xbmc/utils/BitstreamStats.cpp

   1 /*
   2  *      Copyright (C) 2005-2008 Team XBMC
   3  *      http://www.xbmc.org
   4  *
   5  *  This Program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2, or (at your option)
   8  *  any later version.
   9  *
  10  *  This Program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with XBMC; see the file COPYING.  If not, write to
  17  *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  18  *  http://www.gnu.org/copyleft/gpl.html
  19  *
  20  */
  21
  22 #include "BitstreamStats.h"
  23 #include "utils/TimeUtils.h"
  24
  25 int64_t BitstreamStats::m_tmFreq;
  26
  27 BitstreamStats::BitstreamStats(unsigned int nEstimatedBitrate)
  28 {
  29   m_dBitrate = 0.0;
  30   m_dMaxBitrate = 0.0;
  31   m_dMinBitrate = -1.0;
  32
  33   m_nBitCount = 0;
  34   m_nEstimatedBitrate = nEstimatedBitrate;
  35   m_tmStart = 0LL;
  36
  37   if (m_tmFreq == 0LL)
  38     m_tmFreq = CurrentHostFrequency();
  39 }
  40
  41 BitstreamStats::~BitstreamStats()
  42 {
  43 }
  44
  45 void BitstreamStats::AddSampleBytes(unsigned int nBytes)
  46 {
  47   AddSampleBits(nBytes*8);
  48 }
  49
  50 void BitstreamStats::AddSampleBits(unsigned int nBits)
  51 {
  52   m_nBitCount += nBits;
  53   if (m_nBitCount >= m_nEstimatedBitrate)
  54     CalculateBitrate();
  55 }
  56
  57 void BitstreamStats::Start()
  58 {
  59   m_nBitCount = 0;
  60   m_tmStart = CurrentHostCounter();
  61 }
  62
  63 void BitstreamStats::CalculateBitrate()
  64 {
  65   int64_t tmNow;
  66   tmNow = CurrentHostCounter();
  67
  68   double elapsed = (double)(tmNow - m_tmStart) / (double)m_tmFreq;
  69   // only update once every 2 seconds
  70   if (elapsed >= 2)
  71   {
  72     m_dBitrate = (double)m_nBitCount / elapsed;
  73
  74     if (m_dBitrate > m_dMaxBitrate)
  75       m_dMaxBitrate = m_dBitrate;
  76
  77     if (m_dBitrate < m_dMinBitrate || m_dMinBitrate == -1)
  78       m_dMinBitrate = m_dBitrate;
  79
  80     Start();
  81   }
  82 }
  83
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  86