ffmpeg / libavutil / mathematics.h @ d1a12956
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/*


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* copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>

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*

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* This file is part of FFmpeg.

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*

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* FFmpeg is free software; you can redistribute it and/or

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* modify it under the terms of the GNU Lesser General Public

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* License as published by the Free Software Foundation; either

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* version 2.1 of the License, or (at your option) any later version.

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*

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* FFmpeg is distributed in the hope that it will be useful,

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* but WITHOUT ANY WARRANTY; without even the implied warranty of

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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

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* Lesser General Public License for more details.

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*

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* You should have received a copy of the GNU Lesser General Public

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* License along with FFmpeg; if not, write to the Free Software

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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 021101301 USA

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*/

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#ifndef FFMPEG_MATHEMATICS_H

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#define FFMPEG_MATHEMATICS_H

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#include <stdint.h> 
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#include <math.h> 
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#include "rational.h" 
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#ifndef M_E

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#define M_E 2.7182818284590452354 /* e */ 
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#endif

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#ifndef M_LN2

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#define M_LN2 0.69314718055994530942 /* log_e 2 */ 
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#endif

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#ifndef M_LN10

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#define M_LN10 2.30258509299404568402 /* log_e 10 */ 
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#endif

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#ifndef M_SQRT1_2

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#define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */ 
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#endif

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enum AVRounding {

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AV_ROUND_ZERO = 0, ///< round toward zero 
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AV_ROUND_INF = 1, ///< round away from zero 
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AV_ROUND_DOWN = 2, ///< round toward infinity 
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AV_ROUND_UP = 3, ///< round toward +infinity 
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AV_ROUND_NEAR_INF = 5, ///< round to nearest and halfway cases away from zero 
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}; 
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/**

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* rescale a 64bit integer with rounding to nearest.

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* a simple a*b/c isn't possible as it can overflow

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*/

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int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const; 
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/**

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* rescale a 64bit integer with specified rounding.

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* a simple a*b/c isn't possible as it can overflow

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*/

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int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;

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/**

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* rescale a 64bit integer by 2 rational numbers.

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*/

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int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const; 
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#endif /* FFMPEG_MATHEMATICS_H */ 