text: /*
   * MPEG-4 encoder
   * Copyright (c) 2000,2001 Fabrice Bellard
   * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "libavutil/attributes.h"
  #include "libavutil/log.h"
  #include "libavutil/opt.h"
  #include "libavutil/thread.h"
  #include "mpegutils.h"
  #include "mpegvideo.h"
  #include "h263.h"
  #include "mpeg4video.h"
  #include "profiles.h"
  
  /* The uni_DCtab_* tables below contain unified bits+length tables to encode DC
   * differences in MPEG-4. 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))
  
  /* MPEG-4
   * 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, int16_t 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 referring to the last non zero coefficient in zigzag order
   */
  static inline void restore_ac_coeffs(MpegEncContext *s, int16_t 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][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->idsp.idct_permutation[i]] = ac_val[i + 8];
          } else {
              /* left prediction */
              for (i = 1; i < 8; i++)
                  block[n][s->idsp.idct_permutation[i << 3]] = ac_val[i];
          }
      }
  }
  
  /**
   * Return the optimal value (0 or 1) for the ac_pred element for the given MB in MPEG-4.
   * 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 referring to the last non zero coefficient in zigzag order
   */
  static inline int decide_ac_pred(MpegEncContext *s, int16_t 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.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][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->idsp.idct_permutation[i]];
                      block[n][s->idsp.idct_permutation[i]] = level - ac_val[i + 8];
                      ac_val1[i]     = block[n][s->idsp.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->idsp.idct_permutation[i]];
                      block[n][s->idsp.idct_permutation[i]] = level - ROUNDED_DIV(ac_val[i + 8] * qscale_table[xy], s->qscale);
                      ac_val1[i]     = block[n][s->idsp.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->idsp.idct_permutation[i << 3]];
                      block[n][s->idsp.idct_permutation[i << 3]] = level - ac_val[i];
                      ac_val1[i]     = level;
                      ac_val1[i + 8] = block[n][s->idsp.idct_permutation[i]];
                  }
              } else {
                  /* different qscale, we must rescale */
                  for (i = 1; i < 8; i++) {
                      const int level = block[n][s->idsp.idct_permutation[i << 3]];
                      block[n][s->idsp.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->idsp.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 actually possible in MPEG-4
   */
  void ff_clean_mpeg4_qscales(MpegEncContext *s)
  {
      int i;
      int8_t *const qscale_table = s->current_picture.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 MPEG-4 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)
  {
      /* 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]);
      }
  }
  
  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,
                                        int16_t *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
          /* MPEG-4 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,
                                    int16_t *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
          /* MPEG-4 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, int16_t block[6][64],
                                         int intra_dc[6], uint8_t **scan_table,
                                         PutBitContext *dc_pb,
                                         PutBitContext *ac_pb)
  {
      int i;
  
      if (scan_table) {
          if (s->avctx->flags2 & AV_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->avctx->flags2 & AV_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, int16_t block[6][64],
                              int motion_x, int motion_y, int mb_type)
  {
      int cbp = 0, i;
  
      if (s->mpv_flags & FF_MPV_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->bdsp.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 ff_mpeg4_encode_mb(MpegEncContext *s, int16_t 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->avctx->flags & AV_CODEC_FLAG_PASS1) && !s->data_partitioning ? 1 : 0;
  
      if (!s->mb_intra) {
          int i, cbp;
  
          if (s->pict_type == AV_PICTURE_TYPE_B) {
              /* convert from mv_dir to type */
              static const int mb_type_table[8] = { -1, 3, 2, 1, -1, -1, -1, 0 };
              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;
              }
  
              av_assert2(s->dquant >= -2 && s->dquant <= 2);
              av_assert2((s->dquant & 1) == 0);
              av_assert2(mb_type >= 0);
  
              /* nothing to do if this MB was skipped in the next P-frame */
              if (s->next_picture.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} */
                  av_assert2(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) {
                  av_assert2(s->mv_dir & MV_DIRECT);
                  ff_h263_encode_motion_vector(s, motion_x, motion_y, 1);
                  s->b_count++;
                  s->f_count++;
              } else {
                  av_assert2(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;
  
                      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 || pic->f->pict_type != AV_PICTURE_TYPE_B)
                              break;
  
                          b_pic = pic->f->data[0] + offset;
                          if (!pic->shared)
                              b_pic += INPLACE_OFFSET;
  
                          if (x + 16 > s->width || y + 16 > s->height) {
                              int x1, y1;
                              int xe = FFMIN(16, s->width - x);
                              int ye = FFMIN(16, s->height - y);
                              diff = 0;
                              for (y1 = 0; y1 < ye; y1++) {
                                  for (x1 = 0; x1 < xe; x1++) {
                                      diff += FFABS(p_pic[x1 + y1 * s->linesize] - b_pic[x1 + y1 * s->linesize]);
                                  }
                              }
                              diff = diff * 256 / (xe * ye);
                          } else {
                              diff = s->mecc.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]);
  
                  av_assert2(!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 {
                  av_assert2(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 && 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.motion_val[0][s->block_index[i]][0] - pred_x,
                                                   s->current_picture.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->avctx->flags & AV_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 MPEG-4 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      = FFUDIV(s->time, s->avctx->time_base.den);
      }
  }
  
  static void mpeg4_encode_gop_header(MpegEncContext *s)
  {
      int64_t 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;
      s->last_time_base = FFUDIV(time, s->avctx->time_base.den);
  
      seconds = FFUDIV(time, s->avctx->time_base.den);
      minutes = FFUDIV(seconds, 60); seconds = FFUMOD(seconds, 60);
      hours   = FFUDIV(minutes, 60); minutes = FFUMOD(minutes, 60);
      hours   = FFUMOD(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->avctx->flags & AV_CODEC_FLAG_CLOSED_GOP));
      put_bits(&s->pb, 1, 0);  // broken link == NO
  
      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 (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) {
          av_reduce(&s->avctx->sample_aspect_ratio.num, &s->avctx->sample_aspect_ratio.den,
                     s->avctx->sample_aspect_ratio.num,  s->avctx->sample_aspect_ratio.den, 255);
          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, 0);       /* sprite enable */
      else
          put_bits(&s->pb, 2, 0);       /* sprite enable */
  
      put_bits(&s->pb, 1, 0);             /* not 8 bit == false */
      put_bits(&s->pb, 1, s->mpeg_quant); /* quant type = (0 = H.263 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 */
      put_bits(&s->pb, 1, s->rtp_mode ? 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->avctx->flags & AV_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 MPEG-4 VOP header */
  int ff_mpeg4_encode_picture_header(MpegEncContext *s, int picture_number)
  {
      uint64_t time_incr;
      int64_t time_div, time_mod;
  
      if (s->pict_type == AV_PICTURE_TYPE_I) {
          if (!(s->avctx->flags & AV_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 */
  
      time_div  = FFUDIV(s->time, s->avctx->time_base.den);
      time_mod  = FFUMOD(s->time, s->avctx->time_base.den);
      time_incr = time_div - s->last_time_base;
  
      // This limits the frame duration to max 1 hour
      if (time_incr > 3600) {
          av_log(s->avctx, AV_LOG_ERROR, "time_incr %"PRIu64" too large\n", time_incr);
          return AVERROR(EINVAL);
      }
      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) {
          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 */
  
      return 0;
  }
  
  static av_cold 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 av_cold void init_uni_mpeg4_rl_tab(RLTable *rl, uint32_t *bits_tab,
                                            uint8_t *len_tab)
  {
      int slevel, run, last;
  
      av_assert0(MAX_LEVEL >= 64);
      av_assert0(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 void mpeg4_encode_init_static(void)
  {
      init_uni_dc_tab();
  
      ff_mpeg4_init_rl_intra();
  
      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);
  }
  
  static av_cold int encode_init(AVCodecContext *avctx)
  {
      static AVOnce init_static_once = AV_ONCE_INIT;
      MpegEncContext *s = avctx->priv_data;
      int ret;
  
      if (avctx->width >= (1<<13) || avctx->height >= (1<<13)) {
          av_log(avctx, AV_LOG_ERROR, "dimensions too large for MPEG-4\n");
          return AVERROR(EINVAL);
      }
  
      if ((ret = ff_mpv_encode_init(avctx)) < 0)
          return ret;
  
      ff_thread_once(&init_static_once, mpeg4_encode_init_static);
  
      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->avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER) {
          s->avctx->extradata = av_malloc(1024);
          if (!s->avctx->extradata)
              return AVERROR(ENOMEM);
          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_bytes_output(&s->pb);
      }
      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);
      ff_copy_bits(&s->pb, s->pb2.buf, pb2_len);
      ff_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_BOOL, { .i64 = 0 }, 0, 1, VE },
      { "alternate_scan",    "Enable alternate scantable.", OFFSET(alternate_scan),    AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VE },
      { "mpeg_quant",        "Use MPEG quantizers instead of H.263",
        OFFSET(mpeg_quant), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, VE },
      FF_MPV_COMMON_BFRAME_OPTS
      FF_MPV_COMMON_OPTS
  #if FF_API_MPEGVIDEO_OPTS
      FF_MPV_DEPRECATED_A53_CC_OPT
      FF_MPV_DEPRECATED_MATRIX_OPT
  #endif
      FF_MPEG4_PROFILE_OPTS
      { NULL },
  };
  
  static const AVClass mpeg4enc_class = {
      .class_name = "MPEG4 encoder",
      .item_name  = av_default_item_name,
      .option     = options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  const AVCodec ff_mpeg4_encoder = {
      .name           = "mpeg4",
      .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_MPEG4,
      .priv_data_size = sizeof(MpegEncContext),
      .init           = encode_init,
      .encode2        = ff_mpv_encode_picture,
      .close          = ff_mpv_encode_end,
      .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE },
      .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_SLICE_THREADS,
      .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
      .priv_class     = &mpeg4enc_class,
  };
  