67 lines
3.9 KiB
C
67 lines
3.9 KiB
C
/*
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* iLBC - a library for the iLBC codec
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*
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* filter.h - The iLBC low bit rate speech codec.
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*
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* Adapted by Steve Underwood <steveu@coppice.org> from the reference
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* iLBC code supplied in RFC3951.
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*
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* Original code Copyright (C) The Internet Society (2004).
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* All changes to produce this version Copyright (C) 2008 by Steve Underwood
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* All Rights Reserved.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*
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* $Id: filter.h,v 1.2 2008/03/06 12:27:38 steveu Exp $
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*/
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#ifndef __iLBC_FILTER_H
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#define __iLBC_FILTER_H
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void AllPoleFilter(float *InOut, /* (i/o) on entrance InOut[-orderCoef] to
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InOut[-1] contain the state of the
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filter (delayed samples). InOut[0] to
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InOut[lengthInOut-1] contain the filter
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input, on en exit InOut[-orderCoef] to
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InOut[-1] is unchanged and InOut[0] to
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InOut[lengthInOut-1] contain filtered
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samples */
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const float *Coef, /* (i) filter coefficients, Coef[0] is assumed to be 1.0 */
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int lengthInOut, /* (i) number of input/output samples */
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int orderCoef); /* (i) number of filter coefficients */
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void AllZeroFilter(float *In, /* (i) In[0] to In[lengthInOut-1] contain
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filter input samples */
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const float *Coef, /* (i) filter coefficients (Coef[0] is assumed to be 1.0) */
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int lengthInOut, /* (i) number of input/output samples */
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int orderCoef, /* (i) number of filter coefficients */
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float *Out); /* (i/o) on entrance Out[-orderCoef] to Out[-1]
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contain the filter state, on exit Out[0]
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to Out[lengthInOut-1] contain filtered
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samples */
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void ZeroPoleFilter(float *In, /* (i) In[0] to In[lengthInOut-1] contain filter
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input samples In[-orderCoef] to In[-1]
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contain state of all-zero section */
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const float *ZeroCoef, /* (i) filter coefficients for all-zero
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section (ZeroCoef[0] is assumed to
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be 1.0) */
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const float *PoleCoef, /* (i) filter coefficients for all-pole section
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(ZeroCoef[0] is assumed to be 1.0) */
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int lengthInOut, /* (i) number of input/output samples */
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int orderCoef, /* (i) number of filter coefficients */
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float *Out); /* (i/o) on entrance Out[-orderCoef] to Out[-1]
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contain state of all-pole section. On
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exit Out[0] to Out[lengthInOut-1]
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contain filtered samples */
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void DownSample(const float *In, /* (i) input samples */
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const float *Coef, /* (i) filter coefficients */
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int lengthIn, /* (i) number of input samples */
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float *state, /* (i) filter state */
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float *Out); /* (o) downsampled output */
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#endif
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