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/**
* Smarc
*
* Copyright (c) 2009-2011 Institut Tlcom - Tlcom Paristech
* Tlcom ParisTech / dept. TSI
*
* Authors : Benoit Mathieu, Jacques Prado
*
* This file is part of Smarc.
*
* Smarc is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Smarc is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef SMARC_H_
#define SMARC_H_
#ifdef __cplusplus
extern "C" {
#endif
/**
* PFilter represent a multi-stage polyphase filter
*/
struct PFilter;
/**
* Build a PFilter with given parameter. Given pointer must be free by calling destroy_pfilter function
* - fsin (IN) : frequency samplerate of input signal
* - fsout (IN) : desired frequency samplerate for output signal
* - bandwidth (IN) : bandwidth to keep, real in 0..1. For example, 0.95 means that 95% of maximum
* possible bandwidth is kept. Too high value may results in impossible filter to design.
* - rp (IN) : Passband ripple factor, in dB.
* - rs (IN) : Stopband ripple factor, in dB.
* - tol (IN) : samplerate conversion error tolerance. Usual value for tol is 0.000001. Usual frequencies conversion
* has exact samplerate conversion, but for unusual frequencies, in particular when fsin or fsout
* are large prime numbers, the user should accept a tolerance otherwise the filter may
* be impossible to design.
* - userratios (IN) : ratios to use to build multistage samplerate converter, in following format :
* 'L1/M2 L2/M2 ...'. This parameter is optional.
* - searchfastconversion (IN) : if 1 try to search fastest conversion stages. This may fail.
* if 0 use safe default conversion stages.
*/
struct PFilter* smarc_init_pfilter(int fsin, const int fsout,
double bandwidth, double rp, double rs,
double tol, const char* userratios, int searchfastconversion);
/**
* release PFilter
*/
void smarc_destroy_pfilter(struct PFilter*);
/**
* returns input frequency samplerate for PFilter
*/
int smarc_get_fs_in(struct PFilter*);
/**
* return output frequency samplerate for PFilter
*/
int smarc_get_fs_out(struct PFilter*);
/**
* return a recommended output buffer size to safely resample
* input signal chunks of length inSize with filter pfilt
*/
int smarc_get_output_buffer_size(struct PFilter* pfilt,int inSize);
/**
* print PFilter informations to standard output
*/
void smarc_print_pfilter(struct PFilter*);
/**
* PState represent a filter state. A PFilter may be used to filter several channels, each channels having its own PState.
*/
struct PState;
/**
* Create a PState for a given PFilter. Returned pointer must be freed by destroy_pstate()
*/
struct PState* smarc_init_pstate(struct PFilter*);
/**
* Free PState
*/
void smarc_destroy_pstate(struct PState*);
/**
* Reset PState so that it can be used to process another signal.
*/
void smarc_reset_pstate(struct PState*, struct PFilter*);
/**
* Resample a chunk of signal.
* - pfilter [IN]: PFilter used to resample
* - pstate [IN/OUT]: current state of resampler
* - signal [IN]: array holding signal to resample
* - signalLength [IN]: length of signal to resample
* - output [OUT]: buffer where to write resampled signal
* - outputLength [IN]: size of output buffer.
* Returns the number of output samples written.
*/
int smarc_resample(struct PFilter* pfilter, struct PState* pstate,
const double* signal,
int signalLength,
double* output,
int outputLength);
/**
* Flush all sample in state considering there will be no more input signal.
* This function must be called only once.
* - pfilter [IN]: PFilter used to resample
* - pstate [IN/OUT]: current state of resampler
* - output [OUT]: buffer where to write resampled signal
* - outputLength [IN]: size of output buffer.
* Returns the number of output samples written.
*/
int smarc_resample_flush(struct PFilter*, struct PState*,
double* output,
int outputLength);
#ifdef __cplusplus
}
#endif
#endif /* SMARC_H_ */
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