/*
?*?libmfcc.c?-?Code?implementation?for?libMFCC
?*?Copyright?（c）?2010?Jeremy?Sawruk
?*
?*?This?code?is?released?under?the?MIT?License.?
?*?For?conditions?of?distribution?and?use?see?the?license?in?LICENSE
?*/

#include?
#include?“libmfcc.h“

/*?
?*?Computes?the?specified?（mth）?MFCC
?*
?*?spectralData?-?array?of?doubles?containing?the?results?of?FFT?computation.?This?data?is?already?assumed?to?be?purely?real
?*?samplingRate?-?the?rate?that?the?original?time-series?data?was?sampled?at?（i.e?44100）
?*?NumFilters?-?the?number?of?filters?to?use?in?the?computation.?Recommended?value?=?48
?*?binSize?-?the?size?of?the?spectralData?array?usually?a?power?of?2
?*?m?-?The?mth?MFCC?coefficient?to?compute
?*
?*/
double?GetCoefficient（double*?spectralData?unsigned?int?samplingRate?unsigned?int?NumFilters?unsigned?int?binSize?unsigned?int?m）
{
	double?result?=?0.0f;
	double?outerSum?=?0.0f;
	double?innerSum?=?0.0f;
	unsigned?int?k?l;

	//?0?<=?m?	if（m?>=?NumFilters）
	{
		//?This?represents?an?error?condition?-?the?specified?coefficient?is?greater?than?or?equal?to?the?number?of?filters.?The?behavior?in?this?case?is?undefined.
		return?0.0f;
	}

	result?=?NormalizationFactor（NumFilters?m）;

	
	for（l?=?1;?l?<=?NumFilters;?l++）
	{
		//?Compute?inner?sum
		innerSum?=?0.0f;
		for（k?=?0;?k?		{
			innerSum?+=?fabs（spectralData[k]?*?GetFilterParameter（samplingRate?binSize?k?l））;
		}

		if（innerSum?>?0.0f）
		{
			innerSum?=?log（innerSum）;?//?The?log?of?0?is?undefined?so?don‘t?use?it
		}

		innerSum?=?innerSum?*?cos（（（m?*?PI）?/?NumFilters）?*?（l?-?0.5f））;

		outerSum?+=?innerSum;
	}

	result?*=?outerSum;

	return?result;
}

/*?
?*?Computes?the?Normalization?Factor?（Equation?6）
?*?Used?for?internal?computation?only?-?not?to?be?called?directly
?*/
double?NormalizationFactor（int?NumFilters?int?m）
{
	double?normalizationFactor?=?0.0f;

	if（m?==?0）
	{
		normalizationFactor?=?sqrt（1.0f?/?NumFilters）;
	}
	else?
	{
		normalizationFactor?=?sqrt（2.0f?/?NumFilters）;
	}
	
	return?normalizationFactor;
}

/*?
?*?Compute?the?filter?parameter?for?the?specified?frequency?and?filter?bands?（Eq.?2）
?*?Used?for?internal?computation?only?-?not?the?be?called?directly
?*/
double?GetFilterParameter（unsigned?int?samplingRate?unsigned?int?binSize?unsigned?int?frequencyBand?unsigned?int?filterBand）
{
	double?filterParameter?=?0.0f;

	double?boundary?=?（frequencyBand?*?samplingRate）?/?binSize;		//?k?*?Fs?/?N
	double?prevCenterFrequency?=?GetCenterFrequency（filterBand?-?1）;		//?fc（l?-?1）?etc.
	double?thisCenterFrequency?=?GetCenterFrequency（filterBand）;
	double?nextCenterFrequency?=?GetCenterFrequency（filterBand?+?1）;

	if（boundary?>=?0?&&?boundary?	{
		filterParameter?=?0.0f;
	}
	else?if（boundary?>=?prevCenterFrequency?&&?boundary?	{
		filterParameter?=?（boundary?-?prevCenterFrequency）?/?（thisCenterFrequency?-

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2016-03-18?22:14??libmfcc\
?????文件??????214692??2016-03-18?22:14??libmfcc\Sturm2010b.pdf
?????文件????????1240??2016-03-18?22:14??libmfcc\libmfcc.h
?????文件?????????283??2016-03-18?22:14??libmfcc\TODO
?????目錄???????????0??2016-03-18?22:14??libmfcc\libmfcc_example\
?????文件????????1376??2016-03-18?22:14??libmfcc\libmfcc_example\example.c
?????文件???????82062??2016-03-18?22:14??libmfcc\libmfcc_example\sample.dat
?????文件????????4705??2016-03-18?22:14??libmfcc\libmfcc.c
?????目錄???????????0??2016-03-18?22:14??libmfcc\.hg\
?????文件???????????0??2016-03-18?22:14??libmfcc\.hg\undo.dirstate
?????目錄???????????0??2016-03-18?22:14??libmfcc\.hg\cache\
?????文件??????????44??2016-03-18?22:14??libmfcc\.hg\cache\tags
?????文件??????????92??2016-03-18?22:14??libmfcc\.hg\cache\branchheads
?????文件?????????276??2016-03-18?22:14??libmfcc\.hg\dirstate
?????文件???????????8??2016-03-18?22:14??libmfcc\.hg\branch
?????文件??????????42??2016-03-18?22:14??libmfcc\.hg\undo.desc
?????目錄???????????0??2016-03-18?22:14??libmfcc\.hg\store\
?????文件?????????186??2016-03-18?22:14??libmfcc\.hg\store\fncache
?????目錄???????????0??2016-03-18?22:14??libmfcc\.hg\store\data\
?????文件??????????64??2016-03-18?22:14??libmfcc\.hg\store\data\_sturm2010b.pdf.i
?????目錄???????????0??2016-03-18?22:14??libmfcc\.hg\store\data\libmfcc__example\
?????文件???????32456??2016-03-18?22:14??libmfcc\.hg\store\data\libmfcc__example\sample.dat.i
?????文件?????????770??2016-03-18?22:14??libmfcc\.hg\store\data\libmfcc__example\example.c.i
?????文件?????????501??2016-03-18?22:14??libmfcc\.hg\store\data\_r_e_a_d_m_e.i
?????文件??????197952??2016-03-18?22:14??libmfcc\.hg\store\data\_sturm2010b.pdf.d
?????文件?????????570??2016-03-18?22:14??libmfcc\.hg\store\data\libmfcc.h.i
?????文件?????????714??2016-03-18?22:14??libmfcc\.hg\store\data\_l_i_c_e_n_s_e.i
?????文件?????????262??2016-03-18?22:14??libmfcc\.hg\store\data\_t_o_d_o.i
?????文件????????1512??2016-03-18?22:14??libmfcc\.hg\store\data\libmfcc.c.i
?????文件???????????0??2016-03-18?22:14??libmfcc\.hg\store\undo.phaseroots
?????文件???????????0??2016-03-18?22:14??libmfcc\.hg\store\phaseroots
............此處省略10個文件信息