added MS-ADPCM
This commit is contained in:
Volker Fischer
parent
441e320e79
commit
83faac5a6d
3 changed files with 335 additions and 26 deletions
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@ -4,8 +4,8 @@
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* Author(s):
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* Volker Fischer, Erik de Castro Lopo
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*
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* This code is based on the Open-Source implementation of IMA-ADPCM written
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* by Erik de Castro Lopo <erikd[at-#]mega-nerd[dot*]com> in 1999-2004
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* This code is based on the Open-Source implementation of IMA-ADPCM / MS-ADPCM
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* written by Erik de Castro Lopo <erikd[at-#]mega-nerd[dot*]com> in 1999-2004
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*
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* Changes:
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* - only support for one channel
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@ -46,7 +46,11 @@ int CAudioCompression::Init ( const int iNewAudioLen,
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case CT_IMAADPCM:
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return ImaAdpcm.Init ( iNewAudioLen );
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default: return 0;
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case CT_MSADPCM:
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return MsAdpcm.Init ( iNewAudioLen );
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default:
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return 0;
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}
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}
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@ -60,7 +64,7 @@ CVector<unsigned char> CAudioCompression::Encode ( const CVector<short>& vecsAud
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for ( int i = 0; i < iAudSize; i++ )
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{
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vecbyOut[2 * i] = vecsAudio[i] & 0xFF;
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vecbyOut[2 * i] = vecsAudio[i] & 0xFF;
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vecbyOut[2 * i + 1] = ( vecsAudio[i] >> 8 ) & 0xFF;
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}
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return vecbyOut;
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@ -72,6 +76,9 @@ CVector<unsigned char> CAudioCompression::Encode ( const CVector<short>& vecsAud
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case CT_IMAADPCM:
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return ImaAdpcm.Encode ( vecsAudio ); // IMA-ADPCM
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case CT_MSADPCM:
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return MsAdpcm.Encode ( vecsAudio ); // MS-ADPCM
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default:
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return CVector<unsigned char> ( 0 );
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}
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@ -105,6 +112,9 @@ CVector<short> CAudioCompression::Decode ( const CVector<unsigned char>& vecbyAd
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case CT_IMAADPCM:
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return ImaAdpcm.Decode ( vecbyAdpcm ); // IMA-ADPCM
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case CT_MSADPCM:
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return MsAdpcm.Decode ( vecbyAdpcm ); // MS-ADPCM
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default:
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return CVector<short> ( 0 );
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}
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@ -112,7 +122,10 @@ CVector<short> CAudioCompression::Decode ( const CVector<unsigned char>& vecbyAd
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}
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/* IMA-ADPCM implementation ------------------------------------------------- */
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/******************************************************************************\
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* IMA-ADPCM implementation *
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\******************************************************************************/
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int CImaAdpcm::Init ( const int iNewAudioLen )
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{
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// set lengths for audio and compressed data
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@ -132,10 +145,11 @@ CVector<unsigned char> CImaAdpcm::Encode ( const CVector<short>& vecsAudio )
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CVector<unsigned char> vecbyAdpcmTemp;
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// init size
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vecbyAdpcm.Init ( iAdpcmSize );
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vecbyAdpcm.Init ( iAdpcmSize );
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vecbyAdpcmTemp.Init ( iAudSize );
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/* encode the block header ----------------------------------------------- */
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/* Encode the block header ---------------------------------------------- */
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vecbyAdpcm[0] = vecsAudio[0] & 0xFF;
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vecbyAdpcm[1] = ( vecsAudio[0] >> 8 ) & 0xFF;
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vecbyAdpcm[2] = iStepindEnc;
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@ -143,7 +157,7 @@ CVector<unsigned char> CImaAdpcm::Encode ( const CVector<short>& vecsAudio )
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int iPrevAudio = vecsAudio[0];
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/* encode the samples as 4 bit ------------------------------------------- */
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/* Encode the samples as 4 bit ------------------------------------------ */
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for ( i = 1; i < iAudSize; i++ )
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{
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// init diff and step
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@ -187,15 +201,15 @@ CVector<unsigned char> CImaAdpcm::Encode ( const CVector<short>& vecsAudio )
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iStepindEnc += ima_indx_adjust[bytecode];
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// check that values do not exceed the bounds
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iPrevAudio = CheckBounds ( iPrevAudio, _MINSHORT, _MAXSHORT );
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iPrevAudio = CheckBounds ( iPrevAudio, _MINSHORT, _MAXSHORT );
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iStepindEnc = CheckBounds ( iStepindEnc, 0, IMA_STEP_SIZE_TAB_LEN - 1 );
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// use the input buffer as an intermediate result buffer
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// use a temporary buffer as an intermediate result buffer
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vecbyAdpcmTemp[i] = bytecode;
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}
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/* pack the 4 bit encoded samples ---------------------------------------- */
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/* Pack the 4 bit encoded samples --------------------------------------- */
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// The first encoded audio sample is in header
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vecbyAdpcm[3] = vecbyAdpcmTemp[1] & 0x0F;
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@ -216,7 +230,7 @@ CVector<short> CImaAdpcm::Decode ( const CVector<unsigned char>& vecbyAdpcm )
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vecsAudio.Init ( iAudSize );
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/* read and check the block header --------------------------------------- */
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/* Read the block header ------------------------------------------------ */
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int current = vecbyAdpcm[0] | ( vecbyAdpcm[1] << 8 );
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if ( current & 0x8000 )
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{
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@ -230,10 +244,10 @@ CVector<short> CImaAdpcm::Decode ( const CVector<unsigned char>& vecbyAdpcm )
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vecsAudio[0] = current;
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/* --------------------------------------------------------------------------
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pull apart the packed 4 bit samples and store them in their correct sample
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positions */
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// The first encoded audio sample is in header
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/* -------------------------------------------------------------------------
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pull apart the packed 4 bit samples and store them in their correct
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sample positions */
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// the first encoded audio sample is in header
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vecsAudio[1] = vecbyAdpcm[3] & 0x0F;
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for ( i = 4; i < iAdpcmSize; i++ )
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@ -244,7 +258,7 @@ CVector<short> CImaAdpcm::Decode ( const CVector<unsigned char>& vecbyAdpcm )
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}
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/* decode the encoded 4 bit samples -------------------------------------- */
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/* Decode the encoded 4 bit samples ------------------------------------- */
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for ( i = 1; i < iAudSize; i++ )
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{
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const short bytecode = vecsAudio[i] & 0xF ;
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@ -286,3 +300,255 @@ CVector<short> CImaAdpcm::Decode ( const CVector<unsigned char>& vecbyAdpcm )
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return vecsAudio;
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}
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/******************************************************************************\
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* MS-ADPCM implementation *
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\******************************************************************************/
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/*
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MS ADPCM block layout:
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byte purpose
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0 block predictor [0..6]
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1,2 initial idelta (positive)
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3,4 sample 1
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5,6 sample 0
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7..n packed bytecodes
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*/
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int CMsAdpcm::Init ( const int iNewAudioLen )
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{
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// set lengths for audio and compressed data
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iAudSize = iNewAudioLen;
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iAdpcmSize = 7 /* bytes header */ + (int) ceil (
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(double) ( iAudSize - 2 /* first two samples are in header */ ) / 2 );
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return iAdpcmSize;
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}
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CVector<unsigned char> CMsAdpcm::Encode ( const CVector<short>& vecsAudio )
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{
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CVector<short> vecsAudioTemp;
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CVector<unsigned char> vecbyAdpcm;
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// init size
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vecsAudioTemp.Init ( iAudSize );
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vecbyAdpcm.Init ( iAdpcmSize );
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// copy input vector (because we want to overwrite it)
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vecsAudioTemp = vecsAudio;
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// choose predictor
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int bpred;
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int idelta;
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ChoosePredictor ( vecsAudio, bpred, idelta );
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/* Encode the block header ---------------------------------------------- */
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vecbyAdpcm[0] = bpred;
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vecbyAdpcm[1] = idelta & 0xFF;
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vecbyAdpcm[2] = ( idelta >> 8 ) & 0xFF;
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vecbyAdpcm[3] = vecsAudio[1] & 0xFF;
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vecbyAdpcm[4] = ( vecsAudio[1] >> 8 ) & 0xFF;
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vecbyAdpcm[5] = vecsAudio[0] & 0xFF;
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vecbyAdpcm[6] = ( vecsAudio[0] >> 8 ) & 0xFF;
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/* Encode the samples as 4 bit ------------------------------------------ */
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unsigned int blockindx = 7;
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unsigned char byte = 0;
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for ( int k = 2; k < iAudSize; k++ )
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{
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const int predict = ( vecsAudioTemp[k - 1] * ms_AdaptCoeff1[bpred] +
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vecsAudioTemp[k - 2] * ms_AdaptCoeff2[bpred] ) >> 8;
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int errordelta = ( vecsAudio[k] - predict ) / idelta;
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if ( errordelta < -8 )
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{
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errordelta = -8 ;
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}
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else
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{
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if (errordelta > 7)
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{
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errordelta = 7;
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}
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}
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int newsamp = predict + ( idelta * errordelta );
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if ( newsamp > 32767 )
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{
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newsamp = 32767;
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}
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else
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{
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if ( newsamp < -32768 )
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{
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newsamp = -32768;
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}
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}
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if ( errordelta < 0 )
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{
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errordelta += 0x10;
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}
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byte = ( byte << 4 ) | ( errordelta & 0xF );
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if ( k % 2 )
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{
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vecbyAdpcm[blockindx++] = byte;
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byte = 0;
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}
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idelta = ( idelta * ms_AdaptationTable[errordelta] ) >> 8;
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if ( idelta < 16 )
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{
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idelta = 16;
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}
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vecsAudioTemp[k] = newsamp;
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}
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return vecbyAdpcm;
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}
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CVector<short> CMsAdpcm::Decode ( const CVector<unsigned char>& vecbyAdpcm )
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{
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CVector<short> vecsAudio;
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short bytecode;
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vecsAudio.Init ( iAudSize );
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/* Read the block header ------------------------------------------------ */
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short bpred = vecbyAdpcm[0];
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if ( bpred >= 7 )
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{
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// no valid MS ADPCM stream, do not decode
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return vecsAudio;
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}
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short chan_idelta = vecbyAdpcm[1] | ( vecbyAdpcm[2] << 8 );
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vecsAudio[1] = vecbyAdpcm[3] | ( vecbyAdpcm[4] << 8 );
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vecsAudio[0] = vecbyAdpcm[5] | ( vecbyAdpcm[6] << 8 );
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/* -------------------------------------------------------------------------
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pull apart the packed 4 bit samples and store them in their correct
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sample positions */
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for ( int i = 7; i < iAdpcmSize; i++ )
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{
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bytecode = vecbyAdpcm[i];
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vecsAudio[2 * i - 12] = ( bytecode >> 4 ) & 0x0F;
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vecsAudio[2 * i - 11] = bytecode & 0x0F;
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}
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/* Decode the encoded 4 bit samples ------------------------------------- */
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for ( int k = 2; k < iAudSize; k ++ )
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{
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bytecode = vecsAudio[k] & 0xF;
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// compute next Adaptive Scale Factor (ASF)
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int idelta = chan_idelta;
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// => / 256 => FIXED_POINT_ADAPTATION_BASE == 256
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chan_idelta = ( ms_AdaptationTable[bytecode] * idelta ) >> 8;
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if ( chan_idelta < 16 )
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{
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chan_idelta = 16;
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}
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if ( bytecode & 0x8 )
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{
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bytecode -= 0x10;
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}
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// => / 256 => FIXED_POINT_COEFF_BASE == 256
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const int predict = ( ( vecsAudio[k - 1] * ms_AdaptCoeff1[bpred] ) +
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( vecsAudio[k - 2] * ms_AdaptCoeff2[bpred] ) ) >> 8;
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int current = ( bytecode * idelta ) + predict;
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if ( current > 32767 )
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{
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current = 32767 ;
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}
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else
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{
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if ( current < -32768 )
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{
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current = -32768;
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}
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}
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vecsAudio[k] = current;
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}
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return vecsAudio;
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}
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void CMsAdpcm::ChoosePredictor ( const CVector<short>& vecsAudio,
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int& block_pred,
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int& idelta )
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{
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/*
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Choosing the block predictor:
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Each block requires a predictor and an idelta for each channel. The
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predictor is in the range [0..6] which is an index into the two AdaptCoeff
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tables. The predictor is chosen by trying all of the possible predictors on
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a small set of samples at the beginning of the block. The predictor with the
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smallest average abs (idelta) is chosen as the best predictor for this
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block. The value of idelta is chosen to to give a 4 bit code value of +/- 4
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(approx. half the max. code value). If the average abs (idelta) is zero, the
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sixth predictor is chosen. If the value of idelta is less then 16 it is set
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to 16.
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*/
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unsigned int best_bpred = 0;
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unsigned int best_idelta = 0;
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/* Microsoft uses an IDELTA_COUNT (number of sample pairs used to choose
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best predictor) value of 3. The best possible results would be obtained
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by using all the samples to choose the predictor. */
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unsigned int idelta_count = min ( MSADPCM_IDELTA_COUNT, vecsAudio.Size() - 1 );
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for ( unsigned int bpred = 0; bpred < MSADPCM_ADAPT_COEFF_COUNT; bpred++ )
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{
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unsigned int idelta_sum = 0 ;
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for ( unsigned int k = 2 ; k < 2 + idelta_count ; k++ )
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{
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idelta_sum += abs ( vecsAudio[k] -
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( ( vecsAudio[k - 1] * ms_AdaptCoeff1[bpred] +
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vecsAudio[k - 2] * ms_AdaptCoeff2[bpred] ) >> 8 ) );
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}
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idelta_sum /= ( 4 * idelta_count );
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if ( bpred == 0 || idelta_sum < best_idelta )
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{
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best_bpred = bpred;
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best_idelta = idelta_sum;
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}
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if ( !idelta_sum )
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{
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best_bpred = bpred;
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best_idelta = 16;
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break;
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}
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}
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if ( best_idelta < 16 )
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{
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best_idelta = 16;
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}
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block_pred = best_bpred;
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idelta = best_idelta;
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return;
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}
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@ -31,18 +31,20 @@
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/* Definitions ****************************************************************/
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// tables
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// tables IMA-ADPCM
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#define IMA_INDX_ADJUST_TAB_LEN 16
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static int ima_indx_adjust[IMA_INDX_ADJUST_TAB_LEN] =
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{ -1, -1, -1, -1, /* +0 - +3, decrease the step size */
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2, 4, 6, 8, /* +4 - +7, increase the step size */
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-1, -1, -1, -1, /* -0 - -3, decrease the step size */
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2, 4, 6, 8, /* -4 - -7, increase the step size */
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{
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-1, -1, -1, -1, /* +0 - +3, decrease the step size */
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2, 4, 6, 8, /* +4 - +7, increase the step size */
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-1, -1, -1, -1, /* -0 - -3, decrease the step size */
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2, 4, 6, 8, /* -4 - -7, increase the step size */
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};
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#define IMA_STEP_SIZE_TAB_LEN 89
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static int ima_step_size[IMA_STEP_SIZE_TAB_LEN] =
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{ 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
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{
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7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
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50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230,
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253, 279, 307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
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1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327,
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@ -51,6 +53,26 @@ static int ima_step_size[IMA_STEP_SIZE_TAB_LEN] =
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32767
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};
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// tables MS-ADPCM
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#define MSADPCM_IDELTA_COUNT 20
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#define MSADPCM_ADAPT_COEFF_COUNT 7
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static int ms_AdaptCoeff1[MSADPCM_ADAPT_COEFF_COUNT] =
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{
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256, 512, 0, 192, 240, 460, 392
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};
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static int ms_AdaptCoeff2[MSADPCM_ADAPT_COEFF_COUNT] =
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{
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0, -256, 0, 64, 0, -208, -232
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};
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static int ms_AdaptationTable[] =
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{
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230, 230, 230, 230, 307, 409, 512, 614,
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768, 614, 512, 409, 307, 230, 230, 230
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};
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/* Classes ********************************************************************/
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/* IMA-ADPCM ---------------------------------------------------------------- */
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@ -87,11 +109,32 @@ protected:
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};
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/* MS-ADPCM ----------------------------------------------------------------- */
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class CMsAdpcm
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{
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public:
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CMsAdpcm() {}
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virtual ~CMsAdpcm() {}
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int Init ( const int iNewAudioLen );
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CVector<unsigned char> Encode ( const CVector<short>& vecsAudio );
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CVector<short> Decode ( const CVector<unsigned char>& vecbyAdpcm );
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protected:
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int iAudSize;
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int iAdpcmSize;
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void ChoosePredictor ( const CVector<short>& vecsAudio,
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int& block_pred,
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int& idelta );
|
||||
};
|
||||
|
||||
|
||||
/* Audio compression class -------------------------------------------------- */
|
||||
class CAudioCompression
|
||||
{
|
||||
public:
|
||||
enum EAudComprType { CT_NONE, CT_IMAADPCM };
|
||||
enum EAudComprType { CT_NONE, CT_IMAADPCM, CT_MSADPCM };
|
||||
|
||||
CAudioCompression() {}
|
||||
virtual ~CAudioCompression() {}
|
||||
|
|
@ -104,8 +147,8 @@ public:
|
|||
protected:
|
||||
EAudComprType eAudComprType;
|
||||
CImaAdpcm ImaAdpcm;
|
||||
CMsAdpcm MsAdpcm;
|
||||
int iCodeSize;
|
||||
};
|
||||
|
||||
|
||||
#endif /* !defined ( AUDIOCOMPR_H_OIHGE76GEKJH3249_GEG98EG3_43441912__INCLUDED_ ) */
|
||||
|
|
|
|||
|
|
@ -300,7 +300,7 @@ CAboutDlg::CAboutDlg ( QWidget* parent ) : QDialog ( parent )
|
|||
"<li>Qt cross-platform application framework: <i>http://trolltech.com</li>"
|
||||
"<li>Audio reverberation code: by Perry R. Cook and Gary P. Scavone, "
|
||||
"1995 - 2004 (taken from \"The Synthesis ToolKit in C++ (STK)\")</li>"
|
||||
"<li>IMA-ADPCM: by Erik de Castro Lopo</li>"
|
||||
"<li>ADPCM coders by Erik de Castro Lopo</li>"
|
||||
"<li>Parts from Dream DRM Receiver by Volker Fischer and Alexander "
|
||||
"Kurpiers: <i>http://drm.sf.net</li>"
|
||||
"</ul>"
|
||||
|
|
|
|||
Loading…
Reference in a new issue