cannam@14: cannam@14: Vamp cannam@14: ==== cannam@14: cannam@14: An API for audio analysis and feature extraction plugins. cannam@14: cannam@44: http://www.vamp-plugins.org/ cannam@44: cannam@14: Vamp is an API for C and C++ plugins that process sampled audio data cannam@18: to produce descriptive output (measurements or semantic observations). cannam@14: cannam@237: This is version 2.0 of the Vamp plugin Software Development Kit. cannam@78: Plugins and hosts built with this SDK are binary compatible with those cannam@239: built using version 1.0 of the SDK. See CHANGELOG for a list of the cannam@239: changes in this release. cannam@78: cannam@215: A documentation guide to writing plugins using the Vamp SDK can be cannam@215: found at http://www.vamp-plugins.org/guide.pdf . cannam@215: cannam@239: cannam@239: Compiling and Installing the SDK and Examples cannam@239: ============================================= cannam@239: cannam@239: This SDK is intended for use on Windows, OS/X, Linux, and other POSIX cannam@239: and GNU platforms. cannam@239: cannam@239: Please see the platform-specific README file (README.msvc, README.osx, cannam@239: README.linux) in the build/ directory for details about how to compile cannam@239: and install the SDK, how to build plugin libraries using it, and how cannam@239: to install the example plugins so you can use them in a host. cannam@239: cannam@239: cannam@239: What's In This SDK cannam@239: ================== cannam@239: cannam@78: This SDK contains the following: cannam@14: cannam@239: cannam@239: vamp/vamp.h cannam@239: ----------- cannam@14: cannam@14: The formal C language plugin API for Vamp plugins. cannam@14: cannam@14: A Vamp plugin is a dynamic library (.so, .dll or .dylib depending on cannam@14: platform) exposing one C-linkage entry point (vampGetPluginDescriptor) cannam@14: which returns data defined in the rest of this C header. cannam@14: cannam@78: Although the C API is the official API for Vamp, we don't recommend cannam@239: that you program directly to it. The C++ abstractions found in the cannam@239: vamp-sdk and vamp-hostsdk directories (below) are preferable for most cannam@239: purposes and are more thoroughly documented. cannam@14: cannam@239: cannam@239: vamp-sdk cannam@239: -------- cannam@14: cannam@237: C++ classes for implementing Vamp plugins. cannam@18: cannam@78: Plugins should subclass Vamp::Plugin and then use Vamp::PluginAdapter cannam@78: to expose the correct C API for the plugin. Plugin authors should cannam@239: read vamp-sdk/PluginBase.h and Plugin.h for code documentation. cannam@18: cannam@239: See "examples" below for details of the example plugins in the SDK, cannam@239: from which you are welcome to take code and inspiration. cannam@239: cannam@239: Plugins should link with -lvamp-sdk. cannam@239: cannam@239: cannam@239: vamp-hostsdk cannam@239: ------------ cannam@14: cannam@237: C++ classes for implementing Vamp hosts. cannam@64: cannam@239: Hosts will normally use a Vamp::PluginHostAdapter to convert each cannam@239: plugin's exposed C API back into a useful Vamp::Plugin C++ object. cannam@237: cannam@237: The Vamp::HostExt namespace contains several additional C++ classes to cannam@239: do this work for them, and make the host's life easier: cannam@64: cannam@239: - Vamp::HostExt::PluginLoader provides a very easy interface for a cannam@239: host to discover, load, and find out category information about the cannam@239: available plugins. Most Vamp hosts will probably want to use this cannam@239: class. cannam@64: cannam@239: - Vamp::HostExt::PluginInputDomainAdapter provides a simple means for cannam@239: hosts to handle plugins that want frequency-domain input, without cannam@239: having to convert the input themselves. cannam@64: cannam@239: - Vamp::HostExt::PluginChannelAdapter provides a simple means for cannam@239: hosts to use plugins that do not necessarily support the same number cannam@239: of audio channels as they have available, without having to apply a cannam@239: channel management / mixdown policy themselves. cannam@64: cannam@239: - Vamp::HostExt::PluginBufferingAdapter provides a means for hosts to cannam@239: avoid having to negotiate the input step and block size, instead cannam@239: permitting the host to use any block size they desire (and a step cannam@239: size equal to it). This is particularly useful for "streaming" hosts cannam@239: that cannot seek backwards in the input audio stream and so would cannam@239: otherwise need to implement an additional buffer to support step cannam@239: sizes smaller than the block size. cannam@125: cannam@239: - Vamp::HostExt::PluginSummarisingAdapter provides summarisation cannam@239: methods such as mean and median averages of output features, for use cannam@239: in any context where an available plugin produces individual values cannam@239: but the result that is actually needed is some sort of aggregate. cannam@64: cannam@239: The PluginLoader class can also use the input domain, channel, and cannam@239: buffering adapters automatically to make these conversions transparent cannam@239: to the host if required. cannam@14: cannam@239: Host authors should also refer to the example host code in the host cannam@239: directory of the SDK. cannam@14: cannam@239: Hosts should link with -lvamp-hostsdk. cannam@239: cannam@239: cannam@239: examples cannam@239: -------- cannam@239: cannam@239: Example plugins implemented using the C++ classes. cannam@239: cannam@239: These plugins are intended to be useful examples you can draw code cannam@239: from in order to provide the basic shape and structure of a Vamp cannam@239: plugin. They are also intended to be correct and useful, if simple. cannam@239: cannam@239: - ZeroCrossing calculates the positions and density of zero-crossing cannam@239: points in an audio waveform. cannam@239: cannam@239: - SpectralCentroid calculates the centre of gravity of the frequency cannam@239: domain representation of each block of audio. cannam@239: cannam@242: - PowerSpectrum calculates a power spectrum from the input audio. cannam@244: Actually, it doesn't do any work except calculating power from a cannam@244: cartesian complex FFT output. The work of calculating this frequency cannam@244: domain output is done for it by the host or host SDK; the plugin just cannam@244: needs to declare that it wants frequency domain input. This is the cannam@244: simplest of the example plugins. cannam@242: cannam@239: - AmplitudeFollower is a simple implementation of SuperCollider's cannam@239: amplitude-follower algorithm. cannam@239: cannam@239: - PercussionOnsetDetector estimates the locations of percussive cannam@239: onsets using a simple method described in "Drum Source Separation cannam@239: using Percussive Feature Detection and Spectral Modulation" by Dan cannam@239: Barry, Derry Fitzgerald, Eugene Coyle and Bob Lawlor, ISSC 2005. cannam@239: cannam@239: - FixedTempoEstimator calculates a single beats-per-minute value cannam@239: which is an estimate of the tempo of a piece of music that is assumed cannam@239: to be of fixed tempo, using autocorrelation of a frequency domain cannam@239: energy rise metric. It has several outputs that return intermediate cannam@239: results used in the calculation, and may be a useful example of a cannam@239: plugin having several outputs with varying feature structures. cannam@239: cannam@239: cannam@239: host cannam@239: ---- cannam@14: cannam@16: A simple command-line Vamp host, capable of loading a plugin and using cannam@16: it to process a complete audio file, with its default parameters. cannam@14: cannam@250: This host also contains a number of options for listing the installed cannam@250: plugins and their properties in various formats. For that reason, it cannam@250: isn't really as simple as one might hope. The core of the code is cannam@250: still reasonably straightforward, however. cannam@250: cannam@40: cannam@40: Plugin Lookup and Categorisation cannam@40: ================================ cannam@40: cannam@40: The Vamp API does not officially specify how to load plugin libraries cannam@40: or where to find them. However, the SDK does include a function cannam@40: (Vamp::PluginHostAdapter::getPluginPath()) that returns a recommended cannam@75: directory search path that hosts may use for plugin libraries, and a cannam@75: class (Vamp::HostExt::PluginLoader) that implements a sensible cannam@75: cross-platform lookup policy using this path. We recommend using this cannam@75: class in your host unless you have a good reason not to want to. This cannam@75: implementation also permits the user to set the environment variable cannam@75: VAMP_PATH to override the default path if desired. cannam@40: cannam@75: The policy used by Vamp::HostExt::PluginLoader -- and our cannam@75: recommendation for any host -- is to search each directory in the path cannam@75: returned by getPluginPath for .DLL (on Windows), .so (on Linux, cannam@75: Solaris, BSD etc) or .dylib (on OS/X) files, then to load each one and cannam@75: perform a dynamic name lookup on the vampGetPluginDescriptor function cannam@75: to enumerate the plugins in the library. This operation will cannam@75: necessarily be system-dependent. cannam@40: cannam@40: Vamp also has an informal convention for sorting plugins into cannam@40: functional categories. In addition to the library file itself, a cannam@40: plugin library may install a category file with the same name as the cannam@40: library but .cat extension. The existence and format of this file are cannam@40: not specified by the Vamp API, but by convention the file may contain cannam@40: lines of the format cannam@40: cannam@40: vamp:pluginlibrary:pluginname::General Category > Specific Category cannam@40: cannam@40: which a host may read and use to assign plugins a location within a cannam@40: category tree for display to the user. The expectation is that cannam@40: advanced users may also choose to set up their own preferred category cannam@40: trees, which is why this information is not queried as part of the cannam@75: Vamp plugin's API itself. The Vamp::HostExt::PluginLoader class also cannam@75: provides support for plugin category lookup using this scheme. cannam@32: cannam@14: cannam@14: Licensing cannam@14: ========= cannam@14: cannam@18: This plugin SDK is freely redistributable under a "new-style BSD" cannam@42: licence. See the file COPYING for more details. In short, you may cannam@42: modify and redistribute the SDK and example plugins within any cannam@42: commercial or non-commercial, proprietary or open-source plugin or cannam@42: application under almost any conditions, with no obligation to provide cannam@42: source code, provided you retain the original copyright note. cannam@14: cannam@14: cannam@14: See Also cannam@14: ======== cannam@14: cannam@14: Sonic Visualiser, an interactive open-source graphical audio cannam@14: inspection, analysis and visualisation tool supporting Vamp plugins. cannam@35: http://www.sonicvisualiser.org/ cannam@14: cannam@14: cannam@44: Authors cannam@44: ======= cannam@44: cannam@44: Vamp and the Vamp SDK were designed and made at the Centre for Digital cannam@64: Music at Queen Mary, University of London. cannam@44: cannam@127: The SDK was written by Chris Cannam, copyright (c) 2005-2008 cannam@64: Chris Cannam and QMUL. cannam@64: cannam@64: Mark Sandler and Christian Landone provided ideas and direction, and cannam@64: Mark Levy, Dan Stowell, Martin Gasser and Craig Sapp provided testing cannam@64: and other input for the 1.0 API and SDK. The API also uses some ideas cannam@64: from prior plugin systems, notably DSSI (http://dssi.sourceforge.net) cannam@64: and FEAPI (http://feapi.sourceforge.net). cannam@64: