video.cpp

This code is based on mpeg_play, available from: http://bmrc.berkeley.edu/frame/research/mpeg/

  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