text: /*
   * RV40 decoder
   * Copyright (c) 2007 Konstantin Shishkov
   *
   * 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
   */
  
  /**
   * @file
   * RV40 decoder
   */
  
  #include "libavutil/imgutils.h"
  
  #include "avcodec.h"
  #include "mpegutils.h"
  #include "mpegvideo.h"
  #include "golomb.h"
  
  #include "rv34.h"
  #include "rv40vlc2.h"
  #include "rv40data.h"
  
  static VLC aic_top_vlc;
  static VLC aic_mode1_vlc[AIC_MODE1_NUM], aic_mode2_vlc[AIC_MODE2_NUM];
  static VLC ptype_vlc[NUM_PTYPE_VLCS], btype_vlc[NUM_BTYPE_VLCS];
  
  static const int16_t mode2_offs[] = {
         0,  614, 1222, 1794, 2410,  3014,  3586,  4202,  4792, 5382, 5966, 6542,
      7138, 7716, 8292, 8864, 9444, 10030, 10642, 11212, 11814
  };
  
  /**
   * Initialize all tables.
   */
  static av_cold void rv40_init_tables(void)
  {
      int i;
      static VLC_TYPE aic_table[1 << AIC_TOP_BITS][2];
      static VLC_TYPE aic_mode1_table[AIC_MODE1_NUM << AIC_MODE1_BITS][2];
      static VLC_TYPE aic_mode2_table[11814][2];
      static VLC_TYPE ptype_table[NUM_PTYPE_VLCS << PTYPE_VLC_BITS][2];
      static VLC_TYPE btype_table[NUM_BTYPE_VLCS << BTYPE_VLC_BITS][2];
  
      aic_top_vlc.table = aic_table;
      aic_top_vlc.table_allocated = 1 << AIC_TOP_BITS;
      init_vlc(&aic_top_vlc, AIC_TOP_BITS, AIC_TOP_SIZE,
               rv40_aic_top_vlc_bits,  1, 1,
               rv40_aic_top_vlc_codes, 1, 1, INIT_VLC_USE_NEW_STATIC);
      for(i = 0; i < AIC_MODE1_NUM; i++){
          // Every tenth VLC table is empty
          if((i % 10) == 9) continue;
          aic_mode1_vlc[i].table = &aic_mode1_table[i << AIC_MODE1_BITS];
          aic_mode1_vlc[i].table_allocated = 1 << AIC_MODE1_BITS;
          init_vlc(&aic_mode1_vlc[i], AIC_MODE1_BITS, AIC_MODE1_SIZE,
                   aic_mode1_vlc_bits[i],  1, 1,
                   aic_mode1_vlc_codes[i], 1, 1, INIT_VLC_USE_NEW_STATIC);
      }
      for(i = 0; i < AIC_MODE2_NUM; i++){
          aic_mode2_vlc[i].table = &aic_mode2_table[mode2_offs[i]];
          aic_mode2_vlc[i].table_allocated = mode2_offs[i + 1] - mode2_offs[i];
          init_vlc(&aic_mode2_vlc[i], AIC_MODE2_BITS, AIC_MODE2_SIZE,
                   aic_mode2_vlc_bits[i],  1, 1,
                   aic_mode2_vlc_codes[i], 2, 2, INIT_VLC_USE_NEW_STATIC);
      }
      for(i = 0; i < NUM_PTYPE_VLCS; i++){
          ptype_vlc[i].table = &ptype_table[i << PTYPE_VLC_BITS];
          ptype_vlc[i].table_allocated = 1 << PTYPE_VLC_BITS;
          ff_init_vlc_sparse(&ptype_vlc[i], PTYPE_VLC_BITS, PTYPE_VLC_SIZE,
                              ptype_vlc_bits[i],  1, 1,
                              ptype_vlc_codes[i], 1, 1,
                              ptype_vlc_syms,     1, 1, INIT_VLC_USE_NEW_STATIC);
      }
      for(i = 0; i < NUM_BTYPE_VLCS; i++){
          btype_vlc[i].table = &btype_table[i << BTYPE_VLC_BITS];
          btype_vlc[i].table_allocated = 1 << BTYPE_VLC_BITS;
          ff_init_vlc_sparse(&btype_vlc[i], BTYPE_VLC_BITS, BTYPE_VLC_SIZE,
                              btype_vlc_bits[i],  1, 1,
                              btype_vlc_codes[i], 1, 1,
                              btype_vlc_syms,     1, 1, INIT_VLC_USE_NEW_STATIC);
      }
  }
  
  /**
   * Get stored dimension from bitstream.
   *
   * If the width/height is the standard one then it's coded as a 3-bit index.
   * Otherwise it is coded as escaped 8-bit portions.
   */
  static int get_dimension(GetBitContext *gb, const int *dim)
  {
      int t   = get_bits(gb, 3);
      int val = dim[t];
      if(val < 0)
          val = dim[get_bits1(gb) - val];
      if(!val){
          do{
              t = get_bits(gb, 8);
              val += t << 2;
          }while(t == 0xFF);
      }
      return val;
  }
  
  /**
   * Get encoded picture size - usually this is called from rv40_parse_slice_header.
   */
  static void rv40_parse_picture_size(GetBitContext *gb, int *w, int *h)
  {
      *w = get_dimension(gb, rv40_standard_widths);
      *h = get_dimension(gb, rv40_standard_heights);
  }
  
  static int rv40_parse_slice_header(RV34DecContext *r, GetBitContext *gb, SliceInfo *si)
  {
      int mb_bits;
      int w = r->s.width, h = r->s.height;
      int mb_size;
      int ret;
  
      memset(si, 0, sizeof(SliceInfo));
      if(get_bits1(gb))
          return AVERROR_INVALIDDATA;
      si->type = get_bits(gb, 2);
      if(si->type == 1) si->type = 0;
      si->quant = get_bits(gb, 5);
      if(get_bits(gb, 2))
          return AVERROR_INVALIDDATA;
      si->vlc_set = get_bits(gb, 2);
      skip_bits1(gb);
      si->pts = get_bits(gb, 13);
      if(!si->type || !get_bits1(gb))
          rv40_parse_picture_size(gb, &w, &h);
      if ((ret = av_image_check_size(w, h, 0, r->s.avctx)) < 0)
          return ret;
      si->width  = w;
      si->height = h;
      mb_size = ((w + 15) >> 4) * ((h + 15) >> 4);
      mb_bits = ff_rv34_get_start_offset(gb, mb_size);
      si->start = get_bits(gb, mb_bits);
  
      return 0;
  }
  
  /**
   * Decode 4x4 intra types array.
   */
  static int rv40_decode_intra_types(RV34DecContext *r, GetBitContext *gb, int8_t *dst)
  {
      MpegEncContext *s = &r->s;
      int i, j, k, v;
      int A, B, C;
      int pattern;
      int8_t *ptr;
  
      for(i = 0; i < 4; i++, dst += r->intra_types_stride){
          if(!i && s->first_slice_line){
              pattern = get_vlc2(gb, aic_top_vlc.table, AIC_TOP_BITS, 1);
              dst[0] = (pattern >> 2) & 2;
              dst[1] = (pattern >> 1) & 2;
              dst[2] =  pattern       & 2;
              dst[3] = (pattern << 1) & 2;
              continue;
          }
          ptr = dst;
          for(j = 0; j < 4; j++){
              /* Coefficients are read using VLC chosen by the prediction pattern
               * The first one (used for retrieving a pair of coefficients) is
               * constructed from the top, top right and left coefficients
               * The second one (used for retrieving only one coefficient) is
               * top + 10 * left.
               */
              A = ptr[-r->intra_types_stride + 1]; // it won't be used for the last coefficient in a row
              B = ptr[-r->intra_types_stride];
              C = ptr[-1];
              pattern = A + (B << 4) + (C << 8);
              for(k = 0; k < MODE2_PATTERNS_NUM; k++)
                  if(pattern == rv40_aic_table_index[k])
                      break;
              if(j < 3 && k < MODE2_PATTERNS_NUM){ //pattern is found, decoding 2 coefficients
                  v = get_vlc2(gb, aic_mode2_vlc[k].table, AIC_MODE2_BITS, 2);
                  *ptr++ = v/9;
                  *ptr++ = v%9;
                  j++;
              }else{
                  if(B != -1 && C != -1)
                      v = get_vlc2(gb, aic_mode1_vlc[B + C*10].table, AIC_MODE1_BITS, 1);
                  else{ // tricky decoding
                      v = 0;
                      switch(C){
                      case -1: // code 0 -> 1, 1 -> 0
                          if(B < 2)
                              v = get_bits1(gb) ^ 1;
                          break;
                      case  0:
                      case  2: // code 0 -> 2, 1 -> 0
                          v = (get_bits1(gb) ^ 1) << 1;
                          break;
                      }
                  }
                  *ptr++ = v;
              }
          }
      }
      return 0;
  }
  
  /**
   * Decode macroblock information.
   */
  static int rv40_decode_mb_info(RV34DecContext *r)
  {
      MpegEncContext *s = &r->s;
      GetBitContext *gb = &s->gb;
      int q, i;
      int prev_type = 0;
      int mb_pos = s->mb_x + s->mb_y * s->mb_stride;
  
      if(!r->s.mb_skip_run) {
          r->s.mb_skip_run = svq3_get_ue_golomb(gb) + 1;
          if(r->s.mb_skip_run > (unsigned)s->mb_num)
              return -1;
      }
  
      if(--r->s.mb_skip_run)
           return RV34_MB_SKIP;
  
      if(r->avail_cache[6-4]){
          int blocks[RV34_MB_TYPES] = {0};
          int count = 0;
          if(r->avail_cache[6-1])
              blocks[r->mb_type[mb_pos - 1]]++;
          blocks[r->mb_type[mb_pos - s->mb_stride]]++;
          if(r->avail_cache[6-2])
              blocks[r->mb_type[mb_pos - s->mb_stride + 1]]++;
          if(r->avail_cache[6-5])
              blocks[r->mb_type[mb_pos - s->mb_stride - 1]]++;
          for(i = 0; i < RV34_MB_TYPES; i++){
              if(blocks[i] > count){
                  count = blocks[i];
                  prev_type = i;
                  if(count>1)
                      break;
              }
          }
      } else if (r->avail_cache[6-1])
          prev_type = r->mb_type[mb_pos - 1];
  
      if(s->pict_type == AV_PICTURE_TYPE_P){
          prev_type = block_num_to_ptype_vlc_num[prev_type];
          q = get_vlc2(gb, ptype_vlc[prev_type].table, PTYPE_VLC_BITS, 1);
          if(q < PBTYPE_ESCAPE)
              return q;
          q = get_vlc2(gb, ptype_vlc[prev_type].table, PTYPE_VLC_BITS, 1);
          av_log(s->avctx, AV_LOG_ERROR, "Dquant for P-frame\n");
      }else{
          prev_type = block_num_to_btype_vlc_num[prev_type];
          q = get_vlc2(gb, btype_vlc[prev_type].table, BTYPE_VLC_BITS, 1);
          if(q < PBTYPE_ESCAPE)
              return q;
          q = get_vlc2(gb, btype_vlc[prev_type].table, BTYPE_VLC_BITS, 1);
          av_log(s->avctx, AV_LOG_ERROR, "Dquant for B-frame\n");
      }
      return 0;
  }
  
  enum RV40BlockPos{
      POS_CUR,
      POS_TOP,
      POS_LEFT,
      POS_BOTTOM,
  };
  
  #define MASK_CUR          0x0001
  #define MASK_RIGHT        0x0008
  #define MASK_BOTTOM       0x0010
  #define MASK_TOP          0x1000
  #define MASK_Y_TOP_ROW    0x000F
  #define MASK_Y_LAST_ROW   0xF000
  #define MASK_Y_LEFT_COL   0x1111
  #define MASK_Y_RIGHT_COL  0x8888
  #define MASK_C_TOP_ROW    0x0003
  #define MASK_C_LAST_ROW   0x000C
  #define MASK_C_LEFT_COL   0x0005
  #define MASK_C_RIGHT_COL  0x000A
  
  static const int neighbour_offs_x[4] = { 0,  0, -1, 0 };
  static const int neighbour_offs_y[4] = { 0, -1,  0, 1 };
  
  static void rv40_adaptive_loop_filter(RV34DSPContext *rdsp,
                                        uint8_t *src, int stride, int dmode,
                                        int lim_q1, int lim_p1,
                                        int alpha, int beta, int beta2,
                                        int chroma, int edge, int dir)
  {
      int filter_p1, filter_q1;
      int strong;
      int lims;
  
      strong = rdsp->rv40_loop_filter_strength[dir](src, stride, beta, beta2,
                                                    edge, &filter_p1, &filter_q1);
  
      lims = filter_p1 + filter_q1 + ((lim_q1 + lim_p1) >> 1) + 1;
  
      if (strong) {
          rdsp->rv40_strong_loop_filter[dir](src, stride, alpha,
                                             lims, dmode, chroma);
      } else if (filter_p1 & filter_q1) {
          rdsp->rv40_weak_loop_filter[dir](src, stride, 1, 1, alpha, beta,
                                           lims, lim_q1, lim_p1);
      } else if (filter_p1 | filter_q1) {
          rdsp->rv40_weak_loop_filter[dir](src, stride, filter_p1, filter_q1,
                                           alpha, beta, lims >> 1, lim_q1 >> 1,
                                           lim_p1 >> 1);
      }
  }
  
  /**
   * RV40 loop filtering function
   */
  static void rv40_loop_filter(RV34DecContext *r, int row)
  {
      MpegEncContext *s = &r->s;
      int mb_pos, mb_x;
      int i, j, k;
      uint8_t *Y, *C;
      int alpha, beta, betaY, betaC;
      int q;
      int mbtype[4];   ///< current macroblock and its neighbours types
      /**
       * flags indicating that macroblock can be filtered with strong filter
       * it is set only for intra coded MB and MB with DCs coded separately
       */
      int mb_strong[4];
      int clip[4];     ///< MB filter clipping value calculated from filtering strength
      /**
       * coded block patterns for luma part of current macroblock and its neighbours
       * Format:
       * LSB corresponds to the top left block,
       * each nibble represents one row of subblocks.
       */
      int cbp[4];
      /**
       * coded block patterns for chroma part of current macroblock and its neighbours
       * Format is the same as for luma with two subblocks in a row.
       */
      int uvcbp[4][2];
      /**
       * This mask represents the pattern of luma subblocks that should be filtered
       * in addition to the coded ones because they lie at the edge of
       * 8x8 block with different enough motion vectors
       */
      unsigned mvmasks[4];
  
      mb_pos = row * s->mb_stride;
      for(mb_x = 0; mb_x < s->mb_width; mb_x++, mb_pos++){
          int mbtype = s->current_picture_ptr->mb_type[mb_pos];
          if(IS_INTRA(mbtype) || IS_SEPARATE_DC(mbtype))
              r->cbp_luma  [mb_pos] = r->deblock_coefs[mb_pos] = 0xFFFF;
          if(IS_INTRA(mbtype))
              r->cbp_chroma[mb_pos] = 0xFF;
      }
      mb_pos = row * s->mb_stride;
      for(mb_x = 0; mb_x < s->mb_width; mb_x++, mb_pos++){
          int y_h_deblock, y_v_deblock;
          int c_v_deblock[2], c_h_deblock[2];
          int clip_left;
          int avail[4];
          unsigned y_to_deblock;
          int c_to_deblock[2];
  
          q = s->current_picture_ptr->qscale_table[mb_pos];
          alpha = rv40_alpha_tab[q];
          beta  = rv40_beta_tab [q];
          betaY = betaC = beta * 3;
          if(s->width * s->height <= 176*144)
              betaY += beta;
  
          avail[0] = 1;
          avail[1] = row;
          avail[2] = mb_x;
          avail[3] = row < s->mb_height - 1;
          for(i = 0; i < 4; i++){
              if(avail[i]){
                  int pos = mb_pos + neighbour_offs_x[i] + neighbour_offs_y[i]*s->mb_stride;
                  mvmasks[i] = r->deblock_coefs[pos];
                  mbtype [i] = s->current_picture_ptr->mb_type[pos];
                  cbp    [i] = r->cbp_luma[pos];
                  uvcbp[i][0] = r->cbp_chroma[pos] & 0xF;
                  uvcbp[i][1] = r->cbp_chroma[pos] >> 4;
              }else{
                  mvmasks[i] = 0;
                  mbtype [i] = mbtype[0];
                  cbp    [i] = 0;
                  uvcbp[i][0] = uvcbp[i][1] = 0;
              }
              mb_strong[i] = IS_INTRA(mbtype[i]) || IS_SEPARATE_DC(mbtype[i]);
              clip[i] = rv40_filter_clip_tbl[mb_strong[i] + 1][q];
          }
          y_to_deblock =  mvmasks[POS_CUR]
                       | (mvmasks[POS_BOTTOM] << 16);
          /* This pattern contains bits signalling that horizontal edges of
           * the current block can be filtered.
           * That happens when either of adjacent subblocks is coded or lies on
           * the edge of 8x8 blocks with motion vectors differing by more than
           * 3/4 pel in any component (any edge orientation for some reason).
           */
          y_h_deblock =   y_to_deblock
                      | ((cbp[POS_CUR]                           <<  4) & ~MASK_Y_TOP_ROW)
                      | ((cbp[POS_TOP]        & MASK_Y_LAST_ROW) >> 12);
          /* This pattern contains bits signalling that vertical edges of
           * the current block can be filtered.
           * That happens when either of adjacent subblocks is coded or lies on
           * the edge of 8x8 blocks with motion vectors differing by more than
           * 3/4 pel in any component (any edge orientation for some reason).
           */
          y_v_deblock =   y_to_deblock
                      | ((cbp[POS_CUR]                      << 1) & ~MASK_Y_LEFT_COL)
                      | ((cbp[POS_LEFT] & MASK_Y_RIGHT_COL) >> 3);
          if(!mb_x)
              y_v_deblock &= ~MASK_Y_LEFT_COL;
          if(!row)
              y_h_deblock &= ~MASK_Y_TOP_ROW;
          if(row == s->mb_height - 1 || (mb_strong[POS_CUR] | mb_strong[POS_BOTTOM]))
              y_h_deblock &= ~(MASK_Y_TOP_ROW << 16);
          /* Calculating chroma patterns is similar and easier since there is
           * no motion vector pattern for them.
           */
          for(i = 0; i < 2; i++){
              c_to_deblock[i] = (uvcbp[POS_BOTTOM][i] << 4) | uvcbp[POS_CUR][i];
              c_v_deblock[i] =   c_to_deblock[i]
                             | ((uvcbp[POS_CUR] [i]                       << 1) & ~MASK_C_LEFT_COL)
                             | ((uvcbp[POS_LEFT][i]   & MASK_C_RIGHT_COL) >> 1);
              c_h_deblock[i] =   c_to_deblock[i]
                             | ((uvcbp[POS_TOP][i]    & MASK_C_LAST_ROW)  >> 2)
                             |  (uvcbp[POS_CUR][i]                        << 2);
              if(!mb_x)
                  c_v_deblock[i] &= ~MASK_C_LEFT_COL;
              if(!row)
                  c_h_deblock[i] &= ~MASK_C_TOP_ROW;
              if(row == s->mb_height - 1 || (mb_strong[POS_CUR] | mb_strong[POS_BOTTOM]))
                  c_h_deblock[i] &= ~(MASK_C_TOP_ROW << 4);
          }
  
          for(j = 0; j < 16; j += 4){
              Y = s->current_picture_ptr->f->data[0] + mb_x*16 + (row*16 + j) * s->linesize;
              for(i = 0; i < 4; i++, Y += 4){
                  int ij = i + j;
                  int clip_cur = y_to_deblock & (MASK_CUR << ij) ? clip[POS_CUR] : 0;
                  int dither = j ? ij : i*4;
  
                  // if bottom block is coded then we can filter its top edge
                  // (or bottom edge of this block, which is the same)
                  if(y_h_deblock & (MASK_BOTTOM << ij)){
                      rv40_adaptive_loop_filter(&r->rdsp, Y+4*s->linesize,
                                                s->linesize, dither,
                                                y_to_deblock & (MASK_BOTTOM << ij) ? clip[POS_CUR] : 0,
                                                clip_cur, alpha, beta, betaY,
                                                0, 0, 0);
                  }
                  // filter left block edge in ordinary mode (with low filtering strength)
                  if(y_v_deblock & (MASK_CUR << ij) && (i || !(mb_strong[POS_CUR] | mb_strong[POS_LEFT]))){
                      if(!i)
                          clip_left = mvmasks[POS_LEFT] & (MASK_RIGHT << j) ? clip[POS_LEFT] : 0;
                      else
                          clip_left = y_to_deblock & (MASK_CUR << (ij-1)) ? clip[POS_CUR] : 0;
                      rv40_adaptive_loop_filter(&r->rdsp, Y, s->linesize, dither,
                                                clip_cur,
                                                clip_left,
                                                alpha, beta, betaY, 0, 0, 1);
                  }
                  // filter top edge of the current macroblock when filtering strength is high
                  if(!j && y_h_deblock & (MASK_CUR << i) && (mb_strong[POS_CUR] | mb_strong[POS_TOP])){
                      rv40_adaptive_loop_filter(&r->rdsp, Y, s->linesize, dither,
                                         clip_cur,
                                         mvmasks[POS_TOP] & (MASK_TOP << i) ? clip[POS_TOP] : 0,
                                         alpha, beta, betaY, 0, 1, 0);
                  }
                  // filter left block edge in edge mode (with high filtering strength)
                  if(y_v_deblock & (MASK_CUR << ij) && !i && (mb_strong[POS_CUR] | mb_strong[POS_LEFT])){
                      clip_left = mvmasks[POS_LEFT] & (MASK_RIGHT << j) ? clip[POS_LEFT] : 0;
                      rv40_adaptive_loop_filter(&r->rdsp, Y, s->linesize, dither,
                                         clip_cur,
                                         clip_left,
                                         alpha, beta, betaY, 0, 1, 1);
                  }
              }
          }
          for(k = 0; k < 2; k++){
              for(j = 0; j < 2; j++){
                  C = s->current_picture_ptr->f->data[k + 1] + mb_x*8 + (row*8 + j*4) * s->uvlinesize;
                  for(i = 0; i < 2; i++, C += 4){
                      int ij = i + j*2;
                      int clip_cur = c_to_deblock[k] & (MASK_CUR << ij) ? clip[POS_CUR] : 0;
                      if(c_h_deblock[k] & (MASK_CUR << (ij+2))){
                          int clip_bot = c_to_deblock[k] & (MASK_CUR << (ij+2)) ? clip[POS_CUR] : 0;
                          rv40_adaptive_loop_filter(&r->rdsp, C+4*s->uvlinesize, s->uvlinesize, i*8,
                                             clip_bot,
                                             clip_cur,
                                             alpha, beta, betaC, 1, 0, 0);
                      }
                      if((c_v_deblock[k] & (MASK_CUR << ij)) && (i || !(mb_strong[POS_CUR] | mb_strong[POS_LEFT]))){
                          if(!i)
                              clip_left = uvcbp[POS_LEFT][k] & (MASK_CUR << (2*j+1)) ? clip[POS_LEFT] : 0;
                          else
                              clip_left = c_to_deblock[k]    & (MASK_CUR << (ij-1))  ? clip[POS_CUR]  : 0;
                          rv40_adaptive_loop_filter(&r->rdsp, C, s->uvlinesize, j*8,
                                             clip_cur,
                                             clip_left,
                                             alpha, beta, betaC, 1, 0, 1);
                      }
                      if(!j && c_h_deblock[k] & (MASK_CUR << ij) && (mb_strong[POS_CUR] | mb_strong[POS_TOP])){
                          int clip_top = uvcbp[POS_TOP][k] & (MASK_CUR << (ij+2)) ? clip[POS_TOP] : 0;
                          rv40_adaptive_loop_filter(&r->rdsp, C, s->uvlinesize, i*8,
                                             clip_cur,
                                             clip_top,
                                             alpha, beta, betaC, 1, 1, 0);
                      }
                      if(c_v_deblock[k] & (MASK_CUR << ij) && !i && (mb_strong[POS_CUR] | mb_strong[POS_LEFT])){
                          clip_left = uvcbp[POS_LEFT][k] & (MASK_CUR << (2*j+1)) ? clip[POS_LEFT] : 0;
                          rv40_adaptive_loop_filter(&r->rdsp, C, s->uvlinesize, j*8,
                                             clip_cur,
                                             clip_left,
                                             alpha, beta, betaC, 1, 1, 1);
                      }
                  }
              }
          }
      }
  }
  
  /**
   * Initialize decoder.
   */
  static av_cold int rv40_decode_init(AVCodecContext *avctx)
  {
      RV34DecContext *r = avctx->priv_data;
      int ret;
  
      r->rv30 = 0;
      if ((ret = ff_rv34_decode_init(avctx)) < 0)
          return ret;
      if(!aic_top_vlc.bits)
          rv40_init_tables();
      r->parse_slice_header = rv40_parse_slice_header;
      r->decode_intra_types = rv40_decode_intra_types;
      r->decode_mb_info     = rv40_decode_mb_info;
      r->loop_filter        = rv40_loop_filter;
      r->luma_dc_quant_i = rv40_luma_dc_quant[0];
      r->luma_dc_quant_p = rv40_luma_dc_quant[1];
      return 0;
  }
  
  AVCodec ff_rv40_decoder = {
      .name                  = "rv40",
      .long_name             = NULL_IF_CONFIG_SMALL("RealVideo 4.0"),
      .type                  = AVMEDIA_TYPE_VIDEO,
      .id                    = AV_CODEC_ID_RV40,
      .priv_data_size        = sizeof(RV34DecContext),
      .init                  = rv40_decode_init,
      .close                 = ff_rv34_decode_end,
      .decode                = ff_rv34_decode_frame,
      .capabilities          = CODEC_CAP_DR1 | CODEC_CAP_DELAY |
                               CODEC_CAP_FRAME_THREADS,
      .flush                 = ff_mpeg_flush,
      .pix_fmts              = (const enum AVPixelFormat[]) {
          AV_PIX_FMT_YUV420P,
          AV_PIX_FMT_NONE
      },
      .init_thread_copy      = ONLY_IF_THREADS_ENABLED(ff_rv34_decode_init_thread_copy),
      .update_thread_context = ONLY_IF_THREADS_ENABLED(ff_rv34_decode_update_thread_context),
  };
  