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_VPX_DSP_PROB_H_
12 #define VPX_VPX_DSP_PROB_H_
13
14 #include <assert.h>
15
16 #include "./vpx_config.h"
17 #include "./vpx_dsp_common.h"
18
19 #include "vpx_ports/mem.h"
20
21 #ifdef __cplusplus
22 extern "C" {
23 #endif
24
25 typedef uint8_t vpx_prob;
26
27 #define MAX_PROB 255
28
29 #define vpx_prob_half ((vpx_prob)128)
30
31 typedef int8_t vpx_tree_index;
32
33 #define TREE_SIZE(leaf_count) (2 * (leaf_count)-2)
34
35 #define vpx_complement(x) (255 - x)
36
37 #define MODE_MV_COUNT_SAT 20
38
39 /* We build coding trees compactly in arrays.
40 Each node of the tree is a pair of vpx_tree_indices.
41 Array index often references a corresponding probability table.
42 Index <= 0 means done encoding/decoding and value = -Index,
43 Index > 0 means need another bit, specification at index.
44 Nonnegative indices are always even; processing begins at node 0. */
45
46 typedef const vpx_tree_index vpx_tree[];
47
get_prob(unsigned int num,unsigned int den)48 static INLINE vpx_prob get_prob(unsigned int num, unsigned int den) {
49 assert(den != 0);
50 {
51 const int p = (int)(((uint64_t)num * 256 + (den >> 1)) / den);
52 // (p > 255) ? 255 : (p < 1) ? 1 : p;
53 const int clipped_prob = p | ((255 - p) >> 23) | (p == 0);
54 return (vpx_prob)clipped_prob;
55 }
56 }
57
get_binary_prob(unsigned int n0,unsigned int n1)58 static INLINE vpx_prob get_binary_prob(unsigned int n0, unsigned int n1) {
59 const unsigned int den = n0 + n1;
60 if (den == 0) return 128u;
61 return get_prob(n0, den);
62 }
63
64 /* This function assumes prob1 and prob2 are already within [1,255] range. */
weighted_prob(int prob1,int prob2,int factor)65 static INLINE vpx_prob weighted_prob(int prob1, int prob2, int factor) {
66 return ROUND_POWER_OF_TWO(prob1 * (256 - factor) + prob2 * factor, 8);
67 }
68
merge_probs(vpx_prob pre_prob,const unsigned int ct[2],unsigned int count_sat,unsigned int max_update_factor)69 static INLINE vpx_prob merge_probs(vpx_prob pre_prob, const unsigned int ct[2],
70 unsigned int count_sat,
71 unsigned int max_update_factor) {
72 const vpx_prob prob = get_binary_prob(ct[0], ct[1]);
73 const unsigned int count = VPXMIN(ct[0] + ct[1], count_sat);
74 const unsigned int factor = max_update_factor * count / count_sat;
75 return weighted_prob(pre_prob, prob, factor);
76 }
77
78 // MODE_MV_MAX_UPDATE_FACTOR (128) * count / MODE_MV_COUNT_SAT;
79 static const int count_to_update_factor[MODE_MV_COUNT_SAT + 1] = {
80 0, 6, 12, 19, 25, 32, 38, 44, 51, 57, 64,
81 70, 76, 83, 89, 96, 102, 108, 115, 121, 128
82 };
83
mode_mv_merge_probs(vpx_prob pre_prob,const unsigned int ct[2])84 static INLINE vpx_prob mode_mv_merge_probs(vpx_prob pre_prob,
85 const unsigned int ct[2]) {
86 const unsigned int den = ct[0] + ct[1];
87 if (den == 0) {
88 return pre_prob;
89 } else {
90 const unsigned int count = VPXMIN(den, MODE_MV_COUNT_SAT);
91 const unsigned int factor = count_to_update_factor[count];
92 const vpx_prob prob = get_prob(ct[0], den);
93 return weighted_prob(pre_prob, prob, factor);
94 }
95 }
96
97 void vpx_tree_merge_probs(const vpx_tree_index *tree, const vpx_prob *pre_probs,
98 const unsigned int *counts, vpx_prob *probs);
99
100 DECLARE_ALIGNED(16, extern const uint8_t, vpx_norm[256]);
101
102 #ifdef __cplusplus
103 } // extern "C"
104 #endif
105
106 #endif // VPX_VPX_DSP_PROB_H_
107