vp8/common/entropy.h

/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */


#ifndef __INC_ENTROPY_H
#define __INC_ENTROPY_H

#include "treecoder.h"
#include "blockd.h"
#include "common.h"
#include "coefupdateprobs.h"

extern const int vp9_i8x8_block[4];

/* Coefficient token alphabet */

#define ZERO_TOKEN              0       /* 0         Extra Bits 0+0 */
#define ONE_TOKEN               1       /* 1         Extra Bits 0+1 */
#define TWO_TOKEN               2       /* 2         Extra Bits 0+1 */
#define THREE_TOKEN             3       /* 3         Extra Bits 0+1 */
#define FOUR_TOKEN              4       /* 4         Extra Bits 0+1 */
#define DCT_VAL_CATEGORY1       5       /* 5-6       Extra Bits 1+1 */
#define DCT_VAL_CATEGORY2       6       /* 7-10      Extra Bits 2+1 */
#define DCT_VAL_CATEGORY3       7       /* 11-18     Extra Bits 3+1 */
#define DCT_VAL_CATEGORY4       8       /* 19-34     Extra Bits 4+1 */
#define DCT_VAL_CATEGORY5       9       /* 35-66     Extra Bits 5+1 */
#define DCT_VAL_CATEGORY6       10      /* 67+       Extra Bits 13+1 */
#define DCT_EOB_TOKEN           11      /* EOB       Extra Bits 0+0 */
#define MAX_ENTROPY_TOKENS 12
#define ENTROPY_NODES 11
#define EOSB_TOKEN              127     /* Not signalled, encoder only */

extern const vp9_tree_index vp9_coef_tree[];

extern struct vp9_token_struct vp9_coef_encodings[MAX_ENTROPY_TOKENS];

typedef struct {
  vp9_tree_p tree;
  const vp9_prob *prob;
  int Len;
  int base_val;
} vp9_extra_bit_struct;

extern vp9_extra_bit_struct vp9_extra_bits[12];    /* indexed by token value */

#define PROB_UPDATE_BASELINE_COST   7

#define MAX_PROB                255
#define DCT_MAX_VALUE           8192

/* Coefficients are predicted via a 3-dimensional probability table. */

/* Outside dimension.  0 = Y no DC, 1 = Y2, 2 = UV, 3 = Y with DC */
#define BLOCK_TYPES 4

#define BLOCK_TYPES_8X8 4

#define BLOCK_TYPES_16X16 4

/* Middle dimension is a coarsening of the coefficient's
   position within the 4x4 DCT. */

#define COEF_BANDS 8
extern DECLARE_ALIGNED(16, const int, vp9_coef_bands[16]);
extern DECLARE_ALIGNED(64, const int, vp9_coef_bands_8x8[64]);
extern DECLARE_ALIGNED(16, const int, vp9_coef_bands_16x16[256]);

/* Inside dimension is 3-valued measure of nearby complexity, that is,
   the extent to which nearby coefficients are nonzero.  For the first
   coefficient (DC, unless block type is 0), we look at the (already encoded)
   blocks above and to the left of the current block.  The context index is
   then the number (0,1,or 2) of these blocks having nonzero coefficients.
   After decoding a coefficient, the measure is roughly the size of the
   most recently decoded coefficient (0 for 0, 1 for 1, 2 for >1).
   Note that the intuitive meaning of this measure changes as coefficients
   are decoded, e.g., prior to the first token, a zero means that my neighbors
   are empty while, after the first token, because of the use of end-of-block,
   a zero means we just decoded a zero and hence guarantees that a non-zero
   coefficient will appear later in this block.  However, this shift
   in meaning is perfectly OK because our context depends also on the
   coefficient band (and since zigzag positions 0, 1, and 2 are in
   distinct bands). */

/*# define DC_TOKEN_CONTEXTS        3*/ /* 00, 0!0, !0!0 */
#define PREV_COEF_CONTEXTS       4

#define SUBEXP_PARAM                4   /* Subexponential code parameter */
#define MODULUS_PARAM               13  /* Modulus parameter */

extern DECLARE_ALIGNED(16, const unsigned char, vp9_prev_token_class[MAX_ENTROPY_TOKENS]);

struct VP9Common;
void vp9_default_coef_probs(struct VP9Common *);
extern DECLARE_ALIGNED(16, const int, vp9_default_zig_zag1d[16]);

extern DECLARE_ALIGNED(16, const int, vp9_col_scan[16]);
extern DECLARE_ALIGNED(16, const int, vp9_row_scan[16]);

extern DECLARE_ALIGNED(64, const int, vp9_default_zig_zag1d_8x8[64]);
void vp9_coef_tree_initialize(void);

extern DECLARE_ALIGNED(16, const int, vp9_default_zig_zag1d_16x16[256]);
void vp9_adapt_coef_probs(struct VP9Common *);

#endif