1 /* 2 * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 module ffmpeg.libavutil.mathematics; 21 import std.stdint; 22 import ffmpeg.libavutil.rational; 23 import ffmpeg.libavutil.intfloat; 24 25 enum M_E = 2.7182818284590452354; /* e */ 26 enum M_LN2 = 0.69314718055994530942; /* log_e 2 */ 27 enum M_LN10 = 2.30258509299404568402; /* log_e 10 */ 28 enum M_LOG2_10 = 3.32192809488736234787; /* log_2 10 */ 29 enum M_PHI = 1.61803398874989484820; /* phi / golden ratio */ 30 enum M_PI = 3.14159265358979323846; /* pi */ 31 enum M_PI_2 = 1.57079632679489661923; /* pi/2 */ 32 enum M_SQRT1_2 = 0.70710678118654752440; /* 1/sqrt(2) */ 33 enum M_SQRT2 = 1.41421356237309504880; /* sqrt(2) */ 34 enum NAN = av_int2float(0x7fc00000); 35 enum INFINITY = av_int2float(0x7f800000); 36 37 @nogc nothrow extern(C): 38 39 /** 40 * @addtogroup lavu_math 41 * @{ 42 */ 43 enum AVRounding { 44 AV_ROUND_ZERO = 0, ///< Round toward zero. 45 AV_ROUND_INF = 1, ///< Round away from zero. 46 AV_ROUND_DOWN = 2, ///< Round toward -infinity. 47 AV_ROUND_UP = 3, ///< Round toward +infinity. 48 AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero. 49 AV_ROUND_PASS_MINMAX = 8192 ///< Flag to pass INT64_MIN/MAX through instead of rescaling, this avoids special cases for AV_NOPTS_VALUE 50 } 51 52 /** 53 * Compute the greatest common divisor of a and b. 54 * 55 * @return gcd of a and b up to sign; if a >= 0 and b >= 0, return value is >= 0; 56 * if a == 0 and b == 0, returns 0. 57 */ 58 int64_t av_gcd(int64_t a, int64_t b); 59 60 /** 61 * Rescale a 64-bit integer with rounding to nearest. 62 * A simple a*b/c isn't possible as it can overflow. 63 */ 64 int64_t av_rescale(int64_t a, int64_t b, int64_t c); 65 66 /** 67 * Rescale a 64-bit integer with specified rounding. 68 * A simple a*b/c isn't possible as it can overflow. 69 * 70 * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is 71 * INT64_MIN or INT64_MAX then a is passed through unchanged. 72 */ 73 int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, AVRounding); 74 75 /** 76 * Rescale a 64-bit integer by 2 rational numbers. 77 */ 78 int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq); 79 80 /** 81 * Rescale a 64-bit integer by 2 rational numbers with specified rounding. 82 * 83 * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is 84 * INT64_MIN or INT64_MAX then a is passed through unchanged. 85 */ 86 int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq, 87 AVRounding); 88 89 /** 90 * Compare 2 timestamps each in its own timebases. 91 * The result of the function is undefined if one of the timestamps 92 * is outside the int64_t range when represented in the others timebase. 93 * @return -1 if ts_a is before ts_b, 1 if ts_a is after ts_b or 0 if they represent the same position 94 */ 95 int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b); 96 97 /** 98 * Compare 2 integers modulo mod. 99 * That is we compare integers a and b for which only the least 100 * significant log2(mod) bits are known. 101 * 102 * @param mod must be a power of 2 103 * @return a negative value if a is smaller than b 104 * a positive value if a is greater than b 105 * 0 if a equals b 106 */ 107 int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod); 108 109 /** 110 * Rescale a timestamp while preserving known durations. 111 * 112 * @param in_ts Input timestamp 113 * @param in_tb Input timesbase 114 * @param fs_tb Duration and *last timebase 115 * @param duration duration till the next call 116 * @param out_tb Output timesbase 117 */ 118 int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts, AVRational fs_tb, int duration, int64_t *last, AVRational out_tb); 119 120 121 /** 122 * Add a value to a timestamp. 123 * 124 * This function guarantees that when the same value is repeatly added that 125 * no accumulation of rounding errors occurs. 126 * 127 * @param ts Input timestamp 128 * @param ts_tb Input timestamp timebase 129 * @param inc value to add to ts 130 * @param inc_tb inc timebase 131 */ 132 int64_t av_add_stable(AVRational ts_tb, int64_t ts, AVRational inc_tb, int64_t inc); 133 134 /** 135 * @} 136 */