27 #ifndef AVUTIL_MATHEMATICS_H 28 #define AVUTIL_MATHEMATICS_H 37 #define M_E 2.7182818284590452354 40 #define M_LN2 0.69314718055994530942 43 #define M_LN10 2.30258509299404568402 46 #define M_LOG2_10 3.32192809488736234787 49 #define M_PHI 1.61803398874989484820 52 #define M_PI 3.14159265358979323846 55 #define M_PI_2 1.57079632679489661923 58 #define M_SQRT1_2 0.70710678118654752440 61 #define M_SQRT2 1.41421356237309504880 64 #define NAN av_int2float(0x7fc00000) 67 #define INFINITY av_int2float(0x7f800000)
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
AVRounding
Rounding methods.
Macro definitions for various function/variable attributes.
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const
Rescale a 64-bit integer by 2 rational numbers.
Round to nearest and halfway cases away from zero.
int64_t av_const av_gcd(int64_t a, int64_t b)
Compute the greatest common divisor of two integer operands.
int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b)
Compare two timestamps each in its own time base.
int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const
Rescale a 64-bit integer with rounding to nearest.
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd) av_const
Rescale a 64-bit integer with specified rounding.
int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts, AVRational fs_tb, int duration, int64_t *last, AVRational out_tb)
Rescale a timestamp while preserving known durations.
static int mod(int a, int b)
Modulo operation with only positive remainders.
Rational number (pair of numerator and denominator).
Utilties for rational number calculation.
int64_t av_add_stable(AVRational ts_tb, int64_t ts, AVRational inc_tb, int64_t inc)
Add a value to a timestamp.
Flag telling rescaling functions to pass INT64_MIN/MAX through unchanged, avoiding special cases for ...
int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq, enum AVRounding rnd) av_const
Rescale a 64-bit integer by 2 rational numbers with specified rounding.
int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod)
Compare the remainders of two integer operands divided by a common divisor.