vid_stream->slice.extra_info = get_extra_bit_info(vid_stream);  /* Reset past intrablock address. */  vid_stream->mblock.past_intra_addr = -2;  /* Reset previous recon motion vectors. */  vid_stream->mblock.recon_right_for_prev = 0;  vid_stream->mblock.recon_down_for_prev = 0;  vid_stream->mblock.recon_right_back_prev = 0;  vid_stream->mblock.recon_down_back_prev = 0;  /* Reset macroblock address. */  vid_stream->mblock.mb_address = ((vid_stream->slice.vert_pos - 1) *                                   vid_stream->mb_width) - 1;  /* Reset past dct dc y, cr, and cb values. */#ifdef USE_ATI  vid_stream->block.dct_dc_y_past = 0;  vid_stream->block.dct_dc_cr_past = 0;  vid_stream->block.dct_dc_cb_past = 0;#else  vid_stream->block.dct_dc_y_past = 1024 << 3;  vid_stream->block.dct_dc_cr_past = 1024 << 3;  vid_stream->block.dct_dc_cb_past = 1024 << 3;#endif  return PARSE_OK;}/* *-------------------------------------------------------------- * * ParseMacroBlock -- * *      Parseoff macroblock. Reconstructs DCT values. Applies *      inverse DCT, reconstructs motion vectors, calculates and *      set pixel values for macroblock in current pict image *      structure. * * Results: *      Here's where everything really happens. Welcome to the *      heart of darkness. * * Side effects: *      Bit stream irreversibly parsed off. * *-------------------------------------------------------------- */static int ParseMacroBlock( VidStream* vid_stream ){  int addr_incr;  unsigned int data;  int mask, i, recon_right_for, recon_down_for, recon_right_back,      recon_down_back;  int zero_block_flag;  BOOLEAN mb_quant = 0, mb_motion_forw = 0, mb_motion_back = 0,       mb_pattern = 0;#ifndef DISABLE_DITHER  int no_dith_flag = 0;  int ditherType = vid_stream->ditherType;#endif#ifdef ANALYSIS  mbSizeCount = bitCountRead();#endif#ifdef USE_ATI  /* Empty macroblock */  vid_stream->block.dct_recon[0][0] = 0xFFFFFFFF;  vid_stream->block.dct_recon[1][0] = 0xFFFFFFFF;  vid_stream->block.dct_recon[2][0] = 0xFFFFFFFF;  vid_stream->block.dct_recon[3][0] = 0xFFFFFFFF;  vid_stream->block.dct_recon[4][0] = 0xFFFFFFFF;  vid_stream->block.dct_recon[5][0] = 0xFFFFFFFF;#endif  /*   * Parse off macroblock address increment and add to macroblock address.   */  do  {    unsigned int ind;    show_bits11(ind);    DecodeMBAddrInc(addr_incr);    if (mb_addr_inc[ind].num_bits==0)    {      addr_incr = 1;    }    if (addr_incr == MB_ESCAPE)    {      vid_stream->mblock.mb_address += 33;      addr_incr = MB_STUFFING;    }  } while (addr_incr == MB_STUFFING);  vid_stream->mblock.mb_address += addr_incr;  if( vid_stream->mblock.mb_address > (int) (vid_stream->mb_height *                                       vid_stream->mb_width - 1) )    return SKIP_TO_START_CODE;  /*   * If macroblocks have been skipped, process skipped macroblocks.   */  if (vid_stream->mblock.mb_address - vid_stream->mblock.past_mb_addr > 1) {    if (vid_stream->picture.code_type == P_TYPE)      ProcessSkippedPFrameMBlocks(vid_stream);    else if (vid_stream->picture.code_type == B_TYPE)      ProcessSkippedBFrameMBlocks(vid_stream);  }  /* Set past macroblock address to current macroblock address. */  vid_stream->mblock.past_mb_addr = vid_stream->mblock.mb_address;  /* Based on picture type decode macroblock type. */  switch (vid_stream->picture.code_type) {  case I_TYPE:    DecodeMBTypeI(mb_quant, mb_motion_forw, mb_motion_back, mb_pattern,                  vid_stream->mblock.mb_intra);    break;  case P_TYPE:    DecodeMBTypeP(mb_quant, mb_motion_forw, mb_motion_back, mb_pattern,                  vid_stream->mblock.mb_intra);    break;  case B_TYPE:    DecodeMBTypeB(mb_quant, mb_motion_forw, mb_motion_back, mb_pattern,                  vid_stream->mblock.mb_intra);    break;  case D_TYPE:    fprintf(stderr, "ERROR:  MPEG-1 Streams with D-frames are not supported\n");    exit(1);  }  /* If quantization flag set, parse off new quantization scale. */  if (mb_quant == TRUE) {    get_bits5(data);    vid_stream->slice.quant_scale = data;  }  /* If forward motion vectors exist... */  if (mb_motion_forw == TRUE) {    /* Parse off and decode horizontal forward motion vector. */    DecodeMotionVectors(vid_stream->mblock.motion_h_forw_code);    /* If horiz. forward r data exists, parse off. */    if ((vid_stream->picture.forw_f != 1) &&        (vid_stream->mblock.motion_h_forw_code != 0)) {      get_bitsn(vid_stream->picture.forw_r_size, data);      vid_stream->mblock.motion_h_forw_r = data;    }    /* Parse off and decode vertical forward motion vector. */    DecodeMotionVectors(vid_stream->mblock.motion_v_forw_code);    /* If vert. forw. r data exists, parse off. */    if ((vid_stream->picture.forw_f != 1) &&        (vid_stream->mblock.motion_v_forw_code != 0)) {      get_bitsn(vid_stream->picture.forw_r_size, data);      vid_stream->mblock.motion_v_forw_r = data;    }  }  /* If back motion vectors exist... */  if (mb_motion_back == TRUE) {    /* Parse off and decode horiz. back motion vector. */    DecodeMotionVectors(vid_stream->mblock.motion_h_back_code);    /* If horiz. back r data exists, parse off. */    if ((vid_stream->picture.back_f != 1) &&        (vid_stream->mblock.motion_h_back_code != 0)) {      get_bitsn(vid_stream->picture.back_r_size, data);      vid_stream->mblock.motion_h_back_r = data;    }    /* Parse off and decode vert. back motion vector. */    DecodeMotionVectors(vid_stream->mblock.motion_v_back_code);    /* If vert. back r data exists, parse off. */    if ((vid_stream->picture.back_f != 1) &&        (vid_stream->mblock.motion_v_back_code != 0)) {      get_bitsn(vid_stream->picture.back_r_size, data);      vid_stream->mblock.motion_v_back_r = data;    }  }#ifdef ANALYSIS  if (vid_stream->mblock.mb_intra) {    stat_a[0].i_mbnum++;    mbCBPPtr = stat_a[0].i_mbcbp;    mbCoeffPtr = stat_a[0].i_mbcoeff;    mbSizePtr = &(stat_a[0].i_mbsize);  } else if (mb_motion_back && mb_motion_forw) {    stat_a[0].bi_mbnum++;    mbCBPPtr = stat_a[0].bi_mbcbp;    mbCoeffPtr = stat_a[0].bi_mbcoeff;    mbSizePtr = &(stat_a[0].bi_mbsize);  } else if (mb_motion_back) {    stat_a[0].b_mbnum++;    mbCBPPtr = stat_a[0].b_mbcbp;    mbCoeffPtr = stat_a[0].b_mbcoeff;    mbSizePtr = &(stat_a[0].b_mbsize);  } else {    stat_a[0].p_mbnum++;    mbCBPPtr = stat_a[0].p_mbcbp;    mbCoeffPtr = stat_a[0].p_mbcoeff;    mbSizePtr = &(stat_a[0].p_mbsize);  }#endif  /* If mblock pattern flag set, parse and decode CBP (code block pattern). */  if (mb_pattern == TRUE) {    DecodeCBP(vid_stream->mblock.cbp);  }  /* Otherwise, set CBP to zero. */  else    vid_stream->mblock.cbp = 0;#ifdef ANALYSIS  mbCBPPtr[vid_stream->mblock.cbp]++;#endif  /* Reconstruct motion vectors depending on picture type. */  if (vid_stream->picture.code_type == P_TYPE) {    /*     * If no forw motion vectors, reset previous and current vectors to 0.     */    if (!mb_motion_forw) {      recon_right_for = 0;      recon_down_for = 0;      vid_stream->mblock.recon_right_for_prev = 0;      vid_stream->mblock.recon_down_for_prev = 0;    }    /*     * Otherwise, compute new forw motion vectors. Reset previous vectors to     * current vectors.     */    else {      ComputeForwVector(&recon_right_for, &recon_down_for, vid_stream);    }  }  if (vid_stream->picture.code_type == B_TYPE) {    /* Reset prev. and current vectors to zero if mblock is intracoded. */    if (vid_stream->mblock.mb_intra) {      vid_stream->mblock.recon_right_for_prev = 0;      vid_stream->mblock.recon_down_for_prev = 0;      vid_stream->mblock.recon_right_back_prev = 0;      vid_stream->mblock.recon_down_back_prev = 0;    } else {            /* If no forw vectors, current vectors equal prev. vectors. */            if (!mb_motion_forw) {        recon_right_for = vid_stream->mblock.recon_right_for_prev;        recon_down_for = vid_stream->mblock.recon_down_for_prev;      }      /*       * Otherwise compute forw. vectors. Reset prev vectors to new values.       */            else {        ComputeForwVector(&recon_right_for, &recon_down_for, vid_stream);      }            /* If no back vectors, set back vectors to prev back vectors. */            if (!mb_motion_back) {        recon_right_back = vid_stream->mblock.recon_right_back_prev;        recon_down_back = vid_stream->mblock.recon_down_back_prev;      }      /* Otherwise compute new vectors and reset prev. back vectors. */      else {        ComputeBackVector(&recon_right_back, &recon_down_back, vid_stream);      }      /*       * Store vector existence flags in structure for possible skipped       * macroblocks to follow.       */      vid_stream->mblock.bpict_past_forw = mb_motion_forw;      vid_stream->mblock.bpict_past_back = mb_motion_back;    }  }#ifndef DISABLE_DITHER  /* For each possible block in macroblock. */  if (ditherType == GRAY_DITHER ||      ditherType == GRAY2_DITHER ||      ditherType == GRAY256_DITHER ||      ditherType == GRAY2562_DITHER ||      ditherType == MONO_DITHER ||      ditherType == MONO_THRESHOLD) {    for (mask = 32, i = 0; i < 4; mask >>= 1, i++) {      /* If block exists... */      if ((vid_stream->mblock.mb_intra) || (vid_stream->mblock.cbp & mask)) {        zero_block_flag = 0;        ParseReconBlock(i, vid_stream);      } else {        zero_block_flag = 1;      }      /* If macroblock is intra coded... */      if (vid_stream->mblock.mb_intra) {        ReconIMBlock(vid_stream, i);      } else if (mb_motion_forw && mb_motion_back) {        ReconBiMBlock(vid_stream, i, recon_right_for, recon_down_for,                    recon_right_back, recon_down_back, zero_block_flag);      } else if (mb_motion_forw || (vid_stream->picture.code_type == P_TYPE)) {        ReconPMBlock(vid_stream, i, recon_right_for, recon_down_for,                    zero_block_flag);      } else if (mb_motion_back) {        ReconBMBlock(vid_stream, i, recon_right_back, recon_down_back,                    zero_block_flag);      }    }    /* Kill the Chrominance blocks... */    if ((vid_stream->mblock.mb_intra) || (vid_stream->mblock.cbp & 0x2)) {        ParseAwayBlock(4, vid_stream);    }    if ((vid_stream->mblock.mb_intra) || (vid_stream->mblock.cbp & 0x1)) {        ParseAwayBlock(5, vid_stream);    }  } else {    if ((ditherType == MBORDERED_DITHER) &&        (vid_stream->mblock.cbp == 0) &&        (vid_stream->picture.code_type == 3) &&        (!vid_stream->mblock.mb_intra) &&        (!(mb_motion_forw && mb_motion_back))) {      MBOrderedDitherDisplayCopy(vid_stream, vid_stream->mblock.mb_address,                      mb_motion_forw, recon_right_for, recon_down_for,                      mb_motion_back, recon_right_back, recon_down_back,                     vid_stream->past->display, vid_stream->future->display);      vid_stream->ditherFlags[vid_stream->mblock.mb_address] = 0;      no_dith_flag = 1;    }    else {#endif      for (mask = 32, i = 0; i < 6; mask >>= 1, i++) {                /* If block exists... */        if ((vid_stream->mblock.mb_intra) || (vid_stream->mblock.cbp & mask)) {          zero_block_flag = 0;          ParseReconBlock(i, vid_stream);        } else {          zero_block_flag = 1;        }#ifndef USE_ATI        /* If macroblock is intra coded... */        if (vid_stream->mblock.mb_intra) {          ReconIMBlock(vid_stream, i);        } else if (mb_motion_forw && mb_motion_back) {          ReconBiMBlock(vid_stream, i, recon_right_for, recon_down_for,                        recon_right_back, recon_down_back, zero_block_flag);        } else if (mb_motion_forw || (vid_stream->picture.code_type == P_TYPE)) {          ReconPMBlock(vid_stream, i, recon_right_for, recon_down_for,                       zero_block_flag);        } else if (mb_motion_back) {          ReconBMBlock(vid_stream, i, recon_right_back, recon_down_back,                       zero_block_flag);        }#endif      }#ifdef USE_ATI      vhar128_macroblock(vid_stream->ati_handle,			 (vid_stream->mblock.mb_address % vid_stream->mb_width) << 4,			 (vid_stream->mblock.mb_address / vid_stream->mb_width) << 4,			 vid_stream->mblock.mb_intra,			 mb_motion_back, mb_motion_forw,			 recon_right_back, recon_down_back,			 recon_right_for, recon_down_for,			 vid_stream->block.dct_recon);#endif#ifndef DISABLE_DITHER    }  }#endif#ifndef DISABLE_DITHER  if ((ditherType == MBORDERED_DITHER) && (!no_dith_flag)) {    if ((vid_stream->picture.code_type == 2) &&        (vid_stream->mblock.cbp == 0) &&        (!vid_stream->mblock.mb_intra)) {      MBOrderedDitherDisplayCopy(vid_stream, vid_stream->mblock.mb_address,                                 1, recon_right_for, recon_down_for,                                 0, 0, 0,                                 vid_stream->future->display,                                 (unsigned char *) NULL);      vid_stream->ditherFlags[vid_stream->mblock.mb_address] = 0;    }    else {      vid_stream->ditherFlags[vid_stream->mblock.mb_address] = 1;    }  }#endif  /* If D Type picture, flush marker bit. */  if (vid_stream->picture.code_type == 4)    flush_bits(1);  /* If macroblock was intracoded, set macroblock past intra address. */  if (vid_stream->mblock.mb_intra)    vid_stream->mblock.past_intra_addr =      vid_stream->mblock.mb_address;  /* Store macroblock error for filter info */  if (vid_stream->mblock.mb_intra)    vid_stream->current->mb_qscale[vid_stream->mblock.mb_address] = 0;  else    vid_stream->current->mb_qscale[vid_stream->mblock.mb_address] = vid_stream->slice.quant_scale;#ifdef ANALYSIS  *mbSizePtr += bitCountRead() - mbSizeCount;#endif  return PARSE_OK;}/* software decoder follows */#ifndef USE_ATI/* *-------------------------------------------------------------- * * ReconIMBlock -- * *        Reconstructs intra coded macroblock. * * Results: *        None. * * Side effects: *        None. * *-------------------------------------------------------------- */#if defined(USE_CROP_TABLE) && !defined(NDEBUG)/* If people really