI[x + (HTAPS_MAX/2+3)*64];

                 int am=0;
                 if(!p || p->fast_mc)
                     am= (20*(a2+a3) - 5*(a1+a4) + (a0+a5) + 512)>>10;
                 else
                     am= (p->hcoeff[0]*(a2+a3) + p->hcoeff[1]*(a1+a4) + p->hcoeff[2]*(a0+a5) + p->hcoeff[3]*(a_1+a6) + 2048)>>12;

                 if(am&(~255)) am= ~(am>>31);
                 tmp2[x]= am;
             }
             tmpI+= 64;

             tmp2+= 64;

         }
     }

     hpel[ 0]= src;

     hpel[ 1]= tmp2t[0] + 64*(HTAPS_MAX/2-1);

     hpel[ 2]= src + 1;
 
     hpel[ 4]= tmp2t[1];
     hpel[ 5]= tmp2t[2];
     hpel[ 6]= tmp2t[1] + 1;
 
     hpel[ 8]= src + stride;

     hpel[ 9]= hpel[1] + 64;

     hpel[10]= hpel[8] + 1;
 

 #define MC_STRIDE(x) (needs[x] ? 64 : stride)
 

     if(b==15){

         int dxy = dx / 8 + dy / 8 * 4;
         const uint8_t *src1 = hpel[dxy    ];
         const uint8_t *src2 = hpel[dxy + 1];
         const uint8_t *src3 = hpel[dxy + 4];
         const uint8_t *src4 = hpel[dxy + 5];
         int stride1 = MC_STRIDE(dxy);
         int stride2 = MC_STRIDE(dxy + 1);
         int stride3 = MC_STRIDE(dxy + 4);
         int stride4 = MC_STRIDE(dxy + 5);

         dx&=7;
         dy&=7;
         for(y=0; y < b_h; y++){
             for(x=0; x < b_w; x++){
                 dst[x]= ((8-dx)*(8-dy)*src1[x] + dx*(8-dy)*src2[x]+
                          (8-dx)*   dy *src3[x] + dx*   dy *src4[x]+32)>>6;
             }

             src1+=stride1;
             src2+=stride2;
             src3+=stride3;
             src4+=stride4;

             dst +=stride;
         }
     }else{

         const uint8_t *src1= hpel[l];
         const uint8_t *src2= hpel[r];

         int stride1 = MC_STRIDE(l);
         int stride2 = MC_STRIDE(r);

         int a= weight[((dx&7) + (8*(dy&7)))];
         int b= 8-a;
         for(y=0; y < b_h; y++){
             for(x=0; x < b_w; x++){
                 dst[x]= (a*src1[x] + b*src2[x] + 4)>>3;
             }

             src1+=stride1;
             src2+=stride2;

             dst +=stride;

         }
     }
 }
 

 void ff_snow_pred_block(SnowContext *s, uint8_t *dst, uint8_t *tmp, ptrdiff_t stride, int sx, int sy, int b_w, int b_h, const BlockNode *block, int plane_index, int w, int h){

     if(block->type & BLOCK_INTRA){

         int x, y;

         const unsigned color  = block->color[plane_index];
         const unsigned color4 = color*0x01010101;

         if(b_w==32){
             for(y=0; y < b_h; y++){
                 *(uint32_t*)&dst[0 + y*stride]= color4;
                 *(uint32_t*)&dst[4 + y*stride]= color4;
                 *(uint32_t*)&dst[8 + y*stride]= color4;
                 *(uint32_t*)&dst[12+ y*stride]= color4;
                 *(uint32_t*)&dst[16+ y*stride]= color4;
                 *(uint32_t*)&dst[20+ y*stride]= color4;
                 *(uint32_t*)&dst[24+ y*stride]= color4;
                 *(uint32_t*)&dst[28+ y*stride]= color4;
             }
         }else if(b_w==16){

             for(y=0; y < b_h; y++){
                 *(uint32_t*)&dst[0 + y*stride]= color4;
                 *(uint32_t*)&dst[4 + y*stride]= color4;
                 *(uint32_t*)&dst[8 + y*stride]= color4;
                 *(uint32_t*)&dst[12+ y*stride]= color4;
             }
         }else if(b_w==8){
             for(y=0; y < b_h; y++){
                 *(uint32_t*)&dst[0 + y*stride]= color4;
                 *(uint32_t*)&dst[4 + y*stride]= color4;
             }
         }else if(b_w==4){
             for(y=0; y < b_h; y++){
                 *(uint32_t*)&dst[0 + y*stride]= color4;
             }
         }else{
             for(y=0; y < b_h; y++){
                 for(x=0; x < b_w; x++){
                     dst[x + y*stride]= color;
                 }

             }
         }
     }else{

         uint8_t *src= s->last_picture[block->ref]->data[plane_index];

         const int scale= plane_index ?  (2*s->mv_scale)>>s->chroma_h_shift : 2*s->mv_scale;

         int mx= block->mx*scale;
         int my= block->my*scale;

         const int dx= mx&15;
         const int dy= my&15;

         const int tab_index= 3 - (b_w>>2) + (b_w>>4);

         sx += (mx>>4) - (HTAPS_MAX/2-1);
         sy += (my>>4) - (HTAPS_MAX/2-1);

         src += sx + sy*stride;

         if(   (unsigned)sx >= FFMAX(w - b_w - (HTAPS_MAX-2), 0)
            || (unsigned)sy >= FFMAX(h - b_h - (HTAPS_MAX-2), 0)){

             s->vdsp.emulated_edge_mc(tmp + MB_SIZE, src,
                                      stride, stride,

                                      b_w+HTAPS_MAX-1, b_h+HTAPS_MAX-1,
                                      sx, sy, w, h);

             src= tmp + MB_SIZE;
         }

 
         av_assert2(s->chroma_h_shift == s->chroma_v_shift); // only one mv_scale
 

         av_assert2((tab_index>=0 && tab_index<4) || b_w==32);

         if(    (dx&3) || (dy&3)
             || !(b_w == b_h || 2*b_w == b_h || b_w == 2*b_h)
             || (b_w&(b_w-1))
             || b_w == 1
             || b_h == 1
             || !s->plane[plane_index].fast_mc )

             mc_block(&s->plane[plane_index], dst, src, stride, b_w, b_h, dx, dy);

         else if(b_w==32){
             int y;
             for(y=0; y<b_h; y+=16){

                 s->h264qpel.put_h264_qpel_pixels_tab[0][dy+(dx>>2)](dst + y*stride, src + 3 + (y+3)*stride,stride);
                 s->h264qpel.put_h264_qpel_pixels_tab[0][dy+(dx>>2)](dst + 16 + y*stride, src + 19 + (y+3)*stride,stride);

             }
         }else if(b_w==b_h)

             s->h264qpel.put_h264_qpel_pixels_tab[tab_index  ][dy+(dx>>2)](dst,src + 3 + 3*stride,stride);

         else if(b_w==2*b_h){

             s->h264qpel.put_h264_qpel_pixels_tab[tab_index+1][dy+(dx>>2)](dst    ,src + 3       + 3*stride,stride);
             s->h264qpel.put_h264_qpel_pixels_tab[tab_index+1][dy+(dx>>2)](dst+b_h,src + 3 + b_h + 3*stride,stride);

         }else{

             av_assert2(2*b_w==b_h);

             s->h264qpel.put_h264_qpel_pixels_tab[tab_index  ][dy+(dx>>2)](dst           ,src + 3 + 3*stride           ,stride);
             s->h264qpel.put_h264_qpel_pixels_tab[tab_index  ][dy+(dx>>2)](dst+b_w*stride,src + 3 + 3*stride+b_w*stride,stride);

         }

     }
 }
 

 #define mca(dx,dy,b_w)\

 static void mc_block_hpel ## dx ## dy ## b_w(uint8_t *dst, const uint8_t *src, ptrdiff_t stride, int h){\

     av_assert2(h==b_w);\

     mc_block(NULL, dst, src-(HTAPS_MAX/2-1)-(HTAPS_MAX/2-1)*stride, stride, b_w, b_w, dx, dy);\

 }
 

 mca( 0, 0,16)
 mca( 8, 0,16)
 mca( 0, 8,16)
 mca( 8, 8,16)
 mca( 0, 0,8)
 mca( 8, 0,8)
 mca( 0, 8,8)
 mca( 8, 8,8)

 av_cold int ff_snow_common_init(AVCodecContext *avctx){

     SnowContext *s = avctx->priv_data;
     int width, height;

     int i, j;

 
     s->avctx= avctx;

     s->max_ref_frames=1; //just make sure it's not an invalid value in case of no initial keyframe

     s->spatial_decomposition_count = 1;

     ff_me_cmp_init(&s->mecc, avctx);

     ff_hpeldsp_init(&s->hdsp, avctx->flags);

     ff_videodsp_init(&s->vdsp, 8);

     ff_dwt_init(&s->dwt);

     ff_h264qpel_init(&s->h264qpel, 8);

 
 #define mcf(dx,dy)\

     s->qdsp.put_qpel_pixels_tab       [0][dy+dx/4]=\
     s->qdsp.put_no_rnd_qpel_pixels_tab[0][dy+dx/4]=\

         s->h264qpel.put_h264_qpel_pixels_tab[0][dy+dx/4];\

     s->qdsp.put_qpel_pixels_tab       [1][dy+dx/4]=\
     s->qdsp.put_no_rnd_qpel_pixels_tab[1][dy+dx/4]=\

         s->h264qpel.put_h264_qpel_pixels_tab[1][dy+dx/4];

 
     mcf( 0, 0)
     mcf( 4, 0)
     mcf( 8, 0)
     mcf(12, 0)
     mcf( 0, 4)
     mcf( 4, 4)
     mcf( 8, 4)
     mcf(12, 4)
     mcf( 0, 8)
     mcf( 4, 8)
     mcf( 8, 8)
     mcf(12, 8)
     mcf( 0,12)
     mcf( 4,12)
     mcf( 8,12)
     mcf(12,12)
 
 #define mcfh(dx,dy)\

     s->hdsp.put_pixels_tab       [0][dy/4+dx/8]=\
     s->hdsp.put_no_rnd_pixels_tab[0][dy/4+dx/8]=\

         mc_block_hpel ## dx ## dy ## 16;\

     s->hdsp.put_pixels_tab       [1][dy/4+dx/8]=\
     s->hdsp.put_no_rnd_pixels_tab[1][dy/4+dx/8]=\

         mc_block_hpel ## dx ## dy ## 8;
 
     mcfh(0, 0)
     mcfh(8, 0)
     mcfh(0, 8)
     mcfh(8, 8)
 

     init_qexp();

 
 //    dec += FFMAX(s->chroma_h_shift, s->chroma_v_shift);
 
     width= s->avctx->width;
     height= s->avctx->height;
 

     FF_ALLOCZ_ARRAY_OR_GOTO(avctx, s->spatial_idwt_buffer, width, height * sizeof(IDWTELEM), fail);
     FF_ALLOCZ_ARRAY_OR_GOTO(avctx, s->spatial_dwt_buffer,  width, height * sizeof(DWTELEM),  fail); //FIXME this does not belong here
     FF_ALLOCZ_ARRAY_OR_GOTO(avctx, s->temp_dwt_buffer,     width, sizeof(DWTELEM),  fail);
     FF_ALLOCZ_ARRAY_OR_GOTO(avctx, s->temp_idwt_buffer,    width, sizeof(IDWTELEM), fail);
     FF_ALLOC_ARRAY_OR_GOTO(avctx,  s->run_buffer,          ((width + 1) >> 1), ((height + 1) >> 1) * sizeof(*s->run_buffer), fail);

     for(i=0; i<MAX_REF_FRAMES; i++) {

         for(j=0; j<MAX_REF_FRAMES; j++)

             ff_scale_mv_ref[i][j] = 256*(i+1)/(j+1);

         s->last_picture[i] = av_frame_alloc();

         if (!s->last_picture[i])
             goto fail;

     }
 

     s->mconly_picture = av_frame_alloc();
     s->current_picture = av_frame_alloc();

     if (!s->mconly_picture || !s->current_picture)
         goto fail;

 
     return 0;

 fail:
     return AVERROR(ENOMEM);

 }
 

 int ff_snow_common_init_after_header(AVCodecContext *avctx) {

     SnowContext *s = avctx->priv_data;
     int plane_index, level, orientation;

     int ret, emu_buf_size;
 
     if(!s->scratchbuf) {

         if ((ret = ff_get_buffer(s->avctx, s->mconly_picture,

                                  AV_GET_BUFFER_FLAG_REF)) < 0)

             return ret;

         FF_ALLOCZ_ARRAY_OR_GOTO(avctx, s->scratchbuf, FFMAX(s->mconly_picture->linesize[0], 2*avctx->width+256), 7*MB_SIZE, fail);

         emu_buf_size = FFMAX(s->mconly_picture->linesize[0], 2*avctx->width+256) * (2 * MB_SIZE + HTAPS_MAX - 1);

         FF_ALLOC_OR_GOTO(avctx, s->emu_edge_buffer, emu_buf_size, fail);
     }
 

     if(s->mconly_picture->format != avctx->pix_fmt) {

         av_log(avctx, AV_LOG_ERROR, "pixel format changed\n");
         return AVERROR_INVALIDDATA;
     }

     for(plane_index=0; plane_index < s->nb_planes; plane_index++){

         int w= s->avctx->width;
         int h= s->avctx->height;
 
         if(plane_index){

             w = AV_CEIL_RSHIFT(w, s->chroma_h_shift);
             h = AV_CEIL_RSHIFT(h, s->chroma_v_shift);

         }
         s->plane[plane_index].width = w;
         s->plane[plane_index].height= h;
 
         for(level=s->spatial_decomposition_count-1; level>=0; level--){
             for(orientation=level ? 1 : 0; orientation<4; orientation++){
                 SubBand *b= &s->plane[plane_index].band[level][orientation];
 
                 b->buf= s->spatial_dwt_buffer;
                 b->level= level;
                 b->stride= s->plane[plane_index].width << (s->spatial_decomposition_count - level);
                 b->width = (w + !(orientation&1))>>1;
                 b->height= (h + !(orientation>1))>>1;
 
                 b->stride_line = 1 << (s->spatial_decomposition_count - level);
                 b->buf_x_offset = 0;
                 b->buf_y_offset = 0;
 
                 if(orientation&1){
                     b->buf += (w+1)>>1;
                     b->buf_x_offset = (w+1)>>1;
                 }
                 if(orientation>1){
                     b->buf += b->stride>>1;
                     b->buf_y_offset = b->stride_line >> 1;
                 }
                 b->ibuf= s->spatial_idwt_buffer + (b->buf - s->spatial_dwt_buffer);
 
                 if(level)
                     b->parent= &s->plane[plane_index].band[level-1][orientation];
                 //FIXME avoid this realloc
                 av_freep(&b->x_coeff);

                 b->x_coeff=av_mallocz_array(((b->width+1) * b->height+1), sizeof(x_and_coeff));

                 if (!b->x_coeff)
                     goto fail;

             }
             w= (w+1)>>1;
             h= (h+1)>>1;
         }
     }
 
     return 0;

 fail:
     return AVERROR(ENOMEM);

 }
 
 #define USE_HALFPEL_PLANE 0
 

 static int halfpel_interpol(SnowContext *s, uint8_t *halfpel[4][4], AVFrame *frame){

     int p,x,y;
 

     for(p=0; p < s->nb_planes; p++){

         int is_chroma= !!p;

         int w= is_chroma ? AV_CEIL_RSHIFT(s->avctx->width,  s->chroma_h_shift) : s->avctx->width;
         int h= is_chroma ? AV_CEIL_RSHIFT(s->avctx->height, s->chroma_v_shift) : s->avctx->height;

         int ls= frame->linesize[p];
         uint8_t *src= frame->data[p];
 

         halfpel[1][p] = av_malloc_array(ls, (h + 2 * EDGE_WIDTH));
         halfpel[2][p] = av_malloc_array(ls, (h + 2 * EDGE_WIDTH));
         halfpel[3][p] = av_malloc_array(ls, (h + 2 * EDGE_WIDTH));
         if (!halfpel[1][p] || !halfpel[2][p] || !halfpel[3][p]) {
             av_freep(&halfpel[1][p]);
             av_freep(&halfpel[2][p]);
             av_freep(&halfpel[3][p]);

             return AVERROR(ENOMEM);

         }
         halfpel[1][p] += EDGE_WIDTH * (1 + ls);
         halfpel[2][p] += EDGE_WIDTH * (1 + ls);
         halfpel[3][p] += EDGE_WIDTH * (1 + ls);

 
         halfpel[0][p]= src;
         for(y=0; y<h; y++){
             for(x=0; x<w; x++){
                 int i= y*ls + x;
 
                 halfpel[1][p][i]= (20*(src[i] + src[i+1]) - 5*(src[i-1] + src[i+2]) + (src[i-2] + src[i+3]) + 16 )>>5;
             }
         }
         for(y=0; y<h; y++){
             for(x=0; x<w; x++){
                 int i= y*ls + x;
 
                 halfpel[2][p][i]= (20*(src[i] + src[i+ls]) - 5*(src[i-ls] + src[i+2*ls]) + (src[i-2*ls] + src[i+3*ls]) + 16 )>>5;
             }
         }
         src= halfpel[1][p];
         for(y=0; y<h; y++){
             for(x=0; x<w; x++){
                 int i= y*ls + x;
 
                 halfpel[3][p][i]= (20*(src[i] + src[i+ls]) - 5*(src[i-ls] + src[i+2*ls]) + (src[i-2*ls] + src[i+3*ls]) + 16 )>>5;
             }
         }
 
 //FIXME border!
     }

     return 0;

 }
 

 void ff_snow_release_buffer(AVCodecContext *avctx)
 {

     SnowContext *s = avctx->priv_data;
     int i;
 

     if(s->last_picture[s->max_ref_frames-1]->data[0]){
         av_frame_unref(s->last_picture[s->max_ref_frames-1]);

         for(i=0; i<9; i++)

             if(s->halfpel_plane[s->max_ref_frames-1][1+i/3][i%3]) {

                 av_free(s->halfpel_plane[s->max_ref_frames-1][1+i/3][i%3] - EDGE_WIDTH*(1+s->current_picture->linesize[i%3]));

                 s->halfpel_plane[s->max_ref_frames-1][1+i/3][i%3] = NULL;
             }

     }
 }
 

 int ff_snow_frame_start(SnowContext *s){

    AVFrame *tmp;

    int i, ret;

     ff_snow_release_buffer(s->avctx);

     tmp= s->last_picture[s->max_ref_frames-1];

     for(i=s->max_ref_frames-1; i>0; i--)

         s->last_picture[i] = s->last_picture[i-1];

     memmove(s->halfpel_plane+1, s->halfpel_plane, (s->max_ref_frames-1)*sizeof(void*)*4*4);

     if(USE_HALFPEL_PLANE && s->current_picture->data[0]) {
         if((ret = halfpel_interpol(s, s->halfpel_plane[0], s->current_picture)) < 0)

             return ret;
     }

     s->last_picture[0] = s->current_picture;
     s->current_picture = tmp;

 
     if(s->keyframe){
         s->ref_frames= 0;
     }else{
         int i;

         for(i=0; i<s->max_ref_frames && s->last_picture[i]->data[0]; i++)
             if(i && s->last_picture[i-1]->key_frame)

                 break;
         s->ref_frames= i;
         if(s->ref_frames==0){
             av_log(s->avctx,AV_LOG_ERROR, "No reference frames\n");

             return AVERROR_INVALIDDATA;

         }
     }

     if ((ret = ff_snow_get_buffer(s, s->current_picture)) < 0)

         return ret;

     s->current_picture->key_frame= s->keyframe;

 
     return 0;
 }
 

 av_cold void ff_snow_common_end(SnowContext *s)
 {

     int plane_index, level, orientation, i;
 
     av_freep(&s->spatial_dwt_buffer);

     av_freep(&s->temp_dwt_buffer);

     av_freep(&s->spatial_idwt_buffer);

     av_freep(&s->temp_idwt_buffer);

     av_freep(&s->run_buffer);

 
     s->m.me.temp= NULL;
     av_freep(&s->m.me.scratchpad);
     av_freep(&s->m.me.map);
     av_freep(&s->m.me.score_map);

     av_freep(&s->m.sc.obmc_scratchpad);

 
     av_freep(&s->block);
     av_freep(&s->scratchbuf);

     av_freep(&s->emu_edge_buffer);

 
     for(i=0; i<MAX_REF_FRAMES; i++){
         av_freep(&s->ref_mvs[i]);
         av_freep(&s->ref_scores[i]);

         if(s->last_picture[i] && s->last_picture[i]->data[0]) {

             av_assert0(s->last_picture[i]->data[0] != s->current_picture->data[0]);

         }

         av_frame_free(&s->last_picture[i]);

     }
 

     for(plane_index=0; plane_index < MAX_PLANES; plane_index++){
         for(level=MAX_DECOMPOSITIONS-1; level>=0; level--){

             for(orientation=level ? 1 : 0; orientation<4; orientation++){
                 SubBand *b= &s->plane[plane_index].band[level][orientation];
 
                 av_freep(&b->x_coeff);
             }
         }
     }

     av_frame_free(&s->mconly_picture);
     av_frame_free(&s->current_picture);

 }