fpschanger.cpp

   1 #include "fpschanger.hpp"
   2
   3 fpschanger::fpschanger(uint32_t _tfps_n, uint32_t _tfps_d, uint32_t sfps_n, uint32_t sfps_d)
   4 {
   5         if(!_tfps_n || !_tfps_d) {
   6                 _tfps_n = 25;
   7                 _tfps_d = 1;
   8         }
   9         if(!sfps_n || !sfps_d) {
  10                 sfps_n = 25;
  11                 sfps_d = 1;
  12         }
  13         tfps_n = _tfps_n;
  14         tfps_d = _tfps_d;
  15         increment = static_cast<uint64_t>(tfps_n) * sfps_d;
  16         decrement = static_cast<uint64_t>(tfps_d) * sfps_n;
  17         balance = 0;
  18 }
  19
  20 void fpschanger::change_source_rate(uint32_t sfps_n, uint32_t sfps_d)
  21 {
  22         if(!sfps_n || !sfps_d) {
  23                 sfps_n = 25;
  24                 sfps_d = 1;
  25         }
  26         uint64_t old_increment = increment;
  27         increment = static_cast<uint64_t>(tfps_n) * sfps_d;
  28         decrement = static_cast<uint64_t>(tfps_d) * sfps_n;
  29         //We have to adjust balance by ratio of new and old incrments.
  30         balance = 1.0 * increment / old_increment * balance + 0.5;
  31 }
  32
  33 uint64_t fpschanger::duration(uint64_t sduration)
  34 {
  35         uint64_t count = 0;
  36         //FIXME: Do this faster.
  37         for(uint64_t i = 0; i < sduration; i++) {
  38                 balance += increment;
  39                 while(balance > 0) {
  40                         count++;
  41                         balance -= decrement;
  42                 }
  43         }
  44         return count;
  45 }