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/******************************** MPEG Audio Encoder **************************
(C) Copyright Fraunhofer IIS (1997)
All Rights Reserved
Please be advised that this software and/or program delivery is
Confidential Information of Fraunhofer and subject to and covered by the
Fraunhofer IIS Software Evaluation Agreement
between Google Inc. and Fraunhofer
effective and in full force since March 1, 2012.
You may use this software and/or program only under the terms and
conditions described in the above mentioned Fraunhofer IIS Software
Evaluation Agreement. Any other and/or further use requires a separate agreement.
This software and/or program is protected by copyright law and international
treaties. Any reproduction or distribution of this software and/or program,
or any portion of it, may result in severe civil and criminal penalties, and
will be prosecuted to the maximum extent possible under law.
$Id$
Initial author: M. Werner
contents/description: Chaos measure calculation
******************************************************************************/
#include "chaosmeasure.h"
/*****************************************************************************
functionname: FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast
description: Eberlein method of chaos measure calculation by high-pass
filtering amplitude spectrum
A special case of FDKaacEnc_CalculateChaosMeasureTonalGeneric --
highly optimized
*****************************************************************************/
static void
FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast( FIXP_DBL *RESTRICT paMDCTDataNM0,
INT numberOfLines,
FIXP_DBL *RESTRICT chaosMeasure )
{
INT i, j;
/* calculate chaos measure by "peak filter" */
for (i=0; i<2; i++) {
/* make even and odd pass through data */
FIXP_DBL left,center; /* left, center tap of filter */
left = (FIXP_DBL)((LONG)paMDCTDataNM0[i]^((LONG)paMDCTDataNM0[i]>>(DFRACT_BITS-1)));
center = (FIXP_DBL)((LONG)paMDCTDataNM0[i+2]^((LONG)paMDCTDataNM0[i+2]>>(DFRACT_BITS-1)));
for (j = i+2; j < numberOfLines - 2; j+=2) {
FIXP_DBL right = (FIXP_DBL)((LONG)paMDCTDataNM0[j+2]^((LONG)paMDCTDataNM0[j+2]>>(DFRACT_BITS-1)));
FIXP_DBL tmp = (left>>1)+(right>>1);
if (tmp < center ) {
INT leadingBits = CntLeadingZeros(center)-1;
tmp = schur_div(tmp<<leadingBits, center<<leadingBits, 8);
chaosMeasure[j] = fMult(tmp,tmp);
}
else {
chaosMeasure[j] = (FIXP_DBL)MAXVAL_DBL;
}
left = center;
center = right;
}
}
/* provide chaos measure for first few lines */
chaosMeasure[0] = chaosMeasure[2];
chaosMeasure[1] = chaosMeasure[2];
/* provide chaos measure for last few lines */
for (i = (numberOfLines-3); i < numberOfLines; i++)
chaosMeasure[i] = FL2FXCONST_DBL(0.5);
}
/*****************************************************************************
functionname: FDKaacEnc_CalculateChaosMeasure
description: calculates a chaosmeasure for every line, different methods
are available. 0 means tonal, 1 means noiselike
returns:
input: MDCT data, number of lines
output: chaosMeasure
*****************************************************************************/
void
FDKaacEnc_CalculateChaosMeasure( FIXP_DBL *paMDCTDataNM0,
INT numberOfLines,
FIXP_DBL *chaosMeasure )
{
FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast( paMDCTDataNM0,
numberOfLines,
chaosMeasure );
}
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