84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
/*
|
|
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license
|
|
* that can be found in the LICENSE file in the root of the source
|
|
* tree. An additional intellectual property rights grant can be found
|
|
* in the file PATENTS. All contributing project authors may
|
|
* be found in the AUTHORS file in the root of the source tree.
|
|
*/
|
|
|
|
|
|
#ifndef VP9_COMMON_VP9_TREECODER_H_
|
|
#define VP9_COMMON_VP9_TREECODER_H_
|
|
|
|
typedef unsigned char vp9_prob;
|
|
|
|
#define vp9_prob_half ( (vp9_prob) 128)
|
|
|
|
typedef signed char vp9_tree_index;
|
|
struct bool_coder_spec;
|
|
|
|
typedef struct bool_coder_spec bool_coder_spec;
|
|
typedef struct bool_writer bool_writer;
|
|
typedef struct bool_reader bool_reader;
|
|
|
|
typedef const bool_coder_spec c_bool_coder_spec;
|
|
typedef const bool_writer c_bool_writer;
|
|
typedef const bool_reader c_bool_reader;
|
|
|
|
|
|
|
|
# define vp9_complement( x) (255 - x)
|
|
|
|
|
|
/* We build coding trees compactly in arrays.
|
|
Each node of the tree is a pair of vp9_tree_indices.
|
|
Array index often references a corresponding probability table.
|
|
Index <= 0 means done encoding/decoding and value = -Index,
|
|
Index > 0 means need another bit, specification at index.
|
|
Nonnegative indices are always even; processing begins at node 0. */
|
|
|
|
typedef const vp9_tree_index vp9_tree[], *vp9_tree_p;
|
|
|
|
|
|
typedef const struct vp9_token_struct {
|
|
int value;
|
|
int Len;
|
|
} vp9_token;
|
|
|
|
/* Construct encoding array from tree. */
|
|
|
|
void vp9_tokens_from_tree(struct vp9_token_struct *, vp9_tree);
|
|
void vp9_tokens_from_tree_offset(struct vp9_token_struct *, vp9_tree,
|
|
int offset);
|
|
|
|
|
|
/* Convert array of token occurrence counts into a table of probabilities
|
|
for the associated binary encoding tree. Also writes count of branches
|
|
taken for each node on the tree; this facilitiates decisions as to
|
|
probability updates. */
|
|
|
|
void vp9_tree_probs_from_distribution(
|
|
int n, /* n = size of alphabet */
|
|
vp9_token tok [ /* n */ ],
|
|
vp9_tree tree,
|
|
vp9_prob probs [ /* n-1 */ ],
|
|
unsigned int branch_ct [ /* n-1 */ ] [2],
|
|
const unsigned int num_events[ /* n */ ],
|
|
unsigned int Pfactor,
|
|
int Round
|
|
);
|
|
|
|
static __inline int clip_prob(int p) {
|
|
if (p > 255)
|
|
return 255;
|
|
else if (p < 1)
|
|
return 1;
|
|
return p;
|
|
}
|
|
|
|
vp9_prob vp9_bin_prob_from_distribution(const unsigned int counts[2]);
|
|
|
|
#endif
|