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 20 extern "C" { 21 #endif 22 23 typedef uint8_t vpx_prob; 24 25 #define MAX_PROB 255 26 27 #define vpx_prob_half ((vpx_prob) 128) 28 29 typedef 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 44 typedef const vpx_tree_index vpx_tree[]; 45 46 static INLINE vpx_prob clip_prob(int p) { 47 return (p > 255) ? 255 : (p < 1) ? 1 : p; 48 } 49 50 static 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 54 static 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. */ 59 static 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 63 static 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 = VPXMIN(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; 74 static 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 79 static 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 = VPXMIN(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 93 void vpx_tree_merge_probs(const vpx_tree_index *tree, const vpx_prob *pre_probs, 94 const unsigned int *counts, vpx_prob *probs); 95 96 97 DECLARE_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
