text: /*
   * MPEG4 encoder.
   * Copyright (c) 2000,2001 Fabrice Bellard
   * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
   *
   * This file is part of Libav.
   *
   * Libav 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.
   *
   * Libav 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 Libav; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "libavutil/log.h"
  #include "libavutil/opt.h"
  #include "mpegvideo.h"
  #include "h263.h"
  #include "mpeg4video.h"
  
  //The uni_DCtab_* tables below contain unified bits+length tables to encode DC
  //differences in mpeg4. Unified in the sense that the specification specifies
  //this encoding in several steps.
  static uint8_t uni_DCtab_lum_len[512];
  static uint8_t uni_DCtab_chrom_len[512];
  static uint16_t uni_DCtab_lum_bits[512];
  static uint16_t uni_DCtab_chrom_bits[512];
  
  //unified encoding tables for run length encoding of coefficients
  //unified in the sense that the specification specifies the encoding in several steps.
  static uint32_t uni_mpeg4_intra_rl_bits[64*64*2*2];
  static uint8_t  uni_mpeg4_intra_rl_len [64*64*2*2];
  static uint32_t uni_mpeg4_inter_rl_bits[64*64*2*2];
  static uint8_t  uni_mpeg4_inter_rl_len [64*64*2*2];
  //#define UNI_MPEG4_ENC_INDEX(last,run,level) ((last)*128 + (run)*256 + (level))
  //#define UNI_MPEG4_ENC_INDEX(last,run,level) ((last)*128*64 + (run) + (level)*64)
  #define UNI_MPEG4_ENC_INDEX(last,run,level) ((last)*128*64 + (run)*128 + (level))
  
  /* mpeg4
  inter
  max level: 24/6
  max run: 53/63
  
  intra
  max level: 53/16
  max run: 29/41
  */
  
  
  /**
   * Return the number of bits that encoding the 8x8 block in block would need.
   * @param[in]  block_last_index last index in scantable order that refers to a non zero element in block.
   */
  static inline int get_block_rate(MpegEncContext * s, DCTELEM block[64], int block_last_index, uint8_t scantable[64]){
      int last=0;
      int j;
      int rate=0;
  
      for(j=1; j<=block_last_index; j++){
          const int index= scantable[j];
          int level= block[index];
          if(level){
              level+= 64;
              if((level&(~127)) == 0){
                  if(j<block_last_index) rate+= s->intra_ac_vlc_length     [UNI_AC_ENC_INDEX(j-last-1, level)];
                  else                   rate+= s->intra_ac_vlc_last_length[UNI_AC_ENC_INDEX(j-last-1, level)];
              }else
                  rate += s->ac_esc_length;
  
              last= j;
          }
      }
  
      return rate;
  }
  
  
  /**
   * Restore the ac coefficients in block that have been changed by decide_ac_pred().
   * This function also restores s->block_last_index.
   * @param[in,out] block MB coefficients, these will be restored
   * @param[in] dir ac prediction direction for each 8x8 block
   * @param[out] st scantable for each 8x8 block
   * @param[in] zigzag_last_index index refering to the last non zero coefficient in zigzag order
   */
  static inline void restore_ac_coeffs(MpegEncContext * s, DCTELEM block[6][64], const int dir[6], uint8_t *st[6], const int zigzag_last_index[6])
  {
      int i, n;
      memcpy(s->block_last_index, zigzag_last_index, sizeof(int)*6);
  
      for(n=0; n<6; n++){
          int16_t *ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
  
          st[n]= s->intra_scantable.permutated;
          if(dir[n]){
              /* top prediction */
              for(i=1; i<8; i++){
                  block[n][s->dsp.idct_permutation[i   ]] = ac_val[i+8];
              }
          }else{
              /* left prediction */
              for(i=1; i<8; i++){
                  block[n][s->dsp.idct_permutation[i<<3]]= ac_val[i  ];
              }
          }
      }
  }
  
  /**
   * Return the optimal value (0 or 1) for the ac_pred element for the given MB in mpeg4.
   * This function will also update s->block_last_index and s->ac_val.
   * @param[in,out] block MB coefficients, these will be updated if 1 is returned
   * @param[in] dir ac prediction direction for each 8x8 block
   * @param[out] st scantable for each 8x8 block
   * @param[out] zigzag_last_index index refering to the last non zero coefficient in zigzag order
   */
  static inline int decide_ac_pred(MpegEncContext * s, DCTELEM block[6][64], const int dir[6], uint8_t *st[6], int zigzag_last_index[6])
  {
      int score= 0;
      int i, n;
      int8_t * const qscale_table = s->current_picture.f.qscale_table;
  
      memcpy(zigzag_last_index, s->block_last_index, sizeof(int)*6);
  
      for(n=0; n<6; n++){
          int16_t *ac_val, *ac_val1;
  
          score -= get_block_rate(s, block[n], s->block_last_index[n], s->intra_scantable.permutated);
  
          ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
          ac_val1= ac_val;
          if(dir[n]){
              const int xy= s->mb_x + s->mb_y*s->mb_stride - s->mb_stride;
              /* top prediction */
              ac_val-= s->block_wrap[n]*16;
              if(s->mb_y==0 || s->qscale == qscale_table[xy] || n==2 || n==3){
                  /* same qscale */
                  for(i=1; i<8; i++){
                      const int level= block[n][s->dsp.idct_permutation[i   ]];
                      block[n][s->dsp.idct_permutation[i   ]] = level - ac_val[i+8];
                      ac_val1[i  ]=    block[n][s->dsp.idct_permutation[i<<3]];
                      ac_val1[i+8]= level;
                  }
              }else{
                  /* different qscale, we must rescale */
                  for(i=1; i<8; i++){
                      const int level= block[n][s->dsp.idct_permutation[i   ]];
                      block[n][s->dsp.idct_permutation[i   ]] = level - ROUNDED_DIV(ac_val[i + 8]*qscale_table[xy], s->qscale);
                      ac_val1[i  ]=    block[n][s->dsp.idct_permutation[i<<3]];
                      ac_val1[i+8]= level;
                  }
              }
              st[n]= s->intra_h_scantable.permutated;
          }else{
              const int xy= s->mb_x-1 + s->mb_y*s->mb_stride;
              /* left prediction */
              ac_val-= 16;
              if(s->mb_x==0 || s->qscale == qscale_table[xy] || n==1 || n==3){
                  /* same qscale */
                  for(i=1; i<8; i++){
                      const int level= block[n][s->dsp.idct_permutation[i<<3]];
                      block[n][s->dsp.idct_permutation[i<<3]]= level - ac_val[i];
                      ac_val1[i  ]= level;
                      ac_val1[i+8]=    block[n][s->dsp.idct_permutation[i   ]];
                  }
              }else{
                  /* different qscale, we must rescale */
                  for(i=1; i<8; i++){
                      const int level= block[n][s->dsp.idct_permutation[i<<3]];
                      block[n][s->dsp.idct_permutation[i<<3]]= level - ROUNDED_DIV(ac_val[i]*qscale_table[xy], s->qscale);
                      ac_val1[i  ]= level;
                      ac_val1[i+8]=    block[n][s->dsp.idct_permutation[i   ]];
                  }
              }
              st[n]= s->intra_v_scantable.permutated;
          }
  
          for(i=63; i>0; i--) //FIXME optimize
              if(block[n][ st[n][i] ]) break;
          s->block_last_index[n]= i;
  
          score += get_block_rate(s, block[n], s->block_last_index[n], st[n]);
      }
  
      if(score < 0){
          return 1;
      }else{
          restore_ac_coeffs(s, block, dir, st, zigzag_last_index);
          return 0;
      }
  }
  
  /**
   * modify mb_type & qscale so that encoding is acually possible in mpeg4
   */
  void ff_clean_mpeg4_qscales(MpegEncContext *s){
      int i;
      int8_t * const qscale_table = s->current_picture.f.qscale_table;
  
      ff_clean_h263_qscales(s);
  
      if(s->pict_type== AV_PICTURE_TYPE_B){
          int odd=0;
          /* ok, come on, this isn't funny anymore, there's more code for handling this mpeg4 mess than for the actual adaptive quantization */
  
          for(i=0; i<s->mb_num; i++){
              int mb_xy= s->mb_index2xy[i];
              odd += qscale_table[mb_xy]&1;
          }
  
          if(2*odd > s->mb_num) odd=1;
          else                  odd=0;
  
          for(i=0; i<s->mb_num; i++){
              int mb_xy= s->mb_index2xy[i];
              if((qscale_table[mb_xy]&1) != odd)
                  qscale_table[mb_xy]++;
              if(qscale_table[mb_xy] > 31)
                  qscale_table[mb_xy]= 31;
          }
  
          for(i=1; i<s->mb_num; i++){
              int mb_xy= s->mb_index2xy[i];
              if(qscale_table[mb_xy] != qscale_table[s->mb_index2xy[i-1]] && (s->mb_type[mb_xy]&CANDIDATE_MB_TYPE_DIRECT)){
                  s->mb_type[mb_xy]|= CANDIDATE_MB_TYPE_BIDIR;
              }
          }
      }
  }
  
  
  /**
   * Encode the dc value.
   * @param n block index (0-3 are luma, 4-5 are chroma)
   */
  static inline void mpeg4_encode_dc(PutBitContext * s, int level, int n)
  {
  #if 1
      /* DC will overflow if level is outside the [-255,255] range. */
      level+=256;
      if (n < 4) {
          /* luminance */
          put_bits(s, uni_DCtab_lum_len[level], uni_DCtab_lum_bits[level]);
      } else {
          /* chrominance */
          put_bits(s, uni_DCtab_chrom_len[level], uni_DCtab_chrom_bits[level]);
      }
  #else
      int size, v;
      /* find number of bits */
      size = 0;
      v = abs(level);
      while (v) {
          v >>= 1;
          size++;
      }
  
      if (n < 4) {
          /* luminance */
          put_bits(&s->pb, ff_mpeg4_DCtab_lum[size][1], ff_mpeg4_DCtab_lum[size][0]);
      } else {
          /* chrominance */
          put_bits(&s->pb, ff_mpeg4_DCtab_chrom[size][1], ff_mpeg4_DCtab_chrom[size][0]);
      }
  
      /* encode remaining bits */
      if (size > 0) {
          if (level < 0)
              level = (-level) ^ ((1 << size) - 1);
          put_bits(&s->pb, size, level);
          if (size > 8)
              put_bits(&s->pb, 1, 1);
      }
  #endif
  }
  
  static inline int mpeg4_get_dc_length(int level, int n){
      if (n < 4) {
          return uni_DCtab_lum_len[level + 256];
      } else {
          return uni_DCtab_chrom_len[level + 256];
      }
  }
  
  /**
   * Encode an 8x8 block.
   * @param n block index (0-3 are luma, 4-5 are chroma)
   */
  static inline void mpeg4_encode_block(MpegEncContext * s, DCTELEM * block, int n, int intra_dc,
                                 uint8_t *scan_table, PutBitContext *dc_pb, PutBitContext *ac_pb)
  {
      int i, last_non_zero;
      uint32_t *bits_tab;
      uint8_t *len_tab;
      const int last_index = s->block_last_index[n];
  
      if (s->mb_intra) { //Note gcc (3.2.1 at least) will optimize this away
          /* mpeg4 based DC predictor */
          mpeg4_encode_dc(dc_pb, intra_dc, n);
          if(last_index<1) return;
          i = 1;
          bits_tab= uni_mpeg4_intra_rl_bits;
          len_tab = uni_mpeg4_intra_rl_len;
      } else {
          if(last_index<0) return;
          i = 0;
          bits_tab= uni_mpeg4_inter_rl_bits;
          len_tab = uni_mpeg4_inter_rl_len;
      }
  
      /* AC coefs */
      last_non_zero = i - 1;
      for (; i < last_index; i++) {
          int level = block[ scan_table[i] ];
          if (level) {
              int run = i - last_non_zero - 1;
              level+=64;
              if((level&(~127)) == 0){
                  const int index= UNI_MPEG4_ENC_INDEX(0, run, level);
                  put_bits(ac_pb, len_tab[index], bits_tab[index]);
              }else{ //ESC3
                  put_bits(ac_pb, 7+2+1+6+1+12+1, (3<<23)+(3<<21)+(0<<20)+(run<<14)+(1<<13)+(((level-64)&0xfff)<<1)+1);
              }
              last_non_zero = i;
          }
      }
      /*if(i<=last_index)*/{
          int level = block[ scan_table[i] ];
          int run = i - last_non_zero - 1;
          level+=64;
          if((level&(~127)) == 0){
              const int index= UNI_MPEG4_ENC_INDEX(1, run, level);
              put_bits(ac_pb, len_tab[index], bits_tab[index]);
          }else{ //ESC3
              put_bits(ac_pb, 7+2+1+6+1+12+1, (3<<23)+(3<<21)+(1<<20)+(run<<14)+(1<<13)+(((level-64)&0xfff)<<1)+1);
          }
      }
  }
  
  static int mpeg4_get_block_length(MpegEncContext * s, DCTELEM * block, int n, int intra_dc,
                                 uint8_t *scan_table)
  {
      int i, last_non_zero;
      uint8_t *len_tab;
      const int last_index = s->block_last_index[n];
      int len=0;
  
      if (s->mb_intra) { //Note gcc (3.2.1 at least) will optimize this away
          /* mpeg4 based DC predictor */
          len += mpeg4_get_dc_length(intra_dc, n);
          if(last_index<1) return len;
          i = 1;
          len_tab = uni_mpeg4_intra_rl_len;
      } else {
          if(last_index<0) return 0;
          i = 0;
          len_tab = uni_mpeg4_inter_rl_len;
      }
  
      /* AC coefs */
      last_non_zero = i - 1;
      for (; i < last_index; i++) {
          int level = block[ scan_table[i] ];
          if (level) {
              int run = i - last_non_zero - 1;
              level+=64;
              if((level&(~127)) == 0){
                  const int index= UNI_MPEG4_ENC_INDEX(0, run, level);
                  len += len_tab[index];
              }else{ //ESC3
                  len += 7+2+1+6+1+12+1;
              }
              last_non_zero = i;
          }
      }
      /*if(i<=last_index)*/{
          int level = block[ scan_table[i] ];
          int run = i - last_non_zero - 1;
          level+=64;
          if((level&(~127)) == 0){
              const int index= UNI_MPEG4_ENC_INDEX(1, run, level);
              len += len_tab[index];
          }else{ //ESC3
              len += 7+2+1+6+1+12+1;
          }
      }
  
      return len;
  }
  
  static inline void mpeg4_encode_blocks(MpegEncContext * s, DCTELEM block[6][64], int intra_dc[6],
                                 uint8_t **scan_table, PutBitContext *dc_pb, PutBitContext *ac_pb){
      int i;
  
      if(scan_table){
          if(s->flags2 & CODEC_FLAG2_NO_OUTPUT){
              for (i = 0; i < 6; i++) {
                  skip_put_bits(&s->pb, mpeg4_get_block_length(s, block[i], i, intra_dc[i], scan_table[i]));
              }
          }else{
              /* encode each block */
              for (i = 0; i < 6; i++) {
                  mpeg4_encode_block(s, block[i], i, intra_dc[i], scan_table[i], dc_pb, ac_pb);
              }
          }
      }else{
          if(s->flags2 & CODEC_FLAG2_NO_OUTPUT){
              for (i = 0; i < 6; i++) {
                  skip_put_bits(&s->pb, mpeg4_get_block_length(s, block[i], i, 0, s->intra_scantable.permutated));
              }
          }else{
              /* encode each block */
              for (i = 0; i < 6; i++) {
                  mpeg4_encode_block(s, block[i], i, 0, s->intra_scantable.permutated, dc_pb, ac_pb);
              }
          }
      }
  }
  
  static inline int get_b_cbp(MpegEncContext * s, DCTELEM block[6][64],
                              int motion_x, int motion_y, int mb_type)
  {
      int cbp = 0, i;
  
      if (s->flags & CODEC_FLAG_CBP_RD) {
          int score = 0;
          const int lambda = s->lambda2 >> (FF_LAMBDA_SHIFT - 6);
  
          for (i = 0; i < 6; i++)
              if (s->coded_score[i] < 0) {
                  score += s->coded_score[i];
                  cbp   |= 1 << (5 - i);
              }
  
          if (cbp) {
              int zero_score = -6;
              if ((motion_x | motion_y | s->dquant | mb_type) == 0)
                  zero_score -= 4; //2*MV + mb_type + cbp bit
  
              zero_score *= lambda;
              if (zero_score <= score)
                  cbp = 0;
          }
  
          for (i = 0; i < 6; i++) {
              if (s->block_last_index[i] >= 0 && ((cbp >> (5 - i)) & 1) == 0) {
                  s->block_last_index[i] = -1;
                  s->dsp.clear_block(s->block[i]);
              }
          }
      } else {
          for (i = 0; i < 6; i++) {
              if (s->block_last_index[i] >= 0)
                  cbp |= 1 << (5 - i);
          }
      }
      return cbp;
  }
  
  //FIXME this is duplicated to h263.c
  static const int dquant_code[5]= {1,0,9,2,3};
  
  void mpeg4_encode_mb(MpegEncContext * s,
                      DCTELEM block[6][64],
                      int motion_x, int motion_y)
  {
      int cbpc, cbpy, pred_x, pred_y;
      PutBitContext * const pb2    = s->data_partitioning                         ? &s->pb2    : &s->pb;
      PutBitContext * const tex_pb = s->data_partitioning && s->pict_type!=AV_PICTURE_TYPE_B ? &s->tex_pb : &s->pb;
      PutBitContext * const dc_pb  = s->data_partitioning && s->pict_type!=AV_PICTURE_TYPE_I ? &s->pb2    : &s->pb;
      const int interleaved_stats= (s->flags&CODEC_FLAG_PASS1) && !s->data_partitioning ? 1 : 0;
  
      if (!s->mb_intra) {
          int i, cbp;
  
          if(s->pict_type==AV_PICTURE_TYPE_B){
              static const int mb_type_table[8]= {-1, 3, 2, 1,-1,-1,-1, 0}; /* convert from mv_dir to type */
              int mb_type=  mb_type_table[s->mv_dir];
  
              if(s->mb_x==0){
                  for(i=0; i<2; i++){
                      s->last_mv[i][0][0]=
                      s->last_mv[i][0][1]=
                      s->last_mv[i][1][0]=
                      s->last_mv[i][1][1]= 0;
                  }
              }
  
              assert(s->dquant>=-2 && s->dquant<=2);
              assert((s->dquant&1)==0);
              assert(mb_type>=0);
  
              /* nothing to do if this MB was skipped in the next P Frame */
              if (s->next_picture.f.mbskip_table[s->mb_y * s->mb_stride + s->mb_x]) { //FIXME avoid DCT & ...
                  s->skip_count++;
                  s->mv[0][0][0]=
                  s->mv[0][0][1]=
                  s->mv[1][0][0]=
                  s->mv[1][0][1]= 0;
                  s->mv_dir= MV_DIR_FORWARD; //doesn't matter
                  s->qscale -= s->dquant;
  //                s->mb_skipped=1;
  
                  return;
              }
  
              cbp= get_b_cbp(s, block, motion_x, motion_y, mb_type);
  
              if ((cbp | motion_x | motion_y | mb_type) ==0) {
                  /* direct MB with MV={0,0} */
                  assert(s->dquant==0);
  
                  put_bits(&s->pb, 1, 1); /* mb not coded modb1=1 */
  
                  if(interleaved_stats){
                      s->misc_bits++;
                      s->last_bits++;
                  }
                  s->skip_count++;
                  return;
              }
  
              put_bits(&s->pb, 1, 0);     /* mb coded modb1=0 */
              put_bits(&s->pb, 1, cbp ? 0 : 1); /* modb2 */ //FIXME merge
              put_bits(&s->pb, mb_type+1, 1); // this table is so simple that we don't need it :)
              if(cbp) put_bits(&s->pb, 6, cbp);
  
              if(cbp && mb_type){
                  if(s->dquant)
                      put_bits(&s->pb, 2, (s->dquant>>2)+3);
                  else
                      put_bits(&s->pb, 1, 0);
              }else
                  s->qscale -= s->dquant;
  
              if(!s->progressive_sequence){
                  if(cbp)
                      put_bits(&s->pb, 1, s->interlaced_dct);
                  if(mb_type) // not direct mode
                      put_bits(&s->pb, 1, s->mv_type == MV_TYPE_FIELD);
              }
  
              if(interleaved_stats){
                  s->misc_bits+= get_bits_diff(s);
              }
  
              if(mb_type == 0){
                  assert(s->mv_dir & MV_DIRECT);
                  ff_h263_encode_motion_vector(s, motion_x, motion_y, 1);
                  s->b_count++;
                  s->f_count++;
              }else{
                  assert(mb_type > 0 && mb_type < 4);
                  if(s->mv_type != MV_TYPE_FIELD){
                      if(s->mv_dir & MV_DIR_FORWARD){
                          ff_h263_encode_motion_vector(s, s->mv[0][0][0] - s->last_mv[0][0][0],
                                                          s->mv[0][0][1] - s->last_mv[0][0][1], s->f_code);
                          s->last_mv[0][0][0]= s->last_mv[0][1][0]= s->mv[0][0][0];
                          s->last_mv[0][0][1]= s->last_mv[0][1][1]= s->mv[0][0][1];
                          s->f_count++;
                      }
                      if(s->mv_dir & MV_DIR_BACKWARD){
                          ff_h263_encode_motion_vector(s, s->mv[1][0][0] - s->last_mv[1][0][0],
                                                          s->mv[1][0][1] - s->last_mv[1][0][1], s->b_code);
                          s->last_mv[1][0][0]= s->last_mv[1][1][0]= s->mv[1][0][0];
                          s->last_mv[1][0][1]= s->last_mv[1][1][1]= s->mv[1][0][1];
                          s->b_count++;
                      }
                  }else{
                      if(s->mv_dir & MV_DIR_FORWARD){
                          put_bits(&s->pb, 1, s->field_select[0][0]);
                          put_bits(&s->pb, 1, s->field_select[0][1]);
                      }
                      if(s->mv_dir & MV_DIR_BACKWARD){
                          put_bits(&s->pb, 1, s->field_select[1][0]);
                          put_bits(&s->pb, 1, s->field_select[1][1]);
                      }
                      if(s->mv_dir & MV_DIR_FORWARD){
                          for(i=0; i<2; i++){
                              ff_h263_encode_motion_vector(s, s->mv[0][i][0] - s->last_mv[0][i][0]  ,
                                                              s->mv[0][i][1] - s->last_mv[0][i][1]/2, s->f_code);
                              s->last_mv[0][i][0]= s->mv[0][i][0];
                              s->last_mv[0][i][1]= s->mv[0][i][1]*2;
                          }
                          s->f_count++;
                      }
                      if(s->mv_dir & MV_DIR_BACKWARD){
                          for(i=0; i<2; i++){
                              ff_h263_encode_motion_vector(s, s->mv[1][i][0] - s->last_mv[1][i][0]  ,
                                                              s->mv[1][i][1] - s->last_mv[1][i][1]/2, s->b_code);
                              s->last_mv[1][i][0]= s->mv[1][i][0];
                              s->last_mv[1][i][1]= s->mv[1][i][1]*2;
                          }
                          s->b_count++;
                      }
                  }
              }
  
              if(interleaved_stats){
                  s->mv_bits+= get_bits_diff(s);
              }
  
              mpeg4_encode_blocks(s, block, NULL, NULL, NULL, &s->pb);
  
              if(interleaved_stats){
                  s->p_tex_bits+= get_bits_diff(s);
              }
  
          }else{ /* s->pict_type==AV_PICTURE_TYPE_B */
              cbp= get_p_cbp(s, block, motion_x, motion_y);
  
              if ((cbp | motion_x | motion_y | s->dquant) == 0 && s->mv_type==MV_TYPE_16X16) {
                  /* check if the B frames can skip it too, as we must skip it if we skip here
                     why didn't they just compress the skip-mb bits instead of reusing them ?! */
                  if(s->max_b_frames>0){
                      int i;
                      int x,y, offset;
                      uint8_t *p_pic;
  
                      x= s->mb_x*16;
                      y= s->mb_y*16;
                      if(x+16 > s->width)  x= s->width-16;
                      if(y+16 > s->height) y= s->height-16;
  
                      offset= x + y*s->linesize;
                      p_pic = s->new_picture.f.data[0] + offset;
  
                      s->mb_skipped=1;
                      for(i=0; i<s->max_b_frames; i++){
                          uint8_t *b_pic;
                          int diff;
                          Picture *pic= s->reordered_input_picture[i+1];
  
                          if (pic == NULL || pic->f.pict_type != AV_PICTURE_TYPE_B)
                              break;
  
                          b_pic = pic->f.data[0] + offset;
                          if (pic->f.type != FF_BUFFER_TYPE_SHARED)
                              b_pic+= INPLACE_OFFSET;
                          diff= s->dsp.sad[0](NULL, p_pic, b_pic, s->linesize, 16);
                          if(diff>s->qscale*70){ //FIXME check that 70 is optimal
                              s->mb_skipped=0;
                              break;
                          }
                      }
                  }else
                      s->mb_skipped=1;
  
                  if(s->mb_skipped==1){
                      /* skip macroblock */
                      put_bits(&s->pb, 1, 1);
  
                      if(interleaved_stats){
                          s->misc_bits++;
                          s->last_bits++;
                      }
                      s->skip_count++;
  
                      return;
                  }
              }
  
              put_bits(&s->pb, 1, 0);     /* mb coded */
              cbpc = cbp & 3;
              cbpy = cbp >> 2;
              cbpy ^= 0xf;
              if(s->mv_type==MV_TYPE_16X16){
                  if(s->dquant) cbpc+= 8;
                  put_bits(&s->pb,
                          ff_h263_inter_MCBPC_bits[cbpc],
                          ff_h263_inter_MCBPC_code[cbpc]);
  
                  put_bits(pb2, ff_h263_cbpy_tab[cbpy][1], ff_h263_cbpy_tab[cbpy][0]);
                  if(s->dquant)
                      put_bits(pb2, 2, dquant_code[s->dquant+2]);
  
                  if(!s->progressive_sequence){
                      if(cbp)
                          put_bits(pb2, 1, s->interlaced_dct);
                      put_bits(pb2, 1, 0);
                  }
  
                  if(interleaved_stats){
                      s->misc_bits+= get_bits_diff(s);
                  }
  
                  /* motion vectors: 16x16 mode */
                  ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
  
                  ff_h263_encode_motion_vector(s, motion_x - pred_x,
                                                  motion_y - pred_y, s->f_code);
              }else if(s->mv_type==MV_TYPE_FIELD){
                  if(s->dquant) cbpc+= 8;
                  put_bits(&s->pb,
                          ff_h263_inter_MCBPC_bits[cbpc],
                          ff_h263_inter_MCBPC_code[cbpc]);
  
                  put_bits(pb2, ff_h263_cbpy_tab[cbpy][1], ff_h263_cbpy_tab[cbpy][0]);
                  if(s->dquant)
                      put_bits(pb2, 2, dquant_code[s->dquant+2]);
  
                  assert(!s->progressive_sequence);
                  if(cbp)
                      put_bits(pb2, 1, s->interlaced_dct);
                  put_bits(pb2, 1, 1);
  
                  if(interleaved_stats){
                      s->misc_bits+= get_bits_diff(s);
                  }
  
                  /* motion vectors: 16x8 interlaced mode */
                  ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
                  pred_y /=2;
  
                  put_bits(&s->pb, 1, s->field_select[0][0]);
                  put_bits(&s->pb, 1, s->field_select[0][1]);
  
                  ff_h263_encode_motion_vector(s, s->mv[0][0][0] - pred_x,
                                                  s->mv[0][0][1] - pred_y, s->f_code);
                  ff_h263_encode_motion_vector(s, s->mv[0][1][0] - pred_x,
                                                  s->mv[0][1][1] - pred_y, s->f_code);
              }else{
                  assert(s->mv_type==MV_TYPE_8X8);
                  put_bits(&s->pb,
                          ff_h263_inter_MCBPC_bits[cbpc+16],
                          ff_h263_inter_MCBPC_code[cbpc+16]);
                  put_bits(pb2, ff_h263_cbpy_tab[cbpy][1], ff_h263_cbpy_tab[cbpy][0]);
  
                  if(!s->progressive_sequence){
                      if(cbp)
                          put_bits(pb2, 1, s->interlaced_dct);
                  }
  
                  if(interleaved_stats){
                      s->misc_bits+= get_bits_diff(s);
                  }
  
                  for(i=0; i<4; i++){
                      /* motion vectors: 8x8 mode*/
                      ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
  
                      ff_h263_encode_motion_vector(s, s->current_picture.f.motion_val[0][ s->block_index[i] ][0] - pred_x,
                                                      s->current_picture.f.motion_val[0][ s->block_index[i] ][1] - pred_y, s->f_code);
                  }
              }
  
              if(interleaved_stats){
                  s->mv_bits+= get_bits_diff(s);
              }
  
              mpeg4_encode_blocks(s, block, NULL, NULL, NULL, tex_pb);
  
              if(interleaved_stats){
                  s->p_tex_bits+= get_bits_diff(s);
              }
              s->f_count++;
          }
      } else {
          int cbp;
          int dc_diff[6];   //dc values with the dc prediction subtracted
          int dir[6];  //prediction direction
          int zigzag_last_index[6];
          uint8_t *scan_table[6];
          int i;
  
          for(i=0; i<6; i++){
              dc_diff[i]= ff_mpeg4_pred_dc(s, i, block[i][0], &dir[i], 1);
          }
  
          if(s->flags & CODEC_FLAG_AC_PRED){
              s->ac_pred= decide_ac_pred(s, block, dir, scan_table, zigzag_last_index);
          }else{
              for(i=0; i<6; i++)
                  scan_table[i]= s->intra_scantable.permutated;
          }
  
          /* compute cbp */
          cbp = 0;
          for (i = 0; i < 6; i++) {
              if (s->block_last_index[i] >= 1)
                  cbp |= 1 << (5 - i);
          }
  
          cbpc = cbp & 3;
          if (s->pict_type == AV_PICTURE_TYPE_I) {
              if(s->dquant) cbpc+=4;
              put_bits(&s->pb,
                  ff_h263_intra_MCBPC_bits[cbpc],
                  ff_h263_intra_MCBPC_code[cbpc]);
          } else {
              if(s->dquant) cbpc+=8;
              put_bits(&s->pb, 1, 0);     /* mb coded */
              put_bits(&s->pb,
                  ff_h263_inter_MCBPC_bits[cbpc + 4],
                  ff_h263_inter_MCBPC_code[cbpc + 4]);
          }
          put_bits(pb2, 1, s->ac_pred);
          cbpy = cbp >> 2;
          put_bits(pb2, ff_h263_cbpy_tab[cbpy][1], ff_h263_cbpy_tab[cbpy][0]);
          if(s->dquant)
              put_bits(dc_pb, 2, dquant_code[s->dquant+2]);
  
          if(!s->progressive_sequence){
              put_bits(dc_pb, 1, s->interlaced_dct);
          }
  
          if(interleaved_stats){
              s->misc_bits+= get_bits_diff(s);
          }
  
          mpeg4_encode_blocks(s, block, dc_diff, scan_table, dc_pb, tex_pb);
  
          if(interleaved_stats){
              s->i_tex_bits+= get_bits_diff(s);
          }
          s->i_count++;
  
          /* restore ac coeffs & last_index stuff if we messed them up with the prediction */
          if(s->ac_pred)
              restore_ac_coeffs(s, block, dir, scan_table, zigzag_last_index);
      }
  }
  
  /**
   * add mpeg4 stuffing bits (01...1)
   */
  void ff_mpeg4_stuffing(PutBitContext * pbc)
  {
      int length;
      put_bits(pbc, 1, 0);
      length= (-put_bits_count(pbc))&7;
      if(length) put_bits(pbc, length, (1<<length)-1);
  }
  
  /* must be called before writing the header */
  void ff_set_mpeg4_time(MpegEncContext * s){
      if(s->pict_type==AV_PICTURE_TYPE_B){
          ff_mpeg4_init_direct_mv(s);
      }else{
          s->last_time_base= s->time_base;
          s->time_base= s->time/s->avctx->time_base.den;
      }
  }
  
  static void mpeg4_encode_gop_header(MpegEncContext * s){
      int hours, minutes, seconds;
      int64_t time;
  
      put_bits(&s->pb, 16, 0);
      put_bits(&s->pb, 16, GOP_STARTCODE);
  
      time = s->current_picture_ptr->f.pts;
      if(s->reordered_input_picture[1])
          time = FFMIN(time, s->reordered_input_picture[1]->f.pts);
      time= time*s->avctx->time_base.num;
  
      seconds= time/s->avctx->time_base.den;
      minutes= seconds/60; seconds %= 60;
      hours= minutes/60; minutes %= 60;
      hours%=24;
  
      put_bits(&s->pb, 5, hours);
      put_bits(&s->pb, 6, minutes);
      put_bits(&s->pb, 1, 1);
      put_bits(&s->pb, 6, seconds);
  
      put_bits(&s->pb, 1, !!(s->flags&CODEC_FLAG_CLOSED_GOP));
      put_bits(&s->pb, 1, 0); //broken link == NO
  
      s->last_time_base= time / s->avctx->time_base.den;
  
      ff_mpeg4_stuffing(&s->pb);
  }
  
  static void mpeg4_encode_visual_object_header(MpegEncContext * s){
      int profile_and_level_indication;
      int vo_ver_id;
  
      if(s->avctx->profile != FF_PROFILE_UNKNOWN){
          profile_and_level_indication = s->avctx->profile << 4;
      }else if(s->max_b_frames || s->quarter_sample){
          profile_and_level_indication= 0xF0; // adv simple
      }else{
          profile_and_level_indication= 0x00; // simple
      }
  
      if(s->avctx->level != FF_LEVEL_UNKNOWN){
          profile_and_level_indication |= s->avctx->level;
      }else{
          profile_and_level_indication |= 1; //level 1
      }
  
      if(profile_and_level_indication>>4 == 0xF){
          vo_ver_id= 5;
      }else{
          vo_ver_id= 1;
      }
  
      //FIXME levels
  
      put_bits(&s->pb, 16, 0);
      put_bits(&s->pb, 16, VOS_STARTCODE);
  
      put_bits(&s->pb, 8, profile_and_level_indication);
  
      put_bits(&s->pb, 16, 0);
      put_bits(&s->pb, 16, VISUAL_OBJ_STARTCODE);
  
      put_bits(&s->pb, 1, 1);
          put_bits(&s->pb, 4, vo_ver_id);
          put_bits(&s->pb, 3, 1); //priority
  
      put_bits(&s->pb, 4, 1); //visual obj type== video obj
  
      put_bits(&s->pb, 1, 0); //video signal type == no clue //FIXME
  
      ff_mpeg4_stuffing(&s->pb);
  }
  
  static void mpeg4_encode_vol_header(MpegEncContext * s, int vo_number, int vol_number)
  {
      int vo_ver_id;
  
      if (!CONFIG_MPEG4_ENCODER)  return;
  
      if(s->max_b_frames || s->quarter_sample){
          vo_ver_id= 5;
          s->vo_type= ADV_SIMPLE_VO_TYPE;
      }else{
          vo_ver_id= 1;
          s->vo_type= SIMPLE_VO_TYPE;
      }
  
      put_bits(&s->pb, 16, 0);
      put_bits(&s->pb, 16, 0x100 + vo_number);        /* video obj */
      put_bits(&s->pb, 16, 0);
      put_bits(&s->pb, 16, 0x120 + vol_number);       /* video obj layer */
  
      put_bits(&s->pb, 1, 0);             /* random access vol */
      put_bits(&s->pb, 8, s->vo_type);    /* video obj type indication */
      if(s->workaround_bugs & FF_BUG_MS) {
          put_bits(&s->pb, 1, 0);         /* is obj layer id= no */
      } else {
          put_bits(&s->pb, 1, 1);         /* is obj layer id= yes */
          put_bits(&s->pb, 4, vo_ver_id); /* is obj layer ver id */
          put_bits(&s->pb, 3, 1);         /* is obj layer priority */
      }
  
      s->aspect_ratio_info= ff_h263_aspect_to_info(s->avctx->sample_aspect_ratio);
  
      put_bits(&s->pb, 4, s->aspect_ratio_info);/* aspect ratio info */
      if (s->aspect_ratio_info == FF_ASPECT_EXTENDED){
          put_bits(&s->pb, 8, s->avctx->sample_aspect_ratio.num);
          put_bits(&s->pb, 8, s->avctx->sample_aspect_ratio.den);
      }
  
      if(s->workaround_bugs & FF_BUG_MS) { //
          put_bits(&s->pb, 1, 0);         /* vol control parameters= no @@@ */
      } else {
          put_bits(&s->pb, 1, 1);         /* vol control parameters= yes */
          put_bits(&s->pb, 2, 1);         /* chroma format YUV 420/YV12 */
          put_bits(&s->pb, 1, s->low_delay);
          put_bits(&s->pb, 1, 0);         /* vbv parameters= no */
      }
  
      put_bits(&s->pb, 2, RECT_SHAPE);    /* vol shape= rectangle */
      put_bits(&s->pb, 1, 1);             /* marker bit */
  
      put_bits(&s->pb, 16, s->avctx->time_base.den);
      if (s->time_increment_bits < 1)
          s->time_increment_bits = 1;
      put_bits(&s->pb, 1, 1);             /* marker bit */
      put_bits(&s->pb, 1, 0);             /* fixed vop rate=no */
      put_bits(&s->pb, 1, 1);             /* marker bit */
      put_bits(&s->pb, 13, s->width);     /* vol width */
      put_bits(&s->pb, 1, 1);             /* marker bit */
      put_bits(&s->pb, 13, s->height);    /* vol height */
      put_bits(&s->pb, 1, 1);             /* marker bit */
      put_bits(&s->pb, 1, s->progressive_sequence ? 0 : 1);
      put_bits(&s->pb, 1, 1);             /* obmc disable */
      if (vo_ver_id == 1) {
          put_bits(&s->pb, 1, s->vol_sprite_usage);       /* sprite enable */
      }else{
          put_bits(&s->pb, 2, s->vol_sprite_usage);       /* sprite enable */
      }
  
      put_bits(&s->pb, 1, 0);             /* not 8 bit == false */
      put_bits(&s->pb, 1, s->mpeg_quant); /* quant type= (0=h263 style)*/
  
      if(s->mpeg_quant){
          ff_write_quant_matrix(&s->pb, s->avctx->intra_matrix);
          ff_write_quant_matrix(&s->pb, s->avctx->inter_matrix);
      }
  
      if (vo_ver_id != 1)
          put_bits(&s->pb, 1, s->quarter_sample);
      put_bits(&s->pb, 1, 1);             /* complexity estimation disable */
      s->resync_marker= s->rtp_mode;
      put_bits(&s->pb, 1, s->resync_marker ? 0 : 1);/* resync marker disable */
      put_bits(&s->pb, 1, s->data_partitioning ? 1 : 0);
      if(s->data_partitioning){
          put_bits(&s->pb, 1, 0);         /* no rvlc */
      }
  
      if (vo_ver_id != 1){
          put_bits(&s->pb, 1, 0);         /* newpred */
          put_bits(&s->pb, 1, 0);         /* reduced res vop */
      }
      put_bits(&s->pb, 1, 0);             /* scalability */
  
      ff_mpeg4_stuffing(&s->pb);
  
      /* user data */
      if(!(s->flags & CODEC_FLAG_BITEXACT)){
          put_bits(&s->pb, 16, 0);
          put_bits(&s->pb, 16, 0x1B2);    /* user_data */
          ff_put_string(&s->pb, LIBAVCODEC_IDENT, 0);
      }
  }
  
  /* write mpeg4 VOP header */
  void mpeg4_encode_picture_header(MpegEncContext * s, int picture_number)
  {
      int time_incr;
      int time_div, time_mod;
  
      if(s->pict_type==AV_PICTURE_TYPE_I){
          if(!(s->flags&CODEC_FLAG_GLOBAL_HEADER)){
              if(s->strict_std_compliance < FF_COMPLIANCE_VERY_STRICT) //HACK, the reference sw is buggy
                  mpeg4_encode_visual_object_header(s);
              if(s->strict_std_compliance < FF_COMPLIANCE_VERY_STRICT || picture_number==0) //HACK, the reference sw is buggy
                  mpeg4_encode_vol_header(s, 0, 0);
          }
          if(!(s->workaround_bugs & FF_BUG_MS))
              mpeg4_encode_gop_header(s);
      }
  
      s->partitioned_frame= s->data_partitioning && s->pict_type!=AV_PICTURE_TYPE_B;
  
      put_bits(&s->pb, 16, 0);                /* vop header */
      put_bits(&s->pb, 16, VOP_STARTCODE);    /* vop header */
      put_bits(&s->pb, 2, s->pict_type - 1);  /* pict type: I = 0 , P = 1 */
  
      assert(s->time>=0);
      time_div= s->time/s->avctx->time_base.den;
      time_mod= s->time%s->avctx->time_base.den;
      time_incr= time_div - s->last_time_base;
      assert(time_incr >= 0);
      while(time_incr--)
          put_bits(&s->pb, 1, 1);
  
      put_bits(&s->pb, 1, 0);
  
      put_bits(&s->pb, 1, 1);                             /* marker */
      put_bits(&s->pb, s->time_increment_bits, time_mod); /* time increment */
      put_bits(&s->pb, 1, 1);                             /* marker */
      put_bits(&s->pb, 1, 1);                             /* vop coded */
      if (    s->pict_type == AV_PICTURE_TYPE_P
          || (s->pict_type == AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE)) {
          put_bits(&s->pb, 1, s->no_rounding);    /* rounding type */
      }
      put_bits(&s->pb, 3, 0);     /* intra dc VLC threshold */
      if(!s->progressive_sequence){
           put_bits(&s->pb, 1, s->current_picture_ptr->f.top_field_first);
           put_bits(&s->pb, 1, s->alternate_scan);
      }
      //FIXME sprite stuff
  
      put_bits(&s->pb, 5, s->qscale);
  
      if (s->pict_type != AV_PICTURE_TYPE_I)
          put_bits(&s->pb, 3, s->f_code); /* fcode_for */
      if (s->pict_type == AV_PICTURE_TYPE_B)
          put_bits(&s->pb, 3, s->b_code); /* fcode_back */
  }
  
  
  static void init_uni_dc_tab(void)
  {
      int level, uni_code, uni_len;
  
      for(level=-256; level<256; level++){
          int size, v, l;
          /* find number of bits */
          size = 0;
          v = abs(level);
          while (v) {
              v >>= 1;
              size++;
          }
  
          if (level < 0)
              l= (-level) ^ ((1 << size) - 1);
          else
              l= level;
  
          /* luminance */
          uni_code= ff_mpeg4_DCtab_lum[size][0];
          uni_len = ff_mpeg4_DCtab_lum[size][1];
  
          if (size > 0) {
              uni_code<<=size; uni_code|=l;
              uni_len+=size;
              if (size > 8){
                  uni_code<<=1; uni_code|=1;
                  uni_len++;
              }
          }
          uni_DCtab_lum_bits[level+256]= uni_code;
          uni_DCtab_lum_len [level+256]= uni_len;
  
          /* chrominance */
          uni_code= ff_mpeg4_DCtab_chrom[size][0];
          uni_len = ff_mpeg4_DCtab_chrom[size][1];
  
          if (size > 0) {
              uni_code<<=size; uni_code|=l;
              uni_len+=size;
              if (size > 8){
                  uni_code<<=1; uni_code|=1;
                  uni_len++;
              }
          }
          uni_DCtab_chrom_bits[level+256]= uni_code;
          uni_DCtab_chrom_len [level+256]= uni_len;
  
      }
  }
  
  static void init_uni_mpeg4_rl_tab(RLTable *rl, uint32_t *bits_tab, uint8_t *len_tab){
      int slevel, run, last;
  
      assert(MAX_LEVEL >= 64);
      assert(MAX_RUN   >= 63);
  
      for(slevel=-64; slevel<64; slevel++){
          if(slevel==0) continue;
          for(run=0; run<64; run++){
              for(last=0; last<=1; last++){
                  const int index= UNI_MPEG4_ENC_INDEX(last, run, slevel+64);
                  int level= slevel < 0 ? -slevel : slevel;
                  int sign= slevel < 0 ? 1 : 0;
                  int bits, len, code;
                  int level1, run1;
  
                  len_tab[index]= 100;
  
                  /* ESC0 */
                  code= get_rl_index(rl, last, run, level);
                  bits= rl->table_vlc[code][0];
                  len=  rl->table_vlc[code][1];
                  bits=bits*2+sign; len++;
  
                  if(code!=rl->n && len < len_tab[index]){
                      bits_tab[index]= bits;
                      len_tab [index]= len;
                  }
                  /* ESC1 */
                  bits= rl->table_vlc[rl->n][0];
                  len=  rl->table_vlc[rl->n][1];
                  bits=bits*2;    len++; //esc1
                  level1= level - rl->max_level[last][run];
                  if(level1>0){
                      code= get_rl_index(rl, last, run, level1);
                      bits<<= rl->table_vlc[code][1];
                      len  += rl->table_vlc[code][1];
                      bits += rl->table_vlc[code][0];
                      bits=bits*2+sign; len++;
  
                      if(code!=rl->n && len < len_tab[index]){
                          bits_tab[index]= bits;
                          len_tab [index]= len;
                      }
                  }
                  /* ESC2 */
                  bits= rl->table_vlc[rl->n][0];
                  len=  rl->table_vlc[rl->n][1];
                  bits=bits*4+2;    len+=2; //esc2
                  run1 = run - rl->max_run[last][level] - 1;
                  if(run1>=0){
                      code= get_rl_index(rl, last, run1, level);
                      bits<<= rl->table_vlc[code][1];
                      len  += rl->table_vlc[code][1];
                      bits += rl->table_vlc[code][0];
                      bits=bits*2+sign; len++;
  
                      if(code!=rl->n && len < len_tab[index]){
                          bits_tab[index]= bits;
                          len_tab [index]= len;
                      }
                  }
                  /* ESC3 */
                  bits= rl->table_vlc[rl->n][0];
                  len = rl->table_vlc[rl->n][1];
                  bits=bits*4+3;    len+=2; //esc3
                  bits=bits*2+last; len++;
                  bits=bits*64+run; len+=6;
                  bits=bits*2+1;    len++;  //marker
                  bits=bits*4096+(slevel&0xfff); len+=12;
                  bits=bits*2+1;    len++;  //marker
  
                  if(len < len_tab[index]){
                      bits_tab[index]= bits;
                      len_tab [index]= len;
                  }
              }
          }
      }
  }
  
  static av_cold int encode_init(AVCodecContext *avctx)
  {
      MpegEncContext *s = avctx->priv_data;
      int ret;
      static int done = 0;
  
      if((ret=MPV_encode_init(avctx)) < 0)
          return ret;
  
      if (!done) {
          done = 1;
  
          init_uni_dc_tab();
  
          ff_init_rl(&ff_mpeg4_rl_intra, ff_mpeg4_static_rl_table_store[0]);
  
          init_uni_mpeg4_rl_tab(&ff_mpeg4_rl_intra, uni_mpeg4_intra_rl_bits, uni_mpeg4_intra_rl_len);
          init_uni_mpeg4_rl_tab(&ff_h263_rl_inter, uni_mpeg4_inter_rl_bits, uni_mpeg4_inter_rl_len);
      }
  
      s->min_qcoeff= -2048;
      s->max_qcoeff=  2047;
      s->intra_ac_vlc_length     = uni_mpeg4_intra_rl_len;
      s->intra_ac_vlc_last_length= uni_mpeg4_intra_rl_len + 128*64;
      s->inter_ac_vlc_length     = uni_mpeg4_inter_rl_len;
      s->inter_ac_vlc_last_length= uni_mpeg4_inter_rl_len + 128*64;
      s->luma_dc_vlc_length= uni_DCtab_lum_len;
      s->ac_esc_length= 7+2+1+6+1+12+1;
      s->y_dc_scale_table= ff_mpeg4_y_dc_scale_table;
      s->c_dc_scale_table= ff_mpeg4_c_dc_scale_table;
  
      if(s->flags & CODEC_FLAG_GLOBAL_HEADER){
  
          s->avctx->extradata= av_malloc(1024);
          init_put_bits(&s->pb, s->avctx->extradata, 1024);
  
          if(!(s->workaround_bugs & FF_BUG_MS))
              mpeg4_encode_visual_object_header(s);
          mpeg4_encode_vol_header(s, 0, 0);
  
  //            ff_mpeg4_stuffing(&s->pb); ?
          flush_put_bits(&s->pb);
          s->avctx->extradata_size= (put_bits_count(&s->pb)+7)>>3;
      }
      return 0;
  }
  
  void ff_mpeg4_init_partitions(MpegEncContext *s)
  {
      uint8_t *start= put_bits_ptr(&s->pb);
      uint8_t *end= s->pb.buf_end;
      int size= end - start;
      int pb_size = (((intptr_t)start + size/3)&(~3)) - (intptr_t)start;
      int tex_size= (size - 2*pb_size)&(~3);
  
      set_put_bits_buffer_size(&s->pb, pb_size);
      init_put_bits(&s->tex_pb, start + pb_size           , tex_size);
      init_put_bits(&s->pb2   , start + pb_size + tex_size, pb_size);
  }
  
  void ff_mpeg4_merge_partitions(MpegEncContext *s)
  {
      const int pb2_len   = put_bits_count(&s->pb2   );
      const int tex_pb_len= put_bits_count(&s->tex_pb);
      const int bits= put_bits_count(&s->pb);
  
      if(s->pict_type==AV_PICTURE_TYPE_I){
          put_bits(&s->pb, 19, DC_MARKER);
          s->misc_bits+=19 + pb2_len + bits - s->last_bits;
          s->i_tex_bits+= tex_pb_len;
      }else{
          put_bits(&s->pb, 17, MOTION_MARKER);
          s->misc_bits+=17 + pb2_len;
          s->mv_bits+= bits - s->last_bits;
          s->p_tex_bits+= tex_pb_len;
      }
  
      flush_put_bits(&s->pb2);
      flush_put_bits(&s->tex_pb);
  
      set_put_bits_buffer_size(&s->pb, s->pb2.buf_end - s->pb.buf);
      avpriv_copy_bits(&s->pb, s->pb2.buf   , pb2_len);
      avpriv_copy_bits(&s->pb, s->tex_pb.buf, tex_pb_len);
      s->last_bits= put_bits_count(&s->pb);
  }
  
  
  void ff_mpeg4_encode_video_packet_header(MpegEncContext *s)
  {
      int mb_num_bits= av_log2(s->mb_num - 1) + 1;
  
      put_bits(&s->pb, ff_mpeg4_get_video_packet_prefix_length(s), 0);
      put_bits(&s->pb, 1, 1);
  
      put_bits(&s->pb, mb_num_bits, s->mb_x + s->mb_y*s->mb_width);
      put_bits(&s->pb, s->quant_precision, s->qscale);
      put_bits(&s->pb, 1, 0); /* no HEC */
  }
  
  #define OFFSET(x) offsetof(MpegEncContext, x)
  #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
  static const AVOption options[] = {
      { "data_partitioning",       "Use data partitioning.",      OFFSET(data_partitioning), AV_OPT_TYPE_INT, { 0 }, 0, 1, VE },
      { "alternate_scan",          "Enable alternate scantable.", OFFSET(alternate_scan),    AV_OPT_TYPE_INT, { 0 }, 0, 1, VE },
      { NULL },
  };
  
  static const AVClass mpeg4enc_class = {
      .class_name = "MPEG4 encoder",
      .item_name  = av_default_item_name,
      .option     = options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  AVCodec ff_mpeg4_encoder = {
      .name           = "mpeg4",
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = CODEC_ID_MPEG4,
      .priv_data_size = sizeof(MpegEncContext),
      .init           = encode_init,
      .encode         = MPV_encode_picture,
      .close          = MPV_encode_end,
      .pix_fmts= (const enum PixelFormat[]){PIX_FMT_YUV420P, PIX_FMT_NONE},
      .capabilities= CODEC_CAP_DELAY | CODEC_CAP_SLICE_THREADS,
      .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
      .priv_class     = &mpeg4enc_class,
  };
  