gainquant.h File Reference

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Functions
float	gaindequant (int index, float maxIn, int cblen)
float	gainquant (float in, float maxIn, int cblen, int *index)

Function Documentation

gaindequant()

float gaindequant	(	int	index,
		float	maxIn,
		int	cblen
	)

Definition at line 83 of file gainquant.c.

References gain_sq3Tbl, gain_sq4Tbl, and gain_sq5Tbl.

Referenced by iCBConstruct().

 {
 float scale;

 /* obtain correct scale factor */

 scale=(float)fabs(maxIn);

 if (scale<0.1) {
 scale=(float)0.1;
 }

 /* select the quantization table and return the decoded value */

 if (cblen==8) {
 return scale*gain_sq3Tbl[index];
 } else if (cblen==16) {
 return scale*gain_sq4Tbl[index];
 }
 else if (cblen==32) {
 return scale*gain_sq5Tbl[index];
 }

 return 0.0;
 }

gainquant()

float gainquant	(	float	in,
		float	maxIn,
		int	cblen,
		int *	index
	)

Definition at line 27 of file gainquant.c.

References gain_sq3Tbl, gain_sq4Tbl, and gain_sq5Tbl.

Referenced by iCBSearch().

 {
 int i, tindex;
 float minmeasure,measure, *cb, scale;

 /* ensure a lower bound on the scaling factor */

 scale=maxIn;

 if (scale<0.1) {
 scale=(float)0.1;
 }

 /* select the quantization table */

 if (cblen == 8) {
 cb = gain_sq3Tbl;
 } else if (cblen == 16) {
 cb = gain_sq4Tbl;
 } else {
 cb = gain_sq5Tbl;
 }

 /* select the best index in the quantization table */

 minmeasure=10000000.0;
 tindex=0;
 for (i=0; i<cblen; i++) {





 measure=(in-scale*cb[i])*(in-scale*cb[i]);

 if (measure<minmeasure) {
 tindex=i;
 minmeasure=measure;
 }
 }
 *index=tindex;

 /* return the quantized value */

 return scale*cb[tindex];
 }