cannam@108: cannam@108: Vamp cannam@108: ==== cannam@108: cannam@108: An API for audio analysis and feature extraction plugins. cannam@108: cannam@108: http://www.vamp-plugins.org/ cannam@108: cannam@108: Vamp is an API for C and C++ plugins that process sampled audio data cannam@108: to produce descriptive output (measurements or semantic observations). cannam@108: cannam@108: This is version 2.5 of the Vamp plugin Software Development Kit. cannam@108: cannam@108: Plugins and hosts built with this SDK are binary compatible with those cannam@108: built using version 1.0 of the SDK, with certain restrictions. See cannam@108: the file README.compat for more details. cannam@108: cannam@108: See the file CHANGELOG for a list of the changes in this release. cannam@108: cannam@108: A documentation guide to writing plugins using the Vamp SDK can be cannam@108: found at http://www.vamp-plugins.org/guide.pdf . cannam@108: cannam@108: cannam@108: Compiling and Installing the SDK and Examples cannam@108: ============================================= cannam@108: cannam@108: This SDK is intended for use on Windows, OS/X, Linux, and other POSIX cannam@108: and GNU platforms. cannam@108: cannam@108: Please see the platform-specific README file (README.msvc, README.osx, cannam@108: README.linux) in the build/ directory for details about how to compile cannam@108: and install the SDK, how to build plugin libraries using it, and how cannam@108: to install the example plugins so you can use them in a host. cannam@108: cannam@108: cannam@108: What's In This SDK cannam@108: ================== cannam@108: cannam@108: This SDK contains the following: cannam@108: cannam@108: cannam@108: vamp/vamp.h cannam@108: ----------- cannam@108: cannam@108: The formal C language plugin API for Vamp plugins. cannam@108: cannam@108: A Vamp plugin is a dynamic library (.so, .dll or .dylib depending on cannam@108: platform) exposing one C-linkage entry point (vampGetPluginDescriptor) cannam@108: which returns data defined in the rest of this C header. cannam@108: cannam@108: Although the C API is the official API for Vamp, we don't recommend cannam@108: that you program directly to it. The C++ abstractions found in the cannam@108: vamp-sdk and vamp-hostsdk directories (below) are preferable for most cannam@108: purposes and are more thoroughly documented. cannam@108: cannam@108: cannam@108: vamp-sdk cannam@108: -------- cannam@108: cannam@108: C++ classes for implementing Vamp plugins. cannam@108: cannam@108: Plugins should subclass Vamp::Plugin and then use Vamp::PluginAdapter cannam@108: to expose the correct C API for the plugin. Plugin authors should cannam@108: read vamp-sdk/PluginBase.h and Plugin.h for code documentation. cannam@108: cannam@108: See "examples" below for details of the example plugins in the SDK, cannam@108: from which you are welcome to take code and inspiration. cannam@108: cannam@108: Plugins should link with -lvamp-sdk. cannam@108: cannam@108: cannam@108: vamp-hostsdk cannam@108: ------------ cannam@108: cannam@108: C++ classes for implementing Vamp hosts. cannam@108: cannam@108: Hosts will normally use a Vamp::PluginHostAdapter to convert each cannam@108: plugin's exposed C API back into a useful Vamp::Plugin C++ object. cannam@108: cannam@108: The Vamp::HostExt namespace contains several additional C++ classes to cannam@108: do this work for them, and make the host's life easier: cannam@108: cannam@108: - Vamp::HostExt::PluginLoader provides a very easy interface for a cannam@108: host to discover, load, and find out category information about the cannam@108: available plugins. Most Vamp hosts will probably want to use this cannam@108: class. cannam@108: cannam@108: - Vamp::HostExt::PluginInputDomainAdapter provides a simple means for cannam@108: hosts to handle plugins that want frequency-domain input, without cannam@108: having to convert the input themselves. cannam@108: cannam@108: - Vamp::HostExt::PluginChannelAdapter provides a simple means for cannam@108: hosts to use plugins that do not necessarily support the same number cannam@108: of audio channels as they have available, without having to apply a cannam@108: channel management / mixdown policy themselves. cannam@108: cannam@108: - Vamp::HostExt::PluginBufferingAdapter provides a means for hosts to cannam@108: avoid having to negotiate the input step and block size, instead cannam@108: permitting the host to use any block size they desire (and a step cannam@108: size equal to it). This is particularly useful for "streaming" hosts cannam@108: that cannot seek backwards in the input audio stream and so would cannam@108: otherwise need to implement an additional buffer to support step cannam@108: sizes smaller than the block size. cannam@108: cannam@108: - Vamp::HostExt::PluginSummarisingAdapter provides summarisation cannam@108: methods such as mean and median averages of output features, for use cannam@108: in any context where an available plugin produces individual values cannam@108: but the result that is actually needed is some sort of aggregate. cannam@108: cannam@108: The PluginLoader class can also use the input domain, channel, and cannam@108: buffering adapters automatically to make these conversions transparent cannam@108: to the host if required. cannam@108: cannam@108: Host authors should also refer to the example host code in the host cannam@108: directory of the SDK. cannam@108: cannam@108: Hosts should link with -lvamp-hostsdk. cannam@108: cannam@108: cannam@108: examples cannam@108: -------- cannam@108: cannam@108: Example plugins implemented using the C++ classes. cannam@108: cannam@108: These plugins are intended to be useful examples you can draw code cannam@108: from in order to provide the basic shape and structure of a Vamp cannam@108: plugin. They are also intended to be correct and useful, if simple. cannam@108: cannam@108: - ZeroCrossing calculates the positions and density of zero-crossing cannam@108: points in an audio waveform. cannam@108: cannam@108: - SpectralCentroid calculates the centre of gravity of the frequency cannam@108: domain representation of each block of audio. cannam@108: cannam@108: - PowerSpectrum calculates a power spectrum from the input audio. cannam@108: Actually, it doesn't do any work except calculating power from a cannam@108: cartesian complex FFT output. The work of calculating this frequency cannam@108: domain output is done for it by the host or host SDK; the plugin just cannam@108: needs to declare that it wants frequency domain input. This is the cannam@108: simplest of the example plugins. cannam@108: cannam@108: - AmplitudeFollower is a simple implementation of SuperCollider's cannam@108: amplitude-follower algorithm. cannam@108: cannam@108: - PercussionOnsetDetector estimates the locations of percussive cannam@108: onsets using a simple method described in "Drum Source Separation cannam@108: using Percussive Feature Detection and Spectral Modulation" by Dan cannam@108: Barry, Derry Fitzgerald, Eugene Coyle and Bob Lawlor, ISSC 2005. cannam@108: cannam@108: - FixedTempoEstimator calculates a single beats-per-minute value cannam@108: which is an estimate of the tempo of a piece of music that is assumed cannam@108: to be of fixed tempo, using autocorrelation of a frequency domain cannam@108: energy rise metric. It has several outputs that return intermediate cannam@108: results used in the calculation, and may be a useful example of a cannam@108: plugin having several outputs with varying feature structures. cannam@108: cannam@108: cannam@108: skeleton cannam@108: -------- cannam@108: cannam@108: Skeleton code that could be used as a template for your new plugin cannam@108: implementation. cannam@108: cannam@108: cannam@108: host cannam@108: ---- cannam@108: cannam@108: A simple command-line Vamp host, capable of loading a plugin and using cannam@108: it to process a complete audio file, with its default parameters. cannam@108: cannam@108: This host also contains a number of options for listing the installed cannam@108: plugins and their properties in various formats. For that reason, it cannam@108: isn't really as simple as one might hope. The core of the code is cannam@108: still reasonably straightforward, however. cannam@108: cannam@108: cannam@108: Plugin Lookup and Categorisation cannam@108: ================================ cannam@108: cannam@108: The Vamp API does not officially specify how to load plugin libraries cannam@108: or where to find them. However, the SDK does include a function cannam@108: (Vamp::PluginHostAdapter::getPluginPath()) that returns a recommended cannam@108: directory search path that hosts may use for plugin libraries, and a cannam@108: class (Vamp::HostExt::PluginLoader) that implements a sensible cannam@108: cross-platform lookup policy using this path. We recommend using this cannam@108: class in your host unless you have a good reason not to want to. This cannam@108: implementation also permits the user to set the environment variable cannam@108: VAMP_PATH to override the default path if desired. cannam@108: cannam@108: The policy used by Vamp::HostExt::PluginLoader -- and our cannam@108: recommendation for any host -- is to search each directory in the path cannam@108: returned by getPluginPath for .DLL (on Windows), .so (on Linux, cannam@108: Solaris, BSD etc) or .dylib (on OS/X) files, then to load each one and cannam@108: perform a dynamic name lookup on the vampGetPluginDescriptor function cannam@108: to enumerate the plugins in the library. This operation will cannam@108: necessarily be system-dependent. cannam@108: cannam@108: Vamp also has an informal convention for sorting plugins into cannam@108: functional categories. In addition to the library file itself, a cannam@108: plugin library may install a category file with the same name as the cannam@108: library but .cat extension. The existence and format of this file are cannam@108: not specified by the Vamp API, but by convention the file may contain cannam@108: lines of the format cannam@108: cannam@108: vamp:pluginlibrary:pluginname::General Category > Specific Category cannam@108: cannam@108: which a host may read and use to assign plugins a location within a cannam@108: category tree for display to the user. The expectation is that cannam@108: advanced users may also choose to set up their own preferred category cannam@108: trees, which is why this information is not queried as part of the cannam@108: Vamp plugin's API itself. The Vamp::HostExt::PluginLoader class also cannam@108: provides support for plugin category lookup using this scheme. cannam@108: cannam@108: cannam@108: Licensing cannam@108: ========= cannam@108: cannam@108: This plugin SDK is freely redistributable under a "new-style BSD" cannam@108: licence. See the file COPYING for more details. In short, you may cannam@108: modify and redistribute the SDK and example plugins within any cannam@108: commercial or non-commercial, proprietary or open-source plugin or cannam@108: application under almost any conditions, with no obligation to provide cannam@108: source code, provided you retain the original copyright note. cannam@108: cannam@108: cannam@108: See Also cannam@108: ======== cannam@108: cannam@108: Sonic Visualiser, an interactive open-source graphical audio cannam@108: inspection, analysis and visualisation tool supporting Vamp plugins. cannam@108: http://www.sonicvisualiser.org/ cannam@108: cannam@108: cannam@108: Authors cannam@108: ======= cannam@108: cannam@108: Vamp and the Vamp SDK were designed and made at the Centre for Digital cannam@108: Music at Queen Mary, University of London. cannam@108: cannam@108: The SDK was written by Chris Cannam, copyright (c) 2005-2009 cannam@108: Chris Cannam and QMUL. cannam@108: cannam@108: Mark Sandler and Christian Landone provided ideas and direction, and cannam@108: Mark Levy, Dan Stowell, Martin Gasser and Craig Sapp provided testing cannam@108: and other input for the 1.0 API and SDK. The API also uses some ideas cannam@108: from prior plugin systems, notably DSSI (http://dssi.sourceforge.net) cannam@108: and FEAPI (http://feapi.sourceforge.net). cannam@108: