av1/common/entropy.h

/*
 * Copyright (c) 2016, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 2 Clause License and
 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
 * was not distributed with this source code in the LICENSE file, you can
 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 */

#ifndef AV1_COMMON_ENTROPY_H_
#define AV1_COMMON_ENTROPY_H_

#include "./aom_config.h"
#include "aom/aom_integer.h"
#if CONFIG_RANS
#include "aom_dsp/ans.h"
#endif  // CONFIG_RANS
#include "aom_dsp/prob.h"

#include "av1/common/common.h"
#include "av1/common/enums.h"

#ifdef __cplusplus
extern "C" {
#endif

#define DIFF_UPDATE_PROB 252
#define GROUP_DIFF_UPDATE_PROB 252

// 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 CATEGORY1_TOKEN 5   // 5-6   Extra Bits 1+1
#define CATEGORY2_TOKEN 6   // 7-10  Extra Bits 2+1
#define CATEGORY3_TOKEN 7   // 11-18 Extra Bits 3+1
#define CATEGORY4_TOKEN 8   // 19-34 Extra Bits 4+1
#define CATEGORY5_TOKEN 9   // 35-66 Extra Bits 5+1
#define CATEGORY6_TOKEN 10  // 67+   Extra Bits 14+1
#define EOB_TOKEN 11        // EOB   Extra Bits 0+0

#define ENTROPY_TOKENS 12

#define ENTROPY_NODES 11

DECLARE_ALIGNED(16, extern const uint8_t, av1_pt_energy_class[ENTROPY_TOKENS]);

#define CAT1_MIN_VAL 5
#define CAT2_MIN_VAL 7
#define CAT3_MIN_VAL 11
#define CAT4_MIN_VAL 19
#define CAT5_MIN_VAL 35
#define CAT6_MIN_VAL 67

// Extra bit probabilities.
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat1_prob[1]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat2_prob[2]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat3_prob[3]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat4_prob[4]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat5_prob[5]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat6_prob[14]);

#if CONFIG_AOM_HIGHBITDEPTH
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat1_prob_high10[1]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat2_prob_high10[2]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat3_prob_high10[3]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat4_prob_high10[4]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat5_prob_high10[5]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat6_prob_high10[16]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat1_prob_high12[1]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat2_prob_high12[2]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat3_prob_high12[3]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat4_prob_high12[4]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat5_prob_high12[5]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_cat6_prob_high12[18]);
#endif  // CONFIG_AOM_HIGHBITDEPTH

#define EOB_MODEL_TOKEN 3

typedef struct {
  const aom_tree_index *tree;
  const aom_prob *prob;
  int len;
  int base_val;
  const int16_t *cost;
} av1_extra_bit;

// indexed by token value
extern const av1_extra_bit av1_extra_bits[ENTROPY_TOKENS];
#if CONFIG_AOM_HIGHBITDEPTH
extern const av1_extra_bit av1_extra_bits_high10[ENTROPY_TOKENS];
extern const av1_extra_bit av1_extra_bits_high12[ENTROPY_TOKENS];
#endif  // CONFIG_AOM_HIGHBITDEPTH

#define DCT_MAX_VALUE 16384
#if CONFIG_AOM_HIGHBITDEPTH
#define DCT_MAX_VALUE_HIGH10 65536
#define DCT_MAX_VALUE_HIGH12 262144
#endif  // CONFIG_AOM_HIGHBITDEPTH

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

#define REF_TYPES 2  // intra=0, inter=1

/* Middle dimension reflects the coefficient position within the transform. */
#define COEF_BANDS 6

/* Inside dimension is measure of nearby complexity, that reflects the energy
   of 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 determined by the size of the
   most recently decoded coefficient.
   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 COEFF_CONTEXTS 6
#define BAND_COEFF_CONTEXTS(band) ((band) == 0 ? 3 : COEFF_CONTEXTS)

// #define ENTROPY_STATS

typedef unsigned int
    av1_coeff_count[REF_TYPES][COEF_BANDS][COEFF_CONTEXTS][ENTROPY_TOKENS];
typedef unsigned int
    av1_coeff_stats[REF_TYPES][COEF_BANDS][COEFF_CONTEXTS][ENTROPY_NODES][2];

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

struct AV1Common;
void av1_default_coef_probs(struct AV1Common *cm);
void av1_adapt_coef_probs(struct AV1Common *cm);

// This is the index in the scan order beyond which all coefficients for
// 8x8 transform and above are in the top band.
// This macro is currently unused but may be used by certain implementations
#define MAXBAND_INDEX 21

DECLARE_ALIGNED(16, extern const uint8_t, av1_coefband_trans_8x8plus[1024]);
DECLARE_ALIGNED(16, extern const uint8_t, av1_coefband_trans_4x4[16]);

static INLINE const uint8_t *get_band_translate(TX_SIZE tx_size) {
  return tx_size == TX_4X4 ? av1_coefband_trans_4x4
                           : av1_coefband_trans_8x8plus;
}

// 128 lists of probabilities are stored for the following ONE node probs:
// 1, 3, 5, 7, ..., 253, 255
// In between probabilities are interpolated linearly

#define COEFF_PROB_MODELS 255

#define UNCONSTRAINED_NODES 3

#define PIVOT_NODE 2  // which node is pivot

#define MODEL_NODES (ENTROPY_NODES - UNCONSTRAINED_NODES)
extern const aom_tree_index av1_coef_con_tree[TREE_SIZE(ENTROPY_TOKENS)];
extern const aom_prob av1_pareto8_full[COEFF_PROB_MODELS][MODEL_NODES];

typedef aom_prob av1_coeff_probs_model[REF_TYPES][COEF_BANDS][COEFF_CONTEXTS]
                                      [UNCONSTRAINED_NODES];

typedef unsigned int av1_coeff_count_model
    [REF_TYPES][COEF_BANDS][COEFF_CONTEXTS][UNCONSTRAINED_NODES + 1];

void av1_model_to_full_probs(const aom_prob *model, aom_prob *full);

#if CONFIG_RANS
typedef rans_lut coeff_cdf_model[REF_TYPES][COEF_BANDS][COEFF_CONTEXTS];
extern const AnsP10
    av1_pareto8_token_probs[COEFF_PROB_MODELS][ENTROPY_TOKENS - 2];
struct frame_contexts;
void av1_coef_pareto_cdfs(struct frame_contexts *fc);
#endif  // CONFIG_RANS

typedef char ENTROPY_CONTEXT;

static INLINE int combine_entropy_contexts(ENTROPY_CONTEXT a,
                                           ENTROPY_CONTEXT b) {
  return (a != 0) + (b != 0);
}

static INLINE int get_entropy_context(TX_SIZE tx_size, const ENTROPY_CONTEXT *a,
                                      const ENTROPY_CONTEXT *l) {
  ENTROPY_CONTEXT above_ec = 0, left_ec = 0;

  switch (tx_size) {
    case TX_4X4:
      above_ec = a[0] != 0;
      left_ec = l[0] != 0;
      break;
    case TX_8X8:
      above_ec = !!*(const uint16_t *)a;
      left_ec = !!*(const uint16_t *)l;
      break;
    case TX_16X16:
      above_ec = !!*(const uint32_t *)a;
      left_ec = !!*(const uint32_t *)l;
      break;
    case TX_32X32:
      above_ec = !!*(const uint64_t *)a;
      left_ec = !!*(const uint64_t *)l;
      break;
    default: assert(0 && "Invalid transform size."); break;
  }

  return combine_entropy_contexts(above_ec, left_ec);
}

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // AV1_COMMON_ENTROPY_H_