ans.h 1.44 KB
Newer Older
1
/*
2
 * Copyright (c) 2016, Alliance for Open Media. All rights reserved
3
 *
4
5
6
7
8
9
 * This source code is subject to the terms of the BSD 2 Clause License and
 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
 * was not distributed with this source code in the LICENSE file, you can
 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10
11
 */

Alex Converse's avatar
Alex Converse committed
12
13
#ifndef AOM_DSP_ANS_H_
#define AOM_DSP_ANS_H_
14
// Constants, types and utilities for Asymmetric Numeral Systems
15
16
// http://arxiv.org/abs/1311.2540v2

Alex Converse's avatar
Alex Converse committed
17
#include <assert.h>
Yaowu Xu's avatar
Yaowu Xu committed
18
19
#include "./aom_config.h"
#include "aom/aom_integer.h"
20
#include "aom_dsp/prob.h"
21
22
23
24
25
26

#ifdef __cplusplus
extern "C" {
#endif  // __cplusplus

typedef uint8_t AnsP8;
27
28
#define ANS_P8_PRECISION 256u
#define ANS_P8_SHIFT 8
29
30
#define RANS_PROB_BITS 15
#define RANS_PRECISION (1u << RANS_PROB_BITS)
31

32
33
34
// L_BASE % PRECISION must be 0. Increasing L_BASE beyond 2**15 will cause uabs
// to overflow.
#define L_BASE (RANS_PRECISION)
35
36
#define IO_BASE 256
// Range I = { L_BASE, L_BASE + 1, ..., L_BASE * IO_BASE - 1 }
37

Alex Converse's avatar
Alex Converse committed
38
39
40
void aom_rans_merge_prob8_pdf(aom_cdf_prob *const out_pdf,
                              const AnsP8 node_prob,
                              const aom_cdf_prob *const src_pdf, int in_syms);
41
42
43
#ifdef __cplusplus
}  // extern "C"
#endif  // __cplusplus
Alex Converse's avatar
Alex Converse committed
44
#endif  // AOM_DSP_ANS_H_