45 строки
1.3 KiB
C
45 строки
1.3 KiB
C
/*
|
|
* Copyright (c) 2016, Alliance for Open Media. All rights reserved
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef AOM_DSP_ANS_H_
|
|
#define AOM_DSP_ANS_H_
|
|
// Constants, types and utilities for Asymmetric Numeral Systems
|
|
// http://arxiv.org/abs/1311.2540v2
|
|
|
|
#include <assert.h>
|
|
#include "./aom_config.h"
|
|
#include "aom/aom_integer.h"
|
|
#include "aom_dsp/prob.h"
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif // __cplusplus
|
|
|
|
// Use windowed ANS, size is passed in at initialization
|
|
#define ANS_MAX_SYMBOLS 1
|
|
#define ANS_REVERSE 1
|
|
|
|
typedef uint8_t AnsP8;
|
|
#define ANS_P8_PRECISION 256u
|
|
#define ANS_P8_SHIFT 8
|
|
#define RANS_PROB_BITS 15
|
|
#define RANS_PRECISION (1u << RANS_PROB_BITS)
|
|
|
|
// L_BASE is the ANS base state. L_BASE % PRECISION must be 0.
|
|
#define L_BASE (1u << 17)
|
|
#define IO_BASE 256
|
|
// Range I = { L_BASE, L_BASE + 1, ..., L_BASE * IO_BASE - 1 }
|
|
|
|
#ifdef __cplusplus
|
|
} // extern "C"
|
|
#endif // __cplusplus
|
|
#endif // AOM_DSP_ANS_H_
|