Src/DasherCore/FrameRate.cpp

   1 #include "FrameRate.h"
   2
   3 using namespace Dasher;
   4
   5 CFrameRate::CFrameRate(CSettingsUser *pCreator) :
   6   CSettingsUserObserver(pCreator) {
   7
   8   //Sampling parameters...
   9   m_iFrames = 0;
  10   m_iSamples = 1;
  11   m_iTime = 0;
  12
  13   //try and carry on from where we left off at last run
  14   HandleEvent(LP_X_LIMIT_SPEED);
  15   //Sets m_dBitsAtLimX and m_iSteps
  16 }
  17
  18 void CFrameRate::RecordFrame(unsigned long Time)
  19 {
  20   m_iFrames++;
  21
  22   // Update values once enough samples have been collected
  23   if(m_iFrames == m_iSamples) {
  24     unsigned long m_iTime2 = Time;
  25
  26     // If samples are collected in < 50ms, collect more
  27     if(m_iTime2 - m_iTime < 50)
  28       m_iSamples++;
  29     // And if it's taking longer than > 80ms, collect fewer, down to a
  30     // limit of 2
  31     else if(m_iTime2 - m_iTime > 80) {
  32       m_iSamples--;
  33       if(m_iSamples < 2)
  34         m_iSamples = 2;
  35     }
  36
  37     // Calculate the framerate and reset framerate statistics for next
  38     // sampling period
  39     if(m_iTime2 - m_iTime > 0) {
  40       double dFrNow = m_iFrames * 1000.0 / (m_iTime2 - m_iTime);
  41       //LP_FRAMERATE records a decaying average, smoothed 50:50 with previous value
  42       SetLongParameter(LP_FRAMERATE, long(GetLongParameter(LP_FRAMERATE) + (dFrNow*100))/2);
  43       m_iTime = m_iTime2;
  44       m_iFrames = 0;
  45
  46     DASHER_TRACEOUTPUT("Fr %f Steps %d Samples %d Time2 %d\n", dFrNow, m_iSteps, m_iSamples, m_iTime2);
  47
  48     }
  49
  50   }
  51 }
  52
  53 void CFrameRate::HandleEvent(int iParameter) {
  54   switch (iParameter) {
  55     case LP_X_LIMIT_SPEED:
  56       m_dBitsAtLimX = (log(static_cast<double>(CDasherModel::MAX_Y)) - log (2.*GetLongParameter(LP_X_LIMIT_SPEED)))/log(2.);
  57       //fallthrough
  58     case LP_MAX_BITRATE:
  59     case LP_FRAMERATE:
  60     //Calculate m_iSteps from the decaying-average framerate, as the number
  61     // of steps that, at the X limit, will cause LP_MAX_BITRATE bits to be
  62     // entered per second
  63     m_iSteps = std::max(1,(int)(GetLongParameter(LP_FRAMERATE)*m_dBitsAtLimX/GetLongParameter(LP_MAX_BITRATE)));
  64   }
  65 }