annotate examples/PowerSpectrum.cpp @ 415:1522e2f6d700

Fix handling of output sample rate in buffering adapter in case where SampleType is Fixed but no sample rate provided (which is invalid behaviour from the plugin, but we might as well do the right thing with it)

/* -*- 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 2008 QMUL.
  
    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
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    of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

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    Except as contained in this notice, the names of the Centre for
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*/

#include "PowerSpectrum.h"

using std::string;
using std::cerr;
using std::endl;

#include <math.h>

PowerSpectrum::PowerSpectrum(float inputSampleRate) :
    Plugin(inputSampleRate),
    m_blockSize(0)
{
}

PowerSpectrum::~PowerSpectrum()
{
}

string
PowerSpectrum::getIdentifier() const
{
    return "powerspectrum";
}

string
PowerSpectrum::getName() const
{
    return "Simple Power Spectrum";
}

string
PowerSpectrum::getDescription() const
{
    return "Return the power spectrum of a signal";
}

string
PowerSpectrum::getMaker() const
{
    return "Vamp SDK Example Plugins";
}

int
PowerSpectrum::getPluginVersion() const
{
    return 1;
}

string
PowerSpectrum::getCopyright() const
{
    return "Freely redistributable (BSD license)";
}

bool
PowerSpectrum::initialise(size_t channels, size_t, size_t blockSize)
{
    if (channels < getMinChannelCount() ||
	channels > getMaxChannelCount()) return false;

    m_blockSize = blockSize;

    return true;
}

void
PowerSpectrum::reset()
{
}

PowerSpectrum::OutputList
PowerSpectrum::getOutputDescriptors() const
{
    OutputList list;

    OutputDescriptor d;
    d.identifier = "powerspectrum";
    d.name = "Power Spectrum";
    d.description = "Power values of the frequency spectrum bins calculated from the input signal";
    d.unit = "";
    d.hasFixedBinCount = true;
    if (m_blockSize == 0) {
        // Just so as not to return "1".  This is the bin count that
        // would result from a block size of 1024, which is a likely
        // default -- but the host should always set the block size
        // before querying the bin count for certain.
        d.binCount = 513;
    } else {
        d.binCount = m_blockSize / 2 + 1;
    }
    d.hasKnownExtents = false;
    d.isQuantized = false;
    d.sampleType = OutputDescriptor::OneSamplePerStep;
    list.push_back(d);

    return list;
}

PowerSpectrum::FeatureSet
PowerSpectrum::process(const float *const *inputBuffers, Vamp::RealTime)
{
    FeatureSet fs;

    if (m_blockSize == 0) {
	cerr << "ERROR: PowerSpectrum::process: Not initialised" << endl;
	return fs;
    }

    size_t n = m_blockSize / 2 + 1;
    const float *fbuf = inputBuffers[0];

    Feature feature;
    feature.hasTimestamp = false;
    feature.values.reserve(n); // optional

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

	double real = fbuf[i * 2];
	double imag = fbuf[i * 2 + 1];

        feature.values.push_back(real * real + imag * imag);
    }

    fs[0].push_back(feature);

    return fs;
}

PowerSpectrum::FeatureSet
PowerSpectrum::getRemainingFeatures()
{
    return FeatureSet();
}