annotate vamp-hostsdk/PluginBufferingAdapter.h @ 241:70e6826adc64

* Add Power Spectrum example plugin

/* -*- 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 2006-2007 Chris Cannam and QMUL.
    This file by Mark Levy and Chris Cannam, Copyright 2007-2008 QMUL.
  
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    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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*/

#ifndef _VAMP_PLUGIN_BUFFERING_ADAPTER_H_
#define _VAMP_PLUGIN_BUFFERING_ADAPTER_H_

#include "PluginWrapper.h"

namespace Vamp {
	
namespace HostExt {
		
/**
 * \class PluginBufferingAdapter PluginBufferingAdapter.h <vamp-hostsdk/PluginBufferingAdapter.h>
 *
 * PluginBufferingAdapter is a Vamp plugin adapter that allows plugins
 * to be used by a host supplying an audio stream in non-overlapping
 * buffers of arbitrary size.
 *
 * A host using PluginBufferingAdapter may ignore the preferred step
 * and block size reported by the plugin, and still expect the plugin
 * to run.  The value of blockSize and stepSize passed to initialise
 * should be the size of the buffer which the host will supply; the
 * stepSize should be equal to the blockSize.
 *
 * If the internal step size used for the plugin differs from that
 * supplied by the host, the adapter will modify the sample type and
 * rate specifications for the plugin outputs appropriately, and set
 * timestamps on the output features for outputs that formerly used a
 * different sample rate specification.  This is necessary in order to
 * obtain correct time stamping.
 * 
 * In other respects, the PluginBufferingAdapter behaves identically
 * to the plugin that it wraps. The wrapped plugin will be deleted
 * when the wrapper is deleted.
 */
		
class PluginBufferingAdapter : public PluginWrapper
{
public:
    PluginBufferingAdapter(Plugin *plugin); // I take ownership of plugin
    virtual ~PluginBufferingAdapter();

    /**
     * Return the preferred step size for this adapter.
     * 
     * Because of the way this adapter works, its preferred step size
     * will always be the same as its preferred block size.  This may
     * or may not be the same as the preferred step size of the
     * underlying plugin, which may be obtained by calling
     * getPluginPreferredStepSize().
     */
    size_t getPreferredStepSize() const;

    /**
     * Return the preferred block size for this adapter.
     * 
     * This may or may not be the same as the preferred block size of
     * the underlying plugin, which may be obtained by calling
     * getPluginPreferredBlockSize().
     *
     * Note that this adapter may be initialised with any block size,
     * not just its supposedly preferred one.
     */
    size_t getPreferredBlockSize() const;

    /**
     * Initialise the adapter (and therefore the plugin) for the given
     * number of channels.  Initialise the adapter for the given step
     * and block size, which must be equal.
     *
     * The step and block size used for the underlying plugin will
     * depend on its preferences, or any values previously passed to
     * setPluginStepSize and setPluginBlockSize.
     */
    bool initialise(size_t channels, size_t stepSize, size_t blockSize);

    /**
     * Return the preferred step size of the plugin wrapped by this
     * adapter.
     *
     * This is included mainly for informational purposes.  This value
     * is not likely to be a valid step size for the adapter itself,
     * and it is not usually of any use in interpreting the results
     * (because the adapter re-writes OneSamplePerStep outputs to
     * FixedSampleRate so that the hop size no longer needs to be
     * known beforehand in order to interpret them).
     */
    size_t getPluginPreferredStepSize() const;

    /** 
     * Return the preferred block size of the plugin wrapped by this
     * adapter.
     *
     * This is included mainly for informational purposes.
     */
    size_t getPluginPreferredBlockSize() const;

    /**
     * Set the step size that will be used for the underlying plugin
     * when initialise() is called.  If this is not set, the plugin's
     * own preferred step size will be used.  You will not usually
     * need to call this function.  If you do call it, it must be
     * before the first call to initialise().
     */
    void setPluginStepSize(size_t stepSize);

    /**
     * Set the block size that will be used for the underlying plugin
     * when initialise() is called.  If this is not set, the plugin's
     * own preferred block size will be used.  You will not usually
     * need to call this function.  If you do call it, it must be
     * before the first call to initialise().
     */
    void setPluginBlockSize(size_t blockSize);

    /**
     * Return the step and block sizes that were actually used when
     * initialising the underlying plugin.
     *
     * This is included mainly for informational purposes.  You will
     * not usually need to call this function.  If this is called
     * before initialise(), it will return 0 for both values.  If it
     * is called after a failed call to initialise(), it will return
     * the values that were used in the failed call to the plugin's
     * initialise() function.
     */
    void getActualStepAndBlockSizes(size_t &stepSize, size_t &blockSize);

    OutputList getOutputDescriptors() const;

    void reset();

    FeatureSet process(const float *const *inputBuffers, RealTime timestamp);
    
    FeatureSet getRemainingFeatures();
    
protected:
    class Impl;
    Impl *m_impl;
};
    
}

}

#endif