media/libvpx/vp8/common/treecoder.c@6474c204b198 (annotated)
media/libvpx/vp8/common/treecoder.c
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /* |
| michael@0 | 2 | * Copyright (c) 2010 The WebM project authors. All Rights Reserved. |
| michael@0 | 3 | * |
| michael@0 | 4 | * Use of this source code is governed by a BSD-style license |
| michael@0 | 5 | * that can be found in the LICENSE file in the root of the source |
| michael@0 | 6 | * tree. An additional intellectual property rights grant can be found |
| michael@0 | 7 | * in the file PATENTS. All contributing project authors may |
| michael@0 | 8 | * be found in the AUTHORS file in the root of the source tree. |
| michael@0 | 9 | */ |
| michael@0 | 10 | |
| michael@0 | 11 | |
| michael@0 | 12 | #if CONFIG_DEBUG |
| michael@0 | 13 | #include <assert.h> |
| michael@0 | 14 | #endif |
| michael@0 | 15 | #include <stdio.h> |
| michael@0 | 16 | |
| michael@0 | 17 | #include "treecoder.h" |
| michael@0 | 18 | |
| michael@0 | 19 | static void tree2tok( |
| michael@0 | 20 | struct vp8_token_struct *const p, |
| michael@0 | 21 | vp8_tree t, |
| michael@0 | 22 | int i, |
| michael@0 | 23 | int v, |
| michael@0 | 24 | int L |
| michael@0 | 25 | ) |
| michael@0 | 26 | { |
| michael@0 | 27 | v += v; |
| michael@0 | 28 | ++L; |
| michael@0 | 29 | |
| michael@0 | 30 | do |
| michael@0 | 31 | { |
| michael@0 | 32 | const vp8_tree_index j = t[i++]; |
| michael@0 | 33 | |
| michael@0 | 34 | if (j <= 0) |
| michael@0 | 35 | { |
| michael@0 | 36 | p[-j].value = v; |
| michael@0 | 37 | p[-j].Len = L; |
| michael@0 | 38 | } |
| michael@0 | 39 | else |
| michael@0 | 40 | tree2tok(p, t, j, v, L); |
| michael@0 | 41 | } |
| michael@0 | 42 | while (++v & 1); |
| michael@0 | 43 | } |
| michael@0 | 44 | |
| michael@0 | 45 | void vp8_tokens_from_tree(struct vp8_token_struct *p, vp8_tree t) |
| michael@0 | 46 | { |
| michael@0 | 47 | tree2tok(p, t, 0, 0, 0); |
| michael@0 | 48 | } |
| michael@0 | 49 | |
| michael@0 | 50 | void vp8_tokens_from_tree_offset(struct vp8_token_struct *p, vp8_tree t, |
| michael@0 | 51 | int offset) |
| michael@0 | 52 | { |
| michael@0 | 53 | tree2tok(p - offset, t, 0, 0, 0); |
| michael@0 | 54 | } |
| michael@0 | 55 | |
| michael@0 | 56 | static void branch_counts( |
| michael@0 | 57 | int n, /* n = size of alphabet */ |
| michael@0 | 58 | vp8_token tok [ /* n */ ], |
| michael@0 | 59 | vp8_tree tree, |
| michael@0 | 60 | unsigned int branch_ct [ /* n-1 */ ] [2], |
| michael@0 | 61 | const unsigned int num_events[ /* n */ ] |
| michael@0 | 62 | ) |
| michael@0 | 63 | { |
| michael@0 | 64 | const int tree_len = n - 1; |
| michael@0 | 65 | int t = 0; |
| michael@0 | 66 | |
| michael@0 | 67 | #if CONFIG_DEBUG |
| michael@0 | 68 | assert(tree_len); |
| michael@0 | 69 | #endif |
| michael@0 | 70 | |
| michael@0 | 71 | do |
| michael@0 | 72 | { |
| michael@0 | 73 | branch_ct[t][0] = branch_ct[t][1] = 0; |
| michael@0 | 74 | } |
| michael@0 | 75 | while (++t < tree_len); |
| michael@0 | 76 | |
| michael@0 | 77 | t = 0; |
| michael@0 | 78 | |
| michael@0 | 79 | do |
| michael@0 | 80 | { |
| michael@0 | 81 | int L = tok[t].Len; |
| michael@0 | 82 | const int enc = tok[t].value; |
| michael@0 | 83 | const unsigned int ct = num_events[t]; |
| michael@0 | 84 | |
| michael@0 | 85 | vp8_tree_index i = 0; |
| michael@0 | 86 | |
| michael@0 | 87 | do |
| michael@0 | 88 | { |
| michael@0 | 89 | const int b = (enc >> --L) & 1; |
| michael@0 | 90 | const int j = i >> 1; |
| michael@0 | 91 | #if CONFIG_DEBUG |
| michael@0 | 92 | assert(j < tree_len && 0 <= L); |
| michael@0 | 93 | #endif |
| michael@0 | 94 | |
| michael@0 | 95 | branch_ct [j] [b] += ct; |
| michael@0 | 96 | i = tree[ i + b]; |
| michael@0 | 97 | } |
| michael@0 | 98 | while (i > 0); |
| michael@0 | 99 | |
| michael@0 | 100 | #if CONFIG_DEBUG |
| michael@0 | 101 | assert(!L); |
| michael@0 | 102 | #endif |
| michael@0 | 103 | } |
| michael@0 | 104 | while (++t < n); |
| michael@0 | 105 | |
| michael@0 | 106 | } |
| michael@0 | 107 | |
| michael@0 | 108 | |
| michael@0 | 109 | void vp8_tree_probs_from_distribution( |
| michael@0 | 110 | int n, /* n = size of alphabet */ |
| michael@0 | 111 | vp8_token tok [ /* n */ ], |
| michael@0 | 112 | vp8_tree tree, |
| michael@0 | 113 | vp8_prob probs [ /* n-1 */ ], |
| michael@0 | 114 | unsigned int branch_ct [ /* n-1 */ ] [2], |
| michael@0 | 115 | const unsigned int num_events[ /* n */ ], |
| michael@0 | 116 | unsigned int Pfac, |
| michael@0 | 117 | int rd |
| michael@0 | 118 | ) |
| michael@0 | 119 | { |
| michael@0 | 120 | const int tree_len = n - 1; |
| michael@0 | 121 | int t = 0; |
| michael@0 | 122 | |
| michael@0 | 123 | branch_counts(n, tok, tree, branch_ct, num_events); |
| michael@0 | 124 | |
| michael@0 | 125 | do |
| michael@0 | 126 | { |
| michael@0 | 127 | const unsigned int *const c = branch_ct[t]; |
| michael@0 | 128 | const unsigned int tot = c[0] + c[1]; |
| michael@0 | 129 | |
| michael@0 | 130 | #if CONFIG_DEBUG |
| michael@0 | 131 | assert(tot < (1 << 24)); /* no overflow below */ |
| michael@0 | 132 | #endif |
| michael@0 | 133 | |
| michael@0 | 134 | if (tot) |
| michael@0 | 135 | { |
| michael@0 | 136 | const unsigned int p = ((c[0] * Pfac) + (rd ? tot >> 1 : 0)) / tot; |
| michael@0 | 137 | probs[t] = p < 256 ? (p ? p : 1) : 255; /* agree w/old version for now */ |
| michael@0 | 138 | } |
| michael@0 | 139 | else |
| michael@0 | 140 | probs[t] = vp8_prob_half; |
| michael@0 | 141 | } |
| michael@0 | 142 | while (++t < tree_len); |
| michael@0 | 143 | } |
