annotate src/ConstantQ.cpp @ 150:242bf7bc38ce

Avoid failing if min and max frequency are identical

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
/*
    Constant-Q library
    Copyright (c) 2013-2014 Queen Mary, University of London

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*/

#include "ConstantQ.h"

#include "CQKernel.h"

#include "dsp/Resampler.h"
#include "dsp/MathUtilities.h"
#include "dsp/FFT.h"

#include <algorithm>
#include <iostream>
#include <stdexcept>

using std::vector;
using std::cerr;
using std::endl;

//#define DEBUG_CQ 1

ConstantQ::ConstantQ(CQParameters params) :
    m_inparams(params),
    m_sampleRate(params.sampleRate),
    m_maxFrequency(params.maxFrequency),
    m_minFrequency(params.minFrequency),
    m_binsPerOctave(params.binsPerOctave),
    m_fft(0)
{
    if (m_minFrequency <= 0.0 || m_maxFrequency <= 0.0) {
        throw std::invalid_argument("Frequency extents must be positive");
    }

    initialise();
}

ConstantQ::~ConstantQ()
{
    delete m_fft;
    for (int i = 0; i < (int)m_decimators.size(); ++i) {
        delete m_decimators[i];
    }
    delete m_kernel;
}

double
ConstantQ::getMinFrequency() const
{
    return m_p.minFrequency / pow(2.0, m_octaves - 1);
}

double
ConstantQ::getBinFrequency(double bin) const
{
    // our bins are returned in high->low order
    bin = (getBinsPerOctave() * getOctaves()) - bin - 1;
    return getMinFrequency() * pow(2, (bin / getBinsPerOctave()));
}

void
ConstantQ::initialise()
{
    m_octaves = int(ceil(log2(m_maxFrequency / m_minFrequency)));

    if (m_octaves < 1) {
        m_kernel = 0; // incidentally causing isValid() to return false
        return;
    }

    m_kernel = new CQKernel(m_inparams);
    m_p = m_kernel->getProperties();
    
    if (!m_kernel->isValid()) {
        return;
    }

    // Use exact powers of two for resampling rates. They don't have
    // to be related to our actual samplerate: the resampler only
    // cares about the ratio, but it only accepts integer source and
    // target rates, and if we start from the actual samplerate we
    // risk getting non-integer rates for lower octaves

    int sourceRate = pow(2, m_octaves);
    vector<int> latencies;

    // top octave, no resampling
    latencies.push_back(0);
    m_decimators.push_back(0);

    for (int i = 1; i < m_octaves; ++i) {

        int factor = pow(2, i);

        Resampler *r = new Resampler
            (sourceRate, sourceRate / factor, 50, 0.05);

#ifdef DEBUG_CQ
        cerr << "forward: octave " << i << ": resample from " << sourceRate << " to " << sourceRate / factor << endl;
#endif

        // We need to adapt the latencies so as to get the first input
        // sample to be aligned, in time, at the decimator output
        // across all octaves.
        // 
        // Our decimator uses a linear phase filter, but being causal
        // it is not zero phase: it has a latency that depends on the
        // decimation factor. Those latencies have been calculated
        // per-octave and are available to us in the latencies
        // array. Left to its own devices, the first input sample will
        // appear at output sample 0 in the highest octave (where no
        // decimation is needed), sample number latencies[1] in the
        // next octave down, latencies[2] in the next one, etc. We get
        // to apply some artificial per-octave latency after the
        // decimator in the processing chain, in order to compensate
        // for the differing latencies associated with different
        // decimation factors. How much should we insert?
        //
        // The outputs of the decimators are at different rates (in
        // terms of the relation between clock time and samples) and
        // we want them aligned in terms of time. So, for example, a
        // latency of 10 samples with a decimation factor of 2 is
        // equivalent to a latency of 20 with no decimation -- they
        // both result in the first output sample happening at the
        // same equivalent time in milliseconds.
	// 
	// So here we record the latency added by the decimator, in
	// terms of the sample rate of the undecimated signal. Then we
	// use that to compensate in a moment, when we've discovered
	// what the longest latency across all octaves is.

        latencies.push_back(r->getLatency() * factor);
        m_decimators.push_back(r);
    }

    m_bigBlockSize = m_p.fftSize * pow(2, m_octaves - 1);

    // Now add in the extra padding and compensate for hops that must
    // be dropped in order to align the atom centres across
    // octaves. Again this is a bit trickier because we are doing it
    // at input rather than output and so must work in per-octave
    // sample rates rather than output blocks

    int emptyHops = m_p.firstCentre / m_p.atomSpacing;

    vector<int> drops;
    for (int i = 0; i < m_octaves; ++i) {
	int factor = pow(2, i);
	int dropHops = emptyHops * pow(2, m_octaves - i - 1) - emptyHops;
	int drop = ((dropHops * m_p.fftHop) * factor) / m_p.atomsPerFrame;
	drops.push_back(drop);
    }

    int maxLatPlusDrop = 0;
    for (int i = 0; i < m_octaves; ++i) {
	int latPlusDrop = latencies[i] + drops[i];
	if (latPlusDrop > maxLatPlusDrop) maxLatPlusDrop = latPlusDrop;
    }

    int totalLatency = maxLatPlusDrop;

    int lat0 = totalLatency - latencies[0] - drops[0];
    totalLatency = ceil(double(lat0 / m_p.fftHop) * m_p.fftHop)
	+ latencies[0] + drops[0];

    // We want (totalLatency - latencies[i]) to be a multiple of 2^i
    // for each octave i, so that we do not end up with fractional
    // octave latencies below. In theory this is hard, in practice if
    // we ensure it for the last octave we should be OK.
    double finalOctLat = latencies[m_octaves-1];
    double finalOctFact = pow(2, m_octaves-1);
    totalLatency =
        int(round(finalOctLat +
                  finalOctFact *
                  ceil((totalLatency - finalOctLat) / finalOctFact)));

#ifdef DEBUG_CQ
    cerr << "total latency = " << totalLatency << endl;
#endif

    // Padding as in the reference (will be introduced with the
    // latency compensation in the loop below)
    m_outputLatency = totalLatency + m_bigBlockSize
	- m_p.firstCentre * pow(2, m_octaves-1);

#ifdef DEBUG_CQ
    cerr << "m_bigBlockSize = " << m_bigBlockSize << ", firstCentre = "
	 << m_p.firstCentre << ", m_octaves = " << m_octaves
         << ", so m_outputLatency = " << m_outputLatency << endl;
#endif

    for (int i = 0; i < m_octaves; ++i) {

	double factor = pow(2, i);

	// Calculate the difference between the total latency applied
	// across all octaves, and the existing latency due to the
	// decimator for this octave, and then convert it back into
	// the sample rate appropriate for the output latency of this
	// decimator -- including one additional big block of padding
	// (as in the reference).

	double octaveLatency =
	    double(totalLatency - latencies[i] - drops[i]
		   + m_bigBlockSize) / factor;

#ifdef DEBUG_CQ
        cerr << "octave " << i << ": resampler latency = " << latencies[i]
             << ", drop " << drops[i] << " (/factor = " << drops[i]/factor
             << "), octaveLatency = " << octaveLatency << " -> "
             << int(round(octaveLatency)) << " (diff * factor = "
             << (octaveLatency - round(octaveLatency)) << " * "
             << factor << " = "
             << (octaveLatency - round(octaveLatency)) * factor << ")" << endl;

        cerr << "double(" << totalLatency << " - " 
             << latencies[i] << " - " << drops[i] << " + " 
             << m_bigBlockSize << ") / " << factor << " = " 
             << octaveLatency << endl;
#endif

        m_buffers.push_back
            (RealSequence(int(round(octaveLatency)), 0.0));
    }

    m_fft = new FFTReal(m_p.fftSize);
}

ConstantQ::ComplexBlock
ConstantQ::process(const RealSequence &td)
{
    m_buffers[0].insert(m_buffers[0].end(), td.begin(), td.end());

    for (int i = 1; i < m_octaves; ++i) {
        RealSequence dec = m_decimators[i]->process(td.data(), td.size());
        m_buffers[i].insert(m_buffers[i].end(), dec.begin(), dec.end());
    }

    ComplexBlock out;

    while (true) {

	// We could have quite different remaining sample counts in
	// different octaves, because (apart from the predictable
	// added counts for decimator output on each block) we also
	// have variable additional latency per octave
	bool enough = true;
	for (int i = 0; i < m_octaves; ++i) {
	    int required = m_p.fftSize * pow(2, m_octaves - i - 1);
	    if ((int)m_buffers[i].size() < required) {
		enough = false;
	    }
	}
	if (!enough) break;

        int base = out.size();
        int totalColumns = pow(2, m_octaves - 1) * m_p.atomsPerFrame;
        for (int i = 0; i < totalColumns; ++i) {
            out.push_back(ComplexColumn());
        }

        for (int octave = 0; octave < m_octaves; ++octave) {

            int blocksThisOctave = pow(2, (m_octaves - octave - 1));

            for (int b = 0; b < blocksThisOctave; ++b) {
                ComplexBlock block = processOctaveBlock(octave);
                
                for (int j = 0; j < m_p.atomsPerFrame; ++j) {

                    int target = base +
			    (b * (totalColumns / blocksThisOctave) + 
			     (j * ((totalColumns / blocksThisOctave) /
				   m_p.atomsPerFrame)));

                    while (int(out[target].size()) < 
                           m_p.binsPerOctave * (octave + 1)) {
                        out[target].push_back(Complex());
                    }
                    
                    for (int i = 0; i < m_p.binsPerOctave; ++i) {
                        out[target][m_p.binsPerOctave * octave + i] = 
                            block[j][m_p.binsPerOctave - i - 1];
                    }
                }
            }
        }
    }

    return out;
}

ConstantQ::ComplexBlock
ConstantQ::getRemainingOutput()
{
    // Same as padding added at start, though rounded up
    int pad = ceil(double(m_outputLatency) / m_bigBlockSize) * m_bigBlockSize;
    RealSequence zeros(pad, 0.0);
    return process(zeros);
}

ConstantQ::ComplexBlock
ConstantQ::processOctaveBlock(int octave)
{
    RealSequence ro(m_p.fftSize, 0.0);
    RealSequence io(m_p.fftSize, 0.0);

    m_fft->forward(m_buffers[octave].data(), ro.data(), io.data());

    RealSequence shifted;
    shifted.insert(shifted.end(), 
                   m_buffers[octave].begin() + m_p.fftHop,
                   m_buffers[octave].end());
    m_buffers[octave] = shifted;

    ComplexSequence cv;
    for (int i = 0; i < m_p.fftSize; ++i) {
        cv.push_back(Complex(ro[i], io[i]));
    }

    ComplexSequence cqrowvec = m_kernel->processForward(cv);

    // Reform into a column matrix
    ComplexBlock cqblock;
    for (int j = 0; j < m_p.atomsPerFrame; ++j) {
        cqblock.push_back(ComplexColumn());
        for (int i = 0; i < m_p.binsPerOctave; ++i) {
            cqblock[j].push_back(cqrowvec[i * m_p.atomsPerFrame + j]);
        }
    }

    return cqblock;
}