video.c

MPEG2 PLAYER in linux

   * Initialize ring buffer of pict images now that dimensions of image space
   * are known.
   */

#ifdef SH_MEM
  if (xinfo->display != NULL) {
    InstallXErrorHandler(xinfo->display);
  }
#endif

  if (vid_stream->ring[0] == NULL) {
    for (i = 0; i < RING_BUF_SIZE; i++) {
      vid_stream->ring[i] = NewPictImage(vid_stream,xinfo);
    }
  }
#ifdef SH_MEM
  if (xinfo->display != NULL) {
    DeInstallXErrorHandler(xinfo->display);
  }
#endif

  /* Parse of aspect ratio code. */

  get_bits4(data);
  vid_stream->aspect_ratio = (unsigned char) data;

  /* Parse off picture rate code. */

  get_bits4(data);
  vid_stream->picture_rate = (unsigned char) data;

  /* Parse off bit rate. */

  get_bits18(data);
  vid_stream->bit_rate = data;

  /* Flush marker bit. */

  flush_bits(1);

  /* Parse off vbv buffer size. */

  get_bits10(data);
  vid_stream->vbv_buffer_size = data;

#ifdef not_def
  /* Lets not bother with this.  Only increases memory image */
  if (data*1024>vid_stream->max_buf_length) {
    unsigned int *newbuf;
    int sz=1024*data+1;
    /* If they actually want a bigger buffer than we default to,
       let them have it! (if we can) */
    newbuf = (unsigned int *) realloc(vid_stream->buf_start, (unsigned int) 4*sz);
    if (newbuf!=(unsigned int *)NULL) {
      vid_stream->max_buf_length=sz;
      vid_stream->buffer=
	  (vid_stream->buffer-vid_stream->buf_start)+newbuf;
      vid_stream->buf_start=newbuf;
    }}
#endif

  /* Parse off contrained parameter flag. */

  get_bits1(data);
  if (data) {
    vid_stream->const_param_flag = TRUE;
  } else
    vid_stream->const_param_flag = FALSE;

  /*
   * If intra_quant_matrix_flag set, parse off intra quant matrix values.
   */

  get_bits1(data);
  if (data) {
    for (i = 0; i < 64; i++) {
      get_bits8(data);

      vid_stream->intra_quant_matrix[zigzag[i][1]][zigzag[i][0]] =
	(unsigned char) data;
    }
  }
  /*
   * If non intra quant matrix flag set, parse off non intra quant matrix
   * values.
   */

  get_bits1(data);
  if (data) {
    for (i = 0; i < 64; i++) {
      get_bits8(data);

      vid_stream->non_intra_quant_matrix[zigzag[i][1]][zigzag[i][0]] =
	(unsigned char) data;
    }
  }
  /* Go to next start code. */

  next_start_code(vid_stream);

  /*
   * If next start code is extension start code, parse off extension data.
   */

  if (next_bits(32, EXT_START_CODE, vid_stream)) {
    flush_bits32;
    if (vid_stream->ext_data != NULL) {
      free(vid_stream->ext_data);
      vid_stream->ext_data = NULL;
    }
    vid_stream->ext_data = get_ext_data(vid_stream);
  }
  /* If next start code is user start code, parse off user data. */

  if (next_bits(32, USER_START_CODE, vid_stream)) {
    flush_bits32;
    if (vid_stream->user_data != NULL) {
      free(vid_stream->user_data);
      vid_stream->user_data = NULL;
    }
    vid_stream->user_data = get_ext_data(vid_stream);
  }
  return PARSE_OK;
}



/*
 *--------------------------------------------------------------
 *
 * ParseGOP --
 *
 *      Parses of group of pictures header from bit stream
 *      associated with vid_stream.
 *
 * Results:
 *      Values in gop header placed into video stream structure.
 *
 * Side effects:
 *      Bit stream irreversibly parsed.
 *
 *--------------------------------------------------------------
 */

static int
ParseGOP(vid_stream)
  VidStream *vid_stream;
{
  unsigned int data;

  /* Flush group of pictures start code. */

  flush_bits32;

  /* Parse off drop frame flag. */

  get_bits1(data);
  if (data) {
    vid_stream->group.drop_flag = TRUE;
  } else
    vid_stream->group.drop_flag = FALSE;

  /* Parse off hour component of time code. */

  get_bits5(data);
  vid_stream->group.tc_hours = data;

  /* Parse off minute component of time code. */

  get_bits6(data);
  vid_stream->group.tc_minutes = data;

  /* Flush marker bit. */

  flush_bits(1);

  /* Parse off second component of time code. */

  get_bits6(data);
  vid_stream->group.tc_seconds = data;

  /* Parse off picture count component of time code. */

  get_bits6(data);
  vid_stream->group.tc_pictures = data;

  /* Parse off closed gop and broken link flags. */

  get_bits2(data);
  if (data > 1) {
    vid_stream->group.closed_gop = TRUE;
    if (data > 2) {
      vid_stream->group.broken_link = TRUE;
    } else
      vid_stream->group.broken_link = FALSE;
  } else {
    vid_stream->group.closed_gop = FALSE;
    if (data) {
      vid_stream->group.broken_link = TRUE;
    } else
      vid_stream->group.broken_link = FALSE;
  }

  /* Goto next start code. */

  next_start_code(vid_stream);

  /* If next start code is extension data, parse off extension data. */

  if (next_bits(32, EXT_START_CODE, vid_stream)) {
    flush_bits32;
    if (vid_stream->group.ext_data != NULL) {
      free(vid_stream->group.ext_data);
      vid_stream->group.ext_data = NULL;
    }
    vid_stream->group.ext_data = get_ext_data(vid_stream);
  }
  /* If next start code is user data, parse off user data. */

  if (next_bits(32, USER_START_CODE,vid_stream)) {
    flush_bits32;
    if (vid_stream->group.user_data != NULL) {
      free(vid_stream->group.user_data);
      vid_stream->group.user_data = NULL;
    }
    vid_stream->group.user_data = get_ext_data(vid_stream);
  }
  return PARSE_OK;
}



/*
 *--------------------------------------------------------------
 *
 * ParsePicture --
 *
 *      Parses picture header. Marks picture to be presented
 *      at particular time given a time stamp.
 *
 * Results:
 *      Values from picture header put into video stream structure.
 *
 * Side effects:
 *      Bit stream irreversibly parsed.
 *
 *--------------------------------------------------------------
 */

static int
ParsePicture(vid_stream, time_stamp)
  VidStream *vid_stream;
  TimeStamp time_stamp;
{
  unsigned int data;
  int i;

  /* Flush header start code. */
  flush_bits32;

  /* Parse off temporal reference. */
  get_bits10(data);
  vid_stream->picture.temp_ref = data;

  /* Parse of picture type. */
  get_bits3(data);
  vid_stream->picture.code_type = data;

  if ((vid_stream->picture.code_type == B_TYPE) &&
      (/* No_B_Flag || */
       (vid_stream->future == NULL) ||
       ((vid_stream->past == NULL) && !(vid_stream->group.closed_gop))))
    /* According to 2-D.5.1 (p D-18) this is ok, if the refereneces are OK */
    return SKIP_PICTURE;

  if ((vid_stream->picture.code_type == P_TYPE) &&
      (No_P_Flag || (vid_stream->future == NULL)))
    return SKIP_PICTURE;

#ifdef ANALYSIS
  StartTime();
  stat_a[0].frametype = vid_stream->picture.code_type;
  stat_a[0].number = 1;
  stat_a[0].totsize = 45;
  pictureSizeCount = bitCountRead();
#endif

  /* Parse off vbv buffer delay value. */
  get_bits16(data);
  vid_stream->picture.vbv_delay = data;

  /* If P or B type frame... */

  if ((vid_stream->picture.code_type == P_TYPE) || 
      (vid_stream->picture.code_type == B_TYPE)) {

    /* Parse off forward vector full pixel flag. */
    get_bits1(data);
    if (data) {
      vid_stream->picture.full_pel_forw_vector = TRUE;
    } else {
      vid_stream->picture.full_pel_forw_vector = FALSE;
    }

    /* Parse of forw_r_code. */
    get_bits3(data);

    /* Decode forw_r_code into forw_r_size and forw_f. */

    vid_stream->picture.forw_r_size = data - 1;
    vid_stream->picture.forw_f = (1 << vid_stream->picture.forw_r_size);
  }
  /* If B type frame... */

  if (vid_stream->picture.code_type == B_TYPE) {

    /* Parse off back vector full pixel flag. */
    get_bits1(data);
    if (data)
      vid_stream->picture.full_pel_back_vector = TRUE;
    else
      vid_stream->picture.full_pel_back_vector = FALSE;

    /* Parse off back_r_code. */
    get_bits3(data);

    /* Decode back_r_code into back_r_size and back_f. */

    vid_stream->picture.back_r_size = data - 1;
    vid_stream->picture.back_f = (1 << vid_stream->picture.back_r_size);
  }
  /* Get extra bit picture info. */

  if (vid_stream->picture.extra_info != NULL) {
    free(vid_stream->picture.extra_info);
    vid_stream->picture.extra_info = NULL;
  }
  vid_stream->picture.extra_info = get_extra_bit_info(vid_stream);

  /* Goto next start code. */
  next_start_code(vid_stream);

  /* If start code is extension start code, parse off extension data. */

  if (next_bits(32, EXT_START_CODE, vid_stream)) {
    flush_bits32;

    if (vid_stream->picture.ext_data != NULL) {
      free(vid_stream->picture.ext_data);
      vid_stream->picture.ext_data = NULL;
    }
    vid_stream->picture.ext_data = get_ext_data(vid_stream);
  }
  /* If start code is user start code, parse off user data. */

  if (next_bits(32, USER_START_CODE, vid_stream)) {
    flush_bits32;

    if (vid_stream->picture.user_data != NULL) {
      free(vid_stream->picture.user_data);
      vid_stream->picture.user_data = NULL;
    }
    vid_stream->picture.user_data = get_ext_data(vid_stream);
  }
  /* Find a pict image structure in ring buffer not currently locked. */

  i = 0;

  while (vid_stream->ring[i]->locked != 0) {
    if (++i >= RING_BUF_SIZE) {
      perror("Fatal error. Ring buffer full.");
      exit(1);
    }
  }

  /* Set current pict image structure to the one just found in ring. */

  vid_stream->current = vid_stream->ring[i];

  /* Set time stamp. */

  vid_stream->current->show_time = time_stamp;

  /* Reset past macroblock address field. */

  vid_stream->mblock.past_mb_addr = -1;

  return PARSE_OK;
}



/*
 *--------------------------------------------------------------
 *
 * ParseSlice --
 *
 *      Parses off slice header.
 *
 * Results:
 *      Values found in slice header put into video stream structure.
 *
 * Side effects:
 *      Bit stream irreversibly parsed.
 *
 *--------------------------------------------------------------
 */

static int
ParseSlice(vid_stream)
  VidStream *vid_stream;
{
  unsigned int data;

  /* Flush slice start code. */

  flush_bits(24);

  /* Parse off slice vertical position. */

  get_bits8(data);
  vid_stream->slice.vert_pos = data;

  /* Parse off quantization scale. */

  get_bits5(data);
  vid_stream->slice.quant_scale = data;

  /* Parse off extra bit slice info. */

  if (vid_stream->slice.extra_info != NULL) {
    free(vid_stream->slice.extra_info);
    vid_stream->slice.extra_info = NULL;
  }
  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. */

  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;

  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