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