lavc: G.723.1 encoder
[libav.git] / libavcodec / celp_math.h
1 /*
2 * Various fixed-point math operations
3 *
4 * Copyright (c) 2008 Vladimir Voroshilov
5 *
6 * This file is part of Libav.
7 *
8 * Libav is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * Libav is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #ifndef AVCODEC_CELP_MATH_H
24 #define AVCODEC_CELP_MATH_H
25
26 #include <stdint.h>
27
28 /**
29 * fixed-point implementation of exp2(x) in [0; 1] domain.
30 * @param power argument to exp2, 0 <= power <= 0x7fff
31 *
32 * @return value of (1<<20) * exp2(power / (1<<15))
33 * 0x8000c <= result <= 0xfffea
34 */
35 int ff_exp2(uint16_t power);
36
37 /**
38 * Calculate log2(x).
39 * @param value function argument, 0 < value <= 7fff ffff
40 *
41 * @return value of (1<<15) * log2(value)
42 */
43 int ff_log2_q15(uint32_t value);
44
45 /**
46 * Calculate the dot product of 2 int16_t vectors.
47 * @param a input data array
48 * @param b input data array
49 * @param length number of elements
50 *
51 * @return dot product = sum of elementwise products
52 */
53 int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length);
54
55 /**
56 * Shift value left or right depending on sign of offset parameter.
57 * @param value value to shift
58 * @param offset shift offset
59 *
60 * @return value << offset, if offset>=0; value >> -offset - otherwise
61 */
62 static inline int bidir_sal(int value, int offset)
63 {
64 if(offset < 0) return value >> -offset;
65 else return value << offset;
66 }
67
68 #endif /* AVCODEC_CELP_MATH_H */