Mercurial > hg > vamp-docs
view code-docs/doc-overview_source.html @ 7:66d125fb8b42 tip
Added tag vamp-plugin-sdk-v2.7 for changeset 27319718b1f8
| author | Chris Cannam |
|---|---|
| date | Fri, 24 Feb 2017 16:45:00 +0000 |
| parents | 27319718b1f8 |
| children |
line wrap: on
line source
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <meta http-equiv="X-UA-Compatible" content="IE=9"/> <meta name="generator" content="Doxygen 1.8.13"/> <meta name="viewport" content="width=device-width, initial-scale=1"/> <title>VampPluginSDK: doc-overview Source File</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript" src="dynsections.js"></script> <link href="navtree.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="resize.js"></script> <script type="text/javascript" src="navtreedata.js"></script> <script type="text/javascript" src="navtree.js"></script> <script type="text/javascript"> $(document).ready(initResizable); </script> <link href="doxygen.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="top"><!-- do not remove this div, it is closed by doxygen! --> <div id="titlearea"> <table cellspacing="0" cellpadding="0"> <tbody> <tr style="height: 56px;"> <td id="projectalign" style="padding-left: 0.5em;"> <div id="projectname">VampPluginSDK  <span id="projectnumber">2.7</span> </div> </td> </tr> </tbody> </table> </div> <!-- end header part --> <!-- Generated by Doxygen 1.8.13 --> <script type="text/javascript" src="menudata.js"></script> <script type="text/javascript" src="menu.js"></script> <script type="text/javascript"> $(function() { initMenu('',false,false,'search.php','Search'); }); </script> <div id="main-nav"></div> </div><!-- top --> <div id="side-nav" class="ui-resizable side-nav-resizable"> <div id="nav-tree"> <div id="nav-tree-contents"> <div id="nav-sync" class="sync"></div> </div> </div> <div id="splitbar" style="-moz-user-select:none;" class="ui-resizable-handle"> </div> </div> <script type="text/javascript"> $(document).ready(function(){initNavTree('doc-overview_source.html','');}); </script> <div id="doc-content"> <div class="header"> <div class="headertitle"> <div class="title">doc-overview</div> </div> </div><!--header--> <div class="contents"> <a href="doc-overview.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> </div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> /** \mainpage Vamp Plugin SDK</div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> </div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> \section about About Vamp</div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> </div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> Vamp is an API for C and C++ plugins that process sampled audio data</div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> to produce descriptive output (measurements or semantic observations).</div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> Find more information at http://www.vamp-plugins.org/ .</div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> </div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> Although the official API for Vamp plugins is defined in C for maximum</div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> binary compatibility, we strongly recommend using the provided C++</div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> classes in the SDK to implement your own plugins and hosts.</div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span> </div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> \section plugins For Plugins</div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> </div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> Plugins should subclass Vamp::Plugin, and then use a</div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> Vamp::PluginAdapter to expose the correct C API for the plugin. Read</div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> the documentation for Vamp::PluginBase and Vamp::Plugin before</div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> starting.</div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> </div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> Plugins should be compiled and linked into dynamic libraries using the</div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> usual convention for your platform, and should link (preferably</div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> statically) with -lvamp-sdk. Any number of plugins can reside in a</div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> single dynamic library. See plugins.cpp in the example plugins</div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> directory for the sort of code that will need to accompany your plugin</div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> class or classes, to make it possible for a host to look up your</div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span> plugins properly.</div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> </div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> Please read the relevant README file for your platform found in the</div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span> Vamp SDK build/ directory, for details about how to ensure the</div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span> resulting dynamic library exports the correct linker symbols.</div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span> </div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span> The following example plugins are provided. You may legally reuse any</div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> amount of the code from these examples in any plugins you write,</div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span> whether proprietary or open-source.</div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span> </div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span>  - ZeroCrossing calculates the positions and density of zero-crossing</div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span>  points in an audio waveform.</div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span> </div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span>  - SpectralCentroid calculates the centre of gravity of the frequency</div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span>  domain representation of each block of audio.</div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span> </div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span>  - PowerSpectrum calculates a power spectrum from the input audio.</div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span>  Actually, it doesn't do any work except calculating power from a</div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span>  cartesian complex FFT output. The work of calculating this frequency</div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span>  domain output is done for it by the host or host SDK; the plugin just</div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span>  needs to declare that it wants frequency domain input. This is the</div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span>  simplest of the example plugins.</div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span> </div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span>  - AmplitudeFollower is a simple implementation of SuperCollider's</div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span>  amplitude-follower algorithm.</div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span> </div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span>  - PercussionOnsetDetector estimates the locations of percussive</div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span>  onsets using a simple method described in "Drum Source Separation</div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span>  using Percussive Feature Detection and Spectral Modulation" by Dan</div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span>  Barry, Derry Fitzgerald, Eugene Coyle and Bob Lawlor, ISSC 2005.</div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span> </div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span>  - FixedTempoEstimator calculates a single beats-per-minute value</div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span>  which is an estimate of the tempo of a piece of music that is assumed</div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span>  to be of fixed tempo, using autocorrelation of a frequency domain</div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span>  energy rise metric. It has several outputs that return intermediate</div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span>  results used in the calculation, and may be a useful example of a</div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span>  plugin having several outputs with varying feature structures.</div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span> </div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span> Plugin authors should also read the Programmer's Guide at</div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span> http://vamp-plugins.org/guide.pdf .</div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span> </div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span> \section hosts For Hosts</div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span> </div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span> Hosts will normally use a Vamp::PluginHostAdapter to convert each</div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span> plugin's exposed C API back into a useful Vamp::Plugin C++ object.</div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span> </div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span> The Vamp::HostExt namespace contains several additional C++ classes to</div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span> do this work for them, and make the host's life easier:</div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span> </div><div class="line"><a name="l00076"></a><span class="lineno"> 76</span>  - Vamp::HostExt::PluginLoader provides a very easy interface for a</div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span>  host to discover, load, and find out category information about the</div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span>  available plugins. Most Vamp hosts will probably want to use this</div><div class="line"><a name="l00079"></a><span class="lineno"> 79</span>  class.</div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span> </div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span>  - Vamp::HostExt::PluginInputDomainAdapter provides a simple means for</div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span>  hosts to handle plugins that want frequency-domain input, without</div><div class="line"><a name="l00083"></a><span class="lineno"> 83</span>  having to convert the input themselves.</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span> </div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span>  - Vamp::HostExt::PluginChannelAdapter provides a simple means for</div><div class="line"><a name="l00086"></a><span class="lineno"> 86</span>  hosts to use plugins that do not necessarily support the same number</div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>  of audio channels as they have available, without having to apply a</div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span>  channel management / mixdown policy themselves.</div><div class="line"><a name="l00089"></a><span class="lineno"> 89</span> </div><div class="line"><a name="l00090"></a><span class="lineno"> 90</span>  - Vamp::HostExt::PluginBufferingAdapter provides a means for hosts to</div><div class="line"><a name="l00091"></a><span class="lineno"> 91</span>  avoid having to negotiate the input step and block size, instead</div><div class="line"><a name="l00092"></a><span class="lineno"> 92</span>  permitting the host to use any block size they desire (and a step</div><div class="line"><a name="l00093"></a><span class="lineno"> 93</span>  size equal to it). This is particularly useful for "streaming" hosts</div><div class="line"><a name="l00094"></a><span class="lineno"> 94</span>  that cannot seek backwards in the input audio stream and so would</div><div class="line"><a name="l00095"></a><span class="lineno"> 95</span>  otherwise need to implement an additional buffer to support step</div><div class="line"><a name="l00096"></a><span class="lineno"> 96</span>  sizes smaller than the block size.</div><div class="line"><a name="l00097"></a><span class="lineno"> 97</span> </div><div class="line"><a name="l00098"></a><span class="lineno"> 98</span>  - Vamp::HostExt::PluginSummarisingAdapter provides summarisation</div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span>  methods such as mean and median averages of output features, for use</div><div class="line"><a name="l00100"></a><span class="lineno"> 100</span>  in any context where an available plugin produces individual values</div><div class="line"><a name="l00101"></a><span class="lineno"> 101</span>  but the result that is actually needed is some sort of aggregate.</div><div class="line"><a name="l00102"></a><span class="lineno"> 102</span> </div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span> The PluginLoader class can also use the input domain, channel, and</div><div class="line"><a name="l00104"></a><span class="lineno"> 104</span> buffering adapters automatically to make these conversions transparent</div><div class="line"><a name="l00105"></a><span class="lineno"> 105</span> to the host if required.</div><div class="line"><a name="l00106"></a><span class="lineno"> 106</span> </div><div class="line"><a name="l00107"></a><span class="lineno"> 107</span> Host authors should also refer to the example host code in the host</div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span> directory of the SDK.</div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span> </div><div class="line"><a name="l00110"></a><span class="lineno"> 110</span> Hosts should link with -lvamp-hostsdk.</div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span> </div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span> (The following notes in this section are mostly relevant for</div><div class="line"><a name="l00113"></a><span class="lineno"> 113</span> developers that are not using the HostExt classes, or that wish to</div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span> know more about the policy they implement.)</div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span> </div><div class="line"><a name="l00116"></a><span class="lineno"> 116</span> The Vamp API does not officially specify how to load plugin libraries</div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span> or where to find them. However, the SDK does include a function</div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span> (Vamp::PluginHostAdapter::getPluginPath()) that returns a recommended</div><div class="line"><a name="l00119"></a><span class="lineno"> 119</span> directory search path that hosts may use for plugin libraries, and a</div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span> class (Vamp::HostExt::PluginLoader) that implements a sensible</div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span> cross-platform lookup policy using this path. We recommend using this</div><div class="line"><a name="l00122"></a><span class="lineno"> 122</span> class in your host unless you have a good reason not to want to. This</div><div class="line"><a name="l00123"></a><span class="lineno"> 123</span> implementation also permits the user to set the environment variable</div><div class="line"><a name="l00124"></a><span class="lineno"> 124</span> VAMP_PATH to override the default path if desired.</div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span> </div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span> The policy used by Vamp::HostExt::PluginLoader -- and our</div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span> recommendation for any host -- is to search each directory in this</div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span> path for .DLL (on Windows), .so (on Linux, Solaris, BSD etc) or .dylib</div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span> (on OS/X) files, then to load each one and perform a dynamic name</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span> lookup on the vampGetPluginDescriptor function to enumerate the</div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span> plugins in the library. The example host has some code that may help,</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span> but this operation will necessarily be system-dependent.</div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span> </div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span> Vamp also has an informal convention for sorting plugins into</div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span> functional categories. In addition to the library file itself, a</div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span> plugin library may install a category file with the same name as the</div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span> library but .cat extension. The existence and format of this file are</div><div class="line"><a name="l00138"></a><span class="lineno"> 138</span> not specified by the Vamp API, but by convention the file may contain</div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span> lines of the format</div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span> </div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span> \code</div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span> vamp:pluginlibrary:pluginname::General Category > Specific Category</div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span> \endcode</div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span> </div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span> which a host may read and use to assign plugins a location within a</div><div class="line"><a name="l00146"></a><span class="lineno"> 146</span> category tree for display to the user. The expectation is that</div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span> advanced users may also choose to set up their own preferred category</div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span> trees, which is why this information is not queried as part of the</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span> Vamp plugin's API itself. The Vamp::HostExt::PluginLoader class also</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span> provides support for plugin category lookup using this scheme.</div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span> </div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span> \section license License</div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span> </div><div class="line"><a name="l00154"></a><span class="lineno"> 154</span> This plugin SDK is freely redistributable under a "new-style BSD"</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span> licence. See the file COPYING for more details. In short, you may</div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span> modify and redistribute the SDK and example plugins within any</div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span> commercial or non-commercial, proprietary or open-source plugin or</div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span> application under almost any conditions, with no obligation to provide</div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span> source code, provided you retain the original copyright note.</div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span> </div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span> </div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span> */</div></div><!-- fragment --></div><!-- contents --> </div><!-- doc-content --> <!-- start footer part --> <div id="nav-path" class="navpath"><!-- id is needed for treeview function! --> <ul> <li class="navelem"><a class="el" href="dir_68267d1309a1af8e8297ef4c3efbcdba.html">src</a></li><li class="navelem"><a class="el" href="doc-overview.html">doc-overview</a></li> <li class="footer">Generated by <a href="http://www.doxygen.org/index.html"> <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.8.13 </li> </ul> </div> </body> </html>