diff -r 000000000000 -r 40261b775718 mmlibs/mmfw/Codecs/Src/MMFCodecCommon/MMFAudioSPcm16ToALawCodec.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mmlibs/mmfw/Codecs/Src/MMFCodecCommon/MMFAudioSPcm16ToALawCodec.cpp Tue Feb 02 01:56:55 2010 +0200 @@ -0,0 +1,89 @@ +// Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies). +// All rights reserved. +// This component and the accompanying materials are made available +// under the terms of "Eclipse Public License v1.0" +// which accompanies this distribution, and is available +// at the URL "http://www.eclipse.org/legal/epl-v10.html". +// +// Initial Contributors: +// Nokia Corporation - initial contribution. +// +// Contributors: +// +// Description: +// + +#include "MMFAudioSPcm16ToALawCodec.h" + +/*** +* +* Convert +* +*/ +EXPORT_C void TMMFAudioSPcm16ToAlawCodec::Convert(TUint8* aSrc, TUint8* aDst, TInt aSamples) + { + TInt16* pcm = (TInt16*)aSrc; + TInt16* pcmLimit = pcm + aSamples; + + while (pcm < pcmLimit) + { + *aDst++ = PcmSampleToAlaw(*pcm++); + } + + } + +//[ conversion look up table pcm16 to alaw ] +const TInt8 TMMFAudioSPcm16ToAlawCodec::KExpLut[] = + { + 1,1,2,2,3,3,3,3, + 4,4,4,4,4,4,4,4, + 5,5,5,5,5,5,5,5, + 5,5,5,5,5,5,5,5, + 6,6,6,6,6,6,6,6, + 6,6,6,6,6,6,6,6, + 6,6,6,6,6,6,6,6, + 6,6,6,6,6,6,6,6, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7 + }; + +/*** +* +* PcmSampleToAlaw +* @param aLaw +* @return TUint8 +* +*/ +TUint8 TMMFAudioSPcm16ToAlawCodec::PcmSampleToAlaw(TInt aPcm) + { + TInt sign; + TInt exponent; + TInt mantissa; + TUint8 alawbyte; + + sign = ((~aPcm) >> 8) & KMaskSign8bit; + if (sign == 0) + aPcm = -aPcm; + if (aPcm > KMda16PcmToAlawClip) + aPcm = KMda16PcmToAlawClip; + + if (aPcm >= 256) + { + exponent = KExpLut[( aPcm >> 8 ) & 0x7F]; + mantissa = ( aPcm >> ( exponent + 3 ) ) & 0x0F; + alawbyte = STATIC_CAST( TUint8, (( exponent << 4 ) | mantissa)); + } + else + alawbyte = STATIC_CAST( TUint8, aPcm >> 4); + + alawbyte ^= (sign ^ 0x55); + + return alawbyte; + } +