holger@0: function shifts = midiPitch2Shift(midiPitches, tuningFreqInHz, binFreqsCQT)
holger@0: % shifts = midiPitch2Shift(midiPitches, tuningFreqInHz, binFreqsCQT)
holger@0: % 
holger@0: % converts midi pitch to shift values in constant-Q vector.
holger@0: % shifts for pitches that below the lowest or above the highest CQT
holger@0: % frequency are set to a value of -1
holger@0: 
holger@0: numMidiPitches = length(midiPitches);
holger@0: numFreqsCQT    = length(binFreqsCQT);
holger@0: 
holger@0: pitchF0s = midiPitch2Freq(midiPitches, tuningFreqInHz);
holger@0: outOfBoundsPitches = (pitchF0s < binFreqsCQT(1) | pitchF0s > binFreqsCQT(end));
holger@0: if any(outOfBoundsPitches)
holger@0:     warning('F0s of some midi pitches lie outside the constant-Q spectrogram frequency range');
holger@0: end
holger@0:    
holger@0: freqRatios = repmat(binFreqsCQT, 1, numMidiPitches) ./ repmat(pitchF0s', numFreqsCQT, 1);
holger@0: freqRatios(freqRatios < 1) = 1 ./ freqRatios(freqRatios < 1);
holger@0: 
holger@0: [dummy shifts] = min(abs(freqRatios), [], 1);
holger@0: shifts = shifts - 1; % 'no shift' is defined as 0
holger@0: shifts(outOfBoundsPitches) = -1;
holger@0: shifts = shifts';