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ffmpeg-4.2.2/libavfilter/hermite.h 1.35 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #ifndef AVFILTER_HERMITE_H
  #define AVFILTER_HERMITE_H
  
  static inline double hermite_interpolation(double x, double x0, double x1,
                                      double p0, double p1,
                                      double m0, double m1)
  {
      double width = x1 - x0;
      double t = (x - x0) / width;
      double t2, t3;
      double ct0, ct1, ct2, ct3;
  
      m0 *= width;
      m1 *= width;
  
      t2 = t*t;
      t3 = t2*t;
      ct0 = p0;
      ct1 = m0;
  
      ct2 = -3 * p0 - 2 * m0 + 3 * p1 - m1;
      ct3 = 2 * p0 + m0  - 2 * p1 + m1;
  
      return ct3 * t3 + ct2 * t2 + ct1 * t + ct0;
  }
  
  #endif /* AVFILTER_HERMITE_H */