1/*
2 *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#ifndef VPX_DSP_PROB_H_
12#define VPX_DSP_PROB_H_
13
14#include "./vpx_config.h"
15#include "./vpx_dsp_common.h"
16
17#include "vpx_ports/mem.h"
18
19#ifdef __cplusplus
20extern "C" {
21#endif
22
23typedef uint8_t vpx_prob;
24
25#define MAX_PROB 255
26
27#define vpx_prob_half ((vpx_prob) 128)
28
29typedef int8_t vpx_tree_index;
30
31#define TREE_SIZE(leaf_count) (2 * (leaf_count) - 2)
32
33#define vpx_complement(x) (255 - x)
34
35#define MODE_MV_COUNT_SAT 20
36
37/* We build coding trees compactly in arrays.
38   Each node of the tree is a pair of vpx_tree_indices.
39   Array index often references a corresponding probability table.
40   Index <= 0 means done encoding/decoding and value = -Index,
41   Index > 0 means need another bit, specification at index.
42   Nonnegative indices are always even;  processing begins at node 0. */
43
44typedef const vpx_tree_index vpx_tree[];
45
46static INLINE vpx_prob clip_prob(int p) {
47  return (p > 255) ? 255 : (p < 1) ? 1 : p;
48}
49
50static INLINE vpx_prob get_prob(int num, int den) {
51  return (den == 0) ? 128u : clip_prob(((int64_t)num * 256 + (den >> 1)) / den);
52}
53
54static INLINE vpx_prob get_binary_prob(int n0, int n1) {
55  return get_prob(n0, n0 + n1);
56}
57
58/* This function assumes prob1 and prob2 are already within [1,255] range. */
59static INLINE vpx_prob weighted_prob(int prob1, int prob2, int factor) {
60  return ROUND_POWER_OF_TWO(prob1 * (256 - factor) + prob2 * factor, 8);
61}
62
63static INLINE vpx_prob merge_probs(vpx_prob pre_prob,
64                                   const unsigned int ct[2],
65                                   unsigned int count_sat,
66                                   unsigned int max_update_factor) {
67  const vpx_prob prob = get_binary_prob(ct[0], ct[1]);
68  const unsigned int count = MIN(ct[0] + ct[1], count_sat);
69  const unsigned int factor = max_update_factor * count / count_sat;
70  return weighted_prob(pre_prob, prob, factor);
71}
72
73// MODE_MV_MAX_UPDATE_FACTOR (128) * count / MODE_MV_COUNT_SAT;
74static const int count_to_update_factor[MODE_MV_COUNT_SAT + 1] = {
75  0, 6, 12, 19, 25, 32, 38, 44, 51, 57, 64,
76  70, 76, 83, 89, 96, 102, 108, 115, 121, 128
77};
78
79static INLINE vpx_prob mode_mv_merge_probs(vpx_prob pre_prob,
80                                           const unsigned int ct[2]) {
81  const unsigned int den = ct[0] + ct[1];
82  if (den == 0) {
83    return pre_prob;
84  } else {
85    const unsigned int count = MIN(den, MODE_MV_COUNT_SAT);
86    const unsigned int factor = count_to_update_factor[count];
87    const vpx_prob prob =
88        clip_prob(((int64_t)(ct[0]) * 256 + (den >> 1)) / den);
89    return weighted_prob(pre_prob, prob, factor);
90  }
91}
92
93void vpx_tree_merge_probs(const vpx_tree_index *tree, const vpx_prob *pre_probs,
94                          const unsigned int *counts, vpx_prob *probs);
95
96
97DECLARE_ALIGNED(16, extern const uint8_t, vpx_norm[256]);
98
99#ifdef __cplusplus
100}  // extern "C"
101#endif
102
103#endif  // VPX_DSP_PROB_H_
104