diff -r 000000000000 -r bde4ae8d615e os/mm/mmlibs/mmfw/Codecs/Src/MMFCodecCommon/MMFAudioImaAdpcmToS16Codec.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/os/mm/mmlibs/mmfw/Codecs/Src/MMFCodecCommon/MMFAudioImaAdpcmToS16Codec.cpp Fri Jun 15 03:10:57 2012 +0200 @@ -0,0 +1,121 @@ +// 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: +// MMFAudioImaAdpcmToS16PcmCodec.cpp +// +// + +#include "MMFAudioImaAdpcmToS16PcmCodec.h" + +/** +* +* Convert +* @param aSrc +* @param aDst +* @param aSamples +* +*/ +EXPORT_C void TMMFAudioImaAdpcmToS16PcmCodec::Convert(TUint8* aSrc, TUint8* aDst, TInt aSamples) + { + TInt delta; // Current adpcm output value + TInt step; // Stepsize + TInt valpred; // Predicted value + TInt vpdiff; // Current change to valpred + TInt index; // Current step change index + + //[Read first sample and index from block header + // we do not need to store the information across calls + //since we process the entire block here] + valpred = (*aSrc++) & KAndMask8bit; + valpred |= STATIC_CAST(TInt16, ((*aSrc++) << 8)); + index = *aSrc++; + TUint8* dst=aDst; + + aSrc++; //skip reserved header byte + + //Write first sample to dest + *aDst++ = STATIC_CAST( TUint8, valpred); + *aDst++ = STATIC_CAST( TUint8, valpred >> 8); + dst += 2; + aSamples --; + + TBool theBufferStep = ETrue; + TInt bufferValue = 0; + for ( ; aSamples > 0 ; aSamples-- ) + { + // Step 1 - get the delta value + if ( theBufferStep) + { + bufferValue = *aSrc++; + delta = bufferValue & 0xf; + } + else + { + delta = (bufferValue >> 4) & 0xf; + } + + theBufferStep = !theBufferStep; + + ASSERT(index >= 0); + step = KStepSizeTable[index]; + + vpdiff = step>>3; + if ( delta & 4 ) + vpdiff += step; + if ( delta & 2 ) + vpdiff += step>>1; + if ( delta & 1 ) + vpdiff += step>>2; + + if ( delta & 8 ) + valpred -= vpdiff; + else + valpred += vpdiff; + + if ( valpred > (KClamp - 1) ) + valpred = (KClamp - 1); + else if ( valpred < -KClamp ) + valpred = -KClamp; + + index += KIndexTable[delta]; + if ( index < 0 ) + index = 0; + if ( index > KMaxImaAdpcmTableEntries ) + index = KMaxImaAdpcmTableEntries; + + *dst++ = STATIC_CAST( TUint8, valpred&KAndMask8bit); + *dst++ = STATIC_CAST( TUint8, (valpred>>8) ); + } + } + + + +// IMA-ADPCM step variation table +const TInt TMMFAudioImaAdpcmToS16PcmCodec::KIndexTable[] = + { + -1, -1, -1, -1, 2, 4, 6, 8, + -1, -1, -1, -1, 2, 4, 6, 8 + }; + +const TInt TMMFAudioImaAdpcmToS16PcmCodec::KStepSizeTable[89] = + { + 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, + 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, + 50, 55, 60, 66, 73, 80, 88, 97, 107, 118, + 130, 143, 157, 173, 190, 209, 230, 253, 279, 307, + 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, + 876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, + 2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358, + 5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, + 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767 + };