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comparison: media/libvpx/vp8/common/treecoder.h
media/libvpx/vp8/common/treecoder.h
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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_TREECODER_H | |
| 13 #define __INC_TREECODER_H | |
| 14 | |
| 15 typedef unsigned char vp8bc_index_t; /* probability index */ | |
| 16 | |
| 17 | |
| 18 typedef unsigned char vp8_prob; | |
| 19 | |
| 20 #define vp8_prob_half ( (vp8_prob) 128) | |
| 21 | |
| 22 typedef signed char vp8_tree_index; | |
| 23 struct bool_coder_spec; | |
| 24 | |
| 25 typedef struct bool_coder_spec bool_coder_spec; | |
| 26 typedef struct bool_writer bool_writer; | |
| 27 typedef struct bool_reader bool_reader; | |
| 28 | |
| 29 typedef const bool_coder_spec c_bool_coder_spec; | |
| 30 typedef const bool_writer c_bool_writer; | |
| 31 typedef const bool_reader c_bool_reader; | |
| 32 | |
| 33 | |
| 34 | |
| 35 # define vp8_complement( x) (255 - x) | |
| 36 | |
| 37 | |
| 38 /* We build coding trees compactly in arrays. | |
| 39 Each node of the tree is a pair of vp8_tree_indices. | |
| 40 Array index often references a corresponding probability table. | |
| 41 Index <= 0 means done encoding/decoding and value = -Index, | |
| 42 Index > 0 means need another bit, specification at index. | |
| 43 Nonnegative indices are always even; processing begins at node 0. */ | |
| 44 | |
| 45 typedef const vp8_tree_index vp8_tree[], *vp8_tree_p; | |
| 46 | |
| 47 | |
| 48 typedef const struct vp8_token_struct | |
| 49 { | |
| 50 int value; | |
| 51 int Len; | |
| 52 } vp8_token; | |
| 53 | |
| 54 /* Construct encoding array from tree. */ | |
| 55 | |
| 56 void vp8_tokens_from_tree(struct vp8_token_struct *, vp8_tree); | |
| 57 void vp8_tokens_from_tree_offset(struct vp8_token_struct *, vp8_tree, | |
| 58 int offset); | |
| 59 | |
| 60 | |
| 61 /* Convert array of token occurrence counts into a table of probabilities | |
| 62 for the associated binary encoding tree. Also writes count of branches | |
| 63 taken for each node on the tree; this facilitiates decisions as to | |
| 64 probability updates. */ | |
| 65 | |
| 66 void vp8_tree_probs_from_distribution( | |
| 67 int n, /* n = size of alphabet */ | |
| 68 vp8_token tok [ /* n */ ], | |
| 69 vp8_tree tree, | |
| 70 vp8_prob probs [ /* n-1 */ ], | |
| 71 unsigned int branch_ct [ /* n-1 */ ] [2], | |
| 72 const unsigned int num_events[ /* n */ ], | |
| 73 unsigned int Pfactor, | |
| 74 int Round | |
| 75 ); | |
| 76 | |
| 77 /* Variant of above using coder spec rather than hardwired 8-bit probs. */ | |
| 78 | |
| 79 void vp8bc_tree_probs_from_distribution( | |
| 80 int n, /* n = size of alphabet */ | |
| 81 vp8_token tok [ /* n */ ], | |
| 82 vp8_tree tree, | |
| 83 vp8_prob probs [ /* n-1 */ ], | |
| 84 unsigned int branch_ct [ /* n-1 */ ] [2], | |
| 85 const unsigned int num_events[ /* n */ ], | |
| 86 c_bool_coder_spec *s | |
| 87 ); | |
| 88 | |
| 89 | |
| 90 #endif |
