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comparison: media/libvpx/vp8/common/treecoder.c
media/libvpx/vp8/common/treecoder.c
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| -1:000000000000 | 0:a4163a16ab84 |
|---|---|
| 1 /* | |
| 2 * Copyright (c) 2010 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 | |
| 12 #if CONFIG_DEBUG | |
| 13 #include <assert.h> | |
| 14 #endif | |
| 15 #include <stdio.h> | |
| 16 | |
| 17 #include "treecoder.h" | |
| 18 | |
| 19 static void tree2tok( | |
| 20 struct vp8_token_struct *const p, | |
| 21 vp8_tree t, | |
| 22 int i, | |
| 23 int v, | |
| 24 int L | |
| 25 ) | |
| 26 { | |
| 27 v += v; | |
| 28 ++L; | |
| 29 | |
| 30 do | |
| 31 { | |
| 32 const vp8_tree_index j = t[i++]; | |
| 33 | |
| 34 if (j <= 0) | |
| 35 { | |
| 36 p[-j].value = v; | |
| 37 p[-j].Len = L; | |
| 38 } | |
| 39 else | |
| 40 tree2tok(p, t, j, v, L); | |
| 41 } | |
| 42 while (++v & 1); | |
| 43 } | |
| 44 | |
| 45 void vp8_tokens_from_tree(struct vp8_token_struct *p, vp8_tree t) | |
| 46 { | |
| 47 tree2tok(p, t, 0, 0, 0); | |
| 48 } | |
| 49 | |
| 50 void vp8_tokens_from_tree_offset(struct vp8_token_struct *p, vp8_tree t, | |
| 51 int offset) | |
| 52 { | |
| 53 tree2tok(p - offset, t, 0, 0, 0); | |
| 54 } | |
| 55 | |
| 56 static void branch_counts( | |
| 57 int n, /* n = size of alphabet */ | |
| 58 vp8_token tok [ /* n */ ], | |
| 59 vp8_tree tree, | |
| 60 unsigned int branch_ct [ /* n-1 */ ] [2], | |
| 61 const unsigned int num_events[ /* n */ ] | |
| 62 ) | |
| 63 { | |
| 64 const int tree_len = n - 1; | |
| 65 int t = 0; | |
| 66 | |
| 67 #if CONFIG_DEBUG | |
| 68 assert(tree_len); | |
| 69 #endif | |
| 70 | |
| 71 do | |
| 72 { | |
| 73 branch_ct[t][0] = branch_ct[t][1] = 0; | |
| 74 } | |
| 75 while (++t < tree_len); | |
| 76 | |
| 77 t = 0; | |
| 78 | |
| 79 do | |
| 80 { | |
| 81 int L = tok[t].Len; | |
| 82 const int enc = tok[t].value; | |
| 83 const unsigned int ct = num_events[t]; | |
| 84 | |
| 85 vp8_tree_index i = 0; | |
| 86 | |
| 87 do | |
| 88 { | |
| 89 const int b = (enc >> --L) & 1; | |
| 90 const int j = i >> 1; | |
| 91 #if CONFIG_DEBUG | |
| 92 assert(j < tree_len && 0 <= L); | |
| 93 #endif | |
| 94 | |
| 95 branch_ct [j] [b] += ct; | |
| 96 i = tree[ i + b]; | |
| 97 } | |
| 98 while (i > 0); | |
| 99 | |
| 100 #if CONFIG_DEBUG | |
| 101 assert(!L); | |
| 102 #endif | |
| 103 } | |
| 104 while (++t < n); | |
| 105 | |
| 106 } | |
| 107 | |
| 108 | |
| 109 void vp8_tree_probs_from_distribution( | |
| 110 int n, /* n = size of alphabet */ | |
| 111 vp8_token tok [ /* n */ ], | |
| 112 vp8_tree tree, | |
| 113 vp8_prob probs [ /* n-1 */ ], | |
| 114 unsigned int branch_ct [ /* n-1 */ ] [2], | |
| 115 const unsigned int num_events[ /* n */ ], | |
| 116 unsigned int Pfac, | |
| 117 int rd | |
| 118 ) | |
| 119 { | |
| 120 const int tree_len = n - 1; | |
| 121 int t = 0; | |
| 122 | |
| 123 branch_counts(n, tok, tree, branch_ct, num_events); | |
| 124 | |
| 125 do | |
| 126 { | |
| 127 const unsigned int *const c = branch_ct[t]; | |
| 128 const unsigned int tot = c[0] + c[1]; | |
| 129 | |
| 130 #if CONFIG_DEBUG | |
| 131 assert(tot < (1 << 24)); /* no overflow below */ | |
| 132 #endif | |
| 133 | |
| 134 if (tot) | |
| 135 { | |
| 136 const unsigned int p = ((c[0] * Pfac) + (rd ? tot >> 1 : 0)) / tot; | |
| 137 probs[t] = p < 256 ? (p ? p : 1) : 255; /* agree w/old version for now */ | |
| 138 } | |
| 139 else | |
| 140 probs[t] = vp8_prob_half; | |
| 141 } | |
| 142 while (++t < tree_len); | |
| 143 } |
