/* * Copyright (c) 2008 MUSIC TECHNOLOGY GROUP (MTG) * UNIVERSITAT POMPEU FABRA * * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ /*! \file harmDetection.c * \brief Detection of a given harmonic */ #include "sms.h" #define N_FUND_HARM 6 /*!< number of harmonics to use for fundamental detection */ #define N_HARM_PEAKS 4 /*!< number of peaks to check as possible ref harmonics */ #define FREQ_DEV_THRES .07 /*!< threshold for deviation from perfect harmonics */ #define MAG_PERC_THRES .6 /*!< threshold for magnitude of harmonics with respect to the total magnitude */ #define HARM_RATIO_THRES .8 /*!< threshold for percentage of harmonics found */ /*! \brief get closest peak to a given harmonic of the possible fundamental * * \param iPeakCandidate peak number of possible fundamental * \param nHarm number of harmonic * \param pSpectralPeaks pointer to all the peaks * \param pICurrentPeak pointer to the last peak taken * \param iRefHarmonic reference harmonic number * \return the number of the closest peak or -1 if not found */ static int GetClosestPeak(int iPeakCandidate, int nHarm, SMS_Peak *pSpectralPeaks, int *pICurrentPeak, int iRefHarmonic, int maxPeaks) { int iBestPeak = *pICurrentPeak + 1; int iNextPeak = iBestPeak + 1; if((iBestPeak >= maxPeaks) || (iNextPeak >= maxPeaks)) return -1; sfloat fBestPeakFreq = pSpectralPeaks[iBestPeak].fFreq, fHarmFreq = (1 + nHarm) * pSpectralPeaks[iPeakCandidate].fFreq / iRefHarmonic, fMinDistance = fabs(fHarmFreq - fBestPeakFreq), fMaxPeakDev = .5 * fHarmFreq / (nHarm + 1), fDistance = 0.0; fDistance = fabs(fHarmFreq - pSpectralPeaks[iNextPeak].fFreq); while((fDistance < fMinDistance) && (iNextPeak < maxPeaks - 1)) { iBestPeak = iNextPeak; fMinDistance = fDistance; iNextPeak++; fDistance = fabs(fHarmFreq - pSpectralPeaks[iNextPeak].fFreq); } /* make sure the chosen peak is good */ fBestPeakFreq = pSpectralPeaks[iBestPeak].fFreq; /* if best peak is not in the range */ if(fabs(fBestPeakFreq - fHarmFreq) > fMaxPeakDev) return -1; *pICurrentPeak = iBestPeak; return iBestPeak; } /*! \brief checks if peak is substantial * * check if peak is larger enough to be considered a fundamental * without any further testing or too small to be considered * * \param fRefHarmMag magnitude of possible fundamental * \param pSpectralPeaks all the peaks * \param nCand number of existing candidates * \param fRefHarmMagDiffFromMax value to judge the peak based on the difference of its magnitude compared to the reference * \return 1 if big peak, -1 if too small , otherwise return 0 */ static int ComparePeak(sfloat fRefHarmMag, SMS_Peak *pSpectralPeaks, int nCand, sfloat fRefHarmMagDiffFromMax, int maxPeaks) { int iPeak; sfloat fMag = 0; /* if peak is very large take it as possible fundamental */ if(nCand == 0 && fRefHarmMag > 80.) return 1; /* compare the peak with the first N_FUND_HARM peaks */ /* if too small forget it */ for(iPeak = 0; (iPeak < N_FUND_HARM) && (iPeak < maxPeaks); iPeak++) { if(pSpectralPeaks[iPeak].fMag > 0 && fRefHarmMag - pSpectralPeaks[iPeak].fMag < - fRefHarmMagDiffFromMax) return -1; } /* if it is much bigger than rest take it */ for(iPeak = 0; (iPeak < N_FUND_HARM) && (iPeak < maxPeaks); iPeak++) { fMag = pSpectralPeaks[iPeak].fMag; if(fMag <= 0 || ((fMag != fRefHarmMag) && (nCand > 0) && (fRefHarmMag - fMag < 30.0)) || ((nCand == 0) && (fRefHarmMag - fMag < 15.0))) return 0; } return 1; } /*! \brief check if the current peak is a harmonic of one of the candidates * * \param fFundFreq frequency of peak to be tested * \param pCHarmonic all candidates accepted * \param nCand location of las candidate * \return 1 if it is a harmonic, 0 if it is not */ static int CheckIfHarmonic(sfloat fFundFreq, SMS_HarmCandidate *pCHarmonic, int nCand) { int iPeak; /* go through all the candidates checking if they are fundamentals * of the peak to be considered */ for(iPeak = 0; iPeak < nCand; iPeak++) { if(fabs(floor((double)(fFundFreq / pCHarmonic[iPeak].fFreq) + .5) - (fFundFreq / pCHarmonic[iPeak].fFreq)) <= .1) return 1; } return 0; } /*! \brief consider a peak as a possible candidate and give it a weight value, * * \param iPeak iPeak number to be considered * \param pSpectralPeaks all the peaks * \param pCHarmonic all the candidates * \param nCand candidate number that is to be filled * \param pPeakParams analysis parameters * \param fRefFundamental previous fundamental * \return -1 if not good enough for a candidate, return 0 if reached * the top frequency boundary, return -2 if stop checking because it * found a really good one, return 1 if the peak is a good candidate */ static int GoodCandidate(int iPeak, int maxPeaks, SMS_Peak *pSpectralPeaks, SMS_HarmCandidate *pCHarmonic, int nCand, int soundType, sfloat fRefFundamental, sfloat minRefHarmMag, sfloat refHarmMagDiffFromMax, sfloat refHarmonic) { sfloat fHarmFreq = 0.0, fRefHarmFreq = 0.0, fRefHarmMag = 0.0, fTotalMag = 0.0, fTotalDev = 0.0, fTotalMaxMag = 0.0, fAvgMag = 0.0, fAvgDev = 0.0, fHarmRatio = 0.0; int iHarm = 0, iChosenPeak = 0, iPeakComp = 0, iCurrentPeak = 0, nGoodHarm = 0, i = 0; fRefHarmFreq = fHarmFreq = pSpectralPeaks[iPeak].fFreq; fTotalDev = 0; fRefHarmMag = pSpectralPeaks[iPeak].fMag; fTotalMag = fRefHarmMag; /* check if magnitude is big enough */ /*! \bug sfloat comparison to 0 */ if(((fRefFundamental > 0) && (fRefHarmMag < minRefHarmMag - 10)) || ((fRefFundamental <= 0) && (fRefHarmMag < minRefHarmMag))) return -1; /* check that it is not a harmonic of a previous candidate */ if(nCand > 0 && CheckIfHarmonic(fRefHarmFreq / refHarmonic, pCHarmonic, nCand)) return -1; /* check if it is very big or very small */ iPeakComp = ComparePeak(fRefHarmMag, pSpectralPeaks, nCand, refHarmMagDiffFromMax, maxPeaks); /* too small */ if(iPeakComp == -1) return -1; /* very big */ else if(iPeakComp == 1) { pCHarmonic[nCand].fFreq = fRefHarmFreq; pCHarmonic[nCand].fMag = fRefHarmMag; pCHarmonic[nCand].fMagPerc = 1; pCHarmonic[nCand].fFreqDev = 0; pCHarmonic[nCand].fHarmRatio = 1; return -2; } /* get a weight on the peak by comparing its harmonic series */ /* with the existing peaks */ if(soundType != SMS_SOUND_TYPE_NOTE) { fHarmFreq = fRefHarmFreq; iCurrentPeak = iPeak; nGoodHarm = 0; for(iHarm = refHarmonic; (iHarm < N_FUND_HARM) && (iHarm < maxPeaks); iHarm++) { fHarmFreq += fRefHarmFreq / refHarmonic; iChosenPeak = GetClosestPeak(iPeak, iHarm, pSpectralPeaks, &iCurrentPeak, refHarmonic, maxPeaks); if(iChosenPeak > 0) { fTotalDev += fabs(fHarmFreq - pSpectralPeaks[iChosenPeak].fFreq) / fHarmFreq; fTotalMag += pSpectralPeaks[iChosenPeak].fMag; nGoodHarm++; } } for(i = 0; i <= iCurrentPeak; i++) fTotalMaxMag += pSpectralPeaks[i].fMag; fAvgDev = fTotalDev / (iHarm + 1); fAvgMag = fTotalMag / fTotalMaxMag; fHarmRatio = (sfloat)nGoodHarm / (N_FUND_HARM - 1); if(fRefFundamental > 0) { if(fAvgDev > FREQ_DEV_THRES || fAvgMag < MAG_PERC_THRES - .1 || fHarmRatio < HARM_RATIO_THRES - .1) return -1; } else { if(fAvgDev > FREQ_DEV_THRES || fAvgMag < MAG_PERC_THRES || fHarmRatio < HARM_RATIO_THRES) return -1; } } pCHarmonic[nCand].fFreq = fRefHarmFreq; pCHarmonic[nCand].fMag = fRefHarmMag; pCHarmonic[nCand].fMagPerc = fAvgMag; pCHarmonic[nCand].fFreqDev = fAvgDev; pCHarmonic[nCand].fHarmRatio = fHarmRatio; return 1; } /*! \brief choose the best fundamental out of all the candidates * * \param pCHarmonic array of candidates * \param iRefHarmonic reference harmonic number * \param nGoodPeaks number of candiates * \param fPrevFund reference fundamental * \return the integer number of the best candidate */ static int GetBestCandidate(SMS_HarmCandidate *pCHarmonic, int iRefHarmonic, int nGoodPeaks, sfloat fPrevFund) { int iBestCandidate = 0, iPeak; sfloat fBestFreq, fHarmFreq, fDev; /* if a fundamental existed in previous frame take the closest candidate */ if(fPrevFund > 0) { for(iPeak = 1; iPeak < nGoodPeaks; iPeak++) { if(fabs(fPrevFund - pCHarmonic[iPeak].fFreq / iRefHarmonic) < fabs(fPrevFund - pCHarmonic[iBestCandidate].fFreq / iRefHarmonic)) iBestCandidate = iPeak; } } else { /* try to find the best candidate */ for(iPeak = 1; iPeak < nGoodPeaks; iPeak++) { fBestFreq = pCHarmonic[iBestCandidate].fFreq / iRefHarmonic; fHarmFreq = fBestFreq * floor(.5 + (pCHarmonic[iPeak].fFreq / iRefHarmonic) / fBestFreq); fDev = fabs(fHarmFreq - (pCHarmonic[iPeak].fFreq / iRefHarmonic)) / fHarmFreq; /* if candidate is far from harmonic from best candidate and * bigger, take it */ if(fDev > .2 && pCHarmonic[iPeak].fMag > pCHarmonic[iBestCandidate].fMag) iBestCandidate = iPeak; /* if frequency deviation is much smaller, take it */ else if(pCHarmonic[iPeak].fFreqDev < .2 * pCHarmonic[iBestCandidate].fFreqDev) iBestCandidate = iPeak; /* if freq. deviation is smaller and bigger amplitude, take it */ else if(pCHarmonic[iPeak].fFreqDev < pCHarmonic[iBestCandidate].fFreqDev && pCHarmonic[iPeak].fMagPerc > pCHarmonic[iBestCandidate].fMagPerc && pCHarmonic[iPeak].fMag > pCHarmonic[iBestCandidate].fMag) iBestCandidate = iPeak; } } return iBestCandidate; } /*! \brief main harmonic detection function * * find a given harmonic peak from a set of spectral peaks, * put the frequency of the fundamental in the current frame * * \param pFrame pointer to current frame * \param fRefFundamental frequency of previous frame * \param pPeakParams pointer to analysis parameters * \todo is it possible to use pSpectralPeaks instead of SMS_AnalFrame? * \todo move pCHarmonic array to SMS_AnalFrame structure - this will allow for analysis of effectiveness from outside this file * This really should only be for sms_analyzeFrame */ sfloat sms_harmDetection(int numPeaks, SMS_Peak* spectralPeaks, sfloat refFundamental, sfloat refHarmonic, sfloat lowestFreq, sfloat highestFreq, int soundType, sfloat minRefHarmMag, sfloat refHarmMagDiffFromMax) { int iPeak = -1, nGoodPeaks = 0, iCandidate, iBestCandidate; sfloat peakFreq=0; SMS_HarmCandidate pCHarmonic[N_HARM_PEAKS]; /* find all possible candidates to use as harmonic reference */ lowestFreq = lowestFreq * refHarmonic; highestFreq = highestFreq * refHarmonic; while((peakFreq < highestFreq) && (iPeak < numPeaks - 1)) { iPeak++; peakFreq = spectralPeaks[iPeak].fFreq; if(peakFreq > highestFreq) break; /* no more peaks */ if(spectralPeaks[iPeak].fMag <= 0) /*!< \bug sfloat comparison to zero */ break; /* peak too low */ if(peakFreq < lowestFreq) continue; /* if previous fundamental look only around it */ if(refFundamental > 0 && fabs(peakFreq - (refHarmonic * refFundamental)) / refFundamental > .5) continue; iCandidate = GoodCandidate(iPeak, numPeaks, spectralPeaks, pCHarmonic, nGoodPeaks, soundType, refFundamental, minRefHarmMag, refHarmMagDiffFromMax, refHarmonic); /* good candiate found */ if(iCandidate == 1) nGoodPeaks++; /* a perfect candiate found */ else if(iCandidate == -2) { nGoodPeaks++; break; } } /* if no candidate for fundamental, continue */ if(nGoodPeaks == 0) return -1; /* if only 1 candidate for fundamental take it */ else if(nGoodPeaks == 1) return pCHarmonic[0].fFreq / refHarmonic; /* if more than one candidate choose the best one */ else { iBestCandidate = GetBestCandidate(pCHarmonic, refHarmonic, nGoodPeaks, refFundamental); return pCHarmonic[iBestCandidate].fFreq / refHarmonic; } }