text: /*
   * 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= FF_CEIL_RSHIFT(s->avctx->width,  LOG2_MB_SIZE);
      int h= FF_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>>= s->chroma_h_shift;
              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 ? s->avctx->width >>s->chroma_h_shift : s->avctx->width;
          int h= is_chroma ? 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 -1;
          }
      }
      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.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);
  }
  