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 VP9_COMMON_VP9_PROB_H_
12#define VP9_COMMON_VP9_PROB_H_
13
14#include "./vpx_config.h"
15
16#include "vpx_ports/mem.h"
17#include "vpx/vpx_integer.h"
18
19#include "vp9/common/vp9_common.h"
20
21#ifdef __cplusplus
22extern "C" {
23#endif
24
25typedef uint8_t vp9_prob;
26
27#define MAX_PROB 255
28
29#define vp9_prob_half ((vp9_prob) 128)
30
31typedef int8_t vp9_tree_index;
32
33#define TREE_SIZE(leaf_count) (2 * (leaf_count) - 2)
34
35#define vp9_complement(x) (255 - x)
36
37/* We build coding trees compactly in arrays.
38   Each node of the tree is a pair of vp9_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 vp9_tree_index vp9_tree[];
45
46static INLINE vp9_prob clip_prob(int p) {
47  return (p > 255) ? 255 : (p < 1) ? 1 : p;
48}
49
50static INLINE vp9_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 vp9_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 vp9_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 vp9_prob merge_probs(vp9_prob pre_prob,
64                                   const unsigned int ct[2],
65                                   unsigned int count_sat,
66                                   unsigned int max_update_factor) {
67  const vp9_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
73void vp9_tree_merge_probs(const vp9_tree_index *tree, const vp9_prob *pre_probs,
74                          const unsigned int *counts, unsigned int count_sat,
75                          unsigned int max_update_factor, vp9_prob *probs);
76
77
78DECLARE_ALIGNED(16, extern const uint8_t, vp9_norm[256]);
79
80#ifdef __cplusplus
81}  // extern "C"
82#endif
83
84#endif  // VP9_COMMON_VP9_PROB_H_
85