text: /*
   * RV30/40 decoder common data
   * Copyright (c) 2007 Mike Melanson, 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
   * RV30/40 decoder common data
   */
  
  #include "libavutil/imgutils.h"
  #include "libavutil/internal.h"
  
  #include "avcodec.h"
  #include "error_resilience.h"
  #include "mpegutils.h"
  #include "mpegvideo.h"
  #include "golomb.h"
  #include "internal.h"
  #include "mathops.h"
  #include "mpeg_er.h"
  #include "qpeldsp.h"
  #include "rectangle.h"
  #include "thread.h"
  
  #include "rv34vlc.h"
  #include "rv34data.h"
  #include "rv34.h"
  
  static inline void ZERO8x2(void* dst, int stride)
  {
      fill_rectangle(dst,                 1, 2, stride, 0, 4);
      fill_rectangle(((uint8_t*)(dst))+4, 1, 2, stride, 0, 4);
  }
  
  /** translation of RV30/40 macroblock types to lavc ones */
  static const int rv34_mb_type_to_lavc[12] = {
      MB_TYPE_INTRA,
      MB_TYPE_INTRA16x16              | MB_TYPE_SEPARATE_DC,
      MB_TYPE_16x16   | MB_TYPE_L0,
      MB_TYPE_8x8     | MB_TYPE_L0,
      MB_TYPE_16x16   | MB_TYPE_L0,
      MB_TYPE_16x16   | MB_TYPE_L1,
      MB_TYPE_SKIP,
      MB_TYPE_DIRECT2 | MB_TYPE_16x16,
      MB_TYPE_16x8    | MB_TYPE_L0,
      MB_TYPE_8x16    | MB_TYPE_L0,
      MB_TYPE_16x16   | MB_TYPE_L0L1,
      MB_TYPE_16x16   | MB_TYPE_L0    | MB_TYPE_SEPARATE_DC
  };
  
  
  static RV34VLC intra_vlcs[NUM_INTRA_TABLES], inter_vlcs[NUM_INTER_TABLES];
  
  static int rv34_decode_mv(RV34DecContext *r, int block_type);
  
  /**
   * @name RV30/40 VLC generating functions
   * @{
   */
  
  static const int table_offs[] = {
        0,   1818,   3622,   4144,   4698,   5234,   5804,   5868,   5900,   5932,
     5996,   6252,   6316,   6348,   6380,   7674,   8944,  10274,  11668,  12250,
    14060,  15846,  16372,  16962,  17512,  18148,  18180,  18212,  18244,  18308,
    18564,  18628,  18660,  18692,  20036,  21314,  22648,  23968,  24614,  26384,
    28190,  28736,  29366,  29938,  30608,  30640,  30672,  30704,  30768,  31024,
    31088,  31120,  31184,  32570,  33898,  35236,  36644,  37286,  39020,  40802,
    41368,  42052,  42692,  43348,  43380,  43412,  43444,  43476,  43604,  43668,
    43700,  43732,  45100,  46430,  47778,  49160,  49802,  51550,  53340,  53972,
    54648,  55348,  55994,  56122,  56154,  56186,  56218,  56346,  56410,  56442,
    56474,  57878,  59290,  60636,  62036,  62682,  64460,  64524,  64588,  64716,
    64844,  66076,  67466,  67978,  68542,  69064,  69648,  70296,  72010,  72074,
    72138,  72202,  72330,  73572,  74936,  75454,  76030,  76566,  77176,  77822,
    79582,  79646,  79678,  79742,  79870,  81180,  82536,  83064,  83672,  84242,
    84934,  85576,  87384,  87448,  87480,  87544,  87672,  88982,  90340,  90902,
    91598,  92182,  92846,  93488,  95246,  95278,  95310,  95374,  95502,  96878,
    98266,  98848,  99542, 100234, 100884, 101524, 103320, 103352, 103384, 103416,
   103480, 104874, 106222, 106910, 107584, 108258, 108902, 109544, 111366, 111398,
   111430, 111462, 111494, 112878, 114320, 114988, 115660, 116310, 116950, 117592
  };
  
  static VLC_TYPE table_data[117592][2];
  
  /**
   * Generate VLC from codeword lengths.
   * @param bits   codeword lengths (zeroes are accepted)
   * @param size   length of input data
   * @param vlc    output VLC
   * @param insyms symbols for input codes (NULL for default ones)
   * @param num    VLC table number (for static initialization)
   */
  static void rv34_gen_vlc(const uint8_t *bits, int size, VLC *vlc, const uint8_t *insyms,
                           const int num)
  {
      int i;
      int counts[17] = {0}, codes[17];
      uint16_t cw[MAX_VLC_SIZE], syms[MAX_VLC_SIZE];
      uint8_t bits2[MAX_VLC_SIZE];
      int maxbits = 0, realsize = 0;
  
      for(i = 0; i < size; i++){
          if(bits[i]){
              bits2[realsize] = bits[i];
              syms[realsize] = insyms ? insyms[i] : i;
              realsize++;
              maxbits = FFMAX(maxbits, bits[i]);
              counts[bits[i]]++;
          }
      }
  
      codes[0] = 0;
      for(i = 0; i < 16; i++)
          codes[i+1] = (codes[i] + counts[i]) << 1;
      for(i = 0; i < realsize; i++)
          cw[i] = codes[bits2[i]]++;
  
      vlc->table = &table_data[table_offs[num]];
      vlc->table_allocated = table_offs[num + 1] - table_offs[num];
      ff_init_vlc_sparse(vlc, FFMIN(maxbits, 9), realsize,
                         bits2, 1, 1,
                         cw,    2, 2,
                         syms,  2, 2, INIT_VLC_USE_NEW_STATIC);
  }
  
  /**
   * Initialize all tables.
   */
  static av_cold void rv34_init_tables(void)
  {
      int i, j, k;
  
      for(i = 0; i < NUM_INTRA_TABLES; i++){
          for(j = 0; j < 2; j++){
              rv34_gen_vlc(rv34_table_intra_cbppat   [i][j], CBPPAT_VLC_SIZE,   &intra_vlcs[i].cbppattern[j],     NULL, 19*i + 0 + j);
              rv34_gen_vlc(rv34_table_intra_secondpat[i][j], OTHERBLK_VLC_SIZE, &intra_vlcs[i].second_pattern[j], NULL, 19*i + 2 + j);
              rv34_gen_vlc(rv34_table_intra_thirdpat [i][j], OTHERBLK_VLC_SIZE, &intra_vlcs[i].third_pattern[j],  NULL, 19*i + 4 + j);
              for(k = 0; k < 4; k++){
                  rv34_gen_vlc(rv34_table_intra_cbp[i][j+k*2],  CBP_VLC_SIZE,   &intra_vlcs[i].cbp[j][k],         rv34_cbp_code, 19*i + 6 + j*4 + k);
              }
          }
          for(j = 0; j < 4; j++){
              rv34_gen_vlc(rv34_table_intra_firstpat[i][j], FIRSTBLK_VLC_SIZE, &intra_vlcs[i].first_pattern[j], NULL, 19*i + 14 + j);
          }
          rv34_gen_vlc(rv34_intra_coeff[i], COEFF_VLC_SIZE, &intra_vlcs[i].coefficient, NULL, 19*i + 18);
      }
  
      for(i = 0; i < NUM_INTER_TABLES; i++){
          rv34_gen_vlc(rv34_inter_cbppat[i], CBPPAT_VLC_SIZE, &inter_vlcs[i].cbppattern[0], NULL, i*12 + 95);
          for(j = 0; j < 4; j++){
              rv34_gen_vlc(rv34_inter_cbp[i][j], CBP_VLC_SIZE, &inter_vlcs[i].cbp[0][j], rv34_cbp_code, i*12 + 96 + j);
          }
          for(j = 0; j < 2; j++){
              rv34_gen_vlc(rv34_table_inter_firstpat [i][j], FIRSTBLK_VLC_SIZE, &inter_vlcs[i].first_pattern[j],  NULL, i*12 + 100 + j);
              rv34_gen_vlc(rv34_table_inter_secondpat[i][j], OTHERBLK_VLC_SIZE, &inter_vlcs[i].second_pattern[j], NULL, i*12 + 102 + j);
              rv34_gen_vlc(rv34_table_inter_thirdpat [i][j], OTHERBLK_VLC_SIZE, &inter_vlcs[i].third_pattern[j],  NULL, i*12 + 104 + j);
          }
          rv34_gen_vlc(rv34_inter_coeff[i], COEFF_VLC_SIZE, &inter_vlcs[i].coefficient, NULL, i*12 + 106);
      }
  }
  
  /** @} */ // vlc group
  
  /**
   * @name RV30/40 4x4 block decoding functions
   * @{
   */
  
  /**
   * Decode coded block pattern.
   */
  static int rv34_decode_cbp(GetBitContext *gb, RV34VLC *vlc, int table)
  {
      int pattern, code, cbp=0;
      int ones;
      static const int cbp_masks[3] = {0x100000, 0x010000, 0x110000};
      static const int shifts[4] = { 0, 2, 8, 10 };
      const int *curshift = shifts;
      int i, t, mask;
  
      code = get_vlc2(gb, vlc->cbppattern[table].table, 9, 2);
      pattern = code & 0xF;
      code >>= 4;
  
      ones = rv34_count_ones[pattern];
  
      for(mask = 8; mask; mask >>= 1, curshift++){
          if(pattern & mask)
              cbp |= get_vlc2(gb, vlc->cbp[table][ones].table, vlc->cbp[table][ones].bits, 1) << curshift[0];
      }
  
      for(i = 0; i < 4; i++){
          t = (modulo_three_table[code] >> (6 - 2*i)) & 3;
          if(t == 1)
              cbp |= cbp_masks[get_bits1(gb)] << i;
          if(t == 2)
              cbp |= cbp_masks[2] << i;
      }
      return cbp;
  }
  
  /**
   * Get one coefficient value from the bitstream and store it.
   */
  static inline void decode_coeff(int16_t *dst, int coef, int esc, GetBitContext *gb, VLC* vlc, int q)
  {
      if(coef){
          if(coef == esc){
              coef = get_vlc2(gb, vlc->table, 9, 2);
              if(coef > 23){
                  coef -= 23;
                  coef = 22 + ((1 << coef) | get_bits(gb, coef));
              }
              coef += esc;
          }
          if(get_bits1(gb))
              coef = -coef;
          *dst = (coef*q + 8) >> 4;
      }
  }
  
  /**
   * Decode 2x2 subblock of coefficients.
   */
  static inline void decode_subblock(int16_t *dst, int code, const int is_block2, GetBitContext *gb, VLC *vlc, int q)
  {
      int flags = modulo_three_table[code];
  
      decode_coeff(    dst+0*4+0, (flags >> 6)    , 3, gb, vlc, q);
      if(is_block2){
          decode_coeff(dst+1*4+0, (flags >> 4) & 3, 2, gb, vlc, q);
          decode_coeff(dst+0*4+1, (flags >> 2) & 3, 2, gb, vlc, q);
      }else{
          decode_coeff(dst+0*4+1, (flags >> 4) & 3, 2, gb, vlc, q);
          decode_coeff(dst+1*4+0, (flags >> 2) & 3, 2, gb, vlc, q);
      }
      decode_coeff(    dst+1*4+1, (flags >> 0) & 3, 2, gb, vlc, q);
  }
  
  /**
   * Decode a single coefficient.
   */
  static inline void decode_subblock1(int16_t *dst, int code, GetBitContext *gb, VLC *vlc, int q)
  {
      int coeff = modulo_three_table[code] >> 6;
      decode_coeff(dst, coeff, 3, gb, vlc, q);
  }
  
  static inline void decode_subblock3(int16_t *dst, int code, GetBitContext *gb, VLC *vlc,
                                      int q_dc, int q_ac1, int q_ac2)
  {
      int flags = modulo_three_table[code];
  
      decode_coeff(dst+0*4+0, (flags >> 6)    , 3, gb, vlc, q_dc);
      decode_coeff(dst+0*4+1, (flags >> 4) & 3, 2, gb, vlc, q_ac1);
      decode_coeff(dst+1*4+0, (flags >> 2) & 3, 2, gb, vlc, q_ac1);
      decode_coeff(dst+1*4+1, (flags >> 0) & 3, 2, gb, vlc, q_ac2);
  }
  
  /**
   * Decode coefficients for 4x4 block.
   *
   * This is done by filling 2x2 subblocks with decoded coefficients
   * in this order (the same for subblocks and subblock coefficients):
   *  o--o
   *    /
   *   /
   *  o--o
   */
  
  static int rv34_decode_block(int16_t *dst, GetBitContext *gb, RV34VLC *rvlc, int fc, int sc, int q_dc, int q_ac1, int q_ac2)
  {
      int code, pattern, has_ac = 1;
  
      code = get_vlc2(gb, rvlc->first_pattern[fc].table, 9, 2);
  
      pattern = code & 0x7;
  
      code >>= 3;
  
      if (modulo_three_table[code] & 0x3F) {
          decode_subblock3(dst, code, gb, &rvlc->coefficient, q_dc, q_ac1, q_ac2);
      } else {
          decode_subblock1(dst, code, gb, &rvlc->coefficient, q_dc);
          if (!pattern)
              return 0;
          has_ac = 0;
      }
  
      if(pattern & 4){
          code = get_vlc2(gb, rvlc->second_pattern[sc].table, 9, 2);
          decode_subblock(dst + 4*0+2, code, 0, gb, &rvlc->coefficient, q_ac2);
      }
      if(pattern & 2){ // Looks like coefficients 1 and 2 are swapped for this block
          code = get_vlc2(gb, rvlc->second_pattern[sc].table, 9, 2);
          decode_subblock(dst + 4*2+0, code, 1, gb, &rvlc->coefficient, q_ac2);
      }
      if(pattern & 1){
          code = get_vlc2(gb, rvlc->third_pattern[sc].table, 9, 2);
          decode_subblock(dst + 4*2+2, code, 0, gb, &rvlc->coefficient, q_ac2);
      }
      return has_ac | pattern;
  }
  
  /**
   * @name RV30/40 bitstream parsing
   * @{
   */
  
  /**
   * Decode starting slice position.
   * @todo Maybe replace with ff_h263_decode_mba() ?
   */
  int ff_rv34_get_start_offset(GetBitContext *gb, int mb_size)
  {
      int i;
      for(i = 0; i < 5; i++)
          if(rv34_mb_max_sizes[i] >= mb_size - 1)
              break;
      return rv34_mb_bits_sizes[i];
  }
  
  /**
   * Select VLC set for decoding from current quantizer, modifier and frame type.
   */
  static inline RV34VLC* choose_vlc_set(int quant, int mod, int type)
  {
      if(mod == 2 && quant < 19) quant += 10;
      else if(mod && quant < 26) quant += 5;
      return type ? &inter_vlcs[rv34_quant_to_vlc_set[1][av_clip(quant, 0, 30)]]
                  : &intra_vlcs[rv34_quant_to_vlc_set[0][av_clip(quant, 0, 30)]];
  }
  
  /**
   * Decode intra macroblock header and return CBP in case of success, -1 otherwise.
   */
  static int rv34_decode_intra_mb_header(RV34DecContext *r, int8_t *intra_types)
  {
      MpegEncContext *s = &r->s;
      GetBitContext *gb = &s->gb;
      int mb_pos = s->mb_x + s->mb_y * s->mb_stride;
      int t;
  
      r->is16 = get_bits1(gb);
      if(r->is16){
          s->current_picture_ptr->mb_type[mb_pos] = MB_TYPE_INTRA16x16;
          r->block_type = RV34_MB_TYPE_INTRA16x16;
          t = get_bits(gb, 2);
          fill_rectangle(intra_types, 4, 4, r->intra_types_stride, t, sizeof(intra_types[0]));
          r->luma_vlc   = 2;
      }else{
          if(!r->rv30){
              if(!get_bits1(gb))
                  av_log(s->avctx, AV_LOG_ERROR, "Need DQUANT\n");
          }
          s->current_picture_ptr->mb_type[mb_pos] = MB_TYPE_INTRA;
          r->block_type = RV34_MB_TYPE_INTRA;
          if(r->decode_intra_types(r, gb, intra_types) < 0)
              return -1;
          r->luma_vlc   = 1;
      }
  
      r->chroma_vlc = 0;
      r->cur_vlcs   = choose_vlc_set(r->si.quant, r->si.vlc_set, 0);
  
      return rv34_decode_cbp(gb, r->cur_vlcs, r->is16);
  }
  
  /**
   * Decode inter macroblock header and return CBP in case of success, -1 otherwise.
   */
  static int rv34_decode_inter_mb_header(RV34DecContext *r, int8_t *intra_types)
  {
      MpegEncContext *s = &r->s;
      GetBitContext *gb = &s->gb;
      int mb_pos = s->mb_x + s->mb_y * s->mb_stride;
      int i, t;
  
      r->block_type = r->decode_mb_info(r);
      if(r->block_type == -1)
          return -1;
      s->current_picture_ptr->mb_type[mb_pos] = rv34_mb_type_to_lavc[r->block_type];
      r->mb_type[mb_pos] = r->block_type;
      if(r->block_type == RV34_MB_SKIP){
          if(s->pict_type == AV_PICTURE_TYPE_P)
              r->mb_type[mb_pos] = RV34_MB_P_16x16;
          if(s->pict_type == AV_PICTURE_TYPE_B)
              r->mb_type[mb_pos] = RV34_MB_B_DIRECT;
      }
      r->is16 = !!IS_INTRA16x16(s->current_picture_ptr->mb_type[mb_pos]);
      if (rv34_decode_mv(r, r->block_type) < 0)
          return -1;
      if(r->block_type == RV34_MB_SKIP){
          fill_rectangle(intra_types, 4, 4, r->intra_types_stride, 0, sizeof(intra_types[0]));
          return 0;
      }
      r->chroma_vlc = 1;
      r->luma_vlc   = 0;
  
      if(IS_INTRA(s->current_picture_ptr->mb_type[mb_pos])){
          if(r->is16){
              t = get_bits(gb, 2);
              fill_rectangle(intra_types, 4, 4, r->intra_types_stride, t, sizeof(intra_types[0]));
              r->luma_vlc   = 2;
          }else{
              if(r->decode_intra_types(r, gb, intra_types) < 0)
                  return -1;
              r->luma_vlc   = 1;
          }
          r->chroma_vlc = 0;
          r->cur_vlcs = choose_vlc_set(r->si.quant, r->si.vlc_set, 0);
      }else{
          for(i = 0; i < 16; i++)
              intra_types[(i & 3) + (i>>2) * r->intra_types_stride] = 0;
          r->cur_vlcs = choose_vlc_set(r->si.quant, r->si.vlc_set, 1);
          if(r->mb_type[mb_pos] == RV34_MB_P_MIX16x16){
              r->is16 = 1;
              r->chroma_vlc = 1;
              r->luma_vlc   = 2;
              r->cur_vlcs = choose_vlc_set(r->si.quant, r->si.vlc_set, 0);
          }
      }
  
      return rv34_decode_cbp(gb, r->cur_vlcs, r->is16);
  }
  
  /** @} */ //bitstream functions
  
  /**
   * @name motion vector related code (prediction, reconstruction, motion compensation)
   * @{
   */
  
  /** macroblock partition width in 8x8 blocks */
  static const uint8_t part_sizes_w[RV34_MB_TYPES] = { 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2 };
  
  /** macroblock partition height in 8x8 blocks */
  static const uint8_t part_sizes_h[RV34_MB_TYPES] = { 2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 2, 2 };
  
  /** availability index for subblocks */
  static const uint8_t avail_indexes[4] = { 6, 7, 10, 11 };
  
  /**
   * motion vector prediction
   *
   * Motion prediction performed for the block by using median prediction of
   * motion vectors from the left, top and right top blocks but in corner cases
   * some other vectors may be used instead.
   */
  static void rv34_pred_mv(RV34DecContext *r, int block_type, int subblock_no, int dmv_no)
  {
      MpegEncContext *s = &r->s;
      int mv_pos = s->mb_x * 2 + s->mb_y * 2 * s->b8_stride;
      int A[2] = {0}, B[2], C[2];
      int i, j;
      int mx, my;
      int* avail = r->avail_cache + avail_indexes[subblock_no];
      int c_off = part_sizes_w[block_type];
  
      mv_pos += (subblock_no & 1) + (subblock_no >> 1)*s->b8_stride;
      if(subblock_no == 3)
          c_off = -1;
  
      if(avail[-1]){
          A[0] = s->current_picture_ptr->motion_val[0][mv_pos-1][0];
          A[1] = s->current_picture_ptr->motion_val[0][mv_pos-1][1];
      }
      if(avail[-4]){
          B[0] = s->current_picture_ptr->motion_val[0][mv_pos-s->b8_stride][0];
          B[1] = s->current_picture_ptr->motion_val[0][mv_pos-s->b8_stride][1];
      }else{
          B[0] = A[0];
          B[1] = A[1];
      }
      if(!avail[c_off-4]){
          if(avail[-4] && (avail[-1] || r->rv30)){
              C[0] = s->current_picture_ptr->motion_val[0][mv_pos-s->b8_stride-1][0];
              C[1] = s->current_picture_ptr->motion_val[0][mv_pos-s->b8_stride-1][1];
          }else{
              C[0] = A[0];
              C[1] = A[1];
          }
      }else{
          C[0] = s->current_picture_ptr->motion_val[0][mv_pos-s->b8_stride+c_off][0];
          C[1] = s->current_picture_ptr->motion_val[0][mv_pos-s->b8_stride+c_off][1];
      }
      mx = mid_pred(A[0], B[0], C[0]);
      my = mid_pred(A[1], B[1], C[1]);
      mx += r->dmv[dmv_no][0];
      my += r->dmv[dmv_no][1];
      for(j = 0; j < part_sizes_h[block_type]; j++){
          for(i = 0; i < part_sizes_w[block_type]; i++){
              s->current_picture_ptr->motion_val[0][mv_pos + i + j*s->b8_stride][0] = mx;
              s->current_picture_ptr->motion_val[0][mv_pos + i + j*s->b8_stride][1] = my;
          }
      }
  }
  
  #define GET_PTS_DIFF(a, b) (((a) - (b) + 8192) & 0x1FFF)
  
  /**
   * Calculate motion vector component that should be added for direct blocks.
   */
  static int calc_add_mv(RV34DecContext *r, int dir, int val)
  {
      int mul = dir ? -r->mv_weight2 : r->mv_weight1;
  
      return (int)(val * (SUINT)mul + 0x2000) >> 14;
  }
  
  /**
   * Predict motion vector for B-frame macroblock.
   */
  static inline void rv34_pred_b_vector(int A[2], int B[2], int C[2],
                                        int A_avail, int B_avail, int C_avail,
                                        int *mx, int *my)
  {
      if(A_avail + B_avail + C_avail != 3){
          *mx = A[0] + B[0] + C[0];
          *my = A[1] + B[1] + C[1];
          if(A_avail + B_avail + C_avail == 2){
              *mx /= 2;
              *my /= 2;
          }
      }else{
          *mx = mid_pred(A[0], B[0], C[0]);
          *my = mid_pred(A[1], B[1], C[1]);
      }
  }
  
  /**
   * motion vector prediction for B-frames
   */
  static void rv34_pred_mv_b(RV34DecContext *r, int block_type, int dir)
  {
      MpegEncContext *s = &r->s;
      int mb_pos = s->mb_x + s->mb_y * s->mb_stride;
      int mv_pos = s->mb_x * 2 + s->mb_y * 2 * s->b8_stride;
      int A[2] = { 0 }, B[2] = { 0 }, C[2] = { 0 };
      int has_A = 0, has_B = 0, has_C = 0;
      int mx, my;
      int i, j;
      Picture *cur_pic = s->current_picture_ptr;
      const int mask = dir ? MB_TYPE_L1 : MB_TYPE_L0;
      int type = cur_pic->mb_type[mb_pos];
  
      if((r->avail_cache[6-1] & type) & mask){
          A[0] = cur_pic->motion_val[dir][mv_pos - 1][0];
          A[1] = cur_pic->motion_val[dir][mv_pos - 1][1];
          has_A = 1;
      }
      if((r->avail_cache[6-4] & type) & mask){
          B[0] = cur_pic->motion_val[dir][mv_pos - s->b8_stride][0];
          B[1] = cur_pic->motion_val[dir][mv_pos - s->b8_stride][1];
          has_B = 1;
      }
      if(r->avail_cache[6-4] && (r->avail_cache[6-2] & type) & mask){
          C[0] = cur_pic->motion_val[dir][mv_pos - s->b8_stride + 2][0];
          C[1] = cur_pic->motion_val[dir][mv_pos - s->b8_stride + 2][1];
          has_C = 1;
      }else if((s->mb_x+1) == s->mb_width && (r->avail_cache[6-5] & type) & mask){
          C[0] = cur_pic->motion_val[dir][mv_pos - s->b8_stride - 1][0];
          C[1] = cur_pic->motion_val[dir][mv_pos - s->b8_stride - 1][1];
          has_C = 1;
      }
  
      rv34_pred_b_vector(A, B, C, has_A, has_B, has_C, &mx, &my);
  
      mx += r->dmv[dir][0];
      my += r->dmv[dir][1];
  
      for(j = 0; j < 2; j++){
          for(i = 0; i < 2; i++){
              cur_pic->motion_val[dir][mv_pos + i + j*s->b8_stride][0] = mx;
              cur_pic->motion_val[dir][mv_pos + i + j*s->b8_stride][1] = my;
          }
      }
      if(block_type == RV34_MB_B_BACKWARD || block_type == RV34_MB_B_FORWARD){
          ZERO8x2(cur_pic->motion_val[!dir][mv_pos], s->b8_stride);
      }
  }
  
  /**
   * motion vector prediction - RV3 version
   */
  static void rv34_pred_mv_rv3(RV34DecContext *r, int block_type, int dir)
  {
      MpegEncContext *s = &r->s;
      int mv_pos = s->mb_x * 2 + s->mb_y * 2 * s->b8_stride;
      int A[2] = {0}, B[2], C[2];
      int i, j, k;
      int mx, my;
      int* avail = r->avail_cache + avail_indexes[0];
  
      if(avail[-1]){
          A[0] = s->current_picture_ptr->motion_val[0][mv_pos - 1][0];
          A[1] = s->current_picture_ptr->motion_val[0][mv_pos - 1][1];
      }
      if(avail[-4]){
          B[0] = s->current_picture_ptr->motion_val[0][mv_pos - s->b8_stride][0];
          B[1] = s->current_picture_ptr->motion_val[0][mv_pos - s->b8_stride][1];
      }else{
          B[0] = A[0];
          B[1] = A[1];
      }
      if(!avail[-4 + 2]){
          if(avail[-4] && (avail[-1])){
              C[0] = s->current_picture_ptr->motion_val[0][mv_pos - s->b8_stride - 1][0];
              C[1] = s->current_picture_ptr->motion_val[0][mv_pos - s->b8_stride - 1][1];
          }else{
              C[0] = A[0];
              C[1] = A[1];
          }
      }else{
          C[0] = s->current_picture_ptr->motion_val[0][mv_pos - s->b8_stride + 2][0];
          C[1] = s->current_picture_ptr->motion_val[0][mv_pos - s->b8_stride + 2][1];
      }
      mx = mid_pred(A[0], B[0], C[0]);
      my = mid_pred(A[1], B[1], C[1]);
      mx += r->dmv[0][0];
      my += r->dmv[0][1];
      for(j = 0; j < 2; j++){
          for(i = 0; i < 2; i++){
              for(k = 0; k < 2; k++){
                  s->current_picture_ptr->motion_val[k][mv_pos + i + j*s->b8_stride][0] = mx;
                  s->current_picture_ptr->motion_val[k][mv_pos + i + j*s->b8_stride][1] = my;
              }
          }
      }
  }
  
  static const int chroma_coeffs[3] = { 0, 3, 5 };
  
  /**
   * generic motion compensation function
   *
   * @param r decoder context
   * @param block_type type of the current block
   * @param xoff horizontal offset from the start of the current block
   * @param yoff vertical offset from the start of the current block
   * @param mv_off offset to the motion vector information
   * @param width width of the current partition in 8x8 blocks
   * @param height height of the current partition in 8x8 blocks
   * @param dir motion compensation direction (i.e. from the last or the next reference frame)
   * @param thirdpel motion vectors are specified in 1/3 of pixel
   * @param qpel_mc a set of functions used to perform luma motion compensation
   * @param chroma_mc a set of functions used to perform chroma motion compensation
   */
  static inline void rv34_mc(RV34DecContext *r, const int block_type,
                            const int xoff, const int yoff, int mv_off,
                            const int width, const int height, int dir,
                            const int thirdpel, int weighted,
                            qpel_mc_func (*qpel_mc)[16],
                            h264_chroma_mc_func (*chroma_mc))
  {
      MpegEncContext *s = &r->s;
      uint8_t *Y, *U, *V, *srcY, *srcU, *srcV;
      int dxy, mx, my, umx, umy, lx, ly, uvmx, uvmy, src_x, src_y, uvsrc_x, uvsrc_y;
      int mv_pos = s->mb_x * 2 + s->mb_y * 2 * s->b8_stride + mv_off;
      int is16x16 = 1;
      int emu = 0;
  
      if(thirdpel){
          int chroma_mx, chroma_my;
          mx = (s->current_picture_ptr->motion_val[dir][mv_pos][0] + (3 << 24)) / 3 - (1 << 24);
          my = (s->current_picture_ptr->motion_val[dir][mv_pos][1] + (3 << 24)) / 3 - (1 << 24);
          lx = (s->current_picture_ptr->motion_val[dir][mv_pos][0] + (3 << 24)) % 3;
          ly = (s->current_picture_ptr->motion_val[dir][mv_pos][1] + (3 << 24)) % 3;
          chroma_mx = s->current_picture_ptr->motion_val[dir][mv_pos][0] / 2;
          chroma_my = s->current_picture_ptr->motion_val[dir][mv_pos][1] / 2;
          umx = (chroma_mx + (3 << 24)) / 3 - (1 << 24);
          umy = (chroma_my + (3 << 24)) / 3 - (1 << 24);
          uvmx = chroma_coeffs[(chroma_mx + (3 << 24)) % 3];
          uvmy = chroma_coeffs[(chroma_my + (3 << 24)) % 3];
      }else{
          int cx, cy;
          mx = s->current_picture_ptr->motion_val[dir][mv_pos][0] >> 2;
          my = s->current_picture_ptr->motion_val[dir][mv_pos][1] >> 2;
          lx = s->current_picture_ptr->motion_val[dir][mv_pos][0] & 3;
          ly = s->current_picture_ptr->motion_val[dir][mv_pos][1] & 3;
          cx = s->current_picture_ptr->motion_val[dir][mv_pos][0] / 2;
          cy = s->current_picture_ptr->motion_val[dir][mv_pos][1] / 2;
          umx = cx >> 2;
          umy = cy >> 2;
          uvmx = (cx & 3) << 1;
          uvmy = (cy & 3) << 1;
          //due to some flaw RV40 uses the same MC compensation routine for H2V2 and H3V3
          if(uvmx == 6 && uvmy == 6)
              uvmx = uvmy = 4;
      }
  
      if (HAVE_THREADS && (s->avctx->active_thread_type & FF_THREAD_FRAME)) {
          /* wait for the referenced mb row to be finished */
          int mb_row = s->mb_y + ((yoff + my + 5 + 8 * height) >> 4);
          ThreadFrame *f = dir ? &s->next_picture_ptr->tf : &s->last_picture_ptr->tf;
          ff_thread_await_progress(f, mb_row, 0);
      }
  
      dxy = ly*4 + lx;
      srcY = dir ? s->next_picture_ptr->f->data[0] : s->last_picture_ptr->f->data[0];
      srcU = dir ? s->next_picture_ptr->f->data[1] : s->last_picture_ptr->f->data[1];
      srcV = dir ? s->next_picture_ptr->f->data[2] : s->last_picture_ptr->f->data[2];
      src_x = s->mb_x * 16 + xoff + mx;
      src_y = s->mb_y * 16 + yoff + my;
      uvsrc_x = s->mb_x * 8 + (xoff >> 1) + umx;
      uvsrc_y = s->mb_y * 8 + (yoff >> 1) + umy;
      srcY += src_y * s->linesize + src_x;
      srcU += uvsrc_y * s->uvlinesize + uvsrc_x;
      srcV += uvsrc_y * s->uvlinesize + uvsrc_x;
      if(s->h_edge_pos - (width << 3) < 6 || s->v_edge_pos - (height << 3) < 6 ||
         (unsigned)(src_x - !!lx*2) > s->h_edge_pos - !!lx*2 - (width <<3) - 4 ||
         (unsigned)(src_y - !!ly*2) > s->v_edge_pos - !!ly*2 - (height<<3) - 4) {
          srcY -= 2 + 2*s->linesize;
          s->vdsp.emulated_edge_mc(s->sc.edge_emu_buffer, srcY,
                                   s->linesize, s->linesize,
                                   (width << 3) + 6, (height << 3) + 6,
                                   src_x - 2, src_y - 2,
                                   s->h_edge_pos, s->v_edge_pos);
          srcY = s->sc.edge_emu_buffer + 2 + 2*s->linesize;
          emu = 1;
      }
      if(!weighted){
          Y = s->dest[0] + xoff      + yoff     *s->linesize;
          U = s->dest[1] + (xoff>>1) + (yoff>>1)*s->uvlinesize;
          V = s->dest[2] + (xoff>>1) + (yoff>>1)*s->uvlinesize;
      }else{
          Y = r->tmp_b_block_y [dir]     +  xoff     +  yoff    *s->linesize;
          U = r->tmp_b_block_uv[dir*2]   + (xoff>>1) + (yoff>>1)*s->uvlinesize;
          V = r->tmp_b_block_uv[dir*2+1] + (xoff>>1) + (yoff>>1)*s->uvlinesize;
      }
  
      if(block_type == RV34_MB_P_16x8){
          qpel_mc[1][dxy](Y, srcY, s->linesize);
          Y    += 8;
          srcY += 8;
      }else if(block_type == RV34_MB_P_8x16){
          qpel_mc[1][dxy](Y, srcY, s->linesize);
          Y    += 8 * s->linesize;
          srcY += 8 * s->linesize;
      }
      is16x16 = (block_type != RV34_MB_P_8x8) && (block_type != RV34_MB_P_16x8) && (block_type != RV34_MB_P_8x16);
      qpel_mc[!is16x16][dxy](Y, srcY, s->linesize);
      if (emu) {
          uint8_t *uvbuf = s->sc.edge_emu_buffer;
  
          s->vdsp.emulated_edge_mc(uvbuf, srcU,
                                   s->uvlinesize, s->uvlinesize,
                                   (width << 2) + 1, (height << 2) + 1,
                                   uvsrc_x, uvsrc_y,
                                   s->h_edge_pos >> 1, s->v_edge_pos >> 1);
          srcU = uvbuf;
          uvbuf += 9*s->uvlinesize;
  
          s->vdsp.emulated_edge_mc(uvbuf, srcV,
                                   s->uvlinesize, s->uvlinesize,
                                   (width << 2) + 1, (height << 2) + 1,
                                   uvsrc_x, uvsrc_y,
                                   s->h_edge_pos >> 1, s->v_edge_pos >> 1);
          srcV = uvbuf;
      }
      chroma_mc[2-width]   (U, srcU, s->uvlinesize, height*4, uvmx, uvmy);
      chroma_mc[2-width]   (V, srcV, s->uvlinesize, height*4, uvmx, uvmy);
  }
  
  static void rv34_mc_1mv(RV34DecContext *r, const int block_type,
                          const int xoff, const int yoff, int mv_off,
                          const int width, const int height, int dir)
  {
      rv34_mc(r, block_type, xoff, yoff, mv_off, width, height, dir, r->rv30, 0,
              r->rdsp.put_pixels_tab,
              r->rdsp.put_chroma_pixels_tab);
  }
  
  static void rv4_weight(RV34DecContext *r)
  {
      r->rdsp.rv40_weight_pixels_tab[r->scaled_weight][0](r->s.dest[0],
                                                          r->tmp_b_block_y[0],
                                                          r->tmp_b_block_y[1],
                                                          r->weight1,
                                                          r->weight2,
                                                          r->s.linesize);
      r->rdsp.rv40_weight_pixels_tab[r->scaled_weight][1](r->s.dest[1],
                                                          r->tmp_b_block_uv[0],
                                                          r->tmp_b_block_uv[2],
                                                          r->weight1,
                                                          r->weight2,
                                                          r->s.uvlinesize);
      r->rdsp.rv40_weight_pixels_tab[r->scaled_weight][1](r->s.dest[2],
                                                          r->tmp_b_block_uv[1],
                                                          r->tmp_b_block_uv[3],
                                                          r->weight1,
                                                          r->weight2,
                                                          r->s.uvlinesize);
  }
  
  static void rv34_mc_2mv(RV34DecContext *r, const int block_type)
  {
      int weighted = !r->rv30 && block_type != RV34_MB_B_BIDIR && r->weight1 != 8192;
  
      rv34_mc(r, block_type, 0, 0, 0, 2, 2, 0, r->rv30, weighted,
              r->rdsp.put_pixels_tab,
              r->rdsp.put_chroma_pixels_tab);
      if(!weighted){
          rv34_mc(r, block_type, 0, 0, 0, 2, 2, 1, r->rv30, 0,
                  r->rdsp.avg_pixels_tab,
                  r->rdsp.avg_chroma_pixels_tab);
      }else{
          rv34_mc(r, block_type, 0, 0, 0, 2, 2, 1, r->rv30, 1,
                  r->rdsp.put_pixels_tab,
                  r->rdsp.put_chroma_pixels_tab);
          rv4_weight(r);
      }
  }
  
  static void rv34_mc_2mv_skip(RV34DecContext *r)
  {
      int i, j;
      int weighted = !r->rv30 && r->weight1 != 8192;
  
      for(j = 0; j < 2; j++)
          for(i = 0; i < 2; i++){
               rv34_mc(r, RV34_MB_P_8x8, i*8, j*8, i+j*r->s.b8_stride, 1, 1, 0, r->rv30,
                       weighted,
                       r->rdsp.put_pixels_tab,
                       r->rdsp.put_chroma_pixels_tab);
               rv34_mc(r, RV34_MB_P_8x8, i*8, j*8, i+j*r->s.b8_stride, 1, 1, 1, r->rv30,
                       weighted,
                       weighted ? r->rdsp.put_pixels_tab : r->rdsp.avg_pixels_tab,
                       weighted ? r->rdsp.put_chroma_pixels_tab : r->rdsp.avg_chroma_pixels_tab);
          }
      if(weighted)
          rv4_weight(r);
  }
  
  /** number of motion vectors in each macroblock type */
  static const int num_mvs[RV34_MB_TYPES] = { 0, 0, 1, 4, 1, 1, 0, 0, 2, 2, 2, 1 };
  
  /**
   * Decode motion vector differences
   * and perform motion vector reconstruction and motion compensation.
   */
  static int rv34_decode_mv(RV34DecContext *r, int block_type)
  {
      MpegEncContext *s = &r->s;
      GetBitContext *gb = &s->gb;
      int i, j, k, l;
      int mv_pos = s->mb_x * 2 + s->mb_y * 2 * s->b8_stride;
      int next_bt;
  
      memset(r->dmv, 0, sizeof(r->dmv));
      for(i = 0; i < num_mvs[block_type]; i++){
          r->dmv[i][0] = get_interleaved_se_golomb(gb);
          r->dmv[i][1] = get_interleaved_se_golomb(gb);
          if (r->dmv[i][0] == INVALID_VLC ||
              r->dmv[i][1] == INVALID_VLC) {
              r->dmv[i][0] = r->dmv[i][1] = 0;
              return AVERROR_INVALIDDATA;
          }
      }
      switch(block_type){
      case RV34_MB_TYPE_INTRA:
      case RV34_MB_TYPE_INTRA16x16:
          ZERO8x2(s->current_picture_ptr->motion_val[0][s->mb_x * 2 + s->mb_y * 2 * s->b8_stride], s->b8_stride);
          return 0;
      case RV34_MB_SKIP:
          if(s->pict_type == AV_PICTURE_TYPE_P){
              ZERO8x2(s->current_picture_ptr->motion_val[0][s->mb_x * 2 + s->mb_y * 2 * s->b8_stride], s->b8_stride);
              rv34_mc_1mv (r, block_type, 0, 0, 0, 2, 2, 0);
              break;
          }
      case RV34_MB_B_DIRECT:
          //surprisingly, it uses motion scheme from next reference frame
          /* wait for the current mb row to be finished */
          if (HAVE_THREADS && (s->avctx->active_thread_type & FF_THREAD_FRAME))
              ff_thread_await_progress(&s->next_picture_ptr->tf, FFMAX(0, s->mb_y-1), 0);
  
          next_bt = s->next_picture_ptr->mb_type[s->mb_x + s->mb_y * s->mb_stride];
          if(IS_INTRA(next_bt) || IS_SKIP(next_bt)){
              ZERO8x2(s->current_picture_ptr->motion_val[0][s->mb_x * 2 + s->mb_y * 2 * s->b8_stride], s->b8_stride);
              ZERO8x2(s->current_picture_ptr->motion_val[1][s->mb_x * 2 + s->mb_y * 2 * s->b8_stride], s->b8_stride);
          }else
              for(j = 0; j < 2; j++)
                  for(i = 0; i < 2; i++)
                      for(k = 0; k < 2; k++)
                          for(l = 0; l < 2; l++)
                              s->current_picture_ptr->motion_val[l][mv_pos + i + j*s->b8_stride][k] = calc_add_mv(r, l, s->next_picture_ptr->motion_val[0][mv_pos + i + j*s->b8_stride][k]);
          if(!(IS_16X8(next_bt) || IS_8X16(next_bt) || IS_8X8(next_bt))) //we can use whole macroblock MC
              rv34_mc_2mv(r, block_type);
          else
              rv34_mc_2mv_skip(r);
          ZERO8x2(s->current_picture_ptr->motion_val[0][s->mb_x * 2 + s->mb_y * 2 * s->b8_stride], s->b8_stride);
          break;
      case RV34_MB_P_16x16:
      case RV34_MB_P_MIX16x16:
          rv34_pred_mv(r, block_type, 0, 0);
          rv34_mc_1mv (r, block_type, 0, 0, 0, 2, 2, 0);
          break;
      case RV34_MB_B_FORWARD:
      case RV34_MB_B_BACKWARD:
          r->dmv[1][0] = r->dmv[0][0];
          r->dmv[1][1] = r->dmv[0][1];
          if(r->rv30)
              rv34_pred_mv_rv3(r, block_type, block_type == RV34_MB_B_BACKWARD);
          else
              rv34_pred_mv_b  (r, block_type, block_type == RV34_MB_B_BACKWARD);
          rv34_mc_1mv     (r, block_type, 0, 0, 0, 2, 2, block_type == RV34_MB_B_BACKWARD);
          break;
      case RV34_MB_P_16x8:
      case RV34_MB_P_8x16:
          rv34_pred_mv(r, block_type, 0, 0);
          rv34_pred_mv(r, block_type, 1 + (block_type == RV34_MB_P_16x8), 1);
          if(block_type == RV34_MB_P_16x8){
              rv34_mc_1mv(r, block_type, 0, 0, 0,            2, 1, 0);
              rv34_mc_1mv(r, block_type, 0, 8, s->b8_stride, 2, 1, 0);
          }
          if(block_type == RV34_MB_P_8x16){
              rv34_mc_1mv(r, block_type, 0, 0, 0, 1, 2, 0);
              rv34_mc_1mv(r, block_type, 8, 0, 1, 1, 2, 0);
          }
          break;
      case RV34_MB_B_BIDIR:
          rv34_pred_mv_b  (r, block_type, 0);
          rv34_pred_mv_b  (r, block_type, 1);
          rv34_mc_2mv     (r, block_type);
          break;
      case RV34_MB_P_8x8:
          for(i=0;i< 4;i++){
              rv34_pred_mv(r, block_type, i, i);
              rv34_mc_1mv (r, block_type, (i&1)<<3, (i&2)<<2, (i&1)+(i>>1)*s->b8_stride, 1, 1, 0);
          }
          break;
      }
  
      return 0;
  }
  /** @} */ // mv group
  
  /**
   * @name Macroblock reconstruction functions
   * @{
   */
  /** mapping of RV30/40 intra prediction types to standard H.264 types */
  static const int ittrans[9] = {
   DC_PRED, VERT_PRED, HOR_PRED, DIAG_DOWN_RIGHT_PRED, DIAG_DOWN_LEFT_PRED,
   VERT_RIGHT_PRED, VERT_LEFT_PRED, HOR_UP_PRED, HOR_DOWN_PRED,
  };
  
  /** mapping of RV30/40 intra 16x16 prediction types to standard H.264 types */
  static const int ittrans16[4] = {
   DC_PRED8x8, VERT_PRED8x8, HOR_PRED8x8, PLANE_PRED8x8,
  };
  
  /**
   * Perform 4x4 intra prediction.
   */
  static void rv34_pred_4x4_block(RV34DecContext *r, uint8_t *dst, int stride, int itype, int up, int left, int down, int right)
  {
      uint8_t *prev = dst - stride + 4;
      uint32_t topleft;
  
      if(!up && !left)
          itype = DC_128_PRED;
      else if(!up){
          if(itype == VERT_PRED) itype = HOR_PRED;
          if(itype == DC_PRED)   itype = LEFT_DC_PRED;
      }else if(!left){
          if(itype == HOR_PRED)  itype = VERT_PRED;
          if(itype == DC_PRED)   itype = TOP_DC_PRED;
          if(itype == DIAG_DOWN_LEFT_PRED) itype = DIAG_DOWN_LEFT_PRED_RV40_NODOWN;
      }
      if(!down){
          if(itype == DIAG_DOWN_LEFT_PRED) itype = DIAG_DOWN_LEFT_PRED_RV40_NODOWN;
          if(itype == HOR_UP_PRED) itype = HOR_UP_PRED_RV40_NODOWN;
          if(itype == VERT_LEFT_PRED) itype = VERT_LEFT_PRED_RV40_NODOWN;
      }
      if(!right && up){
          topleft = dst[-stride + 3] * 0x01010101u;
          prev = (uint8_t*)&topleft;
      }
      r->h.pred4x4[itype](dst, prev, stride);
  }
  
  static inline int adjust_pred16(int itype, int up, int left)
  {
      if(!up && !left)
          itype = DC_128_PRED8x8;
      else if(!up){
          if(itype == PLANE_PRED8x8)itype = HOR_PRED8x8;
          if(itype == VERT_PRED8x8) itype = HOR_PRED8x8;
          if(itype == DC_PRED8x8)   itype = LEFT_DC_PRED8x8;
      }else if(!left){
          if(itype == PLANE_PRED8x8)itype = VERT_PRED8x8;
          if(itype == HOR_PRED8x8)  itype = VERT_PRED8x8;
          if(itype == DC_PRED8x8)   itype = TOP_DC_PRED8x8;
      }
      return itype;
  }
  
  static inline void rv34_process_block(RV34DecContext *r,
                                        uint8_t *pdst, int stride,
                                        int fc, int sc, int q_dc, int q_ac)
  {
      MpegEncContext *s = &r->s;
      int16_t *ptr = s->block[0];
      int has_ac = rv34_decode_block(ptr, &s->gb, r->cur_vlcs,
                                     fc, sc, q_dc, q_ac, q_ac);
      if(has_ac){
          r->rdsp.rv34_idct_add(pdst, stride, ptr);
      }else{
          r->rdsp.rv34_idct_dc_add(pdst, stride, ptr[0]);
          ptr[0] = 0;
      }
  }
  
  static void rv34_output_i16x16(RV34DecContext *r, int8_t *intra_types, int cbp)
  {
      LOCAL_ALIGNED_16(int16_t, block16, [16]);
      MpegEncContext *s    = &r->s;
      GetBitContext  *gb   = &s->gb;
      int             q_dc = rv34_qscale_tab[ r->luma_dc_quant_i[s->qscale] ],
                      q_ac = rv34_qscale_tab[s->qscale];
      uint8_t        *dst  = s->dest[0];
      int16_t        *ptr  = s->block[0];
      int i, j, itype, has_ac;
  
      memset(block16, 0, 16 * sizeof(*block16));
  
      has_ac = rv34_decode_block(block16, gb, r->cur_vlcs, 3, 0, q_dc, q_dc, q_ac);
      if(has_ac)
          r->rdsp.rv34_inv_transform(block16);
      else
          r->rdsp.rv34_inv_transform_dc(block16);
  
      itype = ittrans16[intra_types[0]];
      itype = adjust_pred16(itype, r->avail_cache[6-4], r->avail_cache[6-1]);
      r->h.pred16x16[itype](dst, s->linesize);
  
      for(j = 0; j < 4; j++){
          for(i = 0; i < 4; i++, cbp >>= 1){
              int dc = block16[i + j*4];
  
              if(cbp & 1){
                  has_ac = rv34_decode_block(ptr, gb, r->cur_vlcs, r->luma_vlc, 0, q_ac, q_ac, q_ac);
              }else
                  has_ac = 0;
  
              if(has_ac){
                  ptr[0] = dc;
                  r->rdsp.rv34_idct_add(dst+4*i, s->linesize, ptr);
              }else
                  r->rdsp.rv34_idct_dc_add(dst+4*i, s->linesize, dc);
          }
  
          dst += 4*s->linesize;
      }
  
      itype = ittrans16[intra_types[0]];
      if(itype == PLANE_PRED8x8) itype = DC_PRED8x8;
      itype = adjust_pred16(itype, r->avail_cache[6-4], r->avail_cache[6-1]);
  
      q_dc = rv34_qscale_tab[rv34_chroma_quant[1][s->qscale]];
      q_ac = rv34_qscale_tab[rv34_chroma_quant[0][s->qscale]];
  
      for(j = 1; j < 3; j++){
          dst = s->dest[j];
          r->h.pred8x8[itype](dst, s->uvlinesize);
          for(i = 0; i < 4; i++, cbp >>= 1){
              uint8_t *pdst;
              if(!(cbp & 1)) continue;
              pdst   = dst + (i&1)*4 + (i&2)*2*s->uvlinesize;
  
              rv34_process_block(r, pdst, s->uvlinesize,
                                 r->chroma_vlc, 1, q_dc, q_ac);
          }
      }
  }
  
  static void rv34_output_intra(RV34DecContext *r, int8_t *intra_types, int cbp)
  {
      MpegEncContext *s   = &r->s;
      uint8_t        *dst = s->dest[0];
      int      avail[6*8] = {0};
      int i, j, k;
      int idx, q_ac, q_dc;
  
      // Set neighbour information.
      if(r->avail_cache[1])
          avail[0] = 1;
      if(r->avail_cache[2])
          avail[1] = avail[2] = 1;
      if(r->avail_cache[3])
          avail[3] = avail[4] = 1;
      if(r->avail_cache[4])
          avail[5] = 1;
      if(r->avail_cache[5])
          avail[8] = avail[16] = 1;
      if(r->avail_cache[9])
          avail[24] = avail[32] = 1;
  
      q_ac = rv34_qscale_tab[s->qscale];
      for(j = 0; j < 4; j++){
          idx = 9 + j*8;
          for(i = 0; i < 4; i++, cbp >>= 1, dst += 4, idx++){
              rv34_pred_4x4_block(r, dst, s->linesize, ittrans[intra_types[i]], avail[idx-8], avail[idx-1], avail[idx+7], avail[idx-7]);
              avail[idx] = 1;
              if(!(cbp & 1)) continue;
  
              rv34_process_block(r, dst, s->linesize,
                                 r->luma_vlc, 0, q_ac, q_ac);
          }
          dst += s->linesize * 4 - 4*4;
          intra_types += r->intra_types_stride;
      }
  
      intra_types -= r->intra_types_stride * 4;
  
      q_dc = rv34_qscale_tab[rv34_chroma_quant[1][s->qscale]];
      q_ac = rv34_qscale_tab[rv34_chroma_quant[0][s->qscale]];
  
      for(k = 0; k < 2; k++){
          dst = s->dest[1+k];
          fill_rectangle(r->avail_cache + 6, 2, 2, 4, 0, 4);
  
          for(j = 0; j < 2; j++){
              int* acache = r->avail_cache + 6 + j*4;
              for(i = 0; i < 2; i++, cbp >>= 1, acache++){
                  int itype = ittrans[intra_types[i*2+j*2*r->intra_types_stride]];
                  rv34_pred_4x4_block(r, dst+4*i, s->uvlinesize, itype, acache[-4], acache[-1], !i && !j, acache[-3]);
                  acache[0] = 1;
  
                  if(!(cbp&1)) continue;
  
                  rv34_process_block(r, dst + 4*i, s->uvlinesize,
                                     r->chroma_vlc, 1, q_dc, q_ac);
              }
  
              dst += 4*s->uvlinesize;
          }
      }
  }
  
  static int is_mv_diff_gt_3(int16_t (*motion_val)[2], int step)
  {
      int d;
      d = motion_val[0][0] - motion_val[-step][0];
      if(d < -3 || d > 3)
          return 1;
      d = motion_val[0][1] - motion_val[-step][1];
      if(d < -3 || d > 3)
          return 1;
      return 0;
  }
  
  static int rv34_set_deblock_coef(RV34DecContext *r)
  {
      MpegEncContext *s = &r->s;
      int hmvmask = 0, vmvmask = 0, i, j;
      int midx = s->mb_x * 2 + s->mb_y * 2 * s->b8_stride;
      int16_t (*motion_val)[2] = &s->current_picture_ptr->motion_val[0][midx];
      for(j = 0; j < 16; j += 8){
          for(i = 0; i < 2; i++){
              if(is_mv_diff_gt_3(motion_val + i, 1))
                  vmvmask |= 0x11 << (j + i*2);
              if((j || s->mb_y) && is_mv_diff_gt_3(motion_val + i, s->b8_stride))
                  hmvmask |= 0x03 << (j + i*2);
          }
          motion_val += s->b8_stride;
      }
      if(s->first_slice_line)
          hmvmask &= ~0x000F;
      if(!s->mb_x)
          vmvmask &= ~0x1111;
      if(r->rv30){ //RV30 marks both subblocks on the edge for filtering
          vmvmask |= (vmvmask & 0x4444) >> 1;
          hmvmask |= (hmvmask & 0x0F00) >> 4;
          if(s->mb_x)
              r->deblock_coefs[s->mb_x - 1 + s->mb_y*s->mb_stride] |= (vmvmask & 0x1111) << 3;
          if(!s->first_slice_line)
              r->deblock_coefs[s->mb_x + (s->mb_y - 1)*s->mb_stride] |= (hmvmask & 0xF) << 12;
      }
      return hmvmask | vmvmask;
  }
  
  static int rv34_decode_inter_macroblock(RV34DecContext *r, int8_t *intra_types)
  {
      MpegEncContext *s   = &r->s;
      GetBitContext  *gb  = &s->gb;
      uint8_t        *dst = s->dest[0];
      int16_t        *ptr = s->block[0];
      int          mb_pos = s->mb_x + s->mb_y * s->mb_stride;
      int cbp, cbp2;
      int q_dc, q_ac, has_ac;
      int i, j;
      int dist;
  
      // Calculate which neighbours are available. Maybe it's worth optimizing too.
      memset(r->avail_cache, 0, sizeof(r->avail_cache));
      fill_rectangle(r->avail_cache + 6, 2, 2, 4, 1, 4);
      dist = (s->mb_x - s->resync_mb_x) + (s->mb_y - s->resync_mb_y) * s->mb_width;
      if(s->mb_x && dist)
          r->avail_cache[5] =
          r->avail_cache[9] = s->current_picture_ptr->mb_type[mb_pos - 1];
      if(dist >= s->mb_width)
          r->avail_cache[2] =
          r->avail_cache[3] = s->current_picture_ptr->mb_type[mb_pos - s->mb_stride];
      if(((s->mb_x+1) < s->mb_width) && dist >= s->mb_width - 1)
          r->avail_cache[4] = s->current_picture_ptr->mb_type[mb_pos - s->mb_stride + 1];
      if(s->mb_x && dist > s->mb_width)
          r->avail_cache[1] = s->current_picture_ptr->mb_type[mb_pos - s->mb_stride - 1];
  
      s->qscale = r->si.quant;
      cbp = cbp2 = rv34_decode_inter_mb_header(r, intra_types);
      r->cbp_luma  [mb_pos] = cbp;
      r->cbp_chroma[mb_pos] = cbp >> 16;
      r->deblock_coefs[mb_pos] = rv34_set_deblock_coef(r) | r->cbp_luma[mb_pos];
      s->current_picture_ptr->qscale_table[mb_pos] = s->qscale;
  
      if(cbp == -1)
          return -1;
  
      if (IS_INTRA(s->current_picture_ptr->mb_type[mb_pos])){
          if(r->is16) rv34_output_i16x16(r, intra_types, cbp);
          else        rv34_output_intra(r, intra_types, cbp);
          return 0;
      }
  
      if(r->is16){
          // Only for RV34_MB_P_MIX16x16
          LOCAL_ALIGNED_16(int16_t, block16, [16]);
          memset(block16, 0, 16 * sizeof(*block16));
          q_dc = rv34_qscale_tab[ r->luma_dc_quant_p[s->qscale] ];
          q_ac = rv34_qscale_tab[s->qscale];
          if (rv34_decode_block(block16, gb, r->cur_vlcs, 3, 0, q_dc, q_dc, q_ac))
              r->rdsp.rv34_inv_transform(block16);
          else
              r->rdsp.rv34_inv_transform_dc(block16);
  
          q_ac = rv34_qscale_tab[s->qscale];
  
          for(j = 0; j < 4; j++){
              for(i = 0; i < 4; i++, cbp >>= 1){
                  int      dc   = block16[i + j*4];
  
                  if(cbp & 1){
                      has_ac = rv34_decode_block(ptr, gb, r->cur_vlcs, r->luma_vlc, 0, q_ac, q_ac, q_ac);
                  }else
                      has_ac = 0;
  
                  if(has_ac){
                      ptr[0] = dc;
                      r->rdsp.rv34_idct_add(dst+4*i, s->linesize, ptr);
                  }else
                      r->rdsp.rv34_idct_dc_add(dst+4*i, s->linesize, dc);
              }
  
              dst += 4*s->linesize;
          }
  
          r->cur_vlcs = choose_vlc_set(r->si.quant, r->si.vlc_set, 1);
      }else{
          q_ac = rv34_qscale_tab[s->qscale];
  
          for(j = 0; j < 4; j++){
              for(i = 0; i < 4; i++, cbp >>= 1){
                  if(!(cbp & 1)) continue;
  
                  rv34_process_block(r, dst + 4*i, s->linesize,
                                     r->luma_vlc, 0, q_ac, q_ac);
              }
              dst += 4*s->linesize;
          }
      }
  
      q_dc = rv34_qscale_tab[rv34_chroma_quant[1][s->qscale]];
      q_ac = rv34_qscale_tab[rv34_chroma_quant[0][s->qscale]];
  
      for(j = 1; j < 3; j++){
          dst = s->dest[j];
          for(i = 0; i < 4; i++, cbp >>= 1){
              uint8_t *pdst;
              if(!(cbp & 1)) continue;
              pdst = dst + (i&1)*4 + (i&2)*2*s->uvlinesize;
  
              rv34_process_block(r, pdst, s->uvlinesize,
                                 r->chroma_vlc, 1, q_dc, q_ac);
          }
      }
  
      return 0;
  }
  
  static int rv34_decode_intra_macroblock(RV34DecContext *r, int8_t *intra_types)
  {
      MpegEncContext *s = &r->s;
      int cbp, dist;
      int mb_pos = s->mb_x + s->mb_y * s->mb_stride;
  
      // Calculate which neighbours are available. Maybe it's worth optimizing too.
      memset(r->avail_cache, 0, sizeof(r->avail_cache));
      fill_rectangle(r->avail_cache + 6, 2, 2, 4, 1, 4);
      dist = (s->mb_x - s->resync_mb_x) + (s->mb_y - s->resync_mb_y) * s->mb_width;
      if(s->mb_x && dist)
          r->avail_cache[5] =
          r->avail_cache[9] = s->current_picture_ptr->mb_type[mb_pos - 1];
      if(dist >= s->mb_width)
          r->avail_cache[2] =
          r->avail_cache[3] = s->current_picture_ptr->mb_type[mb_pos - s->mb_stride];
      if(((s->mb_x+1) < s->mb_width) && dist >= s->mb_width - 1)
          r->avail_cache[4] = s->current_picture_ptr->mb_type[mb_pos - s->mb_stride + 1];
      if(s->mb_x && dist > s->mb_width)
          r->avail_cache[1] = s->current_picture_ptr->mb_type[mb_pos - s->mb_stride - 1];
  
      s->qscale = r->si.quant;
      cbp = rv34_decode_intra_mb_header(r, intra_types);
      r->cbp_luma  [mb_pos] = cbp;
      r->cbp_chroma[mb_pos] = cbp >> 16;
      r->deblock_coefs[mb_pos] = 0xFFFF;
      s->current_picture_ptr->qscale_table[mb_pos] = s->qscale;
  
      if(cbp == -1)
          return -1;
  
      if(r->is16){
          rv34_output_i16x16(r, intra_types, cbp);
          return 0;
      }
  
      rv34_output_intra(r, intra_types, cbp);
      return 0;
  }
  
  static int check_slice_end(RV34DecContext *r, MpegEncContext *s)
  {
      int bits;
      if(s->mb_y >= s->mb_height)
          return 1;
      if(!s->mb_num_left)
          return 1;
      if(r->s.mb_skip_run > 1)
          return 0;
      bits = get_bits_left(&s->gb);
      if(bits <= 0 || (bits < 8 && !show_bits(&s->gb, bits)))
          return 1;
      return 0;
  }
  
  
  static void rv34_decoder_free(RV34DecContext *r)
  {
      av_freep(&r->intra_types_hist);
      r->intra_types = NULL;
      av_freep(&r->tmp_b_block_base);
      av_freep(&r->mb_type);
      av_freep(&r->cbp_luma);
      av_freep(&r->cbp_chroma);
      av_freep(&r->deblock_coefs);
  }
  
  
  static int rv34_decoder_alloc(RV34DecContext *r)
  {
      r->intra_types_stride = r->s.mb_width * 4 + 4;
  
      r->cbp_chroma       = av_mallocz(r->s.mb_stride * r->s.mb_height *
                                      sizeof(*r->cbp_chroma));
      r->cbp_luma         = av_mallocz(r->s.mb_stride * r->s.mb_height *
                                      sizeof(*r->cbp_luma));
      r->deblock_coefs    = av_mallocz(r->s.mb_stride * r->s.mb_height *
                                      sizeof(*r->deblock_coefs));
      r->intra_types_hist = av_malloc(r->intra_types_stride * 4 * 2 *
                                      sizeof(*r->intra_types_hist));
      r->mb_type          = av_mallocz(r->s.mb_stride * r->s.mb_height *
                                       sizeof(*r->mb_type));
  
      if (!(r->cbp_chroma       && r->cbp_luma && r->deblock_coefs &&
            r->intra_types_hist && r->mb_type)) {
          rv34_decoder_free(r);
          return AVERROR(ENOMEM);
      }
  
      r->intra_types = r->intra_types_hist + r->intra_types_stride * 4;
  
      return 0;
  }
  
  
  static int rv34_decoder_realloc(RV34DecContext *r)
  {
      rv34_decoder_free(r);
      return rv34_decoder_alloc(r);
  }
  
  
  static int rv34_decode_slice(RV34DecContext *r, int end, const uint8_t* buf, int buf_size)
  {
      MpegEncContext *s = &r->s;
      GetBitContext *gb = &s->gb;
      int mb_pos, slice_type;
      int res;
  
      init_get_bits(&r->s.gb, buf, buf_size*8);
      res = r->parse_slice_header(r, gb, &r->si);
      if(res < 0){
          av_log(s->avctx, AV_LOG_ERROR, "Incorrect or unknown slice header\n");
          return -1;
      }
  
      slice_type = r->si.type ? r->si.type : AV_PICTURE_TYPE_I;
      if (slice_type != s->pict_type) {
          av_log(s->avctx, AV_LOG_ERROR, "Slice type mismatch\n");
          return AVERROR_INVALIDDATA;
      }
      if (s->width != r->si.width || s->height != r->si.height) {
          av_log(s->avctx, AV_LOG_ERROR, "Size mismatch\n");
          return AVERROR_INVALIDDATA;
      }
  
      r->si.end = end;
      s->qscale = r->si.quant;
      s->mb_num_left = r->si.end - r->si.start;
      r->s.mb_skip_run = 0;
  
      mb_pos = s->mb_x + s->mb_y * s->mb_width;
      if(r->si.start != mb_pos){
          av_log(s->avctx, AV_LOG_ERROR, "Slice indicates MB offset %d, got %d\n", r->si.start, mb_pos);
          s->mb_x = r->si.start % s->mb_width;
          s->mb_y = r->si.start / s->mb_width;
      }
      memset(r->intra_types_hist, -1, r->intra_types_stride * 4 * 2 * sizeof(*r->intra_types_hist));
      s->first_slice_line = 1;
      s->resync_mb_x = s->mb_x;
      s->resync_mb_y = s->mb_y;
  
      ff_init_block_index(s);
      while(!check_slice_end(r, s)) {
          ff_update_block_index(s);
  
          if(r->si.type)
              res = rv34_decode_inter_macroblock(r, r->intra_types + s->mb_x * 4 + 4);
          else
              res = rv34_decode_intra_macroblock(r, r->intra_types + s->mb_x * 4 + 4);
          if(res < 0){
              ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_ERROR);
              return -1;
          }
          if (++s->mb_x == s->mb_width) {
              s->mb_x = 0;
              s->mb_y++;
              ff_init_block_index(s);
  
              memmove(r->intra_types_hist, r->intra_types, r->intra_types_stride * 4 * sizeof(*r->intra_types_hist));
              memset(r->intra_types, -1, r->intra_types_stride * 4 * sizeof(*r->intra_types_hist));
  
              if(r->loop_filter && s->mb_y >= 2)
                  r->loop_filter(r, s->mb_y - 2);
  
              if (HAVE_THREADS && (s->avctx->active_thread_type & FF_THREAD_FRAME))
                  ff_thread_report_progress(&s->current_picture_ptr->tf,
                                            s->mb_y - 2, 0);
  
          }
          if(s->mb_x == s->resync_mb_x)
              s->first_slice_line=0;
          s->mb_num_left--;
      }
      ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END);
  
      return s->mb_y == s->mb_height;
  }
  
  /** @} */ // reconstruction group end
  
  /**
   * Initialize decoder.
   */
  av_cold int ff_rv34_decode_init(AVCodecContext *avctx)
  {
      RV34DecContext *r = avctx->priv_data;
      MpegEncContext *s = &r->s;
      int ret;
  
      ff_mpv_decode_defaults(s);
      ff_mpv_decode_init(s, avctx);
      s->out_format = FMT_H263;
  
      avctx->pix_fmt = AV_PIX_FMT_YUV420P;
      avctx->has_b_frames = 1;
      s->low_delay = 0;
  
      ff_mpv_idct_init(s);
      if ((ret = ff_mpv_common_init(s)) < 0)
          return ret;
  
      ff_h264_pred_init(&r->h, AV_CODEC_ID_RV40, 8, 1);
  
  #if CONFIG_RV30_DECODER
      if (avctx->codec_id == AV_CODEC_ID_RV30)
          ff_rv30dsp_init(&r->rdsp);
  #endif
  #if CONFIG_RV40_DECODER
      if (avctx->codec_id == AV_CODEC_ID_RV40)
          ff_rv40dsp_init(&r->rdsp);
  #endif
  
      if ((ret = rv34_decoder_alloc(r)) < 0) {
          ff_mpv_common_end(&r->s);
          return ret;
      }
  
      if(!intra_vlcs[0].cbppattern[0].bits)
          rv34_init_tables();
  
      avctx->internal->allocate_progress = 1;
  
      return 0;
  }
  
  int ff_rv34_decode_init_thread_copy(AVCodecContext *avctx)
  {
      int err;
      RV34DecContext *r = avctx->priv_data;
  
      r->s.avctx = avctx;
  
      if (avctx->internal->is_copy) {
          r->tmp_b_block_base = NULL;
          r->cbp_chroma       = NULL;
          r->cbp_luma         = NULL;
          r->deblock_coefs    = NULL;
          r->intra_types_hist = NULL;
          r->mb_type          = NULL;
  
          ff_mpv_idct_init(&r->s);
  
          if ((err = ff_mpv_common_init(&r->s)) < 0)
              return err;
          if ((err = rv34_decoder_alloc(r)) < 0) {
              ff_mpv_common_end(&r->s);
              return err;
          }
      }
  
      return 0;
  }
  
  int ff_rv34_decode_update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
  {
      RV34DecContext *r = dst->priv_data, *r1 = src->priv_data;
      MpegEncContext * const s = &r->s, * const s1 = &r1->s;
      int err;
  
      if (dst == src || !s1->context_initialized)
          return 0;
  
      if (s->height != s1->height || s->width != s1->width) {
          s->height = s1->height;
          s->width  = s1->width;
          if ((err = ff_mpv_common_frame_size_change(s)) < 0)
              return err;
          if ((err = rv34_decoder_realloc(r)) < 0)
              return err;
      }
  
      r->cur_pts  = r1->cur_pts;
      r->last_pts = r1->last_pts;
      r->next_pts = r1->next_pts;
  
      memset(&r->si, 0, sizeof(r->si));
  
      // Do no call ff_mpeg_update_thread_context on a partially initialized
      // decoder context.
      if (!s1->context_initialized)
          return 0;
  
      return ff_mpeg_update_thread_context(dst, src);
  }
  
  static int get_slice_offset(AVCodecContext *avctx, const uint8_t *buf, int n, int slice_count, int buf_size)
  {
      if (n < slice_count) {
          if(avctx->slice_count) return avctx->slice_offset[n];
          else                   return AV_RL32(buf + n*8 - 4) == 1 ? AV_RL32(buf + n*8) :  AV_RB32(buf + n*8);
      } else
          return buf_size;
  }
  
  static int finish_frame(AVCodecContext *avctx, AVFrame *pict)
  {
      RV34DecContext *r = avctx->priv_data;
      MpegEncContext *s = &r->s;
      int got_picture = 0, ret;
  
      ff_er_frame_end(&s->er);
      ff_mpv_frame_end(s);
      s->mb_num_left = 0;
  
      if (HAVE_THREADS && (s->avctx->active_thread_type & FF_THREAD_FRAME))
          ff_thread_report_progress(&s->current_picture_ptr->tf, INT_MAX, 0);
  
      if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {
          if ((ret = av_frame_ref(pict, s->current_picture_ptr->f)) < 0)
              return ret;
          ff_print_debug_info(s, s->current_picture_ptr, pict);
          ff_mpv_export_qp_table(s, pict, s->current_picture_ptr, FF_QSCALE_TYPE_MPEG1);
          got_picture = 1;
      } else if (s->last_picture_ptr) {
          if ((ret = av_frame_ref(pict, s->last_picture_ptr->f)) < 0)
              return ret;
          ff_print_debug_info(s, s->last_picture_ptr, pict);
          ff_mpv_export_qp_table(s, pict, s->last_picture_ptr, FF_QSCALE_TYPE_MPEG1);
          got_picture = 1;
      }
  
      return got_picture;
  }
  
  static AVRational update_sar(int old_w, int old_h, AVRational sar, int new_w, int new_h)
  {
      // attempt to keep aspect during typical resolution switches
      if (!sar.num)
          sar = (AVRational){1, 1};
  
      sar = av_mul_q(sar, av_mul_q((AVRational){new_h, new_w}, (AVRational){old_w, old_h}));
      return sar;
  }
  
  int ff_rv34_decode_frame(AVCodecContext *avctx,
                              void *data, int *got_picture_ptr,
                              AVPacket *avpkt)
  {
      const uint8_t *buf = avpkt->data;
      int buf_size = avpkt->size;
      RV34DecContext *r = avctx->priv_data;
      MpegEncContext *s = &r->s;
      AVFrame *pict = data;
      SliceInfo si;
      int i, ret;
      int slice_count;
      const uint8_t *slices_hdr = NULL;
      int last = 0;
      int faulty_b = 0;
      int offset;
  
      /* no supplementary picture */
      if (buf_size == 0) {
          /* special case for last picture */
          if (s->low_delay==0 && s->next_picture_ptr) {
              if ((ret = av_frame_ref(pict, s->next_picture_ptr->f)) < 0)
                  return ret;
              s->next_picture_ptr = NULL;
  
              *got_picture_ptr = 1;
          }
          return 0;
      }
  
      if(!avctx->slice_count){
          slice_count = (*buf++) + 1;
          slices_hdr = buf + 4;
          buf += 8 * slice_count;
          buf_size -= 1 + 8 * slice_count;
      }else
          slice_count = avctx->slice_count;
  
      offset = get_slice_offset(avctx, slices_hdr, 0, slice_count, buf_size);
      //parse first slice header to check whether this frame can be decoded
      if(offset < 0 || offset > buf_size){
          av_log(avctx, AV_LOG_ERROR, "Slice offset is invalid\n");
          return AVERROR_INVALIDDATA;
      }
      init_get_bits(&s->gb, buf+offset, (buf_size-offset)*8);
      if(r->parse_slice_header(r, &r->s.gb, &si) < 0 || si.start){
          av_log(avctx, AV_LOG_ERROR, "First slice header is incorrect\n");
          return AVERROR_INVALIDDATA;
      }
      if ((!s->last_picture_ptr || !s->last_picture_ptr->f->data[0]) &&
          si.type == AV_PICTURE_TYPE_B) {
          av_log(avctx, AV_LOG_ERROR, "Invalid decoder state: B-frame without "
                 "reference data.\n");
          faulty_b = 1;
      }
      if(   (avctx->skip_frame >= AVDISCARD_NONREF && si.type==AV_PICTURE_TYPE_B)
         || (avctx->skip_frame >= AVDISCARD_NONKEY && si.type!=AV_PICTURE_TYPE_I)
         ||  avctx->skip_frame >= AVDISCARD_ALL)
          return avpkt->size;
  
      /* first slice */
      if (si.start == 0) {
          if (s->mb_num_left > 0 && s->current_picture_ptr) {
              av_log(avctx, AV_LOG_ERROR, "New frame but still %d MB left.\n",
                     s->mb_num_left);
              ff_er_frame_end(&s->er);
              ff_mpv_frame_end(s);
          }
  
          if (s->width != si.width || s->height != si.height) {
              int err;
  
              av_log(s->avctx, AV_LOG_WARNING, "Changing dimensions to %dx%d\n",
                     si.width, si.height);
  
              if (av_image_check_size(si.width, si.height, 0, s->avctx))
                  return AVERROR_INVALIDDATA;
  
              s->avctx->sample_aspect_ratio = update_sar(
                  s->width, s->height, s->avctx->sample_aspect_ratio,
                  si.width, si.height);
              s->width  = si.width;
              s->height = si.height;
  
              err = ff_set_dimensions(s->avctx, s->width, s->height);
              if (err < 0)
                  return err;
  
              if ((err = ff_mpv_common_frame_size_change(s)) < 0)
                  return err;
              if ((err = rv34_decoder_realloc(r)) < 0)
                  return err;
          }
          if (faulty_b)
              return AVERROR_INVALIDDATA;
          s->pict_type = si.type ? si.type : AV_PICTURE_TYPE_I;
          if (ff_mpv_frame_start(s, s->avctx) < 0)
              return -1;
          ff_mpeg_er_frame_start(s);
          if (!r->tmp_b_block_base) {
              int i;
  
              r->tmp_b_block_base = av_malloc(s->linesize * 48);
              for (i = 0; i < 2; i++)
                  r->tmp_b_block_y[i] = r->tmp_b_block_base
                                        + i * 16 * s->linesize;
              for (i = 0; i < 4; i++)
                  r->tmp_b_block_uv[i] = r->tmp_b_block_base + 32 * s->linesize
                                         + (i >> 1) * 8 * s->uvlinesize
                                         + (i &  1) * 16;
          }
          r->cur_pts = si.pts;
          if (s->pict_type != AV_PICTURE_TYPE_B) {
              r->last_pts = r->next_pts;
              r->next_pts = r->cur_pts;
          } else {
              int refdist = GET_PTS_DIFF(r->next_pts, r->last_pts);
              int dist0   = GET_PTS_DIFF(r->cur_pts,  r->last_pts);
              int dist1   = GET_PTS_DIFF(r->next_pts, r->cur_pts);
  
              if(!refdist){
                  r->mv_weight1 = r->mv_weight2 = r->weight1 = r->weight2 = 8192;
                  r->scaled_weight = 0;
              }else{
                  if (FFMAX(dist0, dist1) > refdist)
                      av_log(avctx, AV_LOG_TRACE, "distance overflow\n");
  
                  r->mv_weight1 = (dist0 << 14) / refdist;
                  r->mv_weight2 = (dist1 << 14) / refdist;
                  if((r->mv_weight1|r->mv_weight2) & 511){
                      r->weight1 = r->mv_weight1;
                      r->weight2 = r->mv_weight2;
                      r->scaled_weight = 0;
                  }else{
                      r->weight1 = r->mv_weight1 >> 9;
                      r->weight2 = r->mv_weight2 >> 9;
                      r->scaled_weight = 1;
                  }
              }
          }
          s->mb_x = s->mb_y = 0;
          ff_thread_finish_setup(s->avctx);
      } else if (HAVE_THREADS &&
                 (s->avctx->active_thread_type & FF_THREAD_FRAME)) {
          av_log(s->avctx, AV_LOG_ERROR, "Decoder needs full frames in frame "
                 "multithreading mode (start MB is %d).\n", si.start);
          return AVERROR_INVALIDDATA;
      }
  
      for(i = 0; i < slice_count; i++){
          int offset  = get_slice_offset(avctx, slices_hdr, i  , slice_count, buf_size);
          int offset1 = get_slice_offset(avctx, slices_hdr, i+1, slice_count, buf_size);
          int size;
  
          if(offset < 0 || offset > offset1 || offset1 > buf_size){
              av_log(avctx, AV_LOG_ERROR, "Slice offset is invalid\n");
              break;
          }
          size = offset1 - offset;
  
          r->si.end = s->mb_width * s->mb_height;
          s->mb_num_left = r->s.mb_x + r->s.mb_y*r->s.mb_width - r->si.start;
  
          if(i+1 < slice_count){
              int offset2 = get_slice_offset(avctx, slices_hdr, i+2, slice_count, buf_size);
              if (offset2 < offset1 || offset2 > buf_size) {
                  av_log(avctx, AV_LOG_ERROR, "Slice offset is invalid\n");
                  break;
              }
              init_get_bits(&s->gb, buf+offset1, (buf_size-offset1)*8);
              if(r->parse_slice_header(r, &r->s.gb, &si) < 0){
                  size = offset2 - offset;
              }else
                  r->si.end = si.start;
          }
          av_assert0 (size >= 0 && size <= buf_size - offset);
          last = rv34_decode_slice(r, r->si.end, buf + offset, size);
          if(last)
              break;
      }
  
      if (s->current_picture_ptr) {
          if (last) {
              if(r->loop_filter)
                  r->loop_filter(r, s->mb_height - 1);
  
              ret = finish_frame(avctx, pict);
              if (ret < 0)
                  return ret;
              *got_picture_ptr = ret;
          } else if (HAVE_THREADS &&
                     (s->avctx->active_thread_type & FF_THREAD_FRAME)) {
              av_log(avctx, AV_LOG_INFO, "marking unfished frame as finished\n");
              /* always mark the current frame as finished, frame-mt supports
               * only complete frames */
              ff_er_frame_end(&s->er);
              ff_mpv_frame_end(s);
              s->mb_num_left = 0;
              ff_thread_report_progress(&s->current_picture_ptr->tf, INT_MAX, 0);
              return AVERROR_INVALIDDATA;
          }
      }
  
      return avpkt->size;
  }
  
  av_cold int ff_rv34_decode_end(AVCodecContext *avctx)
  {
      RV34DecContext *r = avctx->priv_data;
  
      ff_mpv_common_end(&r->s);
      rv34_decoder_free(r);
  
      return 0;
  }
  