ebcot_encoder.h

JPEG2000实现的源码

         `passes' points to an array which is capable of holding `max_passes'
     entries, which describe the code size and rate-distortion slope at the
     end of each coding pass.  In practice, we do not allocate a separate
     array for each code block, but allocate a single array which holds the
     concatenated `passes' arrays from all code blocks in all tiles of the
     subband.  The first code block's `passes' field points to the head
     of this single allocated array.
         `insignificant_msbs' indicates the number of bit-planes, starting from
     the most significant magnitude bit of the IMPLEMENTATION_PRECISION-bit
     sign-magnitude words, for which all samples in the block were found to
     have zero magnitude.
         `byte_count_bits' is used by the T2 coding engine to code the
     number of bytes between successive termination and/or truncation points.
     Specifically, `byte_count_bits' holds the number of bytes per coding
     pass which were last used to signal differential code length information.
     To signal a new length quantity, L, corresponding to P new coding passes,
     we required the value of `byte_count_bits', B, to satisfy
     L < 2^(B*floor(log_2(P))).  A comma code is used to increment the
     value of B until this condition is satisfied, after which the value of
     L is signalled using B*floor(log_2(P)) bits.  The
     `old_byte_count_bits' field is used to save the value of `byte_count_bits'
     when conducting trials for rate control.  For more information,
     consult the "ebcot_send_bits.c" file.

     CRIL Technology/SAIC Scan Buffer begin
          The `next_unit' field is used by the return_units() function which
     is part of the dst_codeword_heap object.  This field effectively signals
     the last heap for the current block by specifying the next heap used
     at the beginning of any other block.
          The `next_unit_used' field signals the ending location within the
     last heap for current block by specifying the beginning location for any
     block which uses the `next_heap' heap.
     CRIL Technology/SAIC Scan Buffer end */

/*****************************************************************************/
/*                          ebcot_precinct_band_info                         */
/*****************************************************************************/

typedef
  struct ebcot_precinct_band_info {
    int blocks_high, blocks_wide, total_blocks, block_row_gap;
    ebcot_block_info_ptr blocks;
    struct ebcot_band_info *band;
    struct tag_tree_node *inclusion_tree;
    struct tag_tree_node *insignificant_msbs_tree;
    struct tag_tree_node *inclusion_tree_copy;
    struct tag_tree_node *insignificant_msbs_tree_copy;

    /* SAIC General Decomp. Begin */
    int valid_band;
    /* SAIC General Decomp. End */

  } ebcot_precinct_band_info, *ebcot_precinct_band_info_ptr;
  /* Holds information specific to a given precinct within a subband.
         `blocks_high' and `blocks_wide' hold the number of blocks required
     to span the height and width of the precinct within the relevant subband,
     while `total_blocks' holds the product of these two fields.  The
     `block_row_gap' field identifies the total number of code-blocks between
     consecutive rows of blocks within the `blocks' array.  In practice, this
     is identical to the `blocks_wide' field in the corresponding
     `ebcot_band_info' structure.
         `blocks' points to the first block of the precinct.  It is actually a
     pointer into the `blocks' array managed by the corresponding
     `ebcot_band_info' structure.  Each entry stores code words and summary
     information collected while coding the relevant block.  Note that this
     field may be NULL if the precinct contains no blocks; this can happen.
         `band' points to corresponding `ebcot_band_info' structure.
         `inclusion_tree' and `insignificant_msbs_tree' point to tag-tree
     structures which manage the efficient writing of tag bits to represent
     two types of information for the precinct.  The `inclusion_tree' structure
     is used to represent information about whether or not any coding passes
     have been included into the bit-stream so far, for each of the blocks in
     the precinct.  The `insignificant_msbs_tree' structure is used to represent
     information embodied in the `insignificant_msbs' field of each
     `ebcot_block_info' structure for blocks within the precinct.  Beyond this
     brief description, the use of these data structures is best understood
     by reading the comments appearing with the definition of tag trees in
     "ebcot_send_bits.h" and the implementation of the `form_packet' function
     in "ebcot_send_bits.c".
         `inclusion_tree_copy' and `insignificant_msbs_tree_copy' are provided
     to allow the state of a precinct construction phase to be saved and
     later recalled. .

      SAIC General Decomp. Begin
          `valid_band' indicates which bands in the range [min_band, max_band]
      are valid for a general decomposition.
      SAIC General Decomp. End */

/*****************************************************************************/
/*                             ebcot_precinct_info                           */
/*****************************************************************************/

typedef
  struct ebcot_precinct_info {
    int tnum, component_idx, level_idx, precinct_idx;
    int xref, yref;
    int min_band, max_band;
    ebcot_precinct_band_info_ptr bands;
    int included_layers;
    int *layer_bytes;
  } ebcot_precinct_info, *ebcot_precinct_info_ptr;
  /* Holds information specific to a given precinct.
         `tnum', `component_idx', `level_idx' and `precinct_idx'
     together specify the coordinates of the precinct within the entire
     code-stream.
         `xref' and `yref' hold the absolute coordinates of the upper left
     hand corner of the precinct, mapped into the high-resolution reference
     grid; these identify the location of the precinct in the same coordinate
     system as the containing `ebcot_tile' structure's `reference_dims'
     coordinates.  The information is used only when constructing spatially
     oriented precinct progression sequences.
         `min_band', `max_band' and `bands' play identical roles to
     their namesakes in the `ebcot_band_info' structure, except that
     the `bands' array contains `ebcot_precinct_band_info' structures
     which manage the state of each subband within the scope of the
     precincts.
         `included_layers' indicates the total number of quality layers
     which have been included so far while building the packet progression
     sequence managed by the `packet_sequence' array in the containing
     `ebcot_tile' structure.
         `layer_bytes' is an array with one entry for each quality layer
     available in the containing tile.  It is used to store the number of
     bytes occupied by each codestream packet (i.e. each quality layer within
     the scope of the current precinct). */

/* ========================================================================= */
/* ----------------------------- Line Buffering ---------------------------- */
/* ========================================================================= */

/*****************************************************************************/
/*                            ebcot_line_buffering                           */
/*****************************************************************************/

typedef
  struct ebcot_line_buffering {
    int num_lines;
    ebcot_block_info_ptr info;
    ifc_int **buffers;
  } ebcot_line_buffering, *ebcot_line_buffering_ptr;
  /* This structure manages buffering of subband lines within the current
     tile into a row of blocks, since data arrives from the quantizer in lines
     rather than blocks.
         `num_lines' holds the number of lines which have arrived.  Once
     this reaches the height of a block (or the end of the image or tile), the
     blocks will all be coded at once.
         `info' points to the `ebcot_block_info' entry for the first block in
     the row of blocks which is currently being accumulated.
         `buffers' points to a row of block buffers.  Each block buffer
     conforms to the requirements of the `sample_buffer' array described
     under the definition of the `block_master' structure. */


/* ========================================================================= */
/* ---------------------------- Subband Structure -------------------------- */
/* ========================================================================= */

/*****************************************************************************/
/*                               ebcot_band_info                             */
/*****************************************************************************/

typedef
  struct ebcot_band_info {
    int tnum, component_idx, level_idx, band_idx;
    int orientation_idx;
    canvas_dims dims;
    frame_info frame;
    int block_rows, block_cols;
    std_byte *zc_lut;
    dst_heap_unit_ptr heap_head, heap_tail;
    int next_heap_pos;
    float step_wmse;
    float vpw_weight;
    int extra_lsbs;
    int max_passes;
    float nominal_range;
    float fully_masked_sensitivity_reduction;
    int lossless;
    ebcot_line_buffering lines;
    block_coding_pass_func pass_funcs[PASSES_PER_BITPLANE];
    forward_roi_ref roi;
    int max_roi_boost;
    int roi_implicit;
    int blocks_wide, blocks_high, total_blocks;
    ebcot_block_info_ptr blocks;

    /* CRIL Technology/SAIC Scan Buffer begin */
    int scan_buffer_lines;
    int max_scan_buffer_lines;
    /* CRIL Technology/SAIC Scan Buffer end */

    /* SAIC/Fuji LRA begin */
    int quant_to_zero;
    /* SAIC/Fuji LRA end */

    /* SAIC General Decomp. Begin */
    int vert_hp_descent;
    int horiz_hp_descent;
    int vert_hp_descent_chg[4];
    int horiz_hp_descent_chg[4];
    int valid_band;
    /* SAIC General Decomp. End */

  } ebcot_band_info, *ebcot_band_info_ptr;
  /* This structure describes a single subband within the wavelet
     decomposition for a single tile.
         `tnum', `component_idx', `level_idx' and `band_idx' identify
     the complete coordinates of the subband.
         `orientation_idx' holds one of LL_BAND, HL_BAND, LH_BAND or HH_BAND,
     depending upon whether the subband's primary orientation corresponds to
     low-pass filtering in both directions, high-pass filtering in the
     horizontal direction, high-pass filtering in the vertical direction or
     high-pass filtering in both directions, respectively.  For Mallat
     decompositions, all subbands will have `band_idx' = `orientation_idx'.
     This is not true, however, for more complex decompositions in which
     the primary subbands in the relevant resolution level are decomposed
     further.  This is carefully explained in the master "ifc.h" header
     file.
         `dims' holds the location and dimensions of the subband within the
     relevant tile.
         `frame' holds framing information for the subband.
         `block_rows' and `block_cols' identify the dimensions of the
     actual code-block partition for the subband within the relevant tile.
     These are determined from the nominal code-block dimensions for the
     entire tile, the frame dimensions mapped into the subband (if they are
     to be respected) and the precinct partition dimensions mapped into the
     subband.