#ifndef MATHEMATICS_H#define MATHEMATICS_H#include "rational.h"enum AVRounding {    AV_ROUND_ZERO     = 0, ///< round toward zero    AV_ROUND_INF      = 1, ///< round away from zero    AV_ROUND_DOWN     = 2, ///< round toward -infinity    AV_ROUND_UP       = 3, ///< round toward +infinity    AV_ROUND_NEAR_INF = 5, ///< round to nearest and halfway cases away from zero};/** * rescale a 64bit integer with rounding to nearest. * a simple a*b/c isn't possible as it can overflow */int64_t av_rescale(int64_t a, int64_t b, int64_t c);/** * rescale a 64bit integer with specified rounding. * a simple a*b/c isn't possible as it can overflow */int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding);/** * rescale a 64bit integer by 2 rational numbers. */int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq);#endif /* MATHEMATICS_H */