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comparison: media/libvpx/vp8/encoder/treewriter.h
media/libvpx/vp8/encoder/treewriter.h
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| -1:000000000000 | 0:13f04246b869 |
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| 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 #ifndef __INC_TREEWRITER_H | |
| 13 #define __INC_TREEWRITER_H | |
| 14 | |
| 15 /* Trees map alphabets into huffman-like codes suitable for an arithmetic | |
| 16 bit coder. Timothy S Murphy 11 October 2004 */ | |
| 17 | |
| 18 #include "vp8/common/treecoder.h" | |
| 19 | |
| 20 #include "boolhuff.h" /* for now */ | |
| 21 | |
| 22 typedef BOOL_CODER vp8_writer; | |
| 23 | |
| 24 #define vp8_write vp8_encode_bool | |
| 25 #define vp8_write_literal vp8_encode_value | |
| 26 #define vp8_write_bit( W, V) vp8_write( W, V, vp8_prob_half) | |
| 27 | |
| 28 #define vp8bc_write vp8bc_write_bool | |
| 29 #define vp8bc_write_literal vp8bc_write_bits | |
| 30 #define vp8bc_write_bit( W, V) vp8bc_write_bits( W, V, 1) | |
| 31 | |
| 32 | |
| 33 /* Approximate length of an encoded bool in 256ths of a bit at given prob */ | |
| 34 | |
| 35 #define vp8_cost_zero( x) ( vp8_prob_cost[x]) | |
| 36 #define vp8_cost_one( x) vp8_cost_zero( vp8_complement(x)) | |
| 37 | |
| 38 #define vp8_cost_bit( x, b) vp8_cost_zero( (b)? vp8_complement(x) : (x) ) | |
| 39 | |
| 40 /* VP8BC version is scaled by 2^20 rather than 2^8; see bool_coder.h */ | |
| 41 | |
| 42 | |
| 43 /* Both of these return bits, not scaled bits. */ | |
| 44 | |
| 45 static unsigned int vp8_cost_branch(const unsigned int ct[2], vp8_prob p) | |
| 46 { | |
| 47 /* Imitate existing calculation */ | |
| 48 | |
| 49 return ((ct[0] * vp8_cost_zero(p)) | |
| 50 + (ct[1] * vp8_cost_one(p))) >> 8; | |
| 51 } | |
| 52 | |
| 53 /* Small functions to write explicit values and tokens, as well as | |
| 54 estimate their lengths. */ | |
| 55 | |
| 56 static void vp8_treed_write | |
| 57 ( | |
| 58 vp8_writer *const w, | |
| 59 vp8_tree t, | |
| 60 const vp8_prob *const p, | |
| 61 int v, | |
| 62 int n /* number of bits in v, assumed nonzero */ | |
| 63 ) | |
| 64 { | |
| 65 vp8_tree_index i = 0; | |
| 66 | |
| 67 do | |
| 68 { | |
| 69 const int b = (v >> --n) & 1; | |
| 70 vp8_write(w, b, p[i>>1]); | |
| 71 i = t[i+b]; | |
| 72 } | |
| 73 while (n); | |
| 74 } | |
| 75 static void vp8_write_token | |
| 76 ( | |
| 77 vp8_writer *const w, | |
| 78 vp8_tree t, | |
| 79 const vp8_prob *const p, | |
| 80 vp8_token *const x | |
| 81 ) | |
| 82 { | |
| 83 vp8_treed_write(w, t, p, x->value, x->Len); | |
| 84 } | |
| 85 | |
| 86 static int vp8_treed_cost( | |
| 87 vp8_tree t, | |
| 88 const vp8_prob *const p, | |
| 89 int v, | |
| 90 int n /* number of bits in v, assumed nonzero */ | |
| 91 ) | |
| 92 { | |
| 93 int c = 0; | |
| 94 vp8_tree_index i = 0; | |
| 95 | |
| 96 do | |
| 97 { | |
| 98 const int b = (v >> --n) & 1; | |
| 99 c += vp8_cost_bit(p[i>>1], b); | |
| 100 i = t[i+b]; | |
| 101 } | |
| 102 while (n); | |
| 103 | |
| 104 return c; | |
| 105 } | |
| 106 static int vp8_cost_token | |
| 107 ( | |
| 108 vp8_tree t, | |
| 109 const vp8_prob *const p, | |
| 110 vp8_token *const x | |
| 111 ) | |
| 112 { | |
| 113 return vp8_treed_cost(t, p, x->value, x->Len); | |
| 114 } | |
| 115 | |
| 116 /* Fill array of costs for all possible token values. */ | |
| 117 | |
| 118 void vp8_cost_tokens( | |
| 119 int *Costs, const vp8_prob *, vp8_tree | |
| 120 ); | |
| 121 | |
| 122 void vp8_cost_tokens2( | |
| 123 int *Costs, const vp8_prob *, vp8_tree, int | |
| 124 ); | |
| 125 | |
| 126 #endif |
