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87 lines
1.9 KiB
C
87 lines
1.9 KiB
C
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/* $Header: /cvs/root/winamp/vlb/tns.h,v 1.1 2009/04/28 20:21:11 audiodsp Exp $ */
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/***************************************************************************\
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*
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* Copyright 2000-2002 Dolby Laboratories, Inc. All Rights
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* Reserved. Do not copy. Do not distribute.
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* Confidential information.
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*
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* (C) copyright Fraunhofer - IIS (1998)
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* All Rights Reserved
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*
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* filename: tns.h
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* project : MPEG-2 AAC Decoder
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* contents/description: temporal noise shaping
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*
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\***************************************************************************/
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#ifndef __TNS_H__
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#define __TNS_H__
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#include "bitsequence.h"
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class CChannelInfo ;
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class CBlock ;
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/** Temporal Noise Shaping.
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This class represents the temporal noise shaping tool for decoding and
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applying tns filter data to the spectral coefficients of the current block.
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TNS is a profile-dependent tool and the CTns implementation follows the
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Read()/Apply() convention used for all tools.
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*/
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class CTns
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{
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public :
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CTns () ;
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~CTns () ;
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void Read (const CChannelInfo &info, CDolbyBitStream &bs) ;
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void Apply (const CChannelInfo &info, CBlock &spectrum) ;
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enum
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{
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MaximumWindows = 8,
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MaximumBands = 49,
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MaximumOrder = 31,
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MaximumFilters = 3
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} ;
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protected :
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CVLBBitSequence m_TnsDataPresent ;
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class CFilter
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{
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public :
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int m_StartBand ;
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int m_StopBand ;
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int m_Direction ;
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int m_Resolution ;
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int m_Order ;
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int m_Coeff [MaximumOrder] ;
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} ;
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int m_NumberOfFilters [MaximumWindows] ;
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CFilter m_Filter [MaximumWindows][MaximumFilters] ;
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int Minimum (int a, int b, int c)
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{
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int t = (a < b ) ? a : b ;
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return (t < c) ? t : c ;
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}
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void DecodeCoefficients (CFilter &filter, float *a) ;
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void Filter (float *spec, int size, int inc, float *lpc, int order) ;
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} ;
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#endif
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