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speed optimization with the channel levels in the server

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This commit is contained in:
Volker Fischer 2020-06-23 18:07:14 +02:00
parent f3eb0b3baa
commit 68a9fc7c7e
1 changed files with 13 additions and 8 deletions
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19
src/server.cpp
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@ -1680,29 +1680,34 @@ bool CServer::CreateLevelsForAllConChannels ( const int i
// get a reference to the audio data
const CVector<int16_t>& vecsData = vecvecsData[j];
double dCurLevel = 0.0;
// Speed optimization:
// - we only make use of the positive values and ignore the negative ones
// -> we do not need to call the fabs() function
// - we only evaluate every third sample
int16_t sMax = 0;
if ( vecNumAudioChannels[j] == 1 )
{
// mono
for ( i = 0; i < iServerFrameSizeSamples; i += 3 )
{
dCurLevel = std::max ( dCurLevel, fabs ( static_cast<double> ( vecsData[i] ) ) );
sMax = std::max ( sMax, vecsData[i] );
}
}
else
{
// stereo: apply stereo-to-mono attenuation
for ( i = 0, k = 0; i < iServerFrameSizeSamples; i += 3, k += 6 )
// stereo
for ( i = 0, k = 0; i < iServerFrameSizeSamples; i += 3, k += 6 ) // 2 * 3 = 6 -> stereo
{
double sMix = ( static_cast<double> ( vecsData[k] ) + vecsData[k + 1] ) / 2;
dCurLevel = std::max ( dCurLevel, fabs ( sMix ) );
// left/right channels separately
sMax = std::max ( sMax, vecsData[k] );
sMax = std::max ( sMax, vecsData[k + 1] );
}
}
// smoothing
const int iChId = vecChanIDsCurConChan[j];
dCurLevel = std::max ( dCurLevel, vecChannels[iChId].GetPrevLevel() * 0.5 );
const double dCurLevel = std::max ( static_cast<double> ( sMax ), vecChannels[iChId].GetPrevLevel() * 0.5 );
vecChannels[iChId].SetPrevLevel ( dCurLevel );
// logarithmic measure