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//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================//
#include "audio_pch.h"
#include "minmax.h"
#include "voice_gain.h"
// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"
CAutoGain::CAutoGain()
{
Reset(128, 5.0f, 0.5f, 1);
}
void CAutoGain::Reset(int blockSize, float maxGain, float avgToMaxVal, float scale)
{
m_BlockSize = blockSize;
m_MaxGain = maxGain;
m_AvgToMaxVal = avgToMaxVal;
m_CurBlockOffset = 0;
m_CurTotal = 0;
m_CurMax = 0;
m_CurrentGain = 1;
m_NextGain = 1;
m_Scale = scale;
m_GainMultiplier = 0;
m_FixedCurrentGain = 1 << AG_FIX_SHIFT;
}
void CAutoGain::ProcessSamples(
short *pSamples,
int nSamples)
{
short *pCurPos = pSamples;
int nSamplesLeft = nSamples;
// Continue until we hit the end of this block.
while(nSamplesLeft)
{
int nToProcess = min(nSamplesLeft, (m_BlockSize - m_CurBlockOffset));
for(int iSample=0; iSample < nToProcess; iSample++)
{
// Update running totals..
m_CurTotal += abs( pCurPos[iSample] );
m_CurMax = max( m_CurMax, (int)abs( pCurPos[iSample] ) );
// Apply gain on this sample.
AGFixed gain = m_FixedCurrentGain + m_CurBlockOffset * m_GainMultiplier;
m_CurBlockOffset++;
int newval = ((int)pCurPos[iSample] * gain) >> AG_FIX_SHIFT;
newval = min(32767, max(newval, -32768));
pCurPos[iSample] = (short)newval;
}
pCurPos += nToProcess;
nSamplesLeft -= nToProcess;
// Did we just end a block? Update our next gain.
if((m_CurBlockOffset % m_BlockSize) == 0)
{
// Now we've interpolated to our next gain, make it our current gain.
m_CurrentGain = m_NextGain * m_Scale;
m_FixedCurrentGain = (int)((double)m_CurrentGain * (1 << AG_FIX_SHIFT));
// Figure out the next gain (the gain we'll interpolate to).
int avg = m_CurTotal / m_BlockSize;
float modifiedMax = avg + (m_CurMax - avg) * m_AvgToMaxVal;
m_NextGain = min(32767.0f / modifiedMax, m_MaxGain) * m_Scale;
// Setup the interpolation multiplier.
float fGainMultiplier = (m_NextGain - m_CurrentGain) / (m_BlockSize - 1);
m_GainMultiplier = (AGFixed)((double)fGainMultiplier * (1 << AG_FIX_SHIFT));
// Reset counters.
m_CurTotal = 0;
m_CurMax = 0;
m_CurBlockOffset = 0;
}
}
}
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