Chris@14: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@14: 
Chris@14: /*
Chris@14:     Vamp
Chris@14: 
Chris@14:     An API for audio analysis and feature extraction plugins.
Chris@14: 
Chris@14:     Centre for Digital Music, Queen Mary, University of London.
Chris@14:     Copyright 2006 Chris Cannam.
Chris@14:   
Chris@14:     Permission is hereby granted, free of charge, to any person
Chris@14:     obtaining a copy of this software and associated documentation
Chris@14:     files (the "Software"), to deal in the Software without
Chris@14:     restriction, including without limitation the rights to use, copy,
Chris@14:     modify, merge, publish, distribute, sublicense, and/or sell copies
Chris@14:     of the Software, and to permit persons to whom the Software is
Chris@14:     furnished to do so, subject to the following conditions:
Chris@14: 
Chris@14:     The above copyright notice and this permission notice shall be
Chris@14:     included in all copies or substantial portions of the Software.
Chris@14: 
Chris@14:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@14:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@14:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
Chris@14:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
Chris@14:     ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@14:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@14:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@14: 
Chris@14:     Except as contained in this notice, the names of the Centre for
Chris@14:     Digital Music; Queen Mary, University of London; and Chris Cannam
Chris@14:     shall not be used in advertising or otherwise to promote the sale,
Chris@14:     use or other dealings in this Software without prior written
Chris@14:     authorization.
Chris@14: */
Chris@14: 
Chris@14: #ifndef _VAMP_SDK_PLUGIN_H_
Chris@14: #define _VAMP_SDK_PLUGIN_H_
Chris@14: 
Chris@14: #include <string>
Chris@14: #include <vector>
Chris@14: #include <map>
Chris@14: 
Chris@14: #include "PluginBase.h"
Chris@14: #include "RealTime.h"
Chris@14: 
Chris@14: #include "plugguard.h"
Chris@14: _VAMP_SDK_PLUGSPACE_BEGIN(Plugin.h)
Chris@14: 
Chris@14: namespace Vamp {
Chris@14: 
Chris@14: /**
Chris@14:  * \class Plugin Plugin.h <vamp-sdk/Plugin.h>
Chris@14:  * 
Chris@14:  * Vamp::Plugin is a base class for plugin instance classes
Chris@14:  * that provide feature extraction from audio or related data.
Chris@14:  *
Chris@14:  * In most cases, the input will be audio and the output will be a
Chris@14:  * stream of derived data at a lower sampling resolution than the
Chris@14:  * input.
Chris@14:  *
Chris@14:  * Note that this class inherits several abstract methods from
Chris@14:  * PluginBase.  These must be implemented by the subclass.
Chris@14:  * 
Chris@14:  * 
Chris@14:  * PLUGIN LIFECYCLE
Chris@14:  *
Chris@14:  * Feature extraction plugins are managed differently from real-time
Chris@14:  * plugins (such as VST effects).  The main difference is that the
Chris@14:  * parameters for a feature extraction plugin are configured before
Chris@14:  * the plugin is used, and do not change during use.
Chris@14:  *
Chris@14:  * 1. Host constructs the plugin, passing it the input sample rate.
Chris@14:  * The plugin may do basic initialisation, but should not do anything
Chris@14:  * computationally expensive at this point.  You must make sure your
Chris@14:  * plugin is cheap to construct, otherwise you'll seriously affect the
Chris@14:  * startup performance of almost all hosts.  If you have serious
Chris@14:  * initialisation to do, the proper place is in initialise() (step 5).
Chris@14:  *
Chris@14:  * 2. Host may query the plugin's available outputs.
Chris@14:  *
Chris@14:  * 3. Host queries programs and parameter descriptors, and may set
Chris@14:  * some or all of them.  Parameters that are not explicitly set should
Chris@14:  * take their default values as specified in the parameter descriptor.
Chris@14:  * When a program is set, the parameter values may change and the host
Chris@14:  * will re-query them to check.
Chris@14:  *
Chris@14:  * 4. Host queries the preferred step size, block size and number of
Chris@14:  * channels.  These may all vary depending on the parameter values.
Chris@14:  * (Note however that you cannot make the number of distinct outputs
Chris@14:  * dependent on parameter values.)
Chris@14:  *
Chris@14:  * 5. Plugin is properly initialised with a call to initialise.  This
Chris@14:  * fixes the step size, block size, and number of channels, as well as
Chris@14:  * all of the parameter and program settings.  If the values passed in
Chris@14:  * to initialise do not match the plugin's advertised preferred values
Chris@14:  * from step 4, the plugin may refuse to initialise and return false
Chris@14:  * (although if possible it should accept the new values).  Any
Chris@14:  * computationally expensive setup code should take place here.
Chris@14:  *
Chris@14:  * 6. Host finally checks the number of values, resolution, extents
Chris@14:  * etc per output (which may vary depending on the number of channels,
Chris@14:  * step size and block size as well as the parameter values).
Chris@14:  *
Chris@14:  * 7. Host will repeatedly call the process method to pass in blocks
Chris@14:  * of input data.  This method may return features extracted from that
Chris@14:  * data (if the plugin is causal).
Chris@14:  *
Chris@14:  * 8. Host will call getRemainingFeatures exactly once, after all the
Chris@14:  * input data has been processed.  This may return any non-causal or
Chris@14:  * leftover features.
Chris@14:  *
Chris@14:  * 9. At any point after initialise was called, the host may
Chris@14:  * optionally call the reset method and restart processing.  (This
Chris@14:  * does not mean it can change the parameters, which are fixed from
Chris@14:  * initialise until destruction.)
Chris@14:  *
Chris@14:  * A plugin does not need to handle the case where setParameter or
Chris@14:  * selectProgram is called after initialise has been called.  It's the
Chris@14:  * host's responsibility not to do that.  Similarly, the plugin may
Chris@14:  * safely assume that initialise is called no more than once.
Chris@14:  */
Chris@14: 
Chris@14: class Plugin : public PluginBase
Chris@14: {
Chris@14: public:
Chris@14:     virtual ~Plugin() { }
Chris@14: 
Chris@14:     /**
Chris@14:      * Initialise a plugin to prepare it for use with the given number
Chris@14:      * of input channels, step size (window increment, in sample
Chris@14:      * frames) and block size (window size, in sample frames).
Chris@14:      *
Chris@14:      * The input sample rate should have been already specified at
Chris@14:      * construction time.
Chris@14:      * 
Chris@14:      * Return true for successful initialisation, false if the number
Chris@14:      * of input channels, step size and/or block size cannot be
Chris@14:      * supported.
Chris@14:      */
Chris@14:     virtual bool initialise(size_t inputChannels,
Chris@14: 			    size_t stepSize,
Chris@14: 			    size_t blockSize) = 0;
Chris@14: 
Chris@14:     /**
Chris@14:      * Reset the plugin after use, to prepare it for another clean
Chris@14:      * run.  Not called for the first initialisation (i.e. initialise
Chris@14:      * must also do a reset).
Chris@14:      */
Chris@14:     virtual void reset() = 0;
Chris@14: 
Chris@14:     enum InputDomain { TimeDomain, FrequencyDomain };
Chris@14:     
Chris@14:     /**
Chris@14:      * Get the plugin's required input domain.
Chris@14:      *
Chris@14:      * If this is TimeDomain, the samples provided to the process()
Chris@14:      * function (below) will be in the time domain, as for a
Chris@14:      * traditional audio processing plugin.
Chris@14:      *
Chris@14:      * If this is FrequencyDomain, the host will carry out a windowed
Chris@14:      * FFT of size equal to the negotiated block size on the data
Chris@14:      * before passing the frequency bin data in to process().  The
Chris@14:      * input data for the FFT will be rotated so as to place the
Chris@14:      * origin in the centre of the block.
Chris@14:      * The plugin does not get to choose the window type -- the host
Chris@14:      * will either let the user do so, or will use a Hanning window.
Chris@14:      */
Chris@14:     virtual InputDomain getInputDomain() const = 0;
Chris@14: 
Chris@14:     /**
Chris@14:      * Get the preferred block size (window size -- the number of
Chris@14:      * sample frames passed in each block to the process() function).
Chris@14:      * This should be called before initialise().
Chris@14:      *
Chris@14:      * A plugin that can handle any block size may return 0.  The
Chris@14:      * final block size will be set in the initialise() call.
Chris@14:      */
Chris@14:     virtual size_t getPreferredBlockSize() const { return 0; }
Chris@14: 
Chris@14:     /**
Chris@14:      * Get the preferred step size (window increment -- the distance
Chris@14:      * in sample frames between the start frames of consecutive blocks
Chris@14:      * passed to the process() function) for the plugin.  This should
Chris@14:      * be called before initialise().
Chris@14:      *
Chris@14:      * A plugin may return 0 if it has no particular interest in the
Chris@14:      * step size.  In this case, the host should make the step size
Chris@14:      * equal to the block size if the plugin is accepting input in the
Chris@14:      * time domain.  If the plugin is accepting input in the frequency
Chris@14:      * domain, the host may use any step size.  The final step size
Chris@14:      * will be set in the initialise() call.
Chris@14:      */
Chris@14:     virtual size_t getPreferredStepSize() const { return 0; }
Chris@14: 
Chris@14:     /**
Chris@14:      * Get the minimum supported number of input channels.
Chris@14:      */
Chris@14:     virtual size_t getMinChannelCount() const { return 1; }
Chris@14: 
Chris@14:     /**
Chris@14:      * Get the maximum supported number of input channels.
Chris@14:      */
Chris@14:     virtual size_t getMaxChannelCount() const { return 1; }
Chris@14: 
Chris@14:     struct OutputDescriptor
Chris@14:     {
Chris@14: 	/**
Chris@14: 	 * The name of the output, in computer-usable form.  Should be
Chris@14: 	 * reasonably short and without whitespace or punctuation, using
Chris@14:          * the characters [a-zA-Z0-9_-] only.
Chris@14:          * Example: "zero_crossing_count"
Chris@14: 	 */
Chris@14: 	std::string identifier;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * The human-readable name of the output.
Chris@14:          * Example: "Zero Crossing Counts"
Chris@14: 	 */
Chris@14: 	std::string name;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * A human-readable short text describing the output.  May be
Chris@14:          * empty if the name has said it all already.
Chris@14:          * Example: "The number of zero crossing points per processing block"
Chris@14: 	 */
Chris@14: 	std::string description;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * The unit of the output, in human-readable form.
Chris@14: 	 */
Chris@14: 	std::string unit;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * True if the output has the same number of values per sample
Chris@14: 	 * for every output sample.  Outputs for which this is false
Chris@14: 	 * are unlikely to be very useful in a general-purpose host.
Chris@14: 	 */
Chris@14: 	bool hasFixedBinCount;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * The number of values per result of the output.  Undefined
Chris@14: 	 * if hasFixedBinCount is false.  If this is zero, the output
Chris@14: 	 * is point data (i.e. only the time of each output is of
Chris@14: 	 * interest, the value list will be empty).
Chris@14: 	 */
Chris@14: 	size_t binCount;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * The (human-readable) names of each of the bins, if
Chris@14: 	 * appropriate.  This is always optional.
Chris@14: 	 */
Chris@14: 	std::vector<std::string> binNames;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * True if the results in each output bin fall within a fixed
Chris@14: 	 * numeric range (minimum and maximum values).  Undefined if
Chris@14: 	 * binCount is zero.
Chris@14: 	 */
Chris@14: 	bool hasKnownExtents;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * Minimum value of the results in the output.  Undefined if
Chris@14: 	 * hasKnownExtents is false or binCount is zero.
Chris@14: 	 */
Chris@14: 	float minValue;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * Maximum value of the results in the output.  Undefined if
Chris@14: 	 * hasKnownExtents is false or binCount is zero.
Chris@14: 	 */
Chris@14: 	float maxValue;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * True if the output values are quantized to a particular
Chris@14: 	 * resolution.  Undefined if binCount is zero.
Chris@14: 	 */
Chris@14: 	bool isQuantized;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * Quantization resolution of the output values (e.g. 1.0 if
Chris@14: 	 * they are all integers).  Undefined if isQuantized is false
Chris@14: 	 * or binCount is zero.
Chris@14: 	 */
Chris@14: 	float quantizeStep;
Chris@14: 
Chris@14: 	enum SampleType {
Chris@14: 
Chris@14: 	    /// Results from each process() align with that call's block start
Chris@14: 	    OneSamplePerStep,
Chris@14: 
Chris@14: 	    /// Results are evenly spaced in time (sampleRate specified below)
Chris@14: 	    FixedSampleRate,
Chris@14: 
Chris@14: 	    /// Results are unevenly spaced and have individual timestamps
Chris@14: 	    VariableSampleRate
Chris@14: 	};
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * Positioning in time of the output results.
Chris@14: 	 */
Chris@14: 	SampleType sampleType;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * Sample rate of the output results, as samples per second.
Chris@14: 	 * Undefined if sampleType is OneSamplePerStep.
Chris@14: 	 *
Chris@14: 	 * If sampleType is VariableSampleRate and this value is
Chris@14: 	 * non-zero, then it may be used to calculate a resolution for
Chris@14: 	 * the output (i.e. the "duration" of each sample, in time,
Chris@14: 	 * will be 1/sampleRate seconds).  It's recommended to set
Chris@14: 	 * this to zero if that behaviour is not desired.
Chris@14: 	 */
Chris@14: 	float sampleRate;
Chris@14: 
Chris@14:         /**
Chris@14:          * True if the returned results for this output are known to
Chris@14:          * have a duration field.
Chris@14:          */
Chris@14:         bool hasDuration;
Chris@14: 
Chris@14:         OutputDescriptor() : // defaults for mandatory non-class-type members
Chris@14:             hasFixedBinCount(false), hasKnownExtents(false), isQuantized(false),
Chris@23:             sampleType(OneSamplePerStep), sampleRate(0), hasDuration(false) { }
Chris@14:     };
Chris@14: 
Chris@14:     typedef std::vector<OutputDescriptor> OutputList;
Chris@14: 
Chris@14:     /**
Chris@14:      * Get the outputs of this plugin.  An output's index in this list
Chris@14:      * is used as its numeric index when looking it up in the
Chris@14:      * FeatureSet returned from the process() call.
Chris@14:      */
Chris@14:     virtual OutputList getOutputDescriptors() const = 0;
Chris@14: 
Chris@14:     struct Feature
Chris@14:     {
Chris@14: 	/**
Chris@14: 	 * True if an output feature has its own timestamp.  This is
Chris@14: 	 * mandatory if the output has VariableSampleRate, optional if
Chris@14: 	 * the output has FixedSampleRate, and unused if the output
Chris@14: 	 * has OneSamplePerStep.
Chris@14: 	 */
Chris@14: 	bool hasTimestamp;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * Timestamp of the output feature.  This is mandatory if the
Chris@14: 	 * output has VariableSampleRate or if the output has
Chris@14: 	 * FixedSampleRate and hasTimestamp is true, and unused
Chris@14: 	 * otherwise.
Chris@14: 	 */
Chris@14: 	RealTime timestamp;
Chris@14: 
Chris@14:         /**
Chris@14:          * True if an output feature has a specified duration.  This
Chris@14:          * is optional if the output has VariableSampleRate or
Chris@14:          * FixedSampleRate, and and unused if the output has
Chris@14:          * OneSamplePerStep.
Chris@14:          */
Chris@14:         bool hasDuration;
Chris@14: 
Chris@14:         /**
Chris@14:          * Duration of the output feature.  This is mandatory if the
Chris@14:          * output has VariableSampleRate or FixedSampleRate and
Chris@14:          * hasDuration is true, and unused otherwise.
Chris@14:          */
Chris@14:         RealTime duration;
Chris@14: 	
Chris@14: 	/**
Chris@14: 	 * Results for a single sample of this feature.  If the output
Chris@14: 	 * hasFixedBinCount, there must be the same number of values
Chris@14: 	 * as the output's binCount count.
Chris@14: 	 */
Chris@14: 	std::vector<float> values;
Chris@14: 
Chris@14: 	/**
Chris@14: 	 * Label for the sample of this feature.
Chris@14: 	 */
Chris@14: 	std::string label;
Chris@14: 
Chris@14:         Feature() : // defaults for mandatory non-class-type members
Chris@14:             hasTimestamp(false), hasDuration(false) { }
Chris@14:     };
Chris@14: 
Chris@14:     typedef std::vector<Feature> FeatureList;
Chris@14: 
Chris@14:     typedef std::map<int, FeatureList> FeatureSet; // key is output no
Chris@14: 
Chris@14:     /**
Chris@14:      * Process a single block of input data.
Chris@14:      * 
Chris@14:      * If the plugin's inputDomain is TimeDomain, inputBuffers will
Chris@14:      * point to one array of floats per input channel, and each of
Chris@14:      * these arrays will contain blockSize consecutive audio samples
Chris@14:      * (the host will zero-pad as necessary).  The timestamp in this
Chris@14:      * case will be the real time in seconds of the start of the
Chris@14:      * supplied block of samples.
Chris@14:      *
Chris@14:      * If the plugin's inputDomain is FrequencyDomain, inputBuffers
Chris@14:      * will point to one array of floats per input channel, and each
Chris@14:      * of these arrays will contain blockSize/2+1 consecutive pairs of
Chris@14:      * real and imaginary component floats corresponding to bins
Chris@14:      * 0..(blockSize/2) of the FFT output.  That is, bin 0 (the first
Chris@14:      * pair of floats) contains the DC output, up to bin blockSize/2
Chris@14:      * which contains the Nyquist-frequency output.  There will
Chris@14:      * therefore be blockSize+2 floats per channel in total.  The
Chris@14:      * timestamp will be the real time in seconds of the centre of the
Chris@14:      * FFT input window (i.e. the very first block passed to process
Chris@14:      * might contain the FFT of half a block of zero samples and the
Chris@14:      * first half-block of the actual data, with a timestamp of zero).
Chris@14:      *
Chris@14:      * Return any features that have become available after this
Chris@14:      * process call.  (These do not necessarily have to fall within
Chris@14:      * the process block, except for OneSamplePerStep outputs.)
Chris@14:      */
Chris@14:     virtual FeatureSet process(const float *const *inputBuffers,
Chris@14: 			       RealTime timestamp) = 0;
Chris@14: 
Chris@14:     /**
Chris@14:      * After all blocks have been processed, calculate and return any
Chris@14:      * remaining features derived from the complete input.
Chris@14:      */
Chris@14:     virtual FeatureSet getRemainingFeatures() = 0;
Chris@14: 
Chris@14:     /**
Chris@14:      * Used to distinguish between Vamp::Plugin and other potential
Chris@14:      * sibling subclasses of PluginBase.  Do not reimplement this
Chris@14:      * function in your subclass.
Chris@14:      */
Chris@14:     virtual std::string getType() const { return "Feature Extraction Plugin"; }
Chris@14: 
Chris@14: protected:
Chris@14:     Plugin(float inputSampleRate) :
Chris@14: 	m_inputSampleRate(inputSampleRate) { }
Chris@14: 
Chris@14:     float m_inputSampleRate;
Chris@14: };
Chris@14: 
Chris@14: }
Chris@14: 
Chris@14: _VAMP_SDK_PLUGSPACE_END(Plugin.h)
Chris@14: 
Chris@14: #endif
Chris@14: 
Chris@14: 
Chris@14: