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improved RMS calc

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This commit is contained in:
Christian R. Helmrich
2020-03-22 01:00:20 +01:00
parent 27c0818160
commit 7185ac995f
4 changed files with 101 additions and 27 deletions
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54
src/lib/specAnalysis.cpp
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@ -1,5 +1,5 @@
/* specAnalysis.cpp - source file for class providing spectral analysis of MCLT signals
* written by C. R. Helmrich, last modified in 2019 - see License.htm for legal notices
* written by C. R. Helmrich, last modified in 2020 - see License.htm for legal notices
*
* The copyright in this software is being made available under a Modified BSD-Style License
* and comes with ABSOLUTELY NO WARRANTY. This software may be subject to other third-
@ -63,7 +63,7 @@ unsigned SpecAnalyzer::getMeanAbsValues (const int32_t* const mdctSignal, const
const unsigned channelIndex, const uint16_t* const bandStartOffsets, const unsigned nBands,
uint32_t* const meanBandValues)
{
if ((mdctSignal == nullptr) || (bandStartOffsets == nullptr) || (meanBandValues == nullptr) || (channelIndex >= USAC_MAX_NUM_CHANNELS) ||
if ((mdctSignal == nullptr) || (bandStartOffsets == nullptr) || (meanBandValues == nullptr) || (channelIndex > USAC_MAX_NUM_CHANNELS) ||
(nSamplesInFrame > 2048) || (nSamplesInFrame < 2) || (nBands > nSamplesInFrame))
{
return 1; // invalid arguments error
@ -77,7 +77,8 @@ unsigned SpecAnalyzer::getMeanAbsValues (const int32_t* const mdctSignal, const
const unsigned bandWidth = __min (nSamplesInFrame, bandStartOffsets[b + 1]) - bandOffset;
const unsigned anaBandIdx = bandOffset >> SA_BW_SHIFT;
if ((anaBandIdx < m_numAnaBands[channelIndex]) && (bandOffset == (anaBandIdx << SA_BW_SHIFT)) && ((bandWidth & (SA_BW - 1)) == 0))
if ((channelIndex < USAC_MAX_NUM_CHANNELS) && (anaBandIdx < m_numAnaBands[channelIndex]) &&
(bandOffset == (anaBandIdx << SA_BW_SHIFT)) && ((bandWidth & (SA_BW - 1)) == 0))
{
const uint32_t* const anaAbsVal = &m_meanAbsValue[channelIndex][anaBandIdx];
@ -94,13 +95,14 @@ unsigned SpecAnalyzer::getMeanAbsValues (const int32_t* const mdctSignal, const
{
#if SA_EXACT_COMPLEX_ABS
const double complexSqr = (double) bMdct[s] * (double) bMdct[s] + (double) bMdst[s] * (double) bMdst[s];
const unsigned absSample = unsigned (sqrt (complexSqr) + 0.5);
sumAbsVal += uint64_t (sqrt (complexSqr) + 0.5);
#else
const unsigned absReal = abs (bMdct[s]); // Richard Lyons, 1997; en.wikipedia.org/
const unsigned absImag = abs (bMdst[s]); // wiki/Alpha_max_plus_beta_min_algorithm
const unsigned absSample = (absReal > absImag ? absReal + ((absImag * 3) >> 3) : absImag + ((absReal * 3) >> 3));
const uint32_t absReal = abs (bMdct[s]); // Richard Lyons, 1997; en.wikipedia.org/
const uint32_t absImag = abs (bMdst[s]); // wiki/Alpha_max_plus_beta_min_algorithm
sumAbsVal += (absReal > absImag ? absReal + ((absImag * 3) >> 3) : absImag + ((absReal * 3) >> 3));
#endif
sumAbsVal += absSample;
}
// average spectral sample magnitude across current band
meanBandValues[b] = uint32_t ((sumAbsVal + (bandWidth >> 1)) / bandWidth);
@ -114,14 +116,34 @@ unsigned SpecAnalyzer::getMeanAbsValues (const int32_t* const mdctSignal, const
const unsigned bandOffset = __min (nSamplesInFrame, bandStartOffsets[b]);
const unsigned bandWidth = __min (nSamplesInFrame, bandStartOffsets[b + 1]) - bandOffset;
const int32_t* const bMdct = &mdctSignal[bandOffset];
#if SA_IMPROVED_REAL_ABS
uint64_t sumAbsVal = (bandStartOffsets[b + 1] == nSamplesInFrame ? abs (bMdct[bandWidth - 1]) : 0);
for (int s = bandWidth - (bandStartOffsets[b + 1] == nSamplesInFrame ? 2 : 1); s >= 0; s--)
{
// based on S. Merdjani, L. Daudet, "Estimation of Frequency from MDCT-Encoded Files,"
// DAFx-03, 2003, http://www.eecs.qmul.ac.uk/legacy/dafx03/proceedings/pdfs/dafx01.pdf
const uint32_t absReal = abs (bMdct[s]); // Richard Lyons, 1997; see also code above
const uint32_t absEstIm = abs (bMdct[s + 1] - bMdct[s - 1]) >> 1; // s - 1 may be -1!
sumAbsVal += (absReal > absEstIm ? absReal + ((absEstIm * 3) >> 3) : absEstIm + ((absReal * 3) >> 3));
}
if ((b == 0) && (bandWidth > 0)) // correct estimate at DC
{
const uint32_t absReal = abs (bMdct[0]); // Richard Lyons, 1997; see also code above
const uint32_t absEstIm = abs (bMdct[1] - bMdct[-1]) >> 1; // if s - 1 was -1 earlier
sumAbsVal -= (absReal > absEstIm ? absReal + ((absEstIm * 3) >> 3) : absEstIm + ((absReal * 3) >> 3));
sumAbsVal += absReal;
}
#else
uint64_t sumAbsVal = 0;
for (int s = bandWidth - 1; s >= 0; s--)
{
const unsigned absSample = abs (bMdct[s]);
sumAbsVal += absSample;
sumAbsVal += abs (bMdct[s]);
}
#endif
// average spectral sample magnitude across frequency band
meanBandValues[b] = uint32_t ((sumAbsVal + (bandWidth >> 1)) / bandWidth);
} // for b
@ -262,11 +284,11 @@ unsigned SpecAnalyzer::spectralAnalysis (const int32_t* const mdctSignals[USAC_M
// sum absolute values of complex signal, derive L1 norm, peak value, and peak index
#if SA_EXACT_COMPLEX_ABS
const double complexSqr = (double) bMdct[s] * (double) bMdct[s] + (double) bMdst[s] * (double) bMdst[s];
const unsigned absSample = unsigned (sqrt (complexSqr) + 0.5);
const uint32_t absSample = uint32_t (sqrt (complexSqr) + 0.5);
#else
const unsigned absReal = abs (bMdct[s]); // Richard Lyons, 1997; en.wikipedia.org/
const unsigned absImag = abs (bMdst[s]); // wiki/Alpha_max_plus_beta_min_algorithm
const unsigned absSample = (absReal > absImag ? absReal + ((absImag * 3) >> 3) : absImag + ((absReal * 3) >> 3));
const uint32_t absReal = abs (bMdct[s]); // Richard Lyons, 1997; en.wikipedia.org/
const uint32_t absImag = abs (bMdst[s]); // wiki/Alpha_max_plus_beta_min_algorithm
const uint32_t absSample = (absReal > absImag ? absReal + ((absImag * 3) >> 3) : absImag + ((absReal * 3) >> 3));
#endif
sumAbsVal += absSample;
if (offs + s > 0) // exclude DC from max/min
@ -288,7 +310,7 @@ unsigned SpecAnalyzer::spectralAnalysis (const int32_t* const mdctSignals[USAC_M
for (int s = SA_BW - 1; s >= 0; s--)
{
// obtain absolute values of real signal, derive L1 norm, peak value, and peak index
const unsigned absSample = abs (bMdct[s]);
const uint32_t absSample = abs (bMdct[s]);
sumAbsVal += absSample;
if (offs + s > 0) // exclude DC from max/min