aom/aom_dsp/entcode.h

47 строки
1.6 KiB
C

/*
* Copyright (c) 2001-2016, 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.
*/
#if !defined(_entcode_H)
#define _entcode_H (1)
#include <limits.h>
#include <stddef.h>
#include "av1/common/odintrin.h"
/*OPT: od_ec_window must be at least 32 bits, but if you have fast arithmetic
on a larger type, you can speed up the decoder by using it here.*/
typedef uint32_t od_ec_window;
#define OD_EC_WINDOW_SIZE ((int)sizeof(od_ec_window) * CHAR_BIT)
/*The number of bits to use for the range-coded part of unsigned integers.*/
#define OD_EC_UINT_BITS (4)
/*The resolution of fractional-precision bit usage measurements, i.e.,
3 => 1/8th bits.*/
#define OD_BITRES (3)
/*With CONFIG_EC_SMALLMUL, the value stored in a CDF is 32768 minus the actual
Q15 cumulative probability (an "inverse" CDF).
This function converts from one representation to the other (and is its own
inverse).*/
#if CONFIG_EC_SMALLMUL
#define OD_ICDF(x) (32768U - (x))
#else
#define OD_ICDF(x) (x)
#endif
/*See entcode.c for further documentation.*/
OD_WARN_UNUSED_RESULT uint32_t od_ec_tell_frac(uint32_t nbits_total,
uint32_t rng);
#endif