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
22 extern "C" {
23 #endif
24
25 typedef uint8_t vp9_prob;
26
27 #define MAX_PROB 255
28
29 #define vp9_prob_half ((vp9_prob) 128)
30
31 typedef 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
44 typedef const vp9_tree_index vp9_tree[];
45
clip_prob(int p)46 static INLINE vp9_prob clip_prob(int p) {
47 return (p > 255) ? 255 : (p < 1) ? 1 : p;
48 }
49
50 // int64 is not needed for normal frame level calculations.
51 // However when outputting entropy stats accumulated over many frames
52 // or even clips we can overflow int math.
53 #ifdef ENTROPY_STATS
get_prob(int num,int den)54 static INLINE vp9_prob get_prob(int num, int den) {
55 return (den == 0) ? 128u : clip_prob(((int64_t)num * 256 + (den >> 1)) / den);
56 }
57 #else
get_prob(int num,int den)58 static INLINE vp9_prob get_prob(int num, int den) {
59 return (den == 0) ? 128u : clip_prob((num * 256 + (den >> 1)) / den);
60 }
61 #endif
62
get_binary_prob(int n0,int n1)63 static INLINE vp9_prob get_binary_prob(int n0, int n1) {
64 return get_prob(n0, n0 + n1);
65 }
66
67 /* This function assumes prob1 and prob2 are already within [1,255] range. */
weighted_prob(int prob1,int prob2,int factor)68 static INLINE vp9_prob weighted_prob(int prob1, int prob2, int factor) {
69 return ROUND_POWER_OF_TWO(prob1 * (256 - factor) + prob2 * factor, 8);
70 }
71
merge_probs(vp9_prob pre_prob,const unsigned int ct[2],unsigned int count_sat,unsigned int max_update_factor)72 static INLINE vp9_prob merge_probs(vp9_prob pre_prob,
73 const unsigned int ct[2],
74 unsigned int count_sat,
75 unsigned int max_update_factor) {
76 const vp9_prob prob = get_binary_prob(ct[0], ct[1]);
77 const unsigned int count = MIN(ct[0] + ct[1], count_sat);
78 const unsigned int factor = max_update_factor * count / count_sat;
79 return weighted_prob(pre_prob, prob, factor);
80 }
81
82 void vp9_tree_merge_probs(const vp9_tree_index *tree, const vp9_prob *pre_probs,
83 const unsigned int *counts, unsigned int count_sat,
84 unsigned int max_update_factor, vp9_prob *probs);
85
86
87 DECLARE_ALIGNED(16, extern const uint8_t, vp9_norm[256]);
88
89 #ifdef __cplusplus
90 } // extern "C"
91 #endif
92
93 #endif // VP9_COMMON_VP9_PROB_H_
94