Here are the classes, structs, unions and interfaces with brief descriptions:

_VampFeature
_VampFeatureList
_VampFeatureUnion
_VampFeatureV2
_VampOutputDescriptor
_VampParameterDescriptor	C language API for Vamp plugins
_VampPluginDescriptor
AmplitudeFollower	Example plugin implementing the SuperCollider amplitude follower function
FixedTempoEstimator::D
Vamp::Plugin::Feature
FixedTempoEstimator	Example plugin that estimates the tempo of a short fixed-tempo sample
Vamp::Plugin::OutputDescriptor
Vamp::PluginBase::ParameterDescriptor
PercussionOnsetDetector	Example plugin that detects percussive events
Vamp::Plugin	Vamp::Plugin is a base class for plugin instance classes that provide feature extraction from audio or related data
Vamp::PluginAdapter< P >	PluginAdapter turns a PluginAdapterBase into a specific wrapper for a particular plugin implementation
Vamp::PluginAdapterBase	PluginAdapter and PluginAdapterBase provide a wrapper class that a plugin library can use to make its C++ Vamp::Plugin objects available through the Vamp C API
Vamp::PluginBase	A base class for plugins with optional configurable parameters, programs, etc
Vamp::HostExt::PluginBufferingAdapter	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
Vamp::HostExt::PluginChannelAdapter	PluginChannelAdapter is a Vamp plugin adapter that implements a policy for management of plugins that expect a different number of input channels from the number actually available in the source audio data
Vamp::PluginHostAdapter	PluginHostAdapter is a wrapper class that a Vamp host can use to make the C-language VampPluginDescriptor object appear as a C++ Vamp::Plugin object
Vamp::HostExt::PluginInputDomainAdapter	PluginInputDomainAdapter is a Vamp plugin adapter that converts time-domain input into frequency-domain input for plugins that need it
Vamp::HostExt::PluginLoader	Vamp::HostExt::PluginLoader is a convenience class for discovering and loading Vamp plugins using the typical plugin-path, library naming, and categorisation conventions described in the Vamp SDK documentation
Vamp::HostExt::PluginSummarisingAdapter	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
Vamp::HostExt::PluginWrapper	PluginWrapper is a simple base class for adapter plugins
PowerSpectrum	Example plugin that returns a power spectrum calculated (trivially) from the frequency domain representation of each block of audio
Vamp::RealTime	RealTime represents time values to nanosecond precision with accurate arithmetic and frame-rate conversion functions
SpectralCentroid	Example plugin that calculates the centre of gravity of the frequency domain representation of each block of audio
ZeroCrossing	Example plugin that calculates the positions and density of zero-crossing points in an audio waveform