annotate vamp-hostsdk/PluginSummarisingAdapter.h @ 263:4454843ff384

* OK, we're going to have to place the host stuff in its own namespace
  too.  Otherwise our new SV build on OSX fails to load old plugins
  because they pull in the host namespace PluginBase and thus report
  the wrong Vamp version... *sigh*

/* -*- 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 2006-2008 Chris Cannam and QMUL.
  
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    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:

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

#ifndef _VAMP_PLUGIN_SUMMARISING_ADAPTER_H_
#define _VAMP_PLUGIN_SUMMARISING_ADAPTER_H_

#include "hostguard.h"
#include "PluginWrapper.h"

#include <set>

_VAMP_SDK_HOSTSPACE_BEGIN(PluginSummarisingAdapter.h)

namespace Vamp {

namespace HostExt {

/**
 * \class PluginSummarisingAdapter PluginSummarisingAdapter.h <vamp-hostsdk/PluginSummarisingAdapter.h>
 *
 * PluginSummarisingAdapter is a Vamp plugin adapter that provides
 * summarisation methods such as mean and median averages of output
 * features, for use in any context where an available plugin produces
 * individual values but the result that is actually needed is some
 * sort of aggregate.
 *
 * To make use of PluginSummarisingAdapter, the host should configure,
 * initialise and run the plugin through the adapter interface just as
 * normal.  Then, after the process and getRemainingFeatures methods
 * have been properly called and processing is complete, the host may
 * call getSummaryForOutput or getSummaryForAllOutputs to obtain
 * summarised features: averages, maximum values, etc, depending on
 * the SummaryType passed to the function.
 *
 * By default PluginSummarisingAdapter calculates a single summary of
 * each output's feature across the whole duration of processed audio.
 * A host needing summaries of sub-segments of the whole audio may
 * call setSummarySegmentBoundaries before retrieving the summaries,
 * providing a list of times such that one summary will be provided
 * for each segment between two consecutive times.
 *
 * PluginSummarisingAdapter is straightforward rather than fast.  It
 * calculates all of the summary types for all outputs always, and
 * then returns only the ones that are requested.  It is designed on
 * the basis that, for most features, summarising and storing
 * summarised results is far cheaper than calculating the results in
 * the first place.  If this is not true for your particular feature,
 * PluginSummarisingAdapter may not be the best approach for you.
 *
 * \note This class was introduced in version 2.0 of the Vamp plugin SDK.
 */

class PluginSummarisingAdapter : public PluginWrapper
{
public:
    /**
     * Construct a PluginSummarisingAdapter wrapping the given plugin.
     * The adapter takes ownership of the plugin, which will be
     * deleted when the adapter is deleted.
     */
    PluginSummarisingAdapter(Plugin *plugin); 
    virtual ~PluginSummarisingAdapter();

    bool initialise(size_t channels, size_t stepSize, size_t blockSize);

    FeatureSet process(const float *const *inputBuffers, RealTime timestamp);
    FeatureSet getRemainingFeatures();

    typedef std::set<RealTime> SegmentBoundaries;

    /**
     * Specify a series of segment boundaries, such that one summary
     * will be returned for each of the contiguous intra-boundary
     * segments.  This function must be called before
     * getSummaryForOutput or getSummaryForAllOutputs.
     * 
     * Note that you cannot retrieve results with multiple different
     * segmentations by repeatedly calling this function followed by
     * one of the getSummary functions.  The summaries are all
     * calculated at the first call to any getSummary function, and
     * once the summaries have been calculated, they remain
     * calculated.
     */
    void setSummarySegmentBoundaries(const SegmentBoundaries &);

    enum SummaryType {
        Minimum            = 0,
        Maximum            = 1,
        Mean               = 2,
        Median             = 3,
        Mode               = 4,
        Sum                = 5,
        Variance           = 6,
        StandardDeviation  = 7,
        Count              = 8,

        UnknownSummaryType = 999
    };

    /**
     * AveragingMethod indicates how the adapter should handle
     * average-based summaries of features whose results are not
     * equally spaced in time.
     *
     * If SampleAverage is specified, summary types based on averages
     * will be calculated by treating each result individually without
     * regard to its time: for example, the mean will be the sum of
     * all values divided by the number of values.
     *
     * If ContinuousTimeAverage is specified, each feature will be
     * considered to have a duration, either as specified in the
     * feature's duration field, or until the following feature: thus,
     * for example, the mean will be the sum of the products of values
     * and durations, divided by the total duration.
     *
     * Although SampleAverage is useful for many types of feature,
     * ContinuousTimeAverage is essential for some situations, for
     * example finding the result that spans the largest proportion of
     * the input given a feature that emits a new result only when the
     * value changes (the modal value integrated over time).
     */
    enum AveragingMethod {
        SampleAverage         = 0,
        ContinuousTimeAverage = 1,
    };

    /**
     * Return summaries of the features that were returned on the
     * given output, using the given SummaryType and AveragingMethod.
     *
     * The plugin must have been fully run (process() and
     * getRemainingFeatures() calls all made as appropriate) before
     * this function is called.
     */
    FeatureList getSummaryForOutput(int output,
                                    SummaryType type,
                                    AveragingMethod method = SampleAverage);

    /**
     * Return summaries of the features that were returned on all of
     * the plugin's outputs, using the given SummaryType and
     * AveragingMethod.
     *
     * The plugin must have been fully run (process() and
     * getRemainingFeatures() calls all made as appropriate) before
     * this function is called.
     */
    FeatureSet getSummaryForAllOutputs(SummaryType type,
                                       AveragingMethod method = SampleAverage);

protected:
    class Impl;
    Impl *m_impl;
};

}

}

_VAMP_SDK_HOSTSPACE_END(PluginSummarisingAdapter.h)

#endif