annotate vamp-sdk/hostext/PluginBufferingAdapter.h @ 169:af8e59f43d1d

* Add capability for setting underlying plugin's step and block sizes
  to PluginBufferingAdapter

/* -*- 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, Copyright 2007 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,
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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-sdk/hostext/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;

    /**
     * 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);

    /**
     * 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);

    OutputList getOutputDescriptors() const;

    void reset();

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

}

#endif