annotate vamp-sdk/hostext/PluginInputDomainAdapter.cpp @ 63:c747d9b97af3 host-factory-stuff

* documentation

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Vamp

    An API for audio analysis and feature extraction plugins.

    Centre for Digital Music, Queen Mary, University of London.
    Copyright 2006 Chris Cannam.
  
    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use, copy,
    modify, merge, publish, distribute, sublicense, and/or sell copies
    of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Except as contained in this notice, the names of the Centre for
    Digital Music; Queen Mary, University of London; and Chris Cannam
    shall not be used in advertising or otherwise to promote the sale,
    use or other dealings in this Software without prior written
    authorization.
*/

#include "PluginInputDomainAdapter.h"

#include <cmath>

namespace Vamp {

namespace HostExt {

PluginInputDomainAdapter::PluginInputDomainAdapter(Plugin *plugin) :
    PluginWrapper(plugin),
    m_channels(0),
    m_blockSize(0),
    m_freqbuf(0)
{
}

PluginInputDomainAdapter::~PluginInputDomainAdapter()
{
}
    
bool
PluginInputDomainAdapter::initialise(size_t channels, size_t stepSize, size_t blockSize)
{
    if (m_plugin->getInputDomain() == TimeDomain) {

        m_blockSize = blockSize;
        m_channels = channels;

        return m_plugin->initialise(channels, stepSize, blockSize);
    }

    if (blockSize < 2) {
        std::cerr << "ERROR: Vamp::HostExt::PluginInputDomainAdapter::initialise: blocksize < 2 not supported" << std::endl;
        return false;
    }                
        
    if (blockSize & (blockSize-1)) {
        std::cerr << "ERROR: Vamp::HostExt::PluginInputDomainAdapter::initialise: non-power-of-two\nblocksize " << blockSize << " not supported" << std::endl;
        return false;
    }

    if (m_channels > 0) {
        for (size_t c = 0; c < m_channels; ++c) {
            delete[] m_freqbuf[c];
        }
        delete[] m_freqbuf;
        delete[] m_ri;
        delete[] m_ro;
        delete[] m_io;
    }

    m_blockSize = blockSize;
    m_channels = channels;

    m_freqbuf = new float *[m_channels];
    for (size_t c = 0; c < m_channels; ++c) {
        m_freqbuf[c] = new float[m_blockSize + 2];
    }
    m_ri = new double[m_blockSize];
    m_ro = new double[m_blockSize];
    m_io = new double[m_blockSize];

    return m_plugin->initialise(channels, stepSize, blockSize);
}

Plugin::InputDomain
PluginInputDomainAdapter::getInputDomain() const
{
    return TimeDomain;
}

size_t
PluginInputDomainAdapter::getPreferredStepSize() const
{
    size_t step = m_plugin->getPreferredStepSize();

    if (step == 0 && (m_plugin->getInputDomain() == FrequencyDomain)) {
        step = getPreferredBlockSize() / 2;
    }

    return step;
}

size_t
PluginInputDomainAdapter::getPreferredBlockSize() const
{
    size_t block = m_plugin->getPreferredBlockSize();

    if (m_plugin->getInputDomain() == FrequencyDomain) {
        if (block == 0) {
            block = 1024;
        } else {
            block = makeBlockSizeAcceptable(block);
        }
    }

    return block;
}

size_t
PluginInputDomainAdapter::makeBlockSizeAcceptable(size_t blockSize) const
{
    if (blockSize < 2) {

        std::cerr << "WARNING: Vamp::HostExt::PluginInputDomainAdapter::initialise: blocksize < 2 not" << std::endl
                  << "supported, increasing from " << blockSize << " to 2" << std::endl;
        blockSize = 2;
        
    } else if (blockSize & (blockSize-1)) {
            
        // not a power of two, can't handle that with our current fft
        // implementation

        size_t nearest = blockSize;
        size_t power = 0;
        while (nearest > 1) {
            nearest >>= 1;
            ++power;
        }
        nearest = 1;
        while (power) {
            nearest <<= 1;
            --power;
        }
        
        if (blockSize - nearest > (nearest*2) - blockSize) {
            nearest = nearest*2;
        }
        
        std::cerr << "WARNING: Vamp::HostExt::PluginInputDomainAdapter::initialise: non-power-of-two\nblocksize " << blockSize << " not supported, using blocksize " << nearest << " instead" << std::endl;
        blockSize = nearest;
    }

    return blockSize;
}

Plugin::FeatureSet
PluginInputDomainAdapter::process(const float *const *inputBuffers, RealTime timestamp)
{
    if (m_plugin->getInputDomain() == TimeDomain) {
        return m_plugin->process(inputBuffers, timestamp);
    }

    // The timestamp supplied should be (according to the Vamp::Plugin
    // spec) the time of the start of the time-domain input block.
    // However, we want to pass to the plugin an FFT output calculated
    // from the block of samples _centred_ on that timestamp.
    // 
    // We have two options:
    // 
    // 1. Buffer the input, calculating the fft of the values at the
    // passed-in block minus blockSize/2 rather than starting at the
    // passed-in block.  So each time we call process on the plugin,
    // we are passing in the same timestamp as was passed to our own
    // process plugin, but not (the frequency domain representation
    // of) the same set of samples.  Advantages: avoids confusion in
    // the host by ensuring the returned values have timestamps
    // comparable with that passed in to this function (in fact this
    // is pretty much essential for one-value-per-block outputs);
    // consistent with hosts such as SV that deal with the
    // frequency-domain transform themselves.  Disadvantages: means
    // making the not necessarily correct assumption that the samples
    // preceding the first official block are all zero (or some other
    // known value).
    //
    // 2. Increase the passed-in timestamps by half the blocksize.  So
    // when we call process, we are passing in the frequency domain
    // representation of the same set of samples as passed to us, but
    // with a different timestamp.  Advantages: simplicity; avoids
    // iffy assumption mentioned above.  Disadvantages: inconsistency
    // with SV in cases where stepSize != blockSize/2; potential
    // confusion arising from returned timestamps being calculated
    // from the adjusted input timestamps rather than the original
    // ones (and inaccuracy where the returned timestamp is implied,
    // as in one-value-per-block).
    //
    // Neither way is ideal, but I don't think either is strictly
    // incorrect either.  I think this is just a case where the same
    // plugin can legitimately produce differing results from the same
    // input data, depending on how that data is packaged.
    // 
    // We'll go for option 2, adjusting the timestamps.  Note in
    // particular that this means some results can differ from those
    // produced by SV.

    std::cerr << "PluginInputDomainAdapter: sampleRate " << m_inputSampleRate << ", blocksize " << m_blockSize << ", adjusting time from " << timestamp;

    timestamp = timestamp + RealTime::frame2RealTime(m_blockSize/2,
                                                     m_inputSampleRate);

    std::cerr << " to " << timestamp << std::endl;

    for (size_t c = 0; c < m_channels; ++c) {

        for (size_t i = 0; i < m_blockSize; ++i) {
            // Hanning window
            m_ri[i] = double(inputBuffers[c][i])
                * (0.50 - 0.50 * cos((2 * M_PI * i)
                                     / m_blockSize));
        }

        for (size_t i = 0; i < m_blockSize/2; ++i) {
            // FFT shift
            double value = m_ri[i];
            m_ri[i] = m_ri[i + m_blockSize/2];
            m_ri[i + m_blockSize/2] = value;
        }

        fft(m_blockSize, false, m_ri, 0, m_ro, m_io);

        for (size_t i = 0; i <= m_blockSize/2; ++i) {
            m_freqbuf[c][i * 2] = m_ro[i];
            m_freqbuf[c][i * 2 + 1] = m_io[i];
        }
    }

    return m_plugin->process(m_freqbuf, timestamp);
}

void
PluginInputDomainAdapter::fft(unsigned int n, bool inverse,
                              double *ri, double *ii, double *ro, double *io)
{
    if (!ri || !ro || !io) return;

    unsigned int bits;
    unsigned int i, j, k, m;
    unsigned int blockSize, blockEnd;

    double tr, ti;

    if (n < 2) return;
    if (n & (n-1)) return;

    double angle = 2.0 * M_PI;
    if (inverse) angle = -angle;

    for (i = 0; ; ++i) {
	if (n & (1 << i)) {
	    bits = i;
	    break;
	}
    }

    static unsigned int tableSize = 0;
    static int *table = 0;

    if (tableSize != n) {

	delete[] table;

	table = new int[n];

	for (i = 0; i < n; ++i) {
	
	    m = i;

	    for (j = k = 0; j < bits; ++j) {
		k = (k << 1) | (m & 1);
		m >>= 1;
	    }

	    table[i] = k;
	}

	tableSize = n;
    }

    if (ii) {
	for (i = 0; i < n; ++i) {
	    ro[table[i]] = ri[i];
	    io[table[i]] = ii[i];
	}
    } else {
	for (i = 0; i < n; ++i) {
	    ro[table[i]] = ri[i];
	    io[table[i]] = 0.0;
	}
    }

    blockEnd = 1;

    for (blockSize = 2; blockSize <= n; blockSize <<= 1) {

	double delta = angle / (double)blockSize;
	double sm2 = -sin(-2 * delta);
	double sm1 = -sin(-delta);
	double cm2 = cos(-2 * delta);
	double cm1 = cos(-delta);
	double w = 2 * cm1;
	double ar[3], ai[3];

	for (i = 0; i < n; i += blockSize) {

	    ar[2] = cm2;
	    ar[1] = cm1;

	    ai[2] = sm2;
	    ai[1] = sm1;

	    for (j = i, m = 0; m < blockEnd; j++, m++) {

		ar[0] = w * ar[1] - ar[2];
		ar[2] = ar[1];
		ar[1] = ar[0];

		ai[0] = w * ai[1] - ai[2];
		ai[2] = ai[1];
		ai[1] = ai[0];

		k = j + blockEnd;
		tr = ar[0] * ro[k] - ai[0] * io[k];
		ti = ar[0] * io[k] + ai[0] * ro[k];

		ro[k] = ro[j] - tr;
		io[k] = io[j] - ti;

		ro[j] += tr;
		io[j] += ti;
	    }
	}

	blockEnd = blockSize;
    }

    if (inverse) {

	double denom = (double)n;

	for (i = 0; i < n; i++) {
	    ro[i] /= denom;
	    io[i] /= denom;
	}
    }
}

}
        
}