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// Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).
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// All rights reserved.
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// This component and the accompanying materials are made available
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// under the terms of "Eclipse Public License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.eclipse.org/legal/epl-v10.html".
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//
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// Initial Contributors:
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// Nokia Corporation - initial contribution.
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//
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// Contributors:
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//
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// Description:
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//
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#include "MMFAudioSPcm16ToMuLawCodec.h"
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/***
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*
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* Convert
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*
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*/
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EXPORT_C void TMMFAudioSPcm16ToMuLawCodec::Convert(TUint8* aSrc, TUint8* aDst, TInt aSamples)
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{
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TInt pcm;
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while (aSamples--)
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{
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pcm = (aSrc[0]+(aSrc[1]<<8));
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*aDst++ = PcmSampleToMuLaw(STATIC_CAST(TInt16 , pcm));
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aSrc+=2;
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}
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}
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//[ conversion look up table pcm16 to Mulaw ]
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const TInt8 TMMFAudioSPcm16ToMuLawCodec::KExpLut[] =
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{
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0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,
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4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
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5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
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5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
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};
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/***
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*
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* PcmSampleToMulaw
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* @param Mulaw
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* @return TUint8
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*
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*/
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TUint8 TMMFAudioSPcm16ToMuLawCodec::PcmSampleToMuLaw(TInt aPcm)
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{
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TInt sign, exponent, mantissa;
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TUint8 ulawbyte;
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sign = (aPcm >> 8) & KMaskSign8bit;
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if ( sign != 0 )
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aPcm = STATIC_CAST( TUint16,-aPcm);
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if ( STATIC_CAST(TUint , aPcm) > STATIC_CAST(TUint , KMda16PcmToMulawClip ))
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aPcm = KMda16PcmToMulawClip;
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aPcm = STATIC_CAST(TInt16 , aPcm + KMda16PcmToMulawBias);
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exponent = KExpLut[( aPcm >> 7 ) & KAndMask8bit];
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mantissa = ( aPcm >> ( exponent + 3 ) ) & 0x0F;
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ulawbyte = STATIC_CAST( TUint8, ~ ( sign | ( exponent << 4 ) | mantissa ));
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return ulawbyte;
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}
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